Pressure sensor and pressure measuring apparatus

Abstract

To provide a pressure sensor in which pressure introducing pipes inside washers are not corroded.SOLUTION: A pressure sensor includes: a sensor case that accommodates a pressure sensor chip; first and second pressure introducing pipes 3, 4 whose one end portion is inserted into an opening of a hole of the sensor case and soldered thereto and which transmit pressure to be measured to the pressure sensor chip; and first and second washers 5, 6 in which the first and second pressure introducing pipes 3, 4 are inserted into third and fourth through holes 28, 29 and welded. A connection portion between the sensor case and the first and second pressure introducing pipes 3, 4 is sealed with solder. Materials of the first and second pressure introducing pipes 3, 4 inserted into the third and fourth through holes 28, 29 are exposed. Gaps between one ends of the third and fourth through holes 28, 29 and the first and second pressure introducing pipes 3, 4 are sealed with a sealing material 31. Au plating 33 for soldering is applied to an entire region except for portions to which the sealing material 31 is bonded on outer surfaces of the first and second washers 5, 6.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a pressure sensor provided with a pressure guiding tube that transmits a pressure to be measured to a sensor chip, and a pressure measuring device provided with this pressure sensor. [Background technology]

[0002] An example of a pressure sensor equipped with a pressure guiding tube for transmitting the pressure to be measured is described in Patent Document 1. The pressure sensor disclosed in Patent Document 1 includes a sensor case connected to one end of the pressure guiding tube and a washer connected to the other end of the pressure guiding tube. The sensor case houses a pressure sensor chip and has a hole for connecting the pressure guiding tube formed at a position corresponding to the pressure-receiving portion of the pressure sensor chip. The pressure guiding tube is inserted into this hole and soldered to the sensor case. To ensure reliable soldering, the pressure guiding tube is gold-plated and the sensor case is metallized.

[0003] The washer is welded to the body of the pressure measuring device and has a through hole through which the pressure guiding tube is inserted. The tip of the pressure guiding tube is welded to the washer while inserted into the through hole. The assembly consisting of the pressure guiding tube and washer is subjected to the above-mentioned gold plating after the washer is welded to the pressure guiding tube. The pressure guiding tube is made of stainless steel, and when gold plating is applied to this pressure guiding tube, it is immersed in an acid treatment solution to remove the oxide film. Gold plating is performed by immersing the assembly consisting of the pressure guiding tube and washer in a tank containing plating solution. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-99901 Summary of the Invention [Problem to be solved by the invention]

[0005] Immediately after the washer is welded to the pressure conductor, a small gap is formed between the pressure conductor and the opening of the through-hole in the washer through which the pressure conductor is inserted. Therefore, in conventional pressure sensors, there is a risk that an acidic treatment solution or plating solution may enter this small gap and remain as a residue. If the acidic treatment solution or plating solution remains as a residue in the small gap between the pressure conductor and the washer, the residue corrodes the pressure conductor inside the washer. As this corrosion progresses, the pressure resistance of the pressure conductor may deteriorate, potentially damaging the pressure sensor.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure sensor and a pressure measuring device in which the pressure guiding tube in the washer is not corroded. [Means for solving the problem]

[0007] In order to achieve this object, the pressure sensor of the present invention comprises a sensor case that houses a pressure sensor chip and has an opening at a position corresponding to the pressure-receiving portion of the pressure sensor chip; a pressure guiding tube, one end of which is inserted into the opening of the hole and soldered to transmit the pressure to be measured to the pressure sensor chip; and a washer that has a through hole, one end of which is inserted into the through hole and the other end of which is welded to the pressure guiding tube at the other end of the through hole, wherein the connection between the sensor case and the pressure guiding tube is sealed with solder that comes into contact with the soldering plating applied to the pressure guiding tube, the other end of the pressure guiding tube inserted into the through hole exposes the material of the pressure guiding tube, and the gap between the one end of the through hole and the pressure guiding tube is sealed with a sealant, and the soldering plating is applied to the entire outer surface of the washer except for the portion where the sealant is adhered.

[0008] In the pressure sensor of the present invention, the sealing material may be a fluorine-based adhesive.

[0009] In the pressure sensor of the present invention, the sealing material may be a brazing material.

[0010] In the pressure sensor of the present invention, the sealing material may be solder.

[0011] The pressure measuring device of the present invention is a pressure measuring device equipped with the pressure sensor, and comprises a pressure sensor accommodating section formed in a bottomed cylindrical shape that opens upward, with a pressure guide path through which the pressure of the fluid to be measured is transmitted opening at the inner bottom, and a cover attached to the opening of the pressure sensor accommodating section and cooperating with the pressure sensor accommodating section to form a sealed housing, with the washer welded to the inner bottom so that the pressure guide tube is connected to the pressure guide path. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a pressure sensor and a pressure measuring device in which the pressure guiding tube inside the washer is not corroded. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a pressure sensor according to the present invention. [Figure 2] FIG. 2 is a perspective cross-sectional view of the sensor case. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing a part of the sensor case and the pressure guiding pipe. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing a part of the washer and the pressure guiding tube. [Figure 5] FIG. 5 is a perspective cross-sectional view showing the main part of the pressure measuring device in a cutaway manner. [Figure 6] FIG. 6 is a diagram for explaining the procedure for manufacturing an assembly consisting of a pressure guiding tube and a washer. [Figure 7] FIG. 7 is a cross-sectional view illustrating a procedure for assembling the sensor case. [Figure 8] FIG. 8 is a cross-sectional view showing another example of the sealing material. [Figure 9] FIG. 9 is a cross-sectional view showing another example of the sealing material. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a pressure sensor and a pressure measuring device according to the present invention will be described in detail with reference to FIGS. The pressure sensor package 1 shown in FIG. 1 constitutes the "pressure sensor" of the present invention, and includes a sensor case 2 formed to have a cubic appearance, first and second pressure guiding tubes 3 and 4, and first and second washers 5 and 6.

[0015] As shown in FIG. 2 , the sensor case 2 is composed of a case body 11 formed in the shape of a rectangular cylinder with a bottom, and a lid 12 that closes the opening of the case body 11. The case body 11 is made of a ceramic material, and the lid 12 is made of a ceramic material or a metal material. A first through hole 14 and a second through hole 15 are formed in the bottom wall 13 of the case body 11. One end of a first pressure guiding tube 3 and one end of a second pressure guiding tube 4 are inserted into these first and second through holes 14, 15. These first and second pressure guiding tubes 3, 4 are connected to a pressure sensor chip 16 housed in the sensor case 2.

[0016] The pressure sensor chip 16 is formed into a cube by stacking multiple silicon plate-like members in the thickness direction. The pressure sensor chip 16 is formed with a first hole 17 into which the first pressure guiding tube 3 is inserted and a second hole 18 into which the second pressure guiding tube 4 is inserted. The inside of the first hole 17 is connected to a first pressure chamber 16a (see FIG. 3) which serves as one pressure receiving portion of the pressure sensor chip 16, and the inside of the second hole 18 is connected to a second pressure chamber 16b which serves as the other pressure receiving portion of the pressure sensor chip 16.

[0017] The first through-hole 14 of the case body 11 is formed at a position corresponding to the first pressure chamber 16a and the first hole 17. The second through-hole 15 is formed at a position corresponding to the second pressure chamber 16b and the second hole 18. The pressure sensor chip 16 according to this embodiment is configured to detect the differential pressure between the measured pressure transmitted from the first hole 17 to the first pressure chamber 16a and the measured pressure transmitted from the second hole 18 to the second pressure chamber 16b.

[0018] The first and second pressure guiding pipes 3 and 4 are each made of stainless steel and bent into a predetermined shape. As shown in FIG. 3, the first and second pressure guiding pipes 3 and 4 are bonded to the pressure sensor chip 16 with adhesive 19. The inside of the sensor case 2 is in a vacuum state or filled with N2 The sensor case 2 is kept filled with an inert gas such as a gas. To maintain this inert state inside the sensor case 2, the cover 12 is welded or brazed to the sensor case 2, and the portions of the first and second pressure guiding tubes 3 and 4 that pass through the first and second through holes 14 and 15 of the sensor case 2 are sealed by soldering. The pressure guiding tube pass-through portions are soldered so that the solder 20 wets and spreads over the entire area around the first and second through holes 14 and 15.

[0019] More specifically, the first and second through-holes 14, 15 of the case body 11 and the peripheries of the openings of these first and second through-holes 14, 15 are metallized. Furthermore, the portions of the first and second pressure guiding tubes 3, 4 that are inserted into the first and second through-holes 14, 15 are plated for soldering. This soldering plating is Au plating on a Ni base. In other words, the connections between the sensor case 2 and the first and second pressure guiding tubes 3, 4 are sealed by solder 20 that comes into contact with the Au plating for soldering that is applied to the first and second pressure guiding tubes 3, 4.

[0020] As shown in Fig. 2, bonding pads 21 are provided on the inside of the sensor case 2. These bonding pads 21 are electrically connected to bonding pads 22 of the pressure sensor chip 16 via bonding wires 23. The bonding pads 21 of the sensor case 2 are also electrically connected to electrodes 24 (see Fig. 1) provided on the outer bottom surface of the sensor case 2 via conductors within the sensor case 2. The electrodes 24 of the sensor case 2 are soldered to soldering lands on a substrate indicated by reference numeral 25 in Fig. 5. The substrate 25 is supported by a body 27 of a pressure measuring device 26 shown in Fig. 5 via a bracket (not shown). The pressure measuring device 26 will be described later.

[0021] The first and second washers 5 and 6 of the pressure sensor package 1 are used to attach the pressure sensor package 1 to the body 27 of the pressure measuring device 26. The first and second washers 5 and 6 are each formed into a disk shape from stainless steel. As shown in FIG. 4, cylindrical protrusions 5a and 6a are provided in the center of the first and second washers 5 and 6, and third and fourth through holes 28 and 29 are formed therein.

[0022] The other end of the first impulse guiding pipe 3 is inserted from one end into the third through-hole 28 formed in the first washer 5. The first washer 5 is welded to the first impulse guiding pipe 3 at the other end of the third through-hole 28. The other end of the second impulse guiding pipe 4 is inserted from one end into a fourth through-hole 29 formed in the second washer 6. The second washer 6 is welded to the second impulse guiding pipe 4 at the other end of the fourth through-hole 29. More specifically, the outer peripheries of the tips of the first and second impulse guiding pipes 3 and 4 are welded to the opening edges of the third and fourth through holes 28 and 29 that open into the protrusions 5a and 6a of the first and second washers 5 and 6. This welding is performed so that welds 30 form a liquid-tight seal between the first and second washers 5 and 6 and the first and second impulse guiding pipes 3 and 4, as shown in Figure 4.

[0023] The material of the impulse guiding pipes is exposed at the other ends of the first and second impulse guiding pipes 3, 4, i.e., the portions inserted into the third and fourth through holes 28, 29. In other words, the other ends of the first and second impulse guiding pipes 3, 4 are welded to the first and second washers 5, 6 without being plated with Au. Therefore, weld cracks do not occur in this welded portion 30 due to P (phosphorus) or S (sulfur) contained in the Ni plating components of the underlying Au plating.

[0024] The ends of the third and fourth through holes 28, 29, into which the first and second impulse guiding tubes 3, 4 are inserted, are sealed with a sealant 31 while the first and second washers 5, 6 are welded to the first and second impulse guiding tubes 3, 4. In other words, the gaps between the ends of the third and fourth through holes 28, 29 and the first and second impulse guiding tubes 3, 4 are sealed with the sealant 31. The sealant 31 can be made of a fluorine-based adhesive, brazing material, solder, or the like. The fluorine-based adhesive can be a coating agent or a potting agent. Figure 4 shows a cross-sectional view of a case where a potting agent 32, which is a type of fluorine-based adhesive, is used as the sealant 31.

[0025] The outer surfaces of the first and second washers 5 and 6 are coated with Au plating 33 in the areas indicated by hatching slanting downward to the left in Fig. 4. More specifically, the Au plating 33 is coated on the entire outer surfaces of the first and second washers 5 and 6 except for the areas where the sealing material 31 is bonded.

[0026] As shown in Fig. 5, the pressure measuring device 26 has a body 27 shown on the lower side of Fig. 5 and a cylindrical cover 34 with a bottom attached to the body 27, and is configured by assembling the pressure sensor package 1 and a bracket (not shown) that supports the substrate 25 to the body 27. The cover 34 is attached to the body 27 via a sealing structure (not shown) with its opening in contact with the body 27. The upper part of the cover 34 is omitted in Fig. 5. The pressure measuring device 26 is used in a position where the body 27 is located below the cover 34 .

[0027] The body 27 is formed by a pressure receiving portion 35 shown at the bottom in FIG. 5 and a pressure sensor accommodating portion 36 provided above the pressure receiving portion 35. A first diaphragm 37 that contacts a first fluid to be measured (not shown) is provided at one end (the right end in FIG. 1) of the pressure-receiving part 35, and a second diaphragm 38 (see FIG. 2) that contacts a second fluid to be measured (not shown) is provided at the other end. The first and second fluids to be measured are introduced into pipes (not shown) connected to both ends of the body 27.

[0028] Formed inside the body 27 are a first pressure receiving chamber 39, the wall of which is formed by the first diaphragm 37, a second pressure receiving chamber 40, the wall of which is formed by the second diaphragm 38, a first pressure guide path 41 extending from the first pressure receiving chamber 39 to the pressure sensor housing 36, and a second pressure guide path 42 extending from the second pressure receiving chamber 40 to the pressure sensor housing 36. The first and second pressure receiving chambers 39, 40 and the first and second pressure guide paths 41, 42 are filled with a pressure transmission medium (not shown). The first and second pressure guide tubes 3, 4 and the pressure sensor chip 16 are also filled with a pressure transmission medium.

[0029] The pressure sensor housing 36 of the body 27 cooperates with the cover 34 to form the housing 43, which is a sealed container. The pressure sensor housing 36 is formed in a cylindrical shape with a bottom that opens upward so as to form the lower part of the housing 43. The opening at the upper end of the pressure sensor housing 36 overlaps the opening of the cover 34 and is closed by the cover 34. A sealing member (not shown) is provided between the pressure sensor housing 36 and the cover 34.

[0030] The pressure sensor housing 36 according to this embodiment is formed by a cylinder 44 extending in the vertical direction and a bottom wall 45 that closes the lower end of the cylinder 44. The bottom wall 45 forms the inner bottom of the pressure sensor housing 36. The first pressure guide path 41 and the second pressure guide path 42 open into the bottom wall 45, and a pair of screw holes 46 are formed in the bottom wall 45. A bracket that supports the substrate 25 is placed on the bottom wall 45 and fixed to the bottom wall 45 by fixing bolts that are screwed into the screw holes 46. First and second washers 5, 6 are welded to the portion of bottom wall 45 where first pressure guide path 41 opens and to the portion where second pressure guide path 42 opens, respectively.

[0031] By welding the first washer 5 to the bottom wall 45, the first pressure guiding path 41 is connected to the first pressure guiding tube 3, allowing the pressure to be measured of the first fluid to be transmitted to the pressure sensor chip 16. By welding the second washer 6 to the bottom wall 45, the second pressure guiding path 42 is connected to the second pressure guiding tube 4, allowing the pressure to be measured of the second fluid to be transmitted to the pressure sensor chip 16. The first and second pressure guiding tubes 3 and 4 are bent to extend horizontally above the first and second washers 5 and 6. Therefore, the mounting surface of the sensor case 2, which has the electrodes 24, extends vertically. The sensor case 2 according to this embodiment is mounted on a substrate 25 that is in an upright position so as to extend vertically.

[0032] Next, the procedure for assembling the pressure sensor package 1 according to this embodiment will be described with reference to Figures 6(A) to (D) and Figures 7(A) and (B). Figure 6(A) is a side view showing the welding step, Figure 6(B) is a cross-sectional view showing the sealing step, Figure 6(C) is a cross-sectional view showing the plating step, and Figure 6(D) is a side view showing the cleaning step. Figure 7(A) is a cross-sectional view showing the step of connecting a pressure guiding tube to the pressure sensor chip, and Figure 7(B) is a cross-sectional view showing the step of housing the pressure sensor chip in the case body.

[0033] First, as shown in FIG. 6(A), the first and second washers 5 and 6 are welded to the first and second impulse guiding pipes 3 and 4. The first and second impulse guiding pipes 3 and 4 are not plated for soldering, leaving their bare surfaces exposed. After the first and second washers 5 and 6 are welded to the first and second impulse guiding pipes 3 and 4, a sealant application nozzle 47 is brought close to the portions of the first and second impulse guiding pipes 3 and 4 that protrude from the first and second washers 5 and 6, as shown in FIG. 6(B), and potting material 32 is dispensed from the nozzle 47. The potting material 32 is applied so that it bulges above the first and second washers 5 and 6. The potting material 32 is then cured, sealing the gaps between the third and fourth through holes 28 and 29 and the first and second impulse guiding pipes 3 and 4 with the sealant 31. In the process of forming the sealing material 31, the portions of the first and second pressure guiding tubes 3 and 4 that are inserted into the third and fourth through holes 28 and 29 are in an exposed state.

[0034] After sealing with the sealant 31, the assembly consisting of the first impulse guiding tube 3 and first washer 5 and the assembly consisting of the second impulse guiding tube 4 and second washer 6 are immersed in an acid treatment solution in an acid treatment tank (not shown) for acid treatment. Then, as shown in FIG. 6(C), the assembly is inserted into a plating tank 51 and immersed in a plating solution 52 in the plating tank 51. The plating solution 52 is used to apply Au plating for soldering. Then, Au plating for soldering is applied to the first and second impulse guiding tubes 3 and 4 by electroplating or electroless plating. At this time, the first and second washers 5 and 6 are also plated for soldering. That is, the entire outer surfaces of the first and second washers 5 and 6 are plated for soldering 33 except for the portions where the sealant 31 is attached.

[0035] Thereafter, as shown in FIG. 6(D), the assembly consisting of the first pressure guiding tube 3 and first washer 5 and the assembly consisting of the second pressure guiding tube 4 and second washer 6 are washed with, for example, a cleaning solution 53. This washing is performed including the interiors of the first and second pressure guiding tubes 3 and 4. After this post-plating washing, as shown in FIG. 7(A), the first and second pressure guiding tubes 3 and 4 are passed through the first and second through-holes 14 and 15 of the case body 11 and inserted into the first hole 17 and second hole 18 of the pressure sensor chip 16. The first and second pressure guiding tubes 3 and 4 are then bonded to the pressure sensor chip 16 with adhesive 19, and the pressure sensor chip 16 is inserted into the case body 11 as shown in FIG. 7(B).

[0036] Next, the first and second pressure guiding tubes 3, 4 are soldered to the case body 11. By soldering the first and second pressure guiding tubes 3, 4 to the case body 11, the first and second through holes 14, 15 are sealed with solder 20 (see FIG. 3). After that, the bonding pads 21 of the case body 11 are connected to the bonding pads 22 of the pressure sensor chip 16 with bonding wires 23. Next, the lid 12 is joined to the opening of the case body 11 by seam welding or brazing, sealing the case body 11. When joining the lid 12 to the case body 11, the case body 11 and the lid 12 are loaded into a chamber (not shown), and the chamber is filled with an inert gas atmosphere or is in a vacuum state. By joining the lid 12 to the case body 11, the pressure sensor package 1 is completed.

[0037] In the pressure sensor package 1 configured as described above, the gap between one end of the third through-hole 28 in the first washer 5 and the first pressure guiding tube 3, and the gap between one end of the fourth through-hole 29 in the second washer 6 and the second pressure guiding tube 4 are each sealed with a sealant 31. Therefore, during acid treatment or Au plating, the acid treatment solution or plating solution does not infiltrate into the minute gaps between the first and second pressure guiding tubes 3, 4 and the first and second washers 5, 6. Therefore, no acidic treatment solution or plating solution remains as residue, and therefore it is possible to provide a pressure sensor and a pressure measuring device in which the pressure guiding tube in the washer is not corroded.

[0038] The pressure measuring device 26 according to this embodiment includes the pressure sensor package 1 described above, and includes a pressure sensor housing 36 formed in a cylindrical shape with a bottom that opens upward, and a cover 34 that cooperates with the pressure sensor housing 36 to form a sealed housing 43. First and second pressure guiding paths 41, 42, through which the pressure of the fluid to be measured is transmitted, open into a bottom wall 45 (inner bottom) of the pressure sensor housing 36. First and second washers 5, 6 are welded to the first and second pressure guiding paths 41, 42 so that the first and second pressure guiding tubes 3, 4 are connected to these first and second pressure guiding paths 41, 42.

[0039] In the sealed housing 43 of this pressure measuring device 26, if the sealing member that seals between the pressure sensor housing 36 and the cover 34 deteriorates, moisture or rainwater from the factory may seep into the housing 43. Water that seeps into the housing 43 collects at the bottom inside the pressure sensor housing 36. Even if this water increases and submerges the first and second washers 5, 6 and the lower ends of the first and second impulse guiding pipes 3, 4, the sealant 31 prevents water from seeping into the third and fourth through-holes 28, 29, and therefore the first and second impulse guiding pipes 3, 4 inserted into the first and second washers 5, 6 will not be corroded by the water seepage. Therefore, the sealing material 31 also functions as a protective member that protects the tip ends of the first and second pressure guiding tubes 3 and 4 from the surrounding environment.

[0040] In this embodiment, an example is shown in which a potting agent 32, which is a type of fluorine-based adhesive, is used as the sealing material 31. When using the potting agent 32, the sealing material 31 can be easily formed into a convex shape, as shown in FIG. 6(B). The convex shape here refers to a generally conical shape that gradually decreases in size with increasing distance from the first and second washers 5 and 6. By forming the sealing material 31 into a convex shape, even if water flows down the first and second pressure guiding tubes 3 and 4 inside the pressure measuring device 26, the water will flow downward without being stopped by the sealing material 31. This prevents water from seeping between the sealing material 31 and the first and second pressure guiding tubes 3 and 4 or between the sealing material 31 and the first and second washers 5 and 6. This effect can be similarly obtained even when a coating agent, brazing material, solder, or the like is used as the sealing material 31. As the sealing material 31, a brazing material 61 can be used as shown in FIG. 8, or a solder 62 can be used as shown in FIG. [Explanation of symbols]

[0041] 1...pressure sensor package (pressure sensor), 2...sensor case, 3...first pressure guiding tube, 4...second pressure guiding tube, 5...first washer, 6...second washer, 14...first through hole, 15...second through hole, 16...pressure sensor chip, 16a...first pressure chamber (pressure receiving portion), 16b...second pressure chamber (pressure receiving portion), 20, 62...solder, 28...third through hole, 29...fourth through hole, 31...sealing material, 33...Au plating for soldering, 34...cover, 36...pressure sensor accommodating portion, 41...first pressure guiding path, 42...second pressure guiding path, 43...housing, 45...bottom wall (inner bottom), 61...brazing material.

Claims

1. a sensor case that accommodates a pressure sensor chip and has a hole that opens at a position corresponding to a pressure receiving portion of the pressure sensor chip; a pressure guiding tube, one end of which is inserted into the opening of the hole and soldered thereto, for transmitting the pressure to be measured to the pressure sensor chip; a washer having a through hole, into which the other end of the pressure guiding pipe is inserted from one end of the through hole and welded to the pressure guiding pipe at the other end of the through hole; a connection between the sensor case and the pressure guiding tube is sealed by solder that comes into contact with a soldering plating applied to the pressure guiding tube; the other end of the pressure guiding tube inserted into the through hole has a material of the pressure guiding tube exposed; a gap between the one end of the through hole and the pressure guiding tube is sealed with a sealant; A pressure sensor characterized in that the plating for soldering is applied to the entire outer surface of the washer except for the portion where the sealing material is adhered.

2. 2. The pressure sensor according to claim 1, The pressure sensor is characterized in that the sealing material is a fluorine-based adhesive.

3. 2. The pressure sensor according to claim 1, The pressure sensor is characterized in that the sealing material is a brazing material.

4. 2. The pressure sensor according to claim 1, The pressure sensor is characterized in that the sealing material is solder.

5. A pressure measuring device equipped with the pressure sensor according to any one of claims 1 to 4, a pressure sensor housing formed in a cylindrical shape with a bottom that opens upward, and a pressure guide path through which the pressure of the fluid to be measured is transmitted, the pressure sensor housing opening at the inner bottom; a cover attached to an opening of the pressure sensor housing and cooperating with the pressure sensor housing to form a sealed housing; A pressure measuring device characterized in that the washer is welded to the inner bottom part so that the pressure guiding pipe is connected to the pressure guiding path.

Images