Abnormality detection/suppression system for a valve apparatus
First Claim
1. In a valve apparatus including a valve casing which defines therein a fluid passage having first valve seats mounted therein, a valve body movable between a fully open position and a fully closed position for selectively opening or closing said fluid passage to fluid flow thru said valve apparatus, said valve body having second valve seats mounted thereon and adapted to selectively engage with said first valve seats in a fluid-tight manner in a leak-free valve apparatus, a stem having one end portion coupled to said valve body integrally therewith and the other end portion extending through a gland/packing assembly installed around said valve stem in said valve casing to the exterior thereof, and a driving unit operatively coupled to said stem at a location externally of said valve casing so as to move said valve body between the two extreme, intended modes of said fully open position and said fully closed position, or in the event of a leak condition that said valve body assumes a position only partially fully-open or partially fully-closed, respectively, to move said valve body towards said fully-open position or fully-closed position;
- an abnormality detection and suppression system, characterized in that a vibration sensor, a temperature sensor and a strain sensor are disposed internally of said stem at a portion thereof which is located outside of said valve casing when said valve body is intentionally moved to said fully closed position, and that a mini-computer control unit is disposed externally of said valve casing and adapted to receive output signals from said vibration sensor, said temperature sensor and said strain sensor, wherein when said valve body should occupy the presumed position corresponding to the intended said fully closed position, substantially a partially fully-closed position, said control unit responds to the output signal of said vibration sensor indicating occurrence of vibration brought abut by leakage passing through the presumedly sealingly-engaged said first and second valve seats to thereby actuate and control said driving unit such that said valve body is further urged and driven in the valve closing direction towards the said fully closed position by means of said stem while monitoring simultaneously a load applied to said stem with said strain sensor until substantially no vibration is detected by said vibration sensor, thereby indicating cessation of the prior leak condition at said valve seats; and
whereas when said temperature sensor detects a temperature change due to leakage flow in the state in which said valve body is disposed to occupy the assumed position corresponding to the intended said fully open position, it releases an output signal that triggers a leakage failure condition in the control unit, whereupon said control unit responds to the output signal of said temperature sensor indicating occurrence of leakage through said gland/packing assembly to thereby actuate said driving unit such that said valve body is further driven in the valve opening direction towards said fully open position by means of said stem while monitoring simultaneously a load applied to said stem with said strain sensor until said temperature change and output signal substantially disappear, thereby also indicating cessation of the prior leak condition in said valve apparatus.
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0 Petitions
Accused Products
Abstract
Provision of an abnormality detection and suppression system for a valve apparatus, which is capable of detecting abnormal states such as leakage through valve seats or a gland/packing assembly and coping with the abnormality while ensuring protection for the valve apparatus by controlling a driving unit for a valve stem on the basis of information as detected, by means of a vibration sensor, a temperature sensor and a strain sensor are disposed internally of a valve stem 4 at a portion thereof which lies outside of a valve casing of the valve apparatus. When vibration of the valve stem brought abut by leakage through valve seats is detected by the vibration sensor in a fully closed state of the valve apparatus, a valve body thereof is driven further in the valve closing direction by a driving unit 13 controlled by a control unit, both being disposed externally of the valve casing, until the leakage and thus the vibrations disappear while monitoring simultaneously a load applied to the stem by the strain sensor. On the other hand, when a temperature change of the stem is detected by the temperature sensor in the fully open state of the valve apparatus, the control unit decides that the temperature change is due to leakage through a gland/packing assembly 12 of the valve apparatus to thereby control the driving unit so that the stem is driven to move the valve body in the valve opening direction while monitoring simultaneously a load applied to the stem until the change in the temperature is canceled out.
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Citations
7 Claims
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1. In a valve apparatus including a valve casing which defines therein a fluid passage having first valve seats mounted therein, a valve body movable between a fully open position and a fully closed position for selectively opening or closing said fluid passage to fluid flow thru said valve apparatus, said valve body having second valve seats mounted thereon and adapted to selectively engage with said first valve seats in a fluid-tight manner in a leak-free valve apparatus, a stem having one end portion coupled to said valve body integrally therewith and the other end portion extending through a gland/packing assembly installed around said valve stem in said valve casing to the exterior thereof, and a driving unit operatively coupled to said stem at a location externally of said valve casing so as to move said valve body between the two extreme, intended modes of said fully open position and said fully closed position, or in the event of a leak condition that said valve body assumes a position only partially fully-open or partially fully-closed, respectively, to move said valve body towards said fully-open position or fully-closed position;
- an abnormality detection and suppression system, characterized in that a vibration sensor, a temperature sensor and a strain sensor are disposed internally of said stem at a portion thereof which is located outside of said valve casing when said valve body is intentionally moved to said fully closed position, and that a mini-computer control unit is disposed externally of said valve casing and adapted to receive output signals from said vibration sensor, said temperature sensor and said strain sensor, wherein when said valve body should occupy the presumed position corresponding to the intended said fully closed position, substantially a partially fully-closed position, said control unit responds to the output signal of said vibration sensor indicating occurrence of vibration brought abut by leakage passing through the presumedly sealingly-engaged said first and second valve seats to thereby actuate and control said driving unit such that said valve body is further urged and driven in the valve closing direction towards the said fully closed position by means of said stem while monitoring simultaneously a load applied to said stem with said strain sensor until substantially no vibration is detected by said vibration sensor, thereby indicating cessation of the prior leak condition at said valve seats; and
whereas when said temperature sensor detects a temperature change due to leakage flow in the state in which said valve body is disposed to occupy the assumed position corresponding to the intended said fully open position, it releases an output signal that triggers a leakage failure condition in the control unit, whereupon said control unit responds to the output signal of said temperature sensor indicating occurrence of leakage through said gland/packing assembly to thereby actuate said driving unit such that said valve body is further driven in the valve opening direction towards said fully open position by means of said stem while monitoring simultaneously a load applied to said stem with said strain sensor until said temperature change and output signal substantially disappear, thereby also indicating cessation of the prior leak condition in said valve apparatus. - View Dependent Claims (2, 3, 4, 5, 6)
- an abnormality detection and suppression system, characterized in that a vibration sensor, a temperature sensor and a strain sensor are disposed internally of said stem at a portion thereof which is located outside of said valve casing when said valve body is intentionally moved to said fully closed position, and that a mini-computer control unit is disposed externally of said valve casing and adapted to receive output signals from said vibration sensor, said temperature sensor and said strain sensor, wherein when said valve body should occupy the presumed position corresponding to the intended said fully closed position, substantially a partially fully-closed position, said control unit responds to the output signal of said vibration sensor indicating occurrence of vibration brought abut by leakage passing through the presumedly sealingly-engaged said first and second valve seats to thereby actuate and control said driving unit such that said valve body is further urged and driven in the valve closing direction towards the said fully closed position by means of said stem while monitoring simultaneously a load applied to said stem with said strain sensor until substantially no vibration is detected by said vibration sensor, thereby indicating cessation of the prior leak condition at said valve seats; and
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7. A stem assembly for a valve with an associated valve casing and valve body, comprising a stem passing therethru having one end portion coupled integrally to a valve body of said valve having a signal wire passage disposed thru said stem for electrical interconnection routing of conductive signal wires and having the said other end portion provided with terminals for electrical connection, wherein a temperature sensor, a vibration sensor and a strain sensor are disposed internally of said stem in a portion thereof lying outside of a valve casing of said valve when said valve body is at a fully closed position of said valve, with said temperature sensor, said vibration sensor and said strain sensor being electrically connected via said conductive signal wires to said terminals, respectively.
Specification