JPH0664978B2 - Pressure-electric switch device - Google Patents

Description

TECHNICAL FIELD The present invention uses a pressure-electric switch whose electric switching state is switched according to the pressure of gas such as air, and converts a change in gas pressure into an electric signal. Pressure-electric switch device.

[Conventional technology]

In recent years, a system combining an air circuit and an electric circuit has been developed. As this system, for example, there is a system that monitors a change in the air pressure of an air circuit and executes a predetermined process by an electric circuit according to the monitoring result. In this case, the monitoring of the air pressure in the air circuit is done by an electric circuit, which requires means for converting the change in air pressure into an electric signal. As this pressure-electricity conversion means, for example, there is a pressure-electrical switch that can switch on / off of a micro switch according to air pressure. When the air-pressure is converted into an electric signal by the pressure-electric switch, two judgment results of the air pressure are obtained whether or not this is larger than a predetermined pressure.

Considering a system that uses a pressure-electric switch as pressure-electric conversion means and executes a predetermined process by an electric circuit according to the air pressure in the air circuit, this system is further divided into the following two systems. It is possible. That is, one is a system in which the on / off state of the pressure-electric switch is always made to follow changes in air pressure. That is, when the air pressure is equal to or higher than the predetermined pressure, the pressure-electric switch is always kept in the on (or off) state, and when the air pressure is less than the predetermined pressure, it is always kept in the off (or on) state. On the other hand, the other one, for example, switches the pressure-electric switch from the off (or on) state to the on (or off) state at one time each time the air pressure reaches a predetermined pressure, and then immediately after that. It returns to the off (or on) state. In other words, the pressure-electric switch is used as a trigger switch.

In the latter case, a structure is required to return the pressure-electric switch to its initial state. In other words, the transmission path for transmitting air from the air circuit to the pressure-electric switch is generally closed, so if the air pressure in this transmission path reaches a predetermined pressure, the air pressure in the air circuit will drop. Only then can the pressure-electric switch be set to its initial state.

Therefore, conventionally, as shown in FIG. 2, a solenoid valve 14 is inserted in an air transmission path 13 between an air source 11 and a pressure-electric switch 12, such as an air circuit. Then, a predetermined time after the air pressure reaches a predetermined pressure and the switch 12 is switched from the off (or on) state to the on (or off) state, the solenoid valve 14 is set to the open state and the air in the transmission path 13 is set. Is released into the atmosphere. In this case, the electric signal for controlling the opening / closing of the solenoid valve 14 is obtained from the electric circuit 15.

Here, the operation of FIG. 2 will be briefly described. Now the air source 11
The actual air pressure inside is P ₁ , the pressure-electric switch 12 is on,
Let P _G be the air pressure that becomes the boundary for switching the OFF state. In the illustrated system, when P ₁ -P _G <0 ...... (1), the movable contact piece 121 of the switch 12 is connected to the terminal 122 and 123. This state corresponds to the off state of the switch 12.
On the other hand, when P ₁ −P _G ≧ 0 (2), the movable contact piece 121 of the switch 12 is shifted by the air pressure P ₁ and connected to the terminals 124 and 125. This allows
The switch 12 is turned on. As a result, terminal 15 of electrical circuit 15
Similarly, a DC signal or an AC signal flows from the terminal 1 to the terminal 152 of the electric circuit 15 through the switch 12, and the electric circuit 15 is pneumatically operated.
You can see that P ₁ is greater than P _G.

[Problems to be solved by the invention]

However, in the configuration where the pressure-electric switch 12 is initialized by the solenoid valve 14, the system is not a gas as air but
If the system handles explosive gases, or if the system is used in an explosive environment,
Solenoid valve that cannot be used at all or for explosion protection
There are considerable restrictions on the layout of 14 and electrical wiring.

The present invention has been made to address the above-mentioned circumstances, and its purpose is to provide almost no explosion protection even when the system handles explosive gas or is used in an explosive environment. It is to provide a pressure-electrical switching device that can be used without thinking.

[Means and Actions for Solving Problems]

The present invention forms an air circuit using air to drive a pressure-electric switch, and the air circuit enables the pressure-
The electric switch is designed to be initialized.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of one embodiment.

In FIG. 1, reference numeral 21 is an air source such as an air circuit. The air output from this air source 21 is the pressure-electric switch 22.
Is supplied to. This pressure-electric switch 22 is
When the air pressure P ₁ given by is less than the specified pressure P _G
When P ₁ <P _G , the movable contact piece 221 is connected to the fixed terminals 222 and 22. In FIG. 1, this corresponds to the off state. On the other hand, when the air pressure P ₁ becomes equal to or higher than the predetermined pressure P _G , P ₁ ≧ P _G , the air pressure P ₁ moves the movable contact piece 221, and the movable contact piece 221 moves the terminal 224,
Connected to 225. As a result, the switch 22 is turned on, and for example, the switch 22 is connected to the terminal 231 of the electric circuit 23.
A DC signal or an AC signal flows through the movable contact piece 221 to the terminal 232.

Here, the switch that has switched from the off state to the on state
A configuration for returning the switch 22 to the off state and initializing the driving of the switch 22 will be described. This initialization is performed by the air source 21
Is performed by an air circuit using the air provided to the switch 22 from.

First, the air supplied from the air source 21 to the switch 22, guide Beauty from the input port a ₁ of the switch 22 in the interior of the switch 22, although the movable contact piece 221 is not applying pressure, P ₁
When ≧ P _G and the movable contact piece 221 is connected to the terminals 224 and 225 (the switch 22 is in the ON state), the port a _{2 of the} switch 22 communicates with the inside of the switch. This allows ports a ₂ to P _G
Alternatively, air having a pressure proportional to this is supplied to the control port b ₁ of the delay device 24. Hereinafter, the pressure in P _G or with this is output from the port a ₂ proportional mark the S _1.

The input port b ₂ of the delay device 24 is
The air guided to a ₁ is guided. Then, when the air pressure of the control port b ₁ becomes S ₁ , the delay device 24 outputs the air guided to the input port b ₂ from the output port b ₃ after a predetermined delay time from this time. . As when the air pressure in the control port b ₁ is S _1, since the air pressure in the input port a ₁ switch 22 not healed even take is when P _G, air pressure input port b ₂ of the delay unit 24 is also a P _G Has become. Therefore, at this time, P _G or the air pressure proportional thereto is obtained at the output port b ₃ of the delay device 24. Hereinafter, this is referred to as S ₂ .

The air output from the output port b ₃ of the delay unit 24 is a 3-port valve.
Guided to 25 pilot ports c ₁ . This 3 port valve
25 is a normally open spring return type valve, and when there is no control input to the pilot port c ₁ (first
In the example of the figure, the output port of the delay unit 24 will be described later in detail.
When the air pressure of b ₃ is low), the ports c ₂ and c ₃ are in a conductive state. Here, since the port c ₂ is connected to the air source 21 and the port c ₃ is connected to the input port a ₁ of the switch 22, when the air pressure of the output port b ₃ of the delay device 24 is low,
Air transmission path between air source 21 and input port a _{1 of} switch 22
Xa is conducting.

In contrast, the air pressure P _{1 at} the input port a ₁ of the switch 22 is P ₁
≥ P _G , the delay device 24 turns on and S _{2 is} output to its output port b _3.
When the air pressure is obtained, the ports c ₃ and c _{4 of} the 3-port valve 25 are brought into conduction. As a result, the air transmission path Xa connecting the air source 21 and the input port a ₁ of the switch 22 and the air source
The air in the air transmission path Xb connecting 21 and the input port b ₂ of the delay device 24 is released into the atmosphere from the port c ₄ of the 3-port valve 25,
The air pressure P ₁ in the transmission paths Xa and Xb decreases. This reduction in the air pressure P _1, becomes a P ₁ <P _G, the movable contact piece of the switch 22 22
1 shifts to the fixed terminals 222 and 223 side, and the switch 22 is returned to the off state.

After that, when the air pressure P ₁ in the transmission path Xa further decreases, the valve 27 in which the air in the transmission path Xa is input to the control ports d ₁ and e ₁ opens the gate. The input port d ₂ of valve 26 is
This valve 26 releases the air in the transmission path Xc from the output port d ₃ to the atmosphere by opening the gate as the air pressure P _{1 in the} transmission path Xa decreases. As a result, the delay device 24 is set to the off state. Similarly, the input port e ₂ of the valve 27 is connected to the transmission path Xd, and this valve 27 is connected to the transmission path Xa.
When the air pressure P ₁ decreases, the air in the transmission path Xd is output
Output from e ₃ . As a result, the 3-port valve 25 returns to the state in which the ports c ₂ and c ₃ are electrically connected by the spring return.

This completes the initialization for re-driving the switch 22. Therefore, after this, the air pressure P ₁ of the transmission path Xa is again increased.
If P _G or higher, the same operation is performed.

As described above in detail, in this embodiment, an air circuit is formed by using air for driving the switch 22 without using electricity, and the switch 22 is initialized by this air circuit. There is almost no need to think about the design for, and the design of the device becomes very easy.

Further, according to this embodiment, the output ports d ₃ and e _{3 of the} valves 26 and 27 are
By always forcibly closing, there is an advantage that a conventional device for initializing using electricity can be easily realized. That is, by forcibly closing the output ports d ₃ and e ₃ of the valves 26 and 27, the air in the transmission paths Xc and Xd is not released, so once the air pressure in the transmission path Xd becomes S ₂ , the 3 ports Even if the ports c ₃ and c _{4 of the} valve 25 are electrically connected to each other and the air pressure P ₁ of the transmission path Xa is reduced, the 3-port valve 25 is always in the state of electrically connecting the ports c ₃ and c ₄ .

Therefore, the transmission line Xa and the pilot port c ₁ of the 3-port valve 25
An electromagnetic solenoid sensitive to air pressure is installed between the transmission path Xa
When the air pressure P _{1 in the}
If 25 is forcibly driven and the ports c ₂ and c ₃ are electrically connected, a device for initializing the switch 22 using electricity can be realized as in the conventional case.

The present invention is not limited to the above embodiment.

For example, in FIG. 1, by removing the valve 26 and connecting the transmission path Xc to the input port e ₂ of the valve 27 as shown by the broken line A ₁ , the air in the transmission path X _{C can be changed} similarly to the transmission path Xd. May also be released by the valve 27. This is the same even if the valve 27 is omitted and the valve 26 is used.

Further, the input to the control port b ₁ of the delay device 24 may be taken not from the inside of the switch 22 but from the input port a ₁ side of the switch 22 as indicated by a broken line A ₂ . in this case,
If the threshold value is set to the control port b ₁ of the delay device 24 so that the delay device 24 turns on when the air pressure P ₁ of the transmission path Xa becomes P _G , the same operation as in the previous embodiment is obtained. be able to.

In addition, the transmission paths Xc, Xd for the decrease in the air pressure P ₁ of the transmission path Xa
If it is possible to speed up the followability of the decrease of the air pressure of the valve, the valves 26 and 27 are omitted, and the air of the transmission paths Xc and Xd is also a 3-port valve.
You may make it discharge using 25.

〔The invention's effect〕

As described above, according to the present invention, there is almost no need to consider a design for explosion proof even when handling a gas with an explosion risk or when using the system in an environment with an explosion risk. It is possible to provide an easy pressure-electric switch device.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a diagram for explaining the configuration of a conventional pressure-electric switch device. 21 …… Air source, 22 …… Pressure-electric switch, 24 …… Delay device, 25 …… 3-port valve, 26, 27 …… Valve, Xa, Xb, Xc, Xd ……
Transmission path.

Claims (1)

[Claims] 1. A first transmission path for guiding a gas from a gas source through a three-port valve, and an output portion of the first transmission path is connected to an input port. When the atmospheric pressure reaches a predetermined pressure, the atmospheric pressure switches the first switching state to the second switching state, and in the second switching state, the switching detection output by the atmospheric pressure is connected to the output port of the second transmission path. And an atmospheric pressure-electric switch for outputting to a control port of the three-port valve, delaying the change in the atmospheric pressure of the second transmission path, controlling the same, and releasing the gas of the first transmission path. Pressure-electric switch device, wherein the pressure-electric switch is initialized by lowering the internal pressure of the pressure-electric switch.