Pressure sensor measures water pump head
Thread Content
Gentlemen, I have a question. We have a project on site, where a pressure gauge and a pressure sensor have been installed almost 50 cm apart on the pipeline. The gauge reading is 12 meters, while the pressure sensor reading is 19 meters. Dear experts, please help identify the possible reasons why the pressure readings from the two pressure devices can differ so much. Another thing is to measure the head of the water pump using a pressure sensor; the reading from the pressure sensor should equal the difference between the position where the pressure sensor is installed and the water level, plus the frictional and local losses along the path from the water pump to the pressure sensor. Is the pressure value measured by the pressure sensor the same as the pressure required in the pipeline behind the sensor?
Are they all connected in front of the pump outlet valve?
In engineering, the pressure difference ΔP between the inlet and outlet of a pump is generally considered to be the pump’s head. P1/ρɡ+z1+V1²/2g+He=P2/ρɡ+z2+V2²/2g+Hf ； When the diameters of the pump’s suction and discharge pipes are not very different, the velocity head can be ignored, as well as the friction losses and the height difference at which the pump is installed (i.e., the difference between Z1 and Z2). Generally, the pressure difference ΔP between the pump’s inlet and outlet is considered to be an approximation of the pump’s head. To measure the pump’s head more accurately, it is necessary to determine the flow rate, the diameters of the inlet and outlet pipes, as well as the height difference. Additionally, pressure gauges and vacuum gauges should be installed at the pump’s inlet and outlet. I wonder if the original poster understands.
Pay attention to the installation location; if it is in the same place. A pressure gauge is generally a primary instrument, while the sensor, which may provide a digital display, is a secondary instrument. The calculation for the water purification head has been provided above; one just needs to determine which value corresponds to the parameters in the formula.