What is a Check Valve?
A check valve is a valve that is used to prevent backflow in a pipe system. A non-return valve, or NRV, is another name for it. The pressure of the fluid moving via a pipeline opens the valve, whereas any flow reversal closes it.
It is referred to as a two-port valve because it has two ports on its body, one for accepting fluid and the other for discharging it. Check valves come in a variety of shapes and sizes and are utilised in a variety of applications around the world. Check valves are common in ordinary home products. Check valves are available in a variety of sizes and costs, although they are typically relatively simple, affordable, and compact.
Types of check valve
- Based on Swing Type.
Top Hinged
Tilting disk
- Based on the Lift Type
Piston Type
Ball type
- Dual Plate Type
- Stop Check Valve
Parts of the Check Valve
- Body
- Body Seats
- Gasket
- Cover Plate
- Hinge
- Nuts
- Washer
Body
The valve body, which also houses the disc and stem, is the principal pressure-retaining component. This also permits flow from the valve; its end connection is pipe; depending on the size and pressure of the piping system, this end can be welding type, threaded, or a variety of others.
The valve body can be cast or forged in a range of materials, including cast steel, stainless steel, and alloy steel, depending on the application.
Body Seats
The valve seat is a surface inside a valve’s body that makes contact with the disc, which is a moving component that restricts and enables flow through the valve. It serves various critical functions, including the following: Keeping compressed or combustion gases out of the manifold.
Gasket
A gasket is an important part of the flanged connectors of a plant’s piping system. A gasket is a sealing substance or a mixture of materials that is clamped between two independent mechanical elements of a mechanical joint (flanged joint) and serves as the weakest link in the connection.
Hinge Pin
A double offset pivot (hinge pin) design is used in a high-performance tiling disc check valve. The pivot offsets are created when the valve is built with hinge pins that are placed below the midline of the sealing surface and slightly to one side of the pipe centreline.
Nuts
A nut is a fastener that has a threaded hole. To secure numerous parts together, nuts are nearly typically used in conjunction with a mating bolt.
Washer
During installation, washers protect the surface from damage. They evenly distribute pressure and keep the fastener from shifting or corroding. Skipping washers can drastically affect the lifespan of your product’s construction.
Advantages and Disadvantages of check valve
Advantages of check valve
- Very quick reaction
- Can withstand both low- and high-pressure issues
- Backflow should be reduced
- Minimize downtime and less production loss
- Less maintenance cost
- Carbon footprint is very less
- Power source is not required
Disadvantages of check valve
- Reverse flow is costly and can cause a pump to spin backwards, resulting in damage.
- Jabbering happens as a result of frequent valve opening and closing in some check valve systems.
- High noise issues
Applications of Check valves
- Keep drinking water safe from contamination caused by backflow caused by gravity, back siphonage, or backpressure (ex: Hose connected kitchen spray or shower hand spray).
- Protect sensitive equipment against potential damage or contamination caused by a change in flow direction (ex: water meter, pump or filter).
- To prevent drainage or to ease restart, keep water in a system or pipe after the flow has been shut off (ex: pumping systems).
- In systems with differential line pressures, prevent crossover flow (ex: Cold and hot water inlets in thermostatic mixers).
- Reduce the possibility of backflow or leakage in the event of a valve failure (e.g. solenoid valve at the inlet of an appliance).
- Allow for the proper operation of complicated systems by assuring unidirectional flow (e.g. multi-zone heating system or booster pumps).