Dosing pump installation and pipe laying Precautions: to prevent pipe vibration discharge fluid due to inertial resistance, at the beginning of the pump operation, the pipeline will have pulsating impact force. This is a peculiar phenomenon of reciprocating pumps, caused by the sudden acceleration of the liquid in the pipe. In order to prevent this phenomenon from occurring, we request that the discharge end has an inertial resistance (Pid) <1.0kgf / cm2. When the Pid reaches 1.0kgf / cm2, the piping will vibrate, adversely affecting the pump and its peripherals. The solution: 1. Install pulsation damper; 2. Increase the diameter of the outlet pipe and shorten the length of the outlet pipe. To prevent excessive supply of excess supply is due to the flow of liquid inertia in the pipeline, affecting the normal operation of the check valve, the check valve failure, resulting in the pump flow is too large, unstable. This phenomenon may occur whenever there is insufficient negative pressure at the suction end or the piping is too long. Therefore, we require: Pump differential pressure> Inertial resistance Pi (greater of inlet or outlet). The solution: 1. Install the pulsation damper; 2. Install the back pressure valve; 3. Try to shorten the length of the import and export pipelines; prevent cavitation occurs If the device cavitation margin (NPSHa) is insufficient, the pump may be due to flow or gas Erosion is damaged. Therefore, we require installation cavitation allowance, NPSHa> NPSHr, and NPSHa = Pa-Pv ± Phs-Pis * (* or the larger of Pfs). Pa: Absolute pressure of liquid surface kg / cm2Pv: Vapor pressure of liquid surface kg / cm2Phs: Relative pressure (kg / cm2, height of liquid inlet) Take "-" Pis: water inlet inertia resistance kg / cm2Pfs: water inlet pipe resistance kg / cm2.
