JPH09257545A - Liquid level control device of paste receiving tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a liquid level of melting paste without being influenced by paste vapor or the like, and maintain it constant by supplying paste to a paste receiving tank by melting solid paste by a heating means on a storage tank inside bottom surface when a temperature becomes equal to or lower than a prescribed temperature in a prescribed height from a paste receiving tank bottom surface. SOLUTION: A control circuit 8 being a heating control means keeps a temperature of melting paste L in a paste receiving tank 32 in an almost preset value (for example, 150 deg.C) by opening and closing a heater 34 by a detecting temperature of a thermocouple 81. Since this melting paste L is periodically supplied to a half-split chopstick packing product, its liquid level lowers, and the lower end (the temperature detecting end) 821 of a thermocouple 82 arranged in a prescribed height from a paste receiving tank bottom surface 32a, is exposed from the melting paste L, and a temperature lowers. Then, the control circuit 8 melts solid paste M by turning on a heater 52 on a storage tank inside bottom surface 51a when a temperature of the thermocouple 82 becomes less than a preset value (for example, 75 deg.C), and supplies it to the paste receiving tank 32 from a paste supply passage 53. Therefore, a liquid level of the melting paste L of the paste receiving tank 32 is kept constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level control device for maintaining a constant liquid level in a glue receiving tank for storing molten glue, and particularly to a highly reliable liquid level which does not cause malfunction due to vapor adhesion of molten glue. The present invention relates to a control device.

[0002]

2. Description of the Related Art As a sensor for detecting a liquid level in a liquid level control device, conventionally, a sensor for detecting a vertical movement of a float, a sensor for detecting conduction between the tips of electrode rods, a light transmission or reflection is used. Things are known.

[0003]

However, industrial glue generally contains a synthetic resin material as a main component and solid glue at 100 ° C. to 20 ° C.
It is used by melting it at 0 ℃.
Bad conditions such as high viscosity and generation of glue vapor overlapped. Under the circumstances, in the float type, there is a possibility that adhesive glue vapor may adhere to the mechanical operating portion to cause malfunction, and further, a relatively large sensor installation space is required. Even in the optical system, it was difficult to detect the liquid level well because the detection window was clouded by the glue vapor. Further, the molten glue is non-conductive, and liquid level detection using an electrode type sensor or the like cannot be used.

The present invention overcomes the above-mentioned problems and has a compact shape and is capable of accurately detecting the liquid level of molten glue and maintaining the liquid level constant without being affected by glue vapor or the like. An object is to provide a liquid level control device for a receiving tank.

[0005]

In order to achieve the above-mentioned object, the present invention provides a glue receiving tank for storing a molten paste, a storage tank for storing a solid paste, and a storage tank for storing the paste. Heating means attached to the tank to melt a part of the solid paste, and flowing the molten paste into the paste receiving tank; and temperature detecting means arranged at a predetermined height from the bottom surface of the paste receiving tank, And a heating control unit that operates the heating unit when the temperature detected by the temperature detection unit becomes equal to or lower than a predetermined temperature. Claim 2
The invention of the liquid level control device for a glue receiving tank according to claim 1,
The temperature detecting means is composed of a thermocouple, and the temperature detecting end of the thermocouple is located at the predetermined height. The invention of the liquid level control device for a glue receiving tank according to claim 3 is
In Claim 1 or 2, the bottom face of a storage tank inclines toward the glue supply port, and the melted glue heated and melted by the said heating means provided in the said bottom face is said glue supply port along the said bottom face. Further, the adhesive is supplied into the adhesive receiving tank through the adhesive supply port.

According to the first aspect of the present invention, when the liquid level of the molten paste falls below a predetermined height, the temperature detecting means is exposed to the outside of the molten paste and is kept at the outside temperature, so that the detected temperature is It drops rapidly and falls below a predetermined temperature. Then, the heating means is operated by the heating control means to melt a part of the solid paste and cause it to flow into the paste receiving tank. The liquid level of the molten glue in the glue receiving tank rises due to the inflow of new molten glue. When the liquid level becomes equal to or higher than a predetermined height, the temperature detecting means is again immersed in the molten paste, and the detected temperature rapidly rises. When the detected temperature is equal to or higher than the predetermined temperature, the heating control unit stops the operation of the heating unit, the melting of the solid paste is stopped, and the supply of the molten paste into the paste receiving tank is stopped. In this way, the liquid level of the molten glue in the glue receiving tank is kept constant near the predetermined height.

When a thermocouple is used as the temperature detecting means as in the second aspect of the invention, since there is no moving part, there is no fear of failure, and the elevation of the liquid level can be detected easily and accurately. When the bottom surface of the storage tank is inclined toward the glue supply port as in the invention described in claim 3, when the solid glue near the bottom surface in the storage tank is heated by the heating means and melted, it melts. The glue is smoothly supplied into the glue receiving tank through the glue supply port.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the liquid level control device according to the present invention is applied to a gluing device for continuous chopsticks will be described in detail below. With reference to FIGS. 1 and 2, the continuous wrapping chopsticks 2 will be described below. Of the resin films that extend in the left-right direction in the figure in a strip shape, the lower film 22 is substantially U-shaped with the film surface protruding in a rectangular shape at intervals in the longitudinal direction. It becomes a storage part P'having a cross section, and the disposable chopsticks S are inserted in each of these storage parts P '. Then, the upper film 21 having the same width is adhered and joined to the lower film 22 from above so that each storage portion P ′ forms a closed space, and
The upper and lower films 21, 22 are provided between the respective storage parts P '.
Form a connecting portion 23 that closely connects the front and rear storage portions P '. As described above, the continuous chopsticks containing the disposable chopsticks S are usually cut at the connecting portion 23 after being delivered to the user. Then, each of the separated storage parts P '(one disposable chopstick package P) is glued to the main body container T (for example, a tray in which rice is packed). The liquid level control device of the glue receiving tank used for this gluing is the present invention.

Prior to the description of the liquid level control device for the glue receiving tank, a mechanism for pasting the disposable chopstick package P on the main body container T will be outlined. In FIG. 3, the continuous-pack chopstick 2 advances to a position on the guide rollers 63 and 64 so that the storage portion P ′ protruding in a convex shape faces upward, and half-turns by the guide roller 64 to the positioning drum 1. Sent. The positioning drum 1 faces the cutting device 71 arranged on the right side, and below the positioning drum 1, a glue receiving tank 32 containing melted glue (hereinafter, referred to as molten glue) is arranged. A tray stack (not shown) is provided on the left side of the positioning drum 1, and among the trays stacked on the tray stack, the lowermost tray T is sequentially supplied onto the conveying section 75 which is in the intermittent movement form of the suction conveyor 74. To be done. The lever 41 for transferring the packaged product sends the packaged product P to which the glue has been applied to the side surface of the tray T and adheres and fixes the packaged product to the side surface of the tray T.

The positioning drum 1 shown in FIG. 3 is a cylindrical body having an outer peripheral width smaller than that of the continuous chopsticks 2 so that the continuous chopsticks 2 may protrude on both sides (perpendicular to the plane of the paper). It is designed to rotate. On the outer periphery of the positioning drum 1, elongated recesses 11 are formed at regular intervals. The recess 11 has a rectangular cross-sectional shape and fits into the storage portion P ′ of the continuous-pack chopsticks 2 as the positioning drum 1 rotates. A plurality of suction holes for vacuum suction are opened in each recess 11, and a deep groove 12 is formed at an intermediate position of each recess 11. Continuous wrapped chopsticks 2 pulled out from the guide roller 64
In the uppermost position of the positioning drum 1, the respective storage portions P ′ protruding from the film surface are sequentially received in the recess 11. Then, in the process of being received in the recess 11, the films 21, 22
Is appropriately expanded and contracted so that the space between the front and rear storage parts P'is corrected to a constant space between the recesses 11. The continuous chopsticks 2 in which the respective storage portions P ′ are received and positioned in the recesses 11 are sent to a position facing the cutting device 71 in the next process as the positioning drum 1 rotates. The cutting device 71 includes an air cylinder 711.
A cutting blade 714 is provided at the tip of a rod 712 extending from the holder via a holder 713. The cutting blade 714 advances its cutting edge into the deep groove 12 on the outer circumference of the positioning drum 1 as shown in FIG. 3, divides the continuous chopsticks 2 at the connecting portion 23 (FIG. 2), and wraps each one individually. Item P (1 piece of disposable chopstick packaging). The separated packaged product P is held in the recess 11 by vacuum suction from the suction hole, rotates together with the positioning drum 1, and passes through the lowest position. The swing arm 31 of the glue supply device 3 is attached to the package P that has passed through the lowest position.
The molten glue L in the glue receiving tank 32 is attached by the operation of. After that, the package P with the molten glue is adhered and fixed to the side surface of the tray T by the lever body 41.

In this way, the melted glue L in the glue receiving tank 32 is consumed and the liquid level thereof is lowered, but the liquid level is kept constant by the liquid level control device of the glue receiving tank according to the present invention.

First, the equipment around the glue receiving tank relating to the liquid level control of the glue receiving tank will be described. The glue receiving tank 32 is provided below the positioning drum 1. A heater 3 is provided in the bottom of the glue receiving tank 32.
4 is buried. The heater 34 extends in the axial direction of the positioning drum 1 and can keep the adhesive paste L in a molten state at about 100 ° C to 200 ° C. Adjacent to the glue receiving tank 32, there is provided a storage tank 51 connected to the glue receiving tank 32 by a glue supply path 53 (glue supply port) (FIG. 6). In the storage tank 51, a solid paste M which is a raw material serving as a resin adhesive is stored. Solid paste M
Is a hot melt agent (made by Saiden Chemical Co., Ltd., trade name: Cybinol, model number: HM-P-27) formed by molding a synthetic resin material into a rectangular plate piece, and is inclined downward toward the glue supply path 53. A large number of layers are stacked on the bottom surface 51a of the storage tank 51. A heater 52 as a heating means is embedded in the bottom wall of the storage tank 51. The heater 52 is a storage tank 51
The solid paste M located in the lower layer of the inside can be heated and melted. When the solid paste M is heated by the heater 52, it melts to become a molten paste L, and the molten paste L flows along the inclined bottom surface 51a of the tank and then flows into the paste receiving tank 32 via the paste supply passage 53. .

In the glue receiving tank 32, in addition to the heater 34 described above, a thermocouple 81 for detecting the temperature of the molten glue L is inserted from the side surface into the bottom wall. Further, a thermocouple 82, which is fixed to a support (not shown) and extends downward from the upper opening of the glue receiving tank 32, serves as temperature detecting means for liquid level detection, and its temperature detecting end (lower end) 8
21 is arranged at a predetermined height h from the bottom surface 32a in the tank. These thermocouples 81 and 82 and the above heaters 3
Reference numerals 4 and 52 are connected to a control circuit 8 which is a heating control means having a built-in CPU. Control energization.

7 and 8 show control flowcharts of the control circuit. FIG. 7 shows the temperature control procedure of the molten glue L in the glue receiving tank 32. In step 101, the detection signal of the thermocouple 81 is read, and in the following step 102, when the detected temperature is lower than the set value (for example, 150 ° C.). Turns on the heater 34
(Step 103). On the other hand, the above step 102
If the detected temperature is 150 ° C or higher, the heater 34 is turned off.
F (step 104). Thus, by turning the heater on and off at a temperature of 150 ° C, the molten glue L
Keep the temperature at 150 ° C, which is almost the set value. The set value is not limited to 150 ° C. as long as it is a temperature that can secure the molten paste L.

FIG. 8 shows an example of the procedure for controlling the liquid level in the heating control means for the molten paste L. In step 201, the detection signal of the thermocouple 82 is read, and when the detected temperature is lower than the set value of, for example, 75 ° C., the heater 5 serving as a heating means.
2 is turned on (steps 202 and 203), and the heater 52 is turned off when the temperature is 75 ° C. or higher (step 20).
4).

As described above, when the melted glue L is periodically supplied to the package P by the swing arm 31, the liquid level of the melted glue L gradually decreases. In the present embodiment, the support shaft 33 is arranged between the side wall of the glue receiving tank 32 and the support column 321 provided in the tank so as to be parallel to the central axis 13, and the support shaft 3
The swing arm 31 is fixed to 3 (FIG. 5). One end of the support shaft 33 is connected to the pinion 35, and the rack 36
Meshes. The rack 36 is fixed to the tip of a piston rod 38 extending from the cylinder 37, and the lower surface portion is supported by a guide roller 39. When the rack 36 is in the retracted position, each swing arm 31 pivots counterclockwise in FIG. 4 and the whole is immersed in the melt glue L (state in FIG. 5). Then, when the package P held on the positioning drum 1 reaches a predetermined position, the rack 36 advances. Along with this, each swing arm 31 turns clockwise,
As shown in FIG. 4, the melted glue L is advanced to the outside, and the tips 311 of the respective arms abut the package P. In this way, the molten glue L at the end 311 of each arm is supplied to the package. A plurality of swing arms 31 are provided, and molten glue is attached and supplied to a plurality of locations in the longitudinal direction of the package P, respectively.

Thus, the liquid level of the molten glue L in the glue receiving tank is lowered and the tip of the thermocouple 82 is exposed from the molten glue L. As a result, the temperature of the thermocouple 82 is the outside air temperature (-50 ° C).
˜50 ° C.) and falls below the set value of 75 ° C.
Then, the heater 52 is turned on. Due to the heating of the heater 52, the solid paste M near the storage tank bottom surface 51a near the heater 52 gradually starts to melt. Then, the melted glue L melted
Flows out along the inclined surface of the storage tank and enters the glue receiving tank 32. Due to such a phenomenon, the liquid level of the molten glue L in the glue receiving tank 32 rises and its height exceeds h. Then, the temperature detecting end 821 of the thermocouple 82 is dipped in the molten paste L again. When the temperature detecting end 821 is immersed in the molten paste L, the temperature detected by the thermocouple 82 rises sharply and exceeds 75 ° C. Along with this, the heater 52 is turned off. The melting of the solid paste M is stopped, and the outflow of the molten paste L into the paste receiving tank 32 is stopped. As described above, the liquid level control of the above-mentioned molten paste is repeated, the liquid level of the molten paste L in the paste receiving tank 32 is kept constant, and the solid paste M other than the necessary amount is maintained in its original shape. In this embodiment, a thermocouple is used as the temperature detecting means, but a temperature detecting means such as a thermistor (resistance temperature detector) or bimetal can be used instead of the thermocouple. This is because these temperature detecting means also have a simple structure and few failures.

According to such a liquid level control device for the glue receiving tank, the liquid level of the molten glue L in the glue receiving tank 32 is maintained at a substantially constant value h, and the amount of the molten glue L in the glue receiving tank 32 becomes excessive. A situation in which the swing arm 31 cannot supply glue to the package P by the swing arm 31 is prevented. Further, conventionally, it has been considered difficult to control the liquid level of the molten paste L in the paste receiving tank 32, and the solid paste M is sufficiently charged in batches into the paste receiving tank 32 to melt it. Therefore, at the end of daily operation, waste such as discarding a large amount of melted glue that is easily oxidized and deteriorated occurs. However, in the present embodiment, only the required solid glue is always melted and automatically replenished, so that the work is easy and the solid glue is not wasted. At the end of the operation, most of the solid paste M remaining in the storage tank 51 is prevented from melting, and most of the solid paste M can be used next time.

Further, when the thermocouple 82 serving as the temperature detecting means is used for detecting the liquid level in the glue receiving tank 32, the thermocouple is a simple temperature sensor based on the electromotive force effect, so that there is no moving part and its structure is simple. Also, the outer peripheral surface can be protected by a protective tube, which is basically not prone to error and does not break. Moreover, since the thermocouple is small, it can be installed compactly. As a matter of course, the situation in which the glue vapor adheres to the mechanical operation portion and the detection window as in the conventional case and the detection becomes impossible, and the thermocouple 82 can achieve accurate liquid level detection for a long period of time. In addition, the glue receiving tank 3
The liquid level control device of No. 2 is usually subjected to vibrations from other machines around it and must detect the liquid level under this adverse condition. The thermocouple 82 as a means has an advantage that it is not affected by them. As described above, the present embodiment is characterized in that the thermocouple (or thermistor or bimetal), which is the temperature detecting means originally used only as the temperature sensor, is used uniquely and effectively as the liquid level detection. There is. Further, the thermocouple has been conventionally used to measure a temperature range of a certain range, but here it is characterized in that it is used to determine whether a set value is exceeded or not exceeded.

In the present invention, the present invention is not limited to the above-described embodiment, but can be variously changed within the scope of the present invention depending on the purpose and application. For example, the heaters 34 and 52 are turned on excessively.
In order to avoid -OFF, hysteresis characteristics may be given at ON and OFF. It is not always necessary to connect the storage tank 51 and the glue receiving tank 32 with the glue supply path 53, and a glue feeding port is provided on the bottom wall of the storage tank 51, and the molten glue L is introduced into the glue receiving tank 32 from this glue feeding port. You may make it supply by dripping directly. The values of 75 ° C. and 150 ° C. in this embodiment can be changed by design. Of course, the present invention is not limited to the solid paste M in the present embodiment, and various solid paste types can be adopted, and the paste receiving tank 32 can be used.
The packaged product P to which the molten glue L of is adhered is not limited to the disposable chopsticks packaged product as an example, and various packaged products such as spoons and straws and the product itself (without a packaging film) are applicable depending on the application. become.

[0021]

As described above, the liquid level control device for the glue receiving tank of the present invention has a structure with few failures and can be made compact, and moreover, the liquid level of the molten glue can be accurately detected and It exhibits excellent effects such as maintaining a constant level.

[Brief description of drawings]

FIG. 1 is a cutaway plan view of a continuous-pack chopstick.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged side view of an essential part of a gluing device using the liquid level control device of the present invention.

FIG. 4 is a cross-sectional view of a glue supply device using the liquid level control device of the present invention.

FIG. 5 is a vertical cross-sectional view of a glue supply device using the liquid level control device of the present invention.

FIG. 6 is a cross-sectional view of a glue receiving tank and a storage tank provided with a liquid level control device according to an embodiment of the present invention.

FIG. 7 is a control flowchart of the control circuit according to the embodiment of the present invention.

FIG. 8 is a control flowchart of the control circuit according to the embodiment of the present invention.

[Explanation of symbols]

 32 glue receiving tank 51 storage tank 51a bottom surface 52 heater (heating means) 53 glue supply path 71 cutting device 8 control circuit (heating control means) 82 thermocouple (temperature detection means) 821 temperature detection end L melted glue M solid glue

Claims (3)

[Claims] 1. A glue receiving tank for storing molten paste, a storage tank for storing solid paste, and a storage tank attached to the storage tank to melt a part of the solid paste, and the melt paste into the paste receiving tank. Heating means for inflowing, temperature detecting means arranged at a predetermined height from the bottom surface of the glue receiving tank, and heating control for operating the heating means when the temperature detected by the temperature detecting means falls below a predetermined temperature. A liquid level control device for a glue receiving tank, comprising: 2. The liquid level control device for a glue receiving tank according to claim 1, wherein the temperature detecting means is composed of a thermocouple, and a temperature detecting end of the thermocouple is located at the predetermined height. . 3. The bottom surface of the storage tank is inclined toward the glue supply port, and the melted glue heated and melted by the heating means provided near the bottom surface reaches the glue supply port along the bottom surface. The liquid level control device for a glue receiving tank according to claim 1 or 2, wherein the liquid is supplied into the glue receiving tank through the glue supply port.