REFRIGERATION UNIT FOR A PRINTING MACHINE AND PRINTING MACHINE

Abstract

A refrigeration unit (26) for a printing machine is presented. It comprises a dryer interface (28) connectable to a dryer unit (18) of the printing machine in a heat conductive manner and a print interface (30) connectable to a printing unit (14) of the printing machine in a heat conductive manner, wherein the refrigeration unit (26) is adapted to transfer heat (32, 34) from the print interface (30) to the dryer interface (28). Furthermore, a printing machine is described. It comprises a printing unit (14) adapted for printing on a web of carrier material, a dryer unit (18) being adapted for drying printed web of carrier material, and a refrigeration unit (26) as mentioned above.

Claims

1. A refrigeration unit for a printing machine, especially for a flexographic printing machine, the refrigeration unit comprising: a dryer interface connectable to a dryer unit of the printing machine in a heat conductive manner, and a print interface of the printing machine in a heat conductive manner, wherein the refrigeration unit is adapted to transfer heat from the print interface to the dryer interface.

2. The refrigeration unit according to claim 1, wherein the refrigeration unit further comprises a coolant circuit having a first coolant circuit portion being attributed to the print interface and being positionable in the printing unit or adjacent to the printing unit, wherein the first coolant circuit portion is adapted for absorbing heat originating from the printing unit, and having a second coolant circuit portion being attributed to the dryer interface and being positionable in the dryer unit or adjacent to the dryer unit, wherein the second coolant circuit portion is adapted for delivering heat to the dryer unit.

3. The refrigeration unit according to claim 2, wherein the first coolant circuit portion comprises an evaporator adapted to evaporate coolant, and the second coolant circuit portion comprises a condenser adapted to condense coolant, wherein the coolant circuit further comprises a compressor being positioned between the first coolant circuit portion and the second coolant circuit portion, when regarded in the sense of coolant flow, and wherein the coolant circuit further comprises an expansion valve being positioned between the second coolant circuit portion and the first coolant circuit portion when regarded in the sense of coolant flow.

4. The refrigeration unit according to claim 2, wherein the refrigeration unit comprises at least one ventilation unit positioned adjacent to the second coolant circuit portion, wherein the ventilation unit is adapted to create an air flow in the area of the second coolant circuit portion.

5. A printing machine, especially a flexographic printing machine, comprising: a printing unit adapted for printing on a web of carrier material, a dryer unit being adapted for drying printed web of carrier material, and the refrigeration unit according to claim 1, wherein the refrigeration unit is heat conductively connected to the dryer unit via the dryer interface, and wherein the refrigeration unit is heat conductively connected to the printing unit via the print interface.

6. The printing machine according to claim 5, wherein the refrigeration unit further comprises a coolant circuit having a first coolant circuit portion, and wherein the first coolant circuit portion is at least partially located inside a printing drum or adjacent to the printing drum.

7. The printing machine according to claim 5, wherein the dryer unit comprises a main dryer adapted for drying printed web of carrier material after the application of one or more inks of different colors.

8. The printing machine according to claim 5, wherein the dryer unit comprises an intracolor dryer adapted for drying printed web of carrier material between the application of inks of different colors.

9. The printing machine according to claim 5, wherein the dryer unit comprises a central ventilation system wherein the heat from the printing unit is transferred to the central ventilation system.

10. The printing machine according to claim 5, wherein the refrigeration unit is connected to the dryer unit via an air conduit.

Description

[0023] The invention will now be explained with reference to an embodiment which is shown in the attached drawings. In the drawings,

[0024] FIG. 1 shows a flexographic printing machine according to the invention comprising a refrigeration unit according to the invention,

[0025] FIG. 2 shows a partial schematic sectional view of the flexographic printing machine of FIG. 1,

[0026] FIG. 3 shows a view of the flexographic printing machine of FIG. 1 along direction III,

[0027] FIG. 4 shows a partial sectional view IV-IV of the flexographic printing machine of FIG. 3, and

[0028] FIG. 5 schematically shows the functional principle of the refrigeration unit according to the invention.

[0029] FIG. 1 shows a printing machine 10, which is a flexographic printing machine in the examples shown.

[0030] It comprises a web feeding unit 12, where a web of carrier material may be stored before the printing process takes place, a printing unit 14 adapted for printing on the web of carrier material, and a storage unit 16, where printed web is stored after the printing process.

[0031] The printing machine 10 also has a dryer unit 18, which comprises a main dryer 18a adapted for drying printed web of carrier material after the printing process.

[0032] Details of the printing unit 14 may be seen in FIG. 2.

[0033] As a central element the printing unit 14 comprises a central impression drum 20, which is coupled to eight ink application units 22a, 22b, 22c, 22d, 22e, 22f, 22g, 22h, each of which is adapted to apply an ink of a different color to the web 24.

[0034] Consequently, the flexographic printing machine 10 may be termed an eight color printing machine.

[0035] Between each of the ink application units 22a and 22b, 22b and 22c, 22c and 22d, 22d and 22e, 22e and 22f, 22f and 22g and 22g and 22h a so-called intracolor dryer 18b is provided, which is part of the dryer unit 18. These intracolor dryers 18b are adapted for drying printed web of carrier material between the application of inks of different colors.

[0036] In other words, the ink applied to the web 24 by the ink application unit 22a is dried by an intracolor dryer 18b before ink of a different color is applied to the web 24 by the ink application unit 22b and so on.

[0037] The flexographic printing machine 10 also comprises a refrigeration unit 26 which is heat conductively connected to the dryer unit 18 via a dryer interface 28, and which is heat conductively connected to the printing unit 14 via a print interface 30 (cf. FIG. 5).

[0038] The refrigeration unit 26 is adapted to transfer heat from the print interface 30 to the dryer interface 28. In other words, the refrigeration unit 26 is adapted to extract heat from the printing unit 14, i.e. it is adapted to cool the printing unit 14, and supply the heat to the dryer unit 18, where it is used as process heat.

[0039] In FIG. 5 the heat being extracted from the printing unit 14 is illustrated by arrow 32 and the heat being supplied to the dryer unit 18 is illustrated by arrow 34.

[0040] In order to do so, the refrigeration unit 26 comprises a coolant circuit 36, wherein a flow direction of coolant is indicated by arrow 38.

[0041] The coolant circuit 36 has a first coolant circuit portion 36a which is attributed to the print interface 30 and comprises an evaporator 40 adapted to evaporate the coolant.

[0042] The first coolant circuit portion 36a is positioned adjacent to the printing unit 14. Alternatively, the first coolant circuit portion 36a is at least partially located inside the printing drum 20 or adjacent to the printing drum 20.

[0043] Consequently, the first coolant circuit portion 36a is adapted for absorbing heat 32 originating from the printing unit 14 and uses this heat 32 for evaporating the coolant.

[0044] The coolant circuit 36 also has a second coolant circuit portion 36b which is attributed to the dryer interface 28 and comprises a condenser 42 adapted to condense coolant.

[0045] The second coolant circuit portion 36b is positioned adjacent to the dryer unit 18.

[0046] Consequently, the second coolant circuit portion 36b is adapted for delivering heat 34 to the dryer unit 18 by condensing coolant.

[0047] The coolant circuit is completed by a compressor 44 being positioned between the first coolant circuit portion 36a and the second coolant circuit portion 36b, when regarded in the sense of coolant flow 38. In the example shown the compressor 44 is interposed between the evaporator 40 and the condenser 42.

[0048] Moreover, the coolant circuit 36 comprises an expansion valve 46 being positioned between the second coolant circuit portion 36b and the first coolant circuit portion 36a, when regarded in the sense of coolant flow 38.

[0049] Additionally, the refrigeration unit 26 comprises a ventilation unit 48 positioned adjacent to the second coolant circuit portion 36b. The ventilation unit 48 is adapted to create an air flow in the area of the second coolant circuit portion 36b, which enhances heat transfer from the coolant to the dryer unit 18.

[0050] The air flow created by the ventilation unit 48 may be directly fed to the dryer unit 18.

[0051] In this context, the dryer unit 18 may also comprise a central ventilation system 18c, wherein the heat 34 originating from the printing unit 14 is transferred to the central ventilation system 18c.

[0052] The ventilation system 18c may supply the intracolor dryers 18b with heated air via conduits 18d and the main dryer 18a via conduits 18e.

[0053] The coolant circuit 36 may use a hydrocarbon coolant, e.g. propane or butane.

[0054] The refrigeration unit 26 operates as follows.

[0055] Coolant is evaporated in the evaporator 40 by heat 32 originating from the printing unit 14.

[0056] Subsequently, gasified coolant is fed to the condenser 42 via the compressor 44, where it is condensed, i.e. the coolant is liquefied. The heat 34 resulting from the condensation process is fed to the dryer unit, especially to a central ventilation system 18c thereof. This process is assisted by the ventilation unit 48.

[0057] After that, the coolant flows back to the evaporator 40 via the expansion valve 46.

[0058] In the example shown approximately 15 kW of heat are transferred from the printing unit 14 to the dryer unit 18.