Device and method for impregnating a candle wick and molding device for a candle

Abstract

Device for impregnating a candle wick over a partial length (TL) with an impregnating agent that interrupts the wax transport in the wick, comprising - a wick feeder (4) for a wick strand (6), characterized by - a dosing system (9) for spraying a UV-curable impregnating liquid acting as an impregnating agent onto the wick part length (TL) of the wick strand (6) with an impregnating liquid feed (12) and a spraying device (10) for the impregnating liquid, and - a UV exposure device (14) arranged downstream of the dosing system (9) for curing the impregnating liquid in the sprayed wick part length (TL).

Description

[0001] The invention relates to a device and a method for impregnating a candle wick over a partial length with an impregnation that interrupts the wax transport in the wick, as well as to a molding device for a candle in which the impregnation device according to the invention is used with the corresponding method.

[0002] Regarding the background of the invention, it should be noted that increased safety awareness in households and businesses has led to increased demands on candles. To reduce the risk of fire, candles should be self-extinguishing, meaning that at the end of the candle's burning time, the burning wick must not come into contact with the candle's surroundings. Rather, the candle must extinguish itself before reaching such a critical state.

[0003] Various measures for this purpose are known from the prior art, some of which are based on the use of additional mechanical elements, such as wick sleeves or candle holders on the base of the candle. Examples include DE 10 2005 058 108 A1, EP 1 792 971 A1, WO 03 / 016443 A1, or DE 10 2006 007 864 A1. A disadvantage of such candles is the fact that self-extinguishing is achieved by an additional component in the candle, which entails additional manufacturing effort. This is disadvantageous for a mass-produced item such as a candle for both manufacturing and economic reasons.

[0004] An alternative measure for achieving the self-extinguishing properties of a candle is described in DE 24 15 652 A1, according to which the wick is impregnated at its lower end with an agent that eliminates its absorbency. This document discloses the use of organic polymers as impregnating agents, which can be applied to the wick end in dissolved, dispersed, or molten form, or as precondensates, and optionally fixed in a non-detachable and infusible manner by thermal post-treatment. These impregnating agents must be able to penetrate the wick material and eliminate the absorbency of the wick by filling the pores and fiber interstices.

[0005] DE 20 2009 005 676 U1 teaches embedding the lower end of the wick in a molded body made of a mineral bulk material and a binder. The use of a sheath made of a natural, biodegradable material in the area of ​​the lower end of the wick is also known, namely from WO 97 / 30138 A1.

[0006] Finally, EP 2 628 783 B1 discloses impregnating a partial length of the wick by injecting the impregnating agent into the wick using an injection needle inserted from the side. The design effort for this technique is relatively high due to the control of the movable injection needle. Furthermore, the arrangement is also relatively sensitive mechanically.

[0007] Based on the problems of the prior art described above, the object of the invention is to provide a device and corresponding process engineering procedure that are particularly suitable for impregnating a candle wick over a partial length, which achieves a high level of reliability in production use and in the fire protection properties of the candles produced therewith using simple construction means.

[0008] This object is achieved by a device having the features specified in the characterizing part of claim 1 using a corresponding method according to the characterizing part of claim 12. The device accordingly has - a wick feeder for one wick strand, - a dosing system for spraying a UV-curable impregnating liquid acting as an impregnating agent onto the wick section of the wick strand with an impregnating liquid feed and a spraying device for the impregnating liquid, as well as - a UV exposure device downstream of the dosing system for curing the impregnating liquid in the sprayed wick part length (TL).

[0009] The characteristic features of the process are - Spraying a UV-curable impregnating liquid acting as an impregnating agent onto the wick part length (TL) of the wick strand, and - Curing of the impregnating liquid applied to the wick section by exposure to UV light.

[0010] The invention is distinguished from the prior art in that the impregnating liquid is applied by simple spraying, which—preferably with the aid of appropriate application nozzles—can be easily integrated into a wick feeder without the need to soak the wick by immersing it in a liquid. Furthermore, the wetting of the wick strand with the impregnating agent and its fixation can be accomplished in a short period of time due to the use of a liquid that generally hardens quickly under the influence of UV light, thus enabling the corresponding impregnating device to be easily integrated into a high-performance candle production system.

[0011] Preferred embodiments of the invention provide for the wick feeder to have a retractable wick supply, a preferably incremental wick position measuring device, and a wick alignment device with a wick detector. This supports the precise positioning of the wick strand into the dosing system with precise feed speed, which benefits the exact positioning of the impregnated partial length in the wick strand.

[0012] The application nozzles mentioned can be operated by compressed air or piezoelectric means, for which commercially available, proven components can be used.

[0013] Standard UV-curable printing ink has proven particularly suitable as an impregnating fluid. Therefore, a commercially available, field-tested product can be used for this special purpose.

[0014] In order for the device according to the invention to comply with relevant safety and occupational health and safety regulations, the UV exposure device is preferably arranged in the form of a UV lamp, such as a UV LED lamp, in a light-tight chamber.

[0015] Especially when using UV-curable printing inks as impregnating fluids, a UV light wavelength range of 380 nm to 400 nm, especially 385 nm to 395 nm, has proven advantageous. Affordable, effective UV lamps are readily available for this wavelength range.

[0016] From a process engineering perspective, the exposure can be carried out at a maximum feed rate of the wick strand of 30 m / min, preferably 10 m / min to 20 m / min, particularly preferably 15 m / min. These specifications also allow for trouble-free integration of the wick impregnation according to the invention into a high-performance candle production plant.

[0017] According to a further advantageous embodiment of the invention, a fan is arranged in the chamber accommodating the UV exposure device to ensure sufficient air exchange.

[0018] For further fixation of the UV-curable impregnating liquid, a second UV exposure device can be provided for post-exposure of the wick embedded in a candle.

[0019] Finally, the invention relates to a molding device for the mechanical production of a self-extinguishing candle comprising - a candle pressing station with hydraulic cylinder, wax compactor, inlet for a prefabricated wick strand and forming unit for a candle blank, - a separating device downstream of the candle pressing station for separating the candle blank into separate candles, and - a wick strand impregnation device according to the invention arranged in front of the candle pressing station, from which the wick strand can be introduced into the candle pressing station via the inlet.

[0020] With regard to the impregnation of the wick strand, the advantages discussed in detail above apply to this system.

[0021] Further features, details and advantages of the invention will become apparent from the following description of an embodiment with reference to the accompanying drawings. It shows the only Fig. 1 a schematic diagram of a molding device for the mechanical production of self-extinguishing candles.

[0022] As can be seen from the drawing, the candle forming device shown has several main parts, namely - each outlined in dashed lines - an impregnation device 1, a candle pressing station 2 and a separating device 3 arranged downstream of this.

[0023] The impregnation device 1 has a wick feed 4, in which a rewindable wick supply 5 is provided in the form of a winding roll. From this, an endless wick strand 6 is drawn via an incremental wick position measuring device, for example, an incremental sensor roll 7, under the influence of the candle pressing station 2. A wick alignment device 8 is arranged downstream of the position measuring device, with the aid of which the wick strand 6, which is flat in cross-section, is introduced into a downstream dosing system 9 with its plane orientation and positioning along the strand feed direction in a defined manner. The dosing system 9 has a spraying device 10 with two application nozzles 11 arranged head-to-head on either side of the wick strand 6, which are supplied with an impregnation liquid from an impregnation liquid supply 12. If sufficient in practice, only one application nozzle 11 can be used.Valve symbols 13 in the impregnation liquid supply 12 indicate that the wick strand 6 can be sprayed with the impregnation liquid via the application nozzles 11 as it passes over a specific partial length TL. The timing of the spraying process is based on the data determined by the sensor roller 7 regarding the time-dependent feed length of the wick strand 6, from which the wick speed can be determined. The impregnation liquid is commercially available UV-curable printing ink, which is sprayed onto the wick strand 6 in an amount of, for example, 50 mg to 80 mg over a partial length TL of 30 mm at a distance of 280 mm. The total product speed can be, for example, 30,000 mm / min.

[0024] A UV exposure device 14 is arranged downstream of the dosing system 9, which is equipped with a UV LED lamp 15 with a light wavelength of 395 nm. The partial length TL of the wick strand 6, previously sprayed with the UV impregnation liquid, is exposed here at a feed rate of a maximum of 30 m / min, preferably 10 m / min to 20 m / min, particularly preferably 15 m / min, and is thus fixed in the wick material by appropriate UV curing.

[0025] The thus prefabricated wick strand 6 is then introduced into the candle pressing station 2 via its wick strand inlet 18, which conventionally comprises a hydraulic cylinder 16, a wax compactor 17, and a shaping unit 19 with a so-called caliber head and die. There, a candle blank 20 is produced with a length equal to several individual candles 21, with the wick strand 6 embedded therein. This wick strand 6 is separated into the individual candles 21 by means of the separating device 3 with conventional separating knife drums 22. In these drums, the impregnated partial length TL is arranged in the candle base area, so that a low-burning candle automatically extinguishes upon reaching this partial length TL due to the non-combustible impregnation.

[0026] To further stabilize the UV-fixed impregnation liquid, a second UV exposure device 23 is provided downstream of the separating device 3, which in turn is equipped with a UV LED lamp 15. This exposes the correspondingly impregnated partial length TL of each individual candle 21 and further fixes it accordingly.

[0027] Both UV exposure devices 14, 23 are enclosed in a light-tight chamber 24 with corresponding, not shown, insertion and removal means for the wick strand 6. The chambers 24 are equipped with a fan 25 for supplying ambient air to control the temperature in the chamber, so that no active cooling is necessary.

Claims

[1] Device for impregnating a candle wick over a partial length (TL) with an impregnating agent interrupting the wax transport in the wick, comprising - a wick feeder (4) for a wick strand (6), characterized by - a dosing system (9) for spraying a UV-curable impregnating liquid acting as an impregnating agent onto the wick part length (TL) of the wick strand (6) with an impregnating liquid feed (12) and a spraying device (10) for the impregnating liquid, and - a UV exposure device (14) arranged downstream of the dosing system (9) for curing the impregnating liquid in the sprayed wick part length (TL). [2] Device according to claim 1, characterized by that the wick feed (4) has a windable wick supply (5), a preferably incremental wick position measuring device and / or a wick alignment device (8) with wick detector. [3] Device according to claim 1 or 2, characterized by that the dosing system (9) for the impregnating liquid has at least one application nozzle (11) which sprays the wick strand (6) with impregnating liquid and which is supplied with the impregnating liquid by a liquid supply device (12). [4] Device according to claim 3, characterized by that the at least one application nozzle (11) is operated by compressed air or piezoelectrically. [5] Device according to one of the preceding claims, characterized by that the UV exposure device (14) has a UV lamp, preferably a UV LED lamp (15), arranged in a preferably light-tight chamber (24). [6] Device according to claim 5, characterized by that the UV lamp (15) emits UV light with a wavelength of 380 nm to 400 nm. [7] Device according to claim 5 or 6, characterized bythat the chamber (24) has a fan (25) for air exchange. [8] Molding device for the mechanical production of a self-extinguishing candle, comprising - a candle pressing station (2) with hydraulic cylinder (16), wax compactor (17), introduction (18) for a prefabricated wick strand (6) and shaping unit (19) for a candle blank (20), and - a separating device (3) arranged downstream of the candle pressing station (2) for separating the candle blank (20) into separate candles, characterized by - a wick strand impregnation device (1) according to one of claims 1 to 9 arranged in front of the candle pressing station (2), from which the wick strand (6) can be introduced into the candle pressing station (2) via the inlet (18). [9] Molding device according to claim 8, characterized by that a second UV exposure device (23) for post-exposure of the candle wick is arranged after the separating device (3). [10] Method for impregnating a candle wick over a partial length (TL) with an impregnating agent that interrupts the wax transport in the wick, characterized by - spraying a UV-curable impregnating liquid acting as an impregnating agent onto the wick part length (TL) of the wick strand (6), and - Curing of the impregnating liquid applied to the wick part length (TL) by exposure to UV light. [11] Method according to claim 10, characterized by that a UV-curable printing ink is used as the impregnating liquid. [12] Method according to claim 10 or 11, characterized by that UV light with a wavelength of 380 nm to 400 nm is used. [13] Method according to one of claims 10 to 12, characterized by that the exposure takes place at a feed speed of the wick strand (6) of a maximum of 30 m / min, preferably 10 m / min to 20 m / min, particularly preferably 15 m / min.

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