Functions And Features Of A Stop-Check Valve

It takes a while to figure out that not all valves are created equal.

There are valves that are appropriate for specific tasks, there are other valves that can be used for more generic reasons. 

And, there are valves that are essential for protection and can save the system from an imminent collapse like commercial shutoff valves.

One of those valves is the stop-check valve, which can provide an added layer of protection to your boilers and other equipment.

So keep on reading to know all about what a stop-check valve is, as well as its functions and features.

What Is a Stop-Check Valve?

In short, a stop-check valve is a modified version of the standard global stop valve, which comes with a valve stem attached to the globe disc.

However, with a stop-check valve, the stem head isn’t attached in the globe disc. As a matter of fact, it basically floats.

Stop-Check Valves: Usage and Features

This valve has two primary purposes. The first purpose is acting as a globe valve and isolating —or regulating— the flow. The second purpose is acting as a check valve with the ability to prevent reverse flow.

Thus, in its capacity is a globe valve; the stop-check valve starts or stops the flow of the media as well as automatically close if there is a loss in pressure, which brings us to its check-valve qualities. 

This prevents backflow, which if left unattended, can damage a variety of equipment like pumps and boilers. 

Stop-Check Valves: Areas of Usage

Traditionally, you’d see stop-check valves commonly used in power plants, as well as applications like boiler circulation, turbine cooling, steam generation, and safety systems.

In addition, stop-check valves can be used where piping designers want to get the dual benefits of both a globe and check value. 

Stop-Check Valve Designs

These types of valves come in two basic designs: the T pattern and the Y pattern.

For the T pattern, we see a stem that is perpendicular to the pipeline. This design allows the internal disc the freedom to move up and down in a vertical direction in the valve.

Moreover, the weight of the disc aids in closing quickly by providing minimal reverse velocity as the valve closes. But, due to its weight, it needs a higher flow velocity to get the valve to open fully, which can lead to value pressure loss.

Furthermore, we have a new design, which is the Y pattern. This pattern has a stem and disc which are angled at 30 to 45 degrees.

It’s commonly seen on top of boilers and comes in a straightway or an angled flow path. This provides a lower full-open flow velocity. 

Ready to Learn More About Valves?

While learning all about the functions of a stop-check valve is a great start to selecting the right valves for your machines, there is still so much more to learn before truly knowing what makes valves tick.

Whether you’re trying to decipher valve hieroglyphs or comparing stainless steel valve grades, make sure to check out our news section for the latest on all things valves and fittings.