A control valve is a piece of equipment that must be mechanically and chemically resistant enough to withstand pressures, temperature, fluids in its working conditions; the valve acts responding to a signal from the process controller, the signal is sent to the positioner that opens or closes the valve, thus leaving the process variable at the desired value.
The Control Valve is one of the essential elements in the process. The Control Valve comes when the process needs to be highly efficient, where the fluid needs to be meticulously controlled.
Types Of Control Valves
There are valves with linear and rotary displacement principles. Examples of valves with linear displacement are straight or angular body globe valves. Control valve sliding disc type, which are valves with extremely polished discs that have passages, one of the disc is fixed to the valve and the other slides over it, modulating the passage of the fluid, in this case, the pressure that the fluid exerts on the obturator is perpendicular causing the valve actuator does not exert as much force to modulate, this valve can act very quickly compared to other types, this perpendicular force can help to reduce the valve size consequently helping to reduce the weight of the valve.
As an example of valves with rotary displacement times, sectored ball valves, and high-performance butterfly valves, these can also control the variable at the desired point. Still, they are not much used compared to linear displacement valves.
There are still other essential characteristics of these valves that make it necessary to select, for example, the number of ways. It can be a valve in two or three ways, for fluids with low and high temperatures—a control valve for sanitary processes.
Information Required For Sizing And Acquisition
To acquire a Control Valve from blackhawksupply.com, it is necessary to inform some data of how the valve will be installed. Upstream and downstream pressure is significant to define the valve size together with the process flow.
Minimum and maximum process temperatures must also be informed. The fluid may vary its characteristics according to temperature changes such as specific mass and kinematic viscosity, thus changing the Reynolds number. The flow rate and diameter must also be entered and are related to the fluid velocity in the system and directly related to the Reynolds number.
Every control valve is sized by software from large manufacturers. The sizing is highly accurate, as a valve poorly sized by larger sizes can cause inaccurate controls, and excessive valve wear or by smaller sizes can restrict the process flow.