JP2002296135A - Pressure detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small and compact device and stably measure both positive pressure and negative pressure with high accuracy. SOLUTION: The pressure detecting device 1, which is composed of a unit mounting member 3 being mounted at a prescribed mount position Xc of a containing section 2 wherein a medium to be measured L is contained and having a pressurized space 4, and a pressure detecting unit 5 being attachable to and detachable from the unit mounting member 3 and having a pressure detecting surface 6 facing the pressurized space 4 at an end section Fs, includes a seal holding member 7 that is disposed from the unit mounting member 3 to the pressurized space 4, a seal member 8 that is disposed between the seal holding member 7 and the end section Fs, and a fixing member 9 that can fix the pressure detecting unit 5 to the unit mounting member 3 through the seal member 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting device provided with a pressure detecting unit which can be attached to and detached from a unit mounting portion mounted on a housing for housing a measurement medium.

[0002]

2. Description of the Related Art Conventionally, a unit mounting portion which is attached to a predetermined mounting portion of a housing portion for housing a measuring medium and has a pressure action space, is detachably attached to the unit mounting portion, and has an end face portion in a pressure action space. Pressure sensing devices comprising a pressure sensing unit having a facing pressure sensing surface are known,
Japanese Patent Application Laid-Open No. 8-233676 discloses a ceramic pressure sensor, a casing, and a connection for fixing a device for measuring a pressure or a differential pressure to a wall of a container having a measurement medium detachably connected to the casing. A member, an outer sealing member inserted on the side facing the measurement medium between the casing and the pressure sensor, and exchangeably arranged between the pressure sensor and the connecting member, and An inner sealing member arranged coaxially, so that it is particularly suitable for highly viscous and / or sticky foodstuffs and can be easily cleaned without compromising the electrical properties. An apparatus is disclosed.

[0003]

However, the above-mentioned conventional apparatus has the following problems.

First, an outer sealing member for sealing between the casing and the pressure sensor and an inner sealing member for sealing between the pressure sensor and the connecting member are required, and the pressure sensor is arranged inside the casing. For this reason, it is difficult to secure a pressure detection surface having a sufficient area that is effective, and the shape of the pressure detection surface on the radially outer side becomes large, resulting in an increase in the size of the entire apparatus.

Second, the inner sealing member for sealing between the pressure sensor and the connecting member is in direct contact with the measurement medium, but the sealing member is not stably held. When the pressure is applied, the position of the seal member is displaced, so that stable high-precision measurement cannot be performed and negative pressure measurement cannot be performed.

The present invention has been made to solve the problems existing in the prior art, and realizes a compact and compact apparatus as a whole, and stably measures both positive pressure and negative pressure with high accuracy. It is an object of the present invention to provide a pressure detection device capable of performing the above.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a unit mounting portion 3 which is mounted on a predetermined mounting portion Xc of a storage portion 2 in which a measurement medium L is stored and has a pressure action space 4; When configuring the pressure detecting device 1 including the pressure detecting unit 5 which is attached to and detached from the unit attaching portion 3 and has a pressure detecting surface 6 facing the pressure acting space 4 on the end face portion Fs, the pressure acting space from the unit attaching portion 3 4, a sealing member 8 interposed between the sealing member holding portion 7 and the end face Fs, and the pressure detection unit 5 can be fixed to the unit mounting portion 3 with the sealing member 8 interposed. It is characterized by having a simple fixing tool 9.

In this case, according to a preferred embodiment, the seal member 8 is brought into contact with the non-pressure detecting surface Fn of the end face Fs. Further, a regulating wall portion 11 for regulating the position of the sealing member 8 can be provided at the tip of the sealing member holding portion 7.
In addition, instead of providing the regulating wall portion 11, the sealing member 8
In addition, a restriction piece 12 that is locked to the pressure detection unit 5 or the unit mounting section 3 and whose position is restricted may be provided. The pressure detection unit 5 further includes a pressure sensor 13 having a pressure detection surface 6, a casing portion 14 fixed to the pressure sensor 13 and forming a closed space Si facing a reference pressure application surface of the pressure sensor 13. A communication member 15 for communicating the closed space Si with the reference pressure space (atmosphere) can be provided. On the other hand, the fixing tool 9 may use a fixing device 18 for simultaneously sandwiching and fixing the connecting flange portion 16 provided on the pressure detecting unit 5 and the connecting flange portion 17 provided on the unit mounting portion 3. And a cylindrical fixing ring 19 that is screwed to the unit mounting portion 3 and locked to the unit mounting portion 3 may be used.

As a result, a single sealing member 8 is preferably provided between the pressure detecting unit 5 and the unit mounting portion 3, preferably, the non-pressure detecting surface F of the end face Fs of the pressure detecting unit 5.
n to seal with a single seal member 8 that contacts
The whole device can be made smaller and more compact. Further, according to a preferred embodiment, a regulating wall portion 11 for regulating the position of the seal member 8 is provided at the tip of the seal member holding portion 7, or the seal member 8 is locked to the pressure detection unit 5 or the unit mounting portion 3. If the restricting piece 12 whose position is regulated is provided, the seal member 8 is held at a fixed position regardless of the pressure state, and both positive pressure and negative pressure can be measured with high accuracy and stability.

[0010]

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

First, components used in the pressure detecting device 1 according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 1, the pressure detecting device 1 includes a unit mounting portion 3, a seal member 8, a pressure detecting unit 5, and a fixture 9 as constituent parts.

The unit mounting portion 3 includes a cylindrical holder portion 21 having a pressure acting space 4 inside, a ring-shaped coupling flange portion 17 provided outward from the upper end of the outer peripheral surface of the holder portion 21, and a holder portion. A ring-shaped mounting flange portion 22 provided outward from the lower end of the outer peripheral surface of the outer peripheral surface 21 and a ring-shaped sealing member holding portion provided inwardly from the lower end of the inner peripheral surface of the holder portion 21 and having the regulating wall portion 11 at the front end; 7 which are integrally formed. As a material for forming the unit mounting portion 3, a metal having a high corrosion resistance, a synthetic resin having a high corrosion resistance, or the like can be used in addition to a general metal, particularly when the measurement medium L has a corrosive property. Stainless steel, Hastelloy, titanium, tantalum, monel, nickel, inconel and the like can be used as the metal having high corrosion resistance, and polytetrafluoroethylene and the like can be used as the synthetic resin having high corrosion resistance.

The unit mounting portion 3 includes a sealing member holding portion 7
Since the regulating wall 11 for regulating the position of the seal member 8 is provided at the tip of the seal member 8, the position of the seal member 8 can be prevented from being shifted toward the center. In particular, when used in the food industry, the pressure detection surface 6 of the pressure detection unit 5 (pressure sensor 13) is often exposed to vacuum, and if the seal member 8 is displaced, an output error may occur. is there. However, since the sealing member 8 is regulated to the fixed position by providing the regulating wall 11, both the positive pressure and the negative pressure can be measured with high accuracy and stability. Further, a contact surface 11s of the regulating wall portion 11 which is in contact with the measurement medium L is formed as a curved surface (see FIG. 4). Thereby, the liquid pool of the measurement medium L can be avoided, and the cleaning is facilitated. Further, the seal member holding portion 7 is large in size so that the held seal member 8 abuts on the non-pressure detecting surface Fn of the end face portion Fs of the pressure detection unit 5, that is, on the outer peripheral side of the end face portion Fs. Choose the right. The non-pressure detection surface Fn includes both a portion that is not sensitive to pressure detection in a diaphragm 13b of the pressure sensor 13 described later and a portion other than the diaphragm 13b.

On the other hand, as the seal member 8, an O-ring, a flat packing, a dedicated packing or the like made of an elastic material can be used. In this case, since the O-ring and the flat packing are easily available, they are advantageous for maintenance. For the forming material of the sealing member 8, particularly for the food industry,
In addition to silicon, ethylene propylene rubber, and polytetrafluoroethylene, Viton and Kalrez, which have high corrosion resistance, and Viton seals coated with polytetrafluoroethylene can be used. For general industry, N
BR is also effective.

On the other hand, the pressure detecting unit 5 has a pressure detecting surface 6 which is attached to and detached from the unit mounting portion 3 and faces the pressure acting space 4 on the end face Fs. Specifically, a pressure sensor 13 having the pressure detection surface 6, a casing portion 14 fixed to the pressure sensor 13 and forming a closed space Si facing the reference pressure application surface of the pressure sensor 13, a closed space Si
Is provided with a communication member 15 that communicates with the reference pressure space (atmosphere). The casing part 14 is a cylindrical first casing part 1.
4a and the cylindrical second casing portion 14b are connected by brazing or the like. In this case, the first casing part 1
At the upper end of the outer peripheral surface of 4a, a ring-shaped coupling flange portion 16 is provided.
Is provided outside. The other end surface (the surface opposite to the end surface portion Fs) of the pressure sensor 13 is fixed to the end surface (the lower end surface) of the second casing portion 14b, and the end surface (the upper end surface) of the first casing portion 14a. The gland packing 25 is attached to the opening provided in (2) and closed. In this case, the connection cable 26 is located at the center of the gland packing 25.
And a waterproof gland 27 is screwed onto the upper end of the gland packing 25.

A first electronic circuit 28 is fixed on the upper surface of the pressure sensor 13, and the first casing portion 14a
A second electronic circuit 29 is fixed to the upper end of the second electronic circuit 29. Then, the first electronic circuit 28 is connected to the second electronic circuit 29, and the second electronic circuit 29 is connected to the connection cable 26.
Further, the communication member 15 uses, for example, a hollow tube and is included in the connection cable 26 to thereby communicate the closed space Si with the reference pressure space (atmosphere).

The pressure sensor 13 has a thick substrate 13a and a thin diaphragm 13b. In this case, quartz, sapphire, ceramic, crystalline material, or the like can be used as a material for forming the diaphragm 13b. On the other hand, the thick substrate 13a
Is preferably formed from a material similar to the material forming the diaphragm 13b or a material having a similar expansion coefficient.
This is advantageous in performance and production. One end surface of the diaphragm 13b becomes the pressure detection surface 6, and the other end surface becomes the reference pressure application surface.
Face i. Note that the surface of the pressure detection surface 6 has a measurement medium L
It is also effective to apply a sheet of metal or synthetic resin having high corrosion resistance or to perform a coating process on the sheet.
In this case, Hastelloy, titanium, tantalum, monel, nickel, Inconel, or the like can be used as a metal having high corrosion resistance, and polytetrafluoroethylene or the like can be used as a synthetic resin having high corrosion resistance.

The thick substrate 13a and the diaphragm 13b
It is bonded at regular intervals by glass, active silver brazing, etc., and is kept airtight. Electrodes are provided on the opposing surfaces of the thick substrate 13a and the diaphragm 13b at regular intervals to form at least one capacitor. Thereby, since the capacitance of the capacitor changes due to the deflection of the diaphragm 13b corresponding to the pressure change, the pressure can be detected based on this. The change in the capacitance is converted into an electric signal by the first electronic circuit 28 and the second electronic circuit 29, and applied to a processing device (not shown) via the connection cable 26.

The pressure detection unit 5 ensures waterproofness so that it can be washed. Further, the waterproof gland 27 and the connection cable 26 also ensure airtightness. By the way, in the field of the food industry, it is necessary to measure the liquid level of the measurement medium L with high accuracy, so that a relatively low range of the pressure sensor 13 is required. Therefore, when the closed space Si is made airtight, it becomes difficult to measure the low pressure.
i is communicated with the reference pressure space (atmosphere) via the communication member 15. As a result, it is possible to measure the pressure difference from the atmosphere and to measure the low pressure with high accuracy. The pressure sensor 13
Alternatively, a pressure sensor based on another principle using a resistance wire strain gauge may be used.

On the other hand, the fixing device 9 is a fixing device 18 for simultaneously sandwiching and fixing the connecting flange portion 16 provided on the pressure detecting unit 5 and the connecting flange portion 17 provided on the unit mounting portion 3.
Is used. The fixing device 18 has a pair of holding portions 31 and 32 formed in a semicircular shape, and each holding portion 31 and 32 has a V-shaped cross section. One ends of the holding portions 31 and 32 are rotatably connected by a link portion 33, and a U-shaped latch portion 36 is rotatably attached to the other end of the one holding portion 31. A tightening screw 37 is screwed into the center of the latch portion 36. As a result, the tightening screw 37 is loosened, and the latch 36
Is rotated, the locking portion 32s provided at the other end of the other holding portion 32 can be disengaged, and the locking portion 32s is put into the latch portion 36, and the tightening screw 37 is tightened. The other ends of the holding portions 31 and 32 can be connected. Therefore, if the coupling flange 16 and the coupling flange 17 are sandwiched by the clamping parts 31 and 32 and the other end of the clamping parts 31 and 32 is connected and the fastening screw 37 is tightened, the coupling flange 16 and the coupling flange 17 And the cross-section of the holding portions 31 and 32 is V-shaped, so that as the fastening screw 37 is tightened, the press-contact force between the connecting flange portion 16 and the connecting flange portion 17 can be increased. For this reason, it is desirable that the upper surface of the coupling flange 16 and the lower surface of the coupling flange 17 are formed as inclined surfaces.

Next, a method of assembling the pressure detecting device 1 according to the present embodiment will be described with reference to the drawings.

First, as shown in FIG. 1, the mounting flange portion 22 of the unit mounting portion 3 is formed in an opening formed at a predetermined mounting portion Xc in the storage portion 2 (piping, tank, etc.) in which the measurement medium L is stored. It is attached to Xco by welding, brazing, soldering, bonding, screwing via a sealing material, or the like.

On the other hand, when the pressure detecting unit 5 is mounted on the unit mounting portion 3, the seal member 8 is set on the seal member holding portion 7 of the unit mounting portion 3, and thereafter, the pressure detecting unit 5 is The unit is inserted into the holder unit 21 of the unit mounting unit 3 from the pressure detection surface 6 side. As a result, as shown in FIG. 3, the seal member 8 abuts on the non-pressure detecting surface Fn of the end face Fs of the pressure detecting unit 5, that is, in the vicinity of the outer peripheral side of the end face Fs. The flange portion 17 is in a state of being adjacent.

Next, as shown by the imaginary line in FIG. 2, the fixing device 18 is brought into a state where the locking portion 32s of the other holding portion 32 is detached from the latch portion 36, and the holding portions 31 and 32
As a result, the coupling flange portion 16 and the coupling flange portion 17 are sandwiched, and the locking portion 32s of the other clamping portion 32 is inserted into the latch portion 36, and the fastening screw 37 is tightened. This allows
The other ends of the holding portions 31 and 32 are connected to each other, and the connection flange portion 16 and the connection flange portion 17 can be connected. The pressure detection unit 5 is fixed to the unit mounting portion 3. As described above, the pressure detecting unit 5 can be easily mounted on the unit mounting portion 3 and the pressure detecting unit 5 can be easily detached from the unit mounting portion 3 by performing the reverse procedure. Therefore, the pressure detection unit 5 and the sealing member 8
Can be easily cleaned and new parts can be replaced.

FIG. 5 shows a modified example of the seal member 8. The seal member 8 according to the modified example is such that instead of providing the above-described restricting wall portion 11, the restricting piece portion 1 which is locked to the seal member 8 by the pressure detecting unit 5 (or the unit mounting portion 3).
2 are integrally formed. Thereby, the position of the seal member 8 is regulated, and the same effect as in the case where the regulating wall 11 is provided can be obtained.

FIG. 6 shows a modified embodiment of the pressure detecting device 1. In the modified embodiment, a screw hole portion Xcn having a female screw on the inner peripheral surface is formed in a predetermined attachment portion Xc in the housing portion 2 instead of the above-described opening portion Xco, and the screw hole portion Xcn is formed. The unit mounting part 3 to be mounted is used. Therefore, the unit mounting portion 3 is provided with the screw hole portion Xcn.
Bolted portion 61 screwed to the shaft, and a cylindrical holder portion 62
A ring-shaped seal having a bottom surface 63 formed between the bottom of the holder 62 and the upper end of the bolted portion 61, and a regulating wall 11 at the top (center side) on the top surface of the bottom 63. The member holding portion 7 is formed. Further, a hole-shaped pressure action space 4 is formed at the center of the bolt connection portion 61, and this pressure action space 4 communicates the lower portion of the bolt connection portion 61 with the inside of the holder portion 62. On the other hand, a male screw portion 64 is formed on the outer peripheral surface of the holder portion 62 instead of the coupling flange portion 17 described above. Unit mounting part 3 shown in FIGS. 1 and 6
Although they are different in the form, they are the same in that they are attached to a predetermined attachment site Xc in the accommodating section 2 in which the measurement medium L is accommodated, and that they have a pressure action space 4.

On the other hand, the pressure detecting unit 5 is configured in the same manner as the pressure detecting unit 5 shown in FIG. 1, except that the above-mentioned connecting flange 16 is not provided and the form of the parts used in the details is different. Further, a cylindrical fixing ring 19 is used as the fixing tool 9. The fixing ring 19 has, at the upper end, a locking flange portion 65 that locks to the upper end of the pressure detection unit 5, and forms a female screw portion 66 that is screwed into the male screw portion 64 at the lower end of the inner peripheral surface. In addition, the sealing member 8
Is the same as the seal member 8 shown in FIG. Therefore, the use of the seal member 8 according to the modification shown in FIG.
It can be applied to the modified embodiment shown in FIG. Other configurations are basically the same as those of the embodiment shown in FIG. 2, and the same reference numerals are given to the same portions as FIG. 1 in FIG. 6 to clarify the configuration.

Therefore, when assembling the pressure detecting device 1 shown in FIG.
1 is screwed into the screw hole portion Xcn of the housing portion 2. When the pressure detecting unit 5 is mounted on the unit mounting portion 3, the seal member 8 is set on the seal member holding portion 7 of the unit mounting portion 3, and the pressure detecting unit 5 is moved from the pressure detecting surface 6 side. It is inserted into the holder part 62 of the unit mounting part 3. Next, the fixing ring 19 through which the connection cable 26 passes through the inner space is put on the pressure detecting unit 5 from above, and the female screw portion 66 is screwed to the male screw portion 64 of the unit mounting portion 3. Thereby, the locking flange 65 is locked to the upper end of the pressure detecting unit 5, and the pressure detecting unit 5 is fixed to the unit mounting portion 3. Also in such a modified embodiment, the attachment and detachment of the pressure detecting unit 5 and the unit mounting portion 3 can be easily performed.

As described above, according to the pressure detecting device 1 according to the present embodiment (modified embodiment), the space between the pressure detecting unit 5 and the unit mounting portion 3 comes into contact with the non-pressure detecting surface 6n of the pressure detecting unit 5. Since the device is hermetically sealed by a single seal member 8, the entire device can be reduced in size and size. Further, a regulating wall portion 11 for regulating the position of the sealing member 8 is provided at the tip of the sealing member holding portion 7, or
Since the regulating piece 12 which is locked to the pressure detecting unit 5 or the unit attaching section 3 and whose position is regulated is provided, the sealing member 8 is provided.
Is maintained at a fixed position irrespective of the pressure state, and both positive pressure and negative pressure can be measured stably with high accuracy. In addition, while ensuring the waterproofness (airtightness) of the pressure detection unit 5, the communicating member 15 connects the closed space Si and the reference pressure space (atmosphere).
, The measurement of the differential pressure from the atmosphere becomes possible, and the low pressure can be measured with high accuracy. Therefore, it is particularly suitable for use in the food industry where a relatively low range is required for the pressure sensor 13.

Although the embodiment (modified embodiment) has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, used parts, forming material, quantity, etc. It can be arbitrarily changed, added, or deleted without departing from the gist of the present invention. For example, the concept of “pressure” used in the present invention includes “differential pressure”. Although the reference pressure space has been described as the atmosphere, a separate configuration for supplying a reference pressure of a predetermined size may be used.

[0032]

As described above, according to the present invention, there is provided a unit mounting part which is mounted on a predetermined mounting part of a storage part for storing a measurement medium and has a pressure acting space, and which is detachably mounted on the unit mounting part and has an end face. A pressure detecting unit having a pressure detecting surface facing the pressure acting space in the pressure sensing unit, wherein a seal member sandwiching portion facing the pressure acting space from the unit mounting portion, and between the seal member sandwiching portion and the end face portion. And a fixing member for fixing the pressure detecting unit to the unit mounting portion with the seal member interposed therebetween, the following remarkable effects are obtained.

(1) The device is used to seal the space between the pressure detecting unit and the unit mounting portion with a single sealing member, preferably a single sealing member that abuts against the non-pressure detecting surface at the end face of the pressure detecting unit. The overall size and size can be reduced.

(2) According to a preferred embodiment, a regulating wall for regulating the position of the seal member is provided at the tip of the seal member holding portion, or the seal member is engaged with a pressure detecting unit or a unit mounting portion. By providing the restricting piece for restricting the position, the seal member is held at a fixed position regardless of the pressure state, so that both the positive pressure and the negative pressure can be measured with high accuracy and stability.

(3) According to the preferred embodiment, the low pressure can be measured with high accuracy if the closed space and the reference pressure space are communicated by the communication member while ensuring the waterproofness (airtightness) of the pressure detection unit. Therefore, it is particularly suitable for use in the food industry where a relatively low pressure sensor range is required.

[Brief description of the drawings]

FIG. 1 is a front view including a partial cross section showing components of a pressure detecting device according to a preferred embodiment of the present invention;

FIG. 2 is a plan view of the pressure detecting device,

FIG. 3 is a cross-sectional front view of the pressure detecting device (cross-section taken along line AA in FIG. 2);

FIG. 4 is an enlarged view of a sealing member sandwiching portion and a periphery of the pressure detecting device,

FIG. 5 is an enlarged view of a seal member and its surroundings according to a modification of the pressure detection device.

FIG. 6 is a front view including a partial cross section showing components of a pressure detecting device according to a modified embodiment of the present invention,

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure detecting device 2 housing portion 3 unit mounting portion 4 pressure acting space 5 pressure detecting unit 6 pressure detecting surface 7 seal member sandwiching portion 8 seal member 9 fixing tool 11 regulating wall portion 12 regulating piece portion 13 pressure sensor 14 casing portion 15 communication Member 16 Coupling flange portion 17 Coupling flange portion 18 Fixing device 19 Fixing ring L Measurement medium Xc Attachment site Fs End face Fn Non-pressure detecting surface Si Closed space

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA39 BB20 CC02 DD09 EE12 EE25 FF11 GG11 HH03

Claims (7)

[Claims] 1. A unit mounting part which is attached to a predetermined mounting part of a housing part in which a measurement medium is stored and has a pressure action space, is detachably attached to the unit mounting part, and faces the pressure action space at an end face part. A pressure detecting device comprising a pressure detecting unit having a pressure detecting surface, wherein a seal member holding portion facing the pressure action space from the unit mounting portion, and a seal interposed between the seal member holding portion and the end surface portion. A pressure detecting device, comprising: a member; and a fixing member which can fix the pressure detecting unit to the unit mounting portion with the seal member interposed therebetween. 2. The pressure detecting device according to claim 1, wherein the seal member is brought into contact with a non-pressure detecting surface of the end face portion. 3. The pressure detecting device according to claim 1, wherein the seal member holding portion has a regulating wall at a tip end for regulating the position of the seal member. 4. The pressure detecting device according to claim 1, wherein the seal member has a restricting piece that is locked to the pressure detecting unit or the unit mounting portion to restrict the position. 5. The pressure detection unit, comprising: a pressure sensor having the pressure detection surface; a casing fixed to the pressure sensor and forming a closed space facing a reference pressure application surface of the pressure sensor; A communication member for communicating the space with the reference pressure space is provided.
The pressure detection device as described in the above. 6. The fixing device according to claim 1, wherein the fixing device is a fixing device for simultaneously sandwiching and fixing a connecting flange provided on the pressure detecting unit and a connecting flange provided on the unit mounting portion. Pressure detector. 7. The pressure detecting device according to claim 1, wherein the fixing member is a cylindrical fixing ring which is locked to the pressure detecting unit and screwed to the unit mounting portion.