JP3353214B2 - 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 pressure transmitter, and more particularly to a compact pressure transmitter having improved earthquake resistance.

[0002]

2. Description of the Related Art As described in Japanese Patent Laid-Open No. 60-185131 (see FIG. 2), a pressure receiving portion structure of a conventional pressure transmitter is disclosed in
The pressure receiving member is made up of parts of the main body, and seal diaphragms are fixed to both surfaces of the main body, and a sensor section is arranged between them.

[0003] Further, on both sides of the main body constituted by the main body, first and second pressure receiving chambers formed by seal diaphragms for receiving the first and second fluids are formed.
The first and second measurement chambers are provided by the sensor assembly so as to communicate with each other. In addition, these first and second
The pressure receiving chamber, the first and second measurement chambers, and the semiconductor differential pressure sensor are filled with a filling liquid.

In the conventional pressure transmitter, a flange is attached to a position facing the seal diaphragm, and the main body and the flange are tightened and fixed by bolts and nuts, thereby transmitting pressure from the process fluid to the respective pressure receiving chambers. It was like.

In maintenance of the 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. After removing the member, the seal diaphragm was inspected.

In the converter case, an electronic circuit unit incorporating an electronic component for exciting a sensor, arithmetically amplifying the sensor signal, and converting the sensor signal into a generalized analog signal or digital signal is provided. It is housed with the indicator to display, and the converter case is screwed into the converter case with a cover with glass to view the indicator to display analog signals. The converter case generally includes an amplifier unit for performing signal processing of the pressure receiving unit, and a terminal box unit having a terminal plate inside for receiving power supply from the outside and sending power to the amplifier. Further, the output signal of the detector is displayed by incorporating an analog or digital indicator in the amplifier section of the converter case.

However, in the conventional pressure transmitter as described above, the pressure receiving section, the amplifier section of the converter, and the terminal box section have three parts.
Since the detector is composed of two components, the entire detector becomes large and the structure becomes complicated.

[0008]

The conventional pressure receiving section of a pressure transmitter is composed of three components, ie, a pressure receiving section, an amplifier section of a converter, and a terminal box section. However, since the structure becomes complicated, there are problems in weight and cost, and handling is troublesome.

Furthermore, if a direct connection method with the piping of the plant is adopted in order to reduce the construction cost at the time of plant planning, the transmitter itself needs to be configured to sufficiently withstand the vibration of the piping. In the case of the detector described above, it was not possible to take sufficient countermeasures against vibration because the size and complexity of the detector were increased.

[0010]

A feature of the present invention is that a pressure receiving portion provided with a pressure sensor for measuring a difference between the pressure of a measurement fluid and the atmospheric pressure, and a signal processing circuit for processing a signal from the pressure sensor are provided. Pressure transmitter having a signal processing unit provided with
The pressure receiving section includes a first diaphragm that receives the pressure of the measurement fluid, a first conduction path that connects the first diaphragm and the pressure sensor, and a first filling path filled in the first conduction path. A sealed liquid, a second diaphragm for receiving a pressure of the atmospheric pressure, a second passage connecting the second diaphragm and the pressure sensor, and a second filling filled in the second passage. A liquid, and the first part of the housing of the pressure receiving portion.
Place the plug member on the surface on which the diaphragm is provided.
Has an introduction chamber formed by joining it to the pressure section housing.
The plug member is provided at the center of the first diaphragm.
A transparent member having at least half or more, and an outer periphery
Thread is formed on the pressure receiving part housing.
And the first diaphragm is located at a position coaxial with the signal processing circuit and the pressure sensor, and is disposed such that a surface of the first diaphragm is parallel to a surface of the pressure sensor. The second diaphragm is located at a position where an axis connecting the second diaphragm and the pressure sensor is in a direction perpendicular to an axis connecting the first diaphragm and the pressure sensor, and a surface of the second diaphragm. Are arranged at right angles to the surface of the pressure sensor.

Still further, a pressure receiving section having a pressure sensor for measuring a difference between the pressure of the measurement fluid and the reference pressure, and a signal processing section having a signal processing circuit for processing a signal from the pressure sensor. In the transmitter, in the housing of the pressure receiving unit, a diaphragm that receives pressure of the measurement fluid, and a conduction path that connects the diaphragm and one end surface of the pressure sensor,
A reference pressure space is formed between a surface of the pressure sensor that does not face the conduction path and the pressure-receiving section housing, the enclosure including the filled liquid filled in the conduction path and the pressure- receiving section casing; The above
Place the plug member on the surface on which the diaphragm is provided.
Has an introduction chamber formed by joining it to the pressure section housing.
The plug member is provided at the center of the first diaphragm.
A transparent member having at least half or more, and an outer periphery
Thread is formed on the pressure receiving part housing.
And the diaphragm is located at a position coaxial with the signal processing circuit and the pressure sensor, and is arranged such that the surface of the diaphragm is parallel to the surface of the pressure sensor, and the reference pressure space is , In a vacuum state.

[0012]

[0013]

[0014]

In the pressure transmitter according to the present invention, since the first diaphragm, the pressure sensor, and the signal processing section are arranged on the same axis, the first diaphragm constituted by the first diaphragm is provided.
Can be configured as short as possible between the pressure receiving chamber and the signal processing unit, and because it is arranged on the same axis, the center of gravity of the transmitter is on that axis, so excessive vibration was applied Even in this case, the bias force is not generated, and the measurement can be always stabilized. In addition, when the first and second seal diaphragms are provided in the main body housing, the seal diaphragms are provided so that the pressure receiving directions of the seal diaphragms are different from each other. Since the first and second pressure receiving chambers can be provided close to each other, the path of the pressure guide path in which each pressure chamber is provided can be shortened. Therefore, the amount of the sealed liquid stored in each path can be reduced. Can be reduced, the detection response can be speeded up, and the size of the entire housing can be reduced.

Further, in the process state detector of the present invention, the direction of the wiring introduction port provided in the signal processing unit is set as follows.
Since it can be easily changed from the left and right direction to the up and down direction, and the display direction can be changed similarly,
Maintenance such as wiring change can be easily performed while the entire detector is compact.

[0016]

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

FIG. 1 is a sectional view of an embodiment of the pressure transmitter of the present invention. FIG. 3 is a detailed view of the pressure receiving member 20 shown in FIG. 1, and FIG. FIG. 3 shows an aa ′ cross-sectional view.

This pressure transmitter mainly comprises a sensor unit 12
2, the first and second seal diaphragms 140, 162,
A pressure receiving member 120 having first and second pressure receiving chambers 304 and 301 and first and second measuring chambers 303 and 352;
The signal processing unit 190 that processes a signal from the sensor unit group 122 includes a signal processing unit 190.

The pressure receiving member 120 is formed of a single member made of SUS.
Hole 1 for mounting the seal diaphragm 162 of FIG.
A member 35 for fixing and sealing the seal diaphragm is provided at the entrance of the hole 21 at the bottom thereof.
The hole processing 338 for inserting 2 is performed.

On the other hand, a hole 322 for mounting the first seal diaphragm 140 is provided on the other surface of the pressure receiving member 120, and the seal diaphragm 1 is provided on the bottom surface thereof.
A member 151 processed in the same shape as the shape of 40 is provided, and holes 321 and 310 are provided coaxially. The hole 310 has a screw hole 337 having a diameter larger than that of the seal diaphragm 140 for fixing the stopper 101.

The pressure receiving member 120 is formed with a tapered screw 352 on the upper side of the hole 321 for mounting the seal diaphragm 140 and a tapered screw 353 on the lower side, respectively. Is connected to On the other hand, a hole 171 provided for attaching and fixing the second seal diaphragm 162 is used to protect the diaphragm on its coaxial extension and to insert a member 171 for introducing a reference pressure. Holes are machined.

A stepped hole 323 for accommodating the sensor unit 122 and a first pressure receiving chamber are formed coaxially with the first sealer diaphragm 140 of the pressure receiving member 120.
A hole 322 for inserting a center fitting 151 for preventing deformation of the diaphragm is provided. Stepped hole 323
A hole 309 for mounting with the amplifier is on the small diameter side of
A hole 310 for fixing the plug 101 is provided on the large diameter side.

Then, the sealing diaphragms 140, 16
2. The sensor units 122 are connected by the conductive paths 352 and 311.

The structure of the first pressure receiving chamber 304 and the second pressure receiving chamber 301 in the pressure transmitter according to one embodiment of the present invention will be described with reference to FIG.

[0025] In the pressure transmitter of this embodiment, incorporating the hole 3 38 from the second sealing diaphragm 162 of the pressure receiving member 1 20, and insert the member 1 71 as the surface of the sealing diaphragm 162 is parallel Then, bonding and sealing are performed by metal flow (plastic processing) to form a pressure receiving chamber 301 . Further, a member 322 for protecting the second seal diaphragm and for introducing a reference pressure is inserted into an extension hole 338 on the coaxial extension, and joined and sealed by a metal flow (plastic working) to perform the reference pressure. A chamber 171 is formed.

The central stepped hole 323 of the pressure receiving member 120
, The sensor assembly 122 is inserted from the direction with the larger diameter,
Conducting path 352 of sensor unit 122 and pressure receiving member 120
Of the sensor unit 122 is welded.

Thereafter, the center fitting 151 is connected to the center fitting 1.
51 and the conducting path 35 of the pressure receiving member 120
A first measuring chamber 303 is formed with the attached sensor unit group 122 at a position where the second conductive member 2 is conducted. Further, the first seal diaphragm 140 is coaxially disposed with the pressure receiving member 120.
To form a first pressure receiving chamber 304 with the center fitting 151.

A conduction path 172 for transmitting pressure to the semiconductor sensor 44 is provided at the center of the center fitting 151. Also, on the same axis as the first sealer diaphragm 140, the fixing part 1 is attached to the screw part 337 of the fixing part mounting hole 310.
01 is screwed in, the end faces are joined by welding and sealed,
The first pressure guiding chamber 152 is formed.

The space surrounded by the seal diaphragm 140, the sensor assembly 122, the conduction path 172, and the seal pin 164 of the liquid seal port is filled with a non-stretchable liquid silicone oil as a first filling liquid. Similarly, the seal diaphragm 162, the sensor unit 122, and the conduction path 311
The space surrounded by the seal bottle 165 serving as a liquid sealing port is filled with silicone oil as a second filling liquid.

In the amplifier mounting hole 309, the amplifier case 8
No. 0 connection part 392 is inserted and fixed to pressure receiving member 120 with bolt 306 in pressure receiving member 120 and amplifier case 80. The pressure detecting operation of the 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 140, the pressure of the measurement fluid is transmitted to the first sealed liquid in the first pressure receiving chamber 304 on the back side of the seal diaphragm 140 via the seal diaphragm 140. Further, this pressure is applied to the center bracket 151.
Is transmitted to the semiconductor sensor 44 through the pressure guiding path 172.

The reference pressure (atmospheric pressure) is transmitted to the second seal diaphragm 162 through the hole 352 of the diaphragm cover 171, and the reference pressure (atmospheric pressure) is applied to the second sealed liquid in the second pressure receiving chamber 301. ) Is transmitted, and this pressure is transmitted to the back surface of the sensor 44 by the conduction path 311. As described above, the semiconductor sensor 44 detects the pressure difference between the pressure of the measurement fluid transmitted to the surface and the reference pressure (atmospheric pressure),
The output of the semiconductor sensor 44 is the hermetic seal pin 14
5 to the atmosphere open side, and is transmitted to a signal processing unit (amplifier) via the FPC 146.

Further, even if the seal diaphragm 140 is joined to the center fitting 151 and the silicon oil in the first pressure receiving chamber 304 moves to the first measuring chamber 303, the first diaphragm of the sensor 44 is prevented from being damaged. Measurement room 3
By setting the capacity of 03, even when an excessive pressure of the process fluid is applied, the center fitting 151 operates to stop the operation of the seal diaphragm 140, and the diaphragm of the sensor 44 is not damaged.

Further, the capacity of the second measuring chamber 352 is configured to be able to absorb the silicon fluid in the second pressure receiving chamber 301 even when an excessive pressure is applied to the second pressure receiving chamber 301 in an emergency. Accordingly, even when an excessive pressure is applied to the second seal diaphragm 162 in an emergency, the movement of the seal diaphragm is stopped by the wall formed in the same shape as the seal diaphragm of the second pressure receiving chamber 301. Will not be damaged.

Since the measurement flow guide chamber 152 is formed in the pressure receiving member 120, there is no need for a flange or a bolt or nut for fastening the flange, unlike the conventional example. That is, the stopper 101 is used to form the measurement flow guiding chamber 152.
Only need to be provided. The method of fixing the plug 101 is as follows.
The joints are joined by screw portions 337 provided in the 20 recessed holes, and the end faces are welded to be sealed.

According to the pressure transmitter having the above-described configuration, the pressure receiving direction of the second seal diaphragm 162 on the pressure reference chamber side is arranged in a direction perpendicular to the pressure receiving direction of the sensor unit 122. Compared with the conventional example in which the diaphragm and the pressure receiving member 120 are welded to each other in a position where strain is not transmitted as compared with the conventional example in which the diaphragm is arranged on the same axis, the zero point does not change and the pressure can be accurately measured. .

On the other hand, since the measurement flow pressure guiding chamber 152 can be formed in the pressure receiving member 120 on the first sealer diaphragm 140 side, the pressure receiving member 120 can be formed as a single component, and the measurement flow pressure guiding chamber 152 can be formed. No flanges, bolts, or nuts are required to form. Therefore, the shape change of the pressure receiving member 120 due to the tightening of the bolts and nuts and the measurement flow pressure chamber 1
Since there is no deformation of the pressure receiving member main body when an excessive pressure is applied to 52, there is no change in the zero point of the seal diaphragm, and the pressure can be measured more accurately. Further, the first seal diaphragm 140 and the sensor unit 12
2 is coaxially arranged, and a distance is secured between the diaphragm and the center fitting 151 forming the first pressure receiving chamber, so that the influence of distortion due to welding or the like can be sufficiently reduced. Also, when the pressure transmitter is used, if a pressure exceeding the specification is applied to the first seal diaphragm 140 under some conditions, the pressure sensor 44 is broken,
The seal diaphragm comes into contact with the corrugated portion having exactly the same shape as the first sealer diaphragm provided on the first sealer diaphragm side of the center fitting 151 and is not further deformed, so that the seal diaphragm is broken. In the event of a failure, there is no leakage of the sealed liquid inside and no influence on the process fluid.

As shown in FIG. 4, the process pipe 350 is screwed after a silicon tape is wound around the pipe 350 at the connection port of the pressure receiving member 120. A drain / vent plug 355 is attached to the other connection port of the pressure receiving member 120, and the connection between the process pipe and the drain / vent plug 355 can be connected both up and down.

The sensor unit 122 includes the semiconductor composite function sensor 44 and the hermetic seal bin 145, and the FPC 146 is soldered to the atmospheric pressure release side of the hermetic seal bin 145, so that the sensor necessary for the conventional pressure transmitter is used. A hole for extracting a signal is formed in the pressure receiving member 120.
To eliminate the need to provide

In the amplifier mounting hole 309, the amplifier case 1
90, the pressure receiving member 120 and the amplifier case 19
0, insert the joint 392 into the joint formed by
At 383, the amplifier case 190 is fixed to the pressure receiving member 120 inside the amplifier.

FIG. 5 shows an embodiment of a signal processing circuit of a differential pressure transmitter as a process state detecting device of the present invention. The multifunction sensor 44 outputs a change in gauge resistance due to the differential pressure, the static pressure, and the temperature as an electric signal, and outputs the signal to the multiplexer (M
PX) 731.

The signals of the multi-function type sensor 44 and the circuit temperature sensor taken into the multiplexer 731 are amplified by a programmable gain amplifier (PGA) 733 and then amplified by an A / A
The signal is converted into a digital signal by the D converter 734 and transmitted to the microprocessor (MPU) 730. Memory 73
9 (EEPROM) pre-stores the differential pressure, static pressure, and temperature sensor characteristics (in the case of a pressure transmitter, only the differential pressure and temperature sensor characteristics, or only the static pressure and temperature sensor characteristics). The microprocessor 730 corrects and calculates a differential pressure signal value, a static pressure and a temperature signal value by using these data. This calculation result is converted into a normal analog signal via a D / A converter 737 and a V / I converter 738, and is converted into a DC current signal of 4 to 20 mA DC, which is then transmitted to a higher-level control device, such as a computer or signal converter. The pressure, static pressure and temperature signals can be transmitted.

In the apparatus of this embodiment, the multi-function sensor 44
The information on the process state obtained from the
90 on the display unit 140. Furthermore, DC4
It is possible to output process information by superimposing information as a digital signal on a DC current of の 20 mA and sending it, and by sending a digital signal based on the DC current from a signal processing circuit (not shown).

In a communication method in which a digital signal is superimposed on a DC current signal, or in a communication method in which a digital signal is used to communicate with an external monitoring and control device, the digital I / O converter 738 includes a digital I / O converter. By the / O circuit,
For example, as shown in FIG.
72 or the hand-held terminal 974, information about the process status is displayed, and from these devices, parameters such as measurement ranges can be set, changed, output adjusted, input / output monitored, and self-diagnosis can be specified.

Next, the signal processing section will be described in detail.
The signal from the sensor unit 122 is transmitted to the FPC 146 and the connector 361.
The signals are sent to the substrate 1 (110) and the substrate 2 (112) via the. Further, a power supply for driving these substrates is a SUS that constitutes the converter 80.
Alternatively, the terminal plate 182 and the substrate 3 (114) are accommodated in the signal processing unit 190 made of aluminum die-cast, and are fixed to the signal processing unit 190 with screw holes 399 and fixing screws 397 provided at a 90-degree pitch. Through the signal processing unit 19
The power is supplied from an external power supply via a two-wire transmission line from a wiring connection port 118 provided at a symmetrical position in 0.

These boards are first soldered to the board 3 (114) via connection pins 382 provided on the terminal board, and then the boards 1 and 2 are sequentially connected to the connector 132 provided on each board. , 134, 136, and 138, are assembled hierarchically. Therefore, in such a configuration, the terminal plate and the substrates 1, 2, 3 are integrated concentrically on the axis of the terminal plate. For this reason, these units can be collectively managed, for example, as a board assembly, an amplifier unit, or the like, so that it is possible to assemble very easily and reduce man-hours. These substrates are fixed by a substrate holder 395 joined to the terminal plate 182 when mounted in the case. Since the substrate holder 395 has a spring property on the outer peripheral surface, the substrate holder 395 is completely adhered to the hole 398 of the case, so that there is no play. Therefore, the vibration resistance of the whole amplifier unit is improved.

The substrate 1 (110) includes the pressure receiving section 1
The connector 381 is provided to enable signal connection with the connector 383 (FPC146).
And a connector connected to the connector).

The connector 383 is, as shown in FIG.
A hermetic seal pin 14 is a connector formed of a resin having a circular joining surface with the pressure receiving portion 120.
5, a connector for outputting a signal from the FPC 146 for extracting the signal of No. 5 is formed. The connector 383 has screw holes 922, 924, 926, and 928 provided at a 90-degree pitch in the pressure receiving portion 120, and a screw 9 respectively.
02, 904, 906, and 908. By changing the combination of the screw hole and the screw, the connector 383 can change the joining direction at a 90-degree pitch.

The connector 381 and the connector 38
As shown in FIG. 7, the connection with No. 3 protrudes from a connector insertion hole 504 provided in the shape of a cross at the bottom of the signal processing unit 190 so as to be in close contact with the vertical or horizontal hole of the insertion hole. The predetermined position and shape are defined so that the connector boulder 383 and the connector 381 joined to the board can be easily inserted, and insertion errors do not occur at the time of connection.

Next, a method of joining the signal processing section and the pressure receiving section will be described.

The signal processing section 190 is connected by a joining surface section 392 of the signal processing section 190 formed so as to conform to the outer dimensions of the circular concave section 391 of the pressure receiving section 120, and is arranged in four circumferential directions. As shown in FIG. 10, the bolt is connected to the bottom of the signal processing unit 190 by bolts 388 through bolt through holes 506 provided at 90-degree pitches.
It is joined to bolt holes provided at a 90-degree pitch in the pressure receiving portion shown at 0 and fixed to the pressure receiving portion 120 with a predetermined tightening torque.

Further, at the time of this fixing, the pressure receiving portion 120 and the case 80 are configured so as to be brought into contact with each other only by the minute joint surface 393 provided on the case 80. For this reason, excessive force and partial contact do not occur at the cylindrical joints (391 and 392), and the gap required for explosion-proof performance is always maintained. Further, even when a large vibration is applied to the converter, the gap of the cylindrical portion is always kept constant, so that there is no backlash and the natural frequency of the signal processing unit 190 does not decrease. For this reason, according to the permanent joining method, it can be normally used sufficiently even in a place having a severe frequency (for example, about 150 Hz, 3G class).

Next, an assembling procedure up to assembling the terminal plate (including the substrate) into the case 80 will be described.

First, the signal processing unit 190 of the converter is inserted so that the connector boulder 383 comes out of the connector insertion hole 504 with reference to the concave portion 391 of the pressure receiving unit 120. Next, a 90-degree pitch bolt through hole 506 at the bottom of the converter and screw holes 912 to 918 of the same pitch provided in the concave portion of the pressure receiving portion are matched, and after setting in a predetermined direction, The signal processing unit 190 is fastened to the detector with the bolt 388 from the upper part of the case.

As a result, the joint portion of the signal processing section 190 can form an explosion-proof joint surface in the concave portion provided in the pressure receiving portion, so that compactness and material saving can be achieved. Furthermore, since the fixing method is fixed with bolts in the converter, it is completely explosion-proof that the fastening member is exposed, the environment resistance is improved, and the maintainability is improved.

Next, the integrated terminal plate is inserted 398 into the hole of the signal processing section 190 from above in a predetermined direction (for example, the direction shown by the arrow in FIG. 6). At this time, signals from the integrated terminal plate and the pressure receiving portion are transmitted to the connector 38.
The connection between the connector and the contact surface of the terminal board is determined by a predetermined dimension, and the dimensions are configured to be slightly pressed. Thereby, the substrates 1 and 2 (110 to 112)
Has a high rigidity and its natural frequency does not decrease.

The signal from the pressure receiving section 120 passes through the substrate to the terminal plate, and the output value is displayed on a display (dot matrix LC).
D) Displayed at 140, or transmitted to the outside through a signal on a two-wire transmission line and a power supply line. The display 140 is screwed to the signal processing unit 190 via the cover 116. Glass or a transparent member 404 is attached to the cover 116 so that the indication on the display 140 can be observed from the outside. In addition, in order to satisfy the explosion-proof specifications, a stop spring 406 is provided via a gasket 432. Attached to the cover. The cover 116 further includes an indicator 140
After the indicator is inserted into the upper part of the collar portion 411 via the presser spring 407, the stop spring 408 is further inserted.
Is incorporated into the cover. The display 140 is
It is housed in the cover 116 with some backlash. In such a configuration, the display 140
Moves together with the cover 116 even when the cover 116 is attached or detached or attached, so that the cover never falls off even when the cover is removed from the signal processing unit 190.

FIG. 6 is a plan view showing a state where the cover is detached, and FIG. 9 is a perspective view showing the detached state. The display device 140 is formed integrally with a total of four terminals 421 for electrical connection and guide pins 422 for positioning at the time of mounting, and a cover portion having a concave shape to protect them. 423. Thus, even when the cover is removed, the electrical connection terminals 421 are not exposed, and the reliability is sufficiently ensured. When the cover 116 is mounted on the signal processing unit 190, the cover 116 may be connected to the connection portion 521 on the receiving side of the terminal plate 182 already housed in the signal processing unit 190 and the guide pin insertion hole 522. Is screwed into the signal processing unit 190. Display 140 is cover 1
16 is held with a certain amount of space, so it can be rotated inside the cover, but by inserting the guide pins and terminals and then tightening, the display is turned The cover can be tightened. In addition, as the mounting progresses, the display 1
The stop 40 comes into contact with the surface of the terminal plate and stops while pressing the collar 411 of the display with the pressing spring 407. At this time, spacers are formed in the terminal plate 182 and the display 116,
In this space, electric wires of a two-wire transmission line for transmitting and receiving power distribution signals from outside are stored.

FIGS. 7, 8, and 9 show an embodiment in which the pressure transmitter of the present invention is connected to a process pipe and a cable of a two-wire transmission line.

As shown in FIG. 7, the transmitter main body is generally in a state of being joined to the process pipe 104, and a wiring port 118 is provided.
Are located in the left and right directions in parallel with the display 140, so that wiring can be performed from either the left or right direction.
A target signal is transmitted / received to / from a higher-level device through a cable 702 of a wire transmission line.
Reference numeral 40 is directed to a display direction in which the operator can easily view necessary information.

In the process state detector according to the present invention, the cable 70 is located from the right side with respect to the display.
In order to connect from the left inlet from the state where 2 has been connected, open the cap of the left inlet and connect a cable line to the + output terminal 702 and the − output terminal 704 as before. By connecting, the left and right connection directions can be changed.

Further, even if the wiring is connected from below or above for some reason, the bolt through hole 506 provided at the bottom of the signal processing section 190 is kept connected to the process pipe 104. The connector holder 383 is rotated by +90 degrees or -90 degrees with respect to the screw holes 912 to 918 provided in the pressure receiving portion to change the combination thereof.
Also, by changing the position of the connector insertion hole 504 through which the connector 381 passes, the wiring direction can be arbitrarily changed while the display direction of the display device 140 is kept constant.

When the display direction of the display 140 is changed, the position of the signal processing unit 190 is kept constant,
By changing the position of the connector insertion hole 504 through which the connector holder 346 and the connector 383 pass at a 90-degree pitch, and also changing the joining between the terminal plate 182 and the signal processing unit 190 at a 90-degree pitch, the wiring direction is kept constant. It is possible to change it as it is.

Further, by combining the above-described wiring direction and display direction changing means, the wiring direction and the display direction can be changed simultaneously or individually by 90 degrees.

In the process state detector of the present invention, by changing the relative position combination of the pressure receiving section 120 and the signal processing section 190, the wiring and the display direction can be changed. These changes can be made while the part 120 is attached to the process pipe, so that the labor required for maintenance can be reduced as much as possible in comparison with a conventional product.

For this reason, the wiring and the display direction can be variously changed, so that the installation space can be reduced. Further, once the setting is made, the plant control system is changed to change the wiring direction and the display direction. Effectively works for easy maintenance.

As described above, according to the pressure transmitter of the present invention, the terminal plates 810 and 820, the terminal plate 830, and the display 8
Since 01 is installed concentrically on the axis of the converter case 90, the signal processing unit can be made compact with a single configuration. Therefore, the pressure receiving section and the signal processing section can be arranged on one axis, and the pressure receiving direction of the differential pressure sensor and the first diaphragm are arranged on the same axis, and the signal processing section has a symmetrical structure. The parts are also arranged coaxially, so even if high vibrations occur in the entire pressure transmitter, it is possible to suppress the generation of oscillating force, so it is possible to measure high-precision pressure even in a bad vibration environment Will be possible.

Further, since the connection port with the process pipe is provided coaxially with the structural members having the symmetrical structure as described above, the pressure transmitter of the present invention generates an oscillating force against vibration from the process pipe. Therefore, the vibration of the entire pressure transmitter including the process piping can be reduced.

Further, by arranging the pressure receiving direction of the seal diaphragm at right angles to the pressure receiving directions of the first and second seal diaphragms, the welded portion between the center diaphragm and the pressure receiving member 20 is coaxially arranged. Can be provided at a location where distortion is not transmitted, as compared with the conventional example in which the seal diaphragm is arranged, so that distortion does not occur in the shape and position of the seal diaphragm.

Then, the first seal diaphragm is arranged on the first end face with respect to the housing of the pressure receiving section,
The second seal diaphragm is arranged on the other end face having a different degree direction, and further arranged so that the pressure receiving direction of the sensor comes coaxially with the pressure receiving direction of the first seal diaphragm, and the first seal diaphragm is placed. Since the signal of the sensor is taken out from the third end face opposing the first end face, the path of the sealed liquid from the first and second pressure receiving chambers to the sensor can be formed as short as possible. Can be minimized, and expansion of the sealed liquid due to a temperature change can be minimized. In addition, since the signal extraction path from the sensor to the signal processing unit can be minimized, the signal processing unit can be formed closest to the sensor, so that the entire pressure transmitter can be formed compactly. It has a configuration that has the least temperature influence on the signal extraction path to the part and is excellent in vibration resistance.

Further, even if an excessive pressure is applied from the process fluid to the first and second pressure receiving chambers 304 and 301 due to the arrangement in the perpendicular direction, the distortion of the members generated in the vicinity of the respective seal diaphragms is mutually distorted. Since it is difficult for the seal diaphragm to be transmitted, there is no change in the zero point or the change in the support of each seal diaphragm, and the pressure can be accurately measured. In addition, by arranging the seal diaphragms in the right-angle direction, as shown in FIG. The diaphragm of the pressure sensor is held by a hollow support member whose end is joined to the frame, so distortion transmitted to the diaphragm of the pressure sensor located in the center of the housing is reduced, improving measurement accuracy I do.

FIG. 11 is a sectional view of a multifunctional differential pressure sensor used in the process state detecting device of the present invention.

The multi-function type differential pressure sensor chip 44 is (10
The n-type single-crystal silicon of the 0) plane has a circular thin portion 661 almost at the center of one plane. By applying the first process pressure and the second process pressure from the respective surfaces of the substrate to the thin portion 661 on the substrate, the thin portion 661 becomes a strain-generating body sensitive to the differential pressure. It operates as a pressure-sensitive diaphragm.

On the upper surface of the differential pressure-sensitive diaphragm 661, the piezoresistance coefficient at the (100) plane becomes maximum <1.
10> In the axial direction, P-type resistors (gauge resistors) 631 to 634 which are differential pressure sensors are formed by a thermal diffusion method or an ion plantation method in a direction parallel or perpendicular to the crystal axis, respectively. The position of each of the resistors 631 to 634 is determined by the differential pressure sensitive diaphragm 661 when a differential pressure is applied.
It is placed in the vicinity of the fixed part where the distortion occurring in the radial direction and the same direction generated above is the maximum. The directions in which the resistors are arranged are 631 and 633 in the radial direction, and 632 and 63
4 is a tangential direction, one end of each resistor facing the same arrangement direction is connected, and the other end of each resistor is connected to a detection terminal to form a bridge circuit.

Further, resistors 621 to 624 which are sensitive to static pressure are formed on a thick portion other than the differential pressure sensing diaphragm.
By connecting these to a bridge circuit, a large static pressure signal can be obtained. In addition, a temperature-sensitive resistor 665 is formed in the thick portion, and the change in the resistance value is taken out from an output terminal, so that the temperature of the process fluid can be measured indirectly.

Then, the thickness of the shape of the differential pressure sensitive diaphragm 661 is set to a desired shape and thickness according to the differential pressure to be sensed, and is formed by anisotropic wet etching or dry etching. Accordingly, the resistors 631 to 634 on the differential pressure sensitive diaphragm 661 receive distortion generated in the diaphragm, and the resistance changes due to the piezoresistance effect, so that the change can be extracted as a signal.

The multi-function type differential pressure sensor chip 44 is mounted on the housing 654 via a hollow fixed base 652. The fixing base 652 is electrically insulated from the housing 654 of the multi-function type differential pressure sensor chip 44 and the housing 654.
Ceramics (for example, SiC) whose linear expansion coefficient is similar to that of silicon is desirable in consideration of the reduction of thermal strain due to the difference in linear expansion coefficient from that of silicon. The difference from the expansion coefficient may be ignored. A bonding layer 650 is formed on the fixing table 652 on the bonding surface side with the sensor chip 44. The bonding layer 650 is formed by glazing the bonding surface of the fixing base 652 with an oxide solder such as low-melting glass, or a metal solder,
Alternatively, an Au—Si alloy layer or a thin film of Au can be formed by a sputtering method or an evaporation method. Alternatively, an organic or inorganic binder can be formed. By providing such a bonding layer 650 on the bonding surface side of the sensor chip 44 of the fixing base 652, the sensor chip 44
Can be easily joined at a low temperature. Further, since the bonding layer is thin, the influence of the bonding strain can be reduced as much as possible.

The differential pressure, static pressure, and temperature signals from the multi-function type differential pressure sensor chip 44 are transmitted to the outside via terminals 145 of a hermetic seal portion provided on the housing 654 via the lead wire 656 and the wiring board 655. Each is taken out.

Incidentally, the resistors 631 to 634 on the differential pressure sensitive diaphragm 661 are connected to the upper surface of the diaphragm and the concave portion 6.
Since the resistance is changed by the piezoresistance effect due to the distortion generated by the differential pressure of 63, the signal can be taken out. However, these resistors 631 to 634 operate when the pressure applied to both surfaces of the differential pressure sensitive diaphragm 661 is equal.
The output changes even in (static pressure state) or in response to a change in temperature. The former output change is called a zero point change due to static pressure, and the latter output change is called a zero point change due to a temperature change. The zero point change at the time of temperature change is mainly caused by the resistor 631
This is because the variation of each resistance value of ６ to 634 and the resistance value of the resistor are functions of temperature. Therefore, the relationship between the output 665 of the temperature sensor and the output of the differential pressure sensor is clearly related, and compensation is easy. The change in the zero point when the static pressure is applied is mainly caused by the fixed base 652 generated when the static pressure is applied.
It is caused by distortion generated by components other than the sensor chip 44 such as the housing and the housing 654. As with the zero point change at the time of the temperature change, the relationship between the zero point change of the differential pressure sensor at the time of applying the static pressure and the outputs 621 to 624 of the static pressure sensor is previously collected as information and stored in the memory 739. If you do, you can compensate based on this information. For this reason, highly accurate compensation is possible, including variations in the amount of liquid sealed in the detector, and variations in the seal diaphragm and the center diaphragm.

FIG. 16 shows an embodiment of a process control system in which the process state detecting device of the present invention is connected to a host device for monitoring and controlling the process state.

The process state signals detected by the process state detectors (differential pressure transmitters or absolute pressure transmitters) 952 and 954 connected to the two-wire transmission line 950 in a multidrop manner are transmitted via a signal comparator 960. By connecting to the operator's console 970, the process status can be known even at a location remote from the process site. It is also possible to instruct the operator's console 970 to set parameters such as the measurement range of the process state detector, adjust output, output a self-diagnosis result of the detector, etc., and output the result. is there. Further, with the handheld terminal 974 connected to the two-wire transmission line 950, commands equivalent to those of the operator's console and the results can be obtained from the detection device.

Further, although an example of the multi-drop connection is shown in the figure, the process state detecting device may be configured one-to-one with respect to the signal comparator 960.

Another embodiment of the pressure transmitter according to the present invention will be described with reference to the drawings.

The pressure transmitter shown in FIG. 12 is substantially the same as the transmitter shown in FIG. 1 except that the method of joining the plug 101 and the pressure receiving section 120 is changed.

[0084] and a member 101 having a Flip ne greater taper than the diameter of the external diameter of the sealing diaphragm 140 is provided, digits set a tapered thread 123 of the pressure receiving member 120 the same diameter at the same time configuration of the plug in this example.

[0085] The member 101 is screwed through the silicon tape to the pressure receiving member 120, the process fluid and the atmospheric pressure comes to be sealed by the junction of this. The member 101 is formed with a hexagonal concave portion 102 at the center portion, and is screwed with a predetermined torque using a fastener.

According to such a configuration, the member 101 can be detached from the pressure receiving member 120 due to the screw connection, and therefore, when the seal diaphragm 140 is periodically inspected, the diaphragm surface is directly observed. Therefore, maintainability of the transmitter is further improved.

According to the pressure transmitter of the present invention, since the process pipe 104 is directly connected to the pressure receiving member 120, the pressure transmitter is connected to the pressure pipe in order to inspect the seal diaphragm like a conventional pressure transmitter. It is not necessary to remove the flange and disassemble the flange, and the seal diaphragm can be inspected while the pressure transmitter is directly connected to the process pipe.

The pressure transmitter shown in FIG. 13 is substantially the same as the transmitter shown in FIG. 1 except that a transparent member 135 is provided on the stopper 101.

In this example, a transparent member 135 having at least half the diameter of the seal diaphragm 140 is disposed at the center of the plug 101, and the transparent member 135 is attached to the plug 10
1, and a member 135 is attached to the stopper via a seal member 136 and hermetically sealed.

As a method for sealing the transparent member 135 to the stopper 101, the sealing member 136 is used to seal the stopper
For example, copper , aluminum, or the like is used as a member having excellent ductility according to (1), and it is possible to bond and seal by metal flow, which is a type of plastic working method.

Further, even when the pressure of the process fluid is applied to the measuring chamber, a compressive force is applied to the transparent member 135 at the time of joining by the joining of the metal flow.
Even if the fluid pressure is applied, this pressure is only partially released, and no problem occurs in strength. Also, member 1
The mounting of the pressure receiving member 1 is carried out by screw connection as in FIG.
20 can be attached.

According to such a configuration, the seal diaphragm 140 can be constantly inspected via the transparent member in a state where the pressure transmitter is connected to the process pipe, so that the work which occurs at the time of maintenance inspection can be reduced. Therefore, the maintainability is further improved, and the stability of the equipment itself can be checked at all times, so that the stability of the whole plant is further improved.

FIG. 14 shows an example in which the pressure transmitter of the present invention is applied to a diaphragm replacer type used for measuring the pressure and liquid level in a tank in process instrumentation.

The conventional pressure transmitter of this diaphragm replacer type has a configuration in which a component for transmitting the pressure from the diaphragm replacer portion is added to the flange 205 in a configuration substantially the same as the configuration of the transmitter of FIG. It has become.

For this reason, according to the conventional diaphragm replacer type pressure transmitter, when the transmission component is attached to the flange, it must be joined without fail, and the distortion at this time affects the configuration of the entire transmitter. Therefore, the characteristics have changed. Further, since the components are always joined to the flange, the cost has been increased by the components.

As shown in FIG. 14, in the pressure receiving portion of the present invention, the shape of the plug 101 is changed, and a pressure guiding passage for enabling pressure transmission from the diaphragm replacer is formed in the pressure receiving member 1.
20.

The stopper 101 has a pressure guiding passage 123 on the outer periphery thereof, and further has a space for forming a pressure guiding chamber 302 on a surface facing a first pressure receiving chamber 304 formed by the first seal diaphragm 140 and the pressure receiving member 120. The space and the pressure guiding passage 123 secure a communication path by cutting a member in the plug 101. And the plug 101
Is hermetically attached to the pressure receiving member 120 as described above.

A pressure guiding path 354 for transmitting the pressure of the diaphragm replacer type process to the pressure guiding path 123 is provided on the side opposite to the second seal diaphragm 162. Further, a component 3 for connecting the diaphragm replacer section and the pressure receiving member on the extension of the pressure guide path.
55 are joined and sealed by welding.

Therefore, the third closed fluid silicon fluid, which is not seen in the above-described pressure detector, is sealed in the space closed by the diaphragm replacer, the pressure introducing passage 354, and the seal diaphragm 140. Accordingly, even if the diaphragm replacer portion is made airtight due to, for example, inadequate welding of the connection component member 355, the effect is not spread to the silicon fluid in the first and second sealed spaces, so that repair is performed. Then, the silicon fluid is sealed in the third closed space again, so that the function as the diaphragm replacer type can be maintained.

According to such a configuration, the stopper 10
1 by changing the shape of the second seal diaphragm 162.
The pressure transmitter can be changed to a remote replanar type pressure transmitter simply by providing a pressure guide path on the opposite side of the pressure transmitter. Can be

Further, since the first seal diaphragm 140 and the connecting member 355 of the diaphragm replacer are formed on different surfaces of the housing, no joint distortion is transmitted to the seal diaphragm 140, so that the detection accuracy is improved. Will be able to

Further, according to the diaphragm replacer type pressure transmitter of the present invention, the pressure guiding chamber 302 can be formed coaxially with the pressure sensor, the seal diaphragm, and the signal processing section, so that high vibration can be obtained. When the pressure transmitter of the present invention is installed in a place where the pressure is generated, the biased vibration does not occur, so that the vibration to the sensor can be reduced and the pressure can be measured with high accuracy.

[0103]

[0104]

[0105]

The pressure transmitter shown in FIG. 15 shows an absolute pressure transmitter in which the reference pressure is an absolute pressure type in a configuration substantially the same as that of the transmitter shown in FIG.

FIG. 15 shows the construction of the absolute pressure transmitter according to the present invention.
This will be described with reference to FIG.

In this absolute pressure transmitter, the pressure receiving section 1
20 is configured so that the atmospheric pressure reference chamber shown in the pressure transmitter of FIG. As the vacuum reference chamber, the second measurement chamber 352 in the sensor unit 122 is a vacuum reference chamber. This reference chamber is a pressure detection sensor 4
When joining 4 to a fixed base, it is joined and formed simultaneously so as to be in a vacuum state. For this reason, the second pressure receiving chamber as shown in FIG. 1 becomes unnecessary. Therefore, the formation of the hole 171 communicating passage 311 in the pressure receiving member 120 becomes unnecessary, and the second seal diaphragm becomes unnecessary. The passage 80
Reference numerals 6,808 denote test holes provided for checking the airtightness of the joint during assembly, and 808 and 804 denote pins for sealing after the end of the test.

[0109] With this configuration, simply abolishing the hole of the reference chamber side of the member 120, since it changes the pressure receiving portion of the absolute pressure pressure transmitter, is necessary to newly equipped with additional parts together is extensible And more economical.

Further, in this absolute pressure transmitter, a pressure receiving chamber containing a silicon fluid is formed coaxially with a differential pressure sensor, a seal diaphragm, and a signal processing section, and another pressure receiving chamber is formed in an off-axis portion. There is no need to construct a pressure chamber in which the silicon fluid is contained, and the vibration resistance is significantly improved as compared with a reference pressure type pressure transmitter.

[0111]

According to the pressure transmitter of the present invention, when the seal 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 seal diaphragm. Has no effect. Therefore, there is an effect that an accurate pressure can be detected, and the entire transmitter can be reduced in size. Further, even if the pressure detection sensor is damaged by an excessive pressure, the seal diaphragm is not damaged, so that the sealed liquid does not leak and the reliability is improved. 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.

Further, according to the pressure transmitter of the present invention,
The equipment itself can be made very compact, and it is excellent in environmental resistance and economical, but it is also very easy to use for maintenance and inspection, reducing plant implementation costs. Becomes Further, since the equipment itself is stable and the reliability can be improved, the operation efficiency of the plant can be improved, and more labor saving can be achieved.

Further, the pressure receiving portion and the amplifier can be ignited even in a flammable gas by inserting the junction portion of the amplifier into a concave portion provided in the pressure receiving portion and tightening from the inside of the converter. Since the sexual joint is not exposed to the outside, it does not ignite.

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

[0115] Since the measurement 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 was conventionally required is eliminated and the pressure transmitter is provided. Inspection of the diaphragm is simplified.

Further, regarding the configuration of the pressure receiving portion and the amplifier, the configuration in which the amplifier and the pressure receiving portion are provided on one axis makes it possible to improve the vibration resistance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an entire detection device showing one embodiment of the present invention.

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

FIG. 3 is a cross-sectional view of the pressure receiving unit of FIG.

FIG. 4 is a sectional view taken along the line aa ′ of FIG. 3;

FIG. 5 is a block diagram showing a signal processing flow of the amplifier of the present invention.

FIG. 6 is a cross-sectional view illustrating a function of attaching and detaching the signal processing unit cover.

FIG. 7 is a cross-sectional view illustrating connection between a signal processing unit and a pressure receiving unit.

FIG. 8 is a connection example of a pressure transmitter to a process pipe and a transmission cable.

FIG. 9 is a perspective view of the joint between the signal processing unit cover and the case.

FIG. 10 is a perspective view of a connection adapter from a pressure receiving unit.

FIG. 11 is a sectional view showing a configuration of a semiconductor composite sensor.

FIG. 12 is a cross-sectional view of another embodiment in which an opening is screwed.

FIG. 13 is a cross-sectional view of another embodiment in which an opening is screwed.

FIG. 14 is a cross-sectional view of another embodiment in which an opening is screwed.

FIG. 15 is a configuration sectional view of an absolute pressure transmitter according to another embodiment of the present invention.

FIG. 16 shows an example of a plant control system using the apparatus of the present invention.

[Explanation of symbols]

120: pressure receiving section, 190: signal processing section, 192, 194
... Drain tube, 232,234 ... Connection adapter, 24
2, 244, 246, 248: bolt screws for connection adapter; 306: bolt screws for connection between the signal processing unit and the pressure receiving unit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-238236 (JP, A) JP-A-6-194247 (JP, A) JP-A 5-69649 (JP, U) JP-A 61-194 50241 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 13/00-13/06

Claims (2)

(57) [Claims] 1. A pressure transmitter having a pressure receiving portion provided with a pressure sensor for measuring a difference between the pressure of a measurement fluid and the atmospheric pressure, and a signal processing portion provided with a signal processing circuit for processing a signal from the pressure sensor. In the pressure receiving unit, a first diaphragm that receives the pressure of the measurement fluid, a first conduction path that connects the first diaphragm and the pressure sensor, and a first filling path that fills the first conduction path. 1, a second diaphragm for receiving a pressure of atmospheric pressure, a second conduction path connecting the second diaphragm and the pressure sensor, and a second filled in the second conduction path. Wherein the first diaphragm of the housing of the pressure receiving section is provided.
Joining the plug member to the pressure receiving unit housing
Having an introduction chamber formed by the first diaphragm, and the stopper member is provided with a small portion of the first diaphragm at a central portion.
At least half of the transparent member has
A thread is formed and screwed into the pressure receiving unit housing
Therefore, the first diaphragm is joined so as to be coaxial with the signal processing circuit and the pressure sensor, and is arranged such that the surface of the first diaphragm is parallel to the surface of the pressure sensor. The second diaphragm is located at a position where an axis connecting the second diaphragm and the pressure sensor is perpendicular to an axis connecting the first diaphragm and the pressure sensor, and the surface of the second diaphragm is A pressure transmitter arranged so as to be perpendicular to the surface of the pressure sensor. 2. A pressure transmitter having a pressure receiving portion provided with a pressure sensor for measuring a difference between a pressure of a measurement fluid and a reference pressure, and a signal processing portion provided with a signal processing circuit for processing a signal from the pressure sensor. In the housing of the pressure receiving portion, a diaphragm that receives the pressure of the measurement fluid, a conduction path that connects the diaphragm and one end surface of the pressure sensor, and a sealed liquid that is filled in the conduction path. A reference pressure space is formed between a surface of the pressure sensor where the conduction path does not face and the pressure receiving unit housing, and a surface of the pressure receiving unit housing on which the diaphragm is provided.
On the other hand, by joining the plug member to the pressure receiving unit housing,
And the plug member has a small central portion of the first diaphragm.
At least half of the transparent member has
A thread is formed and screwed into the pressure receiving unit housing
Therefore, the diaphragm is located at a position that is coaxial with the signal processing circuit and the pressure sensor, and is arranged such that the surface of the diaphragm is parallel to the surface of the pressure sensor. A pressure transmitter characterized by being in a vacuum state.