JPS593365B2 - How to release overload from cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overload release method for detecting an overload on a cooling device for transferring amorphous solid materials and automatically returning the cooling device to a normal operating state.

The cooling device for transferring amorphous solids is shown in Figures 1 and 2.
As shown in the figure, a transfer screw 4 is installed in a storage tank 1 which has a solid material supply port 2 at one end and a cooled solid material discharge port 3 at the other end, and its bottom surface is connected to the supply port 2 and the discharge port 3 at the other end. A refrigerant pool 5 is formed which slopes upward toward the outlet 3 and into which liquid nitrogen or the like is injected.

When this cooling device is in normal operation (in a state in which solids are cooled and transferred from the supply port 2 to the discharge port 3 in the refrigerant pool 5 by the rotation of the screw shaft 6 in the forward rotation direction), the solid material is supplied from the supply port 2. A solid substance a of various sizes and shapes is inserted between the supply port 2 and the rear end of the screw 4,
If the solid material a gets stuck in the gap between the outer peripheral edge of the storage tank 1 and the inner surface of the storage tank 1, resulting in an overload condition, the motor 7 is stopped by a protection circuit (thermal relay) built in the motor T, and the solid material a is no longer transferred.

In such a case, in order to release the jamming, the electric motor 7
must be reversed, but since the thermal relay is activated to stop the motor 7 when the current exceeds the rated current of the motor 7 for a certain period of time, the temperature of the motor 7 has risen, and the current must be reversed. For this purpose, it is necessary to manually turn on a push button switch or the like until the temperature drops.

・9 In this way, the transfer of solid material a was interrupted, and it took time and effort to restart the operation after the interruption.

As a solution to this problem, the present invention attempts to provide an overload release method that can automatically detect and release the overload state even if the cooling device is overloaded and return the cooling device to normal operating state. .

The present invention will be described in detail below with reference to the illustrated embodiments.
In FIG. 3, the cooling device A rotates a screw shaft 6 via an electric motor 7 and a drive device 8. When the teeth of a gear 9 attached to the screw shaft 6 pass through the sensitive surface of a proximity switch 10, a control unit 11 is activated. The built-in output contact 34 performs one inversion operation.

This output contact 34 repeats opening and closing the same number of times as the number of teeth passed, and inputs an electric pulse corresponding to the number of teeth to the preset counter 13 only when the rotation is reversed.

On the other hand, the overload detector 12, which operates based on the primary current of the motor 7, does not operate with the starting current when the motor is started, and is built into the detector 12 if an overcurrent flows for more than a certain period of time due to solid objects being caught during operation. The output contact 35 is operated in reverse, and is automatically restored when the current drops below a certain value.

When the start push button switch 14 is pressed during operation, the electromagnetic switch 15 is turned on and its main circuit contact 36 is closed, so that the motor 7 rotates in the normal direction and the solids in the cooling device A are transferred normally.

Since the electromagnetic switch 15 is self-held by its own contacts 19, it may continue to operate even if the push button switch 14 is released.

When the cooling device A becomes overloaded, the overload detector 12 is activated and the B contact of the output contact 35 is opened, so the electromagnetic switch 15 is demagnetized, the main circuit contact 36 is opened, and the motor 7 is stopped at the same time. The a contact of the output contact 35 is closed, the reverse rotation starting timer 24 is energized, and the instantaneous operation contact 25 is self-held.

When the electric motor 7 stops, the input current to the overload detector 12 becomes zero, so the output contact 35 returns to its original state.

After the timer 24 has timed out, its time contact 26 is closed, the reverse electromagnetic switch 16 is turned on, and when its main circuit contact 37 is closed, the motor 7 starts reverse rotation.

The electromagnetic switch 16 is self-held by its own contacts 21.

Further, the reverse rotation start timer 24 is demagnetized because the contact 22 is opened, and the contacts 25 and 26 are restored to their original state.

On the other hand, since the contact 23 is closed, the preset counter 13
receives the electrical pulse from the proximity switch 10 and starts counting.

Contacts 22 and 23 are auxiliary contacts of the electromagnetic switch 16.

When the electric motor 7 reverses to a predetermined rotation speed (the set value of the preset counter 13), the output contact 17 of the preset counter 13 is closed and the auxiliary relay 27 is energized.

This auxiliary relay 27 is self-held by its own contact 28, and at the same time, the normal rotation restart timer 32 is also excited.

At this time, since the contact 29 of the auxiliary relay 27 is opened, the demagnetized main circuit contact 37 of the reverse electromagnetic switch 16 is opened, and the motor 7 is stopped.

Further, since the contact 31 is closed and the contact 30 is opened, the preset counter 13 returns to zero, and its output contact 17
Also opens.

After the time limit of the normal rotation restart timer 32 has elapsed, the time limit contact 33 is closed, the electromagnetic switch 15 for normal rotation is closed again, and the motor 7 rotates in the normal direction.

In this case, the auxiliary relay 27 and the timer 32 are demagnetized by the opening of the contact 20, but the electromagnetic switch 15 is self-held by its own contact 19, so the motor 7 continues to rotate normally, and therefore the cooling device A operates normally. He will return.

The above operation is then automatically repeated.

In addition, when stopping the operation, when the stop push button switch 18 is pressed, the electromagnetic switch 15 is demagnetized, so the electric motor 7 is immediately stopped.

Further, although this embodiment is a diagram of the operating principle of a contact method using a high frequency oscillation type proximity switch 10 and an electromagnetic preset counter 13, it can also be replaced with other devices having equivalent functions or a non-contact method. However, commonly added safety devices (short circuit protectors, interlocks to prevent simultaneous activation of electromagnetic switches, etc.) are omitted.

Next, in the embodiment shown in FIG. 4, the reverse rotation position detection gear 9, the proximity switch 10, and the control unit 11 are removed from the embodiment shown in FIG. By changing the time limit setting, the screw shaft 6 of the motor 7 is automatically stopped at an arbitrary number of rotations in the reverse direction. The process leading to the automatic start of reverse rotation is the same as described above, and will therefore be omitted.

The electric motor 7 starts in reverse, that is, the reverse electromagnetic valve/closer 1
6, the auxiliary contact 23 is closed and the reverse rotation stop timer 38 is energized.

After the set time of the timer 38 has elapsed, the time contact 39 closes, energizing the auxiliary relay 27.

This auxiliary relay 27 is self-held by its own contacts 28, and at the same time, the forward rotation starting timer 32 is also excited.

At this time, the contact 29 of the auxiliary relay is opened, so the reverse electromagnetic switch 16 is demagnetized, the main circuit contact 37 is opened, and the motor 7 is stopped.

Further, since the auxiliary contact 23 is also opened and the timer 38 is demagnetized, the timer contact 39 is also opened.

Thereafter, the process leading to the automatic restart of normal rotation is the same as described in the embodiment shown in FIG.

By this reverse movement, the solid object a shown in FIG. 1 is released from the jammed state, and the overload state is released.

Next, after a certain period of time has elapsed according to a timer or the like after the automatic stop of the reverse rotation, the forward rotation is automatically started to return to the normal operating state and complete one cycle of operation for canceling the overload state.

Therefore, if the overload condition is not released after one cycle of operation, this cycle will be repeated.
According to experiments, it returns to normal after one cycle.
We were able to confirm that there was no need to repeat the process over and over again.

If the overload condition occurs repeatedly and exceeds a preset number of times within a certain period of time, it is natural to stop this cycle as an abnormal condition.

Various devices can be used to perform the above-mentioned overload detection, automatic stop, time limit, automatic reverse start, automatic stop, time limit, and automatic forward start, depending on the combination of electric circuit configurations, but they are limited to specific electric circuits. It's not something you can do.

As described above, the present invention has a supply port for the amorphous solid material at one end and a discharge port for the cooled solid material at the other end,
and a storage tank having a refrigerant pool at the bottom of which the bottom surface slopes upward from the supply port to the discharge port, and a solid material that is installed within the storage tank so as to be substantially parallel to the bottom surface and is supplied from the supply port. It includes a transfer screw that transfers the material through the refrigerant pool to the discharge port, and a reversible motor that rotates the transfer screw, and prevents the solid material being transferred from being caught between the inner surface of the storage tank and the transfer screw. When a load condition occurs, this overload is detected by the reversible motor, a control member is actuated by the detected signal, and the control member stops the reversible motor;
After a certain period of time has elapsed since the stop, the reversible motor is reversed by a predetermined number of revolutions to release the screw, and then after a certain period of time, the reversible motor is rotated forward to return to normal operation. Even if an overload condition occurs in the cooling device due to the jamming of amorphous solids, the overload condition can be automatically detected, the jamming can be released, and the normal operating state can be restored. In addition to almost eliminating the need to interrupt transfer or restart operation, for example, if the screw is immersed in a refrigerant pool for more than necessary, and the screw is also immersed in the refrigerant pool, jamming may become stronger. Wear of the screw that occurs when releasing the stuck solid material for a long time, etc.
It is possible to reliably prevent damage, etc., and it is completely unnecessary to use a reversible motor with a horsepower several times higher than the rated value in advance in anticipation of such a jammed state, and solid materials can be transferred smoothly and cooled. It has excellent effects such as being extremely effective in improving the reliability of equipment and improving work efficiency.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional front view of the cooling device, Figure 2 is Figure 1-I
The line sectional views, FIGS. 3 and 4, show an embodiment of the automatic reverse rotation stop circuit. 1... Storage tank, 2... Supply port, 3...
...Discharge port, 4...Screw, 5...
...Refrigerant pool, 6...Screw shaft, 7...
...Electric motor, 8...Drive device, 9...
... Gear, 10 ... Proximity switch, 11 ...
...Control unit, 12...Overload detector,
13...Preset counter, 14...
・Start push button switch, 15... Electromagnetic switch, 1
6... Reverse electromagnetic switch, 1B... Stop push button switch, 24... Reverse start timer, 2
7... Auxiliary relay, 32... Normal rotation restart timer, A... Cooling device, a... Solid object.

Claims (1)

[Claims] 1. A refrigerant pool having a supply port for amorphous solids at one end, a discharge port for the cooled solids at the other end, and a bottom surface sloped upward from the supply port to the discharge port. a transfer screw that is installed in the storage tank so as to be substantially parallel to the bottom surface and that transfers the solids supplied from the supply port to the discharge port via the refrigerant pool; and a transfer screw that rotates the transfer screw. and a reversible motor to detect the overload when the solids to be transferred are caught between the inner surface of the storage tank and the transfer screw, the overload is detected by the reversible motor, and the detected signal is The control member is actuated by the control member, the reversible motor is stopped by the control member, and after a certain period of time has elapsed since the stop, the reversible motor is reversed by a predetermined number of rotations to release the biting by the screw, and then the reversible motor is stopped by the control member. A method for releasing an overload on a cooling device, which is characterized in that the cooling device is returned to normal operation by normal rotation after a period of time has elapsed.