JP2011133343A - Pressure measuring apparatus and combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent residual pressure anomalies due to the intrusion of air into a leakage preventing member. <P>SOLUTION: A pressure measuring apparatus includes a pressure measuring device provided with a connection member 6 having a liquid inlet, an oil supply pipe 3, a tubular joint 7 having an upper end connected to the connection member 6 and a lower end connected to the oil supply pipe 3, and a cap-like leakage preventing member 10 arranged in a housing section 9 and comprising an elastic member filled with a liquid inside. The housing section 9 is formed in the joint 7 in such a way that an opening section 8 may be on the side of the connection member 6 and turned upward. The pressure measuring apparatus has an air intrusion preventing section for preventing air contained in the oil supply pipe 3 from passing through between the inner wall of the joint 7 and the outer wall of the leakage preventing member 10, leaking, and intruding into the leakage preventing member 10. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a pressure measuring device for measuring the pressure of high-pressure fuel oil and a combustion device equipped with the same.

  In industrial equipment and general-purpose equipment that uses a liquid inlet pressurized at a pressure higher than atmospheric pressure (hereinafter referred to as “high-pressure liquid”), a pressure gauge and pressure are usually used to grasp the state of the high-pressure liquid. A measuring device such as a detection sensor is attached. When these measuring instruments are damaged, the high pressure liquid may continuously leak and the liquid may be released around the measuring instruments.

  The applicant has proposed a pressure measuring device (see FIGS. 7 and 8) for preventing continuous leakage of high-pressure liquid from the measuring device in Patent Document 1.

  This pressure measuring device of Patent Document 1 includes a pressure gauge (2) provided with a connecting member (10) having a liquid inlet (4), a liquid supply pipe (3), and an upper end connected to the pressure gauge (2). A cylindrical joint (6) whose lower end is connected to the liquid supply pipe (3), and a housing formed in the joint (6) so that the opening (5) is on the pressure gauge (2) side and upward. And a cap-shaped leakage prevention member (1) made of an elastic member that is disposed in the portion (7) and is filled with liquid.

  A part of the cap-shaped portion of the leakage preventing member (1) forms a shielding film portion (13) due to elastic deformation, the shielding film portion (13) blocks the opening 5 and the liquid inlet (4), and The liquid supply pipe (3) side prevents the liquid from flowing into the pressure gauge (2), and the outer peripheral surface of the side part (14) of the cap-like part is the inner peripheral surface of the accommodating part (7) by elastic deformation. And the upper end of the leakage prevention member (1) is pressed against the end face of the joint (6), and the liquid exceeding the filling capacity in the pressure gauge (2) and the cap-shaped part flows out from the pressure gauge (2) to the outside. It is configured not to.

  (8) is a first screw part connected to the oil pressure gauge (2), (9) is a second screw part connected to the liquid supply pipe (3), and (11) is a leakage preventing member ( Reference numeral 1) is a pressure receiving surface, (12) is a display part of the oil pressure gauge 2, and (15) is a leg part in contact with the end face (16) of the connecting member (10).

Japanese Patent No. 4092945

  When the conventional pressure measuring device is used for measuring the pressure of the fuel oil in the boiler, the inventors of this application should display zero pressure when the oil pump is stopped and the pressurization is stopped during the boiler test operation. However, the present inventors have found a problem that a predetermined pressure is rarely displayed (hereinafter referred to as “residual pressure abnormality”).

  The problem to be solved by the present invention is to prevent a residual pressure abnormality caused by air entering the leak prevention member.

This invention was made in order to solve the said subject, and the invention of Claim 1 is a pressure measuring instrument provided with the connection member which has a liquid inlet, oil supply piping, and an upper end is the said connection member. A cylindrical joint that is connected and connected at its lower end to the oil supply pipe, and is disposed in a housing portion formed in the joint so that the opening is on the connecting member side and faces upward, and the interior is filled with liquid In the pressure measuring device provided with a cap-shaped leakage prevention member made of an elastic member,
An air intrusion prevention unit is provided that prevents air contained in the oil supply pipe from entering the leak prevention member through between the inner wall of the joint 7 and the outer wall of the leak prevention member.

  According to the first aspect of the present invention, the air contained in the oil in the oil supply pipe is prevented from entering the leakage preventing member by the air intrusion preventing unit, and a residual pressure abnormality can be prevented. .

  According to a second aspect of the present invention, in the first aspect, the air intrusion prevention portion includes an annular convex portion formed on the outer periphery of the upper end of the leak prevention member, and the annular convex portion is an inner wall of the joint. It is characterized by being pressed against.

  According to the second aspect of the present invention, it is possible to prevent the air included in the oil in the oil supply pipe from entering the leak prevention member by the annular convex portion and to prevent a residual pressure abnormality.

  The invention according to claim 3 includes a flange portion according to claim 1, wherein the joint is configured by an upper joint and a lower joint that are screw-coupled to each other, and the air intrusion prevention portion is formed in the opening. It is comprised, When the said upper joint and the said lower joint are couple | bonded, the said flange part is press-contacted to the end surface of the said upper joint, It is characterized by the above-mentioned.

  According to the third aspect of the present invention, the air contained in the oil in the oil supply pipe is prevented from entering the leak prevention member by the flange portion pressed by the upper joint, and a residual pressure abnormality is prevented. Can be prevented. In addition, since the joint is divided into two parts, and the pressure welding operation of the flange portion by the upper joint and the joining operation of the upper joint and the connecting member are separately performed, the flange portion by the upper joint Can be reliably performed.

  According to a fourth aspect of the present invention, in the first aspect, the air intrusion prevention portion is configured to include a flange portion formed in the opening, and the presser member separate from the connection member is connected to the joint. The flange portion is sometimes pressed against the end surface of the pressing member.

  According to the fourth aspect of the present invention, the air contained in the oil in the oil supply pipe is prevented from entering the leak prevention member by the flange portion press-contacted by the presser member, thereby preventing a residual pressure abnormality. can do. In addition, since the pressing operation of the flange portion by the pressing member and the joint and the connecting operation of the joint and the connecting member are separately performed, the pressing of the flange portion by the pressing member is ensured. It can be carried out.

  Furthermore, the invention according to claim 5 is an oil pump provided in the oil supply pipe, a burner to which fuel oil pressurized by the oil pump is supplied through the oil supply pipe, the oil pump and the burner. A combustion apparatus comprising the pressure measuring device according to claim 1 to 4 connected to the oil supply pipe between the two.

  According to the fifth aspect of the present invention, it is possible to prevent an abnormality in the residual pressure of the pressure measuring device that occurs when the oil pump is stopped after driving the oil pump during a trial operation of the combustion device.

  According to the present invention, it is possible to prevent a residual pressure abnormality due to air entering the leak prevention member.

It is a figure explaining the schematic structure of the combustion apparatus provided with the pressure measuring device of the first embodiment of this invention. It is principal part sectional drawing explaining the structure of 1st embodiment of the same invention. It is sectional drawing of the component of the same first embodiment. It is principal part sectional drawing explaining the structure of 2nd embodiment of this invention. It is principal part sectional drawing by decomposition | disassembly explaining the structure of the said 2nd embodiment. It is principal part sectional drawing explaining the structure of 3rd embodiment of this invention. It is principal part sectional drawing of the normal time explaining the structure of a prior art example. It is principal part sectional drawing explaining the state at the time of abnormality of a prior art example.

  The best mode for carrying out the pressure measuring apparatus according to the present invention will be described.

(First embodiment)
Hereinafter, a first embodiment of a pressure measuring device of the present invention will be described in detail with reference to the drawings. The first embodiment is a pressure measuring device 2 that is implemented in the combustion device 1. FIG. 1 is a diagram illustrating a schematic configuration of a combustion apparatus 1 including a pressure measuring device 2 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part illustrating the configuration of the first embodiment. FIG. 3 is a cross-sectional view of the component of the first embodiment.

  Referring to FIG. 1, a combustion apparatus 1 such as a boiler includes an oil pump 4 provided in an oil supply pipe 3 and a burner 5 to which fuel oil pressurized by the oil pump 4 is supplied through the oil supply pipe 3. 1 A of combustor main bodies which have and the pressure measurement apparatus 2 connected to the oil supply piping 3 between the oil pump 4 and the burner 5 are comprised.

  Referring to FIG. 2, the pressure measuring device 2 includes a connection member 6 (same as the connection member (10) of the conventional example) having a liquid inlet (not shown and the same as the liquid inlet (4) of the conventional example). A Bourdon tube type hydraulic gauge as a pressure measuring device provided (not shown, the same as the conventional hydraulic gauge (2)), and a cylinder having an upper end connected to the hydraulic gauge and a lower end connected to the oil supply pipe 3 A joint 7 and a cap-shaped leak prevention member 10 disposed in a housing portion 9 formed in the joint 7 so that the opening 8 is on the hydraulic gauge side and face upward. .

  The connecting member 6 connected to the joint 7 is provided with a passage (not shown) through which fuel oil can flow, and the liquid inlet is provided at the end on the oil supply pipe 3 side. . The connecting member 6 is formed with a first end surface 12 that contacts the leg 11 of the leakage preventing member 10 on the liquid inlet side. The distal end portion (not shown) of the connecting member 6 is formed in a shape that fits with the leg portion 12.

The leakage preventing member 10 is filled with liquid and is interposed between the oil supply pipe 3 and the oil pressure gauge, and has a function of transmitting the pressure of the fuel oil in the oil supply pipe 3 to the oil pressure gauge. . Further, the leakage preventing member 10 has a function of blocking the liquid inlet of the oil pressure gauge by being deformed by being pressed by the pressure of the fuel oil when the oil pressure gauge is damaged. That is, it has a function of preventing the outflow of liquid by blocking the liquid inlet with a part of the leakage prevention member 10 (this outflow prevention function is the same as that of Patent Document 1, and thus the description thereof is omitted). .) When the fuel oil is heavy oil, the liquid filled in the leakage preventing member 10 is kerosene different from this in the third embodiment, but can be the same oil as the fuel oil. It can be.

  Further, the configuration of the leakage preventing member 10 will be described. The leak preventing member 10 is constituted by an elastic member. The elastic member is, for example, a rubber material or a plastic material. The leak prevention member 10 is formed by molding an elastic member into a so-called cap shape and having a predetermined internal volume.

  Here, the details of the cap-like shape of the leakage preventing member 10 will be described. In this cap-like shape, first, when the connecting member 6 and the joint 7 are connected and connected to the periphery of the opening 8 on the connecting member 6 side of the cap-like portion, the first end surface 12 of the connecting member 6 is abutted against the cap member. A contact leg 12 is formed. The leg portion 11 is formed so as to be fitted to the distal end portion of the connecting member 6, and the upward projecting height of the leg portion 11 is such that the upper end surface (reference numeral omitted) is in contact with the first end surface 12 during the connection. It is the height to touch.

  Next, a pressure receiving surface 13 for receiving liquid pressure from the oil supply pipe 3 side is formed on the bottom surface of the cap-like part on the oil supply pipe 3 side. The pressure receiving surface 13 is formed such that the central portion protrudes downward. The second step portion 13 </ b> A of the pressure receiving surface 13 is configured to come into contact with the first step portion 9 </ b> A of the storage portion 9 when the leakage prevention member 10 is inserted and stored in the storage portion 9.

  The internal volume of the leakage preventing member 10 is determined as follows. The internal volume is the internal volume of the leakage prevention member 10 because the pressure of the fuel oil is accurately displayed even if air or the like is present in the oil pressure gauge. In order to compensate, the internal volume of the Bourdon tube (not shown) in the oil pressure gauge is almost the same as the internal volume.

  The joint 7 is configured in a cylindrical shape, and a housing portion 9 for housing the leakage preventing member 10 is formed in the central portion of the joint 7. The joint 7 includes a first threaded portion 14 that is connected to the connecting member 6 of the oil pressure gauge from the housing portion 9 toward the opening on the connection side with the oil pressure gauge, and is connected to the oil supply pipe 3 from the housing portion 9. A second screw portion 15 connected to the oil supply pipe 3 is provided toward the connection-side opening. And the internal diameter and length of the joint 7 are comprised so that it may become the internal diameter and length which can ensure the internal volume of the leak prevention member 10. FIG. The inner diameter of the joint 7 is set to be approximately equal to or slightly smaller than the outer diameter of the leakage preventing member 10.

  In the pressure measuring device 2 of the first embodiment, the air contained in the oil supply pipe 3 passes through the gap between the inner wall of the joint 7 and the outer wall of the leakage preventing member 10 and is in the hollow portion 12 of the leakage preventing member 10. An air intrusion prevention unit is provided to prevent intrusion. As shown in FIGS. 2 and 3, the air intrusion prevention unit includes a plurality of annular protrusions that are integrally formed with the leak prevention member 10 on the outer periphery of the upper end of the leak prevention member 10 at predetermined intervals. (The 1st convex part 17 and the 2nd convex part 18) are comprised. That is, the convex portions 17 and 18 are elastically deformed and pressed against the inner wall of the joint 7 during operation of the oil pump 3. The outer diameters of the convex portions 17 and 18 are set larger than the inner diameter of the accommodating portion 9 (for example, about 1 mm) to enhance the sealing performance. Moreover, the upper end part of the leg part 11 is opened outward, is made to protrude like a convex part, and has improved the sealing performance.

  Next, a method for assembling the pressure measuring device 2 will be described. First, the second screw portion 15 of the joint 7 is screwed into the oil supply pipe 3 to connect the oil supply pipe 3 and the joint 7. Next, the leakage preventing member 10 is pushed in from the upper side of the joint 7, that is, from the first screw portion 14 side, with the opening 8 facing upward. At this time, since the leakage preventing member 10 is an elastic member, the leakage preventing member 10 is disposed in the accommodating portion 9 even if it is slightly thicker than the inner diameter of the joint 7. Then, kerosene is filled into the leak preventing member 10 from the opening 8.

  Next, the connecting member 6 of the oil pressure gauge is connected to the first screw part so that the filling oil in the leakage preventing member 10 communicates with the oil in the oil pressure gauge, that is, the opening 8 and the liquid inlet are in communication. 14 is screwed to connect the connecting member 6 and the joint 7 of the oil pressure gauge. At this time, the leg portion 12 of the leakage preventing member 10 is fitted to the distal end portion of the connection member 6, and the upper end surface of the leg portion 12 comes into contact with the first end surface 12 of the connection member 6.

  In the above-described configuration, the leak prevention member 10 has a part of the cap-like portion of the leak prevention member 10 that forms a shielding film portion due to elastic deformation, the shielding film portion blocks the opening 8 and the liquid inlet, and oil. The liquid from the supply pipe 3 side is prevented from flowing into the oil pressure gauge, and the outer peripheral surface of the side portion of the cap-shaped portion is pressed against the inner peripheral surface of the accommodating portion 9 by the elastic deformation, and the leakage preventing member 10 The upper end of the hydraulic pressure gauge is pressed against the end face of the joint 7 so that liquid exceeding the filling capacity in the hydraulic pressure gauge and the cap-shaped portion does not flow out of the hydraulic pressure gauge. This point is the same as in Patent Document 1.

  The operation of the pressure measuring device 2 having the above configuration will be described. First, a normal measurement state will be described. In this normal measurement, when the oil pump 4 is driven, the pressure of the fuel oil is transmitted from the oil supply pipe 3 side to the pressure receiving surface 13 of the leakage preventing member 10. Next, the pressure of the fuel oil is transmitted to the filling liquid by the deformation of the leakage preventing member 10 and further to the liquid inlet side. And the pressure value of fuel oil is displayed on the display part (illustration omitted) of the oil pressure gauge.

  When the above-described convex portions 17 and 18 are not provided, the residual pressure abnormality may occur during the trial operation of the combustion apparatus 1. As a result of investigating the cause, when air is mixed in the fuel oil in the oil supply pipe 3 during the trial operation of the oil pump 3 of the combustion apparatus 1, the air floats from the oil supply pipe 3 and is connected to the joint. Accumulate within 7. As described above, when the connection member 6 and the joint 7 are connected, the leg portion 12 of the leakage preventing member 10 is fitted to the distal end portion of the connection member 6, and the upper end surface of the leg portion 12 is the first end surface of the connection member 6. 12, the accumulated air passes through the gap between the inner wall of the joint 7 and the leakage prevention member 10 → the gap between the upper end surface of the leg portion 12 and the first end surface 12 of the connecting member 6. Then, it enters the hollow portion 5 of the leakage preventing member 10. When the oil pump 4 is stopped, it is considered that the air that has entered the hollow portion 12 expands in the leakage preventing member 10 and loses the escape space, causing a residual pressure abnormality.

  According to the first embodiment provided with the convex portions 17 and 18 described above, the occurrence of the residual pressure abnormality is prevented during the trial operation of the combustion apparatus 1. Prevention of this residual pressure abnormality was confirmed by experiments. The first convex portion 17 and the second convex portion 18 are pressed against the inner peripheral wall of the joint 7 (in FIG. 2, the first convex portion 17 and the second convex portion 18 are in a crushed state), and the above-mentioned accumulation. As a result of the air being prevented from passing through the gap between the inner wall of the joint 7 and the leak preventing member 10, it is considered that the intrusion of air into the hollow portion 5 of the leak preventing member 10 is prevented.

(Second embodiment)
The present invention is not limited to the first embodiment, and can be a second embodiment shown in FIGS. In the following description of the second embodiment, the description will focus on the configuration different from that of the first embodiment, and the same components will be assigned the same reference numerals and description thereof will be omitted.

  4 and 5, the second embodiment is different from the first embodiment in that the joint 7 is composed of an upper joint 19 and a lower joint 20 that are screwed together. . And the air intrusion prevention part of the present invention is configured to include the flange part 21 formed in the opening 8, the upper joint 19, and the lower joint 20, that is, when the upper joint 19 and the lower joint 20 are screwed together. The flange 21 is pressed against the second end face 22 of the upper joint 19 to form the air intrusion prevention portion.

  Further, in the leakage preventing member 10, an annular third convex portion 24 is formed on the upper surface of the flange portion 21, and an annular concave portion 25 is formed on the second end surface 22 of the upper joint 19. Then, when the fourth threaded portion 27 of the upper joint 21 is screwed into the third threaded portion 26 of the lower joint 20 until the lower end 19A of the upper joint 19 contacts the stepped portion 20A of the lower joint 20, with a predetermined tightening margin, The flange portion 21 is compressed up and down, and the second end face 22 of the upper joint 19 is pressed against the flange portion 21 to form a first seal portion. At the same time, the third convex portion 24 is compressed by the bottom surface 28 of the concave portion 25 to form a second seal portion.

  Further, the second step portion 13A of the pressure receiving surface 13 of the leakage preventing member 10 and the first step portion 9A of the accommodating portion 9 are configured to have a predetermined interval. Reference numeral 29 denotes an annular first packing that prevents oil from flowing out of the joint 7.

  The assembly of the pressure measuring device 2 of the second embodiment is performed as follows. First, the second screw portion 15 of the lower joint 20 is screwed into the oil supply pipe 3 to connect (link) the oil supply pipe 3 and the lower joint 20. Next, the leakage prevention member 10 is pushed in from the upper side of the lower joint 20 with the opening 8 facing upward. Then, kerosene is filled into the leak preventing member 10 from the opening 8. Next, the upper joint 19 is screwed into the lower joint 20 until the lower end 19 </ b> A comes into contact with the third step portion 23. Next, the connecting member 6 is screwed into the first screw portion 14 of the upper joint 19. The connecting member 6 may be connected to the upper joint 19 in advance.

  According to the second embodiment, the air intrusion prevention portion is configured by the first seal portion and the second seal portion, and the air contained in the oil in the oil supply pipe 3 by these seal portions. Is prevented from entering the hollow portion 16 of the leakage preventing member 10. As a result, the conventional residual pressure abnormality can be prevented.

  Further, since the pressure welding operation of the flange portion 21 by the connection of the upper joint 19 and the lower joint 20 and the connection operation of the upper joint 19 and the connecting member 6 are performed separately, the predetermined tightening of the flange portion 21 is performed. Thus, the flange portion 21 can be compressed by the upper joint 19, the flange portion 21 can be reliably pressed by the upper joint 19, and air can be prevented from entering.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the following description of the third embodiment, the configuration different from that of the first embodiment will be mainly described, the same components are denoted by the same reference numerals, and the description thereof will be omitted.

  The third embodiment differs from the first embodiment in that the air intrusion prevention portion of the present invention includes a flange portion 21 formed in the opening portion 8 of the leak prevention member 10, an annular pressing member 30, and the joint 7. It consists of.

  That is, the third embodiment includes a pressing member 30 that is separate from the connecting member 6 of the hydraulic gauge, and the joint 7 is formed by extending the first screw portion 14 for screwing the connecting member 6. ing. Then, on the outer periphery of the pressing member 30, a screw portion (reference numeral omitted) that is screwed with the extended first screw portion 14 is formed, and a fourth step portion 31 is formed. Further, on the joint 7 side, a fifth step portion 32 that contacts the fourth step portion 31 is formed. The heights of the fourth step portion 31 and the second step portion 32 are set so that the flange portion 21 is compressed with a predetermined margin in a state where the fourth step portion 31 and the fifth step portion 32 are in contact with each other. Is done.

Thus, when the presser member 30 is screwed into the joint 7, the flange portion 21 is pressed against the third end surface 33 of the presser member 30 to form the air intrusion prevention portion of the present invention. The presser member 30 is configured to be screwed with an appropriate tool (including a jig).

  Reference numeral 34 denotes an annular second packing for sealing between the lower end surface of the connection member 6 and the upper end surface of the pressing member 30, and is accommodated in an annular concave groove (reference numeral omitted) formed on the upper surface of the pressing member 30. Arranged

  The assembly of the pressure measuring device 2 of the third embodiment is performed as follows. First, the second screw portion 15 of the joint 7 is screwed into the oil supply pipe 3 to connect the oil supply pipe 3 and the joint 7. Next, the leak preventing member 10 is pushed in from the upper side of the joint 7 in a state where the opening portion 8 faces upward. Then, kerosene is filled into the leak preventing member 10 from the opening 8. Next, the pressing member 30 is screwed into the first screw portion 14 until the fourth step portion 31 comes into contact with the fifth step portion 32 of the joint 7. Next, the connecting member 6 is screwed into the first screw portion 14 of the joint 7.

  According to the third embodiment, the air contained in the oil in the oil supply pipe 3 is prevented from entering the hollow portion 16 of the leakage preventing member 10 by the pressure contact of the flange portion 21 by the pressing member 30. As a result, the conventional residual pressure abnormality can be prevented.

  Further, since the pressing work of the flange portion 21 by the connection of the presser member 30 and the joint 7 and the connecting work of the joint 7 and the connecting member 6 are performed separately, the presser can be pressed with a predetermined tightening margin. The flange portion 21 can be compressed by the member 30, the flange portion 21 can be reliably pressed by the pressing member 30, and air can be prevented from entering.

  The present invention is not limited to the first to third embodiments. For example, in the first embodiment, two protrusions are provided. . Further, by providing the leakage preventing member 10 of the second embodiment and the third embodiment with the convex portions 17 and 18 of the first embodiment, the effect of preventing air intrusion can be further enhanced. Furthermore, in 3rd embodiment, the air penetration | invasion prevention effect can be heightened further by providing the 3rd convex part 24 and the recessed part 25 of 2nd embodiment.

DESCRIPTION OF SYMBOLS 1 Combustion apparatus 2 Pressure measuring apparatus 3 Oil supply piping 4 Oil pump 6 Connection member 7 Joint 8 Opening part 10 Leakage prevention member 17 1st convex part (air intrusion prevention part)
18 Second convex part (air intrusion prevention part)
19 Upper joint 20 Lower joint 21 Flange (air intrusion prevention part)
22 Second end face (end face)
30 Presser member 32 Third end face (end face)

Claims (5)

A pressure measuring device provided with a connecting member having a liquid inlet; an oil supply pipe; a cylindrical joint whose upper end is connected to the connecting member and whose lower end is connected to the oil supply pipe; and an opening is on the connecting member side In the pressure measuring device provided with a cap-shaped leakage prevention member made of an elastic member that is disposed in the accommodating portion formed in the joint so as to be upward and filled with liquid,
A pressure comprising an air intrusion prevention portion for preventing air contained in the oil supply pipe from entering the leak prevention member through between the inner wall of the joint 7 and the outer wall of the leak prevention member. measuring device.   The said air intrusion prevention part is comprised including the annular convex part formed in the upper-end outer peripheral part of the said leakage prevention member, This annular convex part is press-contacted to the inner wall of the said joint. Pressure measuring device. The joint is composed of an upper joint and a lower joint that are screwed together,
The air intrusion prevention portion includes a flange portion formed in the opening, and the flange portion is press-contacted to an end surface of the upper joint when the upper joint and the lower joint are coupled. The pressure measuring device according to claim 1.   The air intrusion prevention part includes a flange part formed in the opening part, and the flange part is pressed against the end surface of the presser member when the presser member separate from the connection member is connected to the joint. The pressure measuring device according to claim 1.   An oil pump provided in the oil supply pipe, a burner to which fuel oil pressurized by the oil pump is supplied through the oil supply pipe, and the oil supply pipe between the oil pump and the burner are connected. The combustion apparatus provided with the pressure measuring apparatus 2 of Claims 1-4.

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