JPH0361828A - Pressure sensor and fluid feeder - Google Patents

Abstract

PURPOSE:To simplify compensation of temperature by a method wherein current for maintaining an operating body at a constant position against applied pressure of a diaphragm is applied to an actuator while pressure is detected from the current value. CONSTITUTION:When pressure fluid is led into a chamber 7 from an input 7a of a pressure detector 4, a diaphragm 6 is subjected to the pressure so that an operating body 8 is to move upward together with the diaphragm 6 by a distance proportional to the applied pressure. A plunger 10 contacting the operating body 8 moves upward together with the operating body 8 so that the position of its tip is to be changed. On the other hand, a position sensor 17 always detects the position of the tip of the plunger 10 and outputs the detected signals to a control circuit 18. If force for moving the operating body 8 is generated, the circuit 18 supplies current to a coil 11 of an actuator so as to generate force against the above force. This current value and the force generated by the actuator are in proportional relation so that secondary pressure can be calculated from the current value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to gas combustion systems, etc., and reduces the pressure of pressure fluid supplied from a fluid supply source to the working pressure at the final use part and supplies it. The present invention relates to a fluid supply device and a pressure detector used in the fluid supply device.

[Prior Art] Generally, when a fluid is used, the high-pressure fluid supplied from a fluid supply source is not used as it is, but is used after being reduced to the operating pressure at the final use part4.
In a gas combustion system, a governor is installed between the gas supply source and the final use part, the burner, which operates mechanically based on the pressure balance between the two to maintain a constant secondary pressure even if the primary pressure changes. is installed. Further, the pipe line is equipped with a pressure detector to detect pressure abnormalities and the like. The pressure detector includes one using a semiconductor pressure sensor, and a device that uses a diaphragm and detects pressure by detecting the amount of movement of the diaphragm.

Furthermore, in order to be able to control the secondary pressure, there is a device in which a proportional solenoid is provided above the governor so that the secondary pressure of the governor can be controlled in proportion to the current value applied to the proportional solenoid.

[Problems to be Solved by the Invention] However, the characteristics of conventional semiconductor pressure sensors change greatly depending on temperature, and some change in the positive direction while others change in the negative direction, making temperature correction difficult. Ta. on the other hand,
Pressure detectors that use a diaphragm detect pressure from the amount of movement of the diaphragm due to pressure changes, so when pressure changes are large, the pressure sensor becomes large and requires a large installation space to allow for that movement. There's a problem. On the other hand, when a proportional solenoid is attached to the governor to control the secondary pressure, if the flow rate range of the pressure fluid, that is, the changing range of the secondary pressure is widened, the characteristics of the governor will change, and control at low pressure will be affected. The problem is that it can't be done. Furthermore, since the secondary pressure is backed up purely mechanically, vibrations become large depending on the load conditions, resulting in poor stability and noise. Furthermore, there was also the problem of secondary pressure drift due to the temperature characteristics of the proportional solenoid and diaphragm.

The present invention has been made in view of the above problems, and includes:
The first object is to provide a pressure detector using a diaphragm that is easy to perform temperature correction, can be adapted to various measurement ranges, and can be miniaturized. A second object is to provide a fluid supply device capable of stably and accurately controlling secondary pressure regardless of load conditions.

[Means for Solving the Problem] In order to achieve the first object, in the pressure detector according to the first aspect, the pressure of the pressure fluid supplied from the fluid supply source is provided in the middle of the pipe line. a housing that is connected to a pipe line of a fluid supply device that reduces the pressure to a predetermined pressure with a flow rate regulating valve and supplies the fluid to an end use part, and into which the reduced pressure fluid is introduced;
a diaphragm provided in the housing; an actuator attached to the diaphragm and movable integrally with the diaphragm in proportion to the pressure received by the diaphragm;
a position detection sensor that detects the position of the actuating body; an actuator that generates a force that resists the pressure received by the diaphragm to act on the actuating body; and a current that maintains the position of the actuating body constant. A control circuit is provided which outputs a signal corresponding to the current value applied to the actuator.

Further, in order to achieve the second object, in the invention described in the second fi1 claim, the pressure of the pressure fluid supplied from the fluid supply source is reduced to a predetermined pressure by a flow rate regulating valve provided in the middle of the pipe. In the fluid supply device that supplies the fluid to the final use part,
A housing into which the fluid after pressure reduction is introduced into the pipe line downstream of the flow rate adjustment valve, a diaphragm provided in the housing, and a diaphragm attached to the diaphragm and integrated with the diaphragm in proportion to the pressure received by the diaphragm. a position detection sensor that detects the position of the actuating body; an actuator that generates a force that resists the pressure received by the diaphragm and acts on the actuating body; A pressure detector equipped with a control circuit that applies a current to the actuator to keep it constant and outputs a signal corresponding to the current value is connected, and the detection signal of the pressure detector is fed back to the actuator. A control section was provided to control the flow rate adjustment valve.

[Function] In the pressure detector according to the first claim, the fluid pressure after pressure reduction (secondary pressure) acts on the diaphragm, and the actuating body moves integrally with the diaphragm in proportion to the pressure received by the diaphragm. However, a current is applied to the actuator to hold the actuating body at a constant position against the pressure received by the diaphragm, and the actuating body is held at a constant position. Then, pressure is detected from the current value.

Further, in the fluid supply device according to the second aspect, the secondary pressure detected from the pressure detector connected to the pipeline downstream from the flow rate adjustment valve is fed back to a control unit that controls the flow rate adjustment valve. , the flow rate regulating valve is controlled so that the secondary pressure becomes a predetermined pressure.

[Embodiment 1] Hereinafter, an embodiment in which the present invention is embodied in a gas combustion system will be described with reference to FIGS. 1 to 4. As shown in Figure 2,
In the middle of the pipe #12, one end of which is connected to a fluid supply source (not shown) and the other end of which is connected to the burner 1 as the end-use part, there is a pipe in which the pressure of the pressure fluid supplied via the pipe line 2 is connected to the burner. 1
A flow rate regulating valve 3 is disposed to reduce the pressure to a predetermined pressure (secondary pressure) when used in. A pressure detector 4 is connected between the flow rate regulating valve 3 and the burner 1 to detect secondary pressure.

As shown in FIG. 1, the pressure detector 4 has a housing 5 with an open top and a diaphragm 6 disposed in the upper part of the chamber 7.
is formed in the chamber 7, and an inlet lower a is formed in the chamber 7 through which the fluid after being depressurized is introduced. An actuating body 8 is fixed to the diaphragm 6 so as to be linearly movable integrally with the diaphragm 6 in proportion to the pressure received by the diaphragm 6, that is, the pressure inside the chamber 7. An actuator 9 is installed in the upper part of the housing 5 to generate a force that resists the pressure received by the diaphragm 6 and to act on the actuating body 8.

The actuator 9 has a moving coil type configuration,
One langeer 10, in which a coil 11 is wound around a cylindrical coil winding portion 10a, is connected to a casing 12 of an actuator 9.
The actuating member 8 is disposed at the center thereof so as to be slidable along its axial direction (vertical direction in FIG. 1), and its base end is placed in contact with the tip of the actuating body 8. Further, a permanent magnet 9a is disposed outside the coil winding portion 10a.

The upper surface of the pressure receiver 6a of the diaphragm 6 and the casing 12
A set spring 13 is interposed between the lower part of the holder and the lower part of the holder. Further, an adjustment screw 14 is screwed onto the bottom of the housing 5, and a cancel spring 16 is interposed between the diaphragm 6 and a spring receiver 15 fixed to the tip of the adjustment screw 14. A position detection sensor 17 that detects the position of the actuating body 8 by detecting the tip position of the plunger 10 is disposed above the casing 12. The zero position detection sensor 17 may include a differential transformer, an optical sensor, a magnetic The output signal of the zero position detection sensor 17, which uses a known sensor, ultrasonic sensor, etc., is output to a control circuit 18 that controls the amount of current applied to the coil 11 of the actuator 9, and the control circuit 18 detects the position. Based on the detection signal from the detection sensor 17, a current of a magnitude that maintains the position of the plunger 10 at a constant position is applied to the coil 11.

On the other hand, as shown in FIG. 3, the flow rate regulating valve 3 for regulating the secondary pressure uses a proportional valve whose valve body 20 is operated by a proportional solenoid 19. The valve body 20 is a fluid passage 21
A valve seat 2 provided between an inlet 21a and an outlet 21b of
The valve body 20 is movably arranged between a closed position in which it contacts the valve seat 22 and an open position in which it is separated from the valve seat 22, by a spring 24 interposed between the bottom surface of the casing 23 and the lower surface of the valve body 20. The elastic body 20a is urged in a direction in which the upper end contacts the lower end of the plunger 25 and the elastic body 20a contacts the valve seat 22. The proportional solenoid 19 is controlled by a control unit 26, which inputs a signal corresponding to the secondary pressure value output from the control circuit 18 of the pressure detector 4, and sets it as the detected secondary pressure value. The coil 19a of the proportional solenoid 19 is
It is designed to control the amount of electricity supplied to the

Next, the operation of the apparatus configured as described above will be explained. The pressure of the pressure fluid supplied from the fluid supply source through the pipe line 2 is changed to a predetermined secondary pressure by the flow rate regulating valve 3 and then supplied to the burner 1 . Pressure fluid is introduced into the pressure detector 4 connected between the flow rate regulating valve 3 and the burner 1 from the input lower a. When pressurized fluid is introduced into the chamber 7 from the inlet lower a, the diaphragm 6 receives the pressure, and the actuating body 8 together with the diaphragm 6 tends to move upward in FIG. 1 by a distance proportional to the received pressure. Then, the plunger 10 that comes into contact with the actuating body 8 moves upward together with the actuating body 8, and the position of its tip portion tends to change. On the other hand, the position detection sensor 17 constantly detects the position of the tip of the plunger 10 and outputs the detection signal to the control circuit 18, and the control circuit 18 moves the actuating body 8 when the diaphragm 6 receives secondary pressure. When a force is generated, the coil 1 of the actuator 9 is configured to generate a force that resists the force.
Supply current to 1.

The pressure received by the diaphragm 6 and the secondary pressure in the chamber 7 are in a proportional relationship as shown in FIG.
There is generally a proportional relationship between the current value applied to the coil 11 and the force generated in the actuator 9 as shown by the solid line in FIG. 4(b). Therefore, when secondary pressure acts on the diaphragm 6, the coil 11 is used to hold the actuating body 8 in a fixed position.
The secondary pressure is determined from the magnitude of the current value supplied to the secondary pressure.

Even if the characteristics of the actuator 9 are not in a linear relationship as shown by the dotted line in FIG. 4(b), the secondary pressure can be determined from the current value supplied to the coil 11 by examining the characteristics in advance. The relationship between the pressure received by the diaphragm 6 and the pressure inside the chamber 7 varies depending on the diameter or material of the diaphragm 6, and various ranges can be accommodated by selecting the diameter or material.

On the other hand, the control unit FI@ts outputs a signal informing the current value supplied to the coil 11 to the control unit 26, and the control unit 26 compares the signal with a preset value corresponding to the secondary pressure. , when the signal value from the control circuit 18 differs from the set value, the current value applied to the proportional solenoid 19 is adjusted so as to adjust the opening degree of the valve body 20 of the flow rate regulating valve 3 in a direction that makes the difference zero. change. Therefore, the secondary pressure at the predetermined location to which the pressure detector 4 is connected is controlled to be the set pressure regardless of the load state.

[Embodiment 2] Next, another embodiment of the pressure detector 4 will be described with reference to FIG. The pressure sensor 4 of this embodiment differs from the previous embodiments in that a non-sliding type actuator 9 is used. The inside of the housing 5 is divided into two chambers 7.27 by a diaphragm 6, with an upper chamber 2.
7 is communicated with the outside via a balance hole 27a.

In the chamber 27, a permanent magnet 29 is fixed to a support 28 fixed to the upper part of the actuating body 8. A permanent magnet 30 is also fixed to the lower end of the operating body 8. A position detection sensor 17 made of a Hall element is arranged on the outside of the housing 5 at a position corresponding to the actuating body 8. Further, the actuator 9 uses a proportional solenoid 32 having an iron core 31 fixedly arranged at its center, that is, at a position facing the permanent magnet 29. When the coil 33 is energized, a magnetic force that repels the permanent magnet 29 is generated, and a force that resists the force received by the diaphragm 6 is applied to the actuating body 8.

In the pressure detector 4 of this embodiment as well, when pressure fluid is introduced into the chamber 7, the diaphragm 6 tends to move upward in FIG. The distance between the permanent magnet 30 fixed to the lower end of the position detection sensor 17 is about to change. A current is supplied to the coil 33 so as to resist the force of the actuating body 8, prevent the movement of the actuating body 8, and maintain a constant distance between the permanent magnet 30 and the position detection sensor 17. Since the magnitude of the magnetic force, that is, the force acting on the actuating body 8 changes in accordance with the current value supplied to the coil 33, the secondary pressure can be determined from the current value. Furthermore, since there is no sliding part in this embodiment, durability is improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may, for example, use a structure other than the above-described configuration as the flow rate regulating valve 3, or may be applied to a structure other than a gas combustion system.

[Effects of the Invention] As detailed above, in the pressure detector according to the first claim, temperature correction is easily performed, and even when the pressure measurement range is wide, the detector does not become large, and furthermore, By selecting the diameter or material of the diaphragm, various measurement pressure ranges can be accommodated.

Further, in the invention as set forth in claim 2, the secondary pressure at the required location can be controlled accurately and stably regardless of the load condition.

[Brief explanation of drawings]

Figures 1 to 4 show the first embodiment, in which Figure 1 is a sectional view of the pressure detector, Figure 2 is a block diagram, Figure 3 is a sectional view of the flow rate adjustment valve, and Figure 4 ( a) is a diagram showing the relationship between the secondary pressure and the pressure received by the diaphragm, Figure 4 (b) is a diagram showing the relationship between the force generated by the actuator and the current value, and Figure 5 is the second example of actual noodles. FIG.

Claims (1)

[Claims] 1. The pressure of the pressure fluid supplied from the fluid supply source is
2) is connected to the pipe line (2) of the fluid supply device that reduces the pressure to a predetermined pressure using the flow rate regulating valve (3) provided in the middle of the section (2), and supplies the fluid to the final use section (1), where the reduced pressure fluid is introduced. a housing (5), a diaphragm (6) provided in the housing (5), and a diaphragm (6) attached to the diaphragm (6) and integrated with the diaphragm (6) in proportion to the pressure received by the diaphragm (6). an actuating body (8) that is movable, and a position detection sensor (1) that detects the position of the actuating body (8).
7), an actuator (9) that generates a force against the pressure received by the diaphragm (6) and acts on the actuator (8), and an actuator (9) that maintains the position of the actuator (8) constant. a control circuit (18) that applies a current to the actuator (9) and outputs a signal corresponding to the current value;
A pressure detector characterized by being provided with. 2. The pressure of the pressure fluid supplied from the fluid supply source is transferred to the pipe (
In a fluid supply device that reduces the pressure to a predetermined pressure with a flow rate adjustment valve (3) provided in the middle of the flow rate adjustment valve (3) and supplies it to the final use part (1), 2)
A housing (5) into which the fluid after depressurization is introduced, a diaphragm (6) provided in the housing (5), and a diaphragm (6) attached to the diaphragm (6) and proportional to the pressure received by the diaphragm (6). an actuating body (8) that is movable integrally with the diaphragm (6); a position detection sensor (17) that detects the position of the actuating body (8); An actuator (9) that generates force to act on the actuating body (8), and applying a current to the actuator (9) that maintains the position of the actuating body (8) constant and corresponding to the current value. A pressure detector (4) equipped with a control circuit (18) that outputs a signal is connected, and the detection signal of the pressure detector (4) is fed back to control the flow rate regulating valve (3). A fluid supply device provided with a control section (26).