Chemical analysis of water and steam samples in modern power generation plants requires precise control of flow and pressure. However, high-pressure reduction needs can present sampling problems. The patented Sentry VREL is a valve specifically designed to solve unique high-pressure sampling issues. The Sentry VREL consists of two stainless steel tubes joined to a large tube or barrel.

A tapered rod assembly is inserted into precision holes in the barrel. The high pressure fluid enters, flows past one rod, turns and flows past the other rod, and then out. Pressure drop is a function of the length of the rods inserted into the barrel. The pressure is reduced smoothly under laminar flow conditions, minimizing dissociation of any components through discontinuous pressure drops. The rod position is controlled externally by turning the knob, and can be adjusted while sample is flowing. If blockage occurs, the rods can be retracted so system pressure can blow the solid matter through.

Benefits

• Adjustable rod-in-tube type design allows for variable pressure drop and flow control
• The VREL allows precise control of flow and pressure without valve erosion or fluid dissociation
• All wetted parts are fabricated from 316 stainless steel
• Rated to 5000 psig at 300ºF (345 barg at 149ºC), and 7803 psig (538 bar) for supercritical power plant applications
• The VREL is cleanable in place, "in situ", by retracting the rods without disconnecting or isolating the sample line