A check valve is frequently used in systems that allow fluid media to flow only in one direction. Sewer lines, for instance, where waste should only flow in one direction, are examples of such systems. Where backflow could harm equipment, check valves are also used.

Let’s first examine the operation of a check valve before reviewing the various check valve types, applications, and selection criteria.

Check Valve and its functionality:

A check valve, also known as a non-return valve, limits fluid flow to just one direction. In order to stop fluid backflow in various industrial systems, check valves have two ports: an inlet port and an outlet port.

There are various types of check valves, and each one differs from the others in terms of how they open and close. To allow or impede fluid flow, they all, however, rely on a pressure differential. Check valves operate correctly without the use of a lever, handle, actuator, or a person, in contrast to other valves on the market. They are affordable, efficient, and simple to use.

Nevertheless, a pressure difference between the inlet and outlet ports is required for the check valve to function. The “cracking pressure” is the minimum pressure differential that the system must exceed in order for the valve to open. Depending on the size and design, this cracking pressure varies from one checking valve to the next.

The valve will close if there is back pressure or if the cracking pressure is greater than the inlet pressure. The closing mechanism of a check valve varies depending on its design; for example, a ball check valve closes by pushing a ball against the orifice. Gravity or spring can also help with this closing action.

Check Valves Types:

Check valves come in a variety of varieties, each created for a particular application. But one kind—the spring-loaded in-line check valve—is employed in various industrial settings.

A spring, a valve body, a disc, and a guide are all components of the spring-loaded in-line check valve. The disc is pushed, the orifice is opened, and fluid can flow through the valve when the inlet pressure is high enough to overcome the cracking pressure and spring force.

Backpressure seals the valve by pressing the spring and disc against the hole or orifice. A quick response time during closing is made possible by the short travel distance and the quick-acting spring. 

This type of valve must be completely removed for inspection or servicing because it can be installed either horizontally or vertically, according to the system.

The other types of check valves are as follows:

• Spring-loaded Y check valve
• Ball check valve
• Diaphragm check valve
• Lift check-valve
• Swing check valve

Applications for check valves:

Nearly all industries where fluids must flow in a single direction use check valves. Additionally, these valves are utilized in home appliances like dishwashers and washing machines.

Check valves can be utilized for any of the following use cases depending on their design and mode of operation:

• Avoid fluid backflow damaging equipment.
• Stop siphoning.
• Halt contamination brought on by backflow.
• To maintain a vacuum seal.

Selection criteria for check valves:

When selecting a check valve, you should take into account several things, such as:

• The check valve’s material’s suitability for the fluid medium.
• The system line’s size for a precise connection.
• The size of the envelope.
• The minimum and required cracking pressure.
• Accessibility is required for maintenance and repairs.
• Installation orientation.
• The valve’s temperature requirements concerning the fluid media.

DAWSONS-TECH Check valves are standard industrial equipment that is affordable, dependable, and reasonably simple to operate. Make sure you comprehend your requirements and the check valve selection criteria before making a check valve purchase.