The control valve is a control component in the fluid conveying system, which has the functions of diversion, interception, regulation, throttling, prevention of backflow, diversion or overflow pressure relief, etc. It is used to control air, water, steam, various corrosive chemical media, Movement of various types of fluids such as mud, liquid metal and radioactive material.

Many end users request a review of their technical specifications to identify areas that add unnecessary cost and lead time to their valve, actuator, positioner and related accessory purchases.

In many cases, these errors increase cost and lead time, as users specify control valves in applications where less expensive options also work. Not only are these oversized valves more expensive up front, they are also more difficult to maintain and require more spare parts.

The biggest challenge for most capital construction projects for control valves is cost justification. Often, valve upgrades or new valve projects are based on what has been done traditionally. Unfortunately, this often includes the use of outdated technologies, unnecessary choices, and overly strict specifications and standards that add avoidable costs.

Process engineers are increasingly recognizing the need to integrate designs without these layers. Instead, they want to use industry standards and generic designs rather than custom fit-for-purpose approaches, which increase cost and development time.

Starting from scratch, using only the items necessary for safety, legality and reliability, valve suppliers can help evaluate applications and make value-driven choices.

There are many types of control valves

The requirement that a rotary valve must have a splined shaft to limit idling does not include oversized rotary valves and fork-type pneumatic actuators, which often hurt project cost and lead time.

The exclusion of threaded seat rings and bonnetless bolting specifications take users to more expensive valves by eliminating cost-saving alternatives. It is incorrect to state that reactive spring diaphragm actuators with seals or glands should be avoided. If the valve must fail to open, a reverse acting actuator is required.

All options are available as a valve manufacturer, and it's hard to know if something in the spec will eliminate options that might reduce the overall project cost. Control valves are widely used in the chemical industry and are a common adjustment device used to control fluid flow, pressure and liquid level in the production process. In the application of control valve, calculation and selection are the prerequisites, installation and debugging are the key, and use and maintenance are the purpose. If the control valve is improperly selected, improperly installed or poorly debugged, it will not be able to adjust. Therefore, the installation of this control valve is relatively simple, and there is no complicated installation process. The pneumatic control valve uses compressed air as the power source, uses the cylinder and the membrane as the actuator, and uses the electrical valve accessories to realize on-off or continuous adjustment, and receives control signals to adjust the flow, pressure, temperature and other process parameters of the medium. Pneumatic valves are mainly divided into two types: air-open type and air-close type, which are characterized by simple control, fast response, intrinsic safety, and no need for explosion-proof measures.

The main failure modes of pneumatic control valve are: the internal leakage valve does not act, the opening degree fluctuates greatly, the jamming phenomenon occurs, the action is normal but the flow rate does not change. The main reasons are: valve body failure, cylinder failure, positioner failure, control cable failure, inadequate maintenance, valve quality problems, selection or design reasons, and pneumatic component failures.

The sealing performance of the piston sealing ring is not enough, the temperature of the sealing ring is too high, and the sealing part is damaged for too long. Troubleshooting method: Grind the cylinder and re-adjust the cylinder limit bolts, re-select the sealing ring according to the operating temperature, and install it correctly when replacing.

Valve positioners are divided into pneumatic valve positioners, electrical valve positioners and intelligent valve positioners according to the input signal.

If you want to know more about the product, you can contact us by phone: +86-510-87883666

Or send an email to: Jshanlishi04@jshanlishi.com