Operation requirements for pneumatic control valves

In order to ensure the working performance and reliability of pneumatic actuator valve, we must follow the operation requirements. Here are the requirements.

 

Firstly, we should ensure the quality of pneumatic actuator valve. For its selection we have to go through strict calculation, such as pneumatic valve actuator types, caliber, each performance must meet the requirements, materials for various parts of control valve must be strictly selected, which should have sufficient strength and stiffness,  also should pass electric strength test, air tightness and other tests in accordance with the national standards. The manufacturer's techniques and testing methods must conform to the standards.

 

Secondly, to ensure reliable operation. Pneumatic actuator valve itself manufacturing quality, and including the improvement of operator training and quality. In order to prevent misoperation, the technician should pay attention to the notes on the nameplate. According to China's new pneumatic control valve standard (GB/T4213-92), the nameplate of the pneumatic actuator shall at least indicate the manufacturer's name, product model, rated flow coefficient, design number, product number and manufacturing date and other matters. The arrow and DN value representing the direction of medium flow and the words and values of PN shall be cast or rushed out on the valve body. Important valve actuator accessories should be adequate, such as valve positioner and actuator, limit switches, etc. There should be enough space for installation and operation, enough lighting and strict operation  rules.

 

Thirdly, it must have emergency device. In case of malfunction of high-pressure gas equipment, in order to prevent it from directly damaging other equipment, a cut-off equipment must be installed on the pipeline which connects the device, and a quick cut-off valve should be installed if necessary. There should be strict rules for leakage of quick shut-off valve. In a fire—prone situation, it should be considered the fire resistance of the control valve from the structure, or using fire coating method. Emergency devices, includes fireproof bag, which can be put within minutes and are made of materials containing layers of ceramic or glass fibers, we can also use the method of connecting rod protection, such as fusible connected rod actuator, heating connected electric rod actuator, these connecting rods start when they are heated and disconnect with no need, but it can make the valve move to a safe position.

 

Fourthly, it should be environment-protecting, the importance and necessity of protecting the natural and living environment is well known. The pollution of pneumatic control valve to the environment is mainly air pollution and noise. In order to prevent air pollution, the sealing part of the valve should not leak. We should pay attention to the sealing method and the selection of sealing materials. When the fluid is toxic, such as CO medium, we should consider using bellows seal or more reliable sealing method. In order to prevent the leakage of more fearful radioactive fluid, it is necessary to comply with the requirements and rules for the use of nuclear power station. Noise prevention is very important, which is very prominent in the environmental protection of control valves. Now, there are mainly mechanical noise, liquid dynamic noise and aerodynamic noise. Let's take measures to prevent it. Apart from it, energy saving should be considered, during the use of the regulation, we should connect energy saving with control valve structure, use, installation and maintenance.

 

Fifthly, we should use low impedance valves. The resistance of fluid flow valve is so small that reduces energy consumption. When using pneumatic actuated ball valve, ball core hole and the diameter of the pipe if they are at the same, it can save the power consumption of air compressor  actuator, pump equipment. Compared to some traditional valves, these valves have larger capacity, which can have the same flow adjustment under smaller pressure difference. The purpose of energy saving aldo can be achieved by utilizing some of the structural changes in the valve internals, such as using a low S value control valve.

 

Sixth, we should improve the sealing performance of valve core and angle seat valves, because poor sealing prevents valve from closing completely and the pressure drop caused by leakage causes power loss. In order to improve the sealing performance, it is possible to replace the pure tetrafluoroethylene manufacturing seat with materials such as glass fiber teflon or graphite, sealing gaskets with high hardness, mazy sealing surface and other methods can be used, but it can't damage the sealing surface.

 

Lastly, we use electric valve actuator as much as possible. Because the use of  air pneumatic actuator can only operate with air pressure, consuming a lot of energy in a year, but use electric actuator. When we change the opening level, once the valve reach the required opening it will stop the power supply.   

 

In addition to the above, pneumatic control valves should be suitable for new energy sources. For a long time, oil is a major energy, but in recent years, many new energy, the pneumatic control valve needs more special requirements from processing to production to transportation, storage.