Tuesday, August 19, 2014

Introduction to the Instrumentation Ball Valve

instrumentation ball valves
Instrumentation Ball Valves
(DK-Lok)
Instrumentation ball valves are used in a wide variety of industrial, environmental, pharmaceutical, semiconductor and "clean applications. These valves are designed to handle wild fluctuations in ambient temperatures and operate at high pressures.

Also referred to as "one-piece" instrumentation ball valves, they are an excellent choice for cold ambient conditions down to -65 deg. F as well as handling heated gases and fluids up to 300 deg. F.

What defines the the ball valve as an "instrument ball valve" is the 1 piece ball and stem component. General service, industrial ball valves are designed with a 2 pc. ball and stem arrangement, where the ball "floats" in the process medium and uses the downstream pressure to seat.

Instrumentation ball valves historically were troubled when installed in low ambient temperatures. Cold environments below -50F would cause stem leakage.

Alternative packing materials where developed allowing working temperatures down to -65F but those packing materials were limited on the upper temperature range to 150 deg. F.

Ultimately, new packing was developed to handle -65 F to 300F, which covers a very wide range of application.

Instrument ball valves are available in brass and stainless steel. Their end connections are typically from 1/8" T to 3/4" T (compression tube connections) and from 1/8 NPTF to 1/2" NPTF (pipe sizes ). Many different types of end connections are available.

Instrumentation ball valves are available in the following configurations: 2-way, straight or angle; 3-way switching without any directional requirements; and a 4-way design.