JP2021088946A - Liquid level control system - Google Patents

Abstract

To provide a liquid level control system which can achieve manpower saving.SOLUTION: A first ball tap 12 which is operated according to change of a liquid level of an adhesive compound in a reservoir part 11 is connected to a first interface valve 29. A first air operate valve 31 connected to the first interface valve 29 is connected to a pump 14. When the liquid level of the reservoir part 11 is lowered to a lower limit, a valve part 26 of the first ball tap 12, the first interface valve 29, and the first air operate valve 31 open and control air is supplied to the pump 14 to supply the adhesive compound to the reservoir part 11. When the liquid level of the reservoir part 11 is risen to an upper limit, the valve part 26 of the first ball tap 12, the first interface valve 29, and the first air operate valve 31 close and supply of the control air to the pump 14 is stopped to stop the supply of the adhesive compound to the reservoir part 11.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid level management system for liquids stored in a storage unit.

In a coating device such as a comma coater that applies an adhesive (adhesive) to a base sheet such as paper or film, an applicator roll with a blade and a dam portion are provided above the backup roll, and the backup roll, Adhesive is stored in the storage part defined by the applicator roll and the dam part, and the adhesive is applied to a base sheet guided by the backup roll with a certain film thickness while scraping off excess adhesive with the applicator roll. Is configured to be coated. In the coating device, in order to apply the adhesive to the base sheet with an appropriate film thickness, it is necessary to keep the height (level) of the liquid level of the adhesive stored in the storage portion at an appropriate position. .. Therefore, the operator monitors the liquid level of the storage unit, and when the liquid level drops below the predetermined height position, the pump is manually operated to replenish the adhesive.

However, since it is necessary for the operator to constantly monitor the liquid level, there is a problem that labor saving is hindered, the burden on the operator is increased, and stable liquid level management cannot be performed. Therefore, a device has been proposed in which the liquid level is monitored by using a ball tap and the change in the liquid level is detected by a flow rate switch or a pressure switch (see, for example, Patent Document 1).

Utility Model Registration No. 3059981

The apparatus disclosed in Patent Document 1 controls the liquid level and can supply or shut off the liquid by opening and closing the automatic valve. However, in the case of specifications that require the supply of a highly viscous liquid using an air drum pump, the pressure of the air that can be supplied or shut off by the ball tap is weak, and the pump cannot be operated. Therefore, when the adhesive is replenished to the storage portion by the air type, the operator still has to manually operate the pump, and it is not possible to save labor. In addition, in a configuration in which changes in the liquid level are detected by electrical signals detected by a flow rate switch or pressure switch, an environment in which a high concentration of organic gas is generated like an adhesive containing an organic solvent as a main component and may explode. , It is pointed out that the safety of use in a humid environment or a dusty environment cannot be ensured.

That is, an object of the present invention is to provide a liquid level management system capable of saving labor.

In order to overcome the above-mentioned problems and achieve the intended purpose, the invention according to claim 1 of the present application is:
It is a liquid level management system for the liquid stored in the storage section.
A pump that is operated by control air to supply liquid to the reservoir,
A ball tap that supplies or shuts off signal air by raising or lowering the float in response to a change in the height of the liquid level.
It is a gist to include an air-operated valve means for supplying or shutting off control air to the pump by supplying or shutting off the signal air.
In this way, since the pump can be operated to supply the liquid to the storage unit in response to the change in the height of the liquid level, the liquid level management can be automated and labor saving can be achieved. In addition, since the air-operated valve means is controlled by a signal air different from the control air that operates the pump, it is possible to accurately control the liquid level by using compressed air with a lower voltage than the control air as the signal air. it can.

The invention of claim 2 is
The gist is that the signal air has a pressure of 0.05 MPa or less.
Since the pressure of the signal air is set to 0.05 MPa or less in this way, the supply and cutoff of the signal air can be accurately controlled even with a small ball tap, and the device can be miniaturized.

The invention according to claim 3 is
The gist is that the control air has a pressure of 0.3 to 0.7 MPa.
Since the pressure of the control air is set between 0.3 and 0.7 MPa in this way, the pump can be efficiently operated to effectively supply the liquid to the storage unit.

The invention according to claim 4 is
The gist is that it is installed in either a dangerous place where an explosive atmosphere may be created or a place where a moisture-proof structure is required in the electrical equipment technical standards.
Since the air-operated valve means and the pump operated by air are used in this way, the liquid level can be safely controlled even in a dangerous place or a place where a moisture-proof structure is required.

According to the present invention, labor saving in liquid level management can be achieved.

It is explanatory drawing which shows the schematic structure of the management system which concerns on embodiment of this invention. It is an air circuit diagram in the management system of an Example.

Next, the liquid level management system according to the present invention will be described below with reference to the accompanying drawings with reference to suitable examples. In the embodiment, the case of the liquid level management system used in the coating apparatus for applying the adhesive to the base sheet will be described.

As shown in FIGS. 1 and 2, the management system of the embodiment is a first ball tap (ball tap) that operates in response to a change in the height of the liquid level of the adhesive stored in the storage portion 11 of the coating device 10. 12, an air-operated valve means 13 that switches between supply and shutoff of controlled air, which is compressed air, according to the operation of the first ball tap 12, and a pump 14 that is operated by the control air to supply an adhesive to the storage unit 11. And. The coating device 10 includes a backup roll 16 that is rotationally driven to guide a base sheet 15 such as paper or film, an applicator roll 17 with a blade located above the backup roll 16, and a backup roll 16. A dam member 18 that is disposed above and defines the adhesive storage portion 11 between the rolls 16 and 17 is provided, and the adhesive is stored in the storage portion 11 and is guided by the backup roll 16. The surface of the base material sheet 15 is coated with the pressure-sensitive adhesive with a constant film thickness while scraping off excess pressure-sensitive adhesive with the applicator roll 17.

As the pressure-sensitive adhesive, one containing an organic solvent such as acrylic or ethyl acetate as a main component is used, and the coating device 10 and the management system are arranged in the explosion-proof area 20 partitioned by the partition wall 19. As the pressure-sensitive adhesive, for example, one having a viscosity of 100,000 poise or more is used, but one having a viscosity other than this or one containing no organic solvent can also be used.
Here, the explosion-proof area is a "dangerous place" (dangerous place that may generate an explosive atmosphere) defined by the factory electrical equipment explosion-proof guideline (International Harmonized Explosion-proof Guideline 2015 (JNIOSH-TR-46: 2015)). Is. Hazardous areas are factories and offices that handle flammable gases and vapors, and create an "explosive atmosphere" that is formed by releasing or leaking into the atmosphere during operation or work and mixing with air. There are so many places that cannot be ignored, and electrical equipment (electrical equipment) becomes the ignition source, and there is a possibility of an explosion accident. In the above guideline, as dangerous places, Zone 0: a place where an explosive atmosphere exists continuously or exists for a long time, Zone 1: a place where an explosive atmosphere may be generated in a normal state, Zone 2 : The explosive atmosphere is classified into three types of places that are not generated in the normal state and exist only for a short time even if they are generated, and the explosion-proof area includes these three types.

The management system of the embodiment includes the pump 14 that supplies the adhesive to the storage unit 11, and the air circuit unit M of the control air that operates the pump 14 and the signal air that operates the air actuating valve means 13. FIG. 2 schematically shows the air circuit unit M, in which the air regulator 24 is connected to the first pipe line 23 connected to the filter regulator 22 connected to the air supply source 21 such as a compressor. The air regulator 24 is connected to the first ball tap 12 via the second pipeline 25. The filter regulator 22 flows the compressed air pressure supplied from the air supply source 21 to the first pipeline 23 as control air adjusted to a control pressure (0.5 MPa in the embodiment) suitable for the operation of the pump 14. Is configured. Further, the air regulator 24 adjusts the pressure of the control air supplied through the first pipeline 23 to a signal pressure (0.01 MPa in the embodiment) that does not hinder the operation of the first ball tap 12 with high accuracy. The signal air is configured to be supplied to the first ball tap 12. The first ball tap 12 includes a valve portion 26 to which the second pipeline 25 is connected to the IN side port 26a, and a float 27 for opening and closing the valve portion 26. The float 27 is a liquid level in the storage portion 11. It is configured to be able to move up and down in response to changes in the height of the. Then, as shown in FIG. 1, the first ball tap 12 opens the valve portion 26 when the float 27 is lowered to the lower limit L as the liquid level of the storage portion 11 is lowered to the height position of the preset lower limit L. The valve is valved, and then the valve portion 26 is closed when the float 27 rises to the upper limit H as the liquid level of the storage portion 11 rises to a preset height position of the upper limit H.

As shown in FIG. 2, the fourth pipeline 28 connected to the OUT side port 26b in the valve portion 26 of the first ball tap 12 is connected to the signal pressure input port 29a of the first interface valve 29. The first interface valve 29 is configured to be opened by supplying the signal air to the signal pressure input port 29a via the fourth pipeline 28. Further, the first pipeline 23 is connected to the IN side port 29b of the first interface valve 29, and the fifth pipeline 30 connected to the OUT side port 29c of the first interface valve 29 is normally closed. It is connected to the signal pressure input port 31a of the first air operating valve 31 of the mold. The first air operating valve 31 is configured to be opened by supplying the control air to the signal pressure input port 31a via the fifth pipeline 30. Further, the first pipeline 23 is connected to the A port 31b of the first air operating valve 31, and the sixth pipeline 32 connected to the B port 31c of the first air operating valve 31 is normally closed, which will be described later. A seventh line 33 connected to the A port 39b of the second air operating valve 39 of the mold and connected to the B port 39c of the second air operating valve 39 is connected to the pump 14. That is, by opening the two air operating valves 31, 39, the control air supplied to the first pipeline 23 is supplied to the pump 14. In the embodiment, the first interface valve 29 and the first air operating valve 31 constitute the air-operated valve means 13.

The pump 14 is a reciprocating pump driven by compressed air, and includes an air motor unit 14a operated by compressed air and a pump unit 14b in which a piston reciprocates by the operation of the air motor unit 14a. The liquid sucked from the suction port 14c of the pump unit 14b is discharged from the discharge port 14d by the reciprocating movement of the piston in 14b. As shown in FIG. 2, in the pump 14, the pump portion 14b is immersed in the adhesive so that the suction port 14c is located near the bottom of the container in the replenishment container 34 in which the adhesive is stored. Further, the pump 14 is arranged so that the other end of the supply hose 35, one end of which is connected to the discharge port 14d, opens above the storage portion 11. That is, the control air is supplied to the air motor unit 14a, and the piston of the pump unit 14b reciprocates, so that the adhesive of the replenishment container 34 is supplied to the storage unit 11 via the supply hose 35.

Here, if the pressure of the signal air for which the supply and the shutoff to the first interface valve 29 (air-operated valve means 13) is switched by opening and closing the valve portion 26 of the first ball tap 12, the pressure of the signal air is too large, the valve portion 26 In order to obtain an urging force for keeping the valve portion 26 in the valve closed state against the pressure of the signal air applied to the valve portion 26 so as to urge the valve portion 26 in the valve opening direction, the valve portion 26 and the float 27 It becomes necessary to increase the size of the mechanism for connecting the floats 27 and the float 27. Further, if the pressure of the signal air is too small, the responsiveness of the first interface valve 29 when the float 27 is lowered and the valve portion 26 is opened is lowered, and accurate opening / closing control cannot be performed. That is, in order to suppress the increase in size of the first ball tap 12 and obtain the practical responsiveness of the first interface valve 29, the pressure of the signal air is a weak pressure of 0.05 MPa or less, for example 0.01 MPa. Is preferable. Further, in order to enhance the responsiveness of the first interface valve 29, it is more preferable that the pressure of the signal air is 0.02 MPa to 0.03 MPa.

Further, if the pressure of the control air that operates the pump 14 is too large, the pump 14 operates excessively and the load becomes large, which causes a failure, and if it is too small, the amount of adhesive consumed by the coating device 10 It becomes impossible to supply the adhesive effectively according to the above. Therefore, in order to operate the pump 14 without burden and effectively supply the adhesive, the pressure of the control air may be between 0.3 MPa and 0.7 MPa, more preferably 0.5 MPa.

The management system of the embodiment is provided with a safety device 36 for stopping the supply of the adhesive by the pump 14 when the float 27 does not rise to the upper limit H due to a failure of the first ball tap 12 or the like. There is. As shown in FIG. 2, the safety device 36 has a second ball tap 37 that can be operated by changing the height of the liquid level of the storage unit 11, and a second interface that opens and closes according to the operation of the second ball tap 37. A valve 38 and a second air operating valve 39 that opens and closes according to the opening and closing of the second interface valve 38 are provided. Specifically, the second ball tap 37 has the same structure as the first ball tap 12, and has a valve portion 41 in which the eighth pipe 40 connected to the second pipe 25 is connected to the IN side port 41a. A float 42 for opening and closing the valve portion 41 is provided, and the float 42 is configured to be able to move up and down in response to a change in the height of the liquid level of the storage portion 11. Then, in the second ball tap 37, the float 42 rises to a limit position HH (see FIG. 1) higher than the upper limit H set so that the float 42 closes the valve portion 26 corresponding to the first ball tap 12. This is configured to close the corresponding valve portion 41. The limiting position HH is set at a height position at which the adhesive stored in the storage unit 11 does not flow out beyond the weir member 18. Further, the second ball tap 37 is configured such that the float 42 opens the valve portion 41 below the limiting position HH.

The ninth pipeline 43 connected to the OUT side port 41b in the valve portion 41 of the second ball tap 37 is connected to the signal pressure input port 38a of the second interface valve 38. Further, the first pipeline 23 is connected to the IN side port 38b of the second interface valve 38, and the tenth pipeline 44 connected to the OUT side port 38c of the second interface valve 38 is A. The sixth pipeline 32 is connected to the port 39b, and the seventh pipeline 33 is connected to the B port 39c. The sixth pipeline 32 is connected to the signal pressure input port 39a of the normally closed second air operating valve 39. .. The second interface valve 38 is configured to be opened by supplying the signal air to the signal pressure input port 38a via the ninth pipeline 43. Further, the second air operating valve 39 is configured to be opened by supplying the control air to the signal pressure input port 39a via the tenth pipeline 44.

[Action of Example]
Next, the operation of the liquid level management system according to the embodiment will be described.

In the coating device 10, when the work of applying the adhesive to the base sheet 15 guided by the backup roll 16 to a predetermined thickness is performed, the liquid level of the adhesive stored in the storage portion 11 is raised. When the float 27 of the first ball tap 12 reaches the lower limit L, the corresponding valve portion 26 opens. When the valve portion 26 is opened, the signal air of 0.01 MPa, in which the pressure of the compressed air supplied from the air supply source 21 is adjusted by the air regulator 24, passes through the valve portion 26 and the fourth pipeline 28. It is supplied to the signal pressure input port 29a of the first interface valve 29, and the first interface valve 29 is opened. As a result, the control air supplied from the first pipeline 23 to the first interface valve 29 is supplied to the signal pressure input port 31a of the first air operating valve 31 via the fifth pipeline 30, and the first 1 The air operating valve 31 is opened. At this time, since the float 42 of the second ball tap 37 is located below the regulation position HH, the second air operating valve 39 is in the valve open state, and the opening of the first air operating valve 31 causes the first pipeline. The 0.5 MPa control air supplied to the 23 is supplied to the air motor portion 14a of the pump 14 via both the air operating valves 31, 39 and the pipelines 32, 32. In the pump 14 to which the control air is supplied, the adhesive in the replenishment container 34 sucked from the suction port 14c by the reciprocating movement of the piston of the pump section 14b is supplied to the storage section 11 via the discharge port 14d and the supply hose 35. To.

When the adhesive is supplied to the storage unit 11 by the pump 14 and the float 27 of the first ball tap 12 reaches the upper limit H as the liquid level in the storage unit 11 rises, the corresponding valve portion 26 The valve is closed, the supply of signal air to the signal pressure input port 29a of the first interface valve 29 is cut off, and the first interface valve 29 is closed. As a result, the supply of control air to the signal pressure input port 31a of the first air operating valve 31 is also cut off, and the first air operating valve 31 is closed. As a result, the supply of the control air to the pump 14 is cut off, the pump 14 is stopped, and the supply of the adhesive to the storage unit 11 is also stopped.

Then, when the liquid level of the storage portion 11 drops until the float 27 of the first ball tap 12 reaches the lower limit L, the valve portion 26 of the first ball tap 12, the first interface valve 29, and the first air operated valve 31 are again opened. By opening the valves respectively, the control air is supplied to the pump 14 and the adhesive is supplied to the storage unit 11.

Here, if for some reason the float 27 of the first ball tap 12 reaches the lower limit L and then does not rise to the upper limit H, the pump 14 continues to supply the adhesive and the liquid in the storage unit 11. The surface rises above the upper limit H. Then, when the liquid level rises to the restricted position HH, the float 42 of the second ball tap 37 reaches the restricted position HH, and the corresponding valve portion 41 closes. As a result, the supply of signal air supplied to the signal pressure input port 38a of the second interface valve 38 via the ninth pipeline 43 is cut off, and the second interface valve 38 is closed. The control air supplied to the signal pressure input port 39a of the second air operating valve 39 is cut off through the tenth pipe line 44, and the second air operating valve 39 is closed. As a result, even when the first air operating valve 31 is in the valve open state, the supply of control air to the pump 14 is cut off, and the liquid level of the storage unit 11 is prevented from rising beyond the limited position HH. be able to. When the float 42 of the second ball tap 37 reaches the restricted position HH, it is possible to adopt a configuration in which an alarm means such as an alarm lamp or an alarm buzzer is activated to notify the operator that an abnormality has occurred. preferable.

In the liquid level management system of the embodiment, the change in the liquid level of the adhesive stored in the storage unit 11 is monitored by the first ball tap 12, and the pump is operated by the operation of the first ball tap 12. Since the adhesive 14 can be operated to supply the adhesive to the storage unit 11, the liquid level management can be automated and labor saving can be achieved. Further, since the first ball tap 12 is configured to supply signal air of 0.01 MPa, which is different from the pressure of the control air that operates the pump 14, the valve portion 26 is closed without enlarging the float 27 or the like. The state can be maintained, and the practical responsiveness of the first interface valve 29 when the valve portion 26 is opened can be ensured. Therefore, the pressure-sensitive adhesive can be effectively supplied to the storage portion 11 where the liquid level has dropped, and the liquid level can be controlled accurately.

In the liquid level management system of the embodiment, the pressure of the signal air supplied to the first ball tap 12 is set to 0.05 MPa or less, so that the signal supplied to the valve portion 26 even if it is a small first ball tap 12. The valve portion 26 can be opened and closed with high accuracy against the pressure of air, and the device can be miniaturized. Further, since the pressure of the control air for operating the pump 14 was set between 0.3 and 0.7 MPa, the pump 14 was efficiently operated according to the change in the liquid level in the storage unit 11 and adhered. The agent can be effectively supplied to the storage unit 11. Further, as the pump 14 that supplies the adhesive to the storage unit 11, a pump that is operated by control air is adopted, and an air-operated valve that is operated by signal air as a valve that controls the supply and shutoff of control air to the pump 14. Since the means 13 is adopted, the liquid level can be safely managed even if the adhesive is placed in the explosion-proof area 20 where the coating device 10 for applying the adhesive containing the organic solvent as the main component is applied to the base sheet 15. ..

[Change example]
The present application is not limited to the configuration of the above-described embodiment, and other configurations may be appropriately adopted.
1. 1. In the embodiment, as the first ball tap, the valve portion is configured so that the float closes at the upper limit and opens at the lower limit, but the valve portion is configured to close at the lower limit and open at the upper limit. When the first ball tap configured in this way can be adopted, the liquid level in the storage portion is managed in the same manner as in the embodiment by using a normally open type valve as the first air operating valve. be able to.
2. In the embodiment, a safety device including a second ball tap, a second interface valve, and a second air operated valve is provided, but the safety device can be omitted.
3. 3. In the embodiment, the air-operated valve means is composed of the first interface valve and the first air-operated valve, but in the configuration in which the safety device is omitted, the air-operated valve means is configured only from the first air-operated valve. A configuration can be adopted in which the valve portion of the first ball tap is connected to the signal pressure input port of the first air operated valve by a pipeline. Further, even when the air-operated valve means is configured from only the first air-operated valve, the above 1. The configuration of the modified example of can be adopted.
4. In the embodiment, the management system is arranged in the explosion-proof area, but the management system can also be installed in an area (location) other than the explosion-proof area. For example, flammability, which is a "dangerous place" (dangerous place that may generate an explosive atmosphere) specified in the factory electrical equipment explosion-proof guideline (International Harmonized Explosion-proof Guideline 2015 (JNIOSH-TR-46: 2015)). It can be installed in a dust place or an explosive dust place. The flammable dust place and the explosive dust place are classified in the factory electrical equipment explosion-proof guideline. Zone 20: A place where dust is cloud-like in the air and exists continuously, for a long period of time, or frequently, Zone 21: Locations that can sometimes be formed in the air in the form of dust clouds during normal operation, Zone 22: During normal operation, they are unlikely to be formed in the form of dust clouds in the air and were generated. It is a place that is short even if.
In addition, the management system is, for example, "Interpretation of technical standards for electrical equipment" (revised on October 1, 2018), which explains the "Ministerial Ordinance for Establishing Technical Standards for Electrical Equipment" (Technical Standards for Electrical Equipment) stipulated by the Ordinance of the Ministry of Economy, Trade and Industry. ), The low-voltage wiring equipment can be installed in a place with a lot of warm air (Article 1, Item 27 of the same interpretation) or a place with water (Article 1, Item 26 of the same interpretation). Here, in the above interpretation, the place where there is a lot of warm air is a place where it is required to use a place having a moisture-proof structure capable of preventing the intrusion of moisture in the wiring equipment for low voltage.
5. In the air circuit section shown in FIG. 2, a control air supply system to the pump is separately provided, and a hand valve capable of switching between supply and cutoff of control air is provided in the supply system, and the pump is manually operated by an operator. It is possible to adopt a configuration that operates to supply the adhesive of the replenishment melter to the storage unit.

11 Reservoir, 12 1st ball tap (ball tap), 13 Pneumatic valve means 14 Pump, 20 Explosion-proof area (dangerous place that may create an explosive atmosphere)
27 float

Claims (4)

It is a liquid level management system for the liquid stored in the storage section.
A pump that is operated by control air to supply liquid to the reservoir,
A ball tap that supplies or shuts off signal air by raising or lowering the float in response to a change in the height of the liquid level.
A liquid level management system comprising: an air-operated valve means for supplying or shutting off control air to the pump by supplying or shutting off the signal air. The liquid level management system according to claim 1, wherein the signal air has a pressure of 0.05 MPa or less. The liquid level management system according to claim 1 or 2, wherein the control air has a pressure of 0.3 to 0.7 MPa. The invention according to any one of claims 1 to 3, wherein the facility is installed in a dangerous place where an explosive atmosphere may be generated or in a place where a moisture-proof structure is required in the technical standards for electrical equipment. Liquid level management system.

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