Hi Shiva,

Metering pumps develop flow against discharge pressure by means of a reciprocating piston that acts upon a diaphragm. This action produces a pulsating flow at the outlet of the pump. The piston action can be transferred to the diaphragm by means of a captive chamber of hydraulic oil, or by a mechanical connection. Flow is regulated through the pump by means of a set of check valves at the inlet and outlet connections.

The theoretical flow rate of a pump can be calculated by determining the volume displaced by the piston on each stroke, and multiplying that by the number of strokes per some time interval, for example one minute, or one hour.

For any given pump, the actual flow rate will never be exactly the same as the theoretical flow rate. This is due to various mechanical and hydraulic losses within the system, for example time losses in the check valves, or slip of hydraulic oil past the piston seals during normal operation.

The flow rate of a metering pump can generally be adjusted in one of two ways. The user can vary the distance that the piston travels, or the speed at which it reciprocates within the pump. For changes in the piston travel, or stroke length, a mechanical adjustment within the pump is used. In order to change stroke speed (frequency), some form of variable speed drive is used to change the rotation speed of the drive motor, for example a DC-SCR drive, or an AC VFD.

Hopes this information could help you.

Best regards,

Carlos E. Torres

Dear Shiva Gorjian 

It is very easy. You can find scheme in attached file. Using faucets 3 and 4 you can change flow rate, using faucet 6 you can change a pressure in divided cell.

If you send me some of your set-up I can try to explain what should you do.

My email: [email protected]

Best regards,

Yuriy Zmievskii