JP2018099654A - Liquid supply system using syringe pump, and method for supplying liquid to syringe pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid supply system using a syringe pump, in which a liquid filling amount is accurate, and which avoids overflow of an ejection amount of a liquid ejected from an ejection unit at an initial operation.SOLUTION: A liquid supply system 1 includes: a syringe pump 11 for supplying a liquid to an ejection unit 10; a liquid supply unit 20 for supplying the liquid to the syringe pump 11; a first piping unit 12 for supplying the liquid from a liquid supply unit 20 side to the syringe pump 11; and a first valve 13 disposed at a position in front of the syringe pump 11 of the first piping unit 12. The liquid supply unit 20 includes: a tank 21 for storing the liquid to be supplied to the syringe pump 11; an auxiliary pump 22 for delivering the liquid in the tank 21 toward the syringe pump 11; a second piping unit 23 for supplying the liquid from the auxiliary pump 22 to a first piping unit 12 side; a second branch piping unit 24 branched from the second piping unit 23 in order to return the liquid to the tank 21; and a second valve 25 disposed in the second branch piping unit 24.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid supply system using a syringe pump and a liquid supply method to the syringe pump.

When pressure is applied to the liquid supplied to the syringe pump to supply the liquid and the syringe pump is filled with liquid, the pressure of the liquid in the syringe pump and the pipe between the syringe pump and the spray gun is also liquid. The pressure is the same as the supply pressure (also referred to as accumulated pressure).
When the operation of the spray gun is started in this state, there is a problem that the liquid ejection amount becomes excessive because the liquid pressure is high due to pressure accumulation in the initial operation of the spray gun.
Therefore, in Patent Document 1, after the syringe pump is filled with liquid, the syringe pump is operated so as to increase the stroke internal volume of the syringe pump so that the pressure of the liquid becomes a predetermined pressure, thereby absorbing the accumulated pressure. Has been done.

JP 2009-131747 A

  In the method of Patent Document 1, since the liquid pressure becomes a predetermined pressure, it is possible to avoid an increase in the amount of liquid ejected at the initial stage of operation of the spray gun, but the liquid is filled more with the liquid supply pressure. This does not eliminate the liquid filling amount.

  The present invention has been made in view of such circumstances, and the liquid filling amount using a syringe pump is more accurate, and the liquid ejected from the ejection portion that ejects the liquid, such as a spray gun, is used. An object of the present invention is to provide a liquid supply system and a liquid supply method to a syringe pump that can avoid an increase in the amount of ejection in the initial stage of operation.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) The liquid supply system of the present invention is a liquid supply system using a syringe pump, and the liquid supply system supplies the liquid to the ejection part that ejects the liquid, and supplies the liquid to the syringe pump. A first pipe part that supplies the liquid to the syringe pump from the liquid supply part side, and a first valve provided at a position in front of the syringe pump of the first pipe part, The liquid supply unit includes a tank that stores the liquid supplied to the syringe pump, an auxiliary pump that sends the liquid in the tank toward the syringe pump, and the liquid from the auxiliary pump to the first piping unit side. A second pipe part for supplying the liquid, a second branch pipe part branched from the second pipe part and returning the liquid to the tank, and a second bar provided in the second branch pipe part And Breakfast, is equipped.

(2) In the configuration of the above (1), the second piping part includes a pressure reducing valve, and the pressure reducing valve is provided closer to the first piping part than a position where the second branching pipe part is branched. Yes.

(3) In the configuration of (1) or (2), a control unit that controls the liquid supply system is provided, and the control unit drives the syringe pump and the auxiliary pump to supply the liquid to the syringe pump. When filling, the first valve is opened and the second valve is closed. After the syringe pump is filled with the liquid, the syringe pump and the auxiliary pump are stopped, and the second valve is stopped. And a part of the liquid sent out from the tank is returned to the tank to reduce the pressure of the liquid sent out from the tank.

(4) In the configuration of (1) or (2), the apparatus includes a plurality of the liquid supply units and a switching valve to which the liquid supply units are connected, and the first piping unit is connected to the switching valve. In addition, each of the second piping parts is connected to the switching valve, and the first piping part and each of the second piping parts are connected via the switching valve.

(5) In the configuration of (4), a control unit that controls the liquid supply system is provided, and the control unit switches one of the second piping units by switching the switching valve. The auxiliary supply of the syringe pump and the used liquid supply unit is controlled by using the liquid supply unit connected to one pipe unit and having the second pipe unit connected to the first pipe unit as the used liquid supply unit. When the pump is driven and the syringe pump is filled with the liquid, the first valve is opened and the second valve of the used liquid supply unit is controlled to be closed, and the syringe pump is filled with the liquid. After that, the syringe pump and the auxiliary pump of the used liquid supply unit are stopped, the second valve of the used liquid supply unit is controlled to be opened, and the tank of the used liquid supply unit is controlled. A portion of the liquid fed from returning to the tank of the used liquid supply unit, reducing the pressure of the liquid fed from the tank of the used liquid supply portion.

(6) In the configuration of (3) or (5), when the liquid is ejected from the ejection unit, the control unit performs control to close the first valve and drives the syringe pump.

(7) The liquid supply method of the present invention is a liquid supply method to a syringe pump, which is sent out from a tank that stores liquid at the time of liquid filling of the syringe pump with an auxiliary pump, and after filling the syringe pump with liquid, A part of the liquid sent out from the tank is returned to the tank, and the pressure of the sent out liquid is reduced.

  According to the present invention, the amount of liquid filling using a syringe pump is more accurate, and it is avoided that the amount of liquid ejected from an ejection part that ejects liquid, such as a spray gun, at the initial stage of operation increases. A liquid supply system and a liquid supply method to a syringe pump can be provided.

It is a figure which shows the structure of the liquid supply system of embodiment which concerns on this invention. It is a figure for demonstrating the flow which fills the syringe pump of embodiment which concerns on this invention with a liquid. It is a figure for demonstrating the process after filling the syringe pump of embodiment which concerns on this invention with a liquid. It is a figure which shows the structure of the modification of the liquid supply system of embodiment which concerns on this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing a configuration of a liquid supply system 1 according to an embodiment of the present invention.

  As shown in FIG. 1, a liquid supply system 1 according to an embodiment of the present invention includes a syringe pump 11 that supplies liquid to an ejection unit 10 that ejects liquid such as paint, and a plurality of liquids that supply liquid to the syringe pump 11. A liquid supply unit 20.

  Since the syringe pump 11 may have a general configuration, illustration is omitted. However, for example, a cylinder, a piston having a through hole for supplying a liquid disposed in the syringe, and a piston for moving the piston And a drive unit such as a servo motor, and a first piping unit 12 for supplying a liquid described later is connected to the through hole of the piston.

  The ejection unit 10 is, for example, an automatic spray gun for receiving the liquid supplied from the liquid supply system 1 and spraying the liquid onto the object to be coated. It selects suitably.

  In addition, the automatic spray gun etc. which are used for the ejection part 10 may be general, and the liquid receiving port of the ejection part 10 and the liquid outlet of the syringe pump 11 are connected by the liquid supply piping 15.

  In addition, the liquid supply system 1 includes a first piping unit 12 that supplies liquid to the syringe pump 11 from the liquid supply unit 20 side, and a position in front of the syringe pump 11 that is on the liquid supply unit 20 side of the first piping unit 12. The first valve 13 provided and the first pipe part 12 provided at the position closest to the liquid supply part 20, which of the plurality of liquid supply parts 20 is to be supplied to the syringe pump 11 is selected. And a switching valve 14 for this purpose.

As shown in FIG. 1, the plurality of liquid supply units 20 have the same configuration.
Specifically, the liquid supply unit 20 includes a tank 21 that stores liquid supplied to the syringe pump 11, an auxiliary pump 22 that sends the liquid in the tank 21 toward the syringe pump 11, and a first pipe from the auxiliary pump 22. A second piping part 23 for supplying liquid to the part 12 side, a second branching pipe part 24 branched from the second piping part 23 and returning the liquid to the tank 21, and a second branching pipe part 24 provided in the second branching pipe part 24 And a valve 25.

  In this embodiment, a diaphragm pump is used as the auxiliary pump 22 as shown in FIG. 1. However, the auxiliary pump 22 is not limited to the diaphragm pump, and is a pump of another type. May be.

The first piping unit 12 is connected to the switching valve 14, and each second piping unit 23 of the plurality of liquid supply units 20 is connected to the switching valve 14.
That is, the liquid supply part which supplies the liquid to the syringe pump 11 by the state which has connected the 1st piping part 12 and each 2nd piping part 23 via the switching valve 14, and switches the switching valve 14. Twenty selections can be made.

The liquid supply unit 20 includes a pressure reducing valve 26 provided in the second piping unit 23 and a manual valve 27 provided in the second branch piping unit 24.
Specifically, the pressure reducing valve 26 is provided on the first pipe part 12 side from the position where the second branch pipe part 24 is branched, and for example, the liquid pumped out from the auxiliary pump 22 at 0.5 MPa is set to 0. The pressure is reduced to about 3 MPa.
The manual valve 27 is always opened when the liquid supply system 1 is used. For example, the manual valve 27 is a valve that is manually closed only when it is necessary to close it for maintenance or the like. It is provided at a position closer to the second piping part 23 than the second valve 25.

A more detailed configuration will be described while describing the operation of the liquid supply system 1 having the above configuration.
In the present embodiment, the liquid supply system 1 is not shown in the figure, but includes an input device (for example, a PC) for inputting painting conditions and the like, and a control unit of the input device controls the liquid supply system 1. It also functions as a control unit for controlling.
However, it is not necessary to use a PC-type input device as the control unit of the liquid supply system 1, and the input device may be changed as appropriate.

First, when the operation is started, a control unit (not shown) that controls the liquid supply system 1 performs a process of switching the switching valve 14 in accordance with the input operating conditions, and the plurality of liquid supply units 20 are controlled. One of the second piping parts 23 is connected to the first piping part 12 via the switching valve 14, and the liquid supply part 20 having the second piping part 23 connected to the first piping part 12 is now used. Control to use the liquid supply unit to be used.
In addition, since the selected use liquid supply part is one liquid supply part 20 of the several liquid supply part 20, below, the same code | symbol as the liquid supply part 20 is used as the use liquid supply part 20. FIG.

FIG. 2 is a view for explaining the flow of filling the syringe pump 11 with liquid, and FIG. 3 is a view for explaining the processing after filling the syringe pump 11 with liquid.
2 and 3 are diagrams in which the liquid supply units 20 other than the liquid supply unit 20 as the selected use liquid supply unit 20 are omitted from the liquid supply unit 20 illustrated in FIG. is there.

  When the liquid supply unit 20 to be used as the liquid supply unit 20 is selected by switching the switching valve 14, the control unit next supplies a line indicated by a thick arrow as shown in FIG. Execute the air bleeding operation.

  However, when the supply of liquid from the selected use liquid supply unit 20 has been performed last time, the liquid exists in the line indicated by the thick arrow, and the liquid is supplied to the syringe pump 11. This operation is not necessary because it is not filled.

Specifically, in the present embodiment, a normally open air operated valve is used as the second valve 25, and a normally closed air operated valve is used as the first valve 13. Control air is sent to the first valve 13 and the second valve 25 to control the first valve 13 to be opened and the second valve 25 to be closed.
And although illustration is abbreviate | omitted, the ejection line (liquid channel | path) provided in the ejection part 10 is opened, and the air of the line shown by the thick arrow is discharged | emitted.
When the discharge of air in the line indicated by the thick arrow ends, the control unit closes the ejection line provided in the ejection unit 10 and ends the air bleeding operation.

When the air bleeding control for discharging the air (air bleeding operation) is completed, the control unit then drives the auxiliary pump 22 of the syringe pump 11 and the used liquid supply unit 20 to supply liquid to the syringe pump 11. Control to fill.
Specifically, the piston of the syringe pump 11 is driven in the direction of filling the liquid, and operating air of about 0.5 MPa is supplied to the auxiliary pump 22 so as to send the liquid from the tank 21 toward the syringe pump 11 side. Take control.
In this embodiment, since the auxiliary pump 22 is a diaphragm pump, the liquid is sent out at the same pressure (about 0.5 MPa) as that of the operating air.

The open / close state of the first valve 13 and the second valve 25 when the syringe pump 11 is filled with liquid may be the same as the open / close state when the air is vented.
Therefore, the control unit drives the auxiliary pump 22 of the syringe pump 11 and the used liquid supply unit 20 to fill the syringe pump 11 with the liquid, and also opens the first valve 13 and the second valve. Control is performed so that 25 is closed.

The liquid pumped out at 0.5 MPa by the auxiliary pump 22 is decompressed to about 0.3 MPa by the decompression valve 26 and filled into the syringe pump 11.
When the filling of the liquid into the syringe pump 11 is completed, the control unit stops the supply of operating air to the auxiliary pump 22 and stops the driving of the auxiliary pump 22.

  In this way, when not only filling with the suction force of the syringe pump 11 but also assisting the suction by sending it out with the auxiliary pump 22, the liquid becomes difficult to be exposed to negative pressure, and bubbles or the like are generated in the liquid. Can be suppressed.

That is, if the filling is performed only by the suction force of the syringe pump 11, the inside of the second piping portion 23 and the first piping portion 12 is in a strong negative pressure state.
If it does so, the gas melt | dissolved in the liquid will appear as a bubble, and if the liquid containing such a bubble is ejected from the ejection part 10 and a liquid is sprayed on a to-be-coated object etc., a coating state will worsen because of a bubble.

  However, as in this embodiment, if the liquid is sent to the syringe pump 11 side with the auxiliary pump 22 in accordance with the suction force of the syringe pump 11, the liquid can be prevented from being exposed to a strong negative pressure state. The generation of bubbles is suppressed, and a good liquid can be sprayed on the object to be coated.

In addition, in order to suppress generation | occurrence | production of such a bubble etc., suppressing the suction force of the syringe pump 11 is also considered, but when doing so, when the viscosity of the liquid is high, the syringe pump 11 is filled with the liquid. It will take time.
However, if the auxiliary pump 22 is used as in the present embodiment, the liquid can be filled without generating bubbles even if the suction force of the syringe pump 11 is not suppressed. This time can be shortened.

  On the other hand, when the filling of the syringe pump 11 is finished, the liquid is filled at a pressure of about 0.3 MPa. Therefore, when the ejection of the liquid from the ejection unit 10 is started in this state, The amount of liquid ejected at the initial stage of spraying until the pressure settles to a predetermined pressure (for example, the state of atmospheric pressure) increases, and there is a possibility that uneven coating or the like occurs.

  Therefore, in the prior art, after filling the syringe pump with liquid so that the pressure is about atmospheric pressure, the pressure of the liquid is lowered by moving the piston of the syringe pump to the side that expands the volume in the syringe. .

Certainly, although the pressure of the liquid can be lowered by the operation performed by the prior art, this operation originally fills the filling amount of the liquid that is overfilled as a pressurized filling state at the atmospheric pressure state. It does not reduce the filling amount when it is done.
For this reason, in the operation of the prior art, there is a difference between the filling amount of the liquid filled in the syringe pump and the filling amount originally intended to be filled.

Therefore, after the syringe pump 11 sucks the liquid (that is, after the syringe pump 11 is filled with the liquid), the control unit stops the auxiliary pump 22 of the syringe pump 11 and the used liquid supply unit 20 to use the used liquid. Control air supplied to the second valve 25 of the supply unit 20 is stopped, and the second valve 25 is opened.
Then, the liquid that could not return to the tank 21 due to the check structure of the auxiliary pump 22 can return to the tank 21 through the second piping part 23.

  Since the first valve 13 remains open, when the control unit performs control to open the second valve 25, both the first valve 13 and the second valve 25 are opened, as shown in FIG. As described above, when the liquid flows in the direction of the thick arrow and the syringe pump 11 is filled with the liquid, a part of the liquid sent out from the tank 21 of the use liquid supply unit 20 returns to the tank 21 of the use liquid supply unit 20. .

Therefore, as described above, the liquid sent out from the tank 21 of the used liquid supply unit 20 and filled at about 0.3 MPa is reduced to the same atmospheric pressure as the pressure in the tank 21.
The reduced pressure in this case does not change the filling volume of the syringe pump 11, and is a reduced pressure by returning the liquid that has been filled by the pressure back to the tank 21. Therefore, the filling amount of the liquid in the syringe pump 11 is It becomes the filling amount that was originally intended to be filled, and there is no difference from the filling amount that was originally intended to be filled as in the prior art, and an accurate filling amount can be obtained.

And a control part performs control which makes a liquid eject from the ejection part 10 next, after the process to pressure-reduce is complete | finished.
When the liquid is ejected from the ejection unit 10, the control unit stops the supply of control air supplied to the first valve 13, performs control to close the first valve 13, and drives the syringe pump 11. Then, control for supplying the liquid from the syringe pump 11 to the ejection unit 10 is executed.

  As described above, the liquid supply method to the syringe pump 11 is sent out from the tank 21 that stores the liquid by the auxiliary pump 22 when the syringe pump 11 is filled with the liquid, and after the syringe pump 11 is filled with the liquid, the liquid is supplied from the tank 21. By returning a part of the liquid to the tank 21 and reducing the pressure of the delivered liquid, the filling amount of the liquid filled in the syringe pump 11 can be made accurate, and the operation of the ejection unit 10 is started. In the initial stage, it is possible to suppress an increase in the amount of ejected liquid.

  As mentioned above, although the liquid supply system 1 of this invention was demonstrated based on specific embodiment, this invention is not limited to specific embodiment.

FIG. 4 is a diagram showing a configuration of a modified example of the liquid supply system 1 according to the embodiment of the present invention.
In the above-described embodiment, the liquid supply system 1 having the plurality of liquid supply units 20 has been described. However, as illustrated in FIG. 4, the liquid supply system 1 includes only one liquid supply unit 20. Also good.

In this case, as shown in FIG. 4, the switching valve 14 (see FIG. 1) may be omitted and the first piping unit 12 and the second piping unit 23 may be directly connected.
When there is one liquid supply unit 20, the control unit only needs to control the switching of the switching valve 14, and basically the liquid supply unit used in the above embodiment. Control similar to that described for control 20 may be performed.

  Moreover, although the said embodiment demonstrated the case where the air operated valve driven by control air was used for the 1st valve 13 and the 2nd valve 25, the 1st valve 13 and the 2nd valve 25 are electrically controlled type | molds. There is no particular limitation as long as the above-described control can be performed.

  Thus, the present invention is not limited to a specific embodiment, and modifications and improvements as appropriate are also included in the technical scope of the present invention. Is clear from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 Liquid supply system 10 Injection part 11 Syringe pump 12 1st piping part 13 1st valve 14 Switching valve 15 Liquid supply piping 20 Liquid supply part 21 Tank 22 Auxiliary pump 23 2nd piping part 24 2nd branch piping part 25 2nd valve 26 Pressure reducing valve 27 Manual valve

Claims (7)

A liquid supply system using a syringe pump,
The syringe pump for supplying the liquid to an ejection part for ejecting the liquid;
A liquid supply unit for supplying liquid to the syringe pump;
A first piping section for supplying the liquid to the syringe pump from the liquid supply section side;
A first valve provided at a position in front of the syringe pump of the first piping part,
The liquid supply unit is
A tank for storing the liquid supplied to the syringe pump;
An auxiliary pump for sending the liquid in the tank toward the syringe pump;
A second piping part for supplying the liquid from the auxiliary pump to the first piping part side;
A second branch pipe branched from the second pipe and returning the liquid to the tank;
A liquid supply system comprising: a second valve provided in the second branch pipe section. The second piping part is provided with a pressure reducing valve,
2. The liquid supply system according to claim 1, wherein the pressure reducing valve is provided closer to the first piping portion than a position where the second branch piping portion is branched. A controller for controlling the liquid supply system;
The controller is
When the syringe pump and the auxiliary pump are driven to fill the syringe pump with the liquid, the first valve is opened and the second valve is closed.
After the syringe pump is filled with the liquid, the syringe pump and the auxiliary pump are stopped, the second valve is opened, and a part of the liquid sent out from the tank is returned to the tank. The liquid supply system according to claim 1, wherein the pressure of the liquid sent out from the tank is reduced. A plurality of the liquid supply units;
A switching valve to which the liquid supply unit is connected,
The first piping unit is connected to the switching valve, each second piping unit is connected to the switching valve, and the first piping unit and each second piping unit are connected via the switching valve. The liquid supply system according to claim 1, wherein the liquid supply system is connected. A controller for controlling the liquid supply system;
The controller is
The liquid supply part having the second pipe part connected to the first pipe part by connecting one of the plurality of second pipe parts to the first pipe part by switching the switching valve. Perform control to use liquid supply unit,
When the auxiliary pump of the syringe pump and the used liquid supply unit is driven to fill the syringe pump with the liquid, the first valve is opened and the second valve of the used liquid supply unit is closed. Control
After the syringe pump fills the liquid, the syringe pump and the auxiliary pump of the used liquid supply unit are stopped, and the second valve of the used liquid supply unit is controlled to open, and the used liquid supply unit A part of the liquid sent out from the tank is returned to the tank in the used liquid supply unit, and the pressure of the liquid sent out from the tank in the used liquid supply unit is reduced. Item 5. The liquid supply system according to Item 4.   6. The liquid according to claim 3, wherein when the liquid is ejected from the ejection part, the control unit performs control for closing the first valve and drives the syringe pump. 6. Supply system. A method for supplying liquid to a syringe pump,
When the syringe pump is filled with liquid, it is sent out from the tank that stores the liquid with an auxiliary pump, and after the syringe pump is filled with liquid, a part of the liquid sent out from the tank is returned to the tank, and the sent out A liquid supply method characterized by reducing the pressure of the liquid.

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