Soft seal gate valve is a valve often used for pipeline water. Since the water in the valve will flow through the pipeline of the product valve, the different material of the valve will also affect the quality of internal water. What is the specific impact?
The pipes of the existing soft seal gate valve water supply network in China are generally steel pipes and cast iron pipes. When the factory water is corrosive or the service life of the pipeline is too long, the inner wall of the pipeline will corrode and scale, and the reproduction of microorganisms will also lead to the scaling of the inner wall of the pipeline. The rust contains a large amount of iron, lead, zinc and various algae. When the water flow velocity, direction or water pressure in the pipeline changes suddenly, it will cause the deterioration of water quality in a short time and the sharp rise of iron, manganese, chromaticity, turbidity and index value. Studies have shown that for metal pipelines without anti-corrosion treatment, when the service life exceeds 5 ~ 10 years, the dirt has reached the degree of deterioration of water quality. For metal pipelines with poor anti-corrosion treatment, corrosion begins to appear in 3 ~ 5 years. The longer the service life of the pipeline, the more serious the corrosion is, and the worse the water quality is.
Using metal as water supply pipe material will cause secondary pollution to water quality. Generally speaking, the water quality can meet the standard before entering the urban pipe network. However, because it is not pure water, it generally contains some metal elements, compounds and microorganisms. When water flows in the pipeline, due to the separation of chemicals, the falling off of the coating material of the soft seal gate valve pipeline, the attenuation of residual chlorine and other reasons, the water and the material of the inner wall of the pipe have a chemical effect.
For the air leakage mode of soft seal gate valve, the following are common:
1. The air leakage of the solenoid valve on the cylinder may be due to the high air pressure in the pressure reducing valve.
2. The exhaust hole of the cylinder leaks because the two moving parts inside the cylinder and the sealing ring at the sealing part of the cylinder block are aging.
3. The upper and lower parts of the cylinder leak, which is because the sealing ring at the seal between the actuator and the cylinder does not achieve the sealing effect due to the frequent activities of the actuator.
4. In addition to the above three cases, there is another case that may also cause air leakage of the cylinder, that is, the spring in the cylinder is damaged, which is caused by the force not in place, which may also cause the closing not in place.
When solving the problem of cylinder air leakage, it should be considered according to the actual situation. For example, whether the soft seal gate valve is gas open or gas closed. For the air open valve, we can first close the hand valves at both ends, and then let the central control open the valve. First disassemble the connecting piece at the connection, and then cut off the air source. At this time, release the gas at the pressure reducing valve. Note that the actuator will rotate 90 ℃, and then change it. After that, pay attention to moving the actuator back to the original position.
When the soft seal gate valve is less than or equal to DN500, the number of opening and closing cycles shall not be less than 500, and that of electric valve shall not be less than 2500. When it is greater than DN500, the number of opening and closing cycles shall be reduced. The operating performance and sealing test of soft seal gate valve shall be carried out under the specified operating torque or force. In addition to the conventional test items such as strength, sealing, operation function, size, material and low pressure test, the protective epoxy coating must also be tested. When the soft seal gate valve is used for drinking water, it must also be subject to sanitary evaluation or third-party certification.