Check valves are small, convenient valves that are used in a fluid or gas control application to prevent fluids from flowing in the reverse direction, which prevents damage and ensures efficient operations. Check valves are used as one-way or non-return valves in practically every industry. Check valves are a useful addition to a wide range of fluid and process control applications due to their size and adaptability. So, if you’ve ever wondered what a check valve is or how it works, have a look at our helpful explanation below, which explains all you need to know. Learn more from check valve manufacturers, about the purposes of check valves, the many types of check valves, and some of the high-quality check valves available at Fluid Controls.
High Pressure Check Valve
Forged Check Valve
Tilt Disc Check Valve
Brass Check Valve
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What is a Check Valve?
A check valve permits fluids to pass only in one direction. They feature two ports, which implies there are two openings in one body, one for fluid entry and one for fluid release. They’re known as ‘one-way valves’ or ‘non-return valves’ because they only allow fluids to flow in one direction. A check valve’s primary function is to prevent backflow in the pipeline.
A pressure differential is required for a check valve to function. To open the valve, they need more pressure on the inlet side than that on the output side. The valve will shut if the pressure on the output side is too high or the pressure on the input side is too low to overcome the opening force. The closure mechanism varies based on the valve type. They do not require a handle, lever, actuator, or person to function properly, unlike other valves.
Check valves are normally tiny, basic, and affordable, despite the fact that they come in a broad variety of sizes and prices. Most check valve bodies (outer casings) are constructed of plastic or metal.
Working: Check Valve
The check valve’s operation is primarily determined by the pressure differential between the outlet and intake ports. When the pressure on the intake side of the valve exceeds the opening force, the valve opens the path for fluid to flow. As the flow reverses, the pressure at the outlet port rises above the pressure at the intake port, causing the valve to close its passageway and stop the flow.
There are three main terms related to working of a check valve:
- Cracking Pressure: A minimum upstream pressure is required to open a check valve and allow flow through it. The ‘cracking pressure’ of a check valve refers to the minimum upstream pressure at which the valve opens. The particular cracking pressure varies depending on the valve type and size, so make sure your system can produce it and is appropriate for the application.
- Closing: The valve will get close if the upstream pressure drops below the cracking pressure or if there is a reverse flow. The closing mechanism of a check valve might vary depending on its design. Backpressure closes an opening by pushing a gate, ball, diaphragm, or disc against it. The closing action might be supported by a spring or gravity, which depends on the type.
Installation of the valve: Because a one-way valve only functions in one direction, knowing the proper installation orientation is critical. The flow direction is usually indicated by an arrow on the valve casing. Otherwise, you’ll have to inspect the valve to make sure it’s fitted in the right direction. If it’s reversed, flow won’t be able to go through the system, and pressure will build up, eventually causing harm.
Types & their construction: Check Valve
It’s crucial to understand the many types of check valves accessible while learning more about what a check valve is. Continue reading to learn more about the check valve manufacturers and types of valves provided by them.
- A Swing Check Valve is a basic mechanism that allows a liquid or gas to flow in just one direction. It has a hinged disc that opens to enable fluid to flow in and then closes to prevent backflow. Swing check valves are available in a range of sizes and characteristics to suit a number of applications. There are a few minor changes to the swing design that are better suited to specific scenarios.
- The flow for Lift Check Valves comes in through the valve’s seat. The disc or ball is lifted off the seat by the flow’s pressure. Gravity drives the disc or ball down into the seat as the flow reduces, pauses, reverses, or stops. The design resembles that of a standard Globe valve. They are generally used in high flow and velocity conditions.
- The pivot point of a Tilting Disc Check Valve is in the middle of the disc, allowing fluid to flow over the top and bottom of the disc. They’re commonly employed in situations where there’s a lot of flow reversal. When the disc is open, the flow maintains it open, unlike a swing check valve, which is kept open by the velocity of the flow. The disc is tiny and lightweight, and its centre of gravity is at the pivot point. With low flow rates, it has a low-pressure drop, while with high flow rates, it has a larger pressure drop.
- Ball Check Valves are spring-loaded and employ a ball to prevent fluid passage. The ball is moved backwards in reverse flow to stop the flow. The ball gets pulled away from the flow when there is enough pressure in the flow. It drops down to close the pathway when the pressure reduces.
- A dual, folding disc, double disc, or splits check valve is another name for a Butterfly Check Valve. During forward fluid flow, the halves of the disc expand toward the centreline, as shown in the diagram. The halves open and close the pipe in reverse flow. The smashing impact on the discs is reduced by the small distance the halves must travel. Butterfly check valves are perfect for heating, ventilation, and air conditioning systems because they function quietly.
- Any type of check valve can be used as a Stop Check Valve. A mechanism such as a lever, handwheel, stem, or other devices that may firmly close the valve to cease liquid flow distinguishes it from a standard check valve. The disc is stopped from sliding off the seat when the lift check valve and globe valve are closed.
- A Foot Valve is just a check valve with an intake strainer that is fitted at the end of a piece of piping/hosing since their input does not have a connecting point. In-line spring supported or in-line ball check valves are common check valve types used in foot valves. They only enable flow in one direction and are supported in closing by a spring. On the inlet side, a strainer prevents debris from entering the check valve and clogging or damaging equipment downstream. They’re usually found at the end of a pump’s suction line in a water reservoir, a fuel tank, or any other purpose where the suction line is below the pump. As a result, they may be utilised to keep pumps primed, prevent liquid from syphoning back into the line, and keep debris out.
- Duckbill Check Valves are designed like a duck’s beak that is manufactured from rubber or synthetic elastomer. The inlet opening end of the valve is stretched across the supply line’s outlet. The opposite end, on the other hand, preserves its original form. Upstream pressure opens the duckbill lips, enabling the flow to pass through. The lips spread wider as the pressure increases. As the pressure decreases, the lips flatten and shut again.
3. Composition Disc: To provide better sealing, a firm and non-metallic filler ring is inserted on the disc of a composition disc design. Composition discs are utilized for high temperature and pressure applications because of their strong durability and excellent corrosion resistance. The composition disc globe valve is an effective & better version of the standard disc globe valve. Replacement or repair of composition discs can be done easily.
Application: Check Valve
Since its creation at the turn of the twentieth century, self-sealing valves have been the go-to solution for backflow problems in various sectors. A check valve nowadays is present in the system of every industry that transfers products through pipelines.
Check valves are cost-effective waste-prevention and equipment-protection mechanisms. Fluids travelling via a pipe network must be protected from loss due to improper handling. When pressure or flow falls, check valves immediately stop the liquid flow by stopping backflow and retaining the fluid.
Check valves are found in many industries which are attached to different equipment’s of the piping system, some of those uses are:
- Pump: Check valves are employed with several types of pumps. Inlet and exit ball check valves are extensively used in piston-driven and diaphragm pumps, like metering pumps and chromatographic pumps. These valves are frequently shaped like little cylinders connected to the pump head on the intake and exit lines. Check valves, such as ball check valves, are used in many other pump-like systems for transferring different fluids.
- Gases: When several gases are combined into a single gas stream, check valves are frequently utilised. Each of the distinct gas streams has a check valve placed to prevent the gases from combining in the original source. If fuel and an oxidiser need to be combined, check valves on both the fuel and oxidiser sources are often employed to guarantee that the original gas cylinders stay pure and hence non-flammable.
- Pharmaceuticals: Fluid flow in the pharma industry necessitates the use of check valves to improve or quality of product, efficiency, and productivity. Check valves also maintain the pressure in the fluid flow.
- Irrigation System: Check valves are placed near the irrigation system’s source to stop flow reversal, or siphonage, of irrigation water back to its source.
- Fuel Injection System: Check valves can be found in automobiles built before the electronic injection system was invented. A check valve is situated at the inlet and one is located at the outlet of old automotive fuel pumps. They are meant to cause the gasoline to flow in the proper direction. The fuel pressure drops when the check valve fails.
- Water: Check valves are used in many water applications like potable water and wastewater systems. For potable water system check valves ensure that no foreign media enters the system and contaminate it. Also in the wastewater system, check valves to make sure that wastewater cannot re-enter the system and cause overflow and contamination.
- Compressed Air System: Check valves allow the compressor to hold some sections pressurised while keeping other sections depressurised. They may be found on the intake and exit of a piston compressor, as well as the air receiver and discharge pipe.
Valve Selection: Check Valve
Many considerations must be addressed while selecting a check valve for your application to guarantee the best performance. Check out some of the criteria for check valve selection here:
- Make sure that any check valve you employ is made of materials that are compatible with the liquid or gas you’ll be using.
- An in-depth study should include valve rating, line size, type of installation (horizontal or vertical), measurements and connection type, maximum leakage rate, pressure drop, and any other specific requirements. It’s also crucial to make sure you’re using the right kind of valve for the job.
- The proper size of a check valve is an important aspect that is frequently overlooked. To avoid flutter, a lower Flow coefficient (Cv) value valve is necessary for applications where there is an insufficient flow to maintain the valve against its stop. To guarantee that the valve is fully open or closed under normal operating conditions, check valves should be sized based on the individual application instead of the line size. This feature of check valves is frequently neglected, and it is often realized that such issues are caused by poorly selected check valves rather than the valves themselves.
Advantages: Check Valve
Check valves are compact, basic, and affordable, and come in a variety of sizes and costs. They also prevent backflow and reverse flow from causing damage to pumps and compressors. They cut down on downtime and production losses caused by inappropriate valve failure. Because of the minimal pressure drop, they save energy and are extremely useful at preventing water hammers.
Top 5 Check Valve Manufacturers in the World
Company Name: Emerson
Type of Business: Check Valve Manufacturer
Company’s Address: 8000 West Florissant Avenue, St. Louis, MO 63136, United States
Contact Information: +1 314 553 2000
Other Products: Control, Isolation, Solenoid, Relief Valves, etc.
Applications: Nuclear Plants, Subsea, Petroleum Industry, etc.
Company Name: Powell Valves
Type of Business: Manufacturer
Company’s Address: 2503 Spring Grove Ave, Cincinnati, OH 45214, USA
Contact Information: 5138522000
Other Products: Gate, Globe, Butterfly, Bellow sealed Valves, etc.
Applications: Petrochemical, Industrial Gas, Pulp & Paper, Mech Construction, Power, etc.
Company Name: BEL Valves
Type of Business: Check Valve Manufacturer
Company’s Address: 11 Glasshouse Street, St Peters, Newcastle upon Tyne, NE6 1BS.
Contact Information: +44 (0) 191 265 9091
Other Products: Gate, Globe, Ball, Rotary Disc, Needle, Block and Bleed Valve, etc.
Applications: Surface, Onshore, Subsea, etc.
Company Name: AVK International
Type of Business: Manufacturer
Company’s Address: Bizonvej 1, 8464 Galten, Denmark.
Contact Information: +45 87 54 21 00
Other Products: Ball, Butterfly, Control, Sluice Valves, etc.
Applications: Fire Protection, Water, Gas, Irrigation, etc.
Company Name: Flowserve
Type of Business: Check Valve Manufacturer
Company’s Address: Flowserve World Headquarters, 5215 N. O’Connor Blvd., Ste 700 Irving, TX 75039 USA
Contact Information: 972-443-6500
Other Products: Ball, Butterfly, Rotary & Linear Control, Gate, Globe, Plug Valve, etc.
Applications: Oil & Gas, Chemical, Power, Water, General Industries.
We are a check valve manufacturer and here in this article, we have provided brief information about a check valve. If you want more information about the valve and how to select a valve, our experts will guide you based on your requirements. Thanks for reading this article, you can also comment or leave your feedback here in the comment box.