CONDUIT FOR A LIQUID DISPENSER, METHOD OF PRODUCING IT AND USE THEREOF

Abstract

A conduit for a liquid dispenser which includes a tube for carrying liquid and a heating device for heating at least a section of the tube. The heating device includes a part for fixing the heating device to the tube. The part is a part injection-moulded over the tube along at least a section of a length of the tube. A method of producing the conduit and a use thereof.

Claims

1. A conduit for a liquid dispenser, comprising: a tube for carrying liquid; and a heating device for heating at least a section of the tube, wherein the heating device includes a part for fixing the heating device to the tube, and wherein the part is a part injection-moulded over the tube along at least a section of a length of the tube.

2. The conduit according to claim 1, wherein the injection-moulded part is arranged around the tube.

3. The conduit according to claim 1, wherein the heating device is an electrical heating device.

4. The conduit according to any one of the preceding claim 1, wherein the heating device includes a resistive heating part.

5. The conduit according to claim 4, wherein the resistive heating part is comprised in the part injection-moulded onto the tube.

6. The conduit according to claim 4, wherein the resistive heating part includes a wound heating wire.

7. The conduit according to claim 6, further including a carrier, wherein the heating wire is wound around the carrier and the carrier is arranged between the tube and the injection-moulded part.

8. The conduit according to claim 1, wherein the injection-moulded part includes at least one feature arranged to co-operate with a feature of a separate component of the heating device to lock the separate component to the injection-moulded part.

9. The conduit according to claim 1, wherein the heating device further includes a component arranged in heat-conducting relation to at least one of the injection-moulded part and the tube.

10. The conduit according to claim 9, wherein the component arranged in heat-conducting relation to at least one of the injection-moulded part and the tube is clamped thereto by the separate component locked to the injection-moulded part.

11. A method of manufacturing the conduit according to claim 1 for a liquid dispenser preceding claims, including the steps of: providing the tube for carrying a liquid; and fixing the heating device for heating at least a section of the tube to the tube, wherein the step of fixing the heating device includes placing at least the tube in a mould and injection-moulding a part of the heating device over at least a section of a length of the tube.

12. A dispenser for dispensing liquids, including the conduit according to claim 1.

13. The dispenser according to claim 12, wherein the conduit forms a dispensing outlet.

14. The dispenser according to claim 12, further including a fitting connecting the conduit to one of a manifold and a further conduit.

15. Use of A method, comprising the step of: using the conduit according to claim 1 to counter retrograde contamination in a liquid dispenser.

16. The conduit according to claim 2, wherein the heating device is an electrical heating device, and wherein the heating device includes a resistive heating part.

17. The conduit according to claim 16, wherein the resistive heating part is comprised in the part injection-moulded onto the tube, and wherein the resistive heating part includes a wound heating wire.

18. The conduit according to claim 17, further including a carrier, wherein the heating wire is wound around the carrier and the carrier is arranged between the tube and the injection-moulded part, and wherein the injection-moulded part includes at least one feature arranged to co-operate with a feature of a separate component of the heating device to lock the separate component to the injection-moulded part.

19. The conduit according to claim 18, wherein the heating device further includes a component arranged in heat-conducting relation to at least one of the injection-moulded part and the tube, and wherein the component arranged in heat-conducting relation to at least one of the injection-moulded part and the tube is clamped thereto by the separate component locked to the injection-moulded part.

20. A method of manufacturing the conduit according to claim 19 for a liquid dispenser, including the steps of: providing the tube for carrying a liquid; and fixing the heating device for heating at least a section of the tube to the tube, wherein the step of fixing the heating device includes placing at least the tube in a mould and injection-moulding a part of the heating device over at least a section of a length of the tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The invention will be explained in further detail with reference to the accompanying drawings, in which:

[0071] FIG. 1 is a front view of a dispenser;

[0072] FIG. 2 is a schematic diagram showing selected components of the dispenser;

[0073] FIG. 3 is a perspective view of a conduit provided with a heating device and comprised in the dispenser;

[0074] FIG. 4 is a plan view of the conduit of FIG. 3;

[0075] FIG. 5 is a cross-sectional view of the conduit of FIGS. 3 and 4;

[0076] FIG. 6 is a further cross-sectional view of the conduit of FIGS. 3-5;

[0077] FIG. 7 is a cross-sectional view through the conduit and a cap of the heating device;

[0078] FIG. 8 is a schematic diagram showing pulses supplied to the heating device in use; and

[0079] FIG. 9 is a flow chart illustrating steps in a method of manufacturing the conduit.

DETAILED DESCRIPTION OF THE INVENTION

[0080] A dispenser 1 for dispensing beverages is shown in the form of a table-top device (FIG. 1). The illustrated dispenser is conceived for dispensing various forms of treated aqueous beverages, in particular treated drinking water. Such a dispenser is also referred to as a water bar. The illustrated dispenser 1 is configured for dispensing filtered water at ambient temperature, chilled water and chilled sparking water, e.g. with a selectable degree of CO.sub.2. In other embodiments, the dispenser 1 may further or alternatively be configured to dispense untreated mains water, boiling or hot water (at a temperature above 90° C.), for example. Other formats, such as a floor-mounted appliance, are possible.

[0081] The dispenser 1 includes a housing 2 and a user interface 3 for selecting the type of beverage to be dispensed. A recess 4 is provided for placing a vessel under an outlet 5 to collect the beverage. The vessel may be a drinking glass or a bottle, for example. Measures are provided for preventing retrograde contamination by germs via the outlet 5, as will be explained. This type of contamination occurs through contact with the outlet 5, whereby germs are transferred to the outlet 5 and spread into the interior of the outlet 5. Minimizing the risk of such contamination makes the dispenser 1 suitable for use in settings such as waiting rooms in doctors' surgeries.

[0082] The dispenser 1 includes (FIG. 2) an inlet fitting 6 for connecting the dispenser to a supply of drinking water, e.g. the water mains. It further includes a filter system 7. The filter system 7 may be a combination of a replaceable filter cartridge and a filter head, for example. The type of treatment carried out by the filter system may include mechanical filtration, including membrane filtration, softening or decarbonization (reduction of carbonate hardness) through treatment by ion exchange resin, other types of sorption, including treatment by activated carbon or heavy metal scavengers, and the like, as well as combinations thereof. The filter system 7 may also be arranged to treat the water by elution, e.g. to adapt its mineral content.

[0083] The filtered system 7 is connected to a manifold 8 provided with solenoid valves (not shown separately) via a pump 9. The manifold 8 is arranged to direct the water to a cooler 10 containing a carbonator (not shown separately), so that the water is either chilled or chilled and carbonated. A gas supply valve 11 controls the delivery of CO.sub.2 to the carbonator from a gas container 12, which may also be a replaceable cartridge.

[0084] The treated water returns to the manifold 8, with one or more valves provided therein controlling the delivery of treated water to an outlet conduit 13. The outlet conduit 13 is a separate part connected by means of a fitting 14 to an interconnecting conduit 15 extending from the manifold 8. The interconnecting conduit 15 may be a flexible tube, for example. Thus, the outlet conduit 13 can be relatively short, which makes it easier to manufacture. Also, the outlet conduit 13 can be made of a different material, in particular one that conducts heat better than the material of the interconnecting conduit 15.

[0085] The operation of the dispenser 1 is controlled by a controller 16, The controller 16 is provided with a measurement signal from a temperature sensor 17. The controller 16 also directs the operation of a power control device 18 that is arranged to supply electrical power to a heating device 19 of the outlet conduit 13. This heating device 19 is arranged to heat a section of the outlet conduit 13 to create a thermal barrier for preventing or at least countering retrograde contamination.

[0086] The outlet conduit 13 includes a tube 20 made of material that conducts heat relatively well, e.g. metal. It may be made of stainless steel, which is certified for contact with beverages. The tube 20 may have a wall thickness below 1 mm, e.g. between 0.5 and 1 mm. The tube 20 comprises an essentially straight, circle-cylindrical section 21 that transitions into an outlet section 22 via a curved, elbow-shaped section 23. The curved section 23 has an essentially constant radius of curvature. In use, the circle-cylindrical section 21 may be oriented essentially horizontally, with the outlet section 22 depending downwards. This reduces the overall height of the dispenser 1. The heating device 19 need not be located above the outlet section 22. The absence of unnecessary bends means that stagnation zones are avoided, further contributing to the prevention of contamination. With the outlet section 22 at a lower level than the section 21 at the opposite end of the tube 20 due to the curved section 23, the tube 20 is essentially emptied of water every time dispensing ends.

[0087] A groove 24 is provided on the exterior of the circle-cylindrical section 21, which allows for a shape-lock with the fitting 14. Alternatively-shaped features fulfilling the same function of co-operating with the fitting 14 to provide a shape-lock may be used in other embodiments.

[0088] Leads 25a,b provide an electrical connection between the power control device 18 and the heating device 19. The leads 25a,b are provided with an insulating cladding and arranged to withstand temperatures up to at least 200° C.

[0089] An end of a first lead 25a is crimped to a wire section extending from a thermal fuse 26 (FIG. 7). An end of a second lead 25b is crimped to a heating wire 27 arranged in a coil on a carrier 28. The heating wire 27 is coated with an electrically insulating coating, for example made of polytetrafluoroethylene, so that adjacent turns of the heating wire 27 can touch each other.

[0090] The carrier 28 is generally spool-shaped (FIGS. 5,6). It is provided with flanges 29,30 to locate the coiled heating wire 27. Thus, the heating wire 27 can be coiled relatively easily onto the carrier 28. The carrier 28 may be made of electrically insulating material, for example.

[0091] The carrier 28 is fixed to the tube 20 by a mass 31 of injection-moulded material that clamps it tightly against the tube 20. This also presses the heating wire 27 close to the carrier 28. Because the heating wire 27 is arranged for resistive heating, relatively good heat transfer is achieved. The injection-moulded material also encapsulates the connection between the lead 25b and the heating wire 27 and generally shields the heating wire 27 from the environment.

[0092] In an embodiment, the mass 31 of injection-moulded material may be over-moulded so as to extend to the exterior surface of the tube 20 at at least one end of the heating device 19. This establishes a bond that further contributes to fixing the heating device 19 to the tube 20.

[0093] The injection-moulded material may be a composite such as glass fibre-reinforced polyphenylsulphide. An example is available from Ticona GmbH under the trade mark Fortron 1130L4.

[0094] The carrier 28 and the mass 31 of injection-moulded material may have the same material composition.

[0095] The mass 31 of injection-moulded material has at least one moulded feature on its exterior. In the illustrated example, this includes recessed features for co-operating with pawls 32a,b (FIGS. 3,5) of a cap 33. The cap 33 acts as a clamp to press the thermal fuse 26 tightly into contact with the flange 30 in the illustrated embodiment or the mass 31 of injection-moulded material in alternative embodiments. The cap 33 further closes the space accommodating the thermal fuse 26 and terminals 34a,b connecting it to the heating wire 27 and lead 25a.

[0096] The thermal fuse 26 is an irreversible thermal fuse 26 in the illustrated embodiment. In an alternative embodiment, it is replaced by a temperature sensing device for conducting a signal to the controller 16.

[0097] In use, the power control device 18 is arranged to supply electrical pulses 35a-f to the heating device 19. The voltage of the pulses 35a-f may be 12 V or 24 V, for example. The pulses 35a-f are of different duration and in accordance with a scheme. The controller 16 is configured to select a scheme from among a number of pre-determined schemes in dependence on at least one value of the measurement signal provided by the temperature sensor 17. The temperature sensor 17 may be in close proximity to or in thermal contact with the tube 20 or a different part of the outlet conduit 13, for example. At least a first pulse 35a is of longer duration than at least a final pulse of a sequence corresponding to a scheme. The sequence may have a finite duration and be triggered by an event such as an interaction by a user with the user interface 3, activation of main power switch (not shown) of the dispenser 1 or the elapse of a certain period of time since the last provision of a pulse sequence. The triggering of the provision of the pulse sequence may be temperature-dependent, so that the heating device is operated more frequently at higher ambient temperatures, for example.

[0098] The pulse frequency is relatively low, with the duration of at least the longest pulse 35a being at least one second. Thus, electrical interference and noise are avoided.

[0099] The heating device 19 is operated such that the temperature of the section of the tube 20 along which the heating device 19 is provided remains below 100° C., e.g. below 90° C. This suffices to create a thermal barrier whilst preventing or at least reducing scaling in the tube 20. The outlet section 22 remains below 50° C. to prevent burns, should a user inadvertently touch the outlet 5.

[0100] An example of a method of manufacturing the outlet conduit 13 (FIG. 9) includes an optional step 36 of roughening at least a section of the tube 20, where the heating device 19 is to be fixed in position. In parallel, the heating wire 27 is wound onto the carrier 28 and the leads 25a,b are connected (step 37). Then (step 38), the carrier 28 is slid onto the circle-cylindrical section 21 of the tube 20. Because this section 21 is straight and the tube 20 is relatively short, this step 38 is relatively easy to accomplish. The features, in this case the groove 24, for connecting the outlet conduit 13 to the fitting 14 are all recessed, so that the carrier 28 can have an inside diameter corresponding to the outside diameter of the straight section 21 of the tube 20 to within the chosen tolerance ranges.

[0101] The assembly is then placed (step 39) in a mould (not shown) enclosing at least the section of the outlet conduit 13 corresponding to the heating device 19. The carrier 28 positions the heating wire 27. Injection-moulding 40 fixes the heating device 19 to the tube 20. The assembly is then removed from the mould (step 41), the thermal fuse 26 is connected (step 42) after the injection-moulded material has cooled down. Finally, the cap 33 is attached (step 43).

[0102] The leads 25a,b may be provided with a connector or connectors at their free ends for plugging into sockets of the power control device 18 in the process of mounting the outlet conduit 13 in the dispenser housing 2.

[0103] Due to the robust and secure attachment of the heating device 19 to the tube 20, the outlet conduit can be handled and stored relatively easily prior to mounting in the dispenser 1. The injection-moulded material and the cap 33 shield the sensitive components and connections relatively well.

[0104] The invention is not limited to the embodiments described above, which may be varied within the scope of the accompanying claims. For example, although an example of a resistive heating device 19 has been used, the heating device 19 may be an inductive heating device in another embodiment. In that case, one or more coiled wires forming induction coils replace the heating wire 27.

[0105] In an alternative embodiment using a resistive heating device 19, the heating wire 27 is dispensed with. Instead, the mass 31 of injection-moulded material itself comprises an electrically conducting material or compound. The carrier 28, or an alternative separator having a higher electrical resistivity than the injection-moulded material, separates the electrically conducting material or compound from the tube 20 to prevent short-circuits. A terminal at the end of at least one of the leads 25a,b is embedded in the electrically conducting material. The end of the other lead 25a,b may be connected to the thermal fuse 26 with the latter electrically connected to the electrically con-ducting material or compound on an opposite side of the expanse of injection-moulded electrically conducting material to the terminal at the end of the other lead 25a,b. Alternatively, the thermal fuse 26 may be dispensed with, so that the ends of both leads 25a,b are embedded in the electrically conducting material or compound on opposite sides of the expanse of electrically conducting material. In that case, the electrically conducting material or compound may have a non-linearly increasing temperature-dependent resistivity to allow the thermal fuse 26 to be dispensed with. An example of a suitable material is PTC rubber, a compound made of polydimethylsiloxane loaded with carbon nano-particles.

[0106] In yet another alternative example, a heating foil is used instead of the heating wire 27.

LIST OF REFERENCE NUMERALS

[0107] 1 dispenser [0108] 2 housing [0109] 3 user interface [0110] 4 recess [0111] 5 outlet [0112] 6 inlet fitting [0113] 7 filter system [0114] 8 manifold [0115] 9 pump [0116] 10 cooler [0117] 11 gas supply valve [0118] 12 gas container [0119] 13 outlet conduit [0120] 14 connection fitting [0121] 15 interconnecting conduit [0122] 16 controller [0123] 17 temperature sensor [0124] 18 power control device [0125] 19 heating device [0126] 20 tube [0127] 21 circle-cylindrical section [0128] 22 outlet section [0129] 13 curved section [0130] 24 groove [0131] 25a,b—leads [0132] 26 thermal fuse [0133] 27 heating wire [0134] 28 carrier [0135] 29 upstream flange [0136] 30 downstream flange [0137] 31 injection-moulded part [0138] 32a,b—pawls [0139] 33—cap [0140] 34a,b—terminals [0141] 35a-f—pulses [0142] 36 step (roughen tube) [0143] 37 step (wind heating wire) [0144] 38 step (slide carrier onto tube) [0145] 39 step (place in mould) [0146] 40 step (injection-mould) [0147] 41 step (remove from mould) [0148] 42 step (connect fuse) [0149] 43 step (attach cap)