JPS5926133Y2 - Electric valve safety device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a safety device for an electric valve.

Electric valve operating machines using motors of 40 to 50 W or less are often used for ball valves and butterfly valves.

However, with electric actuators, there are cases where the valve body and valve seat are stuck and do not move, or solid matter gets caught between the valve body and valve seat during the opening and closing operations of the valve, causing the valve body to become stuck in the middle. Most motors do not have a safety device to prevent motor burnout in the event that the motor stops midway due to overload, such as when the motor does not move, and those with a safety device are extremely expensive.

The wiring for conventional electric actuators is as shown in Figure 1 when the valve is fully closed, and A and B are single-phase 100 V and 200 V.
represents each pole of a power source, such as, and a voltage is applied between them.

S is a changeover switch operated by a person, So is the contact on the side where the valve opens, and Sn is the contact in the neutral position. Used when you want to stop the valve in the middle of opening or closing operation, or when you want to turn off the power. However, S5 is a contact point on the side that closes the valve.

MO9M5 is a switching microswitch, which is activated by moving the valve stem up and down or by rotating it.

M is a motor, and although detailed component wiring attached to motor M is not shown in the figure, there is a switching microswitch M.

Valve mid-position contact contact N that is in contact while the valve is in the mid-open/close position.

Connect to the normal rotation terminal of motor M.

On the other hand, the valve mid-position contact N of the other switching microswitch M5.

Connect the reverse terminal of motor M with the switching micro switch M.

When current flows through the valve mid-position contact Nc of , the motor M rotates in the valve opening direction, and the valve mid-position contact Nc of the other switching microswitch M5 is turned on.

When current flows through it, the motor M rotates in the direction of closing the valve.

The operation will be explained with reference to FIG. 2. When the valve is fully closed, the changeover switch S is connected to the contact S.

When switched to , the switching micro switch M is activated.

Current flows to the motor M through the valve mid-position contact NC, and the valve begins to open.

As soon as the valve starts to open, the switching microswitch MS has contact N.

From valve mid-position contact contact N.

(This is necessary if the valve is left partially open during the opening operation and then closed).

When the valve is fully open, the switching micro switch M is activated.

Valve mid-position contact contact N. Switches from to contact No., the current is cut off, and the motor M stops.

To close the valve, switch the changeover switch S to the contact turtle, and the valve mid-position contact N of the changeover microswitch M5.

Current flows through the motor M, causing the motor M to reverse rotation and the valve to begin closing.

When the valve starts to close, the micro switch M switches immediately.

is contact point N.

to the valve mid-position contact (this is necessary if the valve is left partially open during the valve closing operation and then opened).

When the valve is fully open, the switching microswitch M5 changes from the valve mid-position contact contact to the contact N.

The current is cut off and the motor M stops.

When the valve is stopped in a half-open state, selector micro switch M is used.

and M5 are both valve mid-position contact N.

, is on the No side, so if the changeover switch S is set to the contact So, the valve opens, and if the switch is set to the contact S5, the valve is closed.

In the above circuit, if an accident occurs in which the valve body becomes stuck during the opening or closing operation of the valve, the valve stem of the valve will not move and the rotation of the motor M will stop.

However, the switching micro switch M.

and M5, since the valve is fully open or not fully open, the valve mid-position contact contact Nc to contact N.

, the current to the motor M is not cut off, and the motor M is burnt out.

To prevent such burnout of the motor, mechanical shear pins or friction clutches are installed, but the motor continues to rotate even though the valve stem does not move.

Therefore, short-time rated motors generally used in electric valve actuators are undesirable because the temperature will rise unless the operator notices the accident early and turns off the current.

In addition, as an electrical method, the temperature of the motor is detected,
This method is used to cut off the current flowing to the motor.

In this case, since a temperature detection element must be provided in the motor, a special motor is required, which not only increases the cost but also causes the inconvenience that a general-purpose motor cannot be used.

Furthermore, it takes time for the temperature to rise, making it difficult to immediately detect abnormalities in valve opening/closing operations.

Another electrical method is to detect the current flowing through the motor and cut off the current flowing through the motor when it exceeds a certain value.

However, since a large current flows when the motor starts, it is necessary to exclude this current at the time of starting, which makes the circuit complicated and expensive.

The present invention eliminates the above-mentioned drawbacks and focuses on the fact that the time required to open or close a valve is constant, and if the valve does not fully open or fully open after this fixed time, the motor is activated by the action of a timer. The purpose of this invention is to provide a safety device for a motor-operated valve that can cut off the current flowing to the motor-operated valve and issue an alarm if necessary.

Therefore, since the safety device of the present invention is operated by a person to open and close the valve, the electric valve, which is based on a changeover switch and a microswitch that operates when the valve is fully open or fully open, turns off the power to the motor, can be used to switch off the power supply. One contact S of the changeover switch S connected to one pole A.

Valve mid-position contact Nc of the switching microswitch MO connected to the valve mid-position contact Nc of the switching microswitch MO connected to the valve mid-position contact contact N of the switching microswitch M5 connected to the other contact Ss of the changeover switch S
.

The two timers T are designed to open only when the valves are fully open and fully closed, respectively.

and D, respectively, are the two switching microswitches M
.

and M5 valve mid-position contact contact N.

, Nc and the other pole B of the power supply, these timers T.

and a switch T opened by Ts.

Micro switch MO to switch No and T5No respectively
After the set time of this timer, by interposing them in series between the valve mid-position contact contacts No. and No. of the MS and the forward rotation terminal and reverse rotation terminal of the motor M, or between the motor and the other pole of the power supply. The feature is that the power to the motor is turned off.

Further, the present invention has the following embodiments.

Changeover micro switch M.

Valve open end contact contact No. and valve closed end contact contact No. of the other switching microswitch MS.

and a lamp L between the other pole B of the power supply and the other pole B, respectively.

and intervening L5. Timer T.

In parallel to this, a contact T is closed by this timer To.

No and lamp L. In addition to providing a circuit in which E is connected in series, a circuit is provided in parallel with another timer T5 in which a contact TsNo and a lamp LsE, which are closed by this timer T5, are connected in a value series.

Two changeover microswitches M.

and M5 are the switch pieces M, respectively.

1 and M. 2 and Ms 1 and M82 have a common terminal,
It is a double-throw type that operates simultaneously, and one terminal of the timer T is connected to the two switching microswitches M.

and one each of M5 mid-valve contact contacts N.

, No., and the other terminal is connected to the other terminal B of the power supply, and the two microswitches M are connected together.

and each other valve mid-position contact contact N of M5.

, No are connected to the forward rotation terminal and the reverse rotation terminal of the motor M, and a switch Tnc that is opened by the timer T is interposed between the other terminal of the motor M and the other pole B of the power source.

Switch micro switch M.

Valve open end contact contact N.

and the valve closing end contact N of the other switching microswitch MS.

Lamp L between and the other pole B of the power supply. and, intervening.

This is because a contact TNO, which is closed by a timer T, and a lamp LE are interposed in series between one pole A and the other pole B of the power supply.

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

In FIG. 3, To and Ts are timers set to a time slightly longer than the time required to open and close the valve (to time and color time in FIG. 2), respectively, and are connected to two switching microswitches M.

and Ms valve mid-position contact contact N.

, No and the pole B of the power supply.

ToNC5T5No is each timer T. , Ts are contacts that are closed until the set time and open after the set time.

And a switching micro switch M. and M5 valve mid-position contact contact N.

, No. and the forward rotation terminal and reverse rotation terminal of the motor M.

Other details are the same as in Figure 1. In this circuit, the basic valve opening and closing operations are the same as those in Figure 1, but even if the valve body does not move during the opening or closing operation and the motor M is restricted, the timer T .

Or after the time set to T5, contact T.

By opening No or T5Nc, the current flowing to the motor M can be reliably cut off.

The embodiment shown in FIG. 4 is the switching microswitch M in the embodiment shown in FIG.

Valve open end contact contact No. and valve closed end contact contact No. of the other switching microswitch MS.

and a fully open lamp L between and pole B of the power supply, respectively.

and a fully closed lamp Ls is interposed. Furthermore, timer To
In parallel to this, a contact T is closed by this timer To.

A circuit is provided that connects No in series with the abnormal lamp LoE during the opening operation.

Further, a circuit is provided in parallel with another timer Ts, in which a contact T5No that is closed by this timer Ts and a lamp Lse are connected in series.

In this circuit, each state of the valve is fully open, fully closed, abnormality in the middle of opening operation, and abnormality in the middle of closing operation, respectively, with lights Lo, Ls, and L.
It is indicated by OE or LsE and is more convenient to use than the one shown in FIG.

Figure 5 shows how the timer is set to 1 when the valve opening and closing operation times (to time and ts waiting time in Figure 2 are the same or almost the same).
This is an example using only one.

That is, two switching microswitches M.

and MS are the switch pieces M, respectively.

1 and M. 2, M51, and M52 have a common terminal and are of double-pole, double-throw type that operate simultaneously, and the changeover switch S is similarly a double-pole, double-throw type of switch S1 and S2.

Also, one terminal of the timer T is connected to one valve mid-position contact contact N of each of the two switching microswitches MO and M5.

. No. and connect the other terminals to power supply electrode B.
Connect to.

Two microswitches M. and each other valve mid-position contact contact N of M5.

. No. is connected to the normal rotation terminal and the reverse rotation terminal of the motor M, and a switch TNc that is opened by the timer T is interposed between the other terminal of the motor M and the power supply electrode B.

Changeover micro switch M. Valve open end contact contact N.

and the valve closing end contact N of the other switching microswitch M5.

and the power supply electrode B, as in Fig. 4.
A fully open lamp Lo and a fully closed lamp L5 are interposed.

Between the power supply electrodes A and B, a contact TNo that is closed by a timer T and an abnormality lamp LE that is in the middle of a valve opening/closing operation are interposed in series.

The switch TNc remains closed until the time set by the timer T (a time slightly longer than the period of rain required to open and close the valve).

All of the above examples are for small electrical capacity, but if the electrical capacity is insufficient when the current is cut off directly to the motor using a changeover switch or changeover microswitch,
You can use a relay together.

Further, when using a small three-phase motor, a relay for forward and reverse rotation of the three-phase motor may be inserted in the part corresponding to the motor in the above example to make it suitable for the three-phase motor.

Furthermore, in addition to the lamp indications shown in Figures 4 and 5, if the valve does not fully operate and danger is predicted, a signal from the timer (a signal flowing through the abnormality lamp circuit) will sound a siren. It can be used for applications such as making a sound or automatically operating valves other than this one.

As described above, according to the present invention, if a standard motor is used and the valve does not operate normally even after the time required to open and close the valve, and an abnormality occurs, after a certain amount of time has passed, In addition to automatically stopping the motor, by installing a standard device called a timer, it is possible to easily provide a safety device.

[Brief explanation of drawings]

Fig. 1 is a wiring diagram of a conventional valve electric operating machine, Fig. 2 is an operation diagram of the valve electric operating machine shown in Fig. 1, Fig. 3 is a wiring diagram of an embodiment of the present invention, and Fig. 4 is a wiring diagram of a conventional valve electric operating machine. Wiring diagram of another embodiment of the present invention, FIG. 5 is a wiring diagram of yet another embodiment of the present invention. S: Changeover switch, So: Valve open contact, So: Valve close contact, MO9Ms: Switching micro switch, No: Valve open position contact contact, NC: Valve open/close mid-position contact contact, To,
T5. 'r: timer.

Claims (1)

[Scope of claim for utility model registration] 1 One contact S of a changeover switch S connected to one pole A of the power supply
. Switching micro switch M connected to. Valve mid-position contact Nc of the switching microswitch M5 connected to the valve mid-position contact Nc of the switching microswitch M5 and the other contact Ss of the changeover switch S.
. and the two timers To and D, respectively, by the two switching microswitches M. and MS valve mid-position contact contact N. , No. and the other pole B of the power supply, these timers T. and switches ToNc and To5N opened by Ts.
ce each switching micro switch M. and safety of a motor-operated valve characterized in that it is interposed in series between the valve mid-position contact contacts Nc, Nc of M5 and the forward rotation terminal and reverse rotation terminal of the motor M, or between the motor and the other pole of the power supply. Device. 2 Changeover micro switch M. Valve open end contact contact N. and the valve closing end contact N of the other switching microswitch M5. and a lamp L between the other pole B of the power supply and the other pole B, respectively. and a safety device for an electric valve according to claim 1, in which L5 is interposed. 3 Timer T. A utility model registration request in which a circuit is provided in which a contact ToN is directly coupled to a lamp LoE in parallel to the timer T5, and a circuit is provided in which a contact TsNo and a lamp LsE are coupled in series to another timer T5 in parallel. A safety device for an electric valve according to scope 2. 4 Two changeover microswitches M. and M5 are the switch pieces M, respectively. 1 and M. 2 and Ms 1 and Ms 2 have a common terminal and are of double-throw type that operate simultaneously, and one terminal of the timer T is connected to the two switching microswitches M. and MS, respectively, one valve mid-position contact contact Nc, N
c and the other terminal is connected to the other pole B of the power source, and the other valve mid-position contact N of the two microswitches MO and MS, respectively. , No are connected to the forward rotation terminal and reverse rotation terminal of the motor M, and a switch T is connected between the other terminal of the motor M and the other electrode B.
A safety device for an electric valve as set forth in claim 2 of the utility model registration claim in which an NC is interposed. 5 Changeover micro switch M. Valve open end contact contact N. and the valve closing end contact N of the other switching microswitch M5. Lamp L between and the other pole B of the power supply. and a safety device for an electric valve according to claim 4 of the utility model registration claim in which L5 is interposed. 6. The safety device for an electric valve according to claim 5, which is a utility model registration, in which a contact TNo and a lamp LE are interposed in series between one pole A and the other pole B of a power source.