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  Regarding faults in screw pumps, we at Anhui Shengshi Datang have some effective solutions. First, ensure that no foreign objects enter the pump body. If solid debris enters the pump body, it can damage the rubber stator of the progressive screw pump. Therefore, it is crucial to prevent debris from entering the pump chamber. Some systems install a grinder before the pump, while others use a screen or filter to block debris from entering the pump. Screens should be cleaned promptly to prevent clogging.   Second, avoid operating the pump without material. The progressive screw pump absolutely must not run dry. If dry running occurs, the rubber stator can instantly overheat due to dry friction and burn out. Therefore, having a properly functioning grinder and clear screens are essential conditions for the normal operation of the pump. For this reason, some pumps are equipped with a dry-run protection device. When material supply is interrupted, the self-priming capability of the pump creates a vacuum in the chamber, which triggers the vacuum device to stop the pump.   Third, maintain a constant outlet pressure. The progressive screw pump is a positive displacement rotary pump. If the outlet is blocked, the pressure will gradually rise, potentially exceeding the predetermined value. This causes a sharp increase in the motor load, and the load on related transmission components may also exceed design limits. In severe cases, this can lead to motor burnout or broken transmission parts. To prevent pump damage, a bypass relief valve is usually installed at the outlet to stabilize the discharge pressure and ensure normal pump operation. Fourth, reasonable selection of pump speed. The flow rate of the progressive screw pump has a linear relationship with its speed. Compared to low-speed pumps, high-speed pumps can increase flow and head, but power consumption increases significantly. High speed accelerates the wear between the rotor and stator, inevitably leading to premature pump failure. Furthermore, the stator and rotor of high-speed pumps are shorter and wear out more easily, thus shortening the pump's service life.   Using a gear reducer or variable speed drive to reduce the speed, keeping it within a reasonable range below 300 revolutions per minute, can extend the pump's service life several times compared to high-speed operation.   Of course, there are many other maintenance methods for progressive screw pumps, which requires us to be more attentive during daily use. Careful observation will contribute significantly to proper pump maintenance.   How should faults in progressive screw pumps be handled? This article will mainly introduce methods for troubleshooting progressive screw pumps. 1. Pump body vibrates violently or produces noise: A. Causes:​ Pump not installed securely or installed too high; damage to the motor's ball bearings; bent pump shaft or misalignment (non-concentricity or non-parallelism) between the pump shaft and the motor shaft. B. Solutions:​ Secure the pump properly or lower its installation height; replace the motor's ball bearings; straighten the bent pump shaft or correct the relative position between the pump and the motor. 2. Transmission shaft or motor bearings overheating: A. Causes:​ Lack of lubricant or bearing failure. B. Solutions:​ Add lubricant or replace the bearings. 3. Pump fails to deliver water: Causes:​ Pump body and suction pipe not fully primed with water; dynamic water level below the pump strainer; cracked suction pipe, etc.   The sealing surface between the screw and the housing is a spatial curved surface. On this surface, there are non-sealing areas such as ab or de, which form many triangular notches (abc, def) with the screw grooves. These triangular notches form flow channels for the liquid, connecting the groove A of the driving screw to grooves B and C on the driven screw. Grooves B and C, in turn, spiral along their helices to the back side and connect with grooves D and E on the back, respectively. Because the sealing surface where grooves D and E connect with groove F (which belongs to another helix) also has triangular notches similar to a'b'c' on the front side, D, F, and E are also connected. Thus, grooves A-B-C-D-E-A form an "∞"-shaped sealed space (If single-start threads were used, the grooves would simply follow the screw axis and connect the suction and discharge ports, making sealing impossible). It's conceivable that many independent "∞"-shaped sealed spaces are formed along such a screw. The axial length occupied by each sealed space is exactly equal to the lead (t) of the screw. Therefore, to separate the suction and discharge ports, the length of the threaded section of the screw must be at least greater than one lead.  

  Stainless steel submersible pumps are widely used in drainage applications across industries such as pharmaceuticals, environmental protection, food, chemical, and power due to their characteristics of corrosion resistance, hygiene, energy efficiency, environmental friendliness, non-clogging, high flow rate, and strong passage capability. Anhui Shengshi Datang will study together with everyone.   I. Common Causes and Solutions for Insufficient Flow or No Water Output in Stainless Steel Submersible Pumps: 1. The installation height of the pump is too high, resulting in insufficient impeller immersion depth and reduced water output. Control the allowable deviation of the installation elevation and avoid arbitrary adjustments. 2. The pump rotates in the reverse direction. Before trial operation, run the motor without load to ensure the rotation direction matches the pump. If this occurs during operation, check whether the power phase sequence has changed. 3. The outlet valve cannot open. Inspect the valve and perform regular maintenance. 4. The outlet pipeline is blocked, or the impeller is clogged. Clear blockages in the pipeline and impeller, and regularly remove debris from the reservoir. 5. The lower wear ring of the pump is severely worn or blocked by debris. Clean the debris or replace the wear ring. 6. The density or viscosity of the pumped liquid is too high. Identify the cause of the change in liquid properties and address it. 7. The impeller is detached or damaged. Reinforce or replace the impeller. 8. When multiple pumps share a common discharge pipeline, a check valve is not installed or the check valve is not sealing properly. Install or replace the check valve after inspection.   II. Causes of Abnormal Vibration and Instability During Operation of Stainless Steel Submersible Pumps: 1. The anchor bolts of the pump base are not tightened or have become loose. Tighten all anchor bolts evenly. 2. The outlet pipeline lacks independent support, causing pipeline vibration to affect the pump. Provide independent and stable support for the outlet pipeline, ensuring the pump’s outlet flange does not bear weight. 3. The impeller is unbalanced, damaged, or loosely installed. Repair or replace the impeller. 4. The upper or lower bearings of the pump are damaged. Replace the bearings.   III. Causes of Overcurrent, Motor Overload, or Overheating in Stainless Steel Submersible Pumps: 1. The operating voltage is too low or too high. Check the power supply voltage and adjust it. 2. There is friction between rotating and stationary parts inside the pump, or between the impeller and the seal ring. Identify the location of the friction and resolve the issue. 3. Low head and high flow cause a mismatch between the motor power and the pump characteristics. Adjust the valve to reduce the flow, ensuring the motor power matches the pump. 4. The pumped liquid has high density or viscosity. Investigate the cause of the change in liquid properties and adjust the pump’s operating conditions. 5. The bearings are damaged. Replace the bearings at both ends of the motor. IV. Causes and Solutions for Low Insulation Resistance in Stainless Steel Submersible Pumps: 1. The cable ends were submerged during installation, or the power or signal cable was damaged, allowing water ingress. Replace the cable or signal wire, and dry the motor. 2. The mechanical seal is worn or not properly installed. Replace the upper and lower mechanical seals, and dry the motor. 3. The O-rings have aged and lost their function. Replace all sealing rings and dry the motor.   V. Causes and Solutions for Visible Water Leakage in Pipes or Flange Connections of Stainless Steel Submersible Pump Systems: 1. The pipeline itself has defects and was not pressure-tested. 2. The gasket connection at the flange joint was not properly handled. 3. The flange bolts were not tightened correctly. Repair or replace defective pipes, realign misaligned pipes, and ensure bolts are inserted and tightened freely. After installation, conduct a pressure and leakage test on the entire system. Replace components as necessary.   VI. Internal Leakage in Stainless Steel Submersible Pumps: Leakage in the pump can lead to insulation failure, bearing damage, alarm activation, and forced shutdown. The main causes include failure of dynamic seals (mechanical seals) or static seals (cable inlet seals, O-rings), and damage to power or signal cables allowing water ingress. Alarms such as water immersion, leakage, or humidity may trigger shutdowns. Before installation, inspect the quality of all sealing components. Ensure proper contact between sealing surfaces during installation. Before operation, check the motor’s phase-to-phase and ground insulation resistance, and ensure all alarm sensors are functional. If leakage occurs during operation, replace all damaged seals and cables, and dry the motor. Do not reuse disassembled seals or cables.   VII. Reverse Rotation After Shutdown of Stainless Steel Submersible Pumps: 1. Reverse rotation occurs after the pump motor is powered off, mainly due to failure of the check valve or flap valve in the outlet pipeline. 2. Before installation, inspect the check valve for correct orientation and ensure the flap valve is centered and operates flexibly. Regularly inspect the check valve or flap valve during operation, and repair or replace damaged components with quality parts.  

  Fluoroplastic self-priming pumps, also known as the TIZF series fluoroplastic self-priming pumps, are designed and manufactured in accordance with international standards and the manufacturing processes for non-metallic pumps. The pump structure adopts a self-priming design. The pump casing consists of a metal shell lined with fluoroplastic, and all wetted parts are made of fluoroplastic alloy. Components like the pump cover and impeller are manufactured by integrally sintering and pressing metal inserts coated with fluoroplastic. The shaft seal utilizes an advanced external bellows mechanical seal. The stationary ring is made of 99.9% alumina ceramic (or silicon nitride), and the rotating ring is made of PTFE-filled material, ensuring highly stable corrosion resistance, wear resistance, and sealing performance.   A fluoroplastic self-priming pump does not require priming before startup (although the initial installation still requires priming). After a short period of operation, the pump can draw fluid up and commence normal operation through its own action.   Fluoroplastic self-priming pumps can be classified by their operating principle into the following categories: 1.Gas-liquid mixing type (including internal mixing and external mixing). 2.Water ring type. 3.Jet type (including liquid jet and gas jet).     Working process of the gas-liquid mixing self-priming pump: Due to the special structure of the pump casing, a certain amount of water remains in the pump after it stops. When the pump is started again, the rotation of the impeller fully mixes the air in the suction line with the water. This mixture is discharged into the gas-water separation chamber. The gas in the upper part of the separation chamber escapes, while the water in the lower part returns to the impeller to mix again with the remaining air in the suction line. This process continues until all gas in the pump and suction line is expelled, completing the self-priming process and allowing normal pumping.   Water ring self-priming pumps​ integrate a water ring and the pump impeller within a single housing, using the water ring to expel gas and achieve self-priming. Once the pump operates normally, the passage between the water ring and the impeller can be closed off via a valve, and the liquid within the water ring can be drained.   Jet self-priming pumps: consist of a centrifugal pump combined with a jet pump (or ejector). They rely on the ejector device to create a vacuum at the nozzle to achieve suction.   The self-priming height of a fluoroplastic self-priming pump is related to factors such as the front impeller seal clearance, pump speed, and liquid level height in the separation chamber. A smaller front impeller seal clearance results in a greater self-priming height, typically set between 0.3-0.5 mm. If the clearance increases, besides a decrease in self-priming height, the pump's head and efficiency also reduce. The self-priming height increases with the rise in the impeller's peripheral velocity (u2). However, once the maximum self-priming height is reached, further speed increases will not raise the height but only shorten the priming time. If the speed decreases, the self-priming height also decreases. Under other constant conditions, the self-priming height increases with a higher stored water level (but should not exceed the optimal water level for the separation chamber).   To better facilitate gas-liquid mixing within the self-priming pump, the impeller should have fewer blades, increasing the pitch of the blade grid. It is also advisable to use a semi-open impeller (or an impeller with wider flow channels), as this allows the returning water to penetrate more deeply into the impeller blade grid. Most fluoroplastic self-priming pumps are matched with internal combustion engines and mounted on movable carts, making them suitable for field operations.   What is the working principle of a fluoroplastic self-priming pump? For a standard centrifugal pump, if the suction liquid level is below the impeller, it must be primed with water before startup, which is inconvenient. To retain water in the pump, a foot valve is required at the inlet of the suction pipe, but this valve causes significant hydraulic losses during operation. A self-priming pump, as described above, does not require priming before startup (except for the initial installation). After a short operation, it can draw fluid up and begin normal operation. The classification and working principles of the different self-priming types (gas-liquid mixing, water ring, jet) are as previously detailed.

  High-temperature magnetic drive pumps are compact, aesthetically pleasing, small in size, and feature stable, user-friendly operation with low noise levels. They are widely used in chemical, pharmaceutical, petroleum, electroplating, food, film processing, scientific research institutions, defense industries, and other sectors for pumping acids, alkaline solutions, oils, rare and valuable liquids, toxic liquids, volatile liquids, and in circulating water equipment, as well as for supporting high-speed machinery. They are particularly suitable for liquids that are prone to leakage, evaporation, combustion, or explosion. It is best to choose an explosion-proof motor for such pumps. Advantages of High-Temperature Magnetic Drive Pumps: 1. No need to install a foot valve or prime the pump. 2. The pump shaft is changed from dynamic sealing to enclosed static sealing, completely avoiding media leakage. 3. No independent lubrication or cooling water is required, reducing energy consumption. 4. Power transmission is changed from coupling drive to synchronous dragging, eliminating contact and friction. This results in low power consumption, high efficiency, and provides damping and vibration reduction, minimizing the impact of motor vibration on the pump and pump cavitation vibration on the motor. 5. In case of overload, the inner and outer magnetic rotors slip relative to each other, protecting the motor and pump. 6. If the driven component of the magnetic drive operates under overload conditions or the rotor jams, the driving and driven components of the magnetic drive will automatically slip, protecting the pump. Under these conditions, the permanent magnets in the magnetic drive will experience eddy current losses and magnetic losses due to the alternating magnetic field of the driving rotor, causing the temperature of the permanent magnets to rise and leading to the failure of the magnetic drive slip.     Precautions for Using High-Temperature Magnetic Drive Pumps: 1. Prevent Particle Entry (1) Do not allow ferromagnetic impurities or particles to enter the magnetic drive or the bearing friction pair. (2) After transporting media prone to crystallization or sedimentation, flush promptly (fill the pump cavity with clean water after stopping the pump, run for 1 minute, then drain completely) to ensure the service life of the sliding bearings. (3) When pumping media containing solid particles, install a filter at the pump inlet.   2. Prevent Demagnetization (1) The magnetic torque must not be designed too small. (2) Operate within the specified temperature conditions; strictly avoid exceeding the maximum allowable media temperature. A platinum resistance temperature sensor can be installed on the outer surface of the isolation sleeve to monitor the temperature rise in the gap area, enabling an alarm or shutdown if the temperature limit is exceeded.   3. Prevent Dry Running (1) Strictly prohibit dry running (operating without liquid). (2) Strictly avoid running the pump dry or allowing the media to be completely drained (cavitation). (3) Do not operate the pump continuously for more than 2 minutes with the discharge valve closed, to prevent overheating and failure of the magnetic drive.   4. Not for Use in Pressurized Systems:​ Due to the existence of certain clearances in the pump cavity and the use of "static bearings," this series of pumps must absolutely not be used in pressurized systems (neither positive pressure nor vacuum/negative pressure is acceptable).   5. Timely Cleaning:​ For media that are prone to sedimentation or crystallization, clean the pump promptly after use and drain any residual liquid from the pump.   6. Regular Inspection:​ After 1000 hours of normal operation, disassemble and inspect the wear of the bearings and the end face dynamic ring. Replace any worn-out vulnerable parts that are no longer suitable for use.   7. Inlet Filtration:​ If the pumped medium contains solid particles, install a strainer at the pump inlet. If it contains ferromagnetic particles, a magnetic filter is required.   8. Operating Environment:​ The ambient temperature during pump operation should be less than 40°C, and the motor temperature rise should not exceed 75°C.   9. Media and Temperature Limits:​ The pumped medium and its temperature must be within the allowable range of the pump materials. For engineering plastic pumps, the temperature should be <60°C; for metal pumps, <100°C. The suction pressure should not exceed 0.2MPa, the maximum working pressure is 1.6MPa, for liquids with a density not greater than 1600 kg/m³ and a viscosity not greater than 30 x 10⁻⁶ m²/s, and which do not contain hard particles or fibers. High-temperature magnetic drive pumps replace dynamic seals with static seals, making the pump's wetted parts fully enclosed. This solves the unavoidable running, dripping, and leaking issues associated with the mechanical seals of other pumps. Manufactured using highly corrosion-resistant materials such as engineering plastics, alumina ceramics, and stainless steel, these pumps offer excellent corrosion resistance and ensure the pumped media remains uncontaminated.

In industries such as chemicals, pharmaceuticals, and new materials, the tank farm area serves as a critical transfer point connecting raw material supply with workshop processes. Especially for long-distance liquid transfer from storage tanks to workshops, ensuring safety, sealing performance, and stable conveying becomes the core of equipment selection. Magnetic pumps, with their leak-free and explosion-proof structure, have become the preferred solution for transferring raw materials and finished products in tank farm systems. 1. Transfer Scenario: Challenges from the “Tank Area” to the Workshop A “tank area” refers to the zone for raw material unloading, product loading, and intermediate material storage. In actual operations, liquids are transferred from tank trucks into storage tanks, typically within a distance of around 20 meters. Next, the material must be conveyed stably through pipelines to workshops located more than 50 meters away. This type of transfer scenario has three typical characteristics: A. Long distance and high head requirements: Pipeline lengths often exceed 50 meters; head must account for pipeline resistance and elevation differences. B. Media are usually volatile or toxic: Such as alcohols, ketones, and organic solvents—requiring excellent system sealing. C. High explosion-proof requirements and limited maintenance access: Usually located in hazardous areas, demanding reliable, low-maintenance equipment. 2. Why Magnetic Pumps Are Suitable for Tank Area Transfer Shengshi Datang magnetic pumps use magnetic coupling drive and require no mechanical seals, eliminating leakage risks structurally. For toxic, flammable, or volatile media, magnetic pumps offer true zero-leakage performance. Through optimized flow channels and efficient magnetic drive systems, Shengshi Datang magnetic pumps ensure stable output even during long-distance transfer, making them especially suitable for high-frequency transfers from tank farms to workshops. 3. Key Points for Pump Selection A. Head Matching: For pipelines exceeding 50 meters, account for frictional and local resistance, as well as tank liquid level and workshop elevation. It is recommended to design the pump head at 1.2× the actual requirement as a safety margin. B. Material Selection: Wetted parts should be selected according to the medium’s corrosiveness—stainless steel, fluoroplastic lining, or other corrosion-resistant materials. C. Flow Rate Determination: Select based on unloading or process requirements, generally using the maximum required flow to avoid insufficient feeding or frequent start–stop cycles. D. Motor Configuration: Use explosion-proof motors, with a grade not lower than EX d IIB T4, matching the operating conditions to ensure long-term safe operation. E. Cooling Structure: For easily vaporized liquids, choose magnetic pumps with auxiliary cooling circuits to prevent demagnetization of the inner magnet or local cavitation in the pump chamber. 4. Reference Case At a fine chemical plant in East China, ethanol is transferred from the tank area to a workshop around 55 meters away. Initially, mechanical-seal centrifugal pumps were used, but frequent leakage and long maintenance cycles caused issues. They were later replaced with fluoroplastic-lined magnetic pumps equipped with explosion-proof motors and auxiliary cooling loops. After three years of operation, no leakage occurred, and maintenance costs dropped by more than 40%. Long-distance transfer from tank areas to workshops demands high levels of stability and sealing from pumps. Magnetic pumps, with their sealless design and strong corrosion resistance, demonstrate significant advantages in such systems. During selection, factors such as transfer distance, medium characteristics, and site explosion-proof requirements should be thoroughly evaluated. Choosing products from manufacturers with extensive industry experience ensures long-term stable operation. Shengshi Datang Pump Industry’s magnetic pumps have been widely used in such applications and are a reliable choice.

  Centrifugal pumps are critical equipment in the oilfield gathering and transportation process. The mechanical seal is a vital component of the centrifugal pump, used to prevent medium leakage. Failure of the mechanical seal directly affects the stable operation of the equipment, leading to downtime for repairs, which impacts the gathering and transportation schedule and the economic benefits of the enterprise. Regarding the issue of mechanical seal failure and damage in centrifugal pumps, Anhui Shengshi Datang analyzes it based on the operating principles of centrifugal pumps and derives the following preventive measures. 1. Implement Proper Seal Assembly Before assembling the mechanical seal, thorough preparations are essential. This includes inspecting the integrity and cleanliness of all assembly parts. Sealing components should be stored in a dust-free, dry environment to avoid contamination by dust and impurities. Simultaneously, necessary tools and materials should be prepared according to the technical specifications of the equipment manufacturer to ensure a smooth assembly process. The installation of the mechanical seal must strictly follow the installation manual and standards provided by the manufacturer. Before assembly, carefully read the relevant technical documentation to understand the seal's structure and working principle, and clarify the installation sequence and methods for each component. Any operation not performed according to the specified procedures may lead to seal failure. During the assembly of the mechanical seal, ensuring the alignment and concentricity of the stationary and rotating rings is crucial. Incorrect alignment can cause uneven contact on the sealing faces, leading to leakage. Special alignment tools can be used to ensure the seal components are on the same axis. Simultaneously, during assembly, check the pump shaft's diameter and concentricity to avoid wear caused by misalignment. When assembling the mechanical seal, it is essential to apply uniform installation pressure. Use specialized tools to apply torque gradually according to the manufacturer's recommended values, ensuring fasteners are evenly stressed. Excessive or insufficient pressure can lead to poor contact of the sealing faces, increasing wear risk and causing leakage. After completing the assembly, dynamic testing should be performed to verify the effectiveness of the mechanical seal. Through trial operation, observe for any leakage phenomena. During the testing process, operational parameters should be recorded to promptly identify and address potential issues. 2. Focus on Maintenance Management Regular inspection of the mechanical seal is the foundation for ensuring its normal operation. A detailed inspection plan should be established to conduct comprehensive checks on the mechanical seal periodically. Observe the flatness and smoothness of the sealing faces, and check for cracks, scratches, or other damage. Ensure the spring has good elasticity without deformation or fracture. Inspect the wear condition of the seal seat, pump shaft, and other related components to ensure their proper functioning. Cooling water is key to the normal operation of the mechanical seal, and its quality directly affects the seal's performance. Regularly test the chemical composition of the cooling water to ensure it is free from corrosive substances and solid impurities. Simultaneously, maintain the flow rate and temperature of the cooling water within appropriate ranges to effectively reduce the operating temperature of the sealing faces and prevent seal failure due to overheating. During the operation of the mechanical seal, proper lubrication is crucial for maintaining normal contact between the sealing faces. Regularly check and replace the lubricant according to the manufacturer's recommendations. The selection of lubricant should comply with the characteristics of the seal materials. Avoid using lubricants incompatible with the seal materials to prevent adverse effects on seal performance. Even under normal operating conditions, mechanical seals will eventually lose their sealing performance due to long-term wear. Therefore, a reasonable replacement cycle should be established to regularly replace severely worn seals, ensuring the normal operation of the equipment. When replacing seals, strictly follow the installation specifications to ensure the performance of the new seal meets requirements. 3. Enhance Maintenance Efforts Establishing a scientific and reasonable maintenance plan is the foundation for enhancing maintenance efforts. Based on the usage conditions, working environment, and historical failure records of the centrifugal pump, define the maintenance cycle, content, and personnel. Regular preventive maintenance can effectively prevent minor faults from escalating into major problems, ensuring the normal operation of the mechanical seal. After each maintenance, detailed maintenance records should be kept, including the maintenance date, content, issues found, actions taken, and parts replaced. These records not only provide a basis for subsequent maintenance but also help analyze the causes of failures and improve maintenance quality. Real-time monitoring of the operating parameters of the centrifugal pump allows for the timely detection of abnormalities. Using an online monitoring system can promptly issue alarms when seal abnormalities occur, preventing further escalation of faults. Through data analysis, factors affecting the performance of the mechanical seal can be identified, enabling the formulation of corresponding improvement measures. 4. Strengthen Personnel Management Defining the responsibilities of each position is the foundation of strengthening personnel management. Clear job description documents should be developed based on the operational and maintenance needs of the centrifugal pump. Each employee's work content, scope of responsibility, and assessment criteria should be clearly defined to ensure that all tasks during equipment maintenance and fault handling are assigned to specific individuals, forming a clear chain of responsibility. Conduct regular training sessions focused on centrifugal pumps and mechanical seals to enhance employees' professional skills and fault-handling capabilities. Training content should cover the structure, working principles, common failures and their handling methods, maintenance, and inspection procedures of mechanical seals. By disseminating professional knowledge, employees' awareness of the importance of mechanical seals is enhanced, improving the standardization and safety of their operations. Establish a scientific assessment mechanism to regularly evaluate employees' work performance. Assessment content should include technical proficiency, work attitude, fault-handling ability, and teamwork spirit. Through assessment, employees can be motivated to actively participate in the maintenance and management of mechanical seals, thereby improving overall work efficiency and quality. Welcome to purchase magnetic pumps and centrifugal pumps.  

  In the structure of a centrifugal pump, the mechanical seal is a core component, directly related to the stable operation and service life of the equipment. The primary function of the mechanical seal is to prevent fluid leakage from the pump, ensuring its normal operation and working efficiency. However, in practical applications, the mechanical seal of centrifugal pumps is often affected by factors such as operating conditions, medium characteristics, and operational maintenance, leading to failures. This results in seal damage, pump leakage, and even equipment shutdown, adversely impacting production safety and environmental protection. Failure of the centrifugal pump mechanical seal not only affects the equipment's performance and safety but also leads to high maintenance costs, increasing production expenses for oilfield enterprises. Therefore, researching the causes and damage mechanisms of mechanical seal failures in centrifugal pumps, and subsequently proposing effective prevention and improvement measures, is of significant importance for reducing the failure rate of mechanical seals and extending their service life. Anhui Shengshi Datang will give you an overview. 1. Analysis of Centrifugal Pump Operating Principle The operation of a centrifugal pump is based on Bernoulli's equation in fluid dynamics, which states that within a closed system, the energy of a fluid comprises kinetic energy, potential energy, and pressure energy, and these three forms of energy are converted within the pump. The core components of a centrifugal pump are the impeller and the pump casing. When the electric motor drives the pump shaft to rotate, the impeller rotates at high speed, causing the liquid inside the pump to also undergo rotational motion. Under the action of centrifugal force, the liquid is thrown from the center of the impeller towards its periphery, gaining an increase in both kinetic and pressure energy. This change in kinetic and pressure energy causes the liquid to flow out through the pump casing outlet. The pressure at the center of the impeller decreases, forming a low-pressure area, and liquid is continuously drawn into the pump under atmospheric pressure, thus forming a continuous liquid transport process. The operation of a centrifugal pump can be divided into three stages: liquid suction, acceleration, and discharge. In the suction stage, due to the low-pressure zone formed at the impeller center, external liquid flows into the pump under atmospheric pressure. In the acceleration stage, the liquid, acted upon by centrifugal force through the impeller, accelerates towards the pump casing. In the discharge stage, the high-speed liquid is gradually decelerated through the diffuser or volute, converting kinetic energy into pressure energy before being discharged from the pump. The main components of a centrifugal pump include the impeller, pump casing, pump shaft, mechanical seal, and bearings. The impeller, made of materials like cast iron, stainless steel, or plastic, is the core component. Its design directly determines the pump's flow rate and head. Parameters such as the impeller's shape, size, number of blades, and blade angle significantly affect liquid flow and pressure conversion efficiency. The pump casing, typically volute-shaped, contains the fluid. Its main functions are to collect liquid discharged from the impeller and guide it to the discharge outlet. The casing also facilitates energy conversion by gradually converting the liquid's kinetic energy into pressure energy through diffusion, thereby increasing the pump's head. The pump shaft, driven by the motor and connected to the impeller, transmits mechanical energy from the motor to the impeller, causing it to rotate. The pump shaft must possess high strength and stiffness to withstand centrifugal forces and the reaction forces of the liquid on the impeller. The mechanical seal prevents liquid leakage at the point where the pump shaft and casing interact. Its performance directly affects the pump's efficiency and safety. Bearings support and fix the pump shaft, reducing friction and vibration during rotation, ensuring stable pump operation. 2. Causes of Leakage in Centrifugal Pump Mechanical Seals (1) Trial Run Leakage.​ The installation precision of the mechanical seal directly affects its sealing effectiveness. If the seal faces are not accurately aligned during installation or if the face gap is set improperly, leakage can occur during trial operation. The stationary and rotating rings should be flat and aligned during installation. Failure to meet this standard can result in poor contact between the sealing faces, creating gaps and allowing medium leakage. Similarly, improper tightening according to design requirements or vibration during installation can cause misalignment of the seal rings, compromising the seal. During the trial run phase, the seal faces may not be fully bedded-in. Under high-speed operation and friction, face wear can lead to leakage. This wear is common if the seal faces have not been pre-treated or run-in, as initial high surface roughness increases frictional heat, exacerbating wear. Face wear reduces the contact integrity of the sealing surfaces, leading to leakage. Additionally, excessively rapid temperature rise during trial runs can cause uneven thermal expansion of the faces, accelerating wear. Vibration generated during pump operation due to bearing wear, imbalance, or other mechanical issues can affect the mechanical seal, which is sensitive to vibration. Vibration causes uneven pressure distribution between the seal faces, potentially leading to misalignment of the rotating and stationary rings, seal failure, and leakage. Particularly during trial runs, excessive axial shaft movement or radial runout beyond standards can adversely affect the stability of the seal components. (2) Static Test Leakage.​ In mechanical seals, auxiliary sealing elements are typically made of materials like rubber or PTFE. The elasticity and corrosion resistance of these materials significantly impact sealing performance. Improper material selection for auxiliary seals can lead to leakage during static pressure testing. If the seal material lacks corrosion resistance or temperature tolerance, it may deform under static test pressure or temperature, failing to provide an effective seal. Simultaneously, aging, hardening, or loss of elasticity due to temperature changes can prevent the seal faces from fitting tightly, causing leakage. During static testing, pressure within the seal chamber should not fluctuate significantly. Otherwise, uneven pressure on the seal faces may cause leakage. Static tests are usually conducted at slightly higher pressures than operating pressure to verify seal integrity. However, if the pressure is too high or applied unevenly, the seal components can be damaged, compromising the contact between the stationary and rotating rings and causing leakage. Especially during static tests, if the liquid temperature is high, thermal expansion within the seal chamber can cause pressure fluctuations, leading to inadequate sealing. The seal faces, often made of wear-resistant, high-strength materials like silicon carbide or ceramic, are critical. If subjected to excessive pressure during installation or static testing, minor deformation can occur, affecting the faces' ability to mate properly. (3) Operational Leakage.​ The operating conditions of a centrifugal pump may change with its working state. Variations in fluid temperature, pressure, or flow rate can all affect seal performance. When operating conditions exceed the seal's design limits—such as excessively high temperature or pressure—the material properties of the seal components can degrade, leading to seal failure. Leakage is particularly likely during transient flow fluctuations or under highly variable load conditions. Mechanical seals often rely on the presence of a seal fluid for adequate lubrication and cooling. Insufficient seal fluid flow or excessively high temperature can cause the seal fluid to evaporate or vaporize, reducing sealing effectiveness. Furthermore, impurities or contaminants in the seal fluid can enter the seal chamber, impairing lubrication between the seal faces, accelerating wear, and causing leakage. The material selection and design of the mechanical seal are directly related to its performance. If the seal material has insufficient corrosion resistance, it may corrode when exposed to the pump fluid, leading to decreased sealing performance. Similarly, poor design can cause uneven force distribution on the seal faces or issues related to thermal expansion, resulting in seal failure. Therefore, appropriate material selection and sound design are crucial factors for ensuring the stability of the mechanical seal during normal operation. (4) Cooling Water Quality.​ The role of cooling water is to ensure temperature control for the mechanical seal, preventing seal failure due to high temperatures. If the cooling water quality does not meet standards, it can lead to mechanical seal leakage. If the cooling water contains impurities, solid particles, oil contamination, or other pollutants, it can negatively impact the working environment of the mechanical seal. These impurities may enter the seal chamber, causing wear on the stationary and rotating rings, reducing the smoothness of the seal faces, and thus inducing leakage. Simultaneously, the presence of pollutants can obstruct the flow of cooling water, preventing it from effectively carrying away the heat generated at the seal faces, further exacerbating wear and temperature rise. The chemical composition of the cooling water can also affect the materials of the mechanical seal. Cooling water containing high concentrations of corrosive agents can accelerate the corrosion of seal materials, reducing their service life. If the materials used in the mechanical seal are not corrosion-resistant, prolonged exposure to such cooling water can lead to cracks, pitting, or spalling on the seal faces, ultimately causing leakage. The temperature of the cooling water is crucial for the performance of the mechanical seal. If the cooling water temperature is too high, it may cause softening or aging of the seal materials, reducing their elasticity and sealing effectiveness. As temperature increases, the seal components may not maintain the designed tight contact, leading to leakage.

The horizontal multistage centrifugal pump is a type of fluid machinery primarily used for liquid transportation. It features high delivery efficiency and can be applied to the transfer of crude oil and chemical products, intermediate process liquids, cooling and circulation systems, as well as waste treatment and discharge. A petrochemical plant typically operates thousands of horizontal multistage centrifugal pumps. Prolonged operation inevitably leads to wear and technical failures, which can reduce operating efficiency and increase both production costs and the risk of shutdowns for maintenance. Currently, the petroleum industry generally adopts the DG-2499Y horizontal multistage centrifugal pump. Anhui Shengshi Datang will conduct an in-depth analysis of its technical parameters, explore possible causes of technical failure, and propose targeted maintenance recommendations to provide a systematic repair plan, ensuring equipment stability and continuous plant operation.    Technical Parameters The horizontal multistage centrifugal pump consists of multiple pump stages connected in series, with each stage including an impeller and a corresponding diffuser. In each stage, the liquid gains kinetic energy through the impeller, which is then partially converted into pressure energy in the diffuser—thus progressively increasing the total output pressure of the pump. This pump features a compact structure, ease of maintenance, and high efficiency in handling large flow rates, meeting high head requirements. Its rated flow ranges from 6 to 1000 m³/h, with a rated head between 40 and 2000 m. Operating speeds include 3500 r/min, 2900 r/min, 1750 r/min, and 1450 r/min, with a working frequency of 50 Hz or 60 Hz. Taking the DG-2499Y horizontal multistage centrifugal pump as an example, its key technical features include:  a. Two bearings installed on the front and rear shafts.  b. The pump and motor are connected by an elastic pin coupling, with the motor rotating clockwise during operation.  c. The suction inlet is set horizontally, while the discharge outlet is vertical.  d. Bearings are lubricated with grease, and the shaft seal can be either a packing seal or a mechanical seal.    Failure Cause Analysis A. Dry Running Without Lubrication Dry running occurs when the pump operates without sufficient lubrication due to failure or absence of lubricant. For the DG-2499Y pump, the bearings and shaft sleeves rely on lubrication to minimize friction and wear. Without lubrication, these parts can quickly wear out due to high friction and heat. The packing seal’s effectiveness may also decrease, leading to shaft seal failure and leakage. Excessive bearing wear can cause instability, resulting in impeller imbalance, increased vibration and noise, and reduced efficiency and lifespan. In extreme cases, complete bearing failure may occur, causing severe mechanical damage and shutdown. B. Chemical Corrosion In petrochemical applications, the DG-2499Y pump often handles chemically aggressive media such as crude oil, intermediate refinery products, and other chemical process fluids. These media may contain corrosive compounds such as sulfides, acids, and alkalis, which can attack metal components like impellers, shafts, and sleeves. Prolonged exposure leads to structural weakening, cracking, or pitting corrosion. Factors such as temperature, concentration, and flow velocity significantly affect corrosion rate. For instance, high temperatures accelerate corrosion, while high velocities can cause erosion–corrosion, where chemical attack and mechanical wear act simultaneously. Chemical reactions may also deteriorate packing and seal materials, reducing sealing performance and causing leakage or pump failure. C. Overheating During Operation During long-term operation, friction, poor heat dissipation, or high process fluid temperature may lead to overheating. Bearing overheating is common, often caused by insufficient or poor-quality lubricant. Under high-speed rotation, frictional heat between shaft sleeves can degrade material properties. Impellers and sealing rings may lose mechanical strength at elevated temperatures, reducing pump efficiency or causing structural damage. Insufficient flow in the recirculation or discharge lines can also lead to overheating, resulting in component fatigue, accelerated wear, and reduced service life. D. Solid Particle Contamination In petrochemical operations, pumps may be damaged by solid impurities in the conveyed medium—such as unreacted catalyst particles, sediments, corrosion products, or small debris. When these enter the pump, especially through the suction section and impeller, they increase wear on these components and reduce efficiency. Continuous particle erosion can severely wear sealing rings, shafts, and sleeves, leading to seal failure and performance degradation. E. Cavitation Cavitation occurs when the pressure at the suction side drops to or below the liquid’s vapor pressure, forming vapor bubbles that collapse in high-pressure regions. The resulting shock waves damage impellers and internal components. This phenomenon is common in petrochemical applications where volatile solvents or gases are present, especially under high-temperature or low-pressure conditions.    Key Maintenance Techniques A. Zero-Flow Issue After Startup  a. When a DG-2499Y pump exhibits zero flow after startup, technicians should perform precise diagnostics:  b. Use pressure testing instruments to verify system sealing, ensuring no gas or liquid leakage, especially at the shaft seal and packing areas.   c. Monitor flow and pressure readings to identify internal blockages or piping faults.   d. Check motor-pump alignment to ensure efficient power transmission through the coupling.  e. Use infrared thermography to detect heat concentration indicating friction hotspots.  f. Replace or repair faulty components (e.g., impellers, bearings) and realign using laser tools.  g. Ensure all maintenance steps meet petrochemical safety and technical standards for stable operation. B. Flow Rate Troubleshooting  a. Flow issues often result from chemical corrosion, solid contamination, or cavitation. Maintenance should include:  b. Evaluating the pump’s Q–H (flow–head) curve to determine deviations.  c. Cleaning or replacing worn or fouled impellers.  d. Inspecting and replacing worn sealing rings and bearings.  e. Measuring actual vs. theoretical flow using flowmeters and adjusting inlet valves as needed.  f. Checking for cavitation and optimizing NPSH (Net Positive Suction Head) conditions to prevent vapor ingestion.  g. Detecting blockages or leaks in the pipeline with ultrasonic flow and pressure sensors and repairing as required. C. Overload in the Drive System  a. To resolve motor or drive overload:  b. Conduct full performance tests using instruments like clamp ammeters and power analyzers to ensure operation within rated limits.  c. Inspect impellers, bearings, and seals for wear or damage that may increase load.  d. Remove internal blockages and ensure smooth fluid flow.  e. Precisely align the pump and motor to reduce mechanical transmission losses. D. Bearing Overheating  a. Maintenance steps include:  b. Using vibration analyzers to detect abnormal bearing vibration—an early sign of overheating.  c. Regularly monitoring bearing temperature via infrared thermography; disassemble and replace damaged bearings when necessary.  d. Inspecting and cleaning the lubrication and cooling systems to ensure proper lubricant flow and quality.  e. Verifying correct bearing installation and alignment to minimize frictional heat. E. Vibration Troubleshooting  a. Pump vibration may result from impeller blockage or imbalance, misalignment, or loose components. Maintenance personnel should:  b. Use vibration and laser alignment tools to diagnose misalignment.  c. Adjust bearing preload to prevent overheating and vibration.  d. Inspect impellers for damage or imbalance and perform dynamic balancing if necessary.  e. Tighten all fasteners, including shaft sleeve nuts and bolts, to ensure structural stability and safe operation.

Welcome everyone to join Anhui Shengshi Datang in learning about submersible pumps.  Common Faults of Submersible Pumps 1. Electric Leakage Electric leakage is one of the most common and dangerous faults in submersible pumps, as it poses a serious threat to human safety. When the switch is turned on, the leakage protection device in the transformer distribution room may automatically trip. Without such protection, the motor could burn out. Water entering the pump body lowers the insulation resistance of the submersible pump. Long-term use can cause wear on the sealing surfaces, allowing water to seep in and create leakage. Once leakage occurs, the motor should be removed and dried in an oven or with a 100–200 Ω lamp. Afterward, replace the mechanical seal, reassemble the pump, and then it can be safely operated again. 2. Oil Leakage Oil leakage in a submersible pump is mainly caused by severe wear or poor sealing of the oil seal box. When oil leakage occurs, oil stains can often be seen near the water inlet. Remove the screws at the inlet and carefully inspect the oil chamber for water intrusion. If water is found inside, it indicates poor sealing and the oil seal box should be replaced immediately to prevent water from entering the oil chamber and damaging the motor. If oil stains appear around the cable connection, the leakage is likely from inside the motor, possibly due to a cracked joint or substandard lead wire. After identifying the cause, replace the defective parts and check the motor’s insulation. If the insulation is compromised, replace the oil inside the motor with fresh oil. 3. Impeller Does Not Rotate After Power-On If the pump emits an AC humming sound when powered on but the impeller does not rotate, cut off the power and try to manually rotate the impeller. If it does not move, it is jammed and the pump must be disassembled for inspection. If the impeller moves freely but still does not rotate when powered, the likely cause is worn bearings. The magnetic field generated by the stator may attract the rotor, preventing it from turning. When reassembling the pump, ensure the impeller rotates freely to eliminate this issue. 4. Low Water Output After removing the rotor, check whether it rotates smoothly. When dismantling the pump, inspect for looseness between the lower part of the pump and the bearing. If the rotor has dropped, it means the rotor’s rotational force is reduced, resulting in decreased power output. Place an appropriate washer between the bearing and the rotor, reassemble the pump, and perform a test run to gradually identify and resolve the fault.    Submersible Pump Maintenance 1. Correct Assembly and Disassembly Methods Before disassembly, mark the joint between the end cover and the base to ensure proper alignment during reassembly and avoid shaft misalignment. After removing the impeller, use the heat expansion and cold contraction method — heating and lightly tapping to detach it. During disassembly, carefully inspect the winding for damage and analyze the cause. When removing damaged windings, protect the iron core and plastic insulating rings to prevent damage to insulation or electromagnetic components. Always use proper tools and techniques to avoid harming other parts.  2. Analysis of Winding Burnout Causes During motor disassembly, avoid moving the assembly excessively to prevent grounding or short circuits when installing new windings. When rewinding, always use wires from reliable manufacturers to ensure quality. For low-insulation areas, use insulation materials of sufficient thickness and ensure padding is properly installed. Do not use sharp tools to scrape the wires during winding, as this may damage insulation. 3. Proper Waterproof Insulation of Cable Joints At the joint, remove the sheath and insulation layer, and clean any oxidation from the copper wire surface. Wrap the connection securely with polyester adhesive tape to form a mechanical protective layer and ensure waterproof insulation.  4. Preparations Before Powering On Before energizing the motor, fill it with clean water to help cool the windings and provide lubrication. Operating the motor without water can cause severe damage. In winter, be sure to drain the water from the motor to prevent freezing and cracking. 5. Correct Application of Insulating Varnish to Motor Coils After forming the stator, immerse it completely in insulating varnish for about 30 minutes before removing it. Then brush varnish evenly on the surface. Since varnish has high viscosity and poor penetration, brushing alone may not provide a uniform coating or meet required insulation quality standards.    Proper Maintenance Practices Proper maintenance is crucial for extending the service life and efficiency of submersible pumps. If the pump will not be used for an extended period, it should be removed from the well and all components should be inspected to prevent rusting. For pumps with long service history, disassemble and clean all internal parts, including removing screws and flushing sediment from the impeller. Severely worn components should be replaced promptly. If rust is found, clean the affected areas, apply oil, and reassemble. Always check the sealing parts. Store electric pumps in a dry, well-ventilated place to prevent moisture damage. Add lubricating oil periodically, using low-viscosity, water-insoluble oil.   Avoid long-term overload operation or pumping water containing large amounts of sediment. When the pump runs dry, limit the duration to prevent motor overheating and burnout. During operation, the operator should continuously monitor the working voltage and water flow. If either exceeds the specified range, the motor should be stopped immediately to prevent damage.  

Regarding some questions about screw pumps, Anhui Shengshi Datang would like to share some insights with everyone.   Causes and Hazards Analysis of Rod String Reverse Rotation in Screw Pump Wells 1. Analysis of Causes for Rod String Reverse Rotation in Screw Pump Wells During oilfield extraction using Screw Pumps, reverse rotation of the rod string is a relatively common failure. The causes of this reverse rotation are complex, but the primary reason is the sudden shutdown or sticking of the pump during operation, which causes deformation and torsion of the rod string. The rapid release of this deformation and torsion then leads to reverse rotation. Specifically, if the Screw Pump suddenly stops or sticks during operation, a pressure difference arises between the high-pressure liquid retained in the production tubing and the wellbore hydrostatic pressure in the casing annulus. Driven by this pressure difference, the Screw Pump acts as a hydraulic motor, driving the rotor and the connected rod string to rotate rapidly in reverse. The reverse rotation of the Screw Pump rod string is influenced by the tubing-casing pressure difference, exhibiting variations in reverse rotation duration and speed. Generally, a larger tubing-casing pressure difference results in faster reverse rotation speed and longer duration for the rod string. As the pressure difference gradually decreases, the reverse rotation speed and duration correspondingly decrease until the pressure difference balances, at which point the reverse rotation gradually ceases. When reverse rotation occurs, the rod string vibrates intensely. If resonance occurs during this vibration—meaning the vibration frequency of the reversing rod string synchronizes with the natural frequency of the wellhead—the rotation speed can instantly surge to its maximum. This situation can trigger serious safety accidents, cause significant harm to the worksite, and even result in casualties. 2. Hazards of Rod String Reverse Rotation in Screw Pump Wells The hazards caused by rod string reverse rotation vary in degree depending on the speed and duration of the reversal. Severe cases can lead to onsite safety incidents with serious consequences. Specifically, the hazards mainly manifest in the following three aspects: (1) Reverse rotation can cause the rod string to become displaced from its original position, leading to the swinging of the Screw Pump polish rod. This can cause significant wear and tear on the Screw Pump equipment, damaging various components and parts. (2) During reverse rotation, if the speed is too high or the duration too long, the temperature of the reversing components can continuously rise, potentially igniting flammable gases at the wellhead. This could trigger an explosion at the worksite, leading to unforeseeable serious consequences. (3) If reverse rotation is not effectively controlled, it can cause the drive pulley to shatter. Fragments of the pulley flying around the worksite pose a risk of injury to personnel, damage the oilfield production site, reduce extraction efficiency, and increase the probability of various safety incidents.   Commonly Used Anti-Reverse Rotation Devices for Screw Pump Well Rod Strings 1. Ratchet and Pawl Type Anti-Reverse Device This type of device prevents reverse rotation by utilizing the one-way engagement of a ratchet and pawl. Specifically, the ratchet and pawl engage via an external meshing configuration. When the Screw Pump drive operates normally, centrifugal force causes the pawl to disengage from the ratchet brake band, so the anti-reverse device remains inactive. However, when the Screw Pump suddenly stops during operation, the rod string begins to reverse due to inertia. During this reverse rotation, gravity and spring force cause the pawl to engage with the ratchet brake band, activating the anti-reverse device. The device then dissipates the torque generated by the high-speed reverse rotation through frictional force. The ratchet and pawl device has a simple structure, is easy to install, has a low overall cost, and offers good flexibility and controllability. However, it typically requires manual intervention at close range for activation/operation. Improper operation can cause the friction surfaces to slip, presenting a safety risk. Additionally, this type of device can generate significant noise during operation and subjects the components to considerable impact and wear, necessitating frequent part replacements. 2. Friction Type Anti-Reverse Device The friction type anti-reverse device consists of two main parts: an overrunning clutch that identifies rotation direction and a brake shoe assembly. In this device, the brake shoes are connected to the brake bodies via riveting, and the two brake bodies grip the outer ring. During normal Screw Pump operation (clockwise rotation), the device remains inactive. When a sudden shutdown causes reverse rotation, the drive mechanism reverses. In this state, rollers move between the star wheel and the outer ring, activating the device. The resulting damping effect restricts the rotation of the star wheel, thereby achieving the anti-reverse function. However, since the operation of this device often requires manual control, improper handling can lead to failure. Furthermore, replacing this device involves significant safety risks. Consequently, its application in Screw Pump wells is currently relatively limited. 3. Sprag Type Anti-Reverse Device The sprag type anti-reverse device operates based on the principle of an overrunning clutch. Specifically, during normal Screw Pump operation (forward rod string rotation), the sprags inside the device align normally and remain disengaged from the outer ring, keeping the device inactive. When the pump suddenly stops and the rod string starts to reverse rotate, the resulting reverse torque causes the device to rotate in the opposite direction. This makes the sprags align in the reverse direction, locking them against the outer ring and preventing reverse rotation of the rod string. The sprag type device has a simple construction, is easy to install, offers good controllability, and operates with high safety, minimizing the risk of accidents. It also has a long service life and does not require frequent part replacements. The drawback is that it cannot fundamentally solve the reverse rotation problem. If the reverse torque exceeds the capacity the sprags can withstand, it can cause sprag failure and device malfunction. Additionally, daily maintenance of this device can be inconvenient. 4. Hydraulic Type Anti-Reverse Device The working principle of the hydraulic anti-reverse device is somewhat similar to a car's braking system. When the Screw Pump suddenly stops and the rod string is about to reverse rotate, the hydraulic motor within the device activates. Hydraulic fluid pressure drives friction pads against a brake disc, releasing a large amount of the reverse rotation potential energy, thereby dissipating the reverse rotation of the rod string. The advantages of the hydraulic type device include stable and reliable operation, high safety, no noise generation, and no hazard to onsite personnel. Maintenance, replacement, and daily upkeep are relatively convenient and safe. This type of device can more thoroughly address the reverse rotation problem, enhancing the operational safety of the Screw Pump system. The disadvantages are its high overall cost and stringent quality requirements for the hydraulic components, leading to potentially higher maintenance and replacement costs. If issues like hydraulic fluid degradation or leaks occur during operation, the device's performance can be affected, necessitating regular maintenance.   Measures to Address Rod String Reverse Rotation in Screw Pump Wells 1. Research and Application of Safer, More Reliable Anti-Reverse Devices Analysis of the causes of rod string reverse rotation indicates that the main factors are the release of stored elastic potential energy in the rod string and the effect of the tubing-casing pressure difference. If reverse rotation is not effectively controlled, especially at high speeds or for prolonged durations, it can lead to a series of severe consequences and safety incidents, posing significant risks. Therefore, technical research and application should be strengthened. Based on existing anti-reverse devices, upgrades and improvements should be made to develop and apply safer and more reliable devices. These should ensure the safe release of torque and effective elimination of the pressure difference during sudden Screw Pump shutdowns, reducing associated safety risks. The working principles, advantages, and disadvantages of common anti-reverse devices need in-depth analysis for targeted improvements. This will enhance the stability and reliability of these devices, minimize safety risks during use, and maximize the operational safety of Screw Pump equipment. 2. Application of Downhole Anti-Backflow Switches Using downhole anti-backflow switches can effectively address reverse rotation caused by hydraulic forces. The downhole anti-backflow switch consists of components like a disc, ball, push rod, shear pin, and crossover sub. Its application in the Screw Pump drive system can reduce the torque generated during sudden shutdowns, lower the reverse rotation speed, and mitigate reverse rotation caused by the tubing-casing pressure difference. By dissipating hydraulic forces, it helps control reverse rotation and also prevents rod string back-off. The anti-backflow switch has a simple structure, low cost, and is easy to install. It has been widely used in oilfield development due to its strong stability, high reliability, and broad application prospects. 3. Strengthening Surface Safety Management To effectively control reverse rotation, it is essential not only to equip Screw Pump systems with appropriate anti-reverse devices but also to enhance safety management in surface operations and implement protective measures to reduce the adverse consequences of reverse rotation. Specific measures include: ① Personnel should perform daily inspection, maintenance, and servicing of Screw Pump equipment, maintain proper equipment management records, continuously accumulate experience, and improve safety prevention capabilities. ② Implement continuous monitoring of the Screw Pump system's operation to promptly detect abnormalities. Take immediate action for fault diagnosis and troubleshooting to reduce the probability of reverse rotation occurrences. ③ Establish comprehensive emergency response plans. For sudden reverse rotation events, immediately activate the emergency plan to lower the probability of safety incidents.

In the previous blog, we discussed the common failures of pneumatic diaphragm pumps and analyzed their causes. Now, Anhui Shengshi Datang will guide you on how to troubleshoot these issues and what steps to take when encountering such situations. Troubleshooting and Handling Measures 1. Air Pump Not Working When it is found that the pneumatic diaphragm pump cannot start normally or stops immediately after starting, it should be inspected based on this symptom: (1) First, check whether the connection points of the circuit are broken. If the circuit is damaged or the connections are loose, replace the wires in the circuit or reinforce the connections promptly to restore the equipment to operation and improve the stability of the air pump. (2) If parts that frequently experience friction show significant wear or have aged and lost elasticity, consider replacing them to enhance the stability of the system operation. 2. Inlet/Outlet Pipeline Blockage If the issue with the air pump is determined to be in the inlet/outlet pipeline, and the pump cannot operate normally due to pipeline blockage, inspect and address it based on the following symptoms: Common Faults Cause Analysis Handling Measures Insufficient pressure supply or pressure increase in the diaphragm pump Improper adjustment of the pneumatic diaphragm pump pressure regulating valve or poor air quality; malfunction of the pressure regulating valve; malfunction of the pressure gauge Adjust the pressure valve to the required pressure; inspect and repair the pressure regulating valve; inspect or replace the pressure gauge Pressure drop in the diaphragm pump Insufficient oil replenishment by the oil replenishment valve; insufficient feed or leakage in the feed valve; oil leakage from the plunger seal Repair the oil replenishment valve; inspect and repair the sealing parts; refill with new oil Reduced flow rate in the diaphragm pump Pump body leakage or diaphragm damage; rupture of the inlet/outlet valve; diaphragm damage; low speed that cannot be adjusted Inspect and replace the sealing gasket or diaphragm; inspect, repair, or replace the feed valve; replace the diaphragm; inspect and repair the control device, adjust the rotation speed (1) Disassemble and clean the internal pipelines of the equipment to remove various impurities attached to the pipelines. Improve the cleanliness of the pipe walls and enhance the stability of the equipment operation. (2) Strengthen the management of medium materials to ensure that materials do not mix due to sharing. Ideally, use one device for pumping a specific material. If the same equipment must be used, clean the pipelines promptly to avoid air pump pipeline blockages and improve the stability of the air pump's working condition. 3. Severe Ball Seat Wear If ball seat wear is confirmed through inspection, troubleshoot using the following measures: (1) First, confirm whether its sealing performance can support normal equipment operation. If the ball seat wear is too severe to determine, replace the ball seat to maintain the fit between the ball seat and the ball and avoid poor sealing. (2) Since friction between the ball seat and the ball is inevitable, monitor the operating condition of the ball seat in real time during daily operations to enhance the overall stability of the equipment. 4. Severe Ball Valve Wear If ball valve wear is confirmed through inspection, and the wear is severe, troubleshoot using the following measures: (1) Replace severely damaged ball valves. If no spare ball valve is available, temporarily use a ball bearing as a substitute and replace it with a matching ball valve afterward. (2) Media with excessively high viscosity will increase the resistance of the ball, preventing flexible operation. In this case, clean the ball valve and base to ensure smooth transportation and improve the stability of the equipment operation. 5. Irregular Air Pump Operation For issues related to irregular air pump operation, inspect and address them based on the specific symptoms: (1) Replace severely worn ball valves to improve structural stability. (2) If the diaphragm is damaged, replace it promptly to enhance the reliability of the system's processing. (3) If the issue is due to limitations of the preset system, upgrade the system to improve the stability of the equipment system operation. 6. Insufficient Air Supply Pressure For problems caused by insufficient air supply pressure, inspect and troubleshoot using the following measures: (1) Confirm whether the equipment operating system is stable and check the system pressure condition. If it meets the requirements, continue using it; otherwise, debug it as soon as possible. (2) To maintain the volume and cleanliness of compressed air, add an air filtration device and improve the purity of the compressed air to maintain the equipment output rate and enhance system stability.  

Anhui Shengshi Datang Pump Industry is committed to providing customers with the best technology and services, always putting customers at the core.   Introduction to Pneumatic Diaphragm Pumps A pneumatic diaphragm pump uses compressed air as its driving power source. It typically consists of components such as an air inlet, air distribution valve, balls, ball seats, diaphragms, connecting rods, central bracket, pump inlet, and exhaust outlet. Once it receives a control command, the pump starts operating by utilizing air pressure and its special internal structure to transfer materials. It has low requirements for the properties of the conveyed medium and can handle a wide range of substances, including solid–liquid mixtures, corrosive acid and alkali liquids, volatile, flammable, and toxic fluids, as well as viscous materials. It offers high working efficiency and simple operation. However, due to aging parts or improper use, diaphragm pump failures may occur during operation. A. Materials Pneumatic diaphragm pumps are commonly made from four materials: aluminum alloy, engineering plastics, cast alloy, and stainless steel. Depending on the medium being handled, the pump materials can be adjusted accordingly to meet the diverse needs of users. Owing to its adaptability to different environments, the pump can handle materials that conventional pumps cannot, earning it wide recognition among users. B. Working Principle The diaphragm pump operates by using a power source to drive the piston, which in turn moves hydraulic oil back and forth to push the diaphragm, thereby achieving suction and discharge of liquids. When the piston moves backward, the change in air pressure causes the diaphragm to deform and concave outward, increasing the chamber volume and decreasing pressure. When the chamber pressure drops below the inlet pressure, the inlet valve opens, allowing fluid to flow into the diaphragm chamber. Once the piston reaches its limit, the chamber volume is at its maximum and the pressure is at its minimum. After the inlet valve closes, the suction process is complete, and liquid filling is achieved. As the piston moves forward, the diaphragm gradually bulges outward, decreasing the chamber volume and increasing internal pressure. When the pressure in the chamber exceeds the resistance of the outlet valve, the liquid is expelled. Once the piston reaches the external limit, the outlet valve closes under gravity and spring force, completing the discharge process. The diaphragm pump then proceeds to the next suction and discharge cycle. Through continuous reciprocation, the diaphragm pump effectively transfers the liquid. C. Characteristics 1. Low heat generation: Powered by compressed air, the exhaust process involves air expansion, which absorbs heat, reducing the operating temperature. Since no harmful gases are emitted, the air properties remain unchanged. 2. No spark generation: As it does not rely on electricity, static charges are safely discharged to the ground, preventing spark formation. 3. Can handle solid particles: Due to its positive displacement working principle, there is no backflow or clogging. 4. No impact on material properties: The pump merely transfers fluids and does not alter their structure, making it suitable for handling chemically unstable substances. 5. Controllable flow rate: By adding a throttling valve at the outlet, the flow rate can be easily adjusted. 6. Self-priming capability. 7. Safe dry running: The pump can operate without load without damage. 8. Submersible operation: It can work underwater if needed. 9. Wide range of transferable liquids: From water-like fluids to highly viscous substances. 10. Simple system and easy operation: No cables or fuses are required. 11. Compact and portable: Lightweight and easy to move. 12. Maintenance-free operation: No lubrication needed, eliminating leakage and environmental pollution. 13. Stable performance: Efficiency does not decline due to wear.   Common Failures and Causes Although pneumatic diaphragm pumps are compact and occupy little space, their internal structure is complex, with many interconnected components. Failure of any single part can lead to operational problems. Unusual noise, fluid leakage, or control valve malfunctions are typical warning signs. Timely maintenance is essential. Component wear and aging caused by friction are also major sources of malfunction. A. Pump Not Operating 1. Symptoms: When starting, the pump either does not respond or stops running shortly after starting. 2. Causes: a. Circuit issues such as disconnection or short circuit prevent proper operation. b. Severe component damage — for example, worn ball valves or damaged air valves — leads to loss of pressure and system shutdown. B. Blocked Inlet or Outlet Pipeline 1. Symptoms: Reduced working pressure, weak suction, and slow fluid transfer. 2. Causes: a. High-viscosity materials adhere to the inner pipe walls, reducing diameter and smoothness, increasing resistance. b. Use of multiple materials without thorough cleaning causes chemical reactions between residues, affecting normal operation. C. Severe Ball Seat Wear Continuous friction wears down the surface of the ball seat, creating gaps between the ball and seat. This may cause air leakage and reduced pump output. D. Severe Ball Valve Wear 1. Symptoms: Irregular ball shape, visible surface pitting, or heavy corrosion reducing ball diameter. 2. Causes: a. Manufacturing inconsistencies cause mismatch between the ball and seat. b. Long-term operation under friction and corrosive environments accelerates valve damage. E. Irregular Pump Operation 1. Symptoms: The pump fails to complete normal suction and discharge cycles even after adjustment. 2. Causes: a. Worn or damaged ball valve. b. Aged or broken diaphragm. c. Incorrect system settings. F. Insufficient Air Supply Pressure or Poor Air Quality Insufficient air pressure leads to reduced gas volume entering the air chamber, resulting in inadequate force to drive the connecting rod reciprocation. Increasing air pressure typically resolves this issue. Additionally, poor air quality can hinder the movement of the linkage rod and reduce motor speed, weakening pump output.