Great functionality of pneumatic diaphragm control valve is a key to general plant performance and to optimum process control. pneumatic diaphragm control valves do have difficulties which are traced to inadequacy of their design itself, or due to their misapplication. Those difficulties can be generally broken up into two categories, i.e. design-selection and procedures-maintenance.
Valve replacement has been the conventional way of addressing valve issues in the first category. This typically results in the original valve being inadequate in most instances, for the particular service because of misapplication. Valve replacement’s process is well understood and the option is effective so long as the root cause of problems is addressed. This makes the total price of solving the original valve problem much greater than the cost of the hardware.
Retrofit is an excellent choice for solving pneumatic diaphragm control valve difficulties. The retrofit alternative can be engineered specifically to address the root cause of difficulties. It is a low-risk and an economic option when accurately used, where large sizes of valves are involved and notably in acute service applications. Retrofit of these valves eliminated the first difficulty of under capacity completely and the standard elevation on these valves is now 50%, providing sufficient ability to respond to transients.
Their use in many safety-related applications in nuclear power plants has proven the reliability of retrofit solutions. Retrofitting is an option that has to be considered when solving design-selection valve problems that are related. They may be engineering-intensive and need expertise. When correctly applied, they could eliminate root cause of problems.
It’s no doubt a properly applied retrofit option can attain many benefits. There will be prices that are lower. Most of the parts in the setup price, including engineering, cutting conduits, welding, and pressure testing are dramatically reduced if not removed. Because of this, the total cost is not significantly more than that for a valve that is new. Besides, the danger is also lower. The threat to the end-user is also lower, since the internal measurements of the body are not changed. Additionally, there will be lower downtime.
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