Metering pump installation and pipeline laying should pay attention to matters needing attention

Dosing pump installation and piping laying precautions To prevent the pipeline vibration discharge fluid due to inertial resistance, at the beginning of the pump operation, will have a pulsating impact on the pipeline. 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 require that the discharge end has an inertial resistance (Pid) of <1.0 kgf / cm2. When Pid reaches 1.0 kgf / cm2, the piping will vibrate, adversely affecting the pump and its peripherals.
The solution: 1 installation of pulsation damper;
2. Increase the outlet pipe diameter and shorten the length of the outlet pipe.
â—† To prevent excessive supply of excess supply is due to the flow of liquid in the pipeline inertia, affecting the normal operation of the check valve, the check valve failure, resulting in excessive pump flow, instability. 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 installation of pulsation damper;
2. Install back pressure valve;
3. try to shorten the length of the import and export pipeline;
◆ prevent cavitation occurs If the device cavitation margin (NPSHa) is insufficient, the pump may be damaged due to flow or cavitation. Therefore, we require installation cavitation allowance, NPSHa> NPSHr, and NPSHa = Pa-Pv ± Phs-Pis * (* or the larger of Pfs).
Pa: absolute pressure of the liquid surface kg / cm2Pv: vapor pressure of the liquid surface kg / cm2Phs: relative pressure (kg / cm2, height of the liquid inlet) Pis: inlet resistance inertia kg / cm2Pfs: inlet pipe resistance kg / cm2

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