WO2009072804A2 - Apparatus for detecting opening and closing of check valve - Google Patents

Apparatus for detecting opening and closing of check valve Download PDF

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Publication number
WO2009072804A2
WO2009072804A2 PCT/KR2008/007136 KR2008007136W WO2009072804A2 WO 2009072804 A2 WO2009072804 A2 WO 2009072804A2 KR 2008007136 W KR2008007136 W KR 2008007136W WO 2009072804 A2 WO2009072804 A2 WO 2009072804A2
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WO
WIPO (PCT)
Prior art keywords
point
place
magnetic field
magnetic
check valve
Prior art date
Application number
PCT/KR2008/007136
Other languages
French (fr)
Other versions
WO2009072804A3 (en
Inventor
Jang Bom Chai
Young Sun Kim
Original Assignee
M & D Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by M & D Co., Ltd. filed Critical M & D Co., Ltd.
Publication of WO2009072804A2 publication Critical patent/WO2009072804A2/en
Publication of WO2009072804A3 publication Critical patent/WO2009072804A3/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K37/00—Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K37/00—Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
    • F16K37/0025—Electrical or magnetic means
    • F16K37/0041—Electrical or magnetic means for measuring valve parameters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K35/00—Means to prevent accidental or unauthorised actuation

Definitions

  • the present invention relates to an apparatus for detecting opening and closing of a check valve. More particularly, the present invention relates to an apparatus for detecting opening and closing of a check valve in which it is accurately judged whether or not a point in time that the check valve is opened and a point in time that the check valve is closed, and it is accurately judged whether or not a valve disc of the check valve is correctly mounted in a valve seat in order to judge whether or not the check valve has been completely closed, when the check valve are opened and closed, to thereby correctly detect whether or not fluid leaks in the check valve and performance of the check valve is degraded, and to thus judge a correct replacement period of time of the check valve.
  • a check valve is installed on the way of a pipe through which fluid is transferred, and thus is used to make the fluid flow in one direction and prevent the fluid from flowing backward.
  • FIG. 1 is a longitudinal cross-sectional view of a general check valve.
  • the check valve includes a cylindrical main body 10, a valve disc 20, and a transfer portion 30.
  • the cylindrical main body 10 includes a seat body portion 3 in which a valve seat 1 is formed, and an inlet pipe 40 is connected to one side of the cylindrical main body 10, and a valve body portion 5 which is connected to an outlet pipe 50 which is connected to the other side of the cylindrical main body 10, to thereby form a flow path along which a flow of fluid that flows in the inlet pipe 40 is derived into the outlet pipe 50.
  • the valve disc 20 contacts the valve seat 1 air tightly in the inside of the cylindrical main body 10.
  • the transfer portion 30 is formed of a pivot pin which is formed in the cylindrical main body 10, to thereby make the valve disc 20 pivoted and to thus make the valve disc 20 pivotally move to an opened position and a closed position.
  • FIGS. 2 and 3 are cross-sectional views showing a conventional apparatus for detecting opening and closing of a check valve using ultrasonic waves in order to detect whether a valve disc 20 of the check valve is at an opened position or a closed position, respectively.
  • an ultrasonic probe 60 is installed on the outer circumferential surface of the lower end of the main body 10. Then, an ultrasonic signal is generated into the main body 10 from the ultrasonic probe 60, and the generated ultrasonic signal reaches the valve disc 20 using fluid in the check valve as a medium.
  • the ultrasonic signal having reached the valve disc 20 is reflected from the valve disc 20, to then be returned to the ultrasonic probe 60.
  • the ultrasonic probe 60 measures a time which is taken until the reflected ultrasonic signal is returned to the ultrasonic probe 60 after the ultrasonic probe 60 has been generated from the ultrasonic probe 60, to thus judge whether the valve disc 20 is at an opened position or a closed position.
  • the conventional apparatus for detecting opening and closing of a check valve has defective points that it cannot be accurately judged whether a point in time at which the check valve is opened and a point in time at which the check valve is closed, and it cannot be accurately judged whether or not a valve disc is correctly mounted in a valve seat.
  • an object of the present invention to provide an apparatus for detecting opening and closing of a check valve, which detects an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby accurately judge a point in time when the check valve is opened or closed according to change of the detected induced voltage, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
  • an apparatus for detecting opening and closing of a check valve which detects change of an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby detect whether or not the valve disc is correctly mounted in a valve seat to thus accurately diagnose whether or not fluid in the check valve leaks, or judge performance of the check valve, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
  • a main body which comprises a seat body portion in which a valve seat is formed, and an inlet pipe is connected to one side of the main body, and a valve body portion which is connected to an outlet pipe which is connected to the other side of the main body, to thereby form a flow path along which a flow of fluid that flows in the inlet pipe is derived into the outlet pipe;
  • a magnetic field generator that generates a magnetic field forming a closed loop that begins at a first point in place on the outer circumferential surface at one side of the seat body portion, passes through the valve disc, and arrives at a second point in place on the outer circumferential surface at the other side of the seat body portion;
  • an opening and closing detector which detects change of a magnetic flux in the magnetic field which has been generated from the magnetic field generator according to a position at which the valve disc moves, to thereby judge whether the check valve is opened or closed
  • the magnetic field generator comprises: a main magnetic field generator whose one end is connected to the first point in place and other end is connected to the second point in place, to thus generate a magnetic field from the first point in place to the second point in place; and a magnetic field interceptor which blocks the magnetic flux of the magnetic field so that the magnetic flux of the magnetic field generated from the main magnetic field generator is not generated toward the outer circumferential surface of the seat body portion.
  • an apparatus for detecting opening and closing of a check valve detects an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby accurately judge a point in time when the check valve is opened or closed according to change of the detected induced voltage, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
  • the apparatus for detecting opening and closing of a check valve detects change of an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby detect whether or not the valve disc is correctly mounted in a valve seat to thus accurately diagnose whether or not fluid in the check valve leaks, or judge performance of the check valve, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
  • FIG. 1 is a longitudinal cross-sectional view of a general check valve
  • FIGS. 2 and 3 are cross-sectional views showing a conventional apparatus for detecting opening and closing of a check valve using ultrasonic waves in order to detect whether a valve disc of the check valve is at an opened position or a closed position, respectively;
  • FIGS. 4 and 5 are longitudinal cross-sectional views showing a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted, respectively;
  • FIG. 6 is a cross-sectional view showing a seat body portion in a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted;
  • FIG. 7 is a waveform graph of an induced voltage when a valve disc is opened or closed in an opening and closing detector applied to an apparatus for detecting opening and closing of a check valve according to the present invention
  • FIG. 8 is a waveform graph showing a magnetic saturation characteristic in the inner wall of a seat body portion at a third point in place and a fourth point in place by a first magnetic flux interceptor and a second magnetic flux interceptor, respectively;
  • FIG. 9 is a waveform graph showing a magnetic saturation characteristic in a main body and a second core and a third core of a check valve to which an apparatus for detecting opening and closing of the check valve according to the present invention is applied.
  • FIGS. 4 and 5 are longitudinal cross-sectional views showing a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted, respectively.
  • FIG. 6 is a cross-sectional view showing a seat body portion in a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted.
  • FIG. 7 is a waveform graph of an induced voltage when a valve disc is opened or closed in an opening and closing detector applied to an apparatus for detecting opening and closing of a check valve according to the present invention.
  • FIG. 8 is a waveform graph showing a magnetic saturation characteristic in the inner wall of a seat body portion at a third point in place and a fourth point in place by a first magnetic flux interceptor and a second magnetic flux interceptor, respectively.
  • FIG. 9 is a waveform graph showing a magnetic saturation characteristic in a main body and a second core and a third core of a check valve to which an apparatus for detecting opening and closing of the check valve according to the present invention is applied.
  • the check valve opening and closing detecting apparatus includes: a magnetic field generator 100 that generates a magnetic field forming a closed loop that begins at a first point in place (Pl) on the outer circumferential surface at one side of a seat body portion 3, passes through a valve disc 20, and arrives at a second point in place (P2) on the outer circumferential surface at the other side of the seat body portion 3, in which the second point in place (P2) has a phase opposing that of the first point in place (Pl); and an opening and closing detector 200 which detects change of a magnetic flux in the magnetic field which has been generated from the magnetic field generator 100 according to a position at which the valve disc 20 moves, to thereby judge whether the check valve is opened or closed.
  • a magnetic field generator 100 that generates a magnetic field forming a closed loop that begins at a first point in place (Pl) on the outer circumferential surface at one side of a seat body portion 3, passes through a valve disc 20, and arrives at a second point in place (P2) on the outer circumfer
  • the magnetic field generator 100 includes: a main magnetic field generator 110 whose one end is connected to the first point in place (Pl) and other end is connected to the second point in place (P2), to thus generate a magnetic field from the first point in place (Pl) to the second point in place (P2); and a magnetic field interceptor 120 which blocks the magnetic flux of the magnetic field so that the magnetic flux of the magnetic field generated from the main magnetic field generator 110 is not generated toward the outer circumferential surface of the seat body portion 3.
  • the main magnetic field generator 110 includes: a first power supply 111 that supplies a first voltage (Vl); a first core 113 whose one end contacts the first point in place (Pl), and whose other end contacts the second point in place (P2); and a first coil 115 which is wound around the outer circumferential surface of the first core 113 and which generates a magnetic field into the inside of the first core 113 by the first voltage (Vl).
  • Vl first power supply 111 that supplies a first voltage (Vl); a first core 113 whose one end contacts the first point in place (Pl), and whose other end contacts the second point in place (P2); and a first coil 115 which is wound around the outer circumferential surface of the first core 113 and which generates a magnetic field into the inside of the first core 113 by the first voltage (Vl).
  • the magnetic field interceptor 120 forms magnetic saturation magnetic fields (MSl and MS2) having a magnetic saturation state, respectively in the inner wall of the seat body portion 3, except for the first point in place (Pl) and the second point in place (P2).
  • the magnetic field interceptor 120 includes: a first magnetic flux interceptor 120a that generates a first magnetic saturation magnetic field (MSl) having a magnetic saturation state in the inner wall of a third point in place (P3) on the outer circumferential surface of the seat body portion 3, except for the first point in place (Pl) and the second point in place (P2); and a second magnetic flux interceptor 120b that generates a second magnetic saturation magnetic field (MS2) having a magnetic saturation state in the inner wall of a fourth point in place (P4) on the outer circumferential surface of the seat body portion 3, in which the fourth point in place (P4) has a phase opposing that of the third point in place (P3).
  • MSl magnetic saturation magnetic field
  • P3 third point in place
  • the first magnetic field interceptor 120a includes: a second power supply 121a that supplies a second voltage (V2); a second core 123a whose one end contacts one side of the third point in place (P3), and whose other end contacts the other side of the third point in place (P3); and a second coil 125a which is wound around the outer circumferential surface of the second core 123a and which generates a magnetic field into the inside of the second core 123a by an electric current generated by the second voltage (V2), in which the first magnetic saturation magnetic field (MSl) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the third point in place (P3), when the second voltage (V2) is increased.
  • V2 second power supply 121a that supplies a second voltage (V2)
  • a second core 123a whose one end contacts one side of the third point in place (P3), and whose other end contacts the other side of the third point in place (P3)
  • a second coil 125a which is wound around the
  • the second magnetic field interceptor 120b includes: a third power supply 121b that supplies a third voltage (V3); a third core 123b whose one end contacts one side of the fourth point in place (P4), and whose other end contacts the other side of the fourth point in place (P4); and a third coil 125b which is wound around the outer circumferential surface of the third core 123b and which generates a magnetic field into the inside of the third core 123b by an electric current generated by the third voltage (V3), in which the second magnetic saturation magnetic field (MS2) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the fourth point in place (P4), when the third voltage (V3) is increased.
  • V3 third voltage
  • MS2 second magnetic saturation magnetic field
  • the second core 123a has a larger magnetic flux density than that of the main body
  • the third core 123b has a larger magnetic flux density than that of the main body 10 at the time of the magnetic saturation, so that magnetic saturation does not occur in the third core when the magnetic field generated in the inner wall of the seat body portion 3 at the fourth point in place (P4) is magnetically saturated by the increase of the third voltage (V3).
  • polarity of the first magnetic saturation magnetic field (MSl) having the magnetic saturation of the third point in place (P3) has the same polarity as that of the second magnetic saturation magnetic field (MS2) having the magnetic saturation of the fourth point in place (P4).
  • first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b may be implemented by using a permanent magnet in order to generate magnetic saturation magnetic fields, respectively.
  • the opening and closing detector 200 detects change of an induced voltage by change of a magnetic flux which is generated in the magnetic field generator 100, and judges whether the valve disc 20 is closed when the valve disc 20 is mounted in the valve seat 1, or judges whether the valve disc 20 is opened when the valve disc 20 is separated from the valve seat 1.
  • one end of the first core 113 is made to contact the first point in place (Pl) on the outer circumferential surface of one side of the seat body portion 3, and the other end of the first core 113 is made to contact the second point in place (P2) on the outer circumferential surface of one side of the seat body portion 3 having a phase opposing that of the first point in place (Pl), that is, a 180-degree phase difference. Accordingly, the first core 113 is made to contact the outer circumferential surface of the seat body portion 3.
  • the first core 113 is mounted on the outer circumferential surface of the seat body portion 3.
  • the first coil 115 is wound around the outer circumferential surface of the first core 113.
  • the first power supply 111 which supplies the first voltage (Vl) is connected to the first coil 115.
  • the first core 113 and the first coil 115 on the outer circumferential surface of the seat body portion 3 generates a magnetic field into the inner wall of the seat body portion 3.
  • the magnetic field interceptor 120 includes the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b.
  • the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b have an identical structure, and blocks the magnetic field generated from the main magnetic field generator 110 so that the magnetic field generated from the main magnetic field generator 110 does not flow in the inner wall of the outer circumferential surface of the seat body portion 3.
  • the first magnetic flux interceptor 120a is formed in the seat body portion 3 of the third point in place (P3) of the right-hand side that is clockwise from the first point in place (Pl), and the first magnetic flux interceptor 120b is formed in the seat body portion 3 of the fourth point in place (P4) of the left-hand side that is counterclockwise from the first point in place (Pl). That is, the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b generate the first and second magnetic saturation magnetic fields (MSl and MS2) having a magnetic saturation state, respectively, in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4).
  • the magnetic field that is generated from the main magnetic field generator 110 does not flow in the inner wall of the outer circumferential surface of the seat body portion 3, by the first and second magnetic saturation magnetic fields (MS 1 and MS2) having a magnetic saturation state, respectively, in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4), but flows into the second point in place (P2), via the valve disc 20 at the first point in place (Pl) which is another path.
  • the magnetic field that generated from the main magnetic field generator 110 forms a closed loop of the first point in place (Pl), the valve disc 20 and the second point in place (P2).
  • the magnetic flux of the magnetic field having a closed loop of the first point in place (Pl), the valve disc 20 and the second point in place (P2) varies at the moment when the valve disc 20 is mounted in the valve seat 1 and the check valve is closed, or at the moment when the valve disc 20 is separated from in the valve seat 1 and the check valve is opened. Therefore, as illustrated in FIG. 7, the opening and closing detector 200 detects change of magnetoresistance of a magnetic circuit according to change of the magnetic flux of the magnetic field and thus detects change of an induced voltage that is induced in the first coil 115. As described above, the opening and closing detector 200 detects change of the induced voltage and correctly judges when the check valve is closed or opened.
  • the opening and closing detector 200 can accurately detect whether or not the check valve is accurately opened at a time when the check valve should be opened, or whether or not the check valve is accurately closed at a time when the check valve should be closed, to thereby accurately diagnose performance of the check valve.
  • the opening and closing detector 200 does not only detect when the check valve is opened or closed as described above, but also detects an induced voltage according to an amount of change of a magnetic flux, since the magnetic flux of the magnetic field generated from the main magnetic field generator 110 is changed according to a position where the valve disc 20 moves, to thus judge to what a degree the valve disc 20 of the check valve is opened, and also accurately judge whether or not the valve disc 20 is correctly mounted in the valve seat 1.
  • the first magnetic flux interceptor 120a includes: a second power supply 121a that supplies a second voltage (V2); a second core 123a which contacts the third point in place (P3); and a second coil 125 a which is wound around the outer circumferential surface of the second core 123a and which generates a magnetic field into the inside of the second core 123a by an electric current generated by the second voltage (V2), in which the first magnetic saturation magnetic field (MSl) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the third point in place (P3), when the second voltage (V2) is increased.
  • V2 second power supply 121a that supplies a second voltage (V2)
  • a second core 123a which contacts the third point in place (P3)
  • a second coil 125 a which is wound around the outer circumferential surface of the second core 123a and which generates a magnetic field into the inside of the second core 123a by an electric current generated by the second voltage (V2), in which the first magnetic
  • the main body 10 of the check valve is formed of cast iron
  • the second core 123a is formed of a silicon steel plate having a larger magnetic flux density (T) than that of the case iron
  • the inner wall of the seat body portion 3 having the smaller magnetic flux density (T) than that of the second core 123a which is formed of a silicon steel plate is magnetically saturated earlier than the inside of the second core 123a, when the second voltage (V2) is continuously increased, and thus the first magnetic saturation magnetic field (MSl) is formed in the inner wall of the seat body portion 3 of the third point in place (P3).
  • Magnetic saturation means that a magnetic flux density (T) is saturated without increasing linearly in a magnetic substance, if the magnetic flux density (T) reaches a saturation point (A) on a magnetic saturation curved line even if an electric current is continuously increasingly applied to the second coil 125a as illustrated in FIG. 8. That is, the magnetic flux density (T) also increases lineally according to the electric current flowing in the second coil 125a if the electric current flowing in the second coil 125a increases until a magnetic field intensity reaches a point (B), but the magnetic flux density (T) does not increase any more and is saturated even if the electric current flowing in the second coil 125a is continuously increased if the magnetic field intensity reaches the point (B).
  • the second magnetic flux interceptor 120b is configured in the same manner as that of the first magnetic flux interceptor 120a. Accordingly, when the third voltage (V3) is increased, the second magnetic saturation magnetic field (MS2) is formed in the inner wall of the seat body portion 3 of the fourth point in place (P4).
  • the magnetic field that has been generated from the main magnetic field generator 110 is blocked by the first and second magnetic saturation magnetic fields (MS 1 and MS2) which have been formed in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4) by the first and second magnetic flux interceptors 120a and 120b, so that the magnetic field that has been generated from the main magnetic field generator 110 does not flow into the inner wall on the outer circumferential surface of the seat body portion 3.
  • first and second magnetic flux interceptors 120a and 120b may be implemented to generate a magnetic saturation magnetic field, respectively, a permanent magnet may be used for the first and second magnetic flux interceptors 120a and 120b, instead of an electromagnet, respectively.
  • a permanent magnet may be used for the first and second magnetic flux interceptors 120a and 120b, instead of an electromagnet, respectively.
  • the present invention can be applied to an apparatus for detecting opening and closing of a check valve in which it is accurately judged whether or not a point in time that the check valve is opened and a point in time that the check valve is closed, and it is accurately judged whether or not a valve disc of the check valve is correctly mounted in a valve seat in order to judge whether or not the check valve has been completely closed, when the check valve are opened and closed, to thereby correctly detect whether or not fluid leaks in the check valve and performance of the check valve is degraded, and to thus judge a correct replacement period of time of the check valve.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Magnetically Actuated Valves (AREA)
  • Check Valves (AREA)

Abstract

Provided is an apparatus for detecting opening and closing of a check valve, which includes a magnetic field generator that generates a magnetic field forming a closed loop that begins at a first point in place on the outer circumferential surface at one side of a seat body portion, passes through a valve disc, and arrives at a second point in place on the outer circumferential surface at the other side of the seat body portion, in which the second point in place has a phase opposing that of the first point in place; and an opening and closing detector which detects change of a magnetic flux in the magnetic field.

Description

Description
APPARATUS FOR DETECTING OPENING AND CLOSING OF
CHECK VALVE
Technical Field
[1] The present invention relates to an apparatus for detecting opening and closing of a check valve. More particularly, the present invention relates to an apparatus for detecting opening and closing of a check valve in which it is accurately judged whether or not a point in time that the check valve is opened and a point in time that the check valve is closed, and it is accurately judged whether or not a valve disc of the check valve is correctly mounted in a valve seat in order to judge whether or not the check valve has been completely closed, when the check valve are opened and closed, to thereby correctly detect whether or not fluid leaks in the check valve and performance of the check valve is degraded, and to thus judge a correct replacement period of time of the check valve. Background Art
[2] In general, a check valve is installed on the way of a pipe through which fluid is transferred, and thus is used to make the fluid flow in one direction and prevent the fluid from flowing backward.
[3] FIG. 1 is a longitudinal cross-sectional view of a general check valve.
[4] As illustrated in FIG. 1, the check valve includes a cylindrical main body 10, a valve disc 20, and a transfer portion 30. The cylindrical main body 10 includes a seat body portion 3 in which a valve seat 1 is formed, and an inlet pipe 40 is connected to one side of the cylindrical main body 10, and a valve body portion 5 which is connected to an outlet pipe 50 which is connected to the other side of the cylindrical main body 10, to thereby form a flow path along which a flow of fluid that flows in the inlet pipe 40 is derived into the outlet pipe 50. The valve disc 20 contacts the valve seat 1 air tightly in the inside of the cylindrical main body 10. The transfer portion 30 is formed of a pivot pin which is formed in the cylindrical main body 10, to thereby make the valve disc 20 pivoted and to thus make the valve disc 20 pivotally move to an opened position and a closed position.
[5] FIGS. 2 and 3 are cross-sectional views showing a conventional apparatus for detecting opening and closing of a check valve using ultrasonic waves in order to detect whether a valve disc 20 of the check valve is at an opened position or a closed position, respectively. As illustrated in FIGS. 2 and 3, in the case of the conventional apparatus for detecting opening and closing of a check valve, an ultrasonic probe 60 is installed on the outer circumferential surface of the lower end of the main body 10. Then, an ultrasonic signal is generated into the main body 10 from the ultrasonic probe 60, and the generated ultrasonic signal reaches the valve disc 20 using fluid in the check valve as a medium. The ultrasonic signal having reached the valve disc 20 is reflected from the valve disc 20, to then be returned to the ultrasonic probe 60. The ultrasonic probe 60 measures a time which is taken until the reflected ultrasonic signal is returned to the ultrasonic probe 60 after the ultrasonic probe 60 has been generated from the ultrasonic probe 60, to thus judge whether the valve disc 20 is at an opened position or a closed position.
[6] However, the conventional apparatus for detecting opening and closing of a check valve has defective points that it cannot be accurately judged whether a point in time at which the check valve is opened and a point in time at which the check valve is closed, and it cannot be accurately judged whether or not a valve disc is correctly mounted in a valve seat.
Disclosure of Invention
Technical Problem
[7] Therefore, to solve the above problems, it is an object of the present invention to provide an apparatus for detecting opening and closing of a check valve, which detects an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby accurately judge a point in time when the check valve is opened or closed according to change of the detected induced voltage, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
[8] It is also another object of the present invention to provide an apparatus for detecting opening and closing of a check valve, which detects change of an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby detect whether or not the valve disc is correctly mounted in a valve seat to thus accurately diagnose whether or not fluid in the check valve leaks, or judge performance of the check valve, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion. Technical Solution [9] To accomplish the above object of the present invention, according to an aspect of the present invention, there is provided an apparatus for detecting opening and closing of a check valve, the check valve opening and closing detecting apparatus comprising:
[10] a main body which comprises a seat body portion in which a valve seat is formed, and an inlet pipe is connected to one side of the main body, and a valve body portion which is connected to an outlet pipe which is connected to the other side of the main body, to thereby form a flow path along which a flow of fluid that flows in the inlet pipe is derived into the outlet pipe;
[11] a valve disc which contacts the valve seat 1 air tightly in the inside of the main body;
[12] a transfer portion which makes the valve disc move to thus make the valve disc move to an opened position and a closed position;
[13] a magnetic field generator that generates a magnetic field forming a closed loop that begins at a first point in place on the outer circumferential surface at one side of the seat body portion, passes through the valve disc, and arrives at a second point in place on the outer circumferential surface at the other side of the seat body portion; and
[14] an opening and closing detector which detects change of a magnetic flux in the magnetic field which has been generated from the magnetic field generator according to a position at which the valve disc moves, to thereby judge whether the check valve is opened or closed,
[15] wherein the magnetic field generator comprises: a main magnetic field generator whose one end is connected to the first point in place and other end is connected to the second point in place, to thus generate a magnetic field from the first point in place to the second point in place; and a magnetic field interceptor which blocks the magnetic flux of the magnetic field so that the magnetic flux of the magnetic field generated from the main magnetic field generator is not generated toward the outer circumferential surface of the seat body portion.
Advantageous Effects
[16] As described above, an apparatus for detecting opening and closing of a check valve, according to the present invention, detects an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby accurately judge a point in time when the check valve is opened or closed according to change of the detected induced voltage, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion.
[17] In addition, the apparatus for detecting opening and closing of a check valve, according to the present invention, detects change of an induced voltage according to change of a magnetic flux in a magnetic field where a closed loop is formed when the check valve is opened or closed, to thereby detect whether or not the valve disc is correctly mounted in a valve seat to thus accurately diagnose whether or not fluid in the check valve leaks, or judge performance of the check valve, in which the magnetic field generated by a magnetic filed generator which is mounted on the outer circumferential surface of a seat body portion forms the closed loop magnetic field through one side of the outer circumferential surface of the seat body portion, a valve disc, and the other side of the outer circumferential surface of the seat body portion. Brief Description of Drawings
[18] The above and/or other objects and/or advantages of the present invention will become more apparent by describing the preferred embodiments thereof in detail with reference to the accompanying drawings in which:
[19] FIG. 1 is a longitudinal cross-sectional view of a general check valve;
[20] FIGS. 2 and 3 are cross-sectional views showing a conventional apparatus for detecting opening and closing of a check valve using ultrasonic waves in order to detect whether a valve disc of the check valve is at an opened position or a closed position, respectively;
[21] FIGS. 4 and 5 are longitudinal cross-sectional views showing a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted, respectively;
[22] FIG. 6 is a cross-sectional view showing a seat body portion in a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted;
[23] FIG. 7 is a waveform graph of an induced voltage when a valve disc is opened or closed in an opening and closing detector applied to an apparatus for detecting opening and closing of a check valve according to the present invention;
[24] FIG. 8 is a waveform graph showing a magnetic saturation characteristic in the inner wall of a seat body portion at a third point in place and a fourth point in place by a first magnetic flux interceptor and a second magnetic flux interceptor, respectively; and
[25] FIG. 9 is a waveform graph showing a magnetic saturation characteristic in a main body and a second core and a third core of a check valve to which an apparatus for detecting opening and closing of the check valve according to the present invention is applied. Best Mode for Carrying out the Invention
[26] Hereinbelow, an apparatus for detecting opening and closing of the check valve according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. Like reference numerals denote like elements through the following embodiments.
[27] FIGS. 4 and 5 are longitudinal cross-sectional views showing a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted, respectively. FIG. 6 is a cross-sectional view showing a seat body portion in a check valve in which an apparatus for detecting opening and closing of the check valve according to the present invention is mounted. FIG. 7 is a waveform graph of an induced voltage when a valve disc is opened or closed in an opening and closing detector applied to an apparatus for detecting opening and closing of a check valve according to the present invention. FIG. 8 is a waveform graph showing a magnetic saturation characteristic in the inner wall of a seat body portion at a third point in place and a fourth point in place by a first magnetic flux interceptor and a second magnetic flux interceptor, respectively. FIG. 9 is a waveform graph showing a magnetic saturation characteristic in a main body and a second core and a third core of a check valve to which an apparatus for detecting opening and closing of the check valve according to the present invention is applied.
[28] As shown in FIGS. 4 to 7, an apparatus for detecting opening and closing of a check valve is provided according to a preferred embodiment of the present invention. The check valve opening and closing detecting apparatus according to the preferred embodiment of the present invention includes: a magnetic field generator 100 that generates a magnetic field forming a closed loop that begins at a first point in place (Pl) on the outer circumferential surface at one side of a seat body portion 3, passes through a valve disc 20, and arrives at a second point in place (P2) on the outer circumferential surface at the other side of the seat body portion 3, in which the second point in place (P2) has a phase opposing that of the first point in place (Pl); and an opening and closing detector 200 which detects change of a magnetic flux in the magnetic field which has been generated from the magnetic field generator 100 according to a position at which the valve disc 20 moves, to thereby judge whether the check valve is opened or closed.
[29] The magnetic field generator 100 includes: a main magnetic field generator 110 whose one end is connected to the first point in place (Pl) and other end is connected to the second point in place (P2), to thus generate a magnetic field from the first point in place (Pl) to the second point in place (P2); and a magnetic field interceptor 120 which blocks the magnetic flux of the magnetic field so that the magnetic flux of the magnetic field generated from the main magnetic field generator 110 is not generated toward the outer circumferential surface of the seat body portion 3.
[30] The main magnetic field generator 110 includes: a first power supply 111 that supplies a first voltage (Vl); a first core 113 whose one end contacts the first point in place (Pl), and whose other end contacts the second point in place (P2); and a first coil 115 which is wound around the outer circumferential surface of the first core 113 and which generates a magnetic field into the inside of the first core 113 by the first voltage (Vl).
[31] The magnetic field interceptor 120 forms magnetic saturation magnetic fields (MSl and MS2) having a magnetic saturation state, respectively in the inner wall of the seat body portion 3, except for the first point in place (Pl) and the second point in place (P2).
[32] The magnetic field interceptor 120 includes: a first magnetic flux interceptor 120a that generates a first magnetic saturation magnetic field (MSl) having a magnetic saturation state in the inner wall of a third point in place (P3) on the outer circumferential surface of the seat body portion 3, except for the first point in place (Pl) and the second point in place (P2); and a second magnetic flux interceptor 120b that generates a second magnetic saturation magnetic field (MS2) having a magnetic saturation state in the inner wall of a fourth point in place (P4) on the outer circumferential surface of the seat body portion 3, in which the fourth point in place (P4) has a phase opposing that of the third point in place (P3).
[33] The first magnetic field interceptor 120a includes: a second power supply 121a that supplies a second voltage (V2); a second core 123a whose one end contacts one side of the third point in place (P3), and whose other end contacts the other side of the third point in place (P3); and a second coil 125a which is wound around the outer circumferential surface of the second core 123a and which generates a magnetic field into the inside of the second core 123a by an electric current generated by the second voltage (V2), in which the first magnetic saturation magnetic field (MSl) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the third point in place (P3), when the second voltage (V2) is increased.
[34] In addition, the second magnetic field interceptor 120b includes: a third power supply 121b that supplies a third voltage (V3); a third core 123b whose one end contacts one side of the fourth point in place (P4), and whose other end contacts the other side of the fourth point in place (P4); and a third coil 125b which is wound around the outer circumferential surface of the third core 123b and which generates a magnetic field into the inside of the third core 123b by an electric current generated by the third voltage (V3), in which the second magnetic saturation magnetic field (MS2) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the fourth point in place (P4), when the third voltage (V3) is increased.
[35] The second core 123a has a larger magnetic flux density than that of the main body
10 at the time of the magnetic saturation, so that magnetic saturation does not occur in the second core 123a when the magnetic field generated in the inner wall of the seat body portion 3 at the third point in place (P3) is magnetically saturated by the increase of the second voltage (V2), and the third core 123b has a larger magnetic flux density than that of the main body 10 at the time of the magnetic saturation, so that magnetic saturation does not occur in the third core when the magnetic field generated in the inner wall of the seat body portion 3 at the fourth point in place (P4) is magnetically saturated by the increase of the third voltage (V3).
[36] Meanwhile, polarity of the first magnetic saturation magnetic field (MSl) having the magnetic saturation of the third point in place (P3) has the same polarity as that of the second magnetic saturation magnetic field (MS2) having the magnetic saturation of the fourth point in place (P4).
[37] In addition, the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b may be implemented by using a permanent magnet in order to generate magnetic saturation magnetic fields, respectively.
[38] In addition, the opening and closing detector 200 detects change of an induced voltage by change of a magnetic flux which is generated in the magnetic field generator 100, and judges whether the valve disc 20 is closed when the valve disc 20 is mounted in the valve seat 1, or judges whether the valve disc 20 is opened when the valve disc 20 is separated from the valve seat 1.
[39] Operations of the apparatus for detecting opening and closing of the check valve according to the embodiment of the present invention will follow.
[40] As illustrated in FIGS. 4 to 6, one end of the first core 113 is made to contact the first point in place (Pl) on the outer circumferential surface of one side of the seat body portion 3, and the other end of the first core 113 is made to contact the second point in place (P2) on the outer circumferential surface of one side of the seat body portion 3 having a phase opposing that of the first point in place (Pl), that is, a 180-degree phase difference. Accordingly, the first core 113 is made to contact the outer circumferential surface of the seat body portion 3.
[41] The first core 113 is mounted on the outer circumferential surface of the seat body portion 3. The first coil 115 is wound around the outer circumferential surface of the first core 113. The first power supply 111 which supplies the first voltage (Vl) is connected to the first coil 115.
[42] Accordingly, the main magnetic field generator 110 having the first power supply
111, the first core 113 and the first coil 115 on the outer circumferential surface of the seat body portion 3 generates a magnetic field into the inner wall of the seat body portion 3.
[43] As illustrated in FIG. 6, the magnetic field interceptor 120 includes the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b. The first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b have an identical structure, and blocks the magnetic field generated from the main magnetic field generator 110 so that the magnetic field generated from the main magnetic field generator 110 does not flow in the inner wall of the outer circumferential surface of the seat body portion 3. The first magnetic flux interceptor 120a is formed in the seat body portion 3 of the third point in place (P3) of the right-hand side that is clockwise from the first point in place (Pl), and the first magnetic flux interceptor 120b is formed in the seat body portion 3 of the fourth point in place (P4) of the left-hand side that is counterclockwise from the first point in place (Pl). That is, the first magnetic flux interceptor 120a and the second magnetic flux interceptor 120b generate the first and second magnetic saturation magnetic fields (MSl and MS2) having a magnetic saturation state, respectively, in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4). The magnetic field that is generated from the main magnetic field generator 110 does not flow in the inner wall of the outer circumferential surface of the seat body portion 3, by the first and second magnetic saturation magnetic fields (MS 1 and MS2) having a magnetic saturation state, respectively, in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4), but flows into the second point in place (P2), via the valve disc 20 at the first point in place (Pl) which is another path. For example, if polarity of the magnetic field of the first point in place (Pl) is an N-pole, and polarity of the second point in place (P2) is an S-pole, the magnetic field that generated from the main magnetic field generator 110 forms a closed loop of the first point in place (Pl), the valve disc 20 and the second point in place (P2).
[44] As illustrated in FIGS. 4 and 5, the magnetic flux of the magnetic field having a closed loop of the first point in place (Pl), the valve disc 20 and the second point in place (P2) varies at the moment when the valve disc 20 is mounted in the valve seat 1 and the check valve is closed, or at the moment when the valve disc 20 is separated from in the valve seat 1 and the check valve is opened. Therefore, as illustrated in FIG. 7, the opening and closing detector 200 detects change of magnetoresistance of a magnetic circuit according to change of the magnetic flux of the magnetic field and thus detects change of an induced voltage that is induced in the first coil 115. As described above, the opening and closing detector 200 detects change of the induced voltage and correctly judges when the check valve is closed or opened. As a result, the opening and closing detector 200 can accurately detect whether or not the check valve is accurately opened at a time when the check valve should be opened, or whether or not the check valve is accurately closed at a time when the check valve should be closed, to thereby accurately diagnose performance of the check valve.
[45] In addition, the opening and closing detector 200 does not only detect when the check valve is opened or closed as described above, but also detects an induced voltage according to an amount of change of a magnetic flux, since the magnetic flux of the magnetic field generated from the main magnetic field generator 110 is changed according to a position where the valve disc 20 moves, to thus judge to what a degree the valve disc 20 of the check valve is opened, and also accurately judge whether or not the valve disc 20 is correctly mounted in the valve seat 1.
[46] As illustrated in FIG. 6, the first magnetic flux interceptor 120a includes: a second power supply 121a that supplies a second voltage (V2); a second core 123a which contacts the third point in place (P3); and a second coil 125 a which is wound around the outer circumferential surface of the second core 123a and which generates a magnetic field into the inside of the second core 123a by an electric current generated by the second voltage (V2), in which the first magnetic saturation magnetic field (MSl) having a magnetic saturation state is formed in the inner wall of the seat body portion 3 at the third point in place (P3), when the second voltage (V2) is increased. In the case of the first magnetic flux interceptor 120a having the above-described structure, when the second voltage (V2) is slowly increased, an electric current flows in the second coil 125a, and a closed loop magnetic field is formed in the inside of the second core 123a and the inner wall of the seat body portion 3 at the third point in place (P3) contacting the second core 123 a according to the electric current applied to the second coil 125a. As shown in FIG. 9, in the case that the main body 10 of the check valve is formed of cast iron, and that the second core 123a is formed of a silicon steel plate having a larger magnetic flux density (T) than that of the case iron, at the time of magnetic saturation, the inner wall of the seat body portion 3 having the smaller magnetic flux density (T) than that of the second core 123a which is formed of a silicon steel plate is magnetically saturated earlier than the inside of the second core 123a, when the second voltage (V2) is continuously increased, and thus the first magnetic saturation magnetic field (MSl) is formed in the inner wall of the seat body portion 3 of the third point in place (P3).
[47] Magnetic saturation means that a magnetic flux density (T) is saturated without increasing linearly in a magnetic substance, if the magnetic flux density (T) reaches a saturation point (A) on a magnetic saturation curved line even if an electric current is continuously increasingly applied to the second coil 125a as illustrated in FIG. 8. That is, the magnetic flux density (T) also increases lineally according to the electric current flowing in the second coil 125a if the electric current flowing in the second coil 125a increases until a magnetic field intensity reaches a point (B), but the magnetic flux density (T) does not increase any more and is saturated even if the electric current flowing in the second coil 125a is continuously increased if the magnetic field intensity reaches the point (B).
[48] The second magnetic flux interceptor 120b is configured in the same manner as that of the first magnetic flux interceptor 120a. Accordingly, when the third voltage (V3) is increased, the second magnetic saturation magnetic field (MS2) is formed in the inner wall of the seat body portion 3 of the fourth point in place (P4).
[49] Therefore, the magnetic field that has been generated from the main magnetic field generator 110 is blocked by the first and second magnetic saturation magnetic fields (MS 1 and MS2) which have been formed in the inner wall of the seat body portion 3 of the third point in place (P3) and the fourth point in place (P4) by the first and second magnetic flux interceptors 120a and 120b, so that the magnetic field that has been generated from the main magnetic field generator 110 does not flow into the inner wall on the outer circumferential surface of the seat body portion 3.
[50] Polarity of the first magnetic saturation magnetic field (MSl) which has been magnetically saturated at the third point in place (P3) has the same polarity as that of the second magnetic saturation magnetic field (MS2) which has been magnetically saturated at the fourth point in place (P4). Thus, a repulsive force happens each other between the first magnetic saturation magnetic field (MSl) and the second magnetic saturation magnetic field (MS2). As a result, no magnetic field is generated in the inner wall of the outer circumferential surface of the seat body portion 3, except for the inner wall of the third point in place (P3) and the fourth point in place (P4). For example, as illustrated in FIG. 6, if an N-pole is formed in the upper portion of the first magnetic saturation magnetic field (MSl) and an S -pole is formed in the lower portion of the first magnetic saturation magnetic field (MSl), the upper portion of the second magnetic saturation magnetic field (MS2) forms an N-pole and the lower portion thereof forms an S-pole.
[51] Since the first and second magnetic flux interceptors 120a and 120b may be implemented to generate a magnetic saturation magnetic field, respectively, a permanent magnet may be used for the first and second magnetic flux interceptors 120a and 120b, instead of an electromagnet, respectively. Mode for the Invention
[52] As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention. Industrial Applicability
[53] As described above, the present invention can be applied to an apparatus for detecting opening and closing of a check valve in which it is accurately judged whether or not a point in time that the check valve is opened and a point in time that the check valve is closed, and it is accurately judged whether or not a valve disc of the check valve is correctly mounted in a valve seat in order to judge whether or not the check valve has been completely closed, when the check valve are opened and closed, to thereby correctly detect whether or not fluid leaks in the check valve and performance of the check valve is degraded, and to thus judge a correct replacement period of time of the check valve.

Claims

Claims
[1] An apparatus for detecting opening and closing of a check valve, the check valve opening and closing detecting apparatus comprising: a main body which comprises a seat body portion in which a valve seat is formed, and an inlet pipe is connected to one side of the main body, and a valve body portion which is connected to an outlet pipe which is connected to the other side of the main body, to thereby form a flow path along which a flow of fluid that flows in the inlet pipe is derived into the outlet pipe; a valve disc which contacts the valve seat 1 air tightly in the inside of the main body; a transfer portion which makes the valve disc move to thus make the valve disc move to an opened position and a closed position; a magnetic field generator that generates a magnetic field forming a closed loop that begins at a first point in place on the outer circumferential surface at one side of the seat body portion, passes through the valve disc, and arrives at a second point in place on the outer circumferential surface at the other side of the seat body portion; and an opening and closing detector which detects change of a magnetic flux in the magnetic field which has been generated from the magnetic field generator according to a position at which the valve disc moves, to thereby judge whether the check valve is opened or closed, wherein the magnetic field generator comprises: a main magnetic field generator whose one end is connected to the first point in place and other end is connected to the second point in place, to thus generate a magnetic field from the first point in place to the second point in place; and a magnetic field interceptor which blocks the magnetic flux of the magnetic field so that the magnetic flux of the magnetic field generated from the main magnetic field generator is not generated toward the outer circumferential surface of the seat body portion.
[2] The check valve opening and closing detecting apparatus according to claim 1, wherein the main magnetic field generator comprises: a first power supply that supplies a first voltage; a first core whose one end contacts the first point in place, and whose other end contacts the second point in place; and a first coil which is wound around the outer circumferential surface of the first core and which generates a magnetic field into the inside of the first core by the first voltage.
[3] The check valve opening and closing detecting apparatus according to claim 1, wherein the magnetic field interceptor forms magnetic saturation magnetic fields having a magnetic saturation state, respectively in the inner wall of the seat body portion, except for the first point in place and the second point in place.
[4] The check valve opening and closing detecting apparatus according to claim 1 or
3, wherein the magnetic field interceptor comprises: a first magnetic flux interceptor that generates a first magnetic saturation magnetic field having a magnetic saturation state in the inner wall of a third point in place on the outer circumferential surface of the seat body portion, except for the first point in place and the second point in place; and a second magnetic flux interceptor that generates a second magnetic saturation magnetic field having a magnetic saturation state in the inner wall of a fourth point in place on the outer circumferential surface of the seat body portion, in which the fourth point in place has a phase opposing that of the third point in place.
[5] The check valve opening and closing detecting apparatus according to claim 4, wherein the first magnetic field interceptor comprises: a second power supply that supplies a second voltage; a second core whose one end contacts one side of the third point in place, and whose other end contacts the other side of the third point in place; and a second coil which is wound around the outer circumferential surface of the second core and which generates a magnetic field into the inside of the second core by an electric current generated by the second voltage, in which the first magnetic saturation magnetic field having a magnetic saturation state is formed in the inner wall of the seat body portion at the third point in place, when the second voltage is increased, and wherein the second magnetic field interceptor comprises: a third power supply that supplies a third voltage; a third core whose one end contacts one side of the fourth point in place, and whose other end contacts the other side of the fourth point in place; and a third coil which is wound around the outer circumferential surface of the third core and which generates a magnetic field into the inside of the third core by an electric current generated by the third voltage, in which the second magnetic saturation magnetic field having a magnetic saturation state is formed in the inner wall of the seat body portion at the fourth point in place, when the third voltage is increased.
[6] The check valve opening and closing detecting apparatus according to claim 5, wherein the second core has a larger magnetic flux density than that of the main body at the time of the magnetic saturation, so that magnetic saturation does not occur in the second core when the magnetic field generated in the inner wall of the seat body portion at the third point in place is magnetically saturated by the increase of the second voltage, and wherein the third core has a larger magnetic flux density than that of the main body at the time of the magnetic saturation, so that magnetic saturation does not occur in the third core when the magnetic field generated in the inner wall of the seat body portion at the fourth point in place is magnetically saturated by the increase of the third voltage.
[7] The check valve opening and closing detecting apparatus according to claim 5, wherein polarity of the first magnetic saturation magnetic field having the magnetic saturation of the third point in place has the same polarity as that of the second magnetic saturation magnetic field having the magnetic saturation of the fourth point in place.
PCT/KR2008/007136 2007-12-05 2008-12-03 Apparatus for detecting opening and closing of check valve WO2009072804A2 (en)

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Citations (3)

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US5236011A (en) * 1991-06-20 1993-08-17 Martin Marietta Energy Systems, Inc. Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field

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US5008841A (en) * 1989-07-28 1991-04-16 Liberty Technology Center, Inc. Non-invasive system and method for inspection of valves
US5008841B1 (en) * 1989-07-28 1995-09-19 Liberty Technologies Inc Non-invasive system and method for inspection of valves
US5086273A (en) * 1990-04-20 1992-02-04 Liberty Technology Center, Inc. A.C. electromagnetic system for determining position of an encased movable electrically conductive element
US5086273B1 (en) * 1990-04-20 1994-03-08 Liberty Technology Center, Inc.
US5236011A (en) * 1991-06-20 1993-08-17 Martin Marietta Energy Systems, Inc. Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field

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