JPS6158712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate control device, and particularly to a pilot valve in a pilot-driven flow rate control valve.
An object of the present invention is to provide a valve that uses electrostriction of a dielectric material to drive a valve body.

Conventionally, fluid control valves for fluids such as gas have used electromagnetic force or motors. However, all of these require a large number of parts, are expensive, and consume a large amount of power.

In addition, in recent years, there has been an idea to drive valves using the electrostrictive effect of dielectric materials, and this has attracted attention as a power-saving valve because of its low drive current.However, the displacement due to electrostriction is very small, and for example, When used to control a large flow rate of fuel, etc., it was necessary to use a large dielectric material. However, since dielectric materials are generally brittle and susceptible to impact, it has been difficult to use large dielectric materials. Furthermore, pilot type solenoid valves are well known as valves that can control large flow rates with minute valve displacements. This valve is configured to control a large flow valve by the flow rate of a small pilot valve, but it is extremely difficult to control the minute flow rate flowing into the pilot valve steplessly and precisely, so it is only used as an on/off valve. It is.

The present invention achieves the following by applying a dielectric material to the pilot valve part of the above-mentioned pilot valve type control valve.
The purpose is to cover each other's shortcomings and provide a useful fluid flow rate proportional control device.

Embodiments of the present invention will be described below with reference to the drawings.

First, in Figures 1 and 2, 1 is the valve operating plate,
Ferroelectric materials 2 and 3 such as barium titanate are polarized in the direction of the arrow and are bonded together via an electrode 4, and electrodes 4' and 4'' are also attached to the surface corresponding to this bonding surface. This is what I did.

When a DC voltage 5 is applied to this valve actuating plate 1, the polarity of the applied voltage is reversed with respect to the polarization direction of the ferroelectric materials 2 and 3, so the direction of strain is opposite, and eventually the second
As shown in the figure, the entire valve operating plate 1 is curved. The degree of curvature can be freely changed by adjusting the applied voltage, and since almost no current flows, power consumption is low.

FIG. 3 shows an example in which the present invention is applied, in which a valve seat 8 is provided between a fluid inlet 6 and an outlet 7, a main valve 9 is provided opposite the valve seat 8, and the main valve 9 is normally seated by a spring 10. Pressed to 9. Further, a diaphragm 11 is connected to the main valve 9.
The diaphragm 11 constitutes a pressure regulating chamber B isolated from the fluid inlet chamber A. Reference numeral 12 denotes a small hole that communicates chambers A and B, and guides the fluid pressure in chamber A to chamber B. This small hole 12 is provided to pass through the lower case 27 and the upper case 28. 13 is chamber B and fluid outlet chamber C.
The pressure in chamber B is released to chamber C through a small hole that communicates with chamber B.
Further, the opening degree of the small hole 13 is controlled by a pilot valve 14, and the pilot valve 14 is held by an operating rod 15 formed of a dielectric material. 16 is a lead wire that supplies a voltage to be applied to the dielectric material.

Next, the operation will be explained. Now, when the pilot valve 14 closes the small hole 13, the pressure in chamber A and the pressure in chamber B are equal due to the small hole 12. Therefore, the diaphragm 11 does not operate and the main valve 9 is moved by the spring 10.
The valve seat 8 prevents the fluid from flowing from the chamber A to the chamber C. This is the closed state (the state shown in Figure 3).

Next, when voltage is applied from the lead wire 16, the first
As explained in FIG. 2, the operating rod 15 is bent in the direction to open the pilot valve 14. For this reason, room B
Since the fluid inside flows into chamber C, chamber B has a lower pressure than chamber A by the pressure drop caused by the small hole 12. As a result, fluid pressure acts on the diaphragm 11 from the chamber A side, lifting the main valve 9, and the main valve 9 comes to rest at the point where the pressure in the chamber A becomes equal to the sum of the force of the spring 10 and the pressure in the chamber B. As a result, fluid passes between the main valve 9 and the valve seat 8, and the fluid flows from the inlet 6 to the outlet 7.

The displacement of the main valve 9 is determined by the pressure in the chamber B, and the pressure in the chamber B is determined by the opening degree of the pilot valve 14. Furthermore, the opening degree of the pilot valve 14 is determined by the terminal 1.
Since it is determined by the voltage applied from 6, the flow rate of the fluid can be arbitrarily adjusted by varying this voltage. Also, since the small hole 13 is for adjusting the pressure in chamber B, there is no need to flow a large flow rate.
Since it may be very small, the amount of displacement of the pilot valve 14 may also be minute. Therefore, the displacement of the dielectric element may be small. In addition, the entire valve becomes smaller.

FIG. 4 shows an example of a circuit in which the valve shown in FIG. 3 is applied to gas combustion amount control to control the temperature at a constant level.
17 is a DC power source, and 18 is a power switch. When turned on, the power source 17 is applied to the control circuit section. 19
20 is a sensor that detects the temperature of the heated object (in this example, a negative temperature sensitive resistance element is used), and 20 is a variable resistor for temperature setting, which is connected in series with resistor 2.
1, 22, and 23 make up the bridge. Midpoints D and F of the bridge are connected to positive and negative input terminals of an operational amplifier 24, respectively. The operational amplifier 24 amplifies the potentials D and F by the ratio of the resistors 25 and 26, and outputs an output E.

Now, when the potential D=F, the potential E=E, and the operating rod 15 applies a constant opening degree to the pilot valve 14.

When the temperature of the sensor 19 is low, the resistance value is large, so the potential D becomes greater than F, and the difference in potential is amplified and the potential E also increases. Therefore, the operating rod 15 is curved greatly, and the opening degree of the pilot valve 14 is As the temperature increases, the opening degree of the main valve 9 also opens wide as described above, so the amount of gas burned increases, which works to further heat the object to be heated and bring it closer to the set value.

Next, when the temperature of the sensor 19 becomes higher than the setting, the potential D<F, the potential E decreases, and the amount of combustion is reduced. When the potential D becomes even higher, the potential E becomes almost zero, and at this time, the pilot valve 14 is closed, so the main valve is also closed, and the gas supply is stopped, so combustion is stopped.

In other words, the combustion amount is controlled so that the temperature of the heated object is always at the set value.

It should be noted that a configuration in which the dielectric element is expanded and contracted in the thrust direction instead of being curved is also possible, and the present invention can also be easily applied to this configuration. Furthermore, although an example in which the method is applied to gas combustion amount control has been explained here, it can also be applied to various other process controls.

Furthermore, although the circuit shown in Figure 4 uses a method in which the potential E is varied in a direct current manner, the same effect can be obtained by using a method in which pulse drive is performed by an oscillator and the pilot valve is turned on and off; in this case, the pulse duty ratio can be changed. can be controlled by

As explained above, in the present invention, a dielectric element for which it is difficult to obtain only minute displacements is applied to drive the pilot valve of a pilot-driven flow valve, so it is possible to control a large flow rate of fluid even with a small electrostrictive displacement. can. Furthermore, since the first small hole is provided in the wall surface constituting the fluid passage, accuracy and durability are improved.

Furthermore, since the electrostrictive displacement is small, a large dielectric body is not required, and the entire valve is constructed compactly. Additionally, the dielectric is less likely to be damaged and the reliability of the valve is improved. Note that the dielectric is mechanically weak and if the shape is large, there is a possibility that it will be damaged by a slight impact.

Furthermore, due to the characteristics of the dielectric material, only a voltage can be used for driving, and only a small amount of current is required. Therefore, power consumption is low and energy is saved. Furthermore, it has various effects such as low power consumption and can be driven by dry batteries, and is of great industrial value.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams explaining the electrostrictive effect of a dielectric, Figure 3 is a sectional view showing an embodiment of the fluid flow rate control device of the present invention, and Figure 4 is a diagram showing the fluid flow rate control device according to temperature. FIG. 2 is a circuit diagram of an embodiment when applied to combustion amount control. 6...Fluid inlet, 7...Fluid outlet, 8...
Valve seat, 9... Main valve (first valve), 10... Spring, 11... Diaphragm, 12... Small hole (first small hole), 13... Small hole (second small hole), 1
4... Pilot valve (second valve) 15... Dielectric operating rod, 19... Temperature sensor, 24... Operational amplifier, A... Fluid inlet chamber (first chamber), B...
...Pressure regulation chamber (second chamber), C...Fluid outlet chamber (third
room).

Claims (1)

[Claims] 1 The fluid flow rate is continuously adjusted by a first valve and a valve seat provided in a fluid passage having an inlet and an outlet for gas fluid, and a diaphragm connected to the first valve controls the A second chamber is provided that is isolated from the first chamber, has a spring energized in a direction that always presses the first valve against the valve seat, and further communicates the first chamber with the second chamber. a first small hole is provided in the wall surface constituting the fluid flow path;
a second small hole that communicates the chamber with a third chamber on the fluid outlet side, and a second valve that continuously adjusts the degree of opening of the first or second small hole; A fluid flow rate control device in which the second valve is driven by an operating rod made of a dielectric material.