JP2009264757A - Pressure-measuring device of fluid in passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-measuring device of a fluid in passage easily manufactured with a simple structure, which is not accompanied by spilling of the pollution of the pressure-receiving fluid into the passage. <P>SOLUTION: A pressure measuring device measuring the pressure of a pressure fluid flowing in passage includes: a pipe 21, providing the passage where the pressure fluid flows, which has a thin film-shaped receiving part 23, formed by scrapping a part of its outer circumference into an annular shape, varying according to the pressure of the pressure fluid; an outer case holding member 22, closely fitted so as to surround the pressure receiving part of the pipe, having an opening part 25 for measuring; and a load converter 31 inserted into the opening part, having a detecting element 33, which is arranged to be brought into contact with the pressure-receiving part of the pipe and is displaced, according to the variation in the receiving part. The load converter 31 converts the displacement of the detecting element into an electrical signal, indicating the pressure of the pressure fluid that flows in the passage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure measurement device that measures the pressure applied to a pipe wall in a pipe line without contact with the fluid in the pressure measurement of the pressure fluid flowing in the pipe line.

FIG. 1 shows an outline of a conventional measuring method for measuring the pressure of a pressurized fluid flowing in a pipe line.
As shown in the drawing, a metal tube 10 forming a conduit through which a pressure fluid flows is a thin-film inner tube 11 made of a very thin metal to constitute a pressure receiving portion as an inner peripheral surface of the metal tube 10. And an outer tube 12 made of a thick metal provided so as to surround the outer peripheral surface of the inner tube 11. In the figure, the arrow indicates the direction in which the pressure fluid flows. In order to form a slight gap 13 between the inner tube 11 and the outer tube 12, the inner tube 11 and the outer tube 12 are, for example, an electron beam via sealing portions 11a and 11b at both end faces thereof. Joined by welding. In the sealed gap 13 between the inner tube 11 and the outer tube 12, a liquid such as silicon oil is sealed and filled as a pressure receiving fluid 14. The pressure of the pressure fluid flowing in the pipe line is measured by a pressure measuring device 15 such as a pressure gauge or a pressure sensor provided with a pressure receiving portion that can be inserted through the outer tube 12 and come into contact with the pressure receiving fluid 14. In addition, the metal pipe 10 is provided with flanges 10a and 10b on the outer peripheral surfaces of both ends thereof, and the pipe line can be extended as necessary by connecting similar metal pipes through the flanges. .

  As a result, the pressure of the pressure fluid flowing in the pipe line is transmitted to the pressure receiving fluid 14 enclosed in the gap 13 via the pressure receiving portion of the inner pipe 11, and the pressure change of the pressure receiving fluid 14 is changed in the pressure measuring device 15. It is measured by the pressure measuring device 15 through the pressure receiving unit. Therefore, the pressure measuring device 15 can measure the pressure change of the pressure receiving fluid 14, thereby measuring the pressure of the pressure fluid flowing in the pipe line as a result.

  According to the conventional method for measuring the pressure of the pressure fluid flowing through such a metal tube, when a crack occurs in the thin film inner tube due to overpressure or mechanical damage, it is between the inner tube and the outer tube. There is a problem that the pressure-receiving fluid sealed in the sealed gap flows out into the pipe and the pressure fluid flowing in the pipe is likely to be contaminated. In particular, when such a measurement method is used in a food manufacturing process, there is a risk of contaminating food as a pressurized fluid flowing in the pipeline, resulting in the problem of impairing food safety. Further, when such a measurement method is used in a semiconductor manufacturing process, the outflow contamination of the pressure-receiving fluid such as silicon oil into the pipe line causes a fatal defect in the semiconductor film formation. Furthermore, since these contaminations spread throughout the piping, the entire apparatus involved in the manufacturing process is greatly damaged.

  Moreover, in order to seal between the inner tube 11 and the outer tube 12 in order to form a gap, the end surface of the metal tube having a significantly different welding specific heat resistance between the thin inner tube and the thick outer tube. Therefore, a special method or processing such as electron beam welding is required.

  It is an object of the present invention to provide an easy to manufacture and simple structure that does not involve the outflow contamination of a pressure-receiving fluid into a pipe line, which is used to indirectly measure the pressure of a pressure fluid flowing through a metal pipe. An object of the present invention is to provide a pressure measuring device for fluid in a pipe line.

  A pressure measuring device of the present invention for measuring the pressure of a pressure fluid flowing in a pipe is a pipe that provides a pipe through which the pressure fluid flows, and is formed by scraping a part of the outer peripheral surface into an annular shape. A tube having a thin film-shaped pressure receiving portion that varies according to the pressure of the tube, an outer cylinder holding member that is fitted to surround the pressure receiving portion of the tube and has a measurement opening, and a load that is inserted into the opening An electric transducer that is disposed so as to be in contact with the pressure receiving portion of the pipe and that displaces in accordance with fluctuations in the pressure receiving portion, and the displacement of the detection element indicates the pressure of the pressure fluid flowing in the pipe line. A load converter for converting the signal into a signal.

  In the present invention, at least one annular slit can be provided on the outer peripheral surface of the tube on both sides of the pressure receiving portion of the tube.

  According to the present invention, unlike the conventional pressure measuring device as shown in FIG. 1, there is no fluid inclusion such as silicon oil sealed between the inner tube and the outer tube. There is no risk of fluid contamination due to breakage of the pipe, and even if the pressure receiving portion is broken, it is possible to prevent the entire apparatus related to the manufacturing process involving the pressure measuring device from being greatly damaged.

  Further, according to the present invention, there is no fluid inclusion that expands and contracts depending on the temperature, unlike the conventional pressure measuring device, so that a measurement error due to such expansion and contraction does not occur, and the pipe line Thus, it is possible to provide a pressure measuring device that is not easily affected by the temperature of the pressure fluid flowing through the plate and has excellent temperature stability.

  In addition, according to the present invention, when assembling the pressure measuring device, a simple method of welding or fitting can be adopted without requiring a special method or processing such as electron beam welding. A simple and inexpensive pressure measuring device can be provided.

  In addition, according to the present invention, it is possible to provide a pressure measuring device excellent in temperature stability with less measurement error due to expansion and contraction of the tube due to temperature, as compared with a conventional pressure measuring device.

  FIG. 2 shows a basic configuration of the pressure measuring device of the present invention, FIG. 2A shows a pipe 21 made of, for example, a metal that provides a conduit through which pressure fluid flows, and FIG. 2B is fitted to the pipe 21. The outer cylinder holding member 22 holding the small load converter mentioned later is shown.

  As shown in FIG. 2A, a part of the outer peripheral surface of the pipe 21 is scraped into an annular shape to form a thin pressure receiving portion 23 on the pipe 21. Further, a protrusion 24 that follows the variation of the pressure receiving portion 23 is formed near the center of the pressure receiving portion 23 on the outer peripheral surface of the tube 21 in which the pressure receiving portion 23 is formed, for example, by welding or adhesion. As a result, when the tube 21 expands or contracts due to pressurization or decompression of the pressurized fluid flowing in the conduit, the pressure receiving portion 23 fluctuates and the protrusion 24 moves up and down. The vertical movement of the protrusion 24 is detected by a load converter, and the pressure of the pressure fluid flowing in the pipe line is measured. By the protrusion 23 formed on the pressure receiving portion 23, the displacement of the pressure receiving portion 23 can be measured as a displacement force concentrated at one point, thereby ensuring high sensitivity of pressure measurement.

  The outer cylinder holding member 22 shown in FIG. 2B is applied to the entire apparatus related to the manufacturing process in which the pressure measuring device is involved even when the thin film-shaped pressure receiving portion 23 formed in the tube 21 is damaged. It functions as a protective member that prevents a great deal of damage, and can guarantee the continuation of the work process.

  FIG. 3 is a schematic view showing an embodiment of the pressure measuring device of the present invention assembled by fitting the outer cylinder holding member 22 to the tube 21. In order to fit and fix the outer cylinder holding part 22 to the tube 21, a special welding method such as electron beam welding is not necessary, and a general Tig welding or fitting method may be used.

  As shown in FIG. 3, a load converter 31 is inserted into the measurement opening 25 of the outer cylinder holding part 22, and the load converter 31 is attached to the outer cylinder holding member 22 by a fastening member 32 such as a screw. It is attached to be adjustable.

  The load converter 31 includes, for example, a small metal diaphragm (not shown), a detection element 33 such as a steel ball that contacts the protrusion 24 formed on the pressure receiving portion 23 of the tube 21, and a semiconductor strain gauge. And a semiconductor pressure sensor chip (not shown) including a Wheatstone bridge circuit. The sensing element 33 is displaced in response to the vertical movement of the protrusion 24 due to the fluctuation of the pressure receiving portion 23, and the displacement is transmitted to the diaphragm, thereby deforming the metal diaphragm. This deformation of the diaphragm is converted into an electrical signal by the semiconductor pressure sensor chip, that is, by capturing a slight pressure distortion of the diaphragm with a resistance change. The converted electric signal is used as a measurement value indicating the pressure of the pressure fluid flowing in the pipe line. The contact state between the detection element 33 of the load transducer 31 and the protrusion 24 of the pressure receiving portion 23 affects the sensitivity of the load transducer 31 and can be adjusted by the fastening member 32 so that no offset occurs. is there. The tightening member 32 can be further finely adjusted in the contact state by providing a fine adjustment screw. In the load converter 31, instead of the steel ball detection element, a rod-like protrusion called a pivot or cantilever is used so that it abuts on the protrusion 24 formed on the pressure receiving part 23 of the tube 21. Also good.

  In addition, the pipe | tube 21 can extend a pipe line as needed by providing the flanges 21a and 21b by the welding on the outer peripheral surface of the both ends, for example, and connecting the same pipe | tube via this flange. .

  FIG. 4 is a schematic view showing a second embodiment of the pressure measuring device of the present invention assembled by fitting the outer cylinder holding member 22 to the pipe 21, and in particular, the pressure fluid flowing in the pipe line Is advantageous when is a hot fluid.

  When the pressure fluid is hot, expansion and contraction due to temperature occurs in the tube 21 in the direction indicated by the arrow 40, causing the load converter 31 to generate an error as a drift. In order to solve this problem, as shown in the figure, annular slits 41 are formed on the outer peripheral surface of the tube 21 on both sides of the pressure receiving portion 23 of the tube 21. The position and number of the slits 41 can be appropriately determined according to the material or strength of the tube 21, the characteristics of the pressure fluid flowing through the conduit, the temperature, and the like. In order to avoid the bias of the heat conduction characteristics with respect to the load converter 31, as described above, the slits 41 are preferably provided on both sides of the pressure receiving portion 23 of the pipe 21 and symmetrically. By providing such a slit 41, the expansion and contraction due to the temperature of the tube 21 is released, and the influence of the distortion caused by the expansion and contraction on the load converter 31 is reduced.

FIG. 1 shows an outline of a conventional measuring method for measuring the pressure of a pressurized fluid flowing in a pipe line. FIG. 2 shows a basic configuration of the pressure measuring device of the present invention, FIG. 2A shows a tube forming a conduit through which a pressure fluid flows, and FIG. 2B is fitted to the tube of FIG. The outer cylinder holding member holding a load converter is shown. FIG. 3 is a schematic view showing a first embodiment of the pressure measuring device of the present invention. FIG. 4 is a schematic view showing a second embodiment of the pressure measuring device of the present invention.

Explanation of symbols

21: Tube 21a, 21b: Flange 22: Outer cylinder holding member 23: Pressure receiving portion 24: Protruding portion 25: Opening portion 31: Load transducer 32: Tightening member 33: Detection element 41: Slit

Claims (4)

In the pressure measuring device that measures the pressure of the pressure fluid flowing in the pipeline,
A pipe (21) for providing a pipe line through which the pressure fluid flows, and is formed by scraping a part of the outer peripheral surface into an annular shape, and has a thin-film pressure receiving part (23) that varies according to the pressure of the pressure fluid. A tube (21);
An outer cylinder holding member (22) fitted so as to surround the pressure receiving portion (23) of the tube (21) and having a measurement opening (25);
A load transducer (31) inserted into the opening (25), which is disposed so as to come into contact with the pressure receiving portion (23) of the pipe (21) and is displaced in accordance with a change in the pressure receiving portion (23). And a load converter (31) for converting the displacement of the sensing element (33) into an electric signal indicating the pressure of the pressure fluid flowing in the pipe. .   The detection element (33) is any one of a steel ball, a pipette, or a cantilever disposed so as to abut on a protrusion (24) formed on the pressure receiving portion (23) of the pipe (21). The pressure measuring device according to claim 1.   The load converter (31) is attached to the pressure receiving part (23) of the pipe (21) in an adjustable manner in the measurement opening (25) of the outer cylinder holding member (22). 3. The pressure measuring device according to 1 or 2.   The at least 1 annular slit (41) is formed in the outer peripheral surface of a pipe | tube (21) on both sides of the pressure receiving part (23) of a pipe | tube (21), The one of Claim 1 thru | or 3 characterized by the above-mentioned. Pressure measuring device.

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