JPH0446867Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention is a device for detecting damage to screens such as wire mesh or perforated plates used for sieving powder and granular materials and filtering liquids containing solids. Regarding.

<Prior art> A sieving machine is a device that supplies a substance to the top surface of one or more screens and vibrates or rotates the screen to determine whether or not the supplied substance passes through the screen. Depending on the crab,
It separates (classifies) substances into multiple groups.

In addition to the above-mentioned types of filtration for separating solids in liquid, there are also methods that simply fix a screen and allow the fluid to pass through, and methods that forcefully discharge solids that have accumulated on the screen. be.

In any case, things are separated into things that pass through the screen and things that don't, so if the screen is damaged, for example, if the wire mesh is torn, things that shouldn't pass through will pass through. , and normal sieving or filtration cannot be performed.

Particularly during the final process, which affects product quality, damage to the screen of the sieving machine is a serious problem.
It will have fatal consequences.

For this reason, conventionally, workers have periodically inspected and confirmed the presence or absence of damage to the screen by visually or tactilely using their hands.

<Problem that the invention attempts to solve> However, in the conventional method as mentioned above,
The problem was that since inspections were carried out at regular intervals, delays in detecting abnormalities were unavoidable.

If you want to detect it as early as possible,
There was no other option than increasing the frequency of inspections, but in order to do inspections, it was necessary to stop the operation of the sieving machine, and the time required for one inspection also varied depending on the size and opening of the screen. It can take quite a long time, so there is a limit.

In particular, in continuous production plants, the frequency of inspections has a significant impact on productivity, as stopping operations not only wastes the time required for inspection, but also the time required to stop and restart operations. It was hot too.

Furthermore, when the opening of the screen is small (1 mm or less), a wire mesh is usually used, but because the wire diameter is small, it is difficult to visually detect damage to the wire mesh, and in particular, it is difficult to detect damage to the wire mesh by visual inspection. It is almost impossible to do so if the operator is using the tactile sense of his/her hand, which requires skill.

In addition, if an abnormality is found during regular inspections, the processed materials from the time of the screen breakage to the time of discovery have not been properly sieved or filtered, so reprocessing is necessary. However, since it is not clear at what point the abnormality occurred, all items after the previous inspection were reprocessed.

Therefore, there was a problem in that the time and cost burden associated with this was enormous.

Moreover, if a sieving machine or the like on the production line was used for reprocessing, production would have to be stopped during this time, resulting in a considerable amount of damage.

SUMMARY OF THE INVENTION In view of these conventional problems, it is an object of the present invention to provide a screen damage detection device that can quickly and automatically detect the occurrence of screen damage in a sieving machine or the like.

<Means for Solving the Problems> In order to achieve the above-mentioned object, in the present invention, a screen that separates substances into multiple types depending on whether or not they pass through the eyes is provided with a The structure includes a high-frequency detection sensor that detects high-frequency waves.

<Function> In the above configuration, the high frequency detection sensor installed near the screen detects the high frequency (breaking sound) that is generated when the screen is damaged and is not felt by the human body. (including metal fittings, etc.).

Therefore, a signal from this sensor may be used to issue an alarm, stop operation, or the like.

<Example> An example of the present invention will be described below based on FIGS. 1 to 4, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a plan view of the main part of Fig. 1, and Fig. 3 a and b are a-a and b-b of Fig. 2. The cross-sectional view, FIG. 4, is a circuit diagram of the amplifier and alarm device.

An example in which the screen damage detection device according to the present invention is applied to a sieving machine will be described with reference to FIGS. 1 to 3.

The sieving machine 1 has a wire mesh 2 serving as a screen in the middle of the main body, and a wire mesh mounting frame 3 fixed to the inner side wall of the main body.
It is sandwiched and fixed by wire mesh holding fittings 4 and stretched.

At one end of the upper side of the wire mesh 2, there is provided a supply port 5 for raw materials, etc., which is open toward the top. Also,
On the other end side, there is provided a wire mesh upper substance recovery port 6 that opens downward, and a wire mesh 2 is provided in the vicinity thereof.
On the lower side, there is provided a metal mesh lower substance recovery port 7 which also opens downward. Further, the sieving machine 1 is supported by a spring 8 and a vibrator 9
It is designed to be vibrated by.

In the high frequency detection sensor 10 according to the present invention, a hole 11 for inserting the sensor 10 is formed in the wire mesh holding fitting 4, so that the sensor 10 can come into contact with the wire mesh 2 through the hole 11. The other end of the sensor 10 is attached to the sensor 1 by a sensor holding fitting 12.
0 holds the wire mesh 2, and the wire mesh holding bracket 4
Fixed.

The output end of the sensor 10 is connected via an amplifier 13 to
It is connected to the alarm device 14.

Here, raw materials, etc. are supplied via the supply port 5 to the upper side of the wire mesh 2 which is excited by the vibrator, and while being excited together reach the material recovery port 6 on the upper side of the wire mesh at the other end.
It is collected through this.

In addition, the substance that is supplied from the supply port 5 side at one end on the wire mesh 2 and moves to the lower side of the wire mesh 2 through the holes of the wire mesh 2 while reaching the material collection port 6 on the upper side of the wire mesh is transferred to the material collection port on the lower side of the wire mesh 2. Collected from 7.

The high frequency waves generated in these processes are transmitted through the wire mesh 2 and detected by the sensor 10. The signal caught by the sensor 10 is first guided to the amplifier 13 and amplified, and then sent to the alarm device 14.

Referring to FIG. 4, amplifier 13 and alarm device 14
The mechanism is explained in detail.

First, the preamplifier 15 amplifies the detected high frequency. Then, the next detection unit 16 detects the frequency in the sound range that occurs when the wire mesh 2 is damaged, that is, it detects the sound waves that are generated when the wire mesh 2 is broken, and which is as large as possible and is generated at a time other than when the screen is broken. Select only the sound range with low sound pressure and let it pass. Then, the next variable amplifier section 1
Amplify with 7.

In other words, the generated frequency varies depending on the wire diameter and material of the wire mesh, and is not constant, but according to experiments, when the wire mesh opening is 40 meshes (opening approximately 0.4 mm), the wire diameter is approximately
In the case of 0.3mm, the sound waves in the 50 to 200KHz range were relatively strong, but in the 50 to 100KHz range, we were able to capture more than just the sound of damage, so we had to
Detects and amplifies only the 200KHz frequency.

The comparison section 18 compares the detected and amplified signal to determine whether the sound pressure level of the signal exceeds a reference level value preset by the comparison voltage adjustment section 19. When the reference level value is exceeded, the contact 20a of the switch section 20 is closed.

Note that a level meter 21 is provided so that the magnitude of the signal input from the sensor can be visually observed from the outside.

The contact 20a of the switch section 20 serves as a switch that operates a separately provided relay 22. Once the contact 20a closes, the relay 22 operates, and the contact 23 of the relay 22 activates the relay 22. The movement is self-maintaining.

Therefore, the signal generated due to the breakage of the screen is extremely instantaneous, the sound pressure level sensed by the sensor 10 decreases, and the contact 20a of the switch section 20 of the amplifier 13
Even if the relay 22 is opened, the relay 22 continues to operate, so the other contact 24 of the relay 22 that operates at the same time continues to close, allowing current to flow through the buzzer 25, and an alarm will not occur unless the reset button 26 is manually pressed. will continue.

As a result, instead of the conventional inspections that were periodically performed by workers, automatic monitoring can now be performed at all times.

In this embodiment, the sensor is fixed to the wire mesh mounting frame, but it may be fixed directly to the wire mesh. The point is that the screen only needs to be able to sense the high frequency generated when it is damaged, and in extreme terms, it does not need to be in close contact with the screen.

Also, according to experiments, when the wire mesh wire diameter was approximately 0.3 mm, it was possible to catch the breakage sound at a distance of approximately 1.5 m from the sensor, but the number of sensors installed depends on the screen size, wire diameter, sensor It may be increased depending on the sensitivity.

Further, although a buzzer is used to warn in the event of an abnormality, the present invention is not limited to this, and it goes without saying that a lamp or other alarm device may be used.

In addition, in order to automate and unattend the work, it is necessary not only to install a device that issues an alarm using a screen damage detection signal, but also to install an automatic stop device in addition to the alarm device, and to go even further, to Either switch the destination of the substances coming out of the separator, etc. to another line, or
It is preferable to install a system in which the flow of raw materials supplied to the sieving machine or the like is switched to a backup sieving machine.

<Effects of the invention> The present invention has been described above, and has particularly remarkable effects as described below, and has extremely great industrial utility value.

(1) According to the present invention, there is no need to stop operation to inspect the screen of the sieving machine, and there is no need for inspection work, so the operating rate of the sieving machine is significantly improved.

(2) Since the occurrence of screen damage can be detected automatically and instantly, it can be dealt with promptly, so there is no need to re-screen the material that has been sieved using a screen, reducing the cost of reprocessing. There is no need to increase production costs, and there is no need to stop production for long periods of time for reprocessing.

[Brief description of the drawings]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a plan view of the main part of Fig. 1, Fig. 3a is a sectional view taken along line aa in Fig. 2, and Fig. 3b is a b-b in Figure 2
The cross-sectional view, FIG. 4, is a circuit diagram of the amplifier and alarm device. 1...Sieving machine, 2...Wire mesh, 10...High frequency detection sensor, 13...Amplifier, 14...Alarm device.

Claims (1)

[Scope of utility model registration request] A screen damage detection device characterized in that a high frequency detection sensor for detecting high frequency waves generated due to damage to the screen is provided near a screen that separates a substance into a plurality of parts depending on whether the substance passes through the eyes or not. .