JPH02146380A - Fluid control valve - Google Patents

Abstract

PURPOSE:To prevent explosion caused by the discharge of a piezoelectric body from being carried to a flow passage chamber, by making the division of the flow passage chamber having a valve body which opens/closes a flow passage between an entrance and an exit, and a drive chamber having a piezoelectric body which drives the valve body, by means of an explosion prevention heat absorbing member. CONSTITUTION:In the case of a unimorph piezoelectric element 27 not being subjected to the condition of electrification, combustible gas which has entered from an entrance 11, does not flow to an exit 12 side by means of a valve body 22 which has been pushed to a valve seat 20 by a spring 21. When voltage is impressed, the tip of the piezoelectric element 27 opens the valve body 22 and gas flows to the exit 12. When air invades the inside of a fluid control valve 37 under the condition of a flow passage chamber 18 and a drive chamber 19 being filled with combustible gas, and a crack or the like is generated at a ceramic 26 under the density condition of gas being in the range of being able to be exploded, electric discharge occurs at a crack portion and gas explodes. But, the heat of explosion is absorbed by means of an explosion prevention heat absorbing member 17, so the temperature of a blast toward the flow passage chamber 18 from a shaft hole 24 lowers and the explosion of the flow passage chamber 18 is not realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an explosion-proofing means for a fluid control valve that controls a flow rate by utilizing a change in displacement of a voltage body, and an explosion-proof heat absorbing member of this explosion-proofing means.

2. Description of the Related Art Conventionally, this type of fluid control valve has been disclosed, for example, in Japanese Patent Application Laid-Open No. 63-834.
As shown in Publication No. 73, it had a structure as shown in Fig. 7. In other words, there is a fixing member 2 inside the valve case 1.
A piezoelectric deflection element 3 is provided which is fixed at one end by a screw. A valve body 5 for opening and closing the fluid outlet nozzle 4 is attached to the other end of the piezoelectric deflection element 3. The piezoelectric deflection element 3 is constructed by pasting piezoelectric plates 7 on both sides of a metal substrate 6. 8 is a fluid inlet boat, and 9 is a lead wire for supplying electricity to the piezoelectric deflection element 3.

Problems to be Solved by the Invention However, in a fluid control valve in which such a piezoelectric deflection element 3 is provided in the valve case 1 through which fluid passes, it is difficult in practice to control combustible gas that has the risk of explosion. . In other words, in the piezoelectric deflection element 3, the piezoelectric plate 7, which is the electrode surface to which voltage is applied, was exposed. Therefore, if a shock is applied to the fluid control valve while a voltage is applied to the piezoelectric flexible element 3 and the piezoelectric plate 7 is cracked, an electric discharge will occur on the surface of the piezoelectric plate 7 and the flammable gas in the fluid control valve will explode. Not only will the fluid control valve be destroyed, but in the worst case scenario, the piping connected to the fluid control valve and equipment after the fluid control valve may also explode and be destroyed.

Therefore, even if a discharge occurs in the piezoelectric deflection element, the present invention suppresses the explosion to a narrow area near the piezoelectric deflection element, thereby preventing the explosion and destruction of the fluid control valve, the piping connected to the fluid control valve, and the equipment after the fluid control valve. The primary purpose is to prevent

The second purpose is to obtain an explosion-proof heat absorbing member that is inexpensive and has a large explosion-proof effect.

The third object is to obtain an explosion-proof heat absorbing member that is electrically safe and has a large explosion-proof effect even when used near a piezoelectric bending element to which a high voltage is applied.

The fourth purpose is to obtain an explosion-proof heat absorbing plate shape that will most efficiently obtain the explosion-proof effect.

Means for Solving the Problems In order to achieve the above-mentioned first object, the present invention provides an explosion-proof structure for a flow passage chamber containing a valve body that opens and closes a flow passage, and a drive chamber containing a piezoelectric body that drives the valve body. It is divided by heat absorbing members.

In order to achieve the second object, the present invention comprises an explosion-proof heat absorbing member made of a metal plate.

Furthermore, in order to achieve the third object, the present invention comprises an explosion-proof heat absorbing member made of a non-conductive heat absorbing body.

Furthermore, in order to achieve the fourth object, the present invention comprises unevenness means on the surface of the explosion-proof heat absorbing member.

Operation The fluid control valve of the present invention has the above-described configuration, so that even if a discharge occurs on the surface of the piezoelectric body provided in the drive chamber and a combustible gas that can explode explodes, the explosion-proof heat absorbing member absorbs the thermal energy at the time of the explosion. Therefore, the explosion is not propagated to the flow path chamber side, and as a result, the fluid control valve is not destroyed.

The explosion-proof heat absorbing member made of a metal plate has good thermal conductivity, so it efficiently absorbs thermal energy during an explosion.

Furthermore, an explosion-proof heat absorbing member made of a non-conductive heat absorbing member is electrically safe when used near a piezoelectric body to which a high voltage is applied, and absorbs thermal energy well in the event of an explosion.

Furthermore, the explosion-proof heat absorbing member having the unevenness means can have a large heat absorbing area within a limited area.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings. In FIGS. 1, 2, and 3, reference numeral 10 denotes a valve vertebral body having a fluid inlet 11 and an outlet 12, and a valve body upper part 14 is attached to the valve body 10 via a seal packing 13 with a screw 1.
The fluid control valve case 16 is fixed by the valve 5 to prevent leakage of the fluid flowing therein. The inside of the fluid control valve case 16 is divided into a flow path chamber 18 and a drive chamber 19 by an explosion-proof heat absorbing member 17 made of a stainless steel plate or an aluminum plate. A valve body 22 is provided in the flow path chamber 18 and is in contact with a valve seat 20 and biased by a spring 21 . The valve body 22 is provided with a valve shaft 23, which penetrates into the drive chamber 19 side without contacting the shaft hole 24 of the explosion-proof heat absorbing member 17.

On the other hand, in the drive chamber 19, a unimorph piezoelectric element 27, which is a piezoelectric body in which a metal plate 25 and a ceramic 26 are bonded, is fixed to the valve frame body 10 with screws 30 via a fixing member 29 having a sealing material 28. This unimorph piezoelectric element 27
A guide 32 having a recess 31 that contacts the valve shaft 23 is provided at the tip. The tip end 33 of the valve shaft 23 that comes into contact with the recess 31 has a hemispherical shape and is in point contact with the lower surface 34 of the recess 31 .

Further, even when the tip end 33 of the valve shaft 23 is in contact with the recess 31 and shifted from side to side, the valve shaft 23 is configured not to contact the shaft hole 24 of the explosion-proof heat absorbing member 17. 35 is a lead wire to the unimorph piezoelectric element;
6 is an electrical terminal. The fluid control valve 37 is configured with such a configuration.

Next, the operation of the configuration of this embodiment will be explained. Normally, when the unimorph piezoelectric element 27 is in a de-energized state, flammable gas with the risk of explosion that enters from the inlet 11 is closed by the valve body 22 pushed against the valve seat 20 by the spring 21 and does not flow to the outlet 12 side. There is no state. When a voltage is applied to the electric terminal 36, the tip of the unimorph piezoelectric element 27 overcomes the biasing force of the distortion spring 21, and the valve body 2
Open 2. As a result, combustible gas flows from the inlet 11 to the outlet 12. In order to control the flow rate, by changing the voltage applied to the unimorph piezoelectric element 27, the displacement amount of the tip of the unimorph piezoelectric element 27 is changed, so that the flow rate can be controlled. At this time, the combustible gas flows into the flow path chamber 18,
The drive chamber 19 is filled.

Now, when the flow path chamber 18 and the drive chamber 19 are filled with flammable gas, air enters the fluid control valve 37 for some reason, and the concentration of the flammable gas is within the explosive range.
Further, it is assumed that, for example, a large impact is applied from the outside of the fluid control valve 37 and a crack or the like occurs in the ceramic 26.

When a voltage is applied to the unimorph piezoelectric element 27 under these conditions, a discharge occurs in the crank portion of the ceramic 26. At this time, the combustible gas in the drive chamber 19 whose concentration is within the explosive range explodes. However, the explosion occurred in drive room 19.
In other words, even if an explosion occurs in the drive chamber 19, the explosion-proof heat absorbing member 17 absorbs the explosion heat generated during the explosion, so the explosion-proof heat absorbing member 17 absorbs the explosion heat from the shaft hole 24. The temperature of the blast into the flow chamber 18 is reduced so that the flow chamber 18 does not explode.

Note that the use of a wire mesh as the explosion-proof heat absorbing member 17 has also been effective. However, the use of a metal plate has good thermal conductivity, so it is possible to efficiently absorb thermal energy during an explosion. The same applies even if the piezoelectric body is a bimorph element.

Next, another embodiment of the explosion-proof heat absorbing member will be described. In the embodiment shown in Fig. 4, ceramic 38 is used as an explosion-proof heat absorbing member.
It is composed of a non-conductive heat absorbing body such as. In this embodiment, when the unimorph piezoelectric element is distorted to open the valve body, insulation is ensured between the ceramic surface that constitutes the electrode surface of the unimorph piezoelectric element and the ceramic 38 that is the explosion-proof heat absorbing member. It is something.

In the embodiment shown in FIGS. 5 and 6 of the present invention, the explosion-proof heat absorbing member 39 has a corrugated plate-like structure with projections and depressions. In this embodiment, the surface area of the endothermic surface can be increased and the endothermic effect can be increased. In addition,
The same parts as in the above embodiment are given the same reference numerals and detailed explanations are omitted.

Effects of the Invention As described above, the fluid control valve of the present invention includes a valve frame body having a fluid inlet and an outlet, a flow path chamber having a valve body for opening and closing a flow path between the inlet and the outlet, and the valve body. By partitioning a drive chamber including a piezoelectric body that drives the body, the flow path chamber, and the drive chamber with an explosion-proof heat absorbing member, the piezoelectric body If a breakdown occurs and an explosion occurs in the drive chamber, the explosion-proof heat absorbing member absorbs the thermal energy at the time of the explosion, so the explosion will not propagate to the flow path chamber. In addition, since the explosion occurs within the drive chamber, the pressure rise during the explosion is small, and even if it is not designed as a pressure vessel, the valve body will not be damaged, making it possible to reduce costs while maintaining explosion-proof function. Furthermore, since the explosion-proof heat-absorbing member is always in contact with the fluid, the explosion-proof heat-absorbing member is always maintained close to the fluid temperature, and has a stable heat-absorbing effect unaffected by fluctuations in outside air temperature.

Further, in the present invention, by using a metal plate as an explosion-proof heat-absorbing member, it has good thermal conductivity and can efficiently absorb thermal energy during an explosion. Furthermore, by using a metal plate, the cost of the explosion-proof heat absorbing member can be reduced.

Further, in the present invention, by using a non-conductive heat absorbing body, insulation is ensured between the ceramic surface of the piezoelectric body that constitutes the electrode surface of the piezoelectric body and the non-conductive heat absorbing body, so heat is absorbed from the piezoelectric body. There is no leak discharge to the body, and reliability is improved.

Further, according to the present invention, at least the surface of the explosion-proof heat absorbing member on the driving chamber side is provided with unevenness means for increasing the surface area, so that the heat absorbing area is expanded, so that the heat absorbing effect can be enhanced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a fluid control valve showing an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line AA' in Fig. 1, and Figs. 3 and 4 are perspective views showing an explosion-proof heat absorbing member. Figure 5 is a vertical sectional view of a fluid control valve using another explosion-proof heat absorbing member, Figure 6 is a BB' sectional view of Figure 5, and Figure 7 is a sectional view of a conventional fluid control valve. It is. 10... Valve body, 11... Entrance, 12
...Outlet, 17...Explosion-proof heat absorbing member,
1B...Flow path chamber, 19...Drive chamber, 2
2... Valve body, 27... Piezoelectric body. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 3 If! 1 Figure 1θ ・--Chit τ(iA(n・-Population I2-Exit I7・-Market) Suction adjustment member 18- Flow rate screw 19--・-Drive! 22-1 body 2γ・-Piezoelectric 3 Book Figure 2 Figure 5 Figure 6

Claims (4)

[Claims] (1) A valve body having a fluid inlet and an outlet, and a flow path chamber having a valve body that opens and closes a flow path between the inlet and the outlet;
A fluid control valve comprising a drive chamber having a piezoelectric body that drives the valve body, and an explosion-proof heat absorption member that partitions the flow path chamber and the drive chamber. (2) The fluid control valve according to claim 1, wherein the explosion-proof heat absorbing member is a metal plate. (3) Claim (
1) The fluid control valve described above. (4) At least the surface of the explosion-proof heat absorbing member on the drive chamber side is
The fluid control valve according to claim 1, further comprising unevenness means for increasing the surface area.