（Relevant requirements and methods for pressure test of imported valves）
（Industrial valves are not subject to strength test in use, but after repair, the valve body and bonnet or the valve body and bonnet damaged by corrosion shall be subject to strength test. For safety valve, its set pressure, reseating pressure and other tests shall conform to the specifications and relevant regulations. The valve shall be tested for strength and tightness during installation. Spot check 20% of low-pressure valves, 100% of unqualified ones; 100% of medium and high-pressure valves. The commonly used media for valve pressure test are water, oil, air, steam, nitrogen, etc.）
（In this paper, the famous imported valve brand German Rockwell valve pressure test standard requirements and procedures to analyze the pressure test related issues.）
1、 Pressure test method for inlet valves
（1）. The upper sealing test and shell test shall be carried out first, and then the sealing test shall be carried out
Upper seal test
Close the inlet and outlet of the valve, loosen the packing gland (if the valve is equipped with an upper sealing inspection device, and the upper sealing performance can be reliably checked without loosening the packing gland, it is not necessary to loosen the packing gland). The valve is in a fully open state, so that the upper sealing is closed, the body cavity is filled with test medium, and gradually pressurized to the test pressure, and then check the upper sealing performance
（2）. Shell test
Close the inlet and outlet of the valve, press the packing gland to maintain the test pressure, and the opening and closing parts are partially open. Fill the chamber with test medium and gradually pressurize it to the test pressure (the check valve shall be pressurized from the inlet end), and then check the shell (including the stuffing box and the connection between the valve body and the valve cover).
2、 Requirements for pressure test of inlet valve:
（1）. Pressure test shall be conducted for each valve before delivery. The famous brand of imported valves, Germany lock, strictly implements this standard.
（2）. Before the completion of shell test, it is not allowed to paint the valve or use other anti leakage coating, but it is allowed to carry out chemical anti rust treatment without sealing effect and lining the lined valve. For painted stock valves, if the user's representative requires to redo the pressure test, the coating does not need to be removed.
（3）. Before the sealing test, remove the oil stains on the sealing surface, but it is allowed to apply a thin layer of protective agent whose viscosity is not greater than kerosene. For the valve sealed by oil, it is allowed to apply the oil selected according to the design regulations.
（4）. During the test, the valve shall not be subject to external forces that may affect the test results.
（5）. Unless otherwise specified, the temperature of the test medium shall be between 5-40 ℃. However, in some valves which need to meet the working condition of high temperature medium, the medium can also be used for test sealing.
（6）. The following test media shall be selected by the manufacturer, but shall meet the requirements of Table 1 and table 2; a liquid: water (antirust agent can be added), kerosene or other suitable liquid with viscosity no more than; B gas: air or other suitable gas.
（7）. When testing with liquid, the gas in the valve chamber shall be removed. When gas is used for test, safety protection measures shall be taken.
（8）. During the sealing and upper sealing test, it shall be closed in the way given in the design.
（9）. The test pressure shall meet the requirements