Steam or hot water generators for coffee machines

Abstract

Steam or hot water generator (9) for coffee machines, comprising a tube (12) having an end (13) for the water inlet and an end (14) for the outlet of steam or hot water, at least one electric heating element (15) extending along the tube (12), an inlet connection (16) attached to the inlet (13) of the tube (12), an outlet connection (17) attached to the outlet end (14) of the tube (12), and a filter (21) integrated with the outlet connection (17), characterized in that the inlet connection (16) and the outlet connection (17) are made of plastic and the filter (21) is made in one piece with the outlet connection (17), wherein the outlet connection (17) has an external circumferential recess (27) in which a seal (28) is accommodated for radial sealing against the tube (12), and wherein the outlet connection (17) has a flange (29),which engages against a flange (30) of the outlet end (14) of the pipe (12), and a fastening clamp (32) is provided which is designed to clamp the flange (29) of the outlet connection (17) against the flange (30) of the outlet end (14) of the pipe (12).

Description

The present invention relates to a steam or hot water generator for coffee machines. A steam or hot water generator for coffee machines typically includes a pipe having one end for the water inlet and one end for the steam outlet, one or more electric heating elements developing along the pipe, an inlet connection attached to the inlet of the pipe, and an outlet connection attached to the outlet end of the pipe. The steam or hot water generator is supplied with water from the coffee machine's hydraulic circuit and heats or superheats it to produce hot water or steam, which is then directed to a hot water or steam dispensing pipe or nozzle normally provided by the coffee machine. One of the biggest problems that a conventional steam or hot water generator has is that limescale deposits can form on the inner wall of the pipe, especially if the water has a high degree of hardness. The limescale deposits can detach from the inner wall of the pipe and impair the proper operation and / or the structural integrity of the components of the coffee machine's hydraulic circuit located downstream of the generator. In particular, limescale deposits that detach from the pipe can clog the nozzle or pipe for steam output, or any solenoid valves located between the generator and the output nozzle or pipe. To eliminate this problem, the pipe is usually cleaned with special descaling agents. The success of descaling to prevent possible damage to the components of the coffee machine's hydraulic circuit, located downstream of the machine, depends on the operator's skill and timely intervention, who must repeat the process regularly when the risk of new limescale deposits forming, which could detach from the pipe, is deemed to be present. This invention is therefore based on the technical problem of providing a steam or hot water generator for coffee machines that enables the elimination of the technical problems that the prior art exhibits. Within the scope of this technical task, one purpose of the invention is to provide a steam or hot water generator for coffee machines that enables the elimination of the risk associated with the impairment of the functional integrity and the functionality of the components of the hydraulic circuit of the coffee machine, which are arranged downstream of the steam or hot water generator, due to limescale deposits that detach from the inner wall of the pipe of the steam or hot water generator. Another object of this invention is to provide a steam or hot water generator which has a design that can be easily disassembled into its essential components in order to enable their simple and quick inspection and cleaning. The technical problem as well as this and other purposes according to the invention are fulfilled by providing a steam or hot water generator for coffee machines with the features of claim 1. In a preferred embodiment of the invention, the filter is positioned in the pipe. In a preferred embodiment of the invention, the filter extends from one end of the outlet connection in the pipe. According to the invention, the filter is manufactured as a single piece with the outlet connection. In a preferred embodiment of the invention, the outlet connection has an internal channel that extends along an axis of the outlet connection, wherein the filter itself has an internal channel that extends along an axis of the filter and is in fluid communication with the internal channel of the outlet connection. In a preferred embodiment of the invention, the internal channel of the outlet connection and the internal channel of the filter extend coaxially. In a preferred embodiment of the invention, the internal channel of the filter extends coaxially to the pipe. In a preferred embodiment of the invention, the filter has a bottom and an inner wall which are equipped with a plurality of calibrated through-openings. In a preferred embodiment of the invention, the filter has a cylindrical shape. According to the invention, the outlet connection has a circumferential recess on the outside in which a seal for radial sealing against the pipe is accommodated. According to the invention, the outlet connection has a flange which engages against a flange of the outlet end of the pipe. According to the invention, a fastening clamp is provided which is designed to clamp the flange of the outlet connection against the flange of the outlet end of the pipe. In a preferred embodiment of the invention, the internal channel of the outlet connection has a widened section and a shoulder section at a point outside the pipe, which define a seat for inserting an external pipe. In a preferred embodiment of the invention, a matrix is ​​provided in which the tube and the heating element are integrated. In a preferred embodiment of the invention, the inlet connection has an element at one end in the pipe which is designed and arranged to divide the incoming water flow. This invention also discloses a coffee machine which has such a steam or hot water generator. Further features and advantages of the invention will become clearer from the description of preferred, but not exclusive, embodiments of the steam or hot water generator according to the invention, which is shown as a non-limiting example in the accompanying drawings. It shows: Fig. 1 a first preferred embodiment of the steam or hot water generator in perspective and partially as an exploded view; Fig. 2 an enlarged section in the cross-section of the generator area from Fig. 1, in which the outlet connection is provided; Fig. 3 in cross-section a second preferred embodiment of the hot water generator, in which the design of the electrical heating elements is highlighted; Fig. 4 the generator from Fig. 3 in cross-section along lines 4-4; and Fig. 5 a possible plan of the hydraulic circuit of a coffee machine that includes the generator. In the following description, equivalent parts of the different embodiments of the invention are specified with the same numerical reference. Referring to the figures mentioned, the hydraulic circuit of the coffee machine 1 comprises, in a known manner and in cascade form, a water source (not shown), which may be the private water network or a corresponding water container, a supply pump 2, a boiler 3, a brewing group 4, defining a brewing chamber in which the coffee dose is positioned, and an external coffee dispenser 5 to dispense the coffee into one or two cups 6 located below and specially positioned on a drip tray 7. The hydraulic circuit of the coffee machine 1 also includes a pipe 8 for supplying water to a steam or hot water generator 9, hydraulically connected to an external steam or hot water outlet 10, which can take the form of a pipe or a dispensing nozzle. The hydraulic circuit of the coffee machine 1 also includes a first solenoid valve 60 with three paths, having one path connected to the outlet of the supply pump 2, one path connected to the inlet of the boiler 3, and one path connected to the inlet of the supply circuit 8, and a second solenoid valve 61 with three paths, having one path connected to the outlet of the generator 9, one path connected to the inlet of the external dispensing spout 10, and one path connected to a drain circuit 62. If it is equipped for steam generation, the external dispensing unit 10 can be associated with a milk container 11 or a device for frothing a quantity of milk to be combined with the coffee contained in the cup 6 to prepare a cappuccino. The generator 9 comprises a tube 12 having an end for the water inlet 13 and an end for the steam outlet 14, at least one electric heating element and in particular two electric heating elements 15 which develop in a diametrically opposite position along the tube 12, an inlet connection 16 which is attached to the inlet 13 of the tube 12, and an outlet connection 17 which is attached to the outlet end 14 of the tube 12. The electrical heating elements 15 comprise resistance elements that are elongated to follow the axial development of the tube 12, in this case, but not necessarily curved. Pipe 12 is made of a thermally conductive material, for example stainless steel. The inlet connection 16 and the outlet connection 17 are preferably made of plastic. The inlet connection 16 has an internal channel 19 along its axis for the inlet of water into the pipe 12, and the outlet connection 17 has an internal channel 20 along its axis L for the outlet of hot water or steam from the pipe 12. The generator 9 also has a thermally conductive matrix 18 into which the tube 12 and the electrical heating elements 15 are integrated. In the illustrated case, with particular reference to Figures 3 and 4, the matrix 18 is a die-cast aluminum block comprising a receptacle 18a for the tube 12 and two receptacles 18b for the electrical heating elements 15. The tube 12 is fixed to its receptacle 18a by soldering, while the electrical heating elements 15 each comprise a resistance element 15a, which is spirally wound and embedded in a silica filler 15b, held in the respective receptacle 18b by means of insulating ceramic covers 15c, which are traversed by electrodes 15d that are electrically supplied by contacts 15e. The matrix 18 can in any case have different shapes, for example the shape of a die-cast aluminum block in which the tube 12 and the electric heating elements 15 are embedded, or the shape of two stainless steel shells in which an armored resistor is in a water bath, or another shape. Advantageously, the generator 9 has a filter 21 which is integrated with the outlet connection 17. The filter 21 is in particular made from a single piece with the outlet connection 17. The filter 21 is positioned in the pipe 12 and extends from one end of the outlet connection 17 in the pipe 12. The filter 21 has an internal channel 22 along its axis L', which is in fluid communication with the internal channel 20 of the outlet connection 17. The internal channel 20 of the outlet connection 17 and the internal channel 22 of the filter 21 extend coaxially. The internal channel 22 of the filter 21, in turn, extends coaxially to the tube 12, with which it defines a space 23. The body of the filter 21, which preferably has a cylindrical shape, is formed from a base 24 and a side wall 25, provided with a plurality of calibrated through-openings 26. The outlet connection 17 has an outer circumferential recess 27 in a section of the pipe 12, in which a seal 28 is accommodated for radial sealing against the pipe 12. The outlet connection 17 also has a flange 29 which engages against a flange 30 of the outlet end 14 of the pipe 12. The flange 29 of the outlet connection 17 and the flange 30 of the outlet end 14 of the pipe 12 are clamped against each other in a groove 31 of a fastening clamp 32. In the embodiment of Fig. 1 and Fig. 2, the fastening clamp 32 is also provided with wings 33 for protection and for guiding the wires for the power supply of the electrical heating elements 15. At a section of the outlet connection 17 outside the pipe 12, the internal channel 20 of the outlet connection 17 has a section 34 with a widened through-cross-section, which ends with a shoulder piece 35 and with the shoulder piece 35 defines a seat 38 for receiving an end of an external pipe 36 for connecting the producer 9 with the external dispensing outlet 10. The external connecting tube 36 is flexible and consists primarily of PTFE, but can alternatively be rigid and made of a different material. At the end of the external tube 36 a bushing 39 is firmly wedged, having an outer surface that is joined to the wall of the section 34 of the internal channel 20 of the outlet connection 17. The bushing 39 has a first end that is offset rearward towards the end of the external tube 36, and an O-ring for radial sealing 40 is positioned on the section of the external tube 36 between its end and the first end of the bushing 39 against the wall of the section 34 of the internal channel 20 of the outlet connection 17. The O-ring for the seal 40 interferes with the shoulder piece 35 in the position where the external tube 36 is inserted furthest into the outlet connection 17. The outlet connection 17 also has a seat 41 for a cotter pin 42 on its section outside the tube 12, which is inserted and positioned on the diameter of the external tube 36 to interfere with a second end of the bushing 39 to prevent the external tube 36 from being pulled out of its seat 38. The inlet connection 16 has a design that is identical to that of the outlet connection 17 already described. In particular, the inlet connection 16 has an outer circumferential recess 43 at a section in the pipe 12, in which a seal 44 is located for radial sealing against the pipe 12. The inlet connection 16 also has a flange 45 that engages with a flange 46 of the inlet 13 of the pipe 12. The flange 45 of the inlet connection 16 and the flange 46 of the inlet 13 of the pipe 12 are clamped against each other in a groove 47 of a retaining clamp 48. In the embodiment of Fig. 1 and Fig. 2, the fastening clamp 48 is also provided with wings 49 for protection and for guiding the wires for the power supply of the electrical heating elements 15. The inlet connection 16 has an internal seat for receiving one end of an external pipe 50 for connecting the generator 9 to the supply line 8. The connection with hydraulic sealing between the external pipe 50 and the pipe 12 by means of the inlet connection 16 is identical to the previously described connection between the external pipe 36 and the pipe 12 by means of the outlet connection 17, whereby in this case too a bushing 51, a cotter pin 52 and an O-ring for radial sealing 53 are used. The most important difference regarding the design of the inlet connection 16 compared to the outlet connection 17 is that there is no filter, but rather an element 54 designed and arranged to divide the incoming water flow. The dividing element 54 is formed from a segment that extends outside one end of the inlet connection 16 into the pipe 12 along the extension of a diametrical plane of the axial channel in the inlet connection 16. The functioning of the generator 9 according to the invention becomes clear from the description and illustration and is essentially as follows. When there is a need for steam or hot water, the operator of the coffee machine 1 activates the electric heating elements 15 and the supply pump 2 to direct jets of water to the generator 9. The water flow entering the generator 9 via the inlet connection 16 is divided by the dividing element 54 and forced to touch the inner wall of the pipe 12, thus improving the efficiency of the generator 9. The steam or hot water generated along the pipe 12 is forced to flow through the filter 21 in order to exit the outlet connection 17 of the generator 9. During the flow through the filter 21, any limescale deposits that have detached from the inner wall of the pipe 12 are filtered by the filter 21 and can later be removed during maintenance by simply disassembling the generator 9 by removing the retaining clip 32 and pulling out the cotter pin 42 to remove the outlet connection 17 and with it the filter 21 from both the pipe 12 and the external pipe 36. The steam or hot water generator for coffee machines, as designed, is subject to numerous modifications and variations, all of which fall within the scope of the invention. Furthermore, all individual parts can be replaced by technically equivalent components. In practice, the materials used and the dimensions can be arbitrary, depending on needs and the state of the art.

Claims

Steam or hot water generator (9) for coffee machines, comprising a tube (12) having an end (13) for the water inlet and an end (14) for the outlet of steam or hot water, at least one electric heating element (15) extending along the tube (12), an inlet connection (16) attached to the inlet (13) of the tube (12), an outlet connection (17) attached to the outlet end (14) of the tube (12), and a filter (21) integrated with the outlet connection (17), characterized in that the inlet connection (16) and the outlet connection (17) are made of plastic and the filter (21) is made in one piece with the outlet connection (17), wherein the outlet connection (17) has an external circumferential recess (27) in which a seal (28) is accommodated for radial sealing against the tube (12), and wherein the outlet connection (17) has a flange (29),which engages against a flange (30) of the outlet end (14) of the pipe (12), and a fastening clamp (32) is provided which is designed to clamp the flange (29) of the outlet connection (17) against the flange (30) of the outlet end (14) of the pipe (12). Steam or hot water generator (9) for coffee machines according to the preceding claim, characterized in that the filter (21) is positioned in the tube (12). Steam or hot water generator (9) for coffee machines according to the preceding claim, characterized in that the filter (21) extends from one end of the outlet connection (17) in the tube (12). Steam or hot water generator (9) for coffee machines according to one of the preceding claims, characterized in that the outlet connection (17) has an internal channel (20) which develops along an axis (L) of the outlet connection (17), wherein the filter (21) in turn has an internal channel (22) which develops along an axis (L') of the filter (21) and is in fluid communication with the internal channel (20) of the outlet connection (17). Steam or hot water generator (9) for coffee machines according to the preceding claim, characterized in that the internal channel (20) of the outlet connection (17) and the internal channel (22) of the filter (21) extend coaxially. Steam or hot water generator (9) for coffee machines according to one of claims 4 and 5, characterized in that the internal channel (22) of the filter (21) extends coaxially to the tube (12). Steam or hot water generator (9) for coffee machines according to one of claims 4 to 6, characterized in that the filter (21) has a bottom (24) and a side wall (25), provided with a plurality of calibrated through-holes (26). Steam or hot water generator (9) for coffee machines according to one of the preceding claims, characterized in that the filter (21) has a cylindrical shape. Steam or hot water generator (9) for coffee machines according to one of claims 4 to 8, characterized in that the internal channel (20) of the outlet connection (17) has a widened section (34) and a shoulder (35) at a section outside the tube (12), which define a seat (38) for inserting an external tube (36). Steam or hot water generator (9) for coffee machines according to one of the preceding claims, characterized in that it has a matrix (18) in which the tube (12) and the heating element (15) are integrated. Steam or hot water generator (9) for coffee machines according to one of the preceding claims, characterized in that the inlet connection (16) has an element (54) at one end in the pipe (12) which is designed and arranged to divide the incoming water flow. Coffee machine, characterized in that it has a steam or hot water generator (9) according to one of the preceding claims.

Images