Need To Know About Pressure Relief Butterfly Valve Castings

Pressure relief butterfly valves are flow controlling devices which isolate or regulate the flow of any fluid. Its closing mechanism is a rotating disk, unlike the ball valve. With its expanding usage throughout different industries, butterfly valve castings are very high in demand, globally. So, let’s take a quick look at the basics of these valves to understand their relevance.

How does it operate?

The basic principle of operation is identical to that of a ball valve, which allows for a quick shut off of flow. But usually people are more biased towards the former because of their comparatively lower cost than the latter. In addition, butterfly valves are lighter in weight, hence requiring much less support. A butterfly valve’s basic functioning design is:

• A disc is placed at the centre of a pipe.

• A rod passes through that disc to an actuator placed outside of the valve.

• By rotating the actuator, the disc can be turned parallel or perpendicular to the flow.

• Unlike the ball valve, due to the constant presence of the disc within the flow, there is a pressure drop induced even when open.

The butterfly valve belongs to the group of quarter-turn valves. While operating, the valve completely opens or closes with the rotation of a quarter turn of the disc. The “butterfly” comprises nothing but a disc made of metal, which is placed on a rod. The disc is twisted at the time the when the valve remains closed and this ends up blocking out the passageway, whereas, when completely open, the disc on the valve gets a quarter turn rotation, to allow the fluid flow in an unhindered manner. The valve can be opened in a gradual increasing method, to enable throttle of the flow.

Different Kinds of Butterfly Valves

There are different kinds of butterfly valves available to suit different pressures and usages. The most common kinds are-

• Wafer-style butterfly valve: This type of butterfly valve has a designed to keep up a blockage against pressure gap that is bi-directional, to stop it from flowing back in systems that are meant to have unidirectional flow.

• Lug-style butterfly valve: In these types of valves, both ends of the body have threaded inclusions which enable installation of the valves into a system that has just two bolt sets, without any nuts. This setup allows either sides of the piping arrangement to be disconnected without affecting the other side.

• Rotary Valve: These kinds of valves comprise a variation of the basic butterfly valve where pockets are included in the butterfly as an alternative to being flat.

Usage of Butterfly Valves in Industries

• Butterfly valves are frequently used in the chemical, pharmaceutical as well as the food industry.

• These valves are also used by firefighters on their hoses to limit their pressure.

• These are also abundantly used on front and rear suction ports, tanks and water pumps.

• In case of specific valves, it is possible that the valve may perform additional functions; e.g.-cast iron butterfly valves not only act as a regulatory device but can actually stop and start the flow as desired.

Due to its low cost, high functioning and simplicity of installation, butterfly valves have been replacing ball valves in their several usages (like the petroleum industry). But it is important to make sure that the valves used in these industries are manufactured according to the CGMP (Current Good Manufacturing Practice) guidelines. In different industries, butterfly valve castings are preferred and appreciated alike, by virtue of their efficiency and simplistic design.

A Comparison Between Butterfly Valve and Ball Valve Castings

The butterfly valve and the ball valve are the two most commonly used valves in the industrial sector. The two have many similarities and dissimilarities. While they look very different from each other, both of them tend to perform very similar functions. This article about ball valve castings and more will bring to you a comparative study of the ball valves and butterfly valves.

The similarities:

·         Both of them are essentially made by combining a variety of different metals like stainless steel, brass and cast iron.

·         Both of them are very commonly used because of their high durability and shelf life.

·         Both of them are also economical, which makes them always be high on demand.

·         Both of them can be used at different temperatures for the regulation of flow of a variety of gases and liquids.

The differences:

·         The construction and look of the two valves are vastly different. The ball valve castings have balls with holes through them. The butterfly valves on the other hand have disks mounted on rotating shafts.

·         The working procedures of the two are also different. The ball valve opens, blocks or partially opens a hole in the ball to control and regulate the flow. The disk is what the butterfly valves use. The handle is used in the latter case to turn the disk by ninety degrees to either let the flow completely through or to completely block it.

·         The pressure drops involved with the two valves are different in nature. In the ball valves, there is hardly any difference in pressure and that is a huge advantage. The ball valve will turn no matter how much pressure is being exerted from the end of the supply unit. However, the same is not true for butterfly valves. In this case, with the interfering nature of the disk, there is always a drop in the pressure. This can go on to have serious problems later on.

·         In the sector of uses, both have their own advantages and disadvantages. Ball valves are better overall but more expensive. They are most commonly used for the flow of gas. This is because they have a better sealing mechanism with very low chances of leakage.

On the other hand, butterfly valves are economical and boast of low maintenance. They are used for public services like municipal water projects and sewage control. Even projects that involve redirecting or controlling the flow of streams or rivers, butterfly valves are the chosen options.

A careful inspection of both must be done before you choose to use one for your necessity. Understanding the structure and function of both is necessary to pick the perfect valve for the function you need it to perform. Ball valve castings as well as butterfly valves are available widely and easy to procure. You should feel free to contact a trusted manufacturer who can explain and choose the best suited valve for you. Do your research well before investing as it always better to be safe than sorry.