JP3314538B2 - Differential pressure transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure transmitter and, more particularly, to a differential pressure transmitter for preventing a change in a zero point of a center diaphragm and a deformation of a pressure receiving member and accurately detecting a differential pressure.

[0002]

2. Description of the Related Art The structure of a pressure receiving portion of a conventional differential pressure transmitter generally includes a main body H and a main body H, as described in JP-A-60-185131 (see FIG. 2). The main body H has a seal diaphragm fixed on one surface and a sensor section and a center diaphragm fixed on the other surface.

The main body L and the main body L are overlapped and the outer periphery thereof are welded so that the seal diaphragm is also fixed to one side of the main body L and the other side presses the center diaphragm of the main body H. Further, on both sides of the main body composed of the main bodies H and L, first and second pressure receiving chambers formed by seal diaphragms for receiving the first and second fluids are formed. A first diaphragm and a second isolation chamber are provided by the center diaphragm and the main body L, and a pressure guiding path connecting the first pressure receiving portion and the first isolation chamber, and a pressure guiding path connecting the first isolation chamber and the semiconductor differential pressure sensor. , A pressure guiding path connecting the second pressure receiving chamber and the second isolation chamber, and a pressure guiding path connecting the second isolation chamber and the semiconductor differential pressure sensor.

[0004] The first pressure receiving chamber, the first isolation chamber, the semiconductor differential pressure sensor, and the pressure guiding path connecting them are filled with a filling liquid. Similarly, the second pressure receiving chamber, the second isolation chamber, the semiconductor pressure differential pressure sensor, and the pressure guiding path connecting them are also filled with the filling liquid, and the pressure is transmitted to the semiconductor differential pressure sensor.

In the conventional differential pressure transmitter, a flange is attached to a place facing the seal diaphragm, and the main body H,
The pressure from the process fluid is transmitted to the respective pressure receiving chambers by tightening and fixing the L and the flange with bolts and nuts. Then, in maintenance of the differential pressure transmitter, in order to inspect the first and second seal diaphragms joined to both sides of the pressure receiving member, the bolts tightening the pressure receiving member and the flange are loosened, and the pressure receiving member is loosened. The seal diaphragm was inspected after taking out.

[0006]

In the pressure receiving section of the conventional differential pressure transmitter, the main body member is composed of a main body H and a main body L, and the main body H and the main body L are fixed by welding with the center diaphragm interposed therebetween. I have. Therefore, the shape and position of the center diaphragm are determined by the pressing force generated by welding the main body H and the main body L.

[0007] The measuring fluid pressure receiving chamber has two main bodies H and L.
It is sandwiched from both sides by individual flanges, and tightened and fixed with bolts and nuts to form. The tightening force of the flange affects the shape and position of the center diaphragm because the main body H and the main body L are pressed from both ends, and the tightening force of the flange is statically applied to the first and second measurement fluid pressure receiving chambers. Even when pressure was applied, it changed according to the pressure.

As described above, the welding of the main body H and the main body L and the tightening force of the flange are major factors that change the shape and position of the center diaphragm. As a result, the sealed liquid was displaced, and the seal diaphragm was deformed, and this effect appeared as a change in the zero point, which hindered accurate differential pressure measurement.

In maintenance of the differential pressure transmitter, the operation was difficult because the pressure receiving member and the flange were separated, and then the pressure receiving member was taken out and the seal diaphragm was inspected.

[0010]

SUMMARY OF THE INVENTION The feature of the present invention is a process.
A first pressure receiving chamber for receiving a first pressure of the process fluid;
A second pressure receiving chamber for receiving a second pressure of the fluid,
A first isolation chamber to which the pressure applied to one pressure receiving chamber is transmitted
The pressure applied to the second pressure receiving chamber is transmitted.
Second isolation room and the first and second isolation rooms.
Differential pressure transmission with differential pressure sensor for detecting each pressure
Wherein the first, second and third diaphragms are simply
In the recess provided at each different position of one pressure receiving member
The first pressure receiving chamber is welded to the first die.
The first member is joined to the pressure receiving member by the
A second member formed between the diaphragm and the pressure receiving member;
In the pressure receiving chamber, the second diaphragm is in contact with the pressure receiving member.
By being combined, the second diaphragm and the pressure receiving member
And the first isolation chamber is formed between the third
The third dam is formed by joining the flam to the pressure receiving member.
A second diaphragm formed between the ear ram and the pressure receiving member;
The chamber is machined in the same manner as the shape of the third diaphragm.
The third diaphragm is provided with a fixing bracket having an inclined surface.
It is formed by fitting into the
The metal fitting is a welding position between the third diaphragm and the pressure receiving member.
A convex portion that contacts the third diaphragm is provided inside the
Has a fitting with the third diaphragm through the convex portion
Is to be done.

[0011]

[0012]

[0013]

The operation of the differential pressure transmitter according to the present invention will be described below in comparison with a conventional differential pressure transmitter.

In the conventional differential pressure transmitter, the first and second seal diaphragms, the center diaphragm, and the sensor assembly are provided side by side on the same axis, so that the members supporting the respective diaphragms are joined together. Also, when pressure is applied to the member supporting the seal diaphragm from the measurement fluid, the shape and position of the center diaphragm are distorted, and the zero point is changed. On the other hand, in the differential pressure transmitter of the present invention, since the pressure receiving direction of the center diaphragm is provided in a direction different from the pressure receiving direction of the first and second seal diaphragms, the seal diaphragm is joined to the pressure receiving member. Even in such a case, the distortion generated at this time is not transmitted to the center diaphragm, so that when the respective diaphragms are joined to the pressure receiving member, the distortion at the time of joining is not transmitted to each other.

Further, since the operation supporting point of the center diaphragm is clarified by the member forming the isolation chamber of the pressure receiving portion, the operation of the center diaphragm is also clarified. Does not occur.

Furthermore, since the pressure receiving member is firmly joined and sealed to the main body member of the pressure receiving member by screwing or welding, the amount of deformation under a pressure load can be reduced, and the zero point change can be reduced. .

When the differential pressure transmitter is used, even when an excessive pressure is applied to the member supporting the seal diaphragm from the measurement fluid chamber, these distortions hardly affect the center diaphragm.

Further, since the first and second pressure receiving chambers can be provided close to the first and second isolation chambers, respectively, the path of the pressure guide path in which each pressure chamber is provided can be shortened. Can be.

Further, since the measuring fluid pressure receiving chamber is constituted by the members constituting the pressure receiving chamber, and the member is provided with an opening directly connected to the process pipe, the flange which has been conventionally required can be eliminated, and maintenance can be performed. Is easy.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A differential pressure transmitter according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a differential pressure transmitter according to the present invention. This differential pressure transmitter mainly comprises a pressure receiving member 20, a sensor assembly 2, seal diaphragms 6, 7, Load protection diaphragm 4, first and second pressure receiving chambers 201,
02, first and second isolation chambers 203 and 204.

FIG. 3 is a detailed view of the pressure receiving member 20 shown in FIG. The pressure receiving member 20 is formed of a single member, and holes 21 and 22 for symmetrically attaching the seal diaphragms 6 and 7 are provided at both ends of the pressure receiving member 20, and the bottom surface has the same shape as the seal diaphragms 6 and 7. Processing, hole 2
Screw holes 37, 38 having a diameter larger than the seal diaphragms 6, 7 for fixing the stoppers 35, 36 are provided at the inlets of the holes 1 and 22.
Is formed.

FIG. 4 is a sectional view taken along line aa of FIG.

The pressure receiving member 20 is formed with a tapered screw 28 on the upper side of the hole 22 for mounting the seal diaphragm 7 and a tapered screw 30 on the lower side, respectively. It is connected. Similarly, in the hole 21, tapered screws 27 and 29 (not shown) are machined in upper and lower portions, respectively.
They are connected by conduction paths 31 and 33.

On the central axis of the pressure receiving member 20, a sensor assembly storage hole 23 for accommodating the overload protection diaphragm 4 and the sensor assembly 2 is provided with seal diaphragms 6,7.
And at right angles. On the small diameter side of the stepped hole 23, a hole 9 for mounting with an amplifier is provided, and on the large diameter side, a hole 10 for mounting a fixing metal 8 for fixing the overload protection diaphragm 4 is provided.

A conduction path 2 is provided between the seal diaphragms 6 and 7, the overload protection diaphragm 4 and the sensor unit 2.
4, 25 and 26 are connected.

The structure of the first pressure receiving chamber 201, the second pressure receiving chamber 202, the first isolation chamber 203, and the second isolation chamber 204 in the differential pressure transmitter according to one embodiment of the present invention will be described with reference to FIG. explain.

In the differential pressure transmitter according to the present embodiment, the seal diaphragms 6, 7 are inserted through the holes 21 and 22 of the pressure receiving member 20.
And the first and second pressure receiving chambers 201 and 202 are formed by welding so that the surfaces of the seal diaphragms 6 and 7 are parallel to each other.

Next, the stoppers 35 and 36 are screwed into the screw holes of the pressure receiving member 20, and the end faces thereof are joined and sealed by welding to form measurement fluid pressure receiving chambers 17 and 18.

The sensor assembly 2 is inserted into the sensor assembly storage hole 23 at the center of the pressure receiving member 20 from the larger diameter direction, and the conduction path 60 of the sensor assembly 2 and the conduction path 25 of the pressure receiving member 20 are inserted. Are assembled so as to conduct, and both ends of the sensor assembly 2 are welded.

After that, the center metal fitting 5 is placed in a position where the conductive path 61 of the center metal fitting 5 and the conductive path 24 of the pressure receiving member 20 are connected to each other, and the surface of the overload protection diaphragm 4 machined in the same wave shape is overloaded. Attach it to the protection diaphragm 4 side, and further attach
0 to form a first isolation chamber 203. A conduction path 63 for transmitting pressure from the overload protection diaphragm 4 to the semiconductor differential pressure sensor 44 is provided at the center of the center fitting 5.

The conduction path 62 of the spacer 80 located on the lower surface of the fixture 8 and the pressure receiving member 20
A surface of the overload protection diaphragm 4 machined in the same shape as that of the overload protection diaphragm 4 is attached to the overload protection diaphragm 4 side so that the conduction path 26 is electrically connected, and a threaded portion formed by the fixture 8 and the pressure receiving member 20. The screw portion of the fixing bracket 8 is screwed in, and its end is sealed by welding.
04 is formed. Next, the seal diaphragm 6, the overload protection diaphragm 4, the sensor assembly 2, the conduction paths 24, 6
1,63, in a space surrounded by the sealing pin 51 of Ekifuguchi, Yes sealed liquid 15 is filled, likewise sealed diaphragm 7, the overload protection diaphragm 4, the sensor unit assembly 2, guide <br/> communication path 25, 26, 60, 62, seal bottle 52 for liquid sealing
The space 16 is also filled with the filling liquid 16.

FIG. 6 is a view showing in detail the overload protection diaphragm 4, the pressure receiving member and the fixing bracket 8 shown in FIG. The overload protection diaphragm 4 is welded to the pressure receiving member, and the inside of the welded portion is brought into contact with and pressed against the end face of the fixing metal when the fixing metal is screwed into the pressure receiving member 20 by the convex portion 681 of the spacer 81. The fixing bracket 8 is welded and sealed with an argon arc at the pressure receiving member 20 and at its end face. Therefore, the fulcrum of movement of the center diaphragm is firmly pressed, so that there is no influence of distortion, and the fulcrum of movement is always clarified. Further, when a pressure is applied, a large differential pressure is generated between the isolation chamber 204 and the end surface (atmosphere side) of the fixture, and the fixture 8 is elastically deformed, and the deformation may move the enclosed liquid and change the zero point. However, since the length of the screw joint 683 of the fixing bracket 8 is sufficiently ensured, the deformation amount is very small. For this reason, the influence of the zero point is small.

The sensor assembly 2 includes a semiconductor differential pressure sensor 44 and a hermetic seal bin 45, and the FPC 46 solders the hermetic seal bin 45 to the atmospheric pressure release side, which is necessary for a conventional differential pressure transmitter. The need to provide a hole in the pressure receiving member 20 for extracting a sensor signal is eliminated.

The amplifier case 47 is inserted into the amplifier mounting hole 9, the metal 14 is inserted into a groove formed by the pressure receiving member 20 and the amplifier case 47, and the amplifier case 47 is connected to the pressure receiving member 20 by metal flow bonding. Fixed to.

The differential pressure detecting operation of the differential pressure transmitter having such a configuration will be described with reference to FIG. When the first pressure from the process fluid is applied to the seal diaphragm 6, the first pressure of the measurement fluid is transmitted to the sealed liquid 15 in the first pressure receiving chamber 201 on the back side of the seal diaphragm 6 via the seal diaphragm 6. Furthermore, this first pressure is applied to the conduit 24,
The light is transmitted to the first isolation chamber 203 formed between the overload protection diaphragm 4 and the center metal member 5 through 61, and further transmitted to the semiconductor differential pressure sensor 44 through the conduction path 63 of the center metal member 4. Also, when the second pressure from the process fluid is applied to the seal diaphragm 7, the second pressure of the measurement fluid is transmitted to the sealed liquid 16 in the second pressure receiving chamber 202 via the seal diaphragm 7 in the same manner. The second pressure is applied to the second isolation chamber 204 formed between the overload protection diaphragm 4 and the fixture 8 by the passages 25 and 26.
Is transmitted to the back surface of the sensor by the conduction path 60. As described above, the semiconductor differential pressure sensor 44 detects the first and second pressures of the measurement fluid transmitted to the front and back of the center diaphragm, and the output of the semiconductor differential pressure sensor 44 is taken out from the hermetic seal pin 45 to the atmosphere open side. And transmitted to the amplifier via the FPC 46.

The measuring fluid pressure receiving chambers 17 and 18 are
Since it is formed within 0, there is no need for a flange or bolts and nuts for fastening the flange, unlike the conventional example. That is, it is only necessary to provide the plugs 35 and 36 for forming the measurement fluid pressure receiving chambers 17 and 18.

As shown in FIG. 5, an adapter 43 and a gasket 48 are fastened and fixed to one of the connection ports of the pressure receiving member 20 by bolts 50 as shown in FIG. Piping 41
Is screwed into the adapter 43 for use. The other connection port of the pressure receiving member 20 has a drain / vent plug 3
9 can be attached, and the connection of the process pipe connection and the connection of the drain / vent plug 39 can be made both up and down or at right angles.
In the figure, the adapter 43 is used to connect the pipe 41 to the pressure receiving member 20. However, the pipe 41 can be directly joined by cutting a taper screw into the pressure member 20.

As described above, according to the differential pressure transmitter of the present invention, the pressure receiving direction of the seal diaphragm is arranged at right angles to the pressure receiving directions of the first and second seal diaphragms. Compared with the conventional example in which the diaphragm is welded to the member 20 as compared with the conventional example in which the diaphragm is arranged on the same axis, no distortion occurs in the shape and the position of the seal diaphragm because the distortion is not transmitted.

Also, due to the arrangement in the right angle direction, even when an excessive pressure is applied from the process fluid to the measurement fluid pressure receiving chambers 17 and 18, the distortion of the member generated in the vicinity of the seal diaphragm is not easily transmitted to the center diaphragm as distortion. Therefore, there is no change in the zero point of the overload protection diaphragm and no change in its fulcrum, and the differential pressure can be accurately measured.

Further, according to the differential pressure transmitter of the present invention, since the measurement fluid pressure receiving chambers 17 and 18 can be formed in the pressure receiving member 20, the pressure receiving member 20 can be formed as a single component, and the measurement fluid pressure receiving chamber 17 can be formed. , 18 do not require flanges, bolts and nuts. Therefore, there is no change in the shape of the pressure receiving member 20 due to the tightening of the bolts and nuts, and no deformation of the pressure receiving member main body when one-sided pressure or excessive static pressure is applied to the measurement fluid pressure receiving chambers 17 and 18. The differential pressure can be measured more accurately without changing the zero point or the supporting point.

FIGS. 7 and 8 show modified examples of the mounting of the fixing bracket.

FIG. 7 shows that a fixing portion 8 is provided with a convex portion 781 for clarifying the fulcrum of movement of the overload protection diaphragm 4, and the pressure receiving member and the fixing portion 8 are connected to the center diaphragm 4.
In a position very close to (the position close to the isolation chamber on the circumferential surface to be fitted).
The welding depth of this weld is a welding method that can ensure sufficient strength against the working pressure of the differential pressure transmitter (electron beam welding, etc.)
Can be realized by: According to such a configuration, the number of pressure receiving members is reduced, and the space in the circumferential direction of the fixing bracket can be eliminated, so that the amount of the sealed liquid can be reduced and further downsizing can be achieved. Further, when a pressure is applied, no pressure acts on the cylindrical surface of the hole 10 (FIG. 3) of the pressure receiving member, so that there is no deformation. For this reason, the zero point change due to deformation can be further suppressed, and an accurate differential pressure can be measured.

[0044] Figure 8 is than also constitute a fixing bracket in two parts 83 and 84, member 83 has a convex portion 881 to clarify the movement fulcrum of the center diaphragm 4, further isolation chamber 204 is formed. Further, the circumferential portion is welded in the same manner as in the embodiment of FIG. Next, since the member 84 is screwed into the threaded portion of the pressure receiving member 20 with a predetermined torque via the groove 884, an initial strain is applied to the member 83. Can be. The member 8
4 has its end sealed by welding. According to such a configuration, the zero point error due to the deformation of the pressure receiving member can be further reduced, and the reliability is improved because the welded portion requiring reliability is not exposed.

FIG . 9 shows the process measurement in the tank.
Widely used for measuring pressure, liquid level and density
Diaphragm replacer type differential pressure transmitter according to the present invention.
It shows a configuration when a pressure receiving section is applied. FIG.
The plugs 35 and 36 are provided with micro holes 935 and 936, and the shape is changed to a shape having a minute space so that another pressure receiving chambers 921 and 922 can be formed on the opposing surfaces of the pressure receiving chambers 201 and 202. than it is. Such a structure is used for a pressure receiving section of a diaphragm replacer type differential pressure transmitter which is widely used for measuring the liquid level and density in a tank by process instrumentation (the broken line in the figure indicates the case of the diaphragm replacer type). This example can be easily applied. This plug is only required to be replaced with the plugs 35 and 36 at the time of assembling, so that the plug is excellent in assemblability and expandability. Further, in the pressure receiving portion of the diaphragm replacer type differential pressure transmitter, the screw hole of the pressure introduction port shown in FIG. 1 is not required at all, and the economy is excellent.

[0046]

In the conventional diaphragm replacer type differential pressure transmitter, when the distal end of the diaphragm replacer type differential pressure transmitter is attached to the pressure receiving portion, it must be joined through a special member. Since the distortion at that time affects the basic pressure characteristics of the pressure receiving portion, the characteristics have changed. Further, the cost is inevitably increased due to the necessity of this special component.

On the other hand, the diaphragm replacer type differential pressure transmitter of the present invention has a basic structure of a pressure receiving portion shown in FIG. 1, and a structure for transmitting the pressure from the diaphragm replacer portion to this pressure receiving portion. A configuration is adopted in which a member is added and joined to the pressure receiving portion and sealed.

According to the present invention, a diaphragm replacer type differential pressure transmitter can be constructed by simply changing the configuration of the plugs 35 and 36 into a member shape as shown in FIG.

The stoppers 35 and 36 have fine holes 935 and 936, respectively.
Are provided, and another pressure receiving chamber 921, 922 is formed on the surface facing the pressure receiving chambers 201, 202, so that the pressure receiving chambers are changed into a shape having a minute space.

The other end faces of the plugs 35 and 36 are joined and sealed with constituent members for transmitting pressure with the diaphragm replacer portion, respectively, to form micro holes 935 and 936.
The pressure from the diaphragm replacer section is transmitted via the pressure sensor.

FIG. 10 shows an embodiment of a configuration example of a portion of a diaphragm replacer type differential pressure transmitter which directly receives a process fluid.

The process connection diaphragm 952 is joined and sealed to the process connection member 953 by welding.
A pressure receiving chamber 260 is formed between the pressure receiving chamber 53 and the pressure receiving chamber 53. Further, this connection member 953 is fixed and integrated with a bolt 955 via a process connection flange 954 conforming to the shape on the process side so as to be attached to a flange of a process pipe, a tank or the like. Further, on the outer periphery of the process connection member 953, a component member 951 for transmitting a process pressure to the plugs 35 and 36 is attached. Silicon oil is sealed in the space created in such a configuration, and each pressure of the process is controlled by the diaphragm 952, the pressure receiving chamber 260, the pressure guiding paths 958, 951, and the stoppers 35, 36.
Is transmitted to the semiconductor differential pressure sensor 44 via the sensor and the differential pressure can be detected.

According to such a configuration, it is possible to change to a diaphragm replacer type pressure receiving chamber simply by changing the plugs 35 and 36 constituting the basic pressure receiving portion as shown in the drawing, and to add an additional component to the pressure receiving portion side. Can be configured without any need.

Further, the expandability is excellent without impairing the basic differential pressure detecting characteristics of the pressure receiving portion.

[0056]

According to the differential pressure transmitter of the present invention, when the center diaphragm is joined to the pressure receiving member main body, and even when an excessive pressure is applied from the process fluid, the generated strain does not affect the center diaphragm. Since there is no change in the shape and position and the zero point is not affected, and the zero point error due to the deformation of the pressure receiving member at the time of pressure load can be reduced, there is an effect that an accurate differential pressure can be detected, and the entire transmitter can be detected. Can be reduced in size.

Further, since the measurement fluid pressure receiving chamber is constituted by the pressure receiving member, a flange is not required, and a single component of the pressure receiving member and a stopper make it possible to further reduce the size.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a differential pressure transmitter according to the present invention.

FIG. 2 is a longitudinal sectional view of a conventional differential pressure transmitter.

FIG. 3 is a longitudinal sectional view of the pressure receiving member of FIG. 1;

FIG. 4 is a sectional view taken along a line aa in FIG. 3;

FIG. 5 is a longitudinal sectional view showing a piping example of the differential pressure transmitter according to the present invention.

FIG. 6 is an enlarged view of a center diaphragm mounting portion and a fixing bracket mounting portion.

FIG. 7 is a cross-sectional view of another embodiment in which a center diaphragm is attached.

FIG. 8 is a cross-sectional view of another embodiment in which a center diaphragm is attached.

FIG. 9 is a sectional view of an embodiment of a diaphragm replacer type pressure receiving portion.

FIG. 10 shows a distal end of a diaphragm replacer.

[Explanation of symbols]

2 ... Sensor assembly, 4 ... Overload protection diaphragm, 5 ... Center bracket, 6,7 ... Seal diaphragm, 8 ... Fixing bracket, 9 ... Amplifier mounting hole, 10 ... Fixing bracket mounting hole, 14 ...
Metal, 15, 16 ... Filled liquid, 17, 18 ... Measurement fluid pressure receiving chamber, 20 ... Pressure receiving member, 21, 22 ... Seal diaphragm mounting hole, 23 ... Sensor assembly storage hole, 24, 2
5,26,31,32,33,34,60,61,6
2, 63: conduction path, 27, 28, 29, 30: tapered female thread, 35, 36: plug, 37, 38: screw hole, 39 ...
Drain / vent plug, 41 pipe, 43 adapter, 44 semiconductor differential pressure sensor, 45 hermetic seal bottle, 46 FPC, 47 amplifier case, 48 gasket, 50 bolt, 51, 52 seal pin, 5
3, 54: liquid seal, 81: spacer, 83, 84: Modified example of fixing bracket, 101: main body H, 102: sensor assembly,
103: Center metal fitting, 104: Overload protection diaphragm, 105: Main body L, 106, 107: Sealing diaphragm, 108, 109: Flange, 110, 111: Gasket, 112: Bolt, 113: Nut, 114: Connection fitting, 115 116, isolation chamber, 117, 118, measuring fluid pressure receiving chamber, 144, semiconductor differential pressure sensor, 201, first pressure receiving chamber, 202, second pressure receiving chamber, 203, first isolation chamber, 204, second Isolation room.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimi Yamamoto 882 Ma, Kataida, Ibaraki Pref. Measuring Instruments Division, Hitachi, Ltd. (56) References JP-A-6-194247 (JP, A) JP-A-4-248430 (JP, A) Table of JP-A-2-500683 (JP, A) US Patent 4,073,191 (US, A) US Patent 4,458,537 (US, A) US Patent 4,262,540 (US, A) (58) (Int.Cl. ⁷ , DB name) G01L 13/00-13/06

Claims (4)

(57) [Claims] 1. A first pressure receiving chamber for receiving a first pressure of a process fluid, a second pressure receiving chamber for receiving a second pressure of a process fluid, and a pressure applied to the first pressure receiving chamber. a first isolation chamber but transmitted, the second and the second isolation chamber applied pressure to the pressure receiving chamber is transmitted, prior Symbol first, each of the pressure transmitted to the second isolation chamber And a differential pressure sensor for detecting the differential pressure, wherein the first, second and third diaphragms are a single pressure receiving member.
Welded into recesses provided at different positions
Is, the first pressure receiving chamber, the first diaphragm is the receiving
The first diaphragm and the front
The second pressure receiving chamber is formed between the pressure receiving members , and the second diaphragm receives the pressure from the second diaphragm.
By being joined to the pressure member, the second diaphragm and the front
The first isolation chamber is formed between the pressure receiving members, and the first diaphragm is provided with the third diaphragm.
By being joined to the pressure member, the third diaphragm and the front
The second isolation chamber formed between the pressure receiving members,
Has a surface that is machined similarly to the shape of the three diaphragms
Fix the fixing bracket in the recess provided with the third diaphragm
It is formed by fitting , and furthermore, the fixing bracket is connected to the third diaphragm by pressure.
The third diaphragm is connected inside the welding position of the member.
A touching projection, and the third die
A differential pressure transmitter that is fitted with a flam . Wherein Oite to claim 1, the convex portion of the fixing bracket, is installed at the outer peripheral portion of the fixing bracket
A differential pressure transmitter characterized by being provided on a spacer provided . 3. Oite to claim 1, the recess of the pressure receiving member to which the fixing bracket is fitted, further
Fit the second fixing bracket by screw connection, and
The end face of the fixing bracket and the end face of the pressure receiving member are sealed by welding.
A differential pressure transmitter characterized by stopping . 4. Oite to claim 1, concave of the pressure-receiving member in which the first diaphragm is joined
Is processed in the same manner as the shape of the first diaphragm.
By fitting the first plug member having the
Forming a third pressure receiving chamber between the diaphragm and the plug member
And the concave portion of the pressure receiving member to which the second diaphragm is joined.
Is processed in the same manner as the shape of the second diaphragm.
By fitting the second plug member having the
Forming a fourth pressure receiving chamber between the diaphragm and the plug member
And said first and second plug member, diaphragm descriptor racer
Hole for communicating the part with the third and fourth pressure receiving chambers
Differential pressure transmitter, characterized in that it comprises a.