The electric control valve is an important execution unit instrument in the process of industrial automation process control. With the increasing degree of automation in the industrial sector, is being used more and more in a variety of industrial production areas. Germany Hank (HANK) electric control valve compared with the traditional pneumatic control valve has obvious advantages: energy (only when the work of electricity consumption), environmental protection (no carbon emissions), quick and easy installation (no need for complex pneumatic pipe And air pump workstations). The valve is divided into linearity, equal percentage characteristic and parabolic characteristic according to its function and characteristic according to the power used by its implementing agency.
1, electric control valve selection The main control parameters are: nominal diameter, design nominal pressure, medium allowable temperature range, flow coefficient and so on.
2, for the required flow and open height proportional relationship between the strict occasions, should use a special control valve. Ball valve and butterfly valve can be used when the general coarse adjustment.
3, the sealing performance of the valve is one of the key indicators of the quality of the valve.
Valve sealing performance mainly includes two aspects, namely, internal leakage and leakage. The internal leakage is the degree of sealing between the valve seat and the closing member to the medium. Exposure is the leakage of the valve stem, the leakage of the gasket in the mouth and the leakage of the valve body due to casting defects. Exposure is not allowed to happen.
4, the ideal flow characteristics of the control valve are open, parabolic, linear, and other percentage of four, according to the actual working flow characteristics with the appropriate choice of flow characteristics of the control valve.
5, the selection of the nominal diameter of the valve should be determined according to the required valve circulation capacity.
The nominal diameter of the regulating valve should not be too large or too small. Too large to increase the cost of the project, and the valve is in the low percentage range, the adjustment precision is reduced, the control performance is deteriorated. Too small, increase the system resistance, and even the valve will open 100%, the system still can not meet the set capacity requirements.
6, the adjustment valve regulator pressure and turn off the pressure difference
For the control valve, the allowable adjustment of differential pressure and shutdown pressure difference is an important indicator of its selection. The actual pressure difference is higher than the adjustment valve to adjust the pressure difference, the valve will not be able to accurately adjust the problem, serious damage to the valve actuator.
1, the control valve is a field instrument, requiring ambient temperature should be in the range of -25 ~ 60 ℃, relative humidity ≤ 95%. If it is installed in open air or high temperature occasions, should take waterproof, cooling measures. In a place where there is a source away from vibration sources or increase anti-vibration measures.
2, the control valve should be installed vertically, under special circumstances can be tilted, such as the tilt angle or the valve itself is too large when the weight of the valve should be increased support.
3, the installation of the valve control valve generally not from the ground or the floor is too high, the pipe height greater than 2m should try to set the platform to facilitate the operation of hand wheel and easy maintenance.
4, the control valve should be installed before the pipeline cleaning, remove dirt and welding slag. After installation, in order to ensure that no impurities remain in the valve body, the valve should also be cleaned again, that is, access to the media should make all the valve open, so as not to impurity stuck. After using the handwheel mechanism, it should be restored to the original neutral position.
5, in order to make the control valve in the event of failure or maintenance of the production process can continue, the control valve should be bypassed.
At the same time should also pay special attention to the installation of the valve position is consistent with the requirements of the process.
6, electric control valve electrical part of the installation should be based on the relevant electrical equipment construction requirements. In the use of maintenance, in the explosive place is strictly prohibited power cover maintenance and pry the surface of the explosion. At the same time in the disassembly do not knock or scratch the exposed surface, after repair to restore the original explosion-proof requirements of the state.
7, the implementing agencies of the reducer should be noted that after the repair lubrication lubrication, low-speed motor generally do not wash and refuel. After assembly should also check the valve position and valve opening indicator is consistent.