What is a check valve?
Strataflo check valves are anything but ordinary, but it’s important to know the basics of exactly what these devices are and their function. A check valve is a mechanism with two ports, an inlet where fluid or gas enters and an outlet where it exits. This design ensures flow moves in only one direction.Check valves operate on the concept of cracking pressure. This is the minimum pressure differential required to open the inlet end of the valve and allow the flow of fluids or gases to the outlet end. It can also be referred to as opening pressure. The amount of required cracking pressure, which is measured in psi, determines the size and type of valve needed for a particular application. Back pressure is when the pressure at the outlet end of the valve is greater than the inlet end. The amount of back pressure required to close the valve and prevent flow is referred to as reseal pressure.
There are several categories of check valves to choose from, depending on the application in which they’re used. Each type has a different way of opening the valve when flow is progressing in the required direction or closing the valve when back pressure is present. One type is a silent check valve that uses a spring-assisted poppet to close the valve and prevent backflow. A swing check valve that uses a disc closure design to ensure fluid or gas moves in one direction. Like the name, a ball check valve employs a ball to control flow by moving up or down. Other valve types include lift, duckbill, diaphragm and foot check valves, among others. Check valves are made from plastic or metal, such as stainless steel or bronze.
While most check valves use an O-ring to seal the valve, Strataflo uses a proprietary fully molded rubber seal. Molded around steel for added strength, the Strataflo poppet lasts longer than traditional seals.
What are common uses of check valves?
Check valves are used in a wide range of products, from industrial to domestic applications. If a liquid, gas or steam is being moved through a pipe, you’ll likely find a check valve in operation, ensuring the material is moving in the desired direction. These devices are used to protect equipment from backflow, which can cause damage, system shutdowns and costly repairs.
One of the most common uses of check valves is in pump systems where they keep fluids, gases or steam flowing in one direction. In the oil and gas industry, large check valves prevent the flow from reversing. They are often installed on the discharge end of the pump, where they automatically shut off the flow after the pump is disengaged, preventing the system from draining.
In industrial processes where gas and another material, such as an oxidizer, are mixed together in one stream, check valves are used to ensure the gas cylinders remain separate, adding a level of safety.
Check valves help maintain sanitary conditions when used in domestic applications. In sewer pipes, they allow wastewater to exit a structure while preventing it from re-entering in the event of a backup in the sewer system. Dishwashers and clothes washers use check valves to prevent contaminated water from re-entering the domestic water supply.
Water pump systems use check valves to maintain pressure when the pump is off, as well as prevent backflow. For example, on a home water heater, a check valve will prevent hot water from returning to the cold inlet waterline when there is a drop in pressure on the cold side. HVAC systems in large buildings also have check valves to control the flow of coolant through multiple floors.
Whether used in domestic or industrial applications, check valves play an important role in safeguarding equipment and maintaining performance. Discover more about check valves here.