Hydraulic balancing problems
Introduction
A control valve or regulating valve is a valve used to control the flow of a fluid, behaving as an orifice of continuously variable area, which modifies the pressure drop, as directed by the signal from a controller.[1] This allows control of the flow rate and the consequent control of process variables such as; pressure, temperature and level.
In the terminology of the Regulation and control technique, the valve is the control organ or final control element..
Structure of a valve
They basically consist of a body that houses the plug and the seats inside and externally they are provided with flanges or threads for coupling to the pipe. They must resist the temperature and pressure of the fluid without losses, they must have an adequate size for the flow to be controlled and they must resist erosion or corrosion produced by the fluid. They are usually made of iron, steel or stainless steel and lately they are beginning to be made with thermoplastic materials.
The plug can have linear or rotary displacement and performs the function of controlling the passage of the fluid. Both it and the seats are usually made of stainless steel. Ceramic plugs and seats are used in some valves.
When the valve is activated by the actuator, a change in the fluid flow rate occurs, thus achieving regulation of the process variable.
Types of valves according to their use
Contenido
La variedad de válvulas en cuanto al diseño del cuerpo y al movimiento del obturador es enorme. Aquí se limitan a los tipos genéricos usados más normalmente. En principio se distingue entre válvulas de dos, tres y cuatro vías.
Las válvulas de dos vías se utilizan principalmente en instalaciones de caudal variable y las de tres vías en instalaciones de caudal constante y temperatura variable. En realidad esta es una definición demasiado simplista, pero puede servir como punto de partida.