During the installation of the pump, depending on the piping condition, over feeding and shipon phenomenon can occur. Consequently, control of the flux can be unsuccessful, and the injected
flux can be much more than the amount set up. Also when injection point is connected to the discharge line of centrifugal pump, in which medicinal fluid is flowing, the medicinal fluid of the
medicine tank can be absorbed, even after the metering pump stops operation, due to the flow phenomenon of Venturi pipe. Back press valve can prevent above phenomena, and enable the exact amount
of discharge (as its set up amount)to be injected.
For the following cases, back pressure valve installation is needed.
When siphon phenomenon occurs, because the discharge board is lower than the water surface of the medicine feeding tank, on the inlet side.
When over feeding of medicine occurs, because the discharge line is thin and long, and causes inertia of the fluid.
When injection is needed into the vacuum tank or vacuum piping.