GB/T 13929-2024Water ring vacuum pumps and compressors - Testing method (English PDF)

4.2 Test medium and working fluid

4.2.1 The test medium is ambient air, with a temperature range preferably from 0 °C ~ 35 °C.

4.2.2 During testing, the pump inlet water temperature shall not exceed 35 °C, which is preferably 15 °C. The water shall be clean; the water supply volume and pressure shall comply with the relevant technical documents.

4.3 Uncertainty of test instruments All instruments shall have verification certificates or reports and shall be verified or calibrated according to the specified cycle. The measurement uncertainty of all types of instruments shall meet the requirements of Table 1 for the uncertainty of each measurement parameter. - For single-stage water ring vacuum pumps, the suction pressure point is 400 hPa; - For two-stage water ring vacuum pumps, the suction pressure point is 80 hPa; - For water ring compressors, the maximum permissible operating pressure point.

4.7 Performance test

4.7.1 The performance test of the water ring vacuum pump shall measure the gas volume, shaft power, efficiency, ultimate pressure at different suction pressures under the test speed. The performance test of a water ring compressor shall measure the gas volume, shaft power, efficiency at different discharge pressures (including the maximum permissible operating pressure) at the test speed. During the pump performance test, the bearing temperature, ambient air temperature, ambient air relative humidity, atmospheric pressure, discharge temperature, temperature, pressure, flow rate of the supplied water shall be measured simultaneously (see Figure 1).

4.7.2 When performing performance tests on a single-stage water ring vacuum pump, the number of measurement points shall not be less than 12 (including the measurement points specified in 4.8.2). Additional measurement points shall be added in areas where the gas volume curve changes significantly; the number of additional measurement points shall reflect the changes in the gas volume curve. When performing performance tests on a two-stage water ring vacuum pump, the measurement points shall start from the suction pressure of 200 hPa to the ultimate vacuum; the number of measurement points shall meet the buyer's requirements. When the buyer has no requirements, the number of measurement points may be appropriately selected, but shall at least include the measurement points specified in 4.8.2. When conducting performance tests on a water ring compressor, the number of test points may be appropriately selected according to the buyer's requirements, but shall include the test points specified in 4.8.2.

4.7.3 When conducting performance tests on a water ring vacuum pump equipped with an atmospheric ejector, the number of test points may be appropriately increased. In addition to measuring the performance of the water ring vacuum pump when operating alone, the gas volume, shaft power, ultimate vacuum when equipped with an atmospheric ejector shall also be measured.

4.8 Exit-factory tests

4.8.1 The performance test points for exit-factory tests shall conform to the buyer's specifications. If the buyer has not specified, the performance test points shall be conducted according to the following provisions. - Single-stage water ring vacuum pump. Ambient air pressure (or close to ambient air pressure), suction pressure of 400 hPa, ultimate vacuum; - Two-stage water ring vacuum pump. Suction pressure of 200 hPa, 80 hPa, ultimate vacuum; - Water ring compressor. Ambient air pressure (or close to ambient air pressure), the midpoint between ambient air pressure and the maximum permissible operating pressure, and the maximum permissible operating pressure.

4.8.2 The vibration and noise operating points for exit-factory testing shall be as specified by the buyer. If not specified by the buyer, the following shall apply. - For single-stage water ring vacuum pumps, the point of suction pressure 400 hPa; - For two-stage water ring vacuum pumps, the point of suction pressure 80 hPa; - For water ring compressors, the point of maximum permissible operating pressure.

5.2 Measurement of suction pressure (vacuum)

5.2.1 The suction pressure shall be measured at the pump inlet, using a liquid column manometer (U-tube manometer or single-tube vacuum gauge) or a spring vacuum gauge. The inner diameter of the connecting pipeline for the measuring instrument shall not be less than 6 mm. The pipeline shall not be bent; the sealing of the connecting pipe shall be ensured to prevent blockage due to condensation.