Cleaning station for needle nozzles

Abstract

A cleaning apparatus for cleaning a nozzle of a liquid dispensing device is disclosed. The cleaning apparatus includes a base member supporting a receiving head including a receiving opening for receiving a portion of the nozzle to be cleaned, a gas inlet for receiving pressurized gas, and an outlet at the receiving head for applying pressurized gas to the nozzle for flushing the nozzle. The receiving opening can include a sealing edge for sealing the receiving head against the nozzle when the nozzle is received in the receiving opening. The cleaning apparatus can also include at least one of a discharge tube, a collection vessel and a filter element.

Claims

1. A cleaning apparatus for cleaning a nozzle of a liquid dispensing device, the cleaning apparatus comprising: a base member supporting a receiving head comprising a receiving opening for receiving a portion of the nozzle to be cleaned; a gas inlet for receiving pressurized gas; and a gas channel having a gas outlet at the receiving head for applying pressurized gas to the nozzle for flushing the nozzle, wherein the receiving opening comprises a sealing edge for sealing the receiving head against the nozzle when the nozzle is received in the receiving opening, and wherein the gas outlet is adjacent the sealing edge, and wherein the gas channel is formed as a continuous circumferential slot around the receiving opening.

2. The cleaning apparatus of claim 1, wherein the receiving head is movable from a first position to a second position upon contact with the nozzle, and wherein upon movement of the receiving head from the first position into the second position, the gas inlet and the gas outlet are in gas communication for supplying gas from the gas inlet to the gas outlet.

3. The cleaning apparatus of claim 2, wherein the receiving head is moveable against a biasing force.

4. The cleaning apparatus of claim 3, further comprising biasing means for biasing the receiving head into the first position.

5. The cleaning apparatus of claim 4, wherein the biasing means comprise at least one coiled spring and/or at least one gas pressure cavity forming a pneumatic spring.

6. The cleaning apparatus of claim 2, further comprising a shut-off valve between the gas inlet and the gas outlet.

7. The cleaning apparatus of claim 6, wherein the shut-off valve is formed by a portion of the receiving head which blocks a gas conduit in the first position and unblocks the gas conduit in the second position.

8. The cleaning apparatus of claim 1, wherein the gas channel is formed such that the pressurized gas is applied in a substantially radial direction to the nozzle.

9. The cleaning apparatus of claim 1, wherein the gas channel is formed as a laval nozzle.

10. The cleaning apparatus of claim 1, wherein the gas channel has at least one tapered surface such that the gas channel flares open to the direction of the receiving opening.

11. The cleaning apparatus of claim 1, wherein the gas channel has a width of 1 mm or less.

12. The cleaning apparatus of claim 1, wherein the receiving head comprises a discharge channel for discharging cleaned off residual fluid.

13. The cleaning apparatus of claim 12, wherein a gas conduit leads to a substantially cylindrical space formed outside of the discharge channel and leading to the gas channel.

14. The cleaning apparatus of claim 13, wherein the cylindrical space is formed between first and second body parts of the receiving head which are fixed together.

15. The cleaning apparatus of claim 1, further comprising a removable nut defining the receiving opening with the sealing edge.

16. The cleaning apparatus of claim 12, wherein the discharge channel is provided with a discharge tube for lining an inner wall of the discharge channel.

17. The cleaning apparatus of claim 1, further comprising a collection vessel for collecting residual liquid cleaned from the nozzle.

18. The cleaning apparatus of claim 1, further comprising a second gas outlet for discharging gas which has been used to flush the nozzle, wherein the second gas outlet is provided with a filter element for filtering the used gas exiting the cleaning apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the accompanying drawings

(2) FIG. 1 shows a cross-sectional view of the cleaning apparatus;

(3) FIG. 2 shows a detail of FIG. 1;

(4) FIG. 3 shows a top view of the cleaning apparatus of FIG. 1;

(5) FIG. 4 shows the cleaning apparatus of FIG. 1 in another cross-sectional view, wherein the receiving head is in the first position; and

(6) FIG. 5 shows the cleaning apparatus of FIG. 4, wherein the receiving head is in the second position.

DETAILED DESCRIPTION

(7) A cleaning apparatus 1 (cf. FIG. 1) comprises a base member 2 and a receiving head 4. The receiving head 4 is supported in the base member 2 and comprises a receiving opening 6 for receiving a portion of a nozzle 102 to be cleaned (only shown in FIG. 5). The opening 6 is limited by a sealing edge 7.

(8) The base member 2 comprises a lower portion 8 having a foot portion 10 by means of which the apparatus 1 may be located on a table, or a fixed to any other supporting structure. The lower portion 8 is substantially cup-shaped and defines a cavity 12 inside a circumferential wall 14. The wall 14 has a tubular shape and comprises screw threaded bores 16 (only one shown in FIG. 1; cf. also FIG. 3). The top surface of the wall 14 receives a head portion 18 of the base member 2. The head portion 18 is fixed to the base portion 8 by means of screws 20, which comprise an enlarged and knurled screw head 22, which can be gripped and screwed manually by an operator.

(9) The head portion 18 comprises a central opening 24 around central axis A, in which the receiving head 4 is movably positioned. The base member 2 furthermore comprises an abutment collar 26 screwed against the head portion 18 by means of screws 28, for supporting the receiving head 4. The abutment collar 26 comprises recesses 30 (only one shown in FIG. 1), in which respective coiled springs 32 are placed, acting as biasing means for biasing the receiving head 4 into a first position P1 in which the receiving head 4 is in an upper position with respect to the base member 2 (cf. FIG. 4).

(10) The coiled springs 32 act against a flange portion 34 of a first body part 36 of the receiving head 4. The first body part 36 comprises the flange portion 34 and an axial extension 38 seated in a through opening 40 of the support collar 26. An O-ring 42 is arranged between the axial extension 38 and inner circumferential surface of the through hole 40 for sealing the receiving member 4 against the base member 2. The first body part 36 comprises a tube portion 44 extending coaxially with axis A from the opposing side of the extension 36 toward the receiving opening 6 (see also FIG. 2).

(11) The receiving head 4 furthermore comprises a second body part 46 which is screwed by means of at least one screw 48 against at the first body part 36. The second body part 46 comprises an axial extension 50 protruding through the opening 24 and sealed by means of an O-ring 52 against the opening 24. The extension 50 extends coaxially with the tube portion 44 and around the tube portion 44 and defines a cylindrical space 54 between the tube portion 44 and the extension 50. At an upper portion 56, the extension 50 comprises a screw threaded portion 58 receiving a nut 60 thereon which covers the cylindrical space 54 and defines the receiving opening 6 with the sealing edge 7.

(12) The cleaning apparatus 1 comprises a shut-off valve 70. The shut-off valve 70 comprises according to this embodiment at least one radial extending conduit 72 and blocking portion 74. The conduit 72 is formed in the receiving head, in particular the second body part 46 of the receiving head 4 and connecting the cylindrical space 54 with the outside of the receiving head 4. The conduit 72 is blockable by means of a blocking portion 74 of the base member 2, in particular the head portion 58 (cf. FIG. 2). It shall be noted that a plurality of conduits 72 is provided circumferentially around the second body part 46, so that a cross section of the opened shut-off valve 70 is large enough to provide a sufficient gas flow. In FIGS. 1 and 2, the receiving head 4 is shown in intermediate position and the blocking portion 74 only extends in an upper half of conduit 72, with respect to FIG. 2. When the receiving head 4 is in the first position P1 (see FIG. 4) the conduit 72 is fully closed by means of the portion 74 and in a second position P2 in which the receiving head 4 is in a lower position and moved against the biasing force of the coiled springs 32 with respect to the base member 2 (see FIG. 5). In this second position P2, the conduit 72 is fully open. This will be described with respect to FIGS. 4 and 5 below.

(13) An end portion 76 of the tube portion 44 and a lip portion 78 of the nut 60 together define a gas channel 80 for cleaning gas or purge gas for cleaning the nozzle 102 (FIG. 5). The channel 80 has an outlet 81 through which the gas can be dispensed towards the nozzle 102, when the nozzle 102 is received in the receiving opening 6. In this embodiment, the gas channel 80 has the shape of a ring (annulus) terminating in the circumferential outlet 81. In operation gas is being guided or projected radially and flows through gas channel 81 from the outside to the central axis A and thus to a nozzle 102 (see FIG. 5), which is received in the receiving opening 6. The lip portion 78 terminates in the sealing edge 7. While the lower surface of the lip 78 is substantially flat, the upper surface 82 of the portion 76 is tapered and thus the gas channel 80 flares open toward axis A. The gas channel 80 is thus formed according to a laval nozzle for providing a supersonic gas stream. At the neck portion the gas channel 80 has a cross sectional width of 0.3 mm.

(14) The gas channel 80 and thus the outlet 81 is in gas communication with the cylindrical space 54, which is in gas communication with conduit 72. Therefore, when gas enters conduit 72 and subsequently enters the cylindrical space 54 and exits the receiving head 4 through the outlet 81, pressurized gas is applied to the nozzle 102 for flushing the nozzle 102.

(15) The receiving opening 6 opens downward with respect to FIGS. 1 and 2 in a discharge channel 84. The discharge channel 84 runs from the receiving opening 6 to the cavity 12. The discharge channel 84 is defined circumferentially by the first body part 36 of the receiving head. According to this embodiment, the discharge channel 84 is lined by means of a discharge tube 86 which is received in the receiving head 4. The discharge tube 86 is formed as a disposable item and made out of a plastic material. The discharge tube 86 terminates within a collection vessel 88 which is cup-shaped and placed inside the cavity 12. Therefore, when a nozzle is received in the receiving opening 6 and flushed by means of gas exiting the gas channel 80, residual liquid is discharged through the discharge tube 86 and received in the collection vessel 88.

(16) When the nozzle 102 is received in the opening 6 and the receiving head 4 is pushed downwards, the nozzle 102 contacts the sealing edge 7 and is pressed against it so as to seal the nozzle tip 106 against the environment (cf. FIG. 5). Thus, the cleaned off particles remain inside the apparatus 1, in particular in the discharge tube 86 and the vessel 88.

(17) The cleaning apparatus furthermore comprises gas outlets 90 (one shown in FIG. 1; see FIG. 3) through which purge gas, which has travelled through the discharge channel 84 can exit the cleaning apparatus 1. The gas exits 90 are provided as bores in the head portion 18 and connecting the environment with the cavity 12. The openings 90 are provided with a filter element 92 which is seated on a rim 94 of the collection vessel and contacting the base member 2 at the head portion 18 and the support 26. The filter element 92 comprises a central through hole 96 through which the discharge tube 86 extends. The filter element 92 is formed as a disposable item. The openings 90 are evenly distributed about the base member 2 (cf. FIG. 3) so as to minimize a stream inside the vessel 88 and to use a maximum surface of the filter element 92. It is preferred that the openings 90 are additionally provided with sound absorbers.

(18) For maintenance, the disposable items 86, 88 and 92, namely the discharge tube 86, the vessel 88 and the filter element 92 can be changed. For this operation, an operator needs to loosen the screws 20, which are manually operable, and demounting the head portion 18 in which the receiving head 4 is seated, from the lower portion 8. Subsequently, the discharge tube 86 can be pulled out of the discharge channel 84, the filter element 92 and the vessel 88 can be taken off and replaced by a new filter element 92 and a new vessel 88. After a new discharge tube 86 has been placed in the discharge channel 84, the device can be closed again by fixing the screws 20.

(19) Now, with respect to FIGS. 4 and 5, the actuation of the gas flow will be described.

(20) The base member 2 comprises a gas inlet 96 in the head portion 18, provided with a connector 98 on which a hose of a high pressure net can be mounted. In FIG. 4, the receiving head 4 is shown in the first position P1, in which the receiving head 4 is in an upper position with respect to the base member 2 and the conduit 72 is fully closed by portion 74. Additionally, an O-ring 100 which is placed in a recess of the receiving head 4 is pushed against portion 74 for sealing the base member 2 against the receiving head 4. In this position, the coil springs 32 push the receiving head 4 into the first position P1 and no gas can flow from connector 98 to gas channel 80 and out of the outlet 81.

(21) When subsequently a nozzle 102, which is fixed to a dispenser by means of a nut 103, is received in the receiving opening 6 and pushed downwards with respect to FIG. 5, the receiving head 4 is moved downwards into the second position P2, thus moving the conduit 70 with respect to portion 74. The O-ring 100 disengages portion 74 and a gap 104 is provided between O-ring and portion 74. At the same time, conduit 72 is unblocked from blocking portion 74 and gas can flow from connector 98 to gas inlet 96, through conduit 72 into the cylindrical space 54 and through gas channel 80 and out of the outlet 81 to flush the tip 106 of nozzle 102 and downwards through the discharge channel 84, through the cavity 12, through filter element 92 and out of gas outlets 90. Since the sealing edge 7 seals the discharge channel 84 against the nozzle 102, the gas discharged from gas channel 80 will only travel to nozzle 102 and downwards to the discharge channel 84 but not out of the receiving opening 6. In an embodiment the sealing edge 7 may be provided with an additional sealing element, such as a rubber ring or the like. Liquid residues at the nozzle tip 106 are being flushed by means of the gas exiting the gas channel 80 and discharged downward through discharge channel 84 into collection vessel 88. When the nozzle 102 is removed again, the coil springs 32 push the receiving head 4 again to the first position P1 (see FIG. 4) and the gas flow will be stopped again.