Keep Fluid Lines in Check with Check Valves

by Joanna Dykhuis, IQS Editor

Everyone knows the sound of a heart beat. Children often describe it as making a “thump thump” sound while science teachers and medical professionals use the onomatopoeia “lub dub.” Another possible sound is a whistling or swishing which indicates a possible heart murmur, the result of a heart valve not operating properly. Because the heart beats over 2.5 billion times in an average lifespan, heart murmurs are not uncommon. A heart valve is essentially a check valve, a device that opens and closes to allow the flow of a fluid—in this case, blood—in one direction. Though heart valves are the most critical check valve on earth, these helpful little devices have many uses outside the body.

Mechanical Check Valves

Photo courtesy of Check-All Valve Manufacturing Co.

Check valves are used widely in many manufacturing and industrial processes. They are also known as non return valves because they eliminate backflow for liquid, air or gas. Mechanical check valves are placed in pipelines and are self-activating meaning that, like a heart, they react to the flow of fluid and do not require an outside force to operate. When check valves are used to control the pressure, they are called relief valves because they relieve excess pressure from the system. Hearts do not have relief valves because a closed system is necessary to maintain blood pressure.

Relief Valves Ball Check Valves Check Valves

Photos courtesy of Hy-Lok USA, Inc. and Circor Aerospace, Inc.

Because of the importance and usefulness of check valves, they are available in many different styles. Though the heart has four valves, there are many more kinds of mechanical valves on the market including ball check valves, lift check valves, swing check valves, wafer check valves, double check valves and more. Water heaters, indoor plumbing, flowmeters, boilers, industrial mixers, water treatment plants, food processors, metering pumps, dishwashers and other pieces of equipment and machinery use check valves to ensure safety and control over fluid lines.

Mechanical Check Valves Wafer Check Valves

Photos courtesy of Check-All Valve Manufacturing Co.

Another common usage of check valves is found in your garage. When driving makes your heart beat faster, the check valves in your car are working too. Check valves in vehicles are used to control the flow of coolants, exhaust, pressurized air and other liquids or gases. Through the use of these valves, air conditioners are able to keep the driver and passenger cool, brakes are able to slow or stop the car and dangerous exhaust fumes do not waft up into the interior of the car but are instead expelled through the muffler. Some check valves are plastic while others are made from polyvinyl chloride, or PVC. Brass check valves are the most widely used because of the metal’s durability and strength.

Plastic Check Valve Check Valve Check Valve

Photos courtesy of Anderson Metals Corp. and Circor Aerospace, Inc.

The use of check valves is essential for many. Without these simple devices, many daily activities would be difficult and unsafe because of backflow and pressure levels. Check valves ensure that liquids and gases flow in only one direction at acceptable rates. They are almost as important to industrial processes as our heart’s check valves are to us.

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