Ever wondered how much important valves are in our daily life? Why does every industry depend on this tiny device?
Valves are flow control devices that have applications from taps in our house to the aerospace industry. You will find a number of different valves in the market; each one of them will have different models, features and designs. Every valve is designed to perform a particular operation. This article is all about valves and their types. Read the complete article to get familiar with 19 important types of valves:
1. Ball valve
The ball valve is a device that regulates the flow of fluid using a hollow and perforated ball. The valve is open when the hole in the ball aligns with the fluid inlet and close when the valve’s lever is rotated 90 degrees. Speaking of handling, the ball valve provides an easy shut on and off feature. The ball valve is highly reliable, that’s why it has a long working life. The components of the ball valve include seat, stem, body, ball and lever. When it comes to high pressures and temperatures, this valve performs equally well as in normal conditions. Due to its versatility, ease of operation and durability, the ball valve is preferred over gate and globe valves. Its drawback is the entrapment of water in the central cavity while in the closed position when the ball valve is used to regulate water flow. So, when the temperature drops below freezing point, the formation of ice can cracks the side of valves.
2. Globe valve
Globe valve regulates the flow of fluid using a movable disc or plug. The disc or plug seats over the valve seat and move towards or away from the seat to start and stop the flow. In a manual globe valve, a lever controls the shut on and off function. The valve is named as globe valve due to its spherical body. The components of the globe valve include body, seat, cage, bonnet, stem and disc. Looking inside, the body of the globe valve consists of two halves and an internal baffle to separate them. About its construction, the body is usually made of stainless steel, brass and other rustproof alloys. Globe valves are available in multiple sizes ranging from 12 mm to 300 mm. Like ball valves, globe valves can work in high pressure and temperatures. One disadvantage of the globe valve is the high pressure drop in fluid flow.
3. Gate valve
The gate valve is a flow control device that blocks the fluid flow instead of regulating it using a single or double barrier (gate). It is also known as a sluice valve. This valve is generally used in large diameter pipes because it is pretty easy to construct in large sizes compared to other valves. At high pressure, friction may be an issue making it hard to operate the valve. Talking of benefits, the gate valve is lightweight, economical and offer low pressure drop. Moreover, it is operational up to a pressure of 280 psi and temperature of 675°C. However, the opening and closing of a gate valve are time-consuming.
4. Check valve
Check valve, also known as a one-way valve or non-return valve, permits the fluid to flow through in one direction only. It is small and inexpensive, that’s why it is common in various household items. The body of the check valve has two openings, one for the entry of fluid and the second for the exit of fluid. Mostly, they are automatic and do not require a handle or lever to operate. Plastic and metal are frequently used for the external structure of the check valve. Moreover, these valves are suited to work over a wide range of pressure. Check valves are available in different sizes, types, and costs for different applications. A lift-type check valve uses a ball or piston, which is supported by a spring that opens at high pressure and closes as pressure decreases. Swing check valves use spring-actuated hinged gates or wafers to control the flow.
5. Butterfly valve
Butterfly valve manages the flow of fluid using a disc called flapper, vane or blade. The disc rotates vertically or horizontally and allows the content to flow. A rod passes through the disc and is connected to a handle on the outside of the valve. The butterfly valve is good for throttling operation. Like ball valve, the butterfly valve is a quarter-turn valve, but it is preferred more due to its low cost, easy installation, and less support. A pressure drop can be observed because the disc is always present within the flow. About its usefulness, the butterfly valve is extensively used in food, chemical, and pharmaceutical industries. One drawback of the butterfly valve is that it is more leak-prone than ball valve.
6. Diaphragm valve
The diaphragm valve closes the flow of fluid using flexible membranes. In addition to membranes, the diaphragm valve consists of a seat on which the diaphragm sits, a body with two or more ports. The membrane can be either rubber-lined type or fluorine plastic-type. Depending upon the applications, the body is formed of plastic, wood or metal. The diaphragm valve is controlled by manual, pneumatic, hydraulic and electric actuators. Diaphragm valve can be classified as weir type and straight through type. Weir type diaphragm valve is more common and require low thrust and shut off stroke. On the other hand, straight through types suitably handle viscous fluids and slurries.
7. Plug valve
A plug valve controls the flow of fluid with the help of a cylindrical or conical plug inside the valve body. The plug contains one or more hollow passages through which fluid flows when the valve is open. Furthermore, the plug valve is affordable and simple. The plug valve can be opened or closed by giving a quarter turn, similar to the ball valve. Bringing up its pros, the plug valve is easy to operate, require less space for installation, has quick action, high capacity and low weight. Plug valves can be either lubricated or non-lubricated. The lubricated valve serves in the oil industry, which means it can handle harsh conditions. On the other hand, non-lubricated plug valves are used in the food and pharmaceutical industry where contamination is to be avoided.
8. Piston valve
The piston valve controls the fluid flow through a pipe using a cylindrical plug. Piston valves serve for isolation service in steam, condensate, and other liquid systems. Key specifications of piston valve include its size and materials of the valve body, seat, and stem.
9. Needle valve
A needle valve precisely regulates the fluid flow by inserting and withdrawing a tapered stem into or out of an orifice. It has applications in vacuum systems and metering systems where accurate flow regulation is mandatory. Since numerous turns of the stem are required to start and stop the flow completely, the needle valve is not appropriate for a simple shut off function. Unlike a ball valve, it is hard to tell just from observing the handle position whether the valve is open or close.
10. Float valve
The float valve maintains the fluid in the tank at a specific level. It is a mechanical device that employs hollow spheres mounted on the lever, which open and close fluid inlets. The float valve is used in toilets to fill up the water level after a flush.
11. Pinch valve
A pinch valve is a flow control device that blocks the fluid flow by pinching effect. It can be employed for on, off and throttling operations. Pinch valve construction includes a replaceable sleeve made of rubber, plastic or polymer depending upon the operating temperature and valve body. The flow of slurries, dry products, gravel etc., is efficiently managed by a pinch valve. Pinch valve has a low initial cost, low maintenance cost and low pressure drop. In addition to this, it is workable at a temperature up to 250°C and pressure up to 20 kg/cm2. But it is not appropriate for vacuum operation.
12. Blind valve
The blind valve, also known as 8 blind or blind flanges, completely obstructs the pipe flow and allows safe construction, maintenance, and such other activities. It uses a solid plate to isolate the fluid, and hence there is zero leakage of fluid. This valve also provides a visual indication; the worker can easily observe the position of the valve. Furthermore, the blind valve is easy to operate and install but is not useful for high flow volume applications. The design is simple but can get complex when size is increased, and safety features are added. The blind valve has a locking mechanism for tightening and loosening of the blind.
13. Control valve
The control valve is a power-operated device that manages or manipulate the flow of gas, steam, water, oil and other fluids. Pneumatic, hydraulic and electric actuators achieve the opening and closing of the control valve. However, a pneumatic actuator is most reliable and common. The action is initiated upon receipt of the signal from a controller such as PLC. The control valve is manufactured in different designs according to the operating conditions, required applications and pipeline layout. The main components are valve body and actuator, while the most common construction materials are cast iron, nickel alloy, Hastelloy and even plastic. It has a size ranging from 3mm to 500mm.
14. Cock valve
Cock valves or stop cock are quarter-turn valves that allow the user to control the flow from an external point. It is actuated manually. Cock valves can be used for isolation and regulation purposes. Applications of cock valves include petroleum pipelines, low-pressure steam applications, gas and fuel applications, plumbing and wastewater system, power plant applications and much more.
15. Slide valve
The slide valve contains a sliding mechanism to control the flow of fluid passing through the valve. The valve slides move in the rectilinear path to block and unblock the inlet and outlet ports. The slides act as a barrier, and between the slides, there are two parallel seats. The slide valve is suitable for low pressure flow of gases, liquids, suspensions etc. The features of the slide valve include low pressure drop, extensive size range (50mm to 1500mm), workable at up to 650°C temperature and 25 kg/cm2 pressure. Such valves are usually used in car engines to allow the fuel to enter the cylinder and exhaust gases to escape.
16. Angle valve
Angle valve, also called stop valve, has inlet and outlet ports at 90° angle with respect to each other. It comes in multiple designs and sizes. The high-quality angle valve is used in heavy operations. The ideal material for angle valves is copper because it provides longer service life as compared to plastic and zinc alloys. The angle valve is frequently used in industries and residential plumbing. The valves used in industries need to be dependable and reliable to ensure the safety and efficacy of operations.
17. Cartridge valve
Cartridge valves, also known as 2/2-way valves, internally manipulate hydraulic systems’ direction, pressure, and flow. It is a type of inline valve, which means it acts parallel to the fluid flow. Cartridge valve is perfect for operation where high flow rates and leak-free control is necessary. It consists of the sleeve, valve poppet and closing spring. The cartridge assembly is designed to fit in the cavity and kept in place by a cover. Some of the benefits of cartridge valves are reduced energy consumption, low pressure drop, greater stability, and cost-effective control.
18. Balancing valve
The balancing valve regulates the fluid flow by equally dividing the flow into multiple flow branches. Primarily, it is used in HVAC and fluid power systems such as heating/cooling systems, refrigerators and power generation. It also provides counterbalancing force for double-acting cylinders. Some prominent types of balancing valves are static balancing valves, dynamic balancing valves, and fixed orifice balancing valves.
19. Solenoid valve
A solenoid valve is an electromechanical gadget that starts or stop the flow of air and oil remotely. The two-port design is adopted to regulate flow, while the three-port design switches the flow between ports. The tasks of the solenoid valve include shutting off, distributing, dosing, release and mixing fluids. Solenoid valve has applications in so many fields, but it is frequently used in fluidics. The usefulness of this valve is due to its compact design, high reliability, quick and secure switching, low control power and long work life. Generally, the valve is made up of brass, aluminum, stainless steel, and plastic. The valve body should be compatible with the fluid. However, the solenoid valve is sensitive to voltage, and the flow can affect valve fluid.