JPH032072Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a drive circuit for a gas on-off valve that electromagnetically opens and closes a gas flow path.

[Prior art and its problems]

Gas leak alarm safety devices are being promoted as the mainstay of gas protection equipment, but these safety devices are gradually changing from simply blocking the gas flow path electromagnetically to opening the gas flow path electromagnetically. It is now turning into an on-off valve that controls blockage. FIG. 2 shows a conventional example of a driving circuit for such a gas passage opening/closing valve. In FIG. 2, two capacitors 1 and 2 are connected via diodes 3 and 4, respectively, so that they are constantly charged. A series circuit of a thyristor 5 and a transistor 7 is connected in parallel to the capacitor 1, and a series circuit of a thyristor 6 and a transistor 8 is connected in parallel to the capacitor 2. A coil 9 is connected between both cathodes of both thyristors 5 and 6. Here, in the series circuit of thyristor 5 and transistor 7 or the series circuit of thyristor 6 and transistor 8, the thyristor and the transistor do not conduct at the same time, as described below, so both operate as discharge circuits for the respective capacitors 1 and 2. do not. The discharge circuit of capacitor 1 is a series circuit of thyristor 5-coil 9-transistor 8, and the discharge circuit of capacitor 2 is a series circuit of thyristor 6-coil 9-transistor 7. To do this, the gate of thyristor 5 and the base of transistor 8 are each connected to a safety resistor 1.
1 and 12, both are connected to the opening operation input terminal 15. Further, the gate of the thyristor 6 and the base of the transistor 7 are both connected to a closing operation input terminal 16 via safety resistors 13 and 14, respectively.

Since both capacitors 1 and 2 are constantly charged, when an open signal is applied to the open operation input terminal 15, thyristor 5 and transistor 8 become conductive, and a pulse is generated from capacitor 1 in the direction of thyristor 5 - coil 9 - transistor 8. A current _I1 flows, and an on-off valve (not shown) is opened by the electromagnetic force of the coil 9. Further, when a closing signal is applied to the closing operation input terminal 16, the thyristor 6 and the transistor 7 become conductive, and a pulse current I ₂ flows from the capacitor 2 in the direction of the thyristor 6 - coil 9 - transistor 7;
Since the direction is opposite to _I1 , the on-off valve is closed. Further, an open signal is input to the open operation input terminal 15, and an open signal is input to the close operation input terminal 1.
When close signals are applied to capacitors 6 and 6 at the same time, both thyristors 5 and 6 and both transistors 7 and 8 become conductive at the same time, so the charge in capacitor 1 is discharged through thyristor 5 and transistor 7, and capacitor 2
Since the charges are discharged through the thyristor 6 and the transistor 8, almost no pulse current flows through the coil 9. Therefore, the on-off valve maintains the state it was in before both signals were applied. In other words, both transistors 7 and 8 have the effect of interlocking the operation of the on-off valve by being conductive.

By the way, in the operation of the on-off valve by discharging a capacitor, the capacitor is normally charged at 15 to 25V, and in order to discharge the charge of this capacitor to a coil load of about 5Ω, both the switching element and the transistor need 3V. A current withstand capacity of about ~5 A is required, and even if the switching element is unavoidable, it has a relatively large current withstand capacity as a transistor, and the disadvantage is that the energy consumption within the transistor is large and the efficiency of valve drive is reduced. Furthermore, when the open signal and the close signal are applied simultaneously, the on-off valve does not operate normally, but each discharge current flows through the opposing transistor, resulting in unnecessary energy loss.

[Purpose of invention]

The object of the present invention is to provide a drive circuit for a gas on-off valve that reduces valve drive energy and interlock energy.

[Key points of the idea]

The key point of this invention is to discharge the electric charge of two charged capacitors in opposite directions to a common coil through two sets of switching elements that conduct with open and close operation signals, and generate electricity in this coil. In a drive circuit for a gas on-off valve that opens and closes the valve using electromagnetic force, a transistor is inserted between the operation terminals of each of the switching elements,
The transistors are connected to each other in such a way that they become conductive in response to the operation signal of the thyristor on the opposite side, and when the operation signal is applied to one switching element, the thyristor is connected between the operation terminals of the switching element on the opposite side of this switching element. The idea is to prevent the large discharge current of the capacitor from flowing through the transistor by making the transistor conductive and short-circuiting the switching element, thereby locking the conduction of the switching element.

[Example of idea]

An embodiment of the present invention will be described in detail based on FIG. In Figure 1, two capacitors 1,
2 are connected to be constantly charged via diodes 3 and 4, respectively. A series circuit of a thyristor 5 and a coil 9 is connected in parallel to the capacitor 1, and a series circuit of a thyristor 6 and a coil 9 is connected in parallel to the capacitor 2, forming discharge circuits for the capacitors 1 and 2, respectively. In other words, the coil 9 is inserted commonly into the discharge circuit of the capacitor 1 and the discharge circuit of the capacitor 2, and is connected so as to discharge the charges of both capacitors 1 and 2 in opposite directions. A transistor 7 is connected between the gate and cathode of the thyristor 5, and the thyristor 6
A transistor 8 is connected between the gate and cathode of. Also, the gate of thyristor 5 and the base of transistor 8 are connected to safety resistors 11 and 12, respectively.
The gate of the thyristor 6 and the base of the transistor 7 are connected together to the closing input 16 via safety resistors 13 and 14, respectively.

Since both capacitors 1 and 2 are constantly charged, when an open signal is applied to the open operation input terminal 15, the thyristor 5 becomes conductive, discharging the capacitor 1,
A pulse current _I1 flows through the thyristor 5-coil 9, and the electromagnetic force of this coil opens an on-off valve (not shown). At this time, the transistor 8 becomes conductive and the gate of the thyristor 6 is short-circuited.
The conduction of the thyristor 6 is prevented. Further, when a close signal is applied to the close signal input terminal 16, the thyristor 6 becomes conductive, discharging the capacitor 2, and generating a pulse current I ₂
flows into the thyristor 6-coil 9, and this direction is
Since the direction is opposite to the pulse current _I1 , the on-off valve is closed. At this time, transistor 7 becomes conductive at the same time.
Since the gate of thyristor 5 is short-circuited, conduction of thyristor 5 is prevented. That is, both transistors 7 and 8 interlock the respective thyristors 5 and 6 by being conductive. Further, when an open signal is simultaneously applied to the open operation input terminal 15 and a close signal is applied to the close operation input terminal 16, both transistors 7,
Since both thyristors 8 and 8 are conductive at the same time, the gates of both thyristors 5 and 6 are short-circuited, and since respective signals are not applied to the gates of both thyristors 5 and 6, both thyristors 5 and 6 are not conductive. Therefore, the on-off valve does not open or close, but maintains the state it was in before both signals were applied. At this time, both transistors 7 and 8
This means that the thyristors are interlocked with each other.

[Effect of idea]

According to the present invention, one switching element becomes conductive in response to an operation signal to flow a pulse current in one direction to the coil to open the on-off valve, or the other switching element becomes conductive to flow a pulse current in the opposite direction to the coil. In a drive circuit for a gas on-off valve that closes the on-off valve by flowing a current, when one switching element conducts, the other switching element conducts the transistor connected between the operation terminals of that switching element, thereby closing the operation terminals. By short-circuiting and locking, a large current such as the coil current that flows through the interlock transistor does not flow through the interlock transistor, so the interlock energy is small compared to the valve drive energy, resulting in high efficiency. Furthermore, when an operation signal is applied to both switching elements, the transistors on the opposite side short-circuit the operation terminals of each switching element, so in this case, the discharge current of the capacitor does not flow to the switching element either, wasting energy. It has the effect of not consuming

[Brief explanation of drawings]

FIG. 1 is a wiring diagram showing an embodiment of a drive circuit for a gas on-off valve according to the present invention, and FIG. 2 is a wiring diagram showing an example of a conventional drive circuit for a gas on-off valve. 1, 2... Capacitor, 5, 6... Thyristor, 7, 8... Transistor.

Claims (1)

[Scope of utility model registration request] The electric charges of the two charged capacitors are discharged in opposite directions to a common coil through two sets of switching elements that conduct with open and close operation signals, and each electromagnetic force generated in this coil In a drive circuit for a gas on-off valve that opens and closes the valve, a transistor is inserted between the operation terminals of each of the switching elements, and the transistors are connected so as to be electrically connected by the operation signal of the thyristor on the opposite side. Features a gas on-off valve drive circuit.