JP2016037003A - Liquid transfer apparatus and liquid transfer apparatus chamber cleaning method - Google Patents

Abstract

A liquid transfer apparatus capable of efficiently removing residual liquid in a chamber and preventing the residual liquid from dripping when the chamber is detached from an anilox roller.
An anilox roller (5) for supplying a transfer liquid composed of one of varnish and ink to a sheet (2) and a chamber (6) for storing the transfer liquid in cooperation with the anilox roller (5). A feed pump 15 is connected to the chamber 6 via a feed passage 12 and discharges any one of the transfer liquid and other fluids to the feed passage 12. A return pump 19 that sends the contents of the chamber 6 to the return tank via the return passage 14, a portion downstream of the feed pump 15 in the feed passage 12, and a portion upstream of the return pump 19 in the return passage 14. A bypass passage 18 that connects the two and a bypass valve 20 that opens and closes the bypass passage 18 are provided.
[Selection] Figure 1

Description

  The present invention relates to a liquid transfer apparatus for applying varnish or ink to a sheet or web and a method for cleaning a chamber for the liquid transfer apparatus.

  As a conventional liquid transfer apparatus of this type, there is one described in Patent Document 1, for example. The liquid transfer apparatus disclosed in Patent Document 1 is of a chamber coater type, is equipped in a printing machine, and applies varnish to a sheet that is a printing medium. The liquid transfer apparatus includes an anilox roller for supplying varnish to the sheet and a chamber for supplying varnish to the anilox roller. The chamber is configured to store varnish in cooperation with the anilox roller. In this chamber, when changing the kind of varnish or when performing maintenance, the varnish is collected from the inside and then cleaned with a cleaning liquid.

  In performing the maintenance of the chamber, the chamber is detached from the anilox roller. At this time, if varnish or cleaning liquid remains in the chamber, these residual liquids hang down in the printing press. For this reason, conventionally, in order to prevent the residual liquid from remaining in the chamber, air was supplied into the chamber to push out the residual liquid from the chamber.

JP 2006-56055 A

  However, the liquid in the chamber cannot be completely removed by simply sending air into the chamber when discharging the liquid from the chamber. For this reason, in the conventional liquid transfer apparatus, when the chamber is detached from the anilox roller, the residual liquid sometimes drips into the printing press.

  The present invention has been made to solve such a problem, and is capable of efficiently removing the remaining liquid in the chamber, and the liquid transfer apparatus in which the remaining liquid does not drip when the chamber is detached from the anilox roller. It is an object of the present invention to provide a method for cleaning a chamber for a liquid transfer apparatus.

  In order to achieve this object, a liquid transfer apparatus according to the present invention includes an anilox roller for supplying a transfer liquid composed of one of varnish and ink to a sheet, and a transfer in cooperation with the anilox roller. A chamber for storing liquid, a feed pump connected to the chamber via a feed passage and discharging any one of a transfer liquid and other fluids to the feed passage, and a return passage for the contents of the chamber A return pump for feeding to the return tank via the bypass passage, a bypass passage for connecting a portion of the feed passage downstream from the feed pump, and a portion of the return passage upstream of the return pump, and the bypass And a bypass valve for opening and closing the passage.

  The present invention is characterized in that, in the above invention, the feed passage is connected to a lower portion of the chamber, and the return passage is connected to an upper portion of the chamber.

  The present invention further includes a transfer liquid tank in which the transfer liquid is stored in the invention, wherein the suction portion of the feed pump is connected to the transfer liquid tank via a suction passage, and the suction passage is connected to the transfer liquid tank. A transfer liquid suction passage having a tip opened in the liquid and provided with a first flow path switching valve in the middle, and is connected to the downstream side of the first flow path switching valve in the middle of the transfer liquid suction path. And an air suction passage provided with a second flow path switching valve in the middle thereof, the tip of which is released into the atmosphere.

  The present invention further includes a cleaning liquid tank in which the cleaning liquid is stored in the above invention, and a tip is in the liquid of the cleaning liquid tank in the middle of the transfer liquid suction passage and downstream of the first flow path switching valve. And a cleaning liquid suction passage having a third flow path switching valve in the middle thereof is connected.

  The liquid transfer device chamber cleaning method according to the present invention is a liquid transfer device chamber cleaning method for cleaning a chamber using the bypass passage according to the invention, wherein the bypass valve is open. The feed pump is stopped and the return pump is operated.

In the present invention, when the return valve operates while the bypass valve is open and the feed pump is stopped, the transfer liquid flows back through the passage for supplying the transfer liquid to the chamber, and passes through the bypass passage. Discharged. For this reason, the transfer liquid is discharged not only from the transfer liquid outlet of the chamber but also from the transfer liquid inlet.
Therefore, according to the present invention, it is possible to provide a liquid transfer apparatus that can efficiently remove the remaining liquid in the chamber and that does not spill when the chamber is detached from the anilox roller.

It is a piping diagram for demonstrating the washing | cleaning method of the liquid transfer apparatus which concerns on this invention, and the chamber for liquid transfer apparatuses. It is process drawing for demonstrating the cleaning method of a chamber. It is a piping diagram for demonstrating a 1st varnish collection | recovery step. It is a piping diagram for demonstrating a 2nd varnish collection | recovery step. It is a piping diagram for demonstrating a washing | cleaning liquid supply step. It is a piping diagram for demonstrating a washing | cleaning-liquid circulation step. It is a piping diagram for demonstrating a 1st washing | cleaning liquid collection | recovery step. It is a piping diagram for demonstrating a 2nd washing | cleaning liquid collection | recovery step. It is a block diagram which shows the structure of a control system. 4 is a flowchart for explaining a method of cleaning a chamber for a liquid transfer apparatus according to the present invention.

Hereinafter, an embodiment of a liquid transfer apparatus and a method for cleaning a chamber for a liquid transfer apparatus according to the present invention will be described in detail with reference to FIGS.
A liquid transfer apparatus 1 shown in FIG. 1 is used in a printing machine (not shown), and applies a varnish to a sheet 2 that is a printing medium. The sheet 2 is conveyed by the impression cylinder 3 of the printing press. A transfer cylinder 4 is in contact with the impression cylinder 3, and an anilox roller 5 is in contact with the transfer cylinder 4.

  A large number of concave grooves (not shown) are formed on the outer peripheral surface of the anilox roller 5 to hold the varnish. The varnish is supplied by a chamber 6 connected to the outer peripheral surface of the anilox roller 5. The varnish supplied to the anilox roller 5 is transferred from the anilox roller 5 to the transfer cylinder 4 and further transferred from the transfer cylinder 4 to the sheet 2 passing between the impression cylinder 3 and the transfer cylinder 4.

  The chamber 6 has a structure for storing varnish in cooperation with the anilox roller 5, and is connected to a varnish supply device 11 described later. Although not shown, the chamber 6 has one side portion (upper end portion in the chamber 6 shown in FIG. 1) supported by the printing press frame via a support shaft so as to be swingable. It is connected to. The support shaft is provided in parallel with the axis of the anilox roller 5. The drive device swings the chamber 6 with respect to the anilox roller 5 and removes it from the anilox roller 5 during maintenance of the chamber 6 or when replacing the chamber 6. As described above, when the chamber 6 is detached from the anilox roller 5 or when the type of varnish to be used is changed, a cleaning liquid is passed through the chamber 6 instead of the varnish, and the chamber 6 is cleaned. These varnish supply function and cleaning function are realized by a varnish supply device 11 connected to the chamber 6.

  The varnish supply device 11 has a feed passage 12 connected to the transfer liquid inlet 6 a at the lower end of the chamber 6 and a return passage 14 including a liquid receiving tank 13 positioned below the chamber 6. The feed passage 12 is a passage for supplying fluid such as varnish and cleaning liquid to the chamber 6, and is connected to the discharge portion 15 a of the feed pump 15. The feed pump 15 is constituted by a diaphragm pump. In this embodiment, a supply valve 16 is provided between the feed pump 15 and the chamber 6, and an accumulator 17 and a bypass passage 18 are connected between the supply valve 16 and the chamber 6. ing.

  The bypass passage 18 communicates the feed passage 12 and the return passage 14. More specifically, the bypass passage 18 connects a portion of the return passage 14 upstream of the later-described return pump 19 to a portion of the return passage 14 downstream of the feed pump 15. A bypass valve 20 that opens and closes the bypass passage 18 is provided at an intermediate portion of the bypass passage 18. Operations of the feed pump 15 and the return pump 19 and operations of the supply source valve 16 and the bypass valve 20 are controlled by a control device 21 (see FIG. 9).

The suction portion 15 b of the feed pump 15 is connected to the transfer liquid tank 23 and the cleaning liquid tank 24 through the suction passage 22. The transfer liquid tank 23 is for storing varnish, and the cleaning liquid tank 24 is for storing cleaning liquid.
The suction passage 22 is connected in the middle of the varnish suction passage 25 whose upstream end opens into the liquid in the transfer liquid tank 23, the cleaning liquid suction passage 26 whose upstream end opens into the liquid in the cleaning liquid tank 24, and the varnish suction passage 25. The air suction passage 27 is formed. In this embodiment, the varnish suction passage 25 corresponds to the “transfer liquid suction passage” in the present invention.

In the middle of the varnish suction passage 25, a first flow path switching valve 28 for opening and closing the passage is provided.
The air suction passage 27 opens at the tip into the atmosphere and is connected to the downstream side of the first flow path switching valve 28 in the varnish suction passage 25. In the middle of the air suction passage 27, a second flow path switching valve 29 for opening and closing the passage is provided.
In the middle of the cleaning liquid suction passage 26, a third flow path switching valve 30 for opening and closing the passage is provided. Operations of the first to third flow path switching valves 28 to 30 are controlled by the control device 21. The first to third flow path switching valves 28 to 30 are controlled by the control device 21 so that the feed pump 15 discharges any one of varnish and other fluids (air and cleaning liquid) to the feed passage 12. Can be opened and closed.

  The return passage 14 connected to the upper end of the chamber 6 has an upper portion 14a that opens downward on the liquid receiving tank 13, and a lower portion 14b that communicates the inside of the liquid receiving tank 13 with the suction portion 19a of the return pump 19. And is composed of. The upper part 14 a is connected to the transfer liquid outlet 6 b of the chamber 6. Varnish and cleaning liquid discharged from the transfer liquid outlet 6 b of the chamber 6 to the upper part 14 a of the return passage 14 flow down to the liquid receiving tank 13. The return pump 19 is constituted by a diaphragm pump.

  The discharge portion 19 b of the return pump 19 is connected to a plurality of tanks via a recovery passage 31. The plurality of tanks are a transfer liquid tank 23, a cleaning liquid tank 24, and a waste liquid tank 32. The waste liquid tank 32 stores a waste liquid in which a varnish and a cleaning liquid are mixed. In this embodiment, the transfer liquid tank 23, the cleaning liquid tank 24, and the waste liquid tank 32 correspond to the “return tank” in the present invention.

The recovery passage 31 includes a transfer liquid recovery passage 33 whose downstream end is connected to the transfer liquid tank 23, a cleaning liquid recovery passage 34 whose downstream end is connected to the cleaning liquid tank 24, and waste liquid whose downstream end is connected to the waste liquid tank 32. And a recovery passageway 35. The transfer liquid recovery passage 33 is provided with a fourth flow path switching valve 36 for opening and closing the passage.
The cleaning liquid recovery passage 34 is provided with a fifth flow path switching valve 37 for opening and closing the passage. The waste liquid recovery passage 35 is provided with a sixth flow path switching valve 38 for opening and closing the passage. Operations of the fourth to sixth flow path switching valves 36 to 38 are controlled by the control device 21.

  As shown in FIG. 9, the control device 21 is connected to an operation switch 41 and operates the varnish supply device 11 in accordance with the operation content of the operation switch 41. When the operation switch 41 performs an operation of transferring the varnish to the sheet 2, the control device 21 causes the varnish supply device 11 to perform a transfer operation. In this case, the control device 21 opens the supply source valve 16, the first flow path switching valve 28, and the fourth flow path switching valve 36, and closes the other valves to the feed pump 15 and the return pump. 19 is operated.

When the varnish supply device 11 performs the transfer operation in this way, the varnish in the transfer liquid tank 23 is sucked into the feed pump 15 through the varnish suction passage 25 and is supplied from the feed pump 15 into the chamber 6 through the feed passage 12. . The varnish supplied into the chamber 6 is transferred from the anilox roller 5 to the transfer cylinder 4 and transferred from the transfer cylinder 4 to the sheet 2.
Excess varnish in the chamber 6 is discharged from the upper portion 14 a of the return passage 14 to the liquid receiving tank 13, and is sucked into the return pump 19 from the liquid receiving tank 13 through the lower portion 14 b of the return passage 14. The varnish returns to the transfer liquid tank 23 through the transfer liquid recovery passage 33.

  When changing the type of varnish or when performing maintenance of the chamber 6, the inside of the chamber 6 is cleaned by a predetermined cleaning method. This cleaning method is performed by the control device 21 operating each valve, the feed pump 15 and the return pump 19 as shown in FIG. In FIG. 2, “O” means that the valve is open, and “X” means that the valve is closed. Although the details of the cleaning method according to this embodiment will be described later, the cleaning method includes a plurality of steps S1 to S4 as shown in FIG.

  In carrying out this cleaning method, the control device 21 first executes a varnish collection step S1. The varnish recovery step S1 includes a first varnish recovery step S1A and a second varnish recovery step S1B.

  First, in the first varnish recovery step S1A, the control device 21 opens the supply source valve 16, the bypass valve 20, the second flow path switching valve 29, and the fourth flow path switching valve 36, and the other While closing the valve, the feed pump 15 and the return pump 19 are operated. When the first varnish collecting step S1A is executed, air is sucked into the varnish suction passage 25 and supplied to the chamber 6 through the feed passage 12 as shown by the filled passage in FIG. The The varnish discharged from the chamber 6 is returned to the transfer liquid tank 23 through the return path 14 and the transfer liquid recovery path 33.

  Then, the control apparatus 21 performs 2nd varnish collection | recovery step S1B, and stops only the feed pump 15. FIG. When the second varnish collecting step S1B is executed, the varnish in the chamber 6 flows backward through the feed passage 12 and returns from the feed passage 12 through the bypass passage 18 as shown in FIG. 14 is sucked into. The control device 21 stops the return pump 19 after maintaining the varnish supply device 11 in the same state for a predetermined time. When the return pump 19 is stopped, the second varnish collecting step S1B is completed.

  Next, the control device 21 executes a cleaning liquid supply step S2. In the cleaning liquid supply step S2, the supply source valve 16, the third flow path switching valve 30, and the sixth flow path switching valve 38 are opened, the other valves are closed, the feed pump 15 and the return pump 19, Works. When the cleaning liquid supply step S2 is executed, the cleaning liquid is sent to the chamber 6 by the feed pump 15 and the waste liquid consisting of the mixture of the varnish and the cleaning liquid discharged from the chamber 6 is discharged as shown in FIG. It is collected in the waste liquid tank 32 through the return passage 14 and the waste liquid collection passage 35. The control device 21 stops the feed pump 15 and the return pump 19 after maintaining the varnish supply device 11 in the same state for a predetermined time. When these pumps are stopped, the cleaning liquid supply step S2 is completed.

  Thereafter, the control device 21 executes a cleaning liquid circulation step S3. In the cleaning liquid circulation step S3, the supply source valve 16, the third flow path switching valve 30, and the fifth flow path switching valve 37 are opened, the other valves are closed, the feed pump 15 and the return pump 19, Works. When the cleaning liquid circulation step S3 is executed, the cleaning liquid is sent to the chamber 6 by the feed pump 15 and the cleaning liquid discharged from the chamber 6 is returned to the return path 14 and the cleaning liquid recovery path 34, as shown in FIG. And is collected in the cleaning liquid tank 24. The control device 21 stops the feed pump 15 and the return pump 19 after maintaining the varnish supply device 11 in the same state for a predetermined time. When these pumps are stopped, the cleaning liquid circulation step S3 is completed.

  After circulating the cleaning liquid in this way, the control device 21 executes a cleaning liquid recovery step S4. The cleaning liquid recovery step S4 includes a first cleaning liquid recovery step S4A and a second cleaning liquid recovery step S4B. First, in the first cleaning liquid recovery step S4A, the control device 21 opens the supply source valve 16, the bypass valve 20, the second flow path switching valve 29, and the fifth flow path switching valve 37. While closing the valve, the feed pump 15 and the return pump 19 are operated.

  When the first cleaning liquid recovery step S4A is executed, air is sucked into the varnish suction passage 25 and supplied to the chamber 6 through the feed passage 12, as shown in the passage in FIG. The The cleaning liquid discharged from the chamber 6 is returned to the cleaning liquid tank 24 through the return passage 14 and the cleaning liquid recovery passage 34.

Thereafter, the control device 21 executes the second cleaning liquid recovery step S4B and stops only the feed pump 15. When the second cleaning liquid recovery step S4B is executed, the cleaning liquid in the chamber 6 flows backward through the feed passage 12 and returns from the feed passage 12 through the bypass passage 18 as shown in FIG. 14 is sucked into. After maintaining the varnish supply device 11 in the same state for a predetermined time, the control device 21 stops the return pump 19 and closes all the valves. Thus, the return pump 19 is stopped and all the valves are closed, whereby the second cleaning liquid recovery step S4B is completed.
Thereafter, the control device 21 executes again the cleaning liquid supply step S2, the cleaning liquid circulation step S3, and the cleaning liquid recovery step S4 described above, and finishes the cleaning operation of the varnish supply device 11.

In the liquid transfer apparatus 1 configured as described above, the return pump is in a state where the bypass valve 20 is open and the feed pump 15 is stopped in the second varnish recovery step S1B and the second cleaning liquid recovery step S4B described above. As 19 operates, the varnish and the cleaning liquid flow backward through the feed passage 12 for supplying the varnish to the chamber 6 and are discharged via the bypass passage 18. For this reason, the varnish and the cleaning liquid are discharged not only from the transfer liquid outlet 6 b of the chamber 6 but also from the transfer liquid inlet 6 a.
Therefore, according to this embodiment, it is possible to provide a liquid transfer apparatus that can efficiently remove the remaining liquid in the chamber 6 and that does not drip when the chamber 6 is detached from the anilox roller 5. it can.

The feed passage 12 according to this embodiment is connected to the lower end portion of the chamber 6, and the return passage 14 is connected to the upper end portion of the chamber 6. For this reason, according to this embodiment, since the varnish can be discharged from the lower end portion of the chamber 6, the varnish does not remain in the chamber 6.
Therefore, when the cleaning liquid is supplied into the chamber 6 for cleaning after the varnish is discharged, the waste liquid composed of the mixture of the varnish and the cleaning liquid becomes small. As a result, it is possible to provide a liquid transfer apparatus that consumes less cleaning liquid and can reduce the cost for cleaning.

  In this embodiment, a transfer liquid tank 23 in which a transfer liquid supplied to the chamber 6 is stored is provided. The suction portion 15 b of the feed pump 15 is connected to the transfer liquid tank 23 via the suction passage 22. The suction passage 22 includes a varnish suction passage 25 having a tip opened in the liquid in the transfer liquid tank 23 and provided with a first flow path switching valve 28 in the middle, and a varnish suction passage 25 in the middle of the first passage switching valve 28. The air suction passage 27 is connected to the downstream side of the flow path switching valve 28, the tip is released into the atmosphere, and the second flow path switching valve 29 is provided in the middle.

For this reason, air can be sent from the air suction passage 27 to the varnish suction passage 25, and the contents in the entire passage from the varnish suction passage 25 through the chamber 6 to the return pump 19 can be replaced with air. Here, the contents refer to gases and liquids that may be present in the passage, such as varnish, cleaning liquid, and air, and may be a residue obtained by mixing them.
Therefore, according to this embodiment, since the varnish can be forcibly recovered, it is possible to provide a liquid transfer apparatus that completes the operation of discharging the varnish in the chamber 6 in a short time.

In this embodiment, a cleaning liquid tank 24 in which a cleaning liquid is stored is provided. Further, in the middle of the varnish suction passage 25 and on the downstream side of the first flow path switching valve 28, the tip opens into the liquid in the cleaning liquid tank 24, and a third flow path switching valve 30 is provided in the middle. The cleaning liquid suction passage 26 is connected.
For this reason, the cleaning liquid can be sent to the chamber 6 using the feed pump 15 for sending the varnish to the chamber 6. The bypass passage 18 can also be used when the cleaning liquid is discharged from the chamber 6. That is, the cleaning liquid flows backward through the feed passage 12 and is sucked into the return pump 19 via the bypass passage 18.
Therefore, according to this embodiment, even if the inside of the chamber 6 is cleaned with the cleaning liquid after the varnish is discharged, the liquid transfer apparatus in which the residual liquid does not drip when the chamber 6 is detached from the anilox roller 5. Can be provided.

The method for cleaning a chamber for a liquid transfer apparatus according to this embodiment includes a first varnish recovery step S1A and a second varnish recovery step S1B. In the first varnish recovery step S1A, air is sent to the chamber 6 by the feed pump 15 with the bypass valve 20 that opens and closes the bypass passage 18 open, and the varnish discharged from the chamber 6 is returned by the return pump 19 It is sent to the transfer liquid tank 23. In the second varnish collecting step S1B, the feed pump 15 is stopped while the bypass valve 20 is open, and the varnish discharged from the chamber 6 via the bypass passage 18 is returned to the transfer liquid tank 23 by the return pump 19. Sent to.
For this reason, according to this cleaning method, since the varnish in the chamber 6 is forcibly discharged by air and then discharged from the transfer liquid inlet 6a of the chamber 6, the varnish is efficiently discharged. Therefore, according to this embodiment, it is possible to provide a method for cleaning a chamber for a liquid transfer apparatus in which the step of collecting varnish is completed quickly.

  In the embodiment described above, an example of the liquid transfer apparatus 1 that transfers varnish to the sheet 2 in the printing machine has been described. However, the present invention can also be applied to a liquid transfer apparatus that transfers ink to a sheet.

  In the embodiment described above, it is written that the return passage 14 is constituted by the liquid receiving tank 13, the upper part 14a, and the lower part 14b. However, the present invention is not limited to this, and there is no liquid receiving tank 13, and the upper part 14a The return passage 14 may be connected (directly connected) to the lower portion 14b.

  In the above-described embodiment, the type of varnish is not mentioned, but when an aqueous varnish is used, water is used in addition to a commonly used cleaning liquid, and water is also sent to the chamber by a feed pump. .

  DESCRIPTION OF SYMBOLS 1 ... Liquid transfer apparatus, 2 ... Sheet, 5 ... Anilox roller, 6 ... Chamber, 12 ... Feed passage, 14 ... Return passage, 15 ... Feed pump, 18 ... Bypass passage, 19 ... Return pump, 20 ... Bypass valve, 22 DESCRIPTION OF SYMBOLS Suction passage, 23 ... Transfer liquid tank, 24 ... Cleaning liquid tank, 25 ... Varnish suction passage, 26 ... Cleaning liquid suction passage, 27 ... Air suction passage, 28 ... First flow path switching valve, 29 ... Second flow path Switching valve, 30... Third flow path switching valve, 32.

Claims (5)

An anilox roller for supplying a sheet of transfer liquid consisting of either varnish or ink;
A chamber for storing a transfer liquid in cooperation with the anilox roller;
A feed pump connected to the chamber via a feed passage and discharging any one of a transfer liquid and other fluids to the feed passage;
A return pump for sending the contents of the chamber to a return tank via a return passage;
A bypass passage connecting a portion of the feed passage downstream from the feed pump and a portion of the return passage upstream of the return pump; and
A liquid transfer apparatus comprising a bypass valve for opening and closing the bypass passage. The liquid transfer apparatus according to claim 1.
The feed passage is connected to a lower portion of the chamber;
The liquid transfer apparatus, wherein the return passage is connected to an upper portion of the chamber. The liquid transfer device according to claim 1 or 2,
It further includes a transfer liquid tank in which the transfer liquid is stored,
The suction portion of the feed pump is connected to the transfer liquid tank via a suction passage,
The suction passage includes a transfer liquid suction passage having a tip opened in the liquid of the transfer liquid tank and provided with a first flow path switching valve in the middle.
An air suction passage that is connected to the downstream side of the first flow path switching valve and is connected to the downstream side of the first flow path switching valve, the tip is released into the atmosphere, and the second flow path switching valve is provided midway. A liquid transfer apparatus comprising: The liquid transfer apparatus according to claim 3.
It further includes a cleaning liquid tank in which cleaning liquid is stored,
In the middle of the transfer liquid suction passage and downstream of the first flow path switching valve, a cleaning liquid suction path having a tip opened into the liquid of the cleaning liquid tank and having a third flow path switching valve in the middle. A liquid transfer device, wherein the liquid transfer device is connected. A method for cleaning a chamber for a liquid transfer apparatus, wherein the chamber is cleaned using the bypass passage according to claim 1,
A method of cleaning a chamber for a liquid transfer apparatus, wherein the feed pump is stopped and the return pump is operated while the bypass valve is open.

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