Instrument Valves: The Difference Between a Rotating One Piece Stem and a Non-Rotating Two Piece Stem

Process instrument valves are used with devices such as pressure measurement transmitters, gauges, and switches to isolate the device from the process media for replacement, calibration, and maintenance. Instrument valves are combined together and assembled into block and bleed manifolds combing multiple valves into a single body configuration, with each valve having a separate external connection and a common internal connection.

A critical component to the instrument valve is the valve stem. The stem positions the stem point into the orifice and against the valve seat to control flow and to isolate the process.

INSTRUMENT VALVE STEM TYPES

A rotating one piece valve stem rotates and translates along its axis as it is being driven axially into the orifice. The rotational motion of a one piece stem can produce friction as the stem interacts with the seating area, which could result in galling at the seating surface. This is less of an issue in a soft seat valve or if the media provides lubrication.

A non-rotating two piece stem tip rotates independently from the stem and stops rotating as it is driven axially against the orifice sealing surface while the stem continues its rotational and axial movement.

For more information about process instrumentation valves and valve manifolds, contact Advance Instruments. Call them at (888) 388-6446 or visit their web site at https://advanceinstruments.com.

NOSHOK Needle and Manifold Valves

NOSHOK's patented needle and manifold valves provide an innovative design, featuring a unique body-to-bonnet, metal-to-metal seal that significantly increases the pressure range of the valve without compromising the flow coefficient. The design also assists in maintaining the integrity of the bonnet threads by segregating them from the process media.

Built for maximum durability and performance in the toughest applications, NOSHOK valves are available with Zinc-Nickel plating, which provides one of the highest levels of corrosion resistance available. Additionally, all NOSHOK valves are 100% helium leak tested to 1 x 10-4 ml/s for guaranteed performance and reliability.

Valve models incorporating this patented design include the 100 Series hard seat mini valves, 800/850 Series bleed valves, all 2-valve block and bleed valves along with 5-valve manifolds.

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LEARN MORE AND DOWNLOAD THE NOSHOK VALVE PRODUCT SOLUTIONS CATALOG HERE

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For more information on all NOSHOK products, contact Advance Instruments by calling  (888) 388-6446 or by visiting https://advanceinstruments.com.