What Precautions Should Be Taken In Water Meter Calibration

What precautions should be taken in water meter calibration

Shengda suggests paying attention to the installation direction of the water meter when calibrating it, and placing it horizontally on the clamping device. During the calibration process, the valve should be started quickly to reduce errors.

Under working pressure, the distance between the water surface and the outlet pipe in the stabilizing tank should be greater than 10 times the diameter of the outlet pipe. The inlet and outlet pipes of the stabilizing tank should be set at sufficient distance to prevent the kinetic energy of the incoming water from interfering with the stability of the outlet pressure as much as possible. When releasing pressure and removing air, it is necessary to release pressure in sequence and move slowly to avoid excessive impact, which may cause the piston to break the measuring instrument.

Strictly follow the calibration operating procedures, and when reading values, the scale corresponding to the maximum rotor area should be read. The accuracy of a rotary flowmeter is determined by factors such as the accuracy of the calibration device, reading resolution, and the condition of the conical tube taper medium.

In addition to the error of the calibration device itself, the calibration device should be placed in a place with good lighting and ventilation, and should be kept as far away from vibration sources as possible to avoid external interference. In addition, the instantaneous flow indicator needle adopts a glass rotor flowmeter. The glass rotor flowmeter needs to be installed vertically without tilting, and the flow direction of the medium should move from bottom to top. In addition to measurement errors caused by friction and contamination during use, the presence of bubbles on the rotor and the verticality of the installation of the rotor cone tube can also cause additional measurement errors. It is necessary to pay attention and avoid them as much as possible during use. Therefore, it is important to pay attention to the correction of the displayed values during use.

Factors affecting the calibration results of water meters:

In the volume calibration of water meters, the flow range can be controlled by a glass rotor flowmeter. Before calibration, the gas is discharged. However, during use, fluctuations in water pressure caused by turbulence, vortices, and detachment in the pipeline, as well as the presence of bubbles in the water, can cause deviations in the calibration results of the water meter.

The water temperature can work normally when the calibration water temperature is between (0.1-30) ℃ or 50 ℃, meeting the measurement performance requirements. However, too low water temperature can affect the measurement performance of the water meter, which is characterized by a slow display of the minimum flow rate.

During the process of placing the tested meter on the calibration table, opening the clamp to clamp the water meter in the front and back straight pipe sections, closing the flow control valve, and opening the inlet valve, the air inside the pipeline and water meter was not completely discharged while the water meter and pipeline were subjected to water pressure.

During the calibration process, when the water level of the working gauge reaches the predetermined value, close the flow control valve. When the water level of the working gauge is still, there is a slight difference between the concave surface of the water level and the predetermined value on the working gauge. At this time, a reading can be taken and calculated. Sometimes, due to carelessness, incorrect readings may be read.

The sealing components of the two position four-way valve, clamp, and drain bottom valve of the calibration device are all O-ring oil resistant rubber rings. After prolonged use, water leakage may occur due to friction. In this case, it should be replaced in a timely manner. If the O-ring oil resistant rubber ring is not replaced, it will cause errors in the water meter due to water leakage.

The scale, scale line, and glass tube of the calibration device for water meters should be kept clear, otherwise it will affect the reading. The reading error of the water meter scale can affect the accuracy of water meter calibration. When reading with the water meter scale, the line of sight must be parallel to the concave part of the liquid level. Both high and low readings can affect the measurement results.