JPH0771367A - Liquid level sensor and liquid mixing device using liquid level sensor - Google Patents

Abstract

PURPOSE:To control a liquid level in a mixing container arranged in a multiple liquids (two liquids) mixing device certainly and to improve precision of a mixing ratio. CONSTITUTION:In a container, a pin 451 having one end free to engage with a float to follow displacement of reserved liquid and the other end to engage with an actuator 455 of a sensor main body 457 are provided, and by actuating a sensor by force working in accordance with engagement with the float, supply of the liquid to the container is cut off. Additionally, by supporting the pin 451 by a diaphragm 453 in the neighbourhood of the aforementioned other end, working force of the float is amplified and transmitted to the actuator 455.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level sensor and a multi-liquid mixing device using the same, and is suitable for application to, for example, a two-liquid mixing or coating system.

[0002]

2. Description of the Related Art Conventionally, the internal pressure of a mixing container provided in this type of device is equal to the outlet pressure of a pump serving as a liquid supply means, and the discharge amount of a mixed liquid, for example, a paint gun from a spray gun or the like. Depended on the pressure of the pump and the piping resistance of the liquid supply path. In addition, air with a pressure slightly lower than the outlet pressure of the pump is introduced into the mixing container, and the liquid supply by the pump is stopped by using the increase in the container pressure due to the rise of the liquid level according to the liquid supply The so-called air balance method was adopted.

[0003]

However, in such a system, even if the outlet pressure of the pump fluctuates slightly, the liquid level goes up and down, which makes the control of the liquid level, that is, the amount of liquid storage unstable, resulting in deterioration of mixing accuracy and mixing. There was a problem that pulsation occurred in the liquid. In addition, such a mixing container is equipped with a stirrer for stirring the liquid, which often has a power transmission shaft that penetrates into the container, but the liquid level rises carelessly. Then, the liquid adheres to the packing of the shaft and the like, and if this is a curing agent, the liquid may adhere to the stirrer, causing malfunction of the stirrer. An object of the present invention is to solve these problems and enable the control of the liquid surface with excellent stability and responsiveness, thereby improving the accuracy of the mixing ratio and preventing the occurrence of inconveniences such as malfunctions. And

[0004]

To this end, the liquid level sensor of the present invention comprises a float that follows the displacement of the liquid stored in the container, a sensor body having an actuator that responds to the action of an external force, and the float. A link member having one end engageable with the actuator and the other end for engaging the actuator to exert the external force, and a holding member for holding the link member at a position closer to the other end than the middle thereof. It is characterized by that. Here, the container is used in a sealed state with respect to the atmosphere, the holding member has a diaphragm,
The diaphragm can maintain the sealed state. Further, the multi-liquid mixing device of the present invention is characterized by including such a liquid level sensor and a container for introducing a plurality of liquids and mixing them. Here, it is possible to further include a plurality of liquid supply means for supplying the liquid under pressure to the container, and a means for stopping the supply of the liquid by the plurality of liquid supply means according to the operation of the sensor main body. .

[0005]

In the present invention, the float is disposed in the container, and the sensor is operated by the engagement of the float and the link member with the rise of the liquid level, and the pump is stopped by this. Can be controlled quickly and stably. Further, since the link member is held at a position close to the end portion of the sensor body that engages with the actuator,
Even a weak force such as the action force of the float can be amplified by the lever principle and the sensor can be reliably operated.

The present invention will be described in detail below with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing an example of a schematic configuration of a two-liquid mixing apparatus to which the present invention is applied. In the figure, 1
Reference numerals 00 and 200 respectively denote a main component pump and a curing agent pump in the form of a diaphragm pump, which constitute a plurality of liquid supply means. In this example, the main component pump 100 is a variable displacement type and the curing agent pump 200 is a fixed displacement type. It is as a thing.

A cleaning agent pump 300 constitutes another liquid supply means for supplying a cleaning liquid to the apparatus. 400
Is a mixer for mixing the main agent and the curing agent,
A stirrer 4 for stirring and mixing both agents stored inside
80 and a driving member for driving this, for example, an air motor 490, and the mixed liquid is supplied to a spray gun or the like for coating. 500 is the main agent supplied by the main agent pump 100 or the cleaning agent pump 3
First for selectively passing the cleaning liquid supplied by the
Is a three-way valve unit serving as a flow path switching means of the above, and 550 is a three-way valve unit serving as a second flow path switching means for guiding the liquid introduced from the three-way valve unit 500 to the mixer 400, the drain tank, or the measuring device. Is. Reference numerals 600 and 650 are three-way valve units that perform the same functions as the three-way valve units 500 and 550 with respect to the curing agent and the cleaning liquid, respectively. Reference numeral 700 is a source of pressurized air, and 750 is an opening / closing valve provided in a path for introducing the pressurized air into the mixer 400. Reference numeral 800 denotes a control unit as an input and control means, which controls the operations of the main agent pump 100, the curing agent pump 200, and the cleaning agent pump 300, and the three-way valve 5
The flow path switching operation of 00, 550, 600 and 650 is controlled. In this example, the control unit 800 is composed of a pneumatic circuit.

2 to 4 show a more detailed circuit configuration example of the two-liquid mixing apparatus of the present embodiment.
It is assumed that the flow channel marked with the reference numeral and the flow channel marked with the same reference numeral in other drawings are connected to each other. First, in FIG. 2, reference numerals 711 and 713 are a pressure reducing valve and a pressure gauge, respectively, which are provided in a pressurized air introduction path to a spray gun or the like, and are provided as necessary. 721 and 723
Are a pressure reducing valve and a pressure gauge, respectively, provided in the pressurized air introduction path to the mixer 400 and the direction control valve 865 described later with reference to FIG. Reference numerals 810 and 820 denote directional control valves for outputting a pilot air signal for setting the apparatus of this example in a coating mode and a cleaning mode, respectively, and are three-port valves that are operated by a lever 825 to open and close the introduction path of pressurized air. There is. The lever 825 is at a position PNT at which the directional control valve 810 is opened and the painting mode is set.
And a position CLN in which the directional control valve 820 is opened to set the cleaning mode, and a position OFF in which both are closed are operable. Reference numeral 830 is a directional control valve for outputting a pilot air signal for setting the device of this embodiment to the metering mode, and is a push button operation type normally closed three-port valve. 845 and 855 operate in response to the supply of pilot air output from the painting mode setting directional control valve 810 and the metering mode setting directional control valve 830, respectively, and output pressurized air supplied from the air source 700. It is a 5-port air operated directional control valve. 86
5 operates in response to the supply of the pilot air signal output from the cleaning mode setting direction control valve 830, and the air source 70
It is a 5-port air operated directional control valve that outputs pressurized air supplied from 0.

The pressurized air output from the direction control valve 845 is
It is delivered toward a directional control valve 870 for driving the main agent pump 100 and the hardening agent pump 200, which will be described later with reference to FIG. The directional control valve 855 switches the output destination of the pressurized air according to the presence / absence of the pilot air signal, sets the liquid flow path to the mixer 400 side when there is no signal, and when the signal is present, the meter 560 and Set it to the 660 side. Further, the directional control valve 865 switches the output destination of the pressurized air in response to the supply of the pilot air signal from the directional control valve 820, and when there is no signal, the pressurized air is supplied to the mixer 400 or the like described later with reference to FIG. When the signal is supplied and the signal is present, pressurized air is output to the cleaning agent unit 390.

Next, referring to FIG. 3, a cleaning agent unit 390.
Has a tank that stores the cleaning agent and a pump that is driven in response to the supply of pressurized air, and the tank interior 950 includes three-way valve units 500 and 600 and three-way valve units 550 and 650 in response to the drive. The cleaning agent stored in is discharged.

The three-way valve unit 500 has an air actuator 501 and a three-way valve 503 operated by the air actuator 501. The air actuator 501 has a port CL that receives an air signal from the direction control valve 845 and a port PL that receives an air signal from the cleaning mode setting direction control valve 820, and depending on the reception, the main agent and the cleaning liquid, respectively. The three-way valve 503 is switched such that Similarly, the three-way valve unit 600 also has a directional control valve 8
An air actuator 601 provided with a port HL for receiving an air signal from 45 and a port CL for receiving an air signal from the cleaning mode setting directional control valve 820, and a curing agent or a cleaning agent depending on the received air signal. And a three-way valve 603 for supplying the gas. Three-way valve unit 5 located downstream of the three-way valve unit 500
The air actuator 50 includes an air actuator 551 and a three-way valve 553 operated by the air actuator 551.
51 is a switch of the three-way valve 553 so that the liquid is introduced into the mixer 400 when the air signal is received from the direction control valve 850 to the port MX, and the liquid is introduced into the meter 560 when the air signal is received from the port ME. I do. Three-way valve unit 650 arranged downstream of the three-way valve unit 600
Also regarding the supply path on the curing agent side, the three-way valve unit 550
Similarly, it has an air actuator 651 and a three-way valve 653.

Reference numeral 491 is a speed controller for adjusting the operation of the air motor 490. 950 is a three-way valve unit 500, 600 and a three-way valve unit 550, 65
The back pressure valve is inserted between the back pressure valve and 0, and the configuration and operation thereof will be described later with reference to FIG.

4, reference numeral 880 is a directional control valve for shutting off and supplying pressurized air to the directional control valve 870 according to the presence or absence of a pilot air signal, and 890 is the directional control valve 8.
It is a relay element that supplies pressurized air supplied from 55 to the direction control valve 880 as pilot air according to the operation of the sensor 450, and cuts off the supply when the sensor 450 is not operated. Further, a portion indicated by a broken line frame 900 is a main agent and a curing agent supply section, and a more detailed configuration thereof will be described with reference to FIG.

In FIG. 5, a main agent pump 100 and a hardening agent pump 200 are double-acting diaphragm pumps, which are connected by rods 110 and 210, respectively.
Diaphragms 111, 112 and 211, 212
have. In the figure, the chamber 1 on the right side partitioned by diaphragms 111 and 211 in housings 120 and 220
21 and 221, and the left side chambers 122 and 222 partitioned by the diaphragms 112 and 212, the directional control valve 87.
Air supply / exhaust is alternately performed from 0. Diaphragm 11
The chamber on the left side of 1, 112 is a pump chamber and is connected to the corresponding tank 101, 201 and three-way valve 503, 603. Reference numerals 103 and 203 are check valves that operate to prevent backflow to the tanks 101 and 201 when the main agent and the curing agent are supplied to the three-way valves 503 and 603, and 105 and 205 are the main agent and the curing agent from the tanks 101 and 201. This is a check valve that operates to prevent backflow from the three-way valves 503 and 603 when the agent is introduced. The right chambers 127, 227 defined by the diaphragms 112, 212 are open to the atmosphere via a communication hole (not shown).

In this example, a mechanism 150 for switching the direction of air supply and exhaust of the direction control valve 870 is provided for the main agent pump 100. The mechanism 150 includes a hollow cylinder portion 15 that extends to the right of the housing 120 in the schematic diagram.
1, a rod 153 connected to the rod 110 and sliding inside the cylinder portion 151, and a joint 15 for introducing pressurized air from the air source 700 into the cylinder 151.
5 and joints provided on both sides of the joint 155 with respect to the rod moving direction in order to supply pilot air to the directional control valve 870 to discharge the air according to the position of the rod 153 and switch the supply / exhaust direction of the directional control valve 870. 16
1, 162 and rod 153 to prevent leakage of pressurized air toward joint 161.
V-seal 171 provided on 53 and joint 16
V provided on the rod 153 to prevent leakage in two directions
It has a seal 172 and an adjusting portion 185 (shown by hatching in the figure) that adjusts the diaphragm stroke to make the pump displacement variable.

In the figure, on the left side of the position where the joint 155 is disposed, the sliding of the rod 153 is received, and the joints 155 to 161 are provided with a gap from the rod 153.
A member 181 for guiding air to the cylinder 151 is fixedly provided on the inner wall of the cylinder 151. Further, on the right side of the position where the joint 155 is disposed, a member 182 that similarly receives sliding of the rod 153 and guides air from the joint 155 to 162 through a gap with the rod 153 is provided on the inner wall of the cylinder 151. The member 182 serves as a component of the adjusting portion 185. These members 181 and 182 contact the V seals 171 and 172 provided on the rod 153, respectively, and in this state, the outflow of air to the joints 161 and 162 is sealed, but the members 181 and 182 contact the joints 161 and 162 as the rod 153 slides. When the contact state is released, an air passage reaching the joint 161 or 162 is formed, and pilot air is output to the direction control valve 870.

Reference numeral 183 is a holding member for holding the member 182 and setting the position inside the cylinder. A male screw is provided on the outer periphery of the holding member 183 and is screwed to a female screw provided on the inner wall of the cylinder. Reference numeral 184 denotes an operation member attached to the holding member 182, and these members 182 to 184 integrally form an adjusting portion 185. Then, the operator operates the operation member 1
The position of the member 182 with respect to the cylinder 151 can be adjusted by rotating 84 appropriately and feeding the holding member 183 by an appropriate amount. Then, the output timing of the pilot air changes, and the supply / exhaust switching (switching between the I side and the II side) timing of the directional control valve 870 changes, so that the strokes of the diaphragms 111 and 112 change, and thus the pump It is possible to change the volume, that is, the amount of the main agent mixed.

6 and 7 are explanatory views for explaining the operation of the rod 153 and the mechanism 150. First, FIG. 6 shows a state in which the stroke is maximized. At this time, the end surface of the holding member 183 has an abutting portion 151 in the cylinder.
Abuts A. The upper part of the figure is the chamber 1 of FIG.
22 is exhausted, the chamber 121 is exhausted, the rod 153 moves to the right, and the member 181 and the V seal 171.
This is the state when the contact with is released and the flow path from the joints 155 to 161 is formed as shown in the enlarged portion. At this time, the directional control valve 870 is switched by using the air flowing out from the joint 161 as a pilot, the air is supplied to the chamber 121 of FIG. 5, the chamber 122 is exhausted, and the rod 153 moves to the left. . And
As a result of the movement of the rod 153, the lower portion of FIG.
81 and the V seal 172 are released from the contact, and the joint 1
This shows a state in which a flow path from 55 to 162 is formed, and from this state, the rod 153 moves to the right.

FIG. 7 shows a state in which the stroke is small. In this state, the amount of the member 182 entering the cylinder 151 is small. The upper part and the lower part in the figure are similar to the upper part and the lower part in FIG. 6, respectively, of the rod 153 when the flow path from the joint 155 to 161 and the flow path from the joint 155 to 162 are formed. The position is shown. As is apparent from the comparison between FIG. 7 and FIG. 6, in FIG. 7, the member is located at a position where the contact with the V-seal 172 is released earlier when the rod 153 moves to the left than in the case of FIG. 182 is set. Therefore, at this time, the stroke L2 of the rod 153 is
Is smaller than the stroke L1 in the case of FIG. 6, that is, the pump capacity can be reduced. In the present embodiment, L1 is 7.5 mm and L2 is 1.5 mm, and the stroke, that is, the pump displacement is variable during this period.

FIG. 8 shows an example of the structure of the back pressure valve 950. Here, 951 is a joint 953
Through the directional control valve 855, the main body having a chamber 955 for receiving the pressurized air, 961 and 963 are lid members combined with the main body, and the main agent and the main agent introduced through the joint 965 respectively. It forms a space for receiving the curing agent introduced via 967. Reference numerals 971 and 973 are joints each having a flow passage 971A for flowing out the introduced main agent and a flow passage 973A for flowing out the hardening agent. 981 is a diaphragm, the pressure of the air supplied from the valve 855 (back pressure)
It operates according to the magnitude relation between the supply pressure of the main agent supplied from the pump 100. Reference numeral 983 is a diaphragm that operates similarly to the diaphragm 981 with respect to the curing agent. 9
Reference numerals 91 and 993 are valves attached to the diaphragms 981 and 983. When the supply pressures of the main agent and the curing agent are lower than the back pressure, the flow passages 971A and 973A are opened to supply the pressures of the main agent and the curing agent, respectively. Open greater than back pressure, open channels 971A and 973A.

In this example, pumps 100 and 20
For 0, the pressurized air from the air source 700 is guided as it is through the direction control valve 845, while for the mixer 400 and the back pressure valve 950, the pressure reducing valve 721 is used.
The air depressurized by is supplied via the valve 855. Therefore, the air pressure supplied to the back pressure valve 950 is lower than the predetermined operating pressure (liquid supply pressure) of the pumps 100 and 200, and is substantially equal to the pressure inside the mixer 400. The diaphragm pumps 100, 200 repeat the suction process and the discharge process of the main agent and the curing agent in accordance with the output air from the directional control valve 870. Focusing on the operating pressure curves of these processes, the diaphragm pump 100 in the region where the operating pressure is low, The operation may not be stable due to deformation or the like. Therefore, as in this example, a back pressure valve 950 is provided,
In the liquid supply pressure region below the back pressure, that is, in the region where the operating pressures of the pumps 100 and 200 are not sufficient, and thus the supply pressure or supply amount of the main agent and the curing agent is unstable,
Flow paths 971A and 97 by valves 991 and 993
3A are respectively closed, and the flow paths 971A and 973A are opened only after the pump operating pressure is increased and the supply pressure or supply amount of the main agent and the curing agent is stabilized. The supply amount or mixing ratio of can be kept stable. Further, by providing such a back pressure valve 950, even if the three-way valves 553 and 653 are switched to the pressurized mixer 400 side or to the atmosphere opened metering devices 560 and 660 side, those secondary sides are also provided. The effect of pressure on pumps 100, 200
A stable operation can be performed without affecting the above.

FIG. 9 is a partial sectional view showing an example of the structure of the mixer 400. As shown in the figure, a float 410 is provided inside the mixer, and can be moved up and down along with the shaft 481 of the stirrer 480 combined with the air motor 490 according to the fluctuation of the liquid level. Further, the pin 451 of the sensor 450 is provided so as to be engageable with the float 410, and the engagement position is a desired position where the operation of the pumps 100 and 200 is desired to be stopped,
That is, it can be set according to the desired liquid level to be retained. In this example, the maximum working pressure of the pumps 100 and 200 is
The pressure is set higher than the air pressure supplied to the mixer 400, and liquid level control using the float 410 and the sensor 450 is performed. Therefore, as compared with the structure in which the liquid supply from the pumps 100 and 200 is stopped according to the balance between the internal pressure of the mixer and the liquid supply pressure from the pumps 100 and 200, liquid level control with high responsiveness and stability becomes possible. As a result, a stable mixing ratio can be secured, and the liquid surface is inadvertently raised to cause the packing portion 4 of the shaft 481 to rise.
It is possible to prevent inconveniences such as liquid sticking to 83.

FIG. 10 shows a structural example of the sensor 450 used in this example. The vicinity of the other end of the pin 451 as a link member having one end that engages with the float 410 is the diaphragm 4
A ball 455 that is supported by 53 and that is an actuator of the sensor body 457 at the other end.
Is engaged with. This ball 455 is a float 410
With the engagement of the pin 451 with the diaphragm 453 as a fulcrum, the pin 451 can be retracted into the sensor body 457. A low-pressure air is introduced into the sensor main body 457, and a passage for exhausting (leaking) the low-pressure air is provided, and the passage is closed as the ball 455 retreats. On the other hand, the relay 890 shown in FIG.
7 and is operated by an increase in pressure due to the closing of the passage, supplies pilot air to the directional control valve 880 and cuts off the air supply to the directional control valve 870 to pump 100, 200 as described above. Stop the operation of. In addition,
As the sensor body 457 and the relay 890, for example, a ball leak sensor and a leak sensor relay manufactured by NOK F-Tech Co., Ltd. can be used, respectively. According to this example, the mixer 40 is provided by the provision of the diaphragm 453.
The inside of 0 is hermetically sealed to prevent air leakage from the inside, and the diaphragm 453 prevents the pin 4 from leaking.
By supporting 51 near the other end side from the engaging end with the float 410, the pin 451 can be removed from the float 410.
It is possible to amplify the force received by the liquid and reliably detect the liquid surface.

The operation of the apparatus of this example will be outlined with reference to FIGS. First, the operator sets the lever 825 of FIG. 2 to the PNT side to set the apparatus of this example to the coating mode. That is, the pilot air is supplied to the direction control valve 845 from the direction switching valve 810 according to the setting. Here, if the sensor pin 451 and the float 410 are not engaged, the relay 890 does not output pilot air, and air is introduced into the directional control valve 870 via the directional control valve 880, and the pilot air input from the mechanism 150 is changed. The pumps 100 and 200 are driven accordingly. In addition, the direction control valve 84
The pilot air from 5 is the actuator 501, 60
The three-way valves 503 and 603 are supplied to the input terminals PL and HL of the main component pump 100 and the curing agent pump 20.
From 0 to the back pressure valve 950, and the back pressure valve 950 further forms a flow path to the three-way valves 553 and 653 when the liquid supply pressure is equal to or higher than the back pressure given to the direction control valve 865. To do. Here, if the push button of the directional control valve 830 is not operated, that is, if the measurement mode is not set, the directional control valve 85
5, the input end MX of the actuators 551 and 651
Air is supplied to the three-way valves 551 and 651 to form a flow path toward the back pressure valve 950 and a flow path toward the mixer 400. Therefore the pump 10
The main agent and the curing agent respectively supplied from 0 and 200 are introduced into the mixer 400 through the three-way valves 503 and 553, the back pressure valve 950 and the three-way valves 603 and 653, and are agitated and mixed to be applied for coating. Will be done.

When the push button of the directional control valve 830 is operated and the metering mode is set, air is supplied to the input ends ME side of the actuators 551 and 651 through the directional control valve 855, and the three-way valve 551 is supplied. , 651 form a flow path from the three-way valves 503, 603 toward the measuring instruments 560, 660. Therefore, the main agent and the curing agent supplied from the pumps 100 and 200, respectively, are supplied via the three-way valves 503 and 553, the back pressure valve 950 and the three-way valves 603 and 653, and the measuring instruments 560 and 6 are provided.
Introduced into 60, it will be used for confirmation of the mixing ratio of the apparatus of this example. Note that in the above, the air whose pressure has been reduced by the pressure reducing valve 721 is introduced into the mixer 400 via the direction control valve 865. Also, float 410 and sensor pin 4
Relay 890 outputs pilot air in response to engagement with 51, and air supply to directional control valve 870 is cut off accordingly, and pumps 100, 200 stop.

Next, the operator uses the lever 825 shown in FIG.
By setting to the N side, the apparatus of this example is set to the cleaning mode. That is, the direction switching valve 82 is set according to the setting.
From 0, pilot air is supplied to the directional control valve 865,
The cleaning agent unit 390 is driven according to the air supplied by the direction control valve 865. Further, the pilot air from the directional control valve 820 is supplied to the input ends CL of the actuators 501 and 601, whereby the three-way valves 503 and 603 are supplied.
Is the cleaning unit 390 to the back pressure valve 95.
A flow path toward 0 is formed. At this time, since the back pressure valve 950 is not supplied with air from the direction control valve 865, the flow path toward the three-way valves 553 and 653 is formed as it is. Here, if the push button of the direction control valve 830 is not operated, that is, if it is not set to the measurement mode side,
Actuators 551, 65 via the direction control valve 855
The air is supplied to the input end MX of the 1 and the three-way valve 55
1, 651 is the back presser valve 950 to the mixer 4
Forming a flow path toward 00. Therefore the pump 300
The cleaning agent supplied from is introduced into the mixer 400 via the three-way valves 503, 553, the back pressure valve 950 and the three-way valves 603, 653, and the supply paths of the main agent, the curing agent and the mixed solution thereof are cleaned. become.

When the push button of the directional control valve 830 is operated and the metering mode is set, air is supplied to the input ends ME side of the actuators 551 and 651 through the directional control valve 855, and the three-way valve is supplied. 551 and 651 form a flow path from the three-way valves 503 and 603 toward the measuring instruments 560 and 660. Therefore, the cleaning agent supplied from the pump 300 is introduced into the measuring instruments 560 and 660 through the three-way valves 503 and 553, the back pressure valve 950 and the three-way valves 603 and 653, and it is possible to clean them. . According to the embodiment described above, the mixing of the main agent and the curing agent for coating, the metering of both agents, and the switching of the three-way valve for cleaning the supply path can be performed by a simple operation of operating a lever or a push button. Since this is done, there is no delay as compared with the case where the three-way valves are operated separately, and the operation in each mode can be performed stably. Furthermore, an inexpensive diaphragm pump with no sliding parts is used for the main agent and hardener pumps, and the capacity of one pump (main agent pump) can be changed independently of the other,
And since these pumps are operated synchronously by the air circuit, for example, the diaphragm rods of both pumps are mechanically connected by a link, and the mixing ratio is changed by changing the fulcrum of the pumps, compared to the configuration in which The mechanical load is not applied to the diaphragm, the adjustment of the mixing ratio is easy, and the accuracy is high. Further, the provision of the back pressure valve 950 can further improve the mixing ratio accuracy.

Further, the provision of the sensor 450 enables the liquid level to be quickly detected and controlled, so that the accuracy of the mixing ratio can be improved and the coating material can be prevented from sticking to the stirrer or the packing. Since the spray paint pressure, that is, the discharge amount of the paint can be set independently of the pump pressure, stable coating is also possible. In addition, since the total liquid pressure control circuit is used in the multi-liquid mixing apparatus of the above example, it is possible to avoid a danger such as ignition and realize a safe working environment. The present invention is not limited to the above embodiments, and various modifications can be made.

For example, in the above example, the case where the present invention is applied to a two-liquid mixing device used for coating has been described, but it goes without saying that the present invention can be applied to a multi-liquid mixing device used for other purposes. is there. Further, the configuration of the various liquid supply means is not limited to the diaphragm pump or the like such as the upper side, but a plunger pump, a gear pump, a pressurized container or the like can be used. Further, the means for stabilizing the amount of liquid supplied from the liquid supply pump and the configuration of the mixer or the sensor can be arbitrarily set. For example, for a back pressure valve, the flow path formed,
The number and configuration of valves and diaphragms can be appropriately determined according to the form of the apparatus to be applied or the number of liquids to be supplied. Further, the sensor main body 457 and the relay 890 are not limited to the ball leak sensor and the leak sensor relay as shown in the upper side, and various kinds can be used, and the sensor can be various other than the mixer as in the above example. Of course, it can be applied to a liquid storage container.

[0030]

As described above, according to the present invention,
The float is arranged in the container, and the sensor is activated in response to the engagement between the float and the link member when the liquid level rises, so that the liquid supply to the container is cut off. You will be able to control quickly and stably. Further, since the link member is held at a position close to the end of the sensor body that engages with the actuator, even a weak force such as the acting force of the float can be amplified and transmitted to the actuator. Also, with these,
When applied to a multi-liquid mixing device, it is possible to improve the accuracy of the mixing ratio and prevent the inconvenience caused by the careless rise of the liquid level.

[Brief description of drawings]

FIG. 1 is a schematic view showing a schematic configuration example of a two-liquid mixing apparatus as an embodiment of the apparatus of the present invention.

FIG. 2 is a pneumatic circuit diagram showing a part of a detailed configuration of the present embodiment.

FIG. 3 is a pneumatic circuit diagram showing a part of the detailed configuration of the present embodiment.

FIG. 4 is a pneumatic circuit diagram showing a part of the detailed configuration of the present embodiment.

FIG. 5 is a cross-sectional view showing a more detailed structure of a main agent / curing agent supply section used in this example.

FIG. 6 is an explanatory diagram for explaining the operation of the operation switching / stroke adjusting mechanism in the supply unit.

FIG. 7 is likewise an explanatory diagram.

FIG. 8 is a cross-sectional view showing a configuration example of a back pressure valve used in this embodiment.

FIG. 9 is a partial cross-sectional view showing a configuration example of a mixer used in this example.

FIG. 10 is a cross-sectional view showing a configuration example of a liquid level sensor attached to the mixer.

[Explanation of symbols]

 100 Main Agent Pump 101 Main Agent Tank 111, 112 Diaphragm 150 Operation Switching / Stroke Adjusting Mechanism 185 Control Unit 200 Hardener Pump 201 Hardener Tank 211, 212 Diaphragm 300 Cleaning Agent Pump 350 Cleaning Agent Tank 400 Mixer 410 Float 450 Liquid Level Sensor 490 Air motor 500, 550, 600, 650 Three-way valve unit 560, 660 Measuring instrument 700 Pressurized air source 711, 721 Pressure reducing valve 810, 820, 830, 845, 855, 865, 870, 880 Directional control valve 890 Relay element 900 Main agent / Hardener supply section 950 Back pressure valve 981, 983 Diaphragm

Claims (4)

[Claims] 1. A float that follows displacement of a liquid stored in a container, a sensor body having an actuator that responds to the action of an external force, one end engageable with the float, and one that engages with the actuator. A liquid level sensor comprising: a link member having the other end for acting the external force; and a holding member for holding the link member at a position closer to the other end than the middle thereof. 2. The liquid according to claim 1, wherein the container is used in a closed state with respect to the atmosphere, and the holding member has a diaphragm, and the diaphragm keeps the closed state. Area sensor. 3. A multi-liquid mixing apparatus comprising: a container for introducing a plurality of liquids and mixing them, and the liquid level sensor according to claim 1 or 2. 4. The liquid crystal display device further comprises a plurality of liquid supply means for pumping the liquid toward the container, and a means for stopping the liquid supply by the plurality of liquid supply means in response to the operation of the sensor body. The multi-liquid mixing device according to claim 3, wherein