JPH0762640B2 - Differential pressure detector - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention includes a detection unit that outputs a signal corresponding to a differential pressure to be measured, and a detection diaphragm that is provided outside the detection unit and that protects the detection unit against each introduced pressure that causes a differential pressure. The present invention relates to an apparatus, and more particularly to a differential pressure detection apparatus improved so as to suppress zero-point fluctuation. It should be noted that this differential pressure detection device becomes a pressure detection device for gauge pressure or absolute pressure because one of the introduction pressures is atmospheric pressure or vacuum.

[Prior art]

A conventional device will be described with reference to FIG. 7, which is a cross-sectional view. In FIG. 7, the conventional device is roughly divided into a detection unit 20 and a protection unit 30, which are pressure guide tubes 6,
Connected via 7. The detection unit 20 converts the differential pressure to be measured into an electric signal and outputs the electric signal, and the protection unit 30 protects the detection unit 20 against the introduced pressure, which will be described later in detail. This detector
Since the configuration of 20 is well known, the description thereof will be omitted. Although there is another conventional device in which the detection unit 20 is internally provided in the protection unit 30, the purpose of the configuration in which the detection unit 20 is externally provided in the protection unit 30 is that when the measurement fluid has a high temperature. This is to prevent the influence of temperature from affecting the detection unit 20. Now, the protection part 30 mainly comprises the main bodies 31 and 32, the protection diaphragm 3, the seal diaphragms 4 and 5, the O-ring 8 and the cover 9. Here, the members having the same names of the main bodies 31 and 32 and the seal diaphragms 4 and 5 are the same, and
There are two rings 8 and two covers 9. Main bodies 31 and 32 are respectively arranged on the left and right sides with the protective diaphragm 3 interposed therebetween, and are joined to each other at their outer circumferences or peripheral portions. Further, in the main bodies 31 and 32, the same recesses 11 and 21 and holes 14 and 2 are respectively
4 and holes 45, 55 are formed. More specifically, the main body 31 on the right side is described as follows. Recess 11
Is formed on the left side of the body 31 in the shape of a mortar that is coaxial with this,
Reference numeral 14 penetrates the main body 31 along its axis, and the hole 45 opens on the one hand in the vicinity of the outer periphery of the recess 11 and, on the other hand, penetrates the pressure guiding tube 6 and communicates with a pressure guiding space (not shown) of the detecting section 20. . Body 31
The right side surface of the main body 31 has a corrugated cross section, and the seal diaphragm 4 having substantially the same shape as the corrugated shape is fixed to the right side surface of the main body 31 at its peripheral edge with a space. A cover 9 is attached to the right side of the main body 31 on the outer peripheral edge of the seal diaphragm 4 via an O-ring 8. The above is substantially the same for the left main body 32. And the space that contacts the seal diaphragms 4 and 5,
In the space consisting of the holes 14 and 24, the recesses 11 and 21 and the holes 45 and 55,
Each is filled with silicone oil (filled liquid) as a fluid for pressure transmission. The operation of this conventional device is as follows. Differential pressure flow meter,
For example, each introduced pressure on both sides of the orifice (including static pressure)
However, when pressure is received by the seal diaphragms 4 and 5, respectively,
The respective introduction pressures are passed through the space contacting the seal diaphragm 4, the hole 14, the recess 11 and the hole 45 to one pressure guiding space of the detection unit 20, and the space contacting the seal diaphragm 5 and the hole 2.
It is transmitted to the other pressure guiding space of the detecting section 20 through the concave portion 21 and the hole 55. The seal diaphragms 4 and 5 have extremely small spring constants (soft), the detection diaphragm (not shown) of the detection unit has extremely large spring constants (rigid), and the protective diaphragm 3 has the above spring constants. Takes two intermediate values of. The detection unit 20 converts the differential pressure based on each introduction pressure into an electric signal by a known method, for example, a capacitance method, and outputs the electric signal. The above is the case where the normal pressure introduction operation is performed. However, due to an incorrect operation, the right seal diaphragm 4
If only the pressure is received, the detection unit 20 may be subjected to a large one-sided pressure and the sensor may be damaged if the protection unit 30 is not provided. Even if only one of the pressures is received by the seal diaphragm due to an erroneous operation in introducing each pressure on both sides of the orifice, the protection unit 30 protects the detection unit 20 by the following operation. In FIG. 7, assuming that only the seal diaphragm 4 receives pressure, this pressure is applied from the hole 14 and the recess 11 via the filled liquid, and on the other hand, via the protective diaphragm 3 to the left recess 2
1, transmitted through the hole 24 to inflate the seal diaphragm 5. On the other hand, it is transmitted to the pressure guiding space on the right side of the detecting portion 20 via the hole 45. However, this transmission pressure is limited to a certain value or less by the contact of the seal diaphragm 4 with the corrugated surface on the right side of the opposing main body 31, so that the sensor is not damaged and the protection function is not activated. Become.

[Problems to be Solved by the Invention]

As described above, according to the conventional technique, if the protective diaphragm 6 is made as soft as possible and, in other words, is largely displaced by a small pressure, the one-sided pressure transmitted to the detection unit 20 can be suppressed. Moreover, at this time, the protective diaphragm 6 must be protected from damage by not increasing the stress generated in itself. Therefore, conventionally, a method of stacking a plurality of diaphragms may be used as the protective diaphragm. However, in this method, due to the surface friction between the diaphragms adjacent to each other, when the acting one-sided pressure is removed, it does not completely return to the initial position, that is, residual displacement occurs, and as a result, zero point fluctuation occurs. There is. An object of the present invention is to provide a differential pressure detecting device which solves the above problems of the conventional technique and improves so as to suppress the zero point fluctuation.

[Means for Solving the Problems]

In order to solve this problem, in the first differential pressure detecting device according to the present invention, a protective diaphragm includes a disk-shaped central diaphragm, and the central diaphragm is laminated on each side of both sides of the central diaphragm. And one or more side diaphragms having a circular hole and having a disk shape with the same diameter as the central diaphragm. A second differential pressure detecting device according to the present invention is characterized in that a protective diaphragm has a disk-shaped central diaphragm and is laminated on each side of both sides of the central diaphragm and has a circular hole at the center thereof. And one or more side diaphragms having a disk shape with the same diameter as that of the central diaphragm and curved toward the center of the central diaphragm in a convex shape. In the third differential pressure detecting device according to the present invention, the protective diaphragm comprises a plurality of disk-shaped first diaphragms; a small disk in the center, and concentric therewith, and the same diameter as the first diaphragm. One or more second diaphragms each having a circular ring at its peripheral portion and having a plurality of arms as bridging portions between the small disk and the circular ring; and the first and second diaphragms. Are alternately laminated on the outermost side so that the first diaphragms are located respectively.

[Work]

In the first differential pressure detecting device according to the present invention, the central diaphragm and the side diaphragm adjacent to the central diaphragm,
Further, the friction that may occur due to the radial deviation of the central portions between the adjacent side diaphragms at the time of deformation is removed, and the surface frictional force between the respective side diaphragms is reduced. In the second differential pressure detecting device according to the present invention, the central diaphragm and the adjacent side diaphragm,
In addition, friction that may occur due to radial displacement at the center between the adjacent side diaphragms during deformation is eliminated, and the above-mentioned diaphragms are brought into a pressure contact state. As the frictional force decreases, the degree of adhesion between the diaphragms increases. In the third differential pressure detecting device according to the present invention, since the first diaphragms that are adjacent to each other are in contact with each other via the second diaphragm located in the middle, and only the small disk portion is in contact, the surface friction between them is The power decreases.

【Example】

A first embodiment of the differential pressure detecting device according to the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a protective diaphragm in the first embodiment, and FIG. 2 is a front view of the same. In FIG. 1, the protective diaphragm 60 comprises a central diaphragm 61 and side diaphragms 62 arranged adjacent to each side thereof. Although the central diaphragm 61 and the diaphragms 62 on each side are both flat disk-shaped with the same diameter, the central diaphragm 61 has no hole in the center, whereas the diaphragm 62 on each side has a hole 62a in the center. Therefore, the presence of the hole 62a eliminates the friction that may occur due to the radial displacement at the time of deformation in the central diaphragm 61 and the central portion between the adjacent side diaphragms 62, and the surface friction force between each other is eliminated. Decrease. As a result, the protective diaphragm 60 returns almost completely to the initial position when the partial pressure acting on it is removed, and as a result, the zero point fluctuation is suppressed. It should be noted that, in general, there may be more than one side diaphragm on each side of one central diaphragm 61. Of course, the plate thickness of the side diaphragm in this case is made thinner than that in the first embodiment. A second embodiment of the differential pressure detecting device according to the present invention will be described below with reference to the drawings. FIG. 3 is a side sectional view of the protective diaphragm in the second embodiment before assembly, and FIG.
The figure is also a front view thereof. In FIG. 3, the protective diaphragm 70 comprises one central diaphragm 71 and side diaphragms 72 arranged adjacent to each side thereof. The central diaphragm 71 and the diaphragms 72 on each side are both disk-shaped with the same diameter, but the central diaphragm 71 has no hole in the center and is flat, whereas the diaphragms on each side are centered. Hole in the part
72a, which is convexly curved toward the central diaphragm 71. Therefore, the central diaphragm 71 and the diaphragms 72 on each side are
When and are stacked and assembled, the presence of the hole 72a
The friction between the central diaphragm 71 and the diaphragms 72 on each side, which may occur due to the radial displacement during deformation, is eliminated, and the diaphragms on each side are deformed when standing up, causing pressure contact between the diaphragms. And the degree of adhesion between each diaphragm increases. as a result,
The protective diaphragm 70 returns almost completely to the initial position when the partial pressure acting on it is removed, and as a result, the zero point fluctuation is suppressed. It should be noted that, in general, there may be more than one side diaphragm on each side of one central diaphragm 71. Of course, the thickness of the side diaphragm in this case is thinner than that in the second embodiment. A third embodiment of the differential pressure detecting device according to the present invention will be described below with reference to the drawings. FIG. 5 is a side sectional view of the protective diaphragm in the third embodiment, and FIG. 6 is a front view of its main members. In FIG. 5, the protective diaphragm 80 is composed of two first disk-shaped first diaphragms 81 and a second diaphragm 82 inserted in the middle thereof. Second diaphragm 82
As shown in FIG. 6, has a small disk 82a at the center and a circular ring 82b concentric therewith and having the same diameter as the first diaphragm 81 at the peripheral edge, and has four arms with the small disk 82a and the circular ring 82a. It also serves as a bridge with 82b. Therefore, the first diaphragms 81 adjacent to each other are in contact with each other only through the second diaphragm 82 located in the middle, and only the small disk 82a except the peripheral edge.
The surface friction force during that time decreases. As a result, the protective diaphragm 80 returns almost completely to the initial position when the partial pressure acting on it is removed, and as a result, the zero point fluctuation is suppressed. Generally, each of the first and second diaphragms is provided in a plurality and one or more, respectively, and the first and second diaphragms may be alternately and outermostly laminated. Of course, in that case, the plate thickness of each first diaphragm is made thinner than in the third embodiment.

【The invention's effect】

Common to the first, second, and third differential pressure detection devices according to the present invention,
Compared with the prior art, the protective diaphragm has an excellent effect that it returns almost completely to the initial position when the partial pressure acting on it is removed, and as a result, the zero point fluctuation is suppressed.

[Brief description of drawings]

1 is a side sectional view of a protective diaphragm in a first embodiment according to the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a side sectional view of a protective diaphragm in a second embodiment according to the present invention before assembly. 4 and 5 are front views of the same, FIG. 5 is a side sectional view of a protective diaphragm according to a third embodiment of the present invention, FIG. 6 is a front view of the same main members, and FIG. It is a sectional side view. Code Description 60,70,80: Protective diaphragm, 61,71: Central diaphragm, 62,72: Side diaphragm, 62a, 72a: Hole, 81: 1st diaphragm, 82: 2nd diaphragm, 82a: Small disk, 82b: Torus, 82c: Arm.

Claims (3)

[Claims] 1. A detection unit that outputs a signal according to a differential pressure to be measured, and a protective diaphragm that is provided outside the detection unit and protects the detection unit against each introduced pressure that causes the differential pressure. In the detection device, the protective diaphragm includes one disk-shaped central diaphragm; a disk having the same diameter as the central diaphragm, which is laminated on each side of both sides of the central diaphragm and has a circular hole in the center. Form 1
A differential pressure detecting device comprising: one or more side diaphragms; 2. A detection section for outputting a signal according to a differential pressure to be measured, and a protective diaphragm externally provided to the detection section for protecting the detection section against each introduced pressure that causes the differential pressure. In the detection device, the protective diaphragm includes one disk-shaped central diaphragm; a disk having the same diameter as the central diaphragm, which is laminated on each side of both sides of the central diaphragm and has a circular hole in the center. 1. A differential pressure detecting device, comprising: one or more side diaphragms that have a shape and are curved in a convex shape toward the center of the central diaphragm. 3. A detection section for outputting a signal according to a differential pressure to be measured, and a protective diaphragm provided outside the detection section for protecting the detection section against each introduced pressure that causes the differential pressure. The protective diaphragm comprises a plurality of disk-shaped first diaphragms;
A second disc having a small disc at the center and a concentric ring having the same diameter as the first diaphragm at the peripheral edge, and a plurality of arms serving as a bridge between the small disc and the circular ring. And at least one of the diaphragms of the above, and the first and second diaphragms are laminated alternately and on the outermost side, the first diaphragms are respectively laminated.