Measuring the head and flow of the pump is an important index to evaluate the performance of the pump. The following are the methods for measuring head and flow:
First, measure the lift of the pump
Head refers to the vertical height of the pump that can pump water from a low place to a high place, and can also be understood as the lifting capacity of the pump to water. There are several main methods for measuring head:
Pressure gauge method:
Install a pressure gauge at the inlet and outlet of the pump.
Read the values of both gauges and calculate the difference between them.
The head is calculated using formulas such as h=ΔP/ρg, where ΔP is the pressure difference, ρ is the density of water, and g is the acceleration of gravity.
Liquid level height measurement method:
Connect the outlet pipe of the pump to a vertical liquid level container.
Measure the height difference of the water surface in the liquid level container. This height difference is the head of the pump.
Pressure sensor measurement method:
Install a pressure sensor on the outlet pipe of the pump.
The head is calculated by measuring the outlet pressure and using the relevant formula or equipment. This method requires professional equipment, but the measurement results are accurate and reliable.
Mercury column measurement (not recommended) :
Connect the outlet pipe of the pump to a vertical mercury column.
The lift of the pump is determined by measuring the height difference of the mercury column. Due to the toxicity and environmental pollution of mercury, this method has been rarely used.
Second, measure the flow of the pump
Flow rate refers to the volume of water transported by the pump in a unit time. There are several main ways to measure flow:
Water collector method:
Place the water outlet of the pump into a water collector with a known flux.
Use a timer to measure the amount of water in the collector for a certain period of time.
The flow rate is calculated using a formula such as Q=V/t, where V is the amount of water and t is the time.
Float method:
Install a rectangular slot at the water outlet of the pump and place the lead with the float into the slot.
As the flow increases, the float rises.
The flow rate is calculated by measuring the height of the float on the wire and using the relevant formula or calibration curve.
Flowmeter method:
Use a flowmeter to directly measure the flow of the pump. The flow meter is installed on the inlet or outlet pipe of the pump, and the flow rate can be known according to the reading of the flow meter.
Calculated by specification parameters:
If there are flow parameters in the specification table or manual of the pump, you can directly consult and obtain. If there are no direct parameters, but the pump head, efficiency and other parameters are given, you can also use the relevant formula (such as Q=K×H×η, where K is the flow coefficient, H is the head, η is the efficiency) to estimate. However, this method requires knowing the exact flow coefficient and other parameter values.
Matters needing attention
Before measuring, ensure that the pump is in normal working condition and maintain stable operation for a period of time to obtain accurate measurement results.
During the measurement, attention should be paid to avoid the occurrence of pipeline blockage or leakage to ensure the accuracy and reliability of the measurement.
The measurement results may be affected by the wear and tear of the pump, load changes, and environmental factors, so the measurement should be performed periodically to evaluate the performance changes of the pump.
During the measurement process, the operation procedures should be strictly followed to ensure the safety of personnel and the normal operation of equipment.