JP3309583B2 - Process state detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
In order to control the fluid such as gas, it measures the pressure and differential pressure of the fluid, the fluid level in the tank, etc., and relates to the process state detector used for the operation control of the whole plant. The present invention relates to a small and lightweight process state detection device that facilitates maintenance such as point adjustment.

[0002]

2. Description of the Related Art It is well known that measuring the pressure, level, and flow rate of a chemical plant is indispensable for safely and efficiently operating the plant. For this purpose, a differential pressure / pressure measuring device has been conventionally used as a process state detecting device. In the differential pressure measurement, the flow rate, density, and level can be measured. In the pressure measurement, the liquid level in a container such as a tank can be measured in addition to the positive and negative pressures. Differential pressure / pressure measuring instruments used for the above measurements may be used in an explosive atmosphere containing flammable gas or flammable substance vapor. used. In such a differential pressure / pressure measuring instrument,
As can be seen from the differential pressure / pressure oscillator shown in 4-5532, it consists of a pressure receiving part that detects differential pressure and pressure, and a signal converter that converts signals from the pressure receiving part into generalized analog and digital signals. In order to maintain the explosion-proof structure, the connection between the pressure receiving part and the signal converter has a shape and dimensions specified by standards.

FIG. 2 shows a general structure of a conventional pressure measuring instrument. In the figure, a flange 204 having a pressure application port 203 for externally applying pressure to a pressure or differential pressure sensor built in a pressure receiving section main body 202 is incorporated into a detecting section main body with a screw 205 via a gasket. In order to connect the signal of the pressure receiving section to the signal converter, a pipe-shaped joint section 207 is welded to the detection section main body 202. A connector or the like in which a signal of the sensor output is connected by a lead wire is attached to the joint.

[0004] A signal converter case 210 generally made of aluminum casting is fixed to the joint portion with screws 212. In the converter case, an indicator 215 for displaying an output signal is provided by an electronic circuit unit which incorporates electronic components for exciting the sensor, arithmetically amplifying the sensor signal, and converting the sensor signal into a generalized analog signal or digital signal. In the converter case, a cover 216 with glass for viewing an indicator for displaying an analog signal is screwed into the converter case 210.

[0005] The signal converter case 210 generally includes an amplifying section 220 for performing signal processing of a detecting section and a terminal box section 222 having a terminal plate inside for receiving power supply from the outside and sending power to the amplifier. It is composed of Further, the output signal of the detector can be viewed by incorporating an analog or digital indicator in the amplifier section 220 of the converter case 210.

An output signal is transmitted to an external host control device via a cable connected through a wiring inlet. Further, the amplifier section 22
The zero surface has an adjustment shaft hole 209 for externally adjusting the zero point of the output signal of the detector, and the zero point of the device can be changed through this shaft hole.

[0007]

As described above, in the conventional process state detecting device, the whole structure is constituted by three components, ie, a pressure receiving portion, an amplifier portion of a signal converter, and a terminal box portion. However, the size of the entire apparatus has been increased, and the structure has been complicated. Furthermore, if this detector is configured to meet the explosion-proof specifications, the size will be further increased,
It became complicated and the handling was poor. In recent years, the miniaturization of electronic components has progressed, and therefore, the detector itself has been directly mounted on the instrumentation piping by line mounting.
Regarding enforcement and maintenance in plant operation,
Miniaturization and labor saving have been desired.

When a lie-mount type is adopted to reduce the construction cost when planning a plant, it is necessary to make the detector itself sufficiently resistant to the vibration of the piping. However, because of the large size and complexity of the configuration, it was not configured to withstand these vibrations. Furthermore, if the space for installing and storing the detector is as small as possible, energy saving and material saving can be achieved in these spaces. In addition, a configuration that facilitates maintenance during maintenance of the detector is desired.

At the time of maintenance, the operator can easily adjust the zero point of the sensor even on site.
The zero-point adjustment shaft is operated. However, since this zero-point adjustment shaft is provided through the wall of the converter case, rainwater or the like flows in from the seal part, affecting the internal signal processing circuit, and reliability. Was lacking. Furthermore, since the position is fixed, depending on the installation status of the equipment,
Adjustment of the zero point became impossible, and maintenance was lacking.

[0010]

[MEANS FOR SOLVING THE PROBLEMS]
A feature of the present invention is a process for detecting the pressure of a process fluid.
And a first connector for outputting the signal of the sensor.
And a pressure receiving portion having a first connector.
And a signal for processing a signal from the sensor.
A signal processing board having a signal processing circuit;
A signal processing unit having a cylindrical housing in which a plate is stored
And the pressure receiving section and the signal processing section are substantially coaxial.
Is disposed in front of the signal processing board with respect to the pressure receiving section.
Process state detection where each housing can rotate coaxially
Wherein the signal processing board is operated by magnetism
Lead switch used as an input for zero point adjustment.
Switch is disposed, and the housing gives magnetism to an outer surface.
At least two guide grooves for inserting means for
And the guide groove is provided with the reed switch.
Arranged close to the extension on the radius of the signal processing board
That is.

[0011]

[0012]

[0013]

[0014]

[0015]

In the process state detector according to the present invention, the direction of the wiring inlet provided in the signal processing section can be easily changed from the left-right direction to the up-down direction. , And maintenance such as wiring change can be easily performed.

Further, since the pressure receiving portion, the signal processing portion, and the display of the detector are provided on substantially the same axis, the center of gravity of the detector itself is located on the same axis, so that an excessive eccentric load is not received, so that vibration is prevented. This is a configuration that can sufficiently withstand the above. Furthermore, since the signal output procedure until the signal from the sensor is output to the outside can be configured by assembling parts hierarchically according to the flow of the signal, the assemblability is excellent and the size can be reduced.

Next, the cover can be taken out of the main body while the display is kept in the cover.
Even if the display section is dropped during maintenance, the display section is protected by the cover, so that the display section is not damaged. Further, the number of steps of taking out the substrate of the signal processing circuit can be reduced, and reliability can be improved and maintenance can be reduced.

In the process state detector of the present invention, since the zero adjustment axis provided to the external device is non-mechanical, there is no need to provide any through-hole in the converter case. Reliability is improved. In addition, since the operation can be easily performed, the maintainability is excellent.
Further, the position can be changed according to the installation condition, so that it can be made compact.

Further, since the recesses of the outer body are provided in accordance with the positions where the positions of the magnetic sensors will be arranged, the positions of the magnetic sensors are adapted to the positions of the inner body and the outer body at any angle. The magnetic body is arranged as follows.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a process state detector according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of a pressure / differential pressure measuring device used as a process state detecting device according to the present invention, and FIG. 3 is a plan view taken along the line AA 'of FIG. It is shown.

The overall configuration of the pressure / differential pressure measuring device is roughly the same as that of the pressure receiving portion 1 connected to the pressure guiding pipe 102 on the low pressure side and the pressure guiding pipe 104 (not shown) on the high pressure side.
20 and a signal processing unit 190 in which a signal processing circuit for processing a signal from the sensor unit 122 is housed.

The high pressure side fluid and the low pressure side fluid pressure are applied to the pressure receiving section 120 via the high pressure side seal diaphragm 162 and the low pressure side seal diaphragm 164, respectively. ), And these pressures are transmitted to the sensor unit 1 through first and second isolation chambers 303 and 304 formed by the matrix LCD 140.
22, the semiconductor composite function sensor 4
Numeral 4 detects a pressure difference between a high pressure and a low pressure.

The signal from the semiconductor composite function sensor 44 is transmitted to the flexible printed circuit board FPC 146 and the connectors 381 and 38.
3, the circuit is transmitted to the first circuit on the first circuit board 110, further transmitted to the circuit provided on the second circuit board 112, and then to the circuit on the third circuit board 114,
The final signal information is output from the cable connected to the wiring connection port 118 as an analog constant current signal of, for example, 4 to 20 mA, or as a signal in which a square wave digital signal is superimposed on the analog constant current signal of 4 to 20 mA. Is converted to a digital constant current signal and output
Signal contents are displayed in various forms on a matrix LCD 140 which is a display unit held therein.

The high pressure side (drain pipe 194) and the low pressure side (drain pipe 196) (shown in FIG. 1) are connected to the pressure receiving section 120 so that the high pressure side and the low pressure side fluid are communicated with each other for maintenance. Is connected.

The pressure receiving section 120 has a sensor section 122, a low pressure,
High pressure side seal diaphragm 162, 164, matrix
An LCD 140, first and second pressure chambers 301 and 302, and first and second isolation chambers 303 and 304 are provided.

The pressure receiving portion 120 is formed of a single member of SUS, and holes 311, symmetrically attached to the both ends of the pressure receiving portion 120 for attaching the seal diaphragms 301, 302, respectively.
312 is provided and sealing diaphragms 301 and 3 are provided on the bottom surface.
02 is processed into the same shape as that of
Plugs 351 and 352 are attached to the entrance 2.

The seal diaphragm 1 of the pressure receiving section 120
7 above the hole 312 for attaching
As shown in (a), a tapered screw receiver for joining the pressure guiding pipe 104 is processed, and the connection adapter 2 is connected.
34 is also formed with a tapered screw receiver and is connected to the pressure guiding pipe 104 so that the pressure guiding pipe 104 is firmly connected. A taper screw receiver is formed symmetrically at a position sandwiching the receiving port for receiving the fluid from the pressure guiding pipe 104, and the connection adapter 234 is tightened to the pressure receiving section 120 by bolt screws 248, 246, so that the pressure guiding pipe 104 and the pressure receiving pipe are connected. The airtightness with the part 120 is achieved. Further, a tapered screw receiver for joining to the drain tube 194 is formed on the lower side of the hole portion 312 so that the conduction path 3 is formed.
22 connects to the hole 312.

Similarly, also in the hole 311, upper and lower portions are tapered to be connected to the pressure guiding pipe 102 and the drain pipe 192, respectively, and are connected by the conduction path 321. The taper screw receiver for receiving the pressure is processed,
Through the connection adapter 232
2 and the pressure receiving section 120 are air-tight.

A recess for accommodating the matrix LCD 140 and the sensor unit 122 is provided on the central axis of the pressure receiving unit 120 in a direction perpendicular to the seal diaphragms 162 and 164. A hole 391 for attaching the amplifier is provided on the small diameter side of the concave portion, and a hole for attaching the fixing bracket 101 for fixing the matrix LCD 140 is provided on the large diameter side.

The seal diaphragms 162, 16
4, the matrix LCD 140 and the sensor unit 122 are connected by a pressure guiding passage.

In the process state detector of this embodiment, the seal diaphragms 162 and 164 are assembled from the holes 311 and 312 of the pressure receiving section 120, and the seal diaphragm 1 is mounted.
The first and second pressure receiving chambers 301 and 302 are formed by welding so that the surfaces 62 and 164 are parallel.

Next, plugs 351 and 352 are assembled into the holes, and plugs 3
The measurement fluid pressure receiving chambers 171 and 172 are formed by joining the pressure receiving portions 51 and 352 and the pressure receiving portion 120.

In the central stepped hole of the pressure receiving part 120, a step on a cylinder is provided so as to be fixed when the sensor part 122 is inserted from the direction of the larger diameter, and the sensor part 122 is inserted therein. The conduction path of the sensor section 122 and the conduction path of the pressure receiving section 120 are assembled so as to conduct, and both ends of the sensor section 122 are welded.

Thereafter, the center fitting 151 is connected to the center fitting 1.
At the position where the conduction path 51 and the conduction path of the pressure receiving section 120 are connected, the surface processed in the same shape as the wave shape of the matrix LCD 140 is attached to the matrix LCD 140 side, and the excess load protection diaphragm 3001 is further attached to the pressure receiving section. 120 to form a first isolation chamber 304.

The center of the center bracket 151 has a matrix LC
A conduction path for transmitting pressure from the D140 to the semiconductor multifunction sensor 44 is provided, and the fixing fitting 101 is connected to the fixing fitting mounting hole so that the conduction path of the fixing fitting 101 and the conduction path of the pressure receiving unit 120 are conducted. Further, the surface processed in the same shape as the wave shape of the matrix LCD 140 is attached to the matrix LCD 140 side, metal is inserted into the groove formed by the fixing bracket 101 and the pressure receiving portion 120, metal flow bonding is performed, and the second isolation chamber is formed. Step 303 is formed.

The space surrounded by the seal diaphragm 162, the matrix LCD 140, the sensor section 122, the conduction path, and the seal bottle of the liquid sealing port is filled with a sealing liquid. Similarly, the seal diaphragm 164, the matrix LCD 140, the sensor section The space enclosed by the seal bin 122, the conduit, and the liquid sealing port is also filled with the filling liquid. As a result, in the conventional differential pressure transmitter, in order to transmit the filled liquid in the pressure receiving chamber to the isolation chamber, a pressure path must be transmitted by forming a conduction path that passes through the sensor assembly. According to the vessel, the first and second pressure receiving chambers can be respectively formed at positions near the center diaphragm, so that the amount of the sealed liquid can be reduced, and the temperature change from the process fluid can be quickly transmitted to the sensor unit 122. Thus, the semiconductor multifunction sensor 44 can detect the fluid state of the process, thereby detecting an accurate differential pressure state corrected for temperature and static pressure.

Further, in the process state detecting device of the present invention, when a transient pressure is applied, the seal diaphragm 301 or the seal diaphragm 302 receiving the excessive pressure is seated on the pressure receiving member, thereby further increasing the pressure. ,
The silicon fluid is prevented from suddenly moving, and the capacity of the silicon fluid in the pressure receiving chamber is reduced by the first or second isolation chamber 304, 30.
The absorption at 3 prevents the silicon diaphragm of the semiconductor composite function sensor 44 from being damaged.

The sensor section 122 includes the semiconductor-semiconductor composite function sensor 44 and the hermetic seal pin 145.
Alternatively, the signal of the sensor can be sent to the signal processing unit by soldering the conductor.

Since the measurement fluid pressure receiving chambers 171 and 172 are formed in the pressure receiving portion 120, unlike the conventional example, there is no need for a flange or a bolt or nut for fastening the flange. Therefore, it is possible to reduce the number of constituent members and make the overall configuration of the apparatus compact.

Further, since the process state detector of the present invention uses the semiconductor multifunction sensor 44, by applying the pressure of the process fluid to only one of the measurement fluid pressure receiving chambers 171 and 172, for example, the process line can be processed. In contrast, only the pressure guiding pipe 102 or the pressure guiding pipe 104 is connected to the pressure receiving portion to introduce the pressure fluid into the pressure receiving portion. As another example, the pressure fluid is supplied from the process tank to the measurement fluid pressure receiving chamber 171, 1
72, the other opening is sealed or the atmospheric pressure is released, so that the pressure (absolute pressure) of the process fluid or the differential pressure from the atmospheric pressure can be measured. ing.

Next, the signal processing section will be described in detail.
The signal from the sensor unit 122 is sent to the board 1 (110) and the board 2 (112) via the FPC 146 and the connector 361, and the signal is processed. 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) which are housed in the signal processing unit 190 made by aluminum die casting and are fixed to the signal processing unit 190 by screw holes 399 and fixing screws 397 provided at a 90-degree pitch. Through the signal processing unit 1
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 90.

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).

As shown in FIG. 8, the connector 383 is a connector formed of a resin having a circular joining surface with the pressure receiving portion 120, and has a hermetic seal pin 145.
A connector for outputting a signal from the FPC 146 that derives the signal is formed. The connector 383 has a screw hole 92 provided at a 90-degree pitch in the pressure receiving portion 120.
2,924,926,928 and screw 2001, respectively
It is joined in 2002, 2003 and 2004, and by changing the combination of joining of this screw hole and screw,
The connection direction of the connector 383 can be changed at a 90-degree pitch.

The connector 381 and the connector 38
4 is connected to the signal processing unit 19 as shown in FIG.
Connector insertion hole 5 provided in the shape of a cross at the bottom of
04, a predetermined position and shape are defined so that a connector holder 383 protruding so as to be in close contact with the vertical or horizontal hole of the insertion hole and the connector 381 bonded to the board can be easily inserted. At times, insertion errors are prevented.

Next, a method of configuring the zero point adjustment will be described.

As the switch for zero adjustment in the present invention, a non-mechanical switch 1121 to which the principle of an electromagnetic relay is applied is used as shown in FIG. This switch connects a pair of leads made of a magnetic material with a contact function,
This is a reed switch sealed in a glass tube so as to partially oppose it. When a magnet 909 (see FIG. 5 (b)) is moved closer or farther from the reed switch, the magnetic flux acts on the reed switch, and the reed attracts and contacts. Use the ability to move away or

The details of the embodiment of the present invention are shown in FIGS. 5A and 5B. FIG. 5A is a main partial view illustrating a zero-point adjusting unit according to the present invention. FIG. 5 (b) is a cross-sectional view of FIG.
It is the figure which showed b cross section.

The reed switches are mounted on the signal processing circuit board 112 in the signal processing section 190 in close proximity to each other. One reed switch 1121 serves as a switch for increasing the zero point, and the other reed switch 1
Reference numeral 122 denotes a switch for reducing the zero point, which is provided with different functions. This is because the reliability of the device is further ensured by a single reed switch, and the operability is simplified by simplifying the function. The reed switch is connected to the magnet 9 as described above.
09 (FIG. 5 (b)), they are arranged on the substrate 112 at a predetermined distance so as not to interfere with each other due to the strength of the residual magnetic flux of the magnet used. In addition, the surface of the case 190 has the substrate 11
Guide grooves 901 and 902 for inserting the magnet 909 are provided on the radial extension of the location where the two reed switches 1121 and 1122 are located. A magnet 909 is inserted into these guide grooves from the outside and pressed to operate the reed switch. According to this configuration, the zero point of the detector can be easily implemented without erroneous operation, and the signal processing unit 190 does not require any through-hole.
Therefore, the reliability of the airtightness can be ensured without any worries.

The signal processing unit 190 according to the state of use
And a base 112 having reed switches 1121 and 1122
In order to operate the reed switch at any position, it is desirable to provide grooves at all positions where the reed switches 1121 and 1122 will be disposed, in addition to the grooves 901 and 902. .

Further, FIGS. 6 and 7 show one embodiment in which the process state detector of the present invention is connected to a pressure guiding pipe and a cable of a two-wire transmission line, which will be described later. In addition, the position of the reed switch of the present invention can be changed according to the installation condition of the detector.

That is, as shown in FIG. 6 (a), the transmitter body is generally joined to the low-pressure and high-pressure side pressure guiding pipes 102, 104, and the wiring port 118 is parallel to the matrix LCD 140 to the left and right. Since it is located, wiring can be performed from either the left or right direction, and a desired signal is transmitted to and received from a higher-level device by a cable 702 of a two-wire transmission path. The display is oriented in the direction of the display purpose so that the operator can easily see necessary information. In the process state detector of the present invention, FIG.
As shown in (b), from the state where the cable 702 is connected to the display from the right side, in order to connect from the left side inlet, open the cap of the left side inlet, By connecting the cable lines to the + side output terminal 702 and the − side output terminal 704 in the same manner as before, the left and right connection directions can be changed. further,
Even when the wiring is connected from below or above for some reason, the bolt through hole 506 provided at the bottom of the signal processing unit 190 is connected to the screw holes 912 to 918 provided at the pressure receiving unit. +90 degrees or-
By rotating 90 degrees and changing the combination,
By changing the position of the connector insertion hole 504 through which the connector holder 383 and the connector 381 pass, the wiring direction can be arbitrarily changed while the display direction of the matrix LCD 140 is kept constant. become. As with these changes, reed switch 1
When the positions of 121 and 1122 are changed, the position of the signal processing unit 190 is kept constant and the connector holder 3 is changed.
The position of the connector insertion hole 504 through which the connector 46 and the connector 383 pass is changed at a 90-degree pitch, and the joining between the terminal plate 182 and the signal processing unit 190 is also changed at a 90-degree pitch, and the reed switch corresponding to the changed position. The reed switch can be operated by inserting the magnet 909 into any of the guide grooves 903 to 906. Further, by combining the above-described wiring direction and the display direction changing means, it is possible to simultaneously change the wiring direction, the display direction, and the position of the reed switch.

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, it is possible to change the wiring, the display direction and the position of the reed switch. So
These changes can be made while the pressure receiving portion 120 is attached to the pressure guiding pipe, so that the labor required for maintenance can be reduced as much as possible in comparison with a conventional product. Further, FIG. 7B shows FIG.
7C is an example in which the basic installation state is changed so that the wiring direction is taken from above. FIG. 7C is an example in which the display direction and the position of the reed switch are rotated by 90 degrees, and FIG. Is an example in which the display direction and the position of the reed switch are rotated by -90 degrees, and the wiring direction is changed from below. As described above, it is possible to change the wiring, the display direction, and the position of the reed switch in various ways, so that the installation space can be reduced. Further, after setting once, the plant control system is changed to change the wiring direction and the display direction. It works effectively when changing the settings to make maintenance easier.

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. 4B, the bolts 388 are passed through the bolt receiving holes 506 provided at the bottom of the signal processing unit 190 at a 90-degree pitch as shown in FIG. It is joined to the provided bolt hole 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 to be brought into contact with each other and fixed only by the minute joining 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, with reference to the concave portion 391 of the pressure receiving portion 120, the signal processing portion 190 of the converter is inserted so that the connector boulder 383 comes out of the connector insertion hole 504. 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.

Since the joint portion of the signal processing section 190 can form an explosion-proof joint surface in a concave portion provided in the pressure receiving portion, it is possible to reduce the size and material consumption. Furthermore, since the fixing method is fixed with bolts in the converter, the fastening member is not exposed, so explosion proof is convenient, environmental resistance is improved, and maintenance is improved.

Next, the integrated terminal plate is inserted into the hole 398 of the signal processing section 190 from above in a predetermined direction.
At this time, the signals from the integrated terminal plate and the pressure receiving portion are:
The connectors 383 and 381 ensure that they are firmly connected. At this time, the dimension 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 (11
0 to 112) have high rigidity, and the natural frequency does not decrease.

The signal from the pressure receiving section 120 passes through a substrate to a terminal board, and its output value is displayed on a display (matrix LCD in this embodiment) 140, or is output to a signal of a two-wire transmission line and a power supply line. Sent to the outside. Matrix LC
D140 is screwed to the signal processing unit 190 via the cover 116. The cover 116 has a matrix L
A glass or transparent member 404 is attached so that the instruction of the CD 140 can be observed from the outside, and the cover is attached to the cover by a stop spring 406 via a gasket 432 to satisfy explosion-proof specifications. Further, the cover 116 has a flange 411 of the matrix LCD 140.
It is inserted into the upper part of the unit via a pressing spring 407, and after the indicator is inserted, it is further incorporated into the cover by a stop spring 408. The matrix LCD 140 is housed in the cover 116 with some backlash. In such a configuration, the matrix LC
D140 is removable cover 116, because even when the mounting move with the cover 116, the signal processing unit cover 116 1
It will never fall off when removed from the 90.

FIGS. 6 and 7 show an embodiment in which the process state detector of the present invention is connected to a pressure guiding pipe and a cable of a two-wire transmission line.

As shown in FIG. 6A, the transmitter body is generally connected to the low-pressure and high-pressure side pressure guiding pipes 102 and 104, and the wiring ports 118 are positioned on the left and right parallel to the matrix LCD 140. Therefore, wiring can be performed from either the left or right direction, and a desired signal is transmitted to and received from a host device via a cable 702 of a two-wire transmission path. The required information is oriented in the direction of the display purpose to make it easy to see.

Then, in the process state detector of the present invention, as shown in FIG. 6B, the state in which the cable 702 is connected from the right side to the display, and the state from the inlet on the left side. To make the connection, open the cap on the left inlet, and as before, open the + side output terminal 70.
By connecting a cable line to the 2,-side output terminal 704, the left and right connection directions can be changed.

Further, even when the wiring is connected from below or above for some reason, the bolt hole 506 provided in the bottom of the signal processing section 190 is also provided.
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, and correspondingly, the connector through which the connector holder 383 and the connector 381 pass. By changing the position of the insertion hole 504, the matrix LC
The wiring direction can be arbitrarily changed while keeping the display direction of D140 constant.

When changing the display direction of the matrix LCD 140, the position of the connector insertion hole 504 through which the connector holder 346 and the connector 383 pass is changed at a 90-degree pitch while the position of the signal processing unit 190 is kept constant, and Since the connection between the terminal plate 182 and the signal processing unit 190 can be changed at a pitch of 90 degrees, the display direction can be changed even if the wiring direction is kept constant.

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

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 pressure guiding pipe, so that the labor required for maintenance can be reduced as much as possible in comparison with the conventional product.

FIG. 7B is an example in which the basic installation state of FIG. 7A is changed so that the wiring direction is taken from above.
FIG. 7C shows an example in which the display direction is rotated by 90 degrees, and FIG. 7D shows an example in which the display direction is rotated by 90 degrees and the wiring direction is changed from below. Since it is possible to change the wiring and the display direction in various ways,
The installation space can be reduced, and it works effectively when the plant control system is changed after setting once to change the wiring direction and display direction to facilitate maintenance management.

FIG. 8 shows an embodiment of a signal processing circuit of a differential pressure transmitter as a process state detecting device of the present invention. The semiconductor composite function sensor 44 outputs a change in gauge resistance due to the differential pressure, the static pressure, and the temperature as an electric signal, and is selectively taken into the multiplexer (MPX) 731.

The signals of the semiconductor composite function sensor 44 and the circuit temperature sensor taken into the multiplexer 731 are amplified by a programmable gain amplifier (PGA) 733 and then converted into digital signals by an A / D converter 734. It is transmitted to the microprocessor (MPU) 730. The memory 739 (EEPROM) stores in advance the characteristics of the differential pressure, the static pressure, and the temperature sensor (in the case of a pressure transmitter, only the characteristics of the pressure and the temperature sensor are available). The microprocessor 730 calculates a highly accurate differential pressure signal value, a static pressure and a temperature signal value by performing a correction calculation. This operation result is obtained by the D / A converter 737 and V
The signal is converted into a normal analog signal via a / I converter 738, and a differential pressure, static pressure, and temperature signal can be transmitted to a computer or a signal converter as a higher-level control device as a DC current signal of 4 to 20 mA DC. ing.

In the apparatus according to the present embodiment, information on the process status obtained from the semiconductor multifunction sensor 44 is displayed on the matrix LCD 140 in the signal processing section 190. Further, it is possible to output process information by superimposing information as a digital signal on a DC current of 4 to 20 mA DC and transmitting the digital signal by a DC current from a signal processing circuit (not shown). is there. Further, a switch 736 in the signal processing circuit is used.
Thus, the microprocessor (MPU) 730 is instructed to adjust the output of the detector, and the output is adjusted.

In a communication method in which a digital signal is superimposed on a DC current signal or 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.

FIG. 9 is a sectional view of a multifunctional differential pressure sensor used in the process state detecting device of the present invention.

The semiconductor composite function sensor 44 is an (100) plane n-type single crystal silicon, and has a circular thin portion 661 almost at the center of one surface. Thin part on this substrate
By applying a first process pressure and a second process pressure from each side of the substrate to 661, the thin portion 6
Reference numeral 61 denotes a strain generating element which responds to a differential pressure, and operates as a pressure-sensitive diaphragm for detecting a differential pressure.

On the upper surface of the differential pressure-sensitive diaphragm 661, the piezoresistance coefficient at the (100) plane becomes the maximum <1.
10> In the axial direction, the P-type resistors (gauge resistors) 631 to 634 as the first differential pressure sensors and the P-type resistors (gauge resistors) 641 to 644 as the second differential pressure sensors are respectively formed on the crystal axes. It is formed by a thermal diffusion method or an ion plantation method in a direction parallel or perpendicular to the direction. The arrangement positions of the resistors 631 to 634 and 641 to 644 are arranged in the vicinity of the fixed portion where the distortion in the radial direction and the same direction generated on the differential pressure sensitive diaphragm 661 when the differential pressure is applied becomes maximum. In addition, the arrangement direction of these resistors is 63
1 and 641 and 633 and 643 in the radial direction, 63
2 and 642 and 634 and 644 are tangential directions, and one end of each of the resistors facing the same arrangement direction is connected,
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 the thick portion other than the differential pressure sensitive 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. Thereby, the resistors 631 to 634 and 641 to 641 on the differential pressure sensitive diaphragm 661 are formed.
644 receives the distortion generated in the diaphragm and changes the resistance by the piezoresistance effect, so that the change can be extracted as a signal.

The semiconductor multifunction sensor 44 is mounted on the housing 654 via a hollow fixed base 652. The fixed base 652 is a housing 6 of the semiconductor multifunction sensor 44.
Ceramics (for example, SiC) having a linear expansion coefficient similar to that of silicon is preferable in consideration of electrical insulation with the H.54 and reduction of thermal strain due to a difference in the coefficient of linear expansion with the housing 654. At the time of material selection, the difference from the linear expansion coefficient of the silicon may be ignored. A bonding layer 650 is formed on the side of the fixing base 652 that is bonded to the semiconductor composite function sensor 44. The bonding layer 650 is the fixing base 6
The bonding surface 52 may be formed by glazing with an oxide solder such as low-melting glass, or a metal solder, or an Au—Si alloy layer or a thin film of Au may be formed by a sputtering method or a vapor deposition method. Alternatively, an organic or inorganic binder can be formed. By providing the bonding layer 650 on the bonding surface side of the semiconductor composite function sensor 44 of the fixing base 652, the semiconductor composite function sensor 44 can be easily bonded 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 semiconductor composite function sensor 44 are supplied to the lead wire 656 and the wiring board 655.
Through the terminal 145 of the hermetic seal part provided in the housing 654.

The resistors 631 to 634 and 641 to 644 on the differential pressure sensitive diaphragm 661 receive distortion generated by the differential pressure between the upper surface of the diaphragm and the concave portion 663, and the resistance changes due to the piezoresistance effect. Can be taken out. However, these resistors 6
The outputs 31 to 634 and 641 to 644 change their output even when the pressure applied to both surfaces of the differential pressure sensitive diaphragm 661 is equal (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 change in the zero point at the time of temperature change is mainly because the resistance values of the resistors 631 to 634 and 641 to 644 vary and the resistance value of the resistors is a function of the temperature. Therefore,
Since the relationship between the output 665 of the temperature sensor and the output of the differential pressure sensor is clearly related, compensation is easy. The change of the zero point when applying static pressure is mainly caused by the fixed base
Semiconductor multifunctional sensor 4 such as 652 and housing 654
It is caused by the distortion caused by the constituents other than 4. This zero point change is, like the zero point change at the time of temperature change, the zero point change of the differential pressure sensor at the time of applying the static pressure and the output 621 of the static pressure sensor.
To 624 are collected in advance as information and stored in the memory 7.
If it is stored in 39, compensation can be made 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. 11 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 a multi-drop connection is shown in the figure, it is also possible to configure the process state detecting device one-to-one with respect to the signal comparator 960.

FIG. 10 shows the display configuration of the matrix LCD 140. The display unit 810 has three display sections. The output of the detecting device displays its value, for example, a differential pressure value and an absolute pressure value in a display section 804, and a level mark 806 constituted by a dot matrix mark of the LCD corresponding to the display value of the display section 804. It is displayed like an analog graph. In addition, when the detector is out of the measurement range, the mark 8
12 is displayed, and the mark 81 is displayed when the scale is underscale.
4 is displayed. A mark indicating the attribute is displayed in the display section 816 for the signal output state of the detection device and the zero point adjustment state of the device.

FIG. 12 is an example showing a specific example of display on the matrix LCD 140 when the detection device is in the zero point adjustment state.

As the zero point adjustment state, for example, when the process state detecting device of the present invention is used as a differential pressure transmitter for periodic inspection or the like, a three-way valve connected to a pressure guiding pipe intentionally sets a zero differential pressure. Create a state and adjust it so that it is output and displayed as 0%. Also, when the process state detecting device of the present invention is used as an absolute pressure detector, for example, when it is connected to a process tank, it becomes a reference. A tank capacity water level is created and adjusted so that a signal corresponding to the water level is displayed and output.

In order to adjust the zero point of the detector at the installation location, as described above, the dedicated guide grooves 901 and 902 of the reed switch (for zero point adjustment) provided in the device.
Insert the magnet in one of the two, operate the switch, and look at the display contents of the matrix LCD 140,
Since the adjustment can be performed while checking the zero point adjustment state, maintenance and inspection can be performed easily and reliably.
Further, if the adjustment cannot be performed for some reason at the installation place of the detector, a handheld terminal 974 is connected to the two-wire transmission line to which the detector requiring the adjustment is connected, From here, the zero point adjustment start signal, the up / down signal is transmitted to the detector, and the adjustment can be advanced while checking the zero point adjustment state by looking at the display contents of the matrix LCD 140. Maintenance inspection can be performed quickly and reliably.

In the present embodiment, the reed switch is exemplified as a switch for adjusting the zero point from the outside, but it can be applied as a switch for changing the measurement span of the detector. Furthermore, it is also possible to simultaneously provide the zero point adjustment and the span adjustment in the signal processing circuit, and provide guide grooves corresponding to the positions.

[0091]

As described above, according to the process state detecting apparatus of the present invention, the equipment itself can be made very compact, which is economically advantageous, and the system can be easily replaced, and maintenance and inspection can be performed. Sometimes it is very easy to use.

Next, since the detector and the signal processing unit display are substantially on the same axis, the center of gravity of the detector itself can be configured at a symmetrical position with respect to the pressure guiding pipe, so that an excessive eccentric load is applied. Since it is not provided, the configuration can sufficiently withstand strong vibration.

At the time of maintenance, the number of steps for taking out the substrate can be reduced.

In addition, even in the maintenance of the zero point adjustment, the display of the shift direction and the level meter display move in accordance with the adjustment direction of the operator, so that the progress of the adjustment can be easily performed. Can be recognized.

In the zero point adjustment, the switch for zero point adjustment can be reliably operated regardless of the angle of the display device or the housing.

As described above, the process state detecting device of the present invention is excellent in environmental resistance, is very easy to use at the time of maintenance and inspection, and can reduce the plant operation cost. Furthermore, since the equipment itself can be configured to be stable and highly reliable, the operation efficiency of the plant can be improved, and more labor can be saved.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing the appearance of a conventional product.

FIG. 3 is a cross-sectional view of the entire detection device of FIG. 1;

FIG. 4 is an overall side view of a detection device showing an embodiment of the present invention, and a partially enlarged view of a joint portion between a signal processing unit and a pressure receiving unit.

FIG. 5 is an overall side view of a detection device and an explanatory diagram of a zero-point adjusting unit according to an embodiment of the present invention.

FIG. 6 is an example of connection of a detecting device to a pressure guiding pipe and a transmission cable.

FIG. 7 is an example of connection of a detection device to a pressure guiding pipe and a transmission cable.

FIG. 8 is a perspective view of a connection adapter from a pressure receiving unit.

FIG. 9 is a block diagram showing a signal processing system of the converter.

FIG. 10 is a sectional view showing the configuration of a semiconductor composite sensor.

FIG. 11 is an explanatory diagram of display categories of a display.

FIG. 12 is a display example of a display.

FIG. 13 is an example of a plant control system using the apparatus of the present invention.

[Explanation of symbols]

44 ... Semiconductor multifunction sensor, 101 ... Fixing bracket, 12
0: pressure receiving section, 122: sensor section, 140: matrix L
CD, 146: FPC, 151: Center bracket, 162
164: seal diaphragm, 171, 172: measuring fluid pressure receiving chamber, 190: signal processing unit, 192, 194: drain tube, 204: flange, 205: screw, 207: connection fitting, 219: zero point adjustment shaft, 232, 234 ... Connection adapters, 242, 244, 246, 248 ... bolt screws for connection adapters, 306 ... bolt screws for connection between the signal processing unit and the pressure receiving unit, 351, 352 ... plugs, 901, 90
2, 903, 904, 905, 906: guide groove, 90
9: magnet, 912, 914, 916, 918: amplifier mounting hole, 1121, 1122: reed switch, 3001: overload protection diaphragm.

Continuation of the front page (56) References JP-A-6-194247 (JP, A) JP-A-6-180263 (JP, A) JP-A 5-3962 (JP, U) JP-A 3-30842 (JP) , U) Japanese Utility Model Application 2-30036 (JP, U) Japanese Utility Model Application 1-165435 (JP, U) Japanese Utility Model Application No.61-112248 (JP, U) Japanese Utility Model Application No.61-16616 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01L 13/00-13/06

Claims (4)

(57) [Claims] 1. A sensor for detecting a pressure of a process fluid.
And a first connector for outputting a signal of the sensor
A pressure receiving portion having bets, the first of the second connector and the signal with a signal processing circuit for processing signals from the sensor for joining the connector and
A processing substrate and a cylindrical shape in which the signal processing substrate is stored.
Comprising a signal processing unit having a housing and, distribution to the signal processing unit on substantially coaxially with said pressure receiving portion
And the signal processing board and the casing with respect to the pressure receiving section.
Body in a rotatable process state detector coaxially respectively
The signal processing board is operated by magnetism and zero-point adjustment
Reed switch used as input means for
The housing is provided with a means for applying magnetism to the outer surface.
Has at least two guide grooves for
The groove is a half of the signal processing board provided with the reed switch.
A process state detector, which is arranged so as to be close on a radial extension . 2. The signal processing board according to claim 1, wherein the signal processing board and the housing are respectively provided on the pressure receiving portion.
On the other hand, a process state detector characterized in that the relative position can be rotated at a pitch of 90 ° . 3. The signal processing circuit according to claim 2, wherein the signal processing circuit has a substantially cross-sectional shape of the housing.
The reed switch is formed of a substrate having a
Process characterized by being located near the outer periphery of a plate
State detector. 4. A wiring according to claim 1, wherein a wiring for communicating with an external control device is provided on said casing.
A process state detector comprising two wiring inlets for introduction .