Operating procedures for electric diaphragm pumps

Original poster, please make more use of the forum’s search function. By simply waiting for others to paste those long passages below, you might miss an opportunity to learn on your own.

The moderator’s reminder is correct; I’ve been searching as well, and by browsing I’ve learned a lot of knowledge. However, there really isn’t much information available regarding the operating procedures and precautions for these two types of pumps, so I had to seek help. I hope to get assistance from everyone.

Operating Procedures for Diaphragm Metering Pumps I. Preparations before Startup 1. Check whether the quality and quantity of oil inside the pump meet the requirements (in the drive gearbox, it should be at the midpoint indicated by the oil level gauge; in the three-valve oil reservoirs and the diaphragm chamber, the oil level must not drop below the red indicator line)； 　　2. Check whether the welds on the inlet and outlet pipelines, the bolts at the connections, and the sealing surfaces are in good condition; also check whether the suction and discharge pipes of the pump are unobstructed ； 　　3. Before starting a pump for the first time, turn the coupling several times to ensure there is no sticking; check that the rotation direction of the motor at the control station matches that of the shut-off valve on the pump. 　　4. Run the pump under adaptive conditions; especially when it has been shut down for more than 5 days, it must be started from the \"0\" position. (For short-term shutdowns, it can be started from any position.) After running without load for 5 minutes, adjust the piston stroke to the desired position before starting it under load ； 　　5. Pressurized operation: Close the vent valve in the oil cup of the diaphragm pump’s three valves, and gradually increase the pressure to the rated value. 　　II. Normal Operation 　　1. During normal operation, the seal area of the plunger should not feel hot to the touch, there should be no leakage, and the oil temperature inside the transmission box must not exceed 65°C. 　　2. Regularly check whether the oil level and quality in the oil cups of the three valves meet the requirements, and observe whether there are any fluctuations in the oil level; if fluctuations are detected, it indicates that the valves are leaking. 　　3. After the safety valve has been adjusted, it is strictly prohibited to turn the adjustment screw, and it is also strictly prohibited to touch the oil filler valve ball; keep the oil in the oil cups of the three valves clean. 　　4. Regularly check the temperature of the feed liquid (generally ≤1000°C) and the pressure of the liquid exiting the pump (≤rated pressure). 　　III. Parking and Other Operations 　　1. First, adjust the adjustment mechanism to the “0” position; the crankshaft stops rotating, but the motor continues to operate. 　　When it is running, then the power is cut off, and the motor stops rotating. 　　2. If the pump is to be shut down for an extended period of time, the liquid inside the pump must be completely drained to prevent blockage and corrosion of the pump. 　　3. 20# or 30# mechanical oil is generally used in the gearbox; the oil level in the gearbox and the three-valve oil cups should be maintained at the specified level. 　　4. The lubricating oil in the pump should be replaced every 6 months. When replacing it, the old oil must be completely removed; only after the tank is thoroughly cleaned should new oil be poured in. 　　5. Keep the exterior of the equipment clean and ensure good insulation of the motor. 　　6. Keep records of equipment operation, shutdown, accidents, and maintenance.

They all belong to positive displacement pumps; special attention should be paid during operation: 1. When starting the pump, open the inlet and outlet first, then start the motor. 2. When stopping the pump, turn off the motor first, and then close the inlet and outlet. This is different from centrifugal pumps, and care must be taken; otherwise, pressure buildup may occur