- Settore: Industrial valves
- Number of terms: 3113
- Number of blossaries: 0
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A term used to describe certain standardized testing procedures for control valves with a flow coefficient greater then 0. 1 (C<sub>v</sub>). These procedures are outlined in ANSI Standard d B16. 104-1976, which gives specific tests and tolerances for six seat leakage classifications. It should be remembered that these tests are used to establish uniform acceptance standards for manufacturing quality and are not meant to be used to estimate leakage under actual working conditions. Nor should anyone expect these leakage rates to be maintained after a valve is placed in service. There is no standard test for self-contained regulators at this time. Note! You will see many instances where regulators are specified using the above criteria.
Industry:Industrial valves
A term used to describe the desired failure position of a control valve. It could fail-closed, fail-open, or fail-in-place. For a spring-return operator to fail-in-place usually requires the use of a lock-up valve.
Industry:Industrial valves
A term used to describe the ability of an actuator to stay at the same percent of travel it was in when it lost its air supply. On SPRING RETURN actuators this is accomplished by means of a lock-up valve. On piston actuators a series of compressed air cylinders must be employed.
Industry:Industrial valves
A term used to describe a type of valve flow characteristic where for equal increments of valve plug travel the change in flow rate with respect to travel may be expressed as a constant percent of the flow rate at the time of the change. The change in flow rate observed with respect to travel will be relatively small when the valve plug is near its seat and relatively high when the valve plug is nearly wide open.
Industry:Industrial valves
A term used to describe a threaded connection located on the bonnet of a valve that allows for the detection of leakage of the process fluid past the packing area.
Industry:Industrial valves
A term used to describe a linear or globe style valve that uses a reverse action plug and stem arrangement. The plug is located below the seat ring. When the plug is pushed down, the plug moves away from the seat, and the valve opens.
Industry:Industrial valves
A term used to describe a linear or globe style valve that uses a direct acting plug and stem arrangement. The plug is located above the seat ring. When the plug is pushed down, the plug contacts the seat, and the valve closes. Note! Most control valves are of this type.
Industry:Industrial valves
A term that describes a procedure for reducing the leakage rate on metal-to-metal seated valves and regulators. The plug and seat are lapped together with the aid of an abrasive compound in an effort to establish a better seating surface than would normally be achieved by means of machining.
Industry:Industrial valves
A switch that is linked to the valve stem to detect a single, preset valve stem position. Example: Full open or full closed. The switch may be pneumatic, hydraulic, or electric.
Industry:Industrial valves
A style of mounting the disc or ball on the valve shaft or stub shaft with two bushings diametrically opposed.
Industry:Industrial valves
