Detailed Information on Changeover Valves
by: Baz Herose
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Changeover valves have served reliably in many industries and several other applications; they are majorly used with dual relief valves. Generally, a valve is used in the regulation of fluid’s flow by opening, closing or incompletely blocking the various passageways. Valves may be automatically or manually operated. Manual operation of valves is done either by a lever, hand wheel or pedal while the automatically operated valves are driven by changes in temperature, pressure or flow.
Applications of Changeover Valves
Changeover valves are extensively used in Offshore, Plastic and Polymer, and also Oil and Gas (refining industries) to handle process media. These types of valves are switchover valves for switching from a pipeline to another; they are also called selector valves sometimes. They are ideal for applications where compulsory pressure relief piece of equipment are installed as double devices. These valve types are designed in a way that guarantees that one of the 2 pressure relief devices at least, is in service at all time and that complete relief flow is assured in the course of changeover.
Changeover valves are also used for other applications such as switching from a production line to another, choosing to and from multiple heat exchangers, choosing to and from double filtration systems, manifolding in situation where complete shutoff of media flow poses danger or becomes offensive or creates process stoppage. These valves are also used in applications for proportioning amid 2 sources of terminals, refluxing or even dumping.
Characteristics
• There’s possibility of shutting off the two valve outlets simultaneously
• Up to 7000C temperature ratings
• Ideal for pressure ratings of ASME 2500
• Actuation can be achieved by hand, electrical or pneumatic means
• Very low leakage to atmosphere
• Cleaning in service via flushing ports
• Combinable with multiple port valves
• Possibility of high level of customisation
• ... and so on
Now, depending on its application, the sizes for changeover valves can range from an inch to 24 inches standard; it can also be larger on request. Different materials are used in creating these valves; they include stainless steel, cast-steel, Titanium, nickel based alloys and Zirconium.
It is important to state that valves should be used according to the specification for which a particular type is made. For instance, globe valves are used for applications needing throttling and frequent operation; although they can serve in few other applications, but they do not function effectively in those applications. It is also very important to ascertain the reliability of the valve you are considering for purchase, in terms of industry standard certification and approval; this is the only way you will be assured of the quality of the valve you are considering for purchase.
Finally, it is ideal to purchase changeover valves and other valves from reliable suppliers. Search for renowned suppliers when you are considering the purchase of any type of valve for use in a particular application; it helps in ensuring that you are getting nothing but a reliable and high standard quality product.
About the Author
Herose Ltd is author of this article on industrial safety valves. Find more information about changeover valve here.
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