JPH05107132A - Sanitary pressure intensifier - Google Patents

Abstract

PURPOSE:To obtain a pressure intensifier which can meet various severe conditions, such as frequent execution of overhauls, etc., imposed to the intensifier when the intensifier is applied to a food manufacturing machine and can maintain high measurement accuracy by suppressing the deformation of a pressure receiving diaphragm at the time of assembling and reassembling the intensifier. CONSTITUTION:This pressure intensifier 20 has an internal surface which is formed to an easily washable form and, in order to conveniently wash the intensifier 20 which is to be washed frequently, can be divided into two parts, i.e., a lead-in member 21 and a strain starting body 22, which can be airtightly joined to each other with a gasket 24 having a ring-like projecting section in between by means of an annular clamping member 30. Especially, a diaphragm 23 which is deformed in response to an applied pressure is provided at the midportion of cylindrical rigid body part of, the body 22 namely, on a stress neutral surface. A pressure medium from an object to be measured is introduced to the lead-in through path 21b of the member 21 and impressed upon the diaphragm 23. As a result, the diaphragm 23 is deformed and the resistance value of a strain gauge 27 is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a liquid or gas (collectively referred to as "fluid" hereinafter) to a pressure receiving diaphragm as a pressure medium to deform the pressure receiving diaphragm and detect the amount of deformation of the pressure receiving diaphragm with a strain gauge. By doing so, the present invention relates to a pressure converter that outputs an electric signal corresponding to the pressure applied from a pressure detection target, and in particular, a pressure converter with a sanitary property that can be applied to a mechanical device used in the manufacturing process of food and medicine. It is about.

[0002]

2. Description of the Related Art A conventional pressure transducer is basically constructed to have a structure as shown in FIG. In FIG. 8, reference numeral 1 denotes an introduction member of a general pressure transducer, which is used to bond and fix the pressure transducer to various devices, containers, pipes, etc., which are pressure sensing objects, and from the pressure sensing object. Is introduced as a member for introducing the fluid into the pressure transducer.

The introduction member 1 has an introduction through hole 1a for forming a fluid introduction passage in the central portion thereof, and a left end portion (on the drawing) is a screw portion 1b having an outer peripheral surface threaded.
The right end portion is formed as a flange-shaped large diameter portion 1c.

Reference numeral 2 denotes an outer cylindrical member which is fitted at its left end portion to the large diameter portion 1c of the introducing member 1 so as to project in a tubular shape toward the introducing member 1 side, and an inner intermediate portion of this projecting portion. It is provided so as to have a pressure receiving diaphragm 2a having a structure for closing the hollow portion formed in the. In this case, the left side surface of the pressure receiving diaphragm 2a serves as a pressure receiving surface, and the right side surface described later serves as an attachment surface of the strain gauge 3.

The outer cylinder member 2 is a large diameter portion 1 of the introduction member 1.
After the introducing member 1 is fitted in such a manner that the rising surface 1d of c is substantially flush with the left end surface of the outer tubular member 2, the introducing member 1 is welded at the outer peripheral portion of the rising surface 1d. It is configured to be fixed in an airtight manner to.

Reference numeral 3 is a strain gauge attached to the attachment surface of the pressure receiving diaphragm 2a with an adhesive or the like. Four
Is fixed to the right end of the outer cylinder member 2 and the strain gauge 3
In some cases, a circuit is formed by a compensation resistor on the relay board electrically connected to the board.

Reference numeral 5 denotes a hollow case whose left end is fixed to the outer periphery of the right end of the outer tubular member 2 by welding or the like, and 6 is a waterproof connector whose left end is fitted in the right end of the case 5. It is configured to be electrically connected to the relay board 4 so that the converted output (electrical signal) of the strain gauge 3 can be extracted to the outside. Reference numeral 7 is a fixture for fixing the waterproof connector 6 to the case 5, and 8 is an O-ring for sealing the joint between the case 5 and the waterproof connector 6.

In the pressure transducer having such a structure, the pressure of the fluid guided from the pressure detection target through the introduction member 1 is applied to the pressure receiving diaphragm 2a to deform it and attach it to the pressure receiving diaphragm 2a. The strain gauge 3 is configured to detect the strain associated with this deformation and obtain an electric signal output corresponding to the applied pressure.

In order to attach the pressure transducer thus constructed to the pressure detection object, as shown in FIG.
A gasket 10 is provided between the outer wall 9 or the pressure outlet pipe of the pressure detection target (container) and the rising surface 1d of the introducing member 1 and the left end surface of the outer tubular member 2 which is substantially flush with the rising surface 1d. It is usual that the threaded portion 1b of the introduction member 1 is screwed into a screw hole threaded in the outer wall 9 or the like, and the threaded portion 1b is fastened and fixed.

[0010]

However, since a metal material such as a copper alloy is usually used for the gasket 10, a considerable tightening torque is required to obtain a sufficient sealing effect when tightening and fixing. ..

Therefore, when the pressure transducer is screwed into the screw hole of the outer wall 9 of the pressure detection object, a bending moment M as exaggeratedly shown in FIG. The bending moment M is as shown in FIG.
Is deformed and also the pressure receiving diaphragm 2a is deformed, which causes a big problem of zero-point fluctuation of the converted output of the pressure converter.

That is, when fluid pressure is applied to the pressure receiving diaphragm 2a through the introduction through hole 1a of the introducing member 1 in the state where the phenomenon of the zero point variation occurs, the pressure receiving diaphragm 2a is not deformed by the above-mentioned tightening. Compared with the case, the sensitivity of the conversion system changes, and the pressure receiving diaphragm 2a
As a result, the linearity of the pressure-electrical output conversion characteristic of 1 is greatly deteriorated.

By the way, the large diameter portion 1c of the introduction member 1 fitted and fixed to the outer cylinder member 2 prevents the outer cylinder member 2 from being deformed to a certain extent or more due to its rigidity when the pressure transducer is clamped and fixed. Work like.

The effect in this case becomes larger as the gap G between the introducing member 1 and the outer cylinder member 2 becomes smaller.
Naturally, it is desirable to make the gap G of the fitting portion as small as possible, but the gap G cannot be completely reduced to zero because of the limit of the fitting portion.

Further, since it is also demanded to reduce the weight of the pressure converter, in order to satisfy this demand, as shown in FIG. 10, the large diameter portion 1c of the introducing member 1 is provided with a length (flange). If the wall thickness) is reduced, the function of preventing the deformation of the outer cylinder member 2 described above becomes weaker, and the pressure receiving diaphragm 2a is more easily deformed.

Therefore, in the prior art, the above-mentioned pressure-
In order to suppress the phenomenon that the linearity of the electric output conversion characteristic is largely broken by the rigidity of the large diameter portion 1c of the introducing member 1,
I was in a state where I could hardly expect it.

If a pressure transducer having such a problem is used in a mechanical device used in a chemical manufacturing process or a food manufacturing process (hereinafter, these are collectively referred to as "food mechanical device"), another The problem arises.

That is, since the food machine device comes into contact with food that enters the human mouth, it is necessary to give sufficient consideration to the sanitary property. Therefore, various sensors used in the food machine device also need to be machined. As with the device, it is necessary to give sufficient consideration to sanitary properties.

In particular, it is necessary to consider the sanitary material and the sanitary structure for the sensor and its mounting portion which directly contact the medicine or food. In this case, there are the following conditions as points for giving the sanitary property.

(A) Product safety must be maintained. That is, the material of the member that comes into contact with food is non-toxic and hygienic, there is no risk of harmful substances leaking from inside the sensor due to cracks, corrosion, etc., and excellent corrosion resistance, heat resistance, and wear resistance.

(B) Good cleaning performance. In other words, it should be able to withstand CIP cleaning and sterilization by hot water / steam, with a structure that allows complete cleaning (structure that does not retain fluid etc.) and is smooth and polished. In particular, there should be no screw threads that touch the product, and all inner corners should be 3.28.
Provide a roundness (curved surface) of mm or more, and the groove for gasket has a depth of about 6.4 mm or less or a width of about 6.4 mm or more.

(C) Good decomposition performance. In other words, all the parts to be installed can be easily installed and removed, and the area around the installation part is smooth and has no dead zone.

(D) Easy inspection. In other words, the design should be such that when the attached parts are removed, both the inside and outside surfaces can be inspected. Therefore, in order to design a pressure converter having a hygienic property, it is necessary to satisfy such a structural condition.

The present invention has been made in view of the above circumstances, and satisfies various severe conditions for use in chemical machinery and food machinery, and also suppresses the initial deformation phenomenon of the pressure receiving diaphragm. It is an object of the present invention to provide a pressure transducer with a new hygienic property that can maintain high measurement accuracy.

[0025]

In order to achieve the above object, the invention according to claim 1 applies a fluid from a pressure sensing object as a pressure medium to a pressure receiving diaphragm to deform it, and In a pressure transducer that obtains an electric signal corresponding to the applied pressure from the pressure detection target by detecting the deformation amount of the pressure receiving diaphragm with a strain gauge,
One rigid member constituting an introduction passage forming member forming an introduction passage for guiding a fluid from the pressure detection target to the pressure receiving diaphragm, the end portion of which directly or indirectly to the pressure detection target. A hollow first introduction member to be connected, a seal member formed in an annular shape and abutting against an end surface of the first introduction member on the non-pressure detection target side, and an introduction passage forming member forming the introduction passage. Which is the other rigid member constituting the second introduction member which is joined to the end surface of the first introduction member on the non-pressure detection target side through the seal member so as to be able to come into contact with and separate from the second introduction member. It is possible to detachably join the first introducing member and the second introducing member at a position not to be formed, and by this joining operation, the sealing member can be continuously compressed in its thickness direction. Union A step, and is formed integrally or integrally with the second introducing member in a state of blocking the introducing passage inside the second introducing member, and the second introducing member is the first introducing member by the coupling means. A stress-neutral structure which is not affected by compressive stress and tensile stress generated in the inner wall portion of the rigid body portion of the second introduction member due to the bending moment generated in the joint portion of the second introduction member when joined to the member. And a strain gauge attached to a surface of the pressure receiving diaphragm on the non-pressure detection target side of the pressure receiving diaphragm.

According to the second aspect of the invention, the fluid from the pressure detection target is applied as a pressure medium to the pressure receiving diaphragm to deform it, and the deformation amount of the pressure receiving diaphragm is detected by a strain gauge. A pressure converter that outputs an electric signal corresponding to an applied pressure from the pressure detection target object, and constitutes an introduction path forming member that forms an introduction path for guiding the fluid from the pressure detection target object to the pressure receiving diaphragm. One rigid member, a hollow first introduction member whose end is directly or indirectly connected to the pressure detection target, and a non-pressure detection target of the first introduction member which is formed in an annular shape A seal member removably attached to the end face on the side of the other end, and the other rigid member constituting the introduction passage forming member forming the introduction passage, the seal member being interposed And a second introducing member that is detachably connected to the end surface of the first introducing member on the non-pressure detection target side, and the first introducing member and the second introducing member at a position that does not directly contact the fluid. Is detachably coupled, and the coupling means is configured to keep the sealing member compressed in the thickness direction by this coupling operation, and the introduction passage inside the second introduction member. Is formed integrally or integrally with the second introducing member in a state of blocking, and when the second introducing member is joined to the first introducing member by the joining means, The pressure receiving diaphragm provided so as to be located on a stress neutral surface that is not affected by compressive stress and tensile stress generated in the inner wall portion of the rigid body portion of the second introducing member due to the bending moment generated in the joint portion. And a force transmission member provided in the central portion of the surface of the pressure receiving diaphragm on the non-pressure detection target side, the end portion of which is a thin wall formed integrally or integrally with the second introduction member. A strain member,
It is characterized by comprising the strain gauge attached on the strain-flexing member.

[0027]

With the sanitary pressure converter configured as described above, at least the introduction passage forming member forming the introduction passage for guiding the fluid from the pressure detection object to the pressure receiving diaphragm can be attached and detached. It is composed of two rigid members to enable disassembly and cleaning.

Further, a pressure-receiving diaphragm is provided inside the rigid member located on the side of the non-pressure detection object so as to block the introduction passage, and the end portions of the respective rigid members facing each other through an appropriate sealing member. A flange portion is formed on the base plate, and the seal member is compressively sandwiched between the flange portions so that the pressure medium applied from the introduction passage is applied to the diaphragm without leaking. ..

Further, by using an appropriate mechanical coupling means, the two flange portions are coupled to each other in such a state that the seal member can be continuously compressed in its thickness direction at a portion which does not come into direct contact with the fluid. The connecting member, which is difficult to clean, is not exposed to the fluid.

At this time, the inner wall of the rigid body portion of the second introducing member is caused by the bending moment generated in the flange portion (the end portion on the side of the pressure detection object) of the rigid body member having the pressure receiving diaphragm in response to this coupling operation. The position of the stress-neutral surface that is not affected by the compressive stress and tensile stress generated in the part is determined, and the pressure-receiving diaphragm is provided so as to coincide with this surface position. It's suppressed.

A strain gauge is attached to the surface of the pressure receiving diaphragm on the side of the non-pressure detection object, and even when the two rigid members are connected by the connecting means, unnecessary initial deformation of the pressure receiving diaphragm occurs. In a state that does not occur,
The strain gauge is adapted to obtain a strain detection signal corresponding to the amount of deformation of the pressure receiving diaphragm that occurs with the pressure application.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pressure converter having a sanitary property according to the present invention will be described in detail based on illustrated embodiments. Figure 1
FIG. 3 is a cross-sectional view showing the configuration of an embodiment of a pressure converter having sanitary properties according to the present invention.

In the figure, reference numeral 20 denotes a hygienic pressure transducer of the present invention, which is basically a first introduction fixed to a pressure detection object (not shown) by an appropriate detachable coupling means. Introduction member 21 as a member and this introduction member 21
And a thickness H formed inside the strain-flexing main body 22 as a second introducing member that is combined with the strain-deflecting main body 22 in a manner opposing to each other.
The pressure-receiving diaphragm 23, the ring-shaped convex gasket 24 interposed between the introducing member 21 and the strain-flexing body 22, and the introducing member 21 for fitting and abutting the convex portion of the ring-shaped convex gasket 24. The first ring groove 25 provided in the first ring groove 25, the second ring groove 26 provided in the strain-flexing main body 22 so as to face the first ring groove 25, and the right end surface side (non-pressure receiving surface) of the pressure receiving diaphragm 23 described above. It is composed of a strain gauge 27 attached to the side) and an annular tightening member 30 that simultaneously tightens and joins the introducing member 21 and the strain-flexing main body 22 from the outer peripheral direction.

The introducing member 21 is a rigid member corresponding to the first introducing member described in the claims, and has a long cylindrical portion whose left side portion communicates directly or indirectly with the pressure detection target ( For example, it is configured as 100 mm) 21a, and its hollow portion is configured to be used as an introduction through hole (introduction passage) 21b for introducing a fluid that is a pressure medium.

The right side portion of the introducing member 21 is formed as a flange portion 21c having a diameter much larger than that of the cylindrical portion 21a, and the outer surface on the pressure detection target side (left side in FIG. 1) has an appropriate taper angle. It is formed as a male taper surface 21d having. Further, the right end surface of the introducing member 21 including the right end surface of the flange portion 21c is connected to the joint surface 21 facing the strain-flexing body 22 via the gasket 24 having the ring-shaped convex portion.
It is formed as e.

In this case, the introduction member 21 is made of stainless steel so as to have the above-mentioned sanitary property, and the inner peripheral surface of the introduction through hole 21b and the coupling surface 21e are smooth surfaces. Will be finished.

On the other hand, the strain-flexing main body 22 is a rigid member corresponding to the second introducing member described in the claims, and has a large diameter whose left side portion is symmetrical with the flange portion 21c of the introducing member 21. Is formed as a flange portion 22a of the introduction member 21, the outer surface on the right side thereof is formed as a male taper surface 22b having a symmetric taper angle with the male taper surface 21d of the introduction member 21, and the left end surface thereof is a gasket with a ring-shaped protrusion A coupling surface 22c facing the introduction member 21 via 24
Is formed as.

The right side portion of the strain-flexing body 22 is formed as a stepped cylindrical portion 22d having a smaller diameter than the flange portion 22a, and the outer peripheral surface thereof has, for example, the case 5 described in the section "Prior Art". An appropriate screw portion 22e for screwingly attaching an electric member (not shown) corresponding to the above is formed.

Further, the pressure receiving diaphragm 23 is integrally formed at the inner intermediate portion of the strain-flexing main body 22 as described above, and the formation position of the pressure receiving diaphragm 23 will be described in detail later.

Further, on the left side portion (portion in the direction of the pressure detection target) of the pressure receiving diaphragm 23, the introducing member 21 is provided via the hollow portion 24a of the ring-shaped convex gasket 24.
Is formed with a leftward recess (a part of the introduction passage) 22f communicating with the introduction through hole 21b of the pressure receiving diaphragm 23.
On the right side portion (portion on the right side of the pressure receiving diaphragm 23), for example, a rightward concave portion with a mounting step surface 22g for mounting a member (not shown) corresponding to the relay board 4 described in the section "Prior Art". 22h is formed.

In order to satisfy the above-mentioned sanitary property, stainless steel is used for the material of the strain-flexing main body 22 and the pressure receiving diaphragm 23, and the connecting surface 22 is used.
c, the inner peripheral surface of the leftward recess 22f and the left side surface of the pressure receiving diaphragm 23 are both finished to be smooth surfaces, and
A roundness (for example, a radius of 3.3 mm) that satisfies the above-mentioned sanitary property is formed at the inner corner of the left-side concave portion 22f.

The above-mentioned ring-shaped convex gasket 24
Is a member corresponding to the sealing member described in the claims, and is configured as a ring-shaped plate member as a whole by a copper alloy material, for example, and the inner diameter of the hollow portion 24a is
It is set to be substantially the same as the inner diameter of the introduction through hole 21b of the introduction member 21.

As shown in a partially enlarged view in FIG. 2, in the vicinity of the outer circumferences of the left and right end faces thereof, a convex portion 24b having a semicircular cross section for enhancing the sealing effect is provided with a ring-shaped convex portion. The gasket 24 is formed in an annular shape over the entire circumference thereof. In this case, the height of each convex portion 24b is set to about 6.4 mm or less so as to satisfy the above-mentioned sanitary property.

The above-mentioned first ring groove 25 is provided in the introducing member 21.
It is provided in a region near the outer circumference of the coupling surface 21e of the introducing member 21 so that the left convex portion 24b of the ring-shaped convex gasket 24 can be embedded when the strain main body 22 and the strain-resisting body 22 are coupled.

Similarly, the second ring groove 26 is provided in a region near the outer periphery of the coupling surface 22c of the strain-flexing body 22 so that the right convex portion 24b of the ring-shaped convex gasket 24 can be embedded.

In this case, in order to satisfy the above-mentioned sanitary property, the material of the gasket 24 with ring-shaped protrusions is
A material with excellent chemical resistance or corrosion resistance, such as silicon resin or Teflon resin, is used, and the depth of the two ring grooves 25, 26 is set to about 6.4 mm or less. become.

Numeral 27 is a strain gauge attached to the non-pressure receiving surface of the pressure receiving diaphragm 23 with, for example, an adhesive, the structure itself is constructed in the same manner as a known one, and its converted output (electric signal) is first of all appropriate. Via an electric member corresponding to the relay board 4 described above by a lead wire (not shown), and further using an appropriate take-out connection line, from this electric member,
For example, it is configured so that it can be connected to an electric output take-out means (not shown) corresponding to the waterproof connector 6 described in the section "Prior Art" and finally drawn out.

By the way, the introducing member 21 and the strain-flexing main body 22 configured as described above are provided with respective flange portions 21c.
1 and 22a with the ring-shaped convex gasket 24 sandwiched therebetween, as shown in FIG. 1. The connecting method in this case is that the flanges 21c and 22a are annularly tightened from the outside by the annular fastening member 30. Are engaged and the annular tightening member 30 is appropriately tightened.

As shown in FIG. 3, the annular tightening member 30 is a composite structural member that surrounds the outer peripheries of both the flange portions 21c and 22a sandwiching the gasket 24 with the ring-shaped convex portion and being joined together. , A plurality of, in this case, three circular arc pieces 31A to 31C, which are annularly connected to each other so as to have a slight gap or interference between adjacent circular arc pieces. ing.

In this case, three arc pieces 31A to 31C
Is, for example, as shown in FIG. 4, between one end of the left arc piece 31A and one end of the middle arc piece 31B, and between the other end of this middle arc piece 31B and the right arc piece 31C. For example, an appropriate link member 32 is provided between one end and the other.
Are connected so that they can rotate relative to each other,
The other end of the arc piece 31A on the left side and the other end of the arc piece 31C on the right side are connected by a tightening operation means 33 including a detachable butterfly bolt 33a and a nut 33b. It will be configured into a structure.

Further, each arc piece 31A to 31C
Is formed as a member having a trapezoidal cross-section recess (groove) 34 as shown in FIG. 1 in its inner portion, and the slopes formed on both sides of the trapezoidal cross-section recess 34 are the male taper of the introduction member 21 described above. A female taper surface 34 that smoothly fits the surface 21d and the male taper surface 22b of the strain-flexing body 22.
formed as a and 34b.

The female taper surfaces (slopes) 34a and 34b
When the tightening operation means 33 is tightened and the three arc pieces 31A to 31C are simultaneously displaced inward by a small amount, the male taper surfaces 21d and 22b of the introducing member 21 and the strain-flexing main body 22 become Due to the sandwiching action (sandwiching action) that is exerted between the connecting member 21e of the introducing member 21 and the strain-flexing body 2
The two connecting surfaces 22c are brought close to each other by a strong force.
Gasket 24 with ring-shaped protrusion between 1e and 22c
Is configured to be strongly compressed.

By the way, the introducing member 21 and the strain-flexing body 2
Each of the male taper surfaces 21d and 22b of FIG.
When the gasket 24 with the ring-shaped convex portion is compressed by sandwiching and pressing the two female tapered surfaces 34a and 34b of No. 4, when the gasket 24 is present,
A female taper surface 34b on the outer peripheral portion of the flange portion 22a of
The pressing force to the left by

Therefore, when viewed macroscopically, the strain main body 2
A bending moment is generated in the flange portion 22a of No. 2 and the outer peripheral portion of the flange portion 22a bends leftward and the inner portion bends rightward so that the joint surface 22c of the flange portion 22a is deformed into an arc shape as shown in FIG. become.

At this time, the coupling surface 22 of the flange portion 22a
On c, internal stress (compressive stress) is generated toward the center of the strain-flexing body 22, and on the end surface 22d ′ of the tubular portion 22d,
On the contrary, an internal stress (tensile stress) is generated in the outward direction of the strain-flexing main body 22.

Therefore, as shown in the comparative example of FIG. 12, if the pressure receiving diaphragm 23 'is provided at a position which coincides with the left end face 22c' of the strain-flexing body 22 ',
When the strain-flexing main body 22 'is coupled to the introducing member 21 using the annular tightening member 30, the coupling surface 22c' and the pressure-receiving diaphragm 23 'of the strain-flexing main body 22' bend to a state as shown in FIG. At this time, the pressure receiving diaphragm 23 '
14 causes a compressive stress as shown in FIG. 14, that is, a compressive stress having a characteristic of increasing as a quadratic curve as the thickness H of the pressure receiving diaphragm 23 'becomes thinner.

Therefore, the strain gauge 27 adjusted to obtain a proper initial output is installed in the pressure receiving diaphragm 2
When the strain-flexing main body 22 'is joined to the introducing member 21 by utilizing the annular tightening member 30 after being attached to the right end face of 3', the initial strain gauge 27 due to the bending moment of the joint portion generated at the time of joining. This results in a large change in the output and a deterioration in the linearity of the pressure-electricity conversion characteristics, which significantly deteriorates the measurement accuracy.

Further, assuming that the strain-flexing main body 22 'is introduced into the introducing member 2
Even if the strain gauge 27 is attached to the left end surface of the pressure receiving diaphragm 23 'after being coupled to 1, once analyzed for cleaning, the initial output of the strain gauge 27 will be due to the compressive stress generated during reassembly. There is an inconvenience that it greatly changes with respect to the value at the time of manufacture. Moreover, since this amount of change changes according to the degree of tightening of the annular tightening member 30 at that time, even if this method is used, the measurement accuracy is significantly deteriorated.

By the way, when the introducing member 21 and the strain-flexing main body 22 are joined together by using the annular fastening member 30, the inner wall portion of the joining surface 22c (joint portion) of the flange portion 22a is
As described above, the compressive stress is generated and the tensile stress is generated in the inner wall portion of the tubular portion 22d.

In this case, at the intermediate position of the inner wall between the coupling surface 22c and the tubular portion 22d, there is a surface where the internal stress is reversed from the compressive stress to the tensile stress, that is, the surface which becomes the stress neutral surface. It will be.

The position of the stress neutral surface will vary depending on the shape, length, diameter and wall thickness of each portion of the strain-flexing main body 22 including the cylindrical portion 22d. Right position (attachment position of strain gauge 27)
Is set at a position that coincides with the stress neutral surface, even when the introducing member 21 and the strain-flexing main body 22 are connected by using the annular tightening member 30, the pressure receiving diaphragm 23
Therefore, substantially no compressive stress occurs. Alternatively,
Even if it occurs, it should have an extremely small compressive stress as shown by point P in FIG. 14, for example.

With this in mind, the present invention is constructed so that the position of the pressure receiving diaphragm 23 is placed on the stress neutral surface of the strain-flexing main body 22.

The problem of this stress deformation is that the introduction member 2
Although it occurs in the case of the flange portion 21c of No. 1,
Since there is no functionally delicate part like the pressure receiving diaphragm 23 on the introducing member 21 side, it is not necessary to consider this problem on the introducing member 21 side.

In the illustrated embodiment constructed in this way, a sufficiently cleaned introducing member 21, strain-flexing body 22, gasket 24 with ring-shaped convex portion and annular tightening member 30 are prepared. First, they are provided on the coupling surface 21e. First ring groove 2
The gasket 24 with the ring-shaped convex portion is attached to the coupling surface 21e of the introducing member 21 while fitting the left-side convex portion 24b into the inside 5.

A predetermined number of strain gauges 27 are attached in advance to a predetermined position on the right end surface of the pressure receiving diaphragm 23 provided on the strain-flexing main body 22, and the mounting step surface 2 is further attached.
The lead wire of the strain gauge 27 is soldered to an electric relay member (not shown) of an appropriate structure attached to 2 g, and the strain gauge 2 is connected by using an appropriate electric connection wire.
It is pre-assembled so that the converted output of 7 can be led to the outside from the electrical relay member.

While fitting the right convex portion 24b of the ring-shaped convex gasket 24 into the second ring groove 26 provided on the joint surface 22c of the strain main body 22, the joint surface 22c of the strain main body 22 is fixed. Ring-shaped convex gasket 24
The strain gauge 27 is pressed against the right side of the
The strain-flexing main body 22 after attachment is attached to the gasket 2 with a ring-shaped convex portion.
It is mounted so as to be opposed to the introduction member 21 via 4.

Then, in this state, the introducing member 21
And, three arc pieces 31A to 31C of the annular tightening member 30 as shown in FIG. 3 are attached to the outer peripheral portions of both the flange portions 21c and 22a of the strain-flexing main body 22, and the three arc pieces 31A to 31C.
Female taper surface 3 of each trapezoidal cross-section recess 34 of 31C
4a, 34b and male taper surfaces 21d, 22b of both flange portions 21c, 22a of the introducing member 21 and the strain-flexing body 22.
Engage and.

Further, by operating the tightening operation means 33, the gap between the three arc pieces 31A to 31C is tightened to displace the annular tightening member 30 inwardly by a small amount, and the two sets of engaged two sets are engaged. Female and male tapered surfaces 34a,
The flange portion 21c of the introducing member 21 and the flange portion 22a of the strain-flexing main body 22 are coupled by utilizing the sandwiching action of 21d and 34b, 22b.

At this time, the flange portion 21 of the introducing member 21
A strong compressive force is generated between c and the flange portion 22a of the strain-flexing main body 22 due to the sandwiching action of the two sets of female and male tapered surfaces.

On the one hand, this strong compressive force is applied to the gasket 24 with the ring-shaped convex portion, and the introduction member 21
A high sealing effect is produced between the coupling surface 21e of the above and the gasket 24 with the ring-shaped convex portion and between the gasket 24 with the ring-shaped convex portion and the coupling surface 22c of the strain-flexing body 22. Then, a bending moment is generated in the joint portion, and the flange portion 22a is bent in an arc shape as exaggeratedly shown in FIG.

However, in the present invention, since the pressure-receiving diaphragm 23, which requires a delicate stability accuracy, is provided in advance on the stress neutral surface of the strain-flexing main body 22, a strong compressive force is applied to the flange of the strain-flexing main body 22. Even if added to the portion 22a, no harmful internal stress is generated in the pressure receiving diaphragm 23. That is, the pressure receiving diaphragm 23 is placed in a stress-stable state.

Since this stress-stable state is realized even when the pressure converter 20 having sanitary properties is disassembled and rejoined for cleaning, for example, the pressure having sanitary properties according to the present invention is used. In the converter 20, the strain gauge 2
The converted output of No. 7 is always kept with high accuracy. That is, it is possible to obtain an effect that high measurement accuracy can be stably obtained.

Moreover, the four main members constituting the pressure converter 20, that is, the introducing member 21, the strain-flexing main body 22, the gasket 24 with the ring-shaped convex portion, and the annular tightening member 30 can be easily disassembled and re-joined. Since it is assembled as described above, the internal inspection and cleaning of the pressure transducer 20 can be easily performed, and further, since it is not necessary to use a screw connection at a portion which comes into direct contact with a fluid, a sanitary property can be obtained. It can be sufficiently used as a pressure transducer having a strictly required sanitary property.

Although one embodiment has been described above, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

For example, in the illustrated embodiment, the introduction member 21 and the strain-flexing body 22 are continuously formed over the entire outer peripheral area of both flange portions 21c and 22a by using the annular tightening member 30 formed of three arc pieces. However, if a substantially sufficient coupling effect is obtained, another type or structure of the fastening member, for example, as shown in FIG. A tightening member composed of a C-shaped tightening ring 40 to which a necessary tightening margin (tightening force) is applied in advance, and a tightening member including a tightening bolt 51 and a tightening nut 52 as shown in FIG. 6 are used. Both flanges 21c ・ 2
The 2a may be configured to be partially tightened at several positions.

In the illustrated embodiment, the strain gauge 27
Is arranged on the surface of the pressure receiving diaphragm 23 on the non-pressure detection target side, the force transmission member 61 is provided at the center of the surface of the pressure receiving diaphragm 23 on the non-pressure detection target side, as shown in FIG. In addition to the above, the tip of the force transmitting member (force transmitting rod) 61 is connected to the strain generating member (strain plate) 62 whose end portion is connected to the tubular portion of the strain generating main body, and on its surface. The present invention can also be applied to a pressure transducer (so-called beam-type pressure transducer) configured such that the strain gauge 27 is provided in the.

In the illustrated embodiment, the convex portions 24b are formed on both sides.
Although the ring-shaped convex gasket 24 in which the ridge is formed is used, the presence of the convex portion 24b is not an essential condition of the present invention, and the annular tightening member 30 is used to separate the introducing member 21 and the strain-flexing body 22. The present invention can also be applied to a configuration in which a gasket or a seal member having a structure that causes stress deformation in the flange portion 22a or the coupling surface 22c of the strain-flexing main body 22 when tightened and coupled. Needless to say.

Further, although the convex portions 24b are formed on both surfaces of the ring-shaped convex gasket 24, the convex portions 24b may be formed only on the surface of the strain-flexing main body 22 side.

[0079]

As described above, the sanitary pressure converter according to the present invention is subject to various severe conditions such as frequent disassembly and cleaning for use in chemical machinery, food machinery and the like. Further, it is possible to provide a pressure converter having a new hygienic property that satisfies the above condition and can suppress the deformation phenomenon of the pressure receiving diaphragm at the time of reassembly after disassembly to maintain high measurement accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a basic configuration of an embodiment of a pressure converter having a hygienic property according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing the structure of a gasket with a ring-shaped convex portion used in the pressure converter having the hygienic property of FIG.

FIG. 3 is a plan view showing a schematic configuration of an annular tightening member used in the pressure converter having sanitary properties shown in FIG.

FIG. 4 is a partial plan view showing the structure of a link member for connecting the three arc pieces forming the annular tightening member of FIG. 3 so as to have a certain gap.

5 is a schematic view showing the structure of another type or structure of the tightening member used in the hygienic pressure converter of FIG. 1. FIG.

FIG. 6 is a schematic view showing a structure of a tightening member having a different type or structure from that of FIG.

FIG. 7 is a schematic cross-sectional view when the present invention is applied to a pressure converter having a hygienic property having a configuration different from that shown in FIG.

FIG. 8 is an overall cross-sectional view for explaining the configuration of an example of a conventional pressure converter.

9 is a partial cross-sectional view for explaining a problem of the pressure converter shown in FIG.

FIG. 10 is a partial cross-sectional view for explaining the problem of the pressure converter shown in FIG. 8, similar to FIG.

11 is a stress action explanatory view for explaining a compressive stress and a tensile stress generated in a flange portion of the strain-flexing main body when the introducing member and the strain-flexing main body are coupled using the annular tightening member shown in FIG. Is.

FIG. 12 is a main cross-sectional view showing a configuration of a comparative example in which a pressure receiving diaphragm is provided at a position that coincides with a left end surface of a strain-flexing main body.

13 is a comparative stress action explanatory view for explaining a compressive stress and a tensile stress generated in a comparative example having the configuration shown in FIG.

14 is a correlation diagram for explaining the relationship between the thickness of the pressure receiving diaphragm and the compressive stress in the comparative example having the configuration shown in FIG.

[Explanation of symbols]

 20 Sanitary pressure converter 21 Introducing member 21a Cylindrical part 21b Introductory through hole 21c Flange part 21d Male taper surface 21e Coupling surface 22 Strain main body 22a Flange part 22b Male taper surface 22c Coupling surface 22d Cylindrical part 22d ' End face of tubular part 22e Screw part 22f Leftward recessed part 22g Mounting step face 22h Rightward recessed part 23 Pressure receiving diaphragm 24 Ring-shaped convex gasket 24a Hollow part 24b Convex part 25 First ring groove 26 Second ring groove 27 Strain gauge 30 Ring tightening Member 31A to 31C Arc piece 32 Link member 33 Tightening operation means 34 Trapezoidal cross-section concave part (groove part) 34a, 34b Female taper surface (slope) 40 C character-shaped tightening ring 41, 42 Action point 51 Tightening bolt 52 Tightening nut 61 Force transmission Member 62 Distortion member (Okoshiibitsuban)

Claims (2)

[Claims] 1. A pressure applied from a pressure detection target object by applying a fluid from the pressure detection target object as a pressure medium to a pressure reception diaphragm to deform it and detecting the deformation amount of the pressure detection diaphragm with a strain gauge. In the pressure converter for obtaining an electric signal corresponding to, the one rigid member constituting the introduction passage forming member forming the introduction passage for guiding the fluid from the pressure detection object to the pressure receiving diaphragm, A hollow first introduction member whose end is directly or indirectly connected to the detection object, and a seal member formed in an annular shape and abutting on the end surface of the first introduction member on the non-pressure detection object side. And the other rigid member that constitutes the introduction passage forming member that forms the introduction passage, and on the end surface of the first introduction member on the non-pressure detection target side via the seal member. It is possible to detachably join the first introducing member and the second introducing member at a location that does not directly contact the fluid and the second introducing member that is detachably joined. A coupling means configured to keep the sealing member compressed in its thickness direction, and integrally or integrally with the second introduction member in a state of blocking the introduction passage inside the second introduction member. A rigid body of the second introducing member, which is formed and is caused by a bending moment generated in a joint portion of the second introducing member when the second introducing member is joined to the first introducing member by the coupling means. The pressure receiving diaphragm provided so as to be positioned on the stress neutral surface that is not affected by the compressive stress and the tensile stress generated in the inner wall portion of the section, and is attached to the surface of the pressure receiving diaphragm on the non-pressure detection target side. Pressure transducer having a sanitary property, wherein said strain gauges, that it has been composed. 2. The pressure applied from the pressure detection target by applying the fluid from the pressure detection target as a pressure medium to the pressure reception diaphragm to deform it and detecting the deformation amount of the pressure detection diaphragm with a strain gauge. In a pressure converter that outputs an electric signal corresponding to, one rigid member that constitutes an introduction passage forming member that forms an introduction passage for guiding a fluid from the pressure detection target to the pressure receiving diaphragm, A hollow first introduction member whose end is directly or indirectly connected to the pressure detection target, and a ring-shaped member which is detachably attached to the end face of the first introduction member on the non-pressure detection target side. A seal member and the other rigid member constituting the introduction passage forming member forming the introduction passage, the non-pressure detection of the first introduction member via the seal member. It is possible to detachably couple the first introducing member and the second introducing member to a second introducing member that is detachably connected to the end surface on the output target side and a portion that does not directly contact the fluid. It is possible, and by this coupling operation, the coupling means configured to keep the seal member compressed in the thickness direction thereof, and the second introduction member in a state of blocking the introduction passage inside the second introduction member. Due to a bending moment which is formed integrally with or integrally with the introduction member, and when the second introduction member is joined to the first introduction member by the joining means, the bending moment is generated in the joint portion of the second introduction member. Of the pressure receiving diaphragm provided so as to be located on a stress neutral surface that is not affected by compressive stress and tensile stress generated in the inner wall portion of the rigid body portion of the second introducing member, and the pressure receiving diaphragm of the pressure receiving diaphragm. A thin strain element that is connected to a force transmission member provided at the center of the surface on the side of the pressure detection object, and whose end is integrally or integrally formed with the second introduction member, and this strain element. A pressure transducer having a hygienic property, comprising: the strain gauge attached above.