The regulating valve is a particularly important control equipment and are in common use in the industry, it is working properly or not directly related to the whole device production is normal or not. At present, with the development of control valve technology change rapidly, control valve manufacturer and the form of very many, also have different functions, the following introduces common problems that should be paid attention to in the installation and operation of various types of valves.

Valve pressure test valve pressure test, including the pressure test and leakage test valve spool valve is fully closed. Typically, when the design pressure exceeds 10MPa control valve, valve pressure test must be carried out to test the body itself and the pressure on the valve cover.

1, attention should be paid to the problem of test pressure regulating valve

1) valve body pressure test with manual pressure test pump pressure test, prohibited the use of electric test pump.

2) test medium for clean water.

3) the test pressure is 1.25 times the design pressure.

4) pressure test gauge should be used to verify eligibility, its accuracy should not be less than 1.5, the scale should be the upper limit for the test pressure of 1.5 ~ 2 times.

5) opening gas valve during the valve opening pressure test valve to open at least 20% of the time, it must be borne in mind, in order to prevent the high pressure spool unilateral damage. Typically the spool valve is to allow a certain amount of leakage, according to the level of difference between control valve leakage, generally only require a high differential pressure control valve (V, VI level leakage) for leak testing.

Should pay attention to 2 problems, the leak test

1) valve body pressure test with manual pressure test pump pressure test, prohibited the use of electric test pump (VI grade pneumatic valve leak test)

2) test medium for clean water (VI grade of valve leakage using clean air).

3) the maximum differential pressure design test pressure for the valve leakage level at work (see the design parameters).

4) pressure test gauge should be used to verify eligibility, its accuracy should not be less than 1.5, the scale maximum test pressure is 1.5 ~ 2 times.

3, valve single adjustment newly installed pneumatic control valve should be installed before the single adjustment. Performance tuning should achieve: basic error: ± 1.5% return error: 1.5% dead zone: 0.6% now, regulating valve and electric valve positioner manufacturers is very much, have different functions, electric valve positioner tend to intelligent, specific adjustment method is different, it is no exaggeration.

4, control valve control valve installation is installed should focus attention, the installation quality directly related to the operation and performance of control valve. We should pay attention to the following problems during installation:

1) regulating valve before installation, the valve must be carefully cleaning the dust accumulated during storage, should be kept clean during installation. Because the dust and impurities within the seat will be damaged. In order to protect clean, usually cover installed in the day of the opening is not welded flange end.

2) regulating valve installed, the arrow on the valve body should be consistent with the medium flow.

3) regulating valve is a precision component, if they are pipe deformation stress, will undermine the normal work. Therefore, the flange and pipe installation should be vertical and accurate location to avoid deformation of the pipe. Well, the pipeline should be appropriate support, to prevent its occurrence under the weight of the valve deformation.

4) regulating valve in the pipe welding and must be especially careful. If the control valve and pipe welding inadequate attention, not to eliminate stress, will be deformation. Welding, welding slag must be strictly avoided splashing into the valve, the presence of welding slag undermine the performance of the valve, if the splash splashing directly on the spool, ranging from direct impact on the valve action, heavy damage to the spool and the valve seat.

5) pipeline pressure test and purge, the valve should be removed, with the corresponding straight Duan Xianglian to prevent the welding slag, iron cutting and other debris stuck in between the spool and the valve seat. Remove the control valve open flange end use of plastic sheeting wrapped firmly.

5, the linkage test valve linkage test installed in the drive after the device must be. Linkage test should focus on the following points:

1) before the control valve linkage test must undergo a rigorous process pipeline purging and qualified, not qualified purge valve piping installation is prohibited, because the pipeline of residues such as welding slag, dust and other debris can damage the valve hard with the valve seat sealing surface.

2) check valve butterfly valve ends not with a pressure test or plugging blind before the linkage.

3) with hand wheel control valve, hand wheel should be in "release" position. Check whether the supply pressure valve can meet the requirements of the control valve of the gas supply.

6, in the industrial automation instrumentation installation, valve installation and commissioning the most complex, the most difficult and the most problematic. Throughout the process, instrumentation and piping professional expertise should coordinate and support each other, cooperate closely, timely solve problems promptly reflected, in strict accordance with the requirements, according to operating procedures, the only way to ensure smooth valve installation and commissioning quality quality to ensure the smooth progress of the installation project and the plant went into operation.