Seeking help with diaphragm metering pumps
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Dear experts, please explain the working principle of diaphragm metering pumps, their structure, as well as the precautions for operating them. Thank you!
Hey, the moderator in charge up there – haven’t you searched on your forum? Using the search term “diaphragm metering pump” will yield a lot of information.
Principle: An electric motor drives the piston to move back and forth (note that the piston does not come into direct contact with the liquid), which in turn moves the diaphragm and sucks in the liquid, pressurizes it, and then pushes it out. Unlike ordinary centrifugal pumps, when starting, the inlet and outlet should be fully opened and the stroke adjusted to 0. Once operation is normal, the stroke is adjusted to the desired value. When shutting down, the stroke should first be set to 0 before turning off the motor; the inlet and outlet do not need to be closed.
Hehe, let me explain in detail: The electric motor drives the worm through a coupling (with bearings at both ends of the worm to hold it in place); the worm meshes with the worm gear, which is also held in place by bearings at its upper and lower ends. The worm gear causes the N-axis to rotate, and an eccentric block is mounted on this axis. An outer sleeve surrounding this eccentric block drives the larger end of the connecting rod to rotate, while the smaller end of the connecting rod is connected to the piston rod, thereby causing the piston (plunger) to move back and forth. The back-and-forth movement of the piston results in periodic changes in pressure within the oil guide chamber, which in turn causes the diaphragm to move back and forth, pushing the liquid from the inlet to the outlet.
Check the following posts: http://bbs.hcbbs.com/viewthread.php?tid=314503&highlight=%B8%F4%C4%A4 http://bbs.hcbbs.com/viewthread.php?tid=379810&highlight=%B8%F4%C4%A4
Principle: By utilizing the back-and-forth movement of the diaphragm, a change is created between the diaphragm and the pump head, which causes the ball valve to move up and down. This results in vacuum suction and pushing forces, thereby achieving the transfer of liquid. ①When the diaphragm is pulled backward, the outlet ball valve drops and seals tightly against the ball seat, while the inlet ball valve rises due to the vacuum created between it and the pump head as a result of the diaphragm being pulled backward, and the liquid is drawn upward along with it. ②When the diaphragm pushes forward, the inlet ball valve seals tightly with its seat, preventing liquid from passing through, while the outlet ball valve opens as a result of the diaphragm’s push, allowing the liquid to be discharged
When operating it, it is essential to keep in mind that the procedure is different from that of a centrifugal pump. When starting the pump, first open the inlet and outlet valves, then start the motor; when stopping the pump, first shut down the motor before closing the inlet and outlet valves