The diaphragm pump is driven by a variable-frequency motor. If the startup and shutdown loads are too large or too small, the load fluctuation is large in a short time, and the pump operates under low load for a long time, the inverter will be affected. To avoid the above situations, it is hard to control the startup and shutdown loads at about 30%, and it is set in the instrument so that the load increase and decrease can be completed within a period of time, which effectively achieves the maintenance of the inverter from the process.

Pressure system operation

The instrument air and lubricating oil pressure of the diaphragm pump are interlocked with the main motor. The oil injection and discharge valves of the propulsion fluid are air closed valves, and a certain air pressure must be maintained at all times. The minimum operating pressure of the two valves is not less than 0.4 MPa. Therefore, the instrument air pressure is generally maintained above 0.15 MPa. The instrument air is not stopped even after the pump is stopped, so as to avoid insufficient or excessive liquid in the propulsion fluid chamber, and the air supplied to the valve is filtered and oil atomized.

During the operation of the diaphragm pump, the lubricating oil pressure should not be lower than the pressure interlock value (0.15 MPa), and the differential pressure of the lubricating oil outlet filter should not be too large. The steel ball in the lubricating oil flow camera should be at the upper limit. The adjustment range should not be too large when adjusting this flow, so as to avoid the interlocking trip caused by too fast pressure drop due to too large instantaneous flow.

Through the above process improvement and the proficiency in the key points of operation, the diaphragm pump has always had a stable process environment during operation. In the past more than a year of operation, there was only one trip due to electrical reasons, achieving a long cycle, safe and efficient operation.