Air Operated Diaphragm Pump Discharge Pressure

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.