The main purpose of a valve is to control or regulate the flow of any pliable material within the equipment. There are various valve configurations and valve types that suit specific purposes. Different materials are also used for a large variety of conditions. Valves also prevent backflow and relieve pressure for gaseous applications.
There are several common types of valves. However, there are a lot more valve types used in particular applications. Those valve types are divided into subcategories depending on its operation principle. The seven common types of valves are Check, Ball, Gate, Globe, Plug, Diaphragm, and Butterfly.
The check valve is also called as a non-return valve. This type of valve constantly keeps the fluid moving in one direction which prevents backflow. Check valves automatically operate. It does not need human hands or external help to control its operation. There are several subcategories under the check valve. Disc or piston valves have sprung for faster operation.
It has three subcategories namely Swing Check, Ball Check and Piston Check valves. The Swing Check valve stops the reverse flow using a flap that sways to a seat. It is mostly used for vertical or horizontal forward flow.
The Ball Check valve remains true to its name with a ball sliding onto a hole which slows down the flow. The Ball Check is usually used for semi-solid materials like cement. The Piston Check valve has a spring-loaded plunger that stops the reverse flow of fluid.
Check valves have two openings. One of the holes is used for fluid entrance and the other is the exit point. Check valves are used with certain types of pumps. Mechanisms with pump-like functionality utilize this valve type. Injectors supplying water to steam boilers use this valve variant to avoid any reverse fluid movement.
Ball valves have great operating functionalities used in various applications. They are available in many sizes. Their advantages include functionalities like the low-pressure drop, operating torque and easy actuation. A ball valve uses a hollow, penetrated and pivoted ball that controls the flow.
This valve is open when the flow goes in line with the ball’s hole. Once it is pivoted at a 90-degrees angle by the handle, it closes. The handle aligns with the flow when opened but goes perpendicular when closed. The positions of the handle give visual confirmation which signifies the valve’s status.
Ball valves are known to be durable after many cycles. They are reliable and remain securely closed even if the equipment remained unused for long periods. This specific quality makes the ball valve great for complete shut-off operations due to its great throttling function.
The ball valve has five body styles specifically a single body, split body, three-piece body, welded and top entry. The difference of the body styles depends on how the ball valve is assembled like the casing carrying the ball.
Ball valves also have different types of ports that are distinguished by their function. Additionally, the “bore” of the ball mechanism has various styles. The style relies on the pressure as the ball valve is divided between low-pressure and high-pressure operations.
The gate valve’s other well-known term is the sluice valve. This valve type has a barrier which is referred to as the gate. It lifts the barrier, allowing the fluid to flow. Gate valves need a small space with the pipe axis. The barrier has a common wedge-shape gate to be able to put pressure on the surface.
Gate valves shut down the flow of liquid instead of regulating the flow. When the gate is opened, it does not obstruct the flow path. This results in lower flow resistance. This valve has a threaded stem connected to the actuator.
There is a rising or non-rising stem which depends on where the stem is connected. Rising stems are connected to the gate which rises and lowers together. Non-rising stem valves rotate with the actuator and threaded on the gate. Non-rising stems are utilized for limited vertical spaces.
The globe valve is an excellent choice for machines that needs a valve with throttling flow functionality. Globe valves have flow paths that change course. This increases the flow resistance with pressure drop.
This valve type is linear in motion. When opening or closing this valve, the disc shifts perpendicularly. Once the disk closes, the fluid’s kinetic energy helps to obstruct the opening. This quality is great for an operation that needs a quick-acting halt on the fluid.
When using a globe valve, avoid extreme close throttling when the pressure drop goes beyond 20%. Close throttling will lead to damage to the pipes and valves.
Plug valves have cylindrical plugs that can be rotated within the body which controls the flow. The plug valve has hollow passageways that go sideways, allowing the fluid to flow.
The design of this plug is tapered conically with the handle attached to the end. The stem of the plug valve comes in one piece. The other end is exposed to the outer valve, using a mechanism that keeps the plug to the body. The plug valve’s advantage is its simplicity and economical compared to other valves.
Diaphragm valves have a flexible disc that contacts the seat located at the top. The diaphragm valve has a responsive mechanism that gives force to open or close a valve.
The valve’s method of control is through the flexible disc attached to a compressor using a stud. The stud is molded to the valve. The manual diaphragm valve has good functionalities to control the pressure drop. The handwheel is turned to operate the compressor that either stops the flow or opens up for the fluid to flow.
The butterfly valve regulates or isolates the movement of a liquid. The valve’s closing mechanism uses a disk that rotates. The way it operates is similar to the ball valve for its fast shut-off quality.
The valve functions by rotating the disc to a quarter turn. The butterfly on its name is the metal disc placed on a rod. When the disc is turned, it completely blocks the fluid passageway. The valve opens when the disc rotates to a quarter turn. The opening unrestricted flow of liquid.
Butterfly valves are cost-effective, making it the most favored valve type in the industry. Despite lesser costs, the quality of the butterfly valve should not suffer. Multiple high-quality manufacturers produce affordable valves. An example is the Huamei butterfly valves which are built for high-performance operations.
Valves are small devices that are often overlooked. The only time they are noticed is when they are damaged in someway which hampers the flow of liquid or gas. Valves are intricate and have their own mechanisms. Every valve type serves an important purpose in every equipment operation. Choosing the right valve type would help the equipment function effectively and efficiently.