JP6389088B2 - Vibration sensor with thermocouple - Google Patents

Description

  The present application relates to a vibration sensor with a thermocouple, in which a thermocouple for detecting temperature is attached to a vibration sensor for detecting vibration of a measurement object.

  As a conventional vibration sensor with a thermocouple, there is a sensor in which the tip of a detection needle connected to a diaphragm is protruded beyond the end of a casing (see, for example, Patent Document 1). In the above sensor, an annular temperature sensor having a hole through which the detection needle passes is disposed at the tip of the casing, and the detection needle is pressed against the measurement object, so that both the temperature sensor and the vibration needle are measured. The temperature and vibration can be measured simultaneously.

  However, in the conventional vibration sensor with a thermocouple, since a hole for projecting the detection needle is opened in the temperature sensor, a part of the thermocouple including the temperature measuring contact is exposed to the outside, and the thermocouple wire There is a risk that the welded part will corrode and break.

Japanese Utility Model Publication No. 3-93743

  The present application has been made in view of such circumstances, and an object thereof is to provide a vibration sensor with a thermocouple that can prevent corrosion of a thermocouple wire.

  In order to solve the above problems, a vibration sensor with a thermocouple disclosed below includes a cylindrical protective tube, a thin metal plate that covers the opening of the protective tube, a detection needle accommodated in the protective tube, A thermocouple-equipped vibration sensor comprising a thermocouple including a thermocouple wire connected to a thin metal plate, and when measuring the temperature and vibration of the measurement object, the outside of the thin metal plate is in contact with the measurement object At the same time, the inside of the thin metal plate contacts the tip of the detection needle.

  According to the vibration sensor with a thermocouple disclosed below, corrosion of the thermocouple wire can be suppressed.

It is sectional drawing of the vibration sensor with a thermocouple which concerns on 1st Embodiment. It is sectional drawing of the vibration sensor with a thermocouple which concerns on 2nd Embodiment. It is sectional drawing of the vibration sensor with a thermocouple which concerns on 3rd Embodiment.

[First Embodiment]
Hereinafter, the vibration sensor with a thermocouple according to the first embodiment of the present application will be described with reference to FIG. A vibration transmission plate 2 formed with a female screw is screwed to the detection needle 1 formed with a small-diameter male screw at the lower portion, and the upper surface of the vibration transmission plate 2 is in contact with the lower surface of the large-diameter portion of the detection needle 1. An upper electrode plate 3, a piezoelectric element 4, a lower electrode plate 5, and a weight 6 are sequentially inserted below the vibration transmission plate 2, and are brought into contact with each other with a nut 7 and fixed to the detection needle 1. For example, the detection needle 1 and the vibration transmission plate 2 are made of stainless steel, the upper and lower electrode plates 3 and 5 are made of phosphor bronze, and the weight 6 is made of zirconia ceramic. A vibration detection unit of a vibration sensor is formed from the detection needle 1, the vibration transmission plate 2, the upper electrode plate 3, the piezoelectric element 4, the electrode plate 5, and the weight 6.

  The vibration detection unit includes an upper wall 9a in which the upper surface of the vibration transmission plate 2 and the lower surface of the weight 6 are provided with a cut to avoid the detection needle 1 on the side facing away from the front side, and further on the near side from the end on the opposite side of the upper wall 9a. The upper surface of the vibration transmitting plate 2 is placed on the top of the switch fitting 9 by being sandwiched and held by the switch fitting 9 consisting of the bifurcated spring portion 9b extending to the upper side and being biased upward by the spring portion 9b of the switch fitting 9. It is in contact with the lower surface of the wall 9a. The switch fitting 9 has two side walls 9c on both sides extending downward from the upper wall 9a. The side wall 9c and the upper wall 9a are held by the inner wall of the casing 10, whereby the vibration detection unit is Attached to the casing 10. The casing 10 is formed from two casing members on the opposite side and the near side, and is connected by taper screws 11 and 12. For example, the switch fitting 9 is made of stainless steel, and the casing 10 is made of polyetheretherketone resin (PEEK). Lead wires (not shown) from the upper and lower electrode plates 3 and 5 are connected to terminals 14 and 15 of the signal processing circuit 13.

  A detection needle holding member 19 for holding the detection needle 1 is disposed on the outer periphery of the detection needle 1. The detection needle holding member 19 includes an upper tip portion 19a, a lower large diameter portion, and a long hollow portion in the middle. Thus, two windows 20a and 20b are formed on both sides in the hollow portion. A cylindrical protective tube 24 having an inner diameter slightly larger than the outer diameter of the distal end portion 19a is inserted on the outer side of the detection needle holding member 19. The protective tube 24 is fitted into a protrusion 25 indicated by a broken line formed at the lower end of the detection needle holding member 19 to prevent the protection tube 24 from being pulled out. The protective tube 24 is made of stainless steel, the detection needle holding member 19 is made of PEEK, and the ring 22 is made of bakelite.

  A chromel thin plate 17 (thin metal plate) having a substantially reverse concave shape (hereinafter simply referred to as “reverse concave shape”) has an inner diameter slightly larger than the outer diameter of the protective tube 24 and protrudes from the opening of the protective tube 24. The detection needle 1 is joined to the upper surface of the opening of the protective tube 24 with the tip of the detection needle 1 in contact with the inner surface. The tip of the side surface portion 17b of the reverse concave chromel thin plate 17 and the outer periphery of the protective tube 24 are joined together by, for example, a seal portion 21 by glass hermetic treatment.

  A donut-shaped alumel disk 18 (metal disk) having a hole through which the tip of the detection needle 1 protrudes is joined to the central part of the inner surface of the reverse concave chromel thin plate 17 by welding. The outer diameter of the donut-shaped alumel disk 18 can be formed slightly smaller than the inner diameter of the protective tube 24, for example. The chromel wire 16a is joined to the side surface 17b of the chromel thin plate 17 by welding, and the alumel wire 16b is joined to a part of the lower surface of the alumel disc 18 by welding. A thermocouple is formed including the chromel thin plate 17, the alumel disc 18, the chromel wire 16a, and the alumel wire 16b.

  The chromel wire 16a and the alumel wire 16b extend downward along the inner peripheral surface of the protective tube 24, and the chromel wire 16a and the alumel wire 16b are respectively formed between the gap between the detection needle holding member 19 and the casing 10 and between the casings 10. And is connected to the terminals 26 and 27 of the signal processing circuit 13. The chromel wire 16a and the alumel wire 16b are insulated from the welded portion with the chromel thin plate 17 or the alumel disc 18 to the terminals 26 and 27, respectively.

  The chromel thin plate 17 has, for example, a groove-shaped buffer portion 17 a having an inner diameter slightly larger than the outer diameter of the donut-shaped alumel disk 18 and an outer diameter slightly smaller than the inner diameter of the protective tube 24. Is formed. The chromel thin plate 17 is flexible and employs a diaphragm structure having a movable surface 17c that can be displaced up and down from the buffer portion 17a.

  A temperature measuring unit of the temperature sensor is formed from the thermocouple including the chromel thin plate 17, the alumel disc 18, the chromel wire 16a and the alumel wire 16b, the detection needle holding member 19, the ring 22, and the protective tube 24. Yes. A temperature measuring unit is passed through the detection needle 1 and inserted from the upper end opening of the casing 10. The upper and lower slits are provided around the screw holes of the casing 10 corresponding to the taper screws 11 and 12, and the temperature measuring unit is fixed to the casing 10 by screwing the taper screws 11 and 12. The taper screws 11 and 12 constitute biasing means, and the temperature measuring unit can be pulled out of the casing 10 by loosening the taper screws 11 and 12.

  Next, the operation of the vibration sensor with a thermocouple of this embodiment will be described. When the chromel thin plate 17 which is the tip of the temperature measuring unit is pressed against the surface of the steam trap as a measurement object, the chromel thin plate 17 opposes the elastic force of the spring portion 9b of the switch fitting 9 to bring the detection needle 1 inside. Energize to. At this time, mechanical vibration of the steam trap is transmitted to the vibration transmission plate 2 through the detection needle 1, and the pressure fluctuation acts on the piezoelectric element 4. In response to this, voltage fluctuations occur in the piezoelectric element 4. This voltage fluctuation is sent from the electrode plates 3 and 5 to the terminals 14 and 15 of the signal processing circuit 13 via conductors (not shown), amplified and detected by the signal processing circuit 13, and converted to an average value or a peak value. It is calculated and displayed on a display unit (not shown). On the other hand, the surface temperature of the steam trap is detected by the signal processing circuit 13 due to the potential difference between the thermocouple wires 16a and 16b via the chromel thin plate 17 and the alumel disc 18, and amplified to a display unit (not shown). Is displayed.

  According to the first embodiment of the present application, the chromel thin plate 17 pressed against the object to be measured is not provided with a central hole into which the tip of the detection needle 1 enters as in the prior art, and the protective tube 24 is provided. And the thin sheet 17 made of chromel are sealed by glass hermetic treatment, and there is no gap between the upper part of the protective tube 24 and the thin sheet 17 made of chromel. There is no possibility that steam or the like existing around the object enters the protective tube 24. Moreover, since the chromel thin plate 17 is excellent in rust resistance, there is no possibility that the welded portion of the thermocouple wire (chromel wire 16a, alumel wire 16b) is corroded by steam or the like.

  For example, the thickness of the chromel thin plate 17 is preferably 0.05 mm to 3.2 mm, and more preferably 0.1 mm or less. Since the chromel thin plate 17 is extremely thin and flexible as described above, the temperature and vibration of the measurement object can be controlled even if the tip of the detection needle 1 is not directly pressed against the measurement target and passes through the chromel thin plate 17. It can be measured accurately.

[Second Embodiment]
Hereinafter, a vibration sensor with a thermocouple according to a second embodiment of the present application will be described with reference to FIG. In the second embodiment, the height of the side surface portion 37b of the reverse concave chromel thin plate 37 is made slightly higher than the side surface portion 17b of the chromel thin plate 17 of the first embodiment, and the chromel thin plate 37 is placed in the protective tube 24. And are joined by a screw connection 38. The tip of the side surface portion of the chromel thin plate 37 and the side surface of the protective tube 24 can be joined by the seal portion 21 by glass hermetic treatment or the like, as in the first embodiment. In FIG. 2, reference numeral 37 a denotes a buffer portion of the chromel thin plate 37.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

[Third Embodiment]
Hereinafter, a vibration sensor with a thermocouple according to a third embodiment of the present application will be described with reference to FIG. In the third embodiment, instead of the reverse concave chromel thin plate 17 shown in the first embodiment, a circular flat chromel thin plate 47 is used, and this circular flat chromel thin plate 47 and the protective tube 24 are used. Is sealed with a glass ring 30. That is, the lower surface of the chromel thin plate 47 and the upper surface of the glass ring 30 are joined together by a seal portion (not shown) by glass hermetic treatment or the like, and the lower end of the glass ring 30 and the peripheral surface (inner periphery) of the protective tube 24 Surface, outer peripheral surface) are joined by a seal portion 23 by glass hermetic treatment or the like. In FIG. 3, reference numeral 47a denotes a buffer portion of the chromel thin plate 47.

  In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.

[Another embodiment]
In the above embodiment, the alumel wire 16b is welded to the alumel 18 disc, but is not limited thereto, and may be directly welded to the chromel thin plate 17. In this case, it is not necessary to use an alumel 18 disc.

  The bottom surface of the reverse concave chromel plate (17, 37) or the circular flat plate chromel plate 47 is formed in a flat shape, but curved outward in a dome shape starting from the buffer portion (17a, 37a, 47a). It can also be made. In this case, when the tip of the temperature measuring unit is pressed against the steam trap, the outwardly curved chromel thin plates (17, 37, 47) bend inward to increase the amount of bias of the detection needle 1 more. be able to.

  In the present application, the thin plate metal constituting the thermocouple is not limited to the chromel thin plate, and the type of the thermocouple is not limited to the chromel-alumel thermocouple (K type).

  The glass hermetic treatment may be either a compression seal (compression seal) method or a matching seal (match seal) method, and the method of forming the seal portions (21, 23) is also limited to the glass hermetic treatment. is not. For example, the seal portion may be formed by welding.

  The present application can be used for a vibration sensor with a thermocouple that can detect the vibration of the measurement object and also can detect the temperature of the measurement object.

1 detection needle 16a chromel wire 16b alumel wire 17 chromel thin plate 18 alumel disc 24 protective tube

Claims (4)

Thermocouple-equipped vibration comprising a cylindrical protective tube, a thin metal plate covering the opening of the protective tube, a detection needle housed in the protective tube, and a thermocouple including a thermocouple wire connected to the thin metal plate A sensor,
A thermocouple-equipped vibration sensor in which, when measuring the temperature and vibration of an object to be measured, the outside of the sheet metal is in contact with the object to be measured, and the inside of the sheet metal is in contact with the tip of the detection needle.   The vibration sensor with a thermocouple according to claim 1, wherein the thin metal plate is made of chromel.   The vibration sensor with a thermocouple according to claim 1 or 2, wherein the vibration sensor with a thermocouple has a metal disk having a hole from which a tip of the detection needle protrudes on an inner surface of the thin metal plate. The vibration sensor with a thermocouple according to claim 3, wherein the metal disk is made of alumel.

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