What standard can i use to calculate the right place to put a control valve in a pipeline?

Field Instrumentation Valves
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what standard can i use to calculate the right place to put a control valve in a pipeline?

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use the Standard ISA RP4.2, below are some considerations;

In the design of an inlet and outlet valve, a recommended and widely used approach is to consider the control valve as a variable orifice area; thus the recommendations regarding the pipe, provided in an orifice plate system can be used in case of a control valve. Therefore, the following are basic recommendations:

  1. Leave the maximum stretch of straight pipe upstream of the valve. A good rule of thumb is to let 10 to 20 pipe diameters.

  2. Where possible, leaving a stretch 3-5 pipe diameters in the stretch downstream of the valve.

  3. The section upstream of the valve should allow the flow between the valve with a pressure stable, so we can have each new opening hole stable and repeatable flow.

  4. We install the pressure gauges upstream and downstream of the valve have to correctly reading only the static pressure and no static pressure reading plus or minus the dynamic pressure (speed) due to the flow of the stream format not uniform. The measurement of the pressure drop across the valve and the opening position of the valve indicates whether it is operating as designed with or is an internal problem.

  5. Whenever possible install shutoff valves upstream and downstream of the control valve aiming to make possible future expansion of the system and the maintenance of control with safety valve.

  6. The instrument air must be free of oil and moisture.

  7. Control valves should be protected by appropriate to eliminate internal damage caused by foreign objects inside the pipeline filters.

  8. Do not force the valve body to install it on the system, especially in split body valves.

  9. If the valve is operating on a dirty atmosphere, somehow protects the stem against abrasion.

  10. Make sure you follow all instructions in the manufacturer’s manuals on how to carry out correct installation of a valve as well as his early work.

  11. Make sure that the location where you install the control valve allows easy access for maintenance of the same or an emergency manual operation.

  12. Make sure that the free space left around the top and bottom of the control valve is sufficient to enable their maintenance remain the body on its own line.

  13. Take precautions to control valves operating with combustible fluids are sufficiently removed from equipment or hot lines.

  14. In case of corrosive fluids, protect the equipment or lines located near the control valve, due to the possibility of some kind of leak.

  15. Make sure the installation of drains upstream and downstream of the control valve to drain the trapped if need maintenance or removal of the valve fluid.

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