Mercer valve was founded by Wesley Taylor with his Auto Seat Technology® patent for pressure relief valves.

Mercer’s first valve line was the 8100 Series introduced in 1985. Auto Seat Technology® is incorporated in the valve design, allowing it to pop and reseat time and time again. Unlike the competition, the valve has a soft seat design with a fully guided disk and spring to help the valve have a longer life.

With the introduction of our 8100 Series, Mercer Valve started a VR Certified Valve Repair Division. The repair division repairs all relief valve manufacturers and also has mobile units for on-site repair and testing. In addition to the VR shop, we have added an “ANSI” shop, repairing ball valves, orbit valves, gate valves, as well as many other kind of valves.

The 8700 Series was Mercer Valve’s next endeavor. This valve has the same guiding system as the 8100 Series, but incorporates a hard seat. The guiding system increases the repeatability of the valve opening and closing.


Mercer’s 9100 Series, the industrial pressure relief valve, was introduced in 1991. The 9100 Series was developed to handle industrial gases and liquids, while continuing to use the proven design of Auto Seat Technology®. The 9100 Series also provides more options for the customer including different soft seat and seal materials, threaded and flanged connections, and sizes ranging from 1/2“x1” to 4”x6”.

In 1995, Mercer Valve added the 9100 Series Model 20 to their product line. This valve line is used for high pressure service up to 8700 psig set pressure.

Mercer Valve entered the pilot operated relief valve market with the 9500 Series. The 9500 Series includes API Orifice Sizes from “D” through “T” and Full Bore Orifices up to 8 inches. Mercer’s 9500 Series includes both a snap action pilot and a modulating action pilot. The modulating pilot is unlike any in the industry, having full modulation throughout the over pressure range. Continuing in the Mercer tradition, the 9500 Series has a long life due to the usage of Auto Seat Technology®.

With the growth and success of our valve lines, Mercer Valve moved in a new building housing the home office, repair division, and manufacturing department. The facilities also include an expanded fully functioning flow lab. Mercer Valve has always strived to be safe minded and engineer driven. The expanded flow lab has increased testing and enabled further research and development.


In 2000, Mercer opened a Houston Branch to help service our Houston customers more efficiently. The Houston Branch assembles valves keeping lead times at a minimum. The Houston Branch is also a VR certified repair shop.

A few years later, Mercer opened a location in Calgary, AB, Canada to support our Canadian customers. Mercer Valve also opened a new repair center in Oklahoma City to accommodate the increasing repair business. The new repair center offers a larger area for the repair of other oilfield equipment including glycol pumps, chemical pumps, ball valves, gate valves, orbits valves, etc.