Pressure reducing valves, or PRVs, play an important role in keeping people and equipment running smoothly. Because steam typically enters a system at a higher pressure than what’s needed at the point of use, PRVs are designed to control or reduce the pressure for the application. Otherwise, steam will build up and damage fixtures, rupture pipes, or even cause fires. For this reason, steam systems may require multiple PRVs for optimal functioning, safety, and efficiency throughout the entire facility.

Understanding Different Types of PRVs

There are several different types of PRVs, with different applications.

• Direct Acting PRVs. Direct acting PRVs are self-contained and simple. They don’t require external sensing lines, so they are economical to operate. Designed for low- to moderate flows, direct acting PRVs have accuracy rates of +/- 10%.
• Internally Piloted Piston Operated PRVs. With two valves in one unit, an internally piloted, piston operated PRV is similar in design to a direct acting PRV and does not require an external sensing line. However, this type of PRV uses inlet pressure to open a large main valve. Because of this difference, it boasts both greater per-line capacity and a greater accuracy rate (+/- 5%) than direct acting PRVs.
• Externally Piloted PRVs. Where the internally piloted PRV relies on a piston operator to open the main valve, the externally piloted type uses double diaphragms to open the main line. This allows them to handle a greater capacity than other types of PRVs. They are also more sensitive to pressure changes, helping increase accuracy (+/- 1%).

When deciding what types of PRVs you need, you should consider the maximum supply pressure, downstream pressure desired, flow range, and temperature.

No Matter What Type of PRV You Need, Calpacific Can Help

At Calpacific, we specialize in helping businesses of all types choose and install PRVs designed to keep the business and it’s property, employees, and customers safe while creating cost efficiencies. Whether you need direct acting, internally piloted piston operated, externally piloted PRVs, or some combination of them, we stock a range of PRVs to fit your business’s needs.