A closure member which is rotated into or away from a seat to modulate flow. A constant (Cv) related to the geometry of a valve , for a given valve travel, that can be used to predict flow rate. A valve which controls the flow rate or flow direction in a fluid system.
This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. In automatic control terminology ,. Chapter explains desuperheaters, steam conditioning valves , and turbine bypass systems.
Chapter details typical control valve installation and maintenance procedures. Valve Types and Features. The three basic functions of valves are: 1. To select the correct valve to fulfill these functions properly, an outline of the different types of valves and their features is given below. The principle is simply a knife or gate which is dropped in front of the flow. Knifegate valves should never be used in a restrictive role (ie half open) as the base of the knifegate will wear rapidly and not seal properly when closed.
High rangeability allows a valve to control flow from large to small flows Rangeability is affected by three factors: 1. They are designed such that if the air supply fails, the control valve will be either fully open, or fully close depending upon the safety requirement of the process. The control valve commonly named the final control element of control contains a pneumatic device that convert the control signal from the controller in action regulating the process fluid flow.
A control valve that regulates the flow of fluid falls in the regulation category. Most commonly used are plate valves, ring type valves and poppet valves. Depending on the application different types could be used for a recip compressor.
Chapter covers desuperheaters, steam conditioning valves, and turbine bypass systems. Chapter covers the selection and use of special control valves. The most common types are ball valves, butterfly valves, globe valves, and gate valves. When fully open, a ball valve creates little turbulence or resistance to flow.
The valve stem rotates a ball which contains an opening. Chapter Flow control valves - Used to regulate flow in a hydraulic circuit 9. Needle - Can throttle flow Globe - Note suitable for throttling Gate - Used as on-off valves Figure 9. MODULE OBJECTIVES: Atthe end ofthis module, you will be able to: 1. There are many valve designs and types that satisfy one or more of the functions identified above. A multitude of valve types and designs safely accommodate a wide variety of industrial applications.
Regardless of type, all valves have the following basic parts: the body, bonnet, trim (internal elements), actuator, and packing. Class 1gate valves consist of a square joint in 2” and an oval one for all other sizes. Class 3and 6valves consist of a circular spiral wound gasket. Class 9and above gate valves consist of a ring type joint.
Linear motion valves having globe , diaphragm or pinch type closures.
Ideal for quick shut-off, since a 90° turn completely shuts-off, compared to multiple 360° turns for other manual valves.
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