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
  • F16K37/0025—Electrical or magnetic means
  • F16K37/0041—Electrical or magnetic means for measuring valve parameters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
  • G01S15/06—Systems determining the position data of a target
  • G01S15/08—Systems for measuring distance only
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/88—Sonar systems specially adapted for specific applications

Definitions

• the present invention relates generally to the field of testing the condition of valves, and, most specifically to testing of check valves.
• a check valve is a type of one-way valve used in the control of fluid flow through conduits.
• the check valve permits the flow of fluid i ' n a first direction through a conduit and prevents fluid flow in the reverse direction.
• a check valve is generally constructed with a disk which is mounted to a pivoting hinge. When fluid is flowing in the allowed direction, the fluid forces the disk to pivot upward to allow passage. When there is no fluid flow or when fluid attempts to flow in the reverse direction, the disk pivots (usually gravity drop) down to seal the conduit and prevent reverse flow.
• all of the parts of the check valve are located inside the valve chamber with no external parts available for visual inspection.
• the present invention teaches a method and apparatus for testing the condition of a check valve while the valve is fully assembled and operating under various flow conditions, including no-flow.
• the present invention comprises the use of an ultrasonic sound transducer to send high frequency sound waves through the check valve casting and through the transported fluid to the valve disk. Reflection of the sound waves is detected and analyzed through the use of signal recording and conditioning devices to assist in determination of the positioning and movement of the valve disk.
• Still another object of the present invention is to provide a check valve testing method and apparatus for determining if a check valve is still operable yet being subjected to damaging operating conditions.
• Fig. 1 is a schematic representation of the check valve testing system, in accordance with the present invention.
• Fig. 2 is a cut-a-way, side view of a check valve tested by the invention of Fig. 1, and depicting a portion of the check valve testing system of Fig. 1.
• Fig. 3 is a schematic representation of a portion of the check valve testing system of Fig. 1, showing an alternate embodiment.
• Fig. 4 is a representative view depicting various, alternate points of placement of the transducers of the check valve testing system of Fig. 1.
• the sending unit 12 is connected by signal cable 21 to a first recording device 23, such as an oscilloscope, and is also connected by the signal cable 21a to a signal conditioning device 25.
• the wave receiving unit 16 is connected by signal cable 28 to the first recording device 23 and by cable 28a to the signal conditioning device 25.
• the signal conditioning device 25 comprises a discriminator 26 and a counter/delay device 27, the functions of which are described below.
• the signal conditioning device 25 is connected by signal cable 30 to the first recording device and by a signal cable 31 to a second recording device 33, such as a second oscilloscope.
• the signal cable 31 is connected to an analog output terminal 34 of the signal conditioner 25.
• the transducers 13, 18 are seen as acting upon a check valve assembly 40, which assembly is seen in detail in Fig. 2.
• the check valve assembly 40 comprises a fluid conduit 41 providing for normal
• valve chamber 45 which houses a swinging disk assembly 46.
• the swinging disk assembly 46 comprises a valve disk 48 mounted to a hinge arm 49, which hinge arm is pivotally connected at a pin 50 which is mounted to the inner wall 51 of the valve chamber.
• the valve disk 48 and hinge arm 49 are forged as one component.
• the valve disk 48 is bolted to the hinge arm 49 by a stud nut 53 bolted to a threaded stud 54 protruding upward from the disk 48.
• the check valve assembly 40 further includes a lower valve stop 56 and a back stop 57.
• the check valve testing system 10 of the present invention is set-up, in the field, at the location of the check valve along the fluid conduit system.
• the wave sending unit 12 is set to generate and deliver a pulsing, ultrasonic signal. That is, a sound wave signal is generated repeatedly at desired, equal intervals. The interval of time between each pulse shall be termed the "pulse interval”. The rate at which the pulses occur shall be termed the "pulse rate”.
• the frequency of the ultrasonic wave is set sufficently high to assure transmission of the sound wave through the different medium of the valve casting, fluids, and any other materials associated with the valve assembly 40.
• the user places the sending transducer 13 and receiving transducer 18 at the valve assembly body so as to direct the /
• tw transducers 13, 18 are placed relative to one another such that th receiving transducer 18 can receive the sound wave from the sendin transducer 13 after the waves have been directed into the valv chamber 45.
• Some examples of alternate transducer 13, 18 placemen are shown in Figs. 3 and 4. Note that the transducer location depicted in Fig. 3 and as positions “a", “b” and “c” of Fig. 4 ar
• the wave sending unit 1 generates a trigger signal upon the generation of each ultrasoni pulse at the sending transducer 13.
• This trigger signal is delivere along signal cable 21 to the first recording device 23. At the firs recording device, this trigger signal triggers the recording devic to begin its recording sequence. For example, in the.
• the trigger signal triggers the oscilloscope to begin its sweeping function.
• This same trigger signal is delivered along signal cable 21a to the signal contitioner 25 where it triggers the signal conditioner to the fact that a sound wave has been delivered by the transducer 13 and the conditioner 25 should begin its condi ⁇ tioning functions as discussed below.
• the wave receiving trans ⁇ ducer 18 begins to receive reflected and refracted sound waves from various components of the valve assembly 40. For example, a portion of each wave generated at the sending transducer 13 is reflected or refracted by the metal casting of the valve assembly 40, a portion of the wave is reflected and refracted by the fluid within the valve chamber 45 and a portion of the wave is reflected by the valve disk 48. Various other materials and components within the valve assembly 40 and valve chamber 45 may also reflect and refract portions of each wave generated by the sending transducer 13. Thus, for each wave (each pulse) generated at the sending transducer 13, a plurality of waves are received by the receiving transducer 18.
• the waves received by the receiving transducer 18 shall be referred to in this disclosure as "reflected waves".
• the wave receiving unit 16 acknowledges receipt of the wave and generates a signal which is sent along signal cable 28 to the first recording device 23.
• the signal is recorded by the recording device 23.
• each signal corresponding to a received each signal corresponding to a received,
• reflected wave is recorded in the form of a spike. Since the reflected waves are received at the receiving unit 18 at different times, a- series of signals, separated in time, are sent by the receiving unit 16 to the oscilloscope 23. Thus, the series of signals appear as a plurality of spikes spaced across the screen of the oscilloscope. The Amplitude of the spikes corresponds to the energy of the respective, reflected wave received at the receiving trans ⁇ ducer 18. An example of such a sweep is given by trace "f" of Fig. 1. The pulse rate of the sending unit 12 is adjusted by the user to assist in receiving a good sweep trace at the oscilloscope 23.
• the pulse rate is set so that a substantial number of the reflected waves from the first generated sound wave are received at the receiving unit 18 before the second generated wave is sent at the sending transducer 13.
• a trigger signal is sent from the sending unit along signal cable 21 to the oscilloscope triggering the oscilloscope to begin a new sweep.
• the oscilloscope records input from the receiving unit 16 corresponding to the received, reflected waves relating to the respective generated sound wave pulse.
• the signal conditioner 25 performs two main functions: (1) isolating of the target spike 51 during each single sweep of the first recording device 23; and (2) converting the digital signal associated with each sweep of the first recording device 23 to an analog signal which signal is delivered to the second recording device 33 along signal cable 31.
• the isolating function is accomplished as follows: each time the sending unit 12 generates a pulse, the trigger signal is delivered along cable 21a to the counter/delay device 27 of the signal conditioner 25. This trigger signal resets the counter of the counter/delay device 27 to "zero" to begin counting the relative time since the respective pulse was sent by the sending unit 12.
• the delay mechanism of the counter/delay device 27 further affects the counter by delaying the counter's beginning time by an increment of time selected by the user. In this way, the user adjusts the delay such that the counter does not begin counting until a substantial portion, if not all, of the reflected waves which resulted in the "noise" 60 have been received by the receiving unit 18.
• the signal conditioner 25 also comprises a discriminating device 26. The function of the discriminating device 26is to command the signal conditioner 25 to recognize only signals from the receiving unit 16 which have amplitudes in excess of a selected minimum amplitude. Thus, in practice, the user adjusts the discriminator device 26 such that the signal conditioner 25 discriminates in favor of certain, high amplitude signals.
• the user is able to effectively isolate the target spike 61 from all of the noise spikes 60.
• the signal conditioner discriminated seeks signals during each pulse interval which signals are generated after the delay interval and which signals exceed or equal the minimum discriminating amplitude. Such isolated signals are conveyed by signal cabTe 30 to the first recording device 23 where they are recorded. When an oscilloscope is used, the isolated signal is displayed on the lower trace "g" during each sweep of the oscillo- scope-.
• the counter of the counter/delay device 27 begins counting upon expiration of the delay interval, and continues counting until * the signal conditioner 25 receives a signal from the receiving unit 16 which signal exceeds or equals the discriminating amplitude (i.e. the target spike). Once the counter has stopped counting, the digital output from this
• digital counter is input to a digital-to-analog converter within the signal conditioner 25.
• the output of this D/A converter is delivered through the analog output terminal 34 to the second recording device 33.
• the D/A converter output is, preferrably, in the form of an equivalent voltage such that a low count on the counter results in a low voltage and a high count on the counter results in a high voltage.
• the counter is reset by the trigger signal from the wave sending unit
• the counter beg.ins a new count for each new generated wave and a separate analog signal is generated for each pulse interval. It can be seen that the counter is counting a relative time span over which the soundwave of a given pulse travels from the sending transducer 13 to the valve disk 48 and then to the receiving transducer 18 (the "critical distance"). If it took a long time for the wave to travel this critical distance, then the count of the digital counter will be high and the analog output voltage will be high. Conversely, if it took a relatively short time for the wave to travel the critical distance, then the count of the digital counter will be low and the analog output voltage will be low.
• the output voltage relates in a relative manner to the position of the valve disk 48 within the valve chamber 45.
• the analog output voltage is sent along cable 31 to the second recording device 33 where the voltages corresponding to each of the pulse intervals of the sending unit 12 are collected and recorded.
• the second recording device 33 performs one or more of the functions of collecting, storing, correlating, recording and
• the second recording device 33 is a storage oscilloscope in which the voltages corresponding to the successive pulse intervals of the sending unit 12 are converted to a digital number and stored.
• the storage oscilloscope 33 also functions to successively plot the
• each trace depicts real time. This parameter is called “real time” because it is not reset with each pulse interval of the sending unit 12, but is continuous time spanning the accumulation 5 of a plurality of pulse intervals.
• the recording device is a computer or a combination of oscilloscope and computer in which the computer performs various operations on the analog output of the signal conditioner 25.
• the computer performs spectrum 0 (frequency) analysis of the voltage/time traces.
• the computer uses known mathematical formulas and additional input such as the known velocities of sound through the various materials, calculates the position of the valve disk 48 within the valve chamber 45 at any given point in "real time”.
• the second recording device 33 is an instrumentation analog tape recorder which collects, records and stores the analog signals. The stored data from this tape recorder are subsequently conveyed to an oscilloscope for display and analysis or to a computer for detailed analysis.
• Trace “h” is a representative trace depicting position, and movement of position of the valve disk 48 under fluid flow conditions. It can be seen that, over a period of real time, the voltage, which relates to relative time and to distance of the disk 48 from the transducers 13, 18, fluctuates from higher to lower voltages. This indicates that, at each pulse of the sound wave,
• the trace “h” is indicative of a vibrating or "bouncing" valve disk- 8. This condition is indicative of a poorly sized valve, or some other detrimental condition which will result, in the long term, in failure of the valves.
• Analysis of the output of the first recording device 23 aids in immediate determination of: whether or not the valve disk 48 is actually in place (i.e. broken off or still in place); the relative position of the valve disk 48; and the ability of the swinging disk assembly 46 to fully swing from its open to its closed position.
• a user using the system of the present invention, can test the valve condition under various flow conditions. For example, a first test of the check valve assembly 40 is conducted with full fluid flow through the conduit 41. Analysis of the recordings taken during this first test is used to determine if the valve is (or seems to be) open and if the valve disk is subjected to vibrating or bouncing during the full flow condition. Next, the test is run with the fluid flow set at various flow rates less than the full flow rate.
• the user can record and analyze the position of the valve disk 48 during various flow rates and can record and analyze the effect of lesser flow rate on the vibrating or bouncing of the valve disk 48.
• the user can stop fluid flow through the respective fluid conduit 41 and, during this test, locate the position of the valve disk 48 and record and analyze the swing characteristics of the swinging disk assembly 46 (i.e. Does it bind?).
• the transducers 12, 13 are positioned at the locations indicated as "d" in Fig. 4. With the transducers 13, 18 in this location the user seeks to identify whether or not the valve disk 48 has achieved its fully closed position. Thus, if the valve disk 48 is not fully closed, the sound wave generated at sending transducer 13d will be received (in large portions) at the receiving transducer 18d. However, if the valve disk 48 is fully seated, the valve disk 48 will interfere with the sound wave generated at the sending transducer 13d; and none of the wave, or only a small portion of the wave will be received at the receiving transducer 18d.

Landscapes

• Engineering & Computer Science (AREA)
• Remote Sensing (AREA)
• Radar, Positioning & Navigation (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• Acoustics & Sound (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
• Check Valves (AREA)
• Indication Of The Valve Opening Or Closing Status (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=25450808

Family Applications (1)

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Citations (3)

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• 1987
  • 1987-10-09 WO PCT/US1987/002660 patent/WO1988003241A1/fr not_active Ceased
  • 1987-10-09 EP EP19870907200 patent/EP0288521A4/en not_active Withdrawn
  • 1987-10-09 JP JP62506608A patent/JPH07109254B2/ja not_active Expired - Lifetime
  • 1987-10-28 CA CA000550493A patent/CA1321261C/fr not_active Expired - Fee Related
  • 1987-10-28 ES ES8703083A patent/ES2005421A6/es not_active Expired

Patent Citations (3)

Non-Patent Citations (1)

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