JP2010107430A - Apparatus for measuring fluid temperature, and protecting tube used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring fluid temperature that can easily perform installation work to support cylinders at site, increases the natural frequencies by a collar, can prevent the occurrence of resonance phenomena, dispenses with strict management of dimensional accuracy in the fitting of a contact piece and the support cylinder, and can easily perform removal work of protecting tubes from the support cylinders, and to provide a protective tube used for the apparatus for measuring temperature. <P>SOLUTION: The apparatus for measuring fluid temperature includes: the support cylinder 2, fixed to a wall of a fluid channel; the protective tube 3, extended toward the side of the fluid channel P through the inside of the support cylinder from an upper end 20; and a thermometer attached into the protecting tube 3 by insertion. The contact piece 31, which abuts against the internal surface 21 of the support cylinder for making the natural frequencies increase, are installed projecting along a circumferential direction at an axial prescribed position near the fluid channel P on the external surface of the protecting tube 3. The contact piece 31 is provided so that all the respective contact portions 21a, which are located along the circumferential direction of the internal surface 21 of the support cylinder by each contact piece 31, are included in a prescribed region R1 of less than 180 degrees. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature measuring device that is inserted into a fluid flow path inside a pipe or the like and measures the temperature of the fluid, and a protective tube used therefor.

  A temperature measuring device that measures the temperature of fluid inside a pipe inserts a hollow-type protective tube called a thermowell into a fluid flow channel from a support tube attached to a mounting hole drilled in the side wall of the pipe. It is a structure formed by incorporating a thermometer (for example, see Patent Documents 1 and 2). The protective tube exposed to the fluid constantly generates vibration due to the Karman vortex on the downstream side, and when the frequency approaches the natural frequency of the protective tube, resonance occurs and the device swings greatly. . As a result, there is a risk of damage caused by interference with the external support tube, or the internal thermometer may be damaged by interference with the inner surface of the protective tube. There is also a risk that the welded part that fixes the support tube to the pipe mounting hole at the base is damaged and the fluid leaks to the outside.

  In order to avoid this resonance phenomenon of the protective tube, the natural frequency of the protective tube is designed to be large in the mounted state, and the ratio between the frequency generated by the Karman vortex and the above natural frequency (the frequency / frequency of the Karman vortex) It is necessary to reduce the natural frequency of the protective tube (approximately less than 0.8). For example, it is effective to shorten the insertion length (protrusion amount) of the protective tube into the fluid flow path, but if the insertion length is short, the temperature measurement is also affected. Therefore, conventionally, as illustrated in FIGS. 6A and 6B, three contact pieces that protrude evenly radially outward at a position corresponding to the base of the support tube 2 on the outer peripheral surface of the protective tube 3. A substantially equilateral triangular collar 4 made of 31,... Is provided and pressed against the inner surface 21 of the support cylinder so that the natural frequency is increased by regarding the length below the collar 4 as an insertion length that vibrates. A mounting structure has been proposed.

  However, the size of the collar 4 is slightly smaller than the inner diameter of the support tube 2 in consideration of inserting the protective tube 3 into the support tube 2 already installed on the pipe wall W in the field. It is necessary to provide a gap for insertion work. However, there is a tolerance in the inner diameter of the support cylinder 2 and the collar 4 of the protective tube 3, and the contact pieces 31 are caused by the gap being too large. Is not in contact with the inner surface 21 of the support cylinder and cannot exhibit the above-described effect of increasing the natural frequency, or cannot be inserted locally because the gap is too small or minus (the size of the collar is larger). It is inevitable that this will occur. That is, it has been very difficult to reliably exhibit the above-described effect due to the contact of the collar 4 while maintaining the ease (possibility) of the work of inserting the protective tube 3.

  There is also a method of fitting the outer diameter of the collar and the inner diameter of the support cylinder and manufacturing them with tolerances. In this case, the collar is manufactured and delivered as a product that is pre-fitted with a protective tube and a support cylinder. It is necessary to weld to the mounting hole of the pipe, and it is not realistic in consideration of an actual use mode in which only the protective tube is replaced while the support cylinder is left as it is. Even if the outer diameter dimension of the collar and the inner diameter of the support cylinder are strictly controlled to secure the contact state of the contact piece, if seizure occurs at the contact part due to use, the protective tube must be replaced for replacement. There is also a problem that it is very difficult to remove from the support tube.

JP-A-10-221178 JP-A-11-258252

  In view of the above situation, the present invention intends to solve the problem that the mounting operation to the support cylinder can be easily performed on site and the natural frequency is increased by the collar (contact piece). It is possible to reliably exhibit the effect of preventing the occurrence of resonance phenomenon, and it is not necessary to manage the dimensional accuracy of the strict fitting between the contact piece and the support cylinder, and it is protected even if the scale is seized. An object of the present invention is to provide a fluid temperature measuring device and a protective tube used therefor, which can easily perform a tube removal operation.

  In order to solve the above-described problems, the present invention provides a support cylinder fixed to a mounting hole drilled in a fluid flow path wall, and extends from the upper end of the support cylinder toward the fluid flow path side through the inside of the support cylinder. And a thermometer inserted into the protective tube. A temperature measuring device for a fluid, wherein the support is provided at a predetermined position in the axial direction near the fluid flow path on the outer surface of the protective tube. A single or a plurality of contact pieces are provided along the circumferential direction to contact the inner surface of the cylinder or the mounting hole to increase the natural frequency, and the circumferential direction of the inner surface of the support cylinder or the mounting hole by each of the contact pieces The fluid temperature measuring device is characterized in that the contact piece is provided so that each contact portion along the line is included in a predetermined region of less than 180 degrees.

  Here, the height dimension (outer diameter of the abutting piece) of the contact piece tip from the axis of the protective tube is set to a value larger than the dimension (inner diameter) from the same axis to the inner surface of the support cylinder or the mounting hole. What has been set is preferred.

  In addition, the position on the outer side of the protective tube is closer to the base end side than the position where the contact piece is provided, and the position in the circumferential direction is opposite to the predetermined area where the contact piece comes into contact. It is also preferable to provide a projecting piece that contacts the inner surface of the support cylinder or the mounting hole at the same position.

  Further, the present invention is a protective tube used in the above-described fluid temperature measuring device, and is in contact with the inner surface of the support cylinder or the mounting hole at a predetermined axial position near the fluid flow path on the outer surface, so that the natural frequency The contact piece for increasing the contact length is formed in a single or a plurality of protrusions along the circumferential direction, and each contact portion along the circumferential direction of the inner surface of the support tube or the mounting hole by each contact piece is less than 180 degrees. There is also provided a protective tube characterized in that the abutment piece is provided so as to be entirely included in a predetermined region.

  Here, what provided the flange part bolted to the upper end part of the said support cylinder in the base end part is a preferable Example.

  According to the fluid temperature measuring apparatus according to the present invention as described above, each contact portion along the circumferential direction of the inner surface of the support cylinder or the inner surface of the mounting hole by each contact piece is all within a predetermined region of less than 180 degrees. Since the contact piece is provided so as to be included, it is possible to shift the axis of the protective tube and the support cylinder in a non-fixed state by maintaining a non-contact region in a range wider than 180 degrees, Even if the outer diameter of each contact piece (height from the protective tube axis at the tip of the contact piece) and the inner diameter of the support cylinder (dimension from the axis of the support cylinder to the inner surface) are substantially the same, protection is provided. When inserting the tube into the support cylinder, a slight gap is formed between the two shafts to create a gap between the tip of the abutting piece and the inner surface of the support cylinder, and the insertion work can be easily performed in this state. It is possible to easily perform the mounting work on site. When the protective tube is fixed, the tip of the abutting piece is in contact with the inner surface of the support cylinder simply by aligning the shaft, so that the natural frequency is increased by the abutting piece to prevent the occurrence of a resonance phenomenon. The effect of performing can be surely exhibited.

  Further, with such a structure, even if the outer diameter of the contact piece on the protective tube side is slightly larger than the inner diameter of the support cylinder, the above-mentioned good condition is obtained even if both axes are slightly shifted in the fixed state. The contact state between the abutment piece and the inner surface of the support cylinder can be made more secure while maintaining proper mounting workability, and the dimensional accuracy of strict fitting between the contact piece and the support cylinder is managed. Manufactured and delivered as a pre-fitted and combined product of a protective tube and a support tube, and there is no need to weld the support tube to the mounting hole of the piping on site, allowing for tolerances in dimensional accuracy ( The contact piece may be set to a larger size), facilitating production management, and sufficiently adapting to an actual usage mode in which only the protective tube is replaced while the support tube remains unchanged. Furthermore, even if the tip of the contact piece and the inner surface of the support cylinder are seized due to use, the contact portion of the contact piece is limited to a predetermined region of less than 180 degrees, so that a slight impact is given or squeezed. It is possible to easily separate them and to remove them easily.

  In addition, the position on the base end side with respect to the position where the contact piece on the outer surface of the protective tube is provided, and the position in the circumferential direction is on the opposite side to the predetermined region where the contact piece contacts. Similarly, since the projecting piece that contacts the inner surface of the support cylinder or the mounting hole is provided, when the protective tube is inserted into the support cylinder, the contact tube and the projecting piece are In both cases, there is a gap between the inner surface of the support cylinder, and the insertion work can be easily performed in this state, and the attachment work to the support cylinder can be easily performed on site, and the protective tube is fixed. By fixing the base end of the protective tube to the mounting hole while holding the side of the projecting piece, the contact piece on the tip side can be securely attached to the inner surface of the support cylinder by the lever principle using the projecting piece as a fulcrum. It becomes possible to fix the protective tube in the contacted state, and the resonance prevention effect by the contact piece is more sure. It can be exhibited to.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1A is a longitudinal sectional view showing the overall configuration of a temperature measuring apparatus according to the present invention, FIGS. 1 and 2 are a first embodiment, FIGS. 3 and 4 are a second embodiment, and FIG. In the drawings, reference numeral 1 denotes a temperature measuring device, 2 denotes a support cylinder, 3 denotes a protective tube, and P denotes a fluid flow path.

  As shown in FIG. 1A, the temperature measuring device 1 includes a support cylinder 2 fixed to a mounting hole 10 formed in a fluid flow path wall W, and an upper end portion 20 of the support cylinder 2 through the inside of the support cylinder. A protective tube 3 extending toward the fluid flow path P and a thermometer (not shown) inserted into the protective tube 3 are provided. At a predetermined position in the axial direction near the fluid flow path P on the outer surface of the protective tube 3, the natural frequency of the protective tube 3 is increased by contacting the inner surface 21 of the support tube 2 (or the inner surface 11 of the mounting hole 10). One or a plurality of contact pieces 31 are provided along the circumferential direction. In particular, the contact piece 31 has a contact portion 21a formed by each contact piece 31 along the circumferential direction on the inner surface 21 of the support cylinder (or the inner surface of the mounting hole) within a range of a predetermined angle (α) of less than 180 degrees. Even if the outer diameter of each abutment piece and the inner diameter of the support cylinder are made substantially the same, the axes of the protective tube and the support cylinder are slightly shifted. The attachment / detachment operation can be easily performed, and the tip of the contact piece can be reliably brought into contact with the inner surface of the support cylinder to prevent the occurrence of a resonance phenomenon.

  The support cylinder 2 is made of a cylindrical member having an inner diameter that is substantially the same as the inner diameter of the mounting hole 10 as in the prior art, and protrudes outwardly from the pipe or the like by welding and fixing the lower end portion 22 to the opening end 10a of the mounting hole 10. It is installed. As in the conventional case, the protective tube 3 also has a base end 32 fixed to the upper end 20 of the support tube 2 and extends downward from the support tube 2 through the thermometer. A hollow portion 30 for mounting is formed, and an attachment portion 30a including a screw groove for attaching a thermometer is formed at an upper end portion of the hollow portion. Note that the outer diameter of the support cylinder 2 may be matched with the inner diameter of the mounting hole 10, and the support cylinder 2 may be inserted into the mounting hole 10.

  The temperature measuring device 1 can of course be combined with the support tube 2 and the protective tube 3 in advance at a factory, and the combined set can be brought to the site and fixed in the mounting hole 10. The support tube 2 is fixed to the mounting tube 10 by welding in advance, and the protective tube 3 is attached to the support tube 2 with bolts or the like. The base end portion 32 of the protective tube 3 and the upper end portion 20 of the support tube 2 are attached to the support tube 2. The flange portions 33 and 23 are respectively provided, and the flange portions 33 and 23 can be detachably fixed by the mounting bolts 6 through the gasket 5. Instead of such a bolting structure, a structure in which a protective tube is screwed and fixed to the upper end portion of the welding stopper or the support tube 2 may be used.

  As in the conventional example shown in FIG. 6, the contact piece 31 is constituted by a collar 4 attached to a predetermined position in the axial direction near the fluid flow path P on the outer surface of the protective tube 3, but in FIG. As shown, the number of the abutment pieces 31 is only one, unlike the conventional example, and the outer diameter of the tip 3a and the inner diameter of the support cylinder 2 are substantially the same and are securely supported in a fixed state. It is comprised so that it may contact | abut to the cylinder 2 inner surface. In this example, the contact portion 21a on the inner surface 21 of the support cylinder with which the contact piece 31 contacts has the same width as the tip portion 3a of the single contact piece 31. Specifically, the angle range (α) is 20. The region R1 is about 30 degrees, and the non-contact region is maintained in the range of 330 to 340 degrees excluding the region R1, so that the protective tube 3 before being fixed is radially displaced in the support cylinder 2. It is possible to move to.

  The collar 4 having the abutting piece 31 may be one in which the outer surface of the protective tube 3 is bulged and deformed, or a collar member separately formed in a ring shape may be externally fitted to the protective tube 3. Further, not the collar 4 but only the contact piece 31 may be provided on the outer surface of the protective tube 3 by welding or the like. In the example of FIG. 1B, the shape of the tip 31a of the abutting piece 31 is a curved surface having substantially the same radius of curvature as the inner surface 21 of the support tube, thereby maintaining the contact angle range of 20 to 30 degrees as described above. However, for example, as shown in FIG. 2 (a), the radius of curvature may be set smaller than the curvature of the inner surface 21 of the support tube so as to be substantially point contact. As a result, the contact portion 21a becomes a small region R1 having an angle range (α) of 10 degrees or less, and is easily peeled off after seizure, and the removal work becomes easier.

  The number of the contact pieces 31 is such that all of the contact portions 21a of the inner surface 21 of the support tube by the contact pieces are all included in the predetermined region R1 within the angle (α) range of less than 180 degrees. Of course, it is possible to provide two or more as shown in FIGS. FIG. 2 (b) is provided with contact pieces 31, 31 at two locations, and the angular range of each contact portion 21a is about 20 to 30 degrees as in FIG. 1 (b). All the contact portions 21a and 21a are also configured to be within an angle α of less than 180 degrees. FIG. 2C shows contact pieces 31, 31, 31 provided at three locations, and the contact portions 21 a, 21 a, 21 a are all configured to fall within an angle α of less than 180 degrees. Yes. FIG. 2 (d) shows four independent contact pieces 31. The contact portions 21a,... By these contact pieces 31, are all within an angle α of less than 180 degrees and are protected. The tube 3 is configured to be movable in the radial direction in the support tube 2. In addition, it is of course possible to provide five or more contact pieces.

  As shown in FIGS. 2A and 2D, it is preferable to reduce the radius of curvature of the contact piece tip 31a to reduce the angle range of the contact portion 21a. The angle range of the contact portion 21a may be increased. For example, it is possible to provide one partial fan-shaped contact piece having a contact portion of less than 180 degrees. If the height of the tip 31a of the contact piece 31 from the axis of the protective tube is set to a value larger than the size from the axis of the support cylinder or the mounting hole to the inner surface, Although there is a possibility that the shaft of the support cylinder is slightly displaced, this is a preferred embodiment in that it can be surely brought into contact.

  Next, a second embodiment will be described based on FIGS.

  In the present embodiment, as shown in FIGS. 3A and 3B, the position closer to the base end side than the position of the contact piece 31 on the outer surface of the protective tube 3, in this example, close to the upper end portion 20 of the support cylinder 2. The projecting piece 7 which is also in contact with the inner surface 21 of the support cylinder is provided at an appropriate position on the opposite side of the axis with respect to the angle region where the contact piece 31 contacts and the shaft, and the protective tube 3 is fixed. At this time, the abutting piece 31 can be fixed in a state of being surely abutted against the inner surface 21 of the support cylinder while pressing the base end portion 32 in the lateral direction where the protruding piece 7 is present. If the projecting piece 7 is in a position close to the abutting piece 31 in the axial direction, there is no gap during insertion, as in the case of the conventional collar, and the operation becomes difficult. 2, the protective tube 3 is slightly tilted so that both the contact piece 31 and the projecting piece 7 have a gap with the inner surface 21 of the support cylinder so that the insertion operation can be performed easily.

  In FIG. 4 (a), when there are two or more contact pieces 31, a similar projecting piece 7 is provided at an approximately central angular position on the opposite side of the predetermined region R1 where the contact pieces 31, 31 come into contact. An example is shown. FIG. 4B shows an example in which, when there are two or more contact pieces 31, the projecting pieces 7 and 7 are provided at angular positions symmetrical to the position of each contact piece 31 and the axis, respectively. Is shown. In the case of this embodiment, it is effective in that the contact piece 31 can be fixed in a fixed contact state by welding while pressing the base end portion 32, particularly in the case of fixing by welding stopper instead of the mounting bolt 6. is there.

  Next, a third embodiment will be described based on FIG.

  In the present embodiment, a bulging portion 8 that fits in close contact with the inner surface of the opening of the upper end portion 20 of the support tube 2 is provided on the proximal end side of the protection tube 3, thereby the protection tube 3 and the support tube 2. These axes can be easily aligned, and the contact piece 31 can be contacted more reliably. In this example, the bulging portion 8 is configured by expanding a part of the outer periphery. For example, the bulging portion 8 is provided with one or a plurality of ring-shaped ridges extending in the circumferential direction or a plurality of ridges extending in the axial direction. A plurality may be provided in the circumferential direction.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. For example, in each of the above embodiments, the contact piece 31 is provided at a predetermined position on the distal end side. However, in addition to this, the contact piece may be provided at a slightly shifted position. However, it is necessary that all of the contact pieces are included in a region within a predetermined angle range in addition to the added contact pieces. Moreover, in the said embodiment, although the support cylinder 2 and the protective tube 3 were comprised separately, you may comprise integrally. In this case, the present invention functions particularly effectively in the case of a structure in which the contact piece contacts the inner surface of the mounting hole 10.

  Next, the result of a vibration test for confirming an increase in the natural frequency due to the protective tube contact piece will be described.

(Test specimen)
The support cylinder and protective tube of the temperature measuring apparatus having the structure shown in FIG. 1 were used. The inner diameter of the support cylinder and the outer diameter of the contact piece are 49.22 mm, the length of the support cylinder is 209.5 mm, the length from the flange surface to the tip of the protective tube is 350 mm, and the tip of the contact piece is also from the flange surface. The dimension to the side end surface is 200.5 mm, and the thickness of the contact piece is 12 mm.

(Test method)
The tapping test method (blow test method) was adopted. In the tapping test, a sensor (accelerometer) that detects vibration is attached to the tip of the protective tube of the specimen, and the tip of the protective tube is struck, and the resulting vibration is detected and amplified by the sensor. The amplified electrical signal was subjected to frequency analysis or damping ratio analysis to obtain vibration characteristics. The test was measured when the protective tube contact piece was in contact with the inner surface of the support cylinder (lightly contacted and strongly contacted) and when it was not contacted by bolt adjustment or the like. The results are shown in FIG. 7 and Table 1 below.

  As shown in the results of FIG. 7 and Table 1, the natural frequency in the case of non-contact is 212.5 to 215 Hz, whereas the natural frequency in the case of contact (strong / light) by the contact piece is It was 522.5-777.5 Hz, and the increase effect of the natural frequency could be confirmed. Thereby, it can be seen that the occurrence of the resonance phenomenon can be prevented. It can also be seen that the damping ratio increases by two orders of magnitude by contact. The damping ratio is related to the resonance magnification when resonance occurs, and the relationship between the resonance magnification Q and the damping ratio ζ is Q = 1 / 2ζ. Therefore, if the damping ratio ζ increases by contacting with the abutting piece as in the present invention, the resonance magnification Q that is inversely proportional to it decreases, and even if resonance occurs in the scale, the vibration becomes small, and due to the vibration. It can be seen that breakage of each part can be avoided. The attenuation ratio is larger when the contact piece is lightly contacted than when the contact piece is strongly contacted. This is because when the contact piece is lightly contacted, the restraining force due to the contact becomes weaker, and although the natural frequency decreases correspondingly, slip and minor collisions are likely to occur at the contact point, and the damping ratio increases accordingly. It is considered a thing.

(A) is a longitudinal cross-sectional view which shows the temperature measuring apparatus which concerns on 1st Embodiment of this invention, (b) is XX sectional drawing. (A)-(d) is sectional drawing which similarly shows the modification of a temperature measuring device. (A) is a longitudinal cross-sectional view which shows the temperature measuring apparatus which concerns on 2nd Embodiment of this invention, (b) is YY sectional drawing. (A), (b) is sectional drawing which similarly shows the modification of a temperature measuring device. The longitudinal section showing the temperature measuring device concerning a 3rd embodiment of the present invention. (A) is a longitudinal cross-sectional view which shows the conventional temperature measuring apparatus, (b) is ZZ sectional drawing. The graph which shows the result of a vibration test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature measuring device 2 Support cylinder 3 Protective tube 4 Collar 5 Gasket 6 Mounting bolt 7 Protruding piece 8 Swelling part 10 Mounting hole 10a Open end 11 Inner surface 20 Upper end part 21 Inner surface 21a Each contact part 22 Lower end part 23 Flange part 30 Hollow Part 30a Mounting part 31 Contact piece 31a Tip part 32 Base part 33 Flange part P Fluid flow path R1 Predetermined area W Flow path wall

Claims (5)

A support cylinder fixed to a mounting hole drilled in the fluid flow path wall;
A protective tube extending from the upper end of the support tube to the fluid flow path side through the inside of the support tube;
A fluid temperature measuring device comprising a thermometer inserted into the protective tube,
Single or a plurality of contact pieces projecting in the circumferential direction are provided at predetermined positions in the axial direction of the outer surface of the protective tube close to the fluid flow path to increase the natural frequency by contacting the inner surface of the support tube or the mounting hole. And
The contact piece is provided so that each contact portion along the circumferential direction of the inner surface of the support cylinder or the mounting hole by each contact piece is included in a predetermined region of less than 180 degrees. Measuring device for fluid temperature.   A fluid temperature measuring device in which a height dimension from the axis of the protective tube at the tip of the contact piece is set to a value larger than a dimension from the axis to the inner surface of the support cylinder or the mounting hole.   A position on the base end side of the outer surface of the protective tube with respect to the position where the contact piece is provided, and a position in the circumferential direction is opposite to the predetermined area where the contact piece comes into contact with the axis. Similarly, a fluid temperature measuring device provided with a projecting piece that contacts the inner surface of the support tube or the mounting hole.   A protective tube used in the fluid temperature measuring device according to any one of claims 1 to 3, wherein the protective tube or the mounting hole is provided at a predetermined position in the axial direction near the fluid flow path on the outer surface. Each abutment portion is formed by projecting a single or a plurality of abutting pieces that abut and increase the natural frequency along the circumferential direction, and each abutting portion along the circumferential direction of the inner surface of the support cylinder or the mounting hole by each abutting piece However, the contact piece is provided so as to be included in a predetermined region of less than 180 degrees.   The protective tube according to claim 4, wherein a flange portion that is bolted to an upper end portion of the support cylinder is provided at a base end portion.

Images