FR2781875A1 - Fabrication procedure and device for the production of ice cubes - Google Patents

Abstract

The device comprises a tray (7) that is in the shape of the cubes and is in thermal contact with a thermoelectric module (16). Water is fed by conduits (8,9) to the tray and frozen to form the cubes. A refrigeration unit comprising an evaporator (10), compressor (3) and condenser (4) is incorporated. An Independent claim is included for a procedure of producing ice cubes using the described apparatus.

Description

The present invention relates to a device for

making ice cubes.

  The professional ice making machines on the market, which are generally intended for restaurateurs and distributors of beverages, use a compression refrigeration system, in which the energy captured in the water used to form the ice cubes is evacuated either by means a ventilated condenser, either by means of a waste water dissipator, the demoulding of the ice cubes being

  made using the group's hot gases.

  The main drawback of the ventilated condenser system is that the efficiency of the cooling unit decreases while the ambient air temperature increases, which reduces the production of ice cubes during the most intense periods.

hot of the year.

  For its part, although it is also sensitive to temperature variations, the wastewater system allows

  to obtain a better yield, but it consumes on average one liter of network water per minute to produce approximately 20 20 kg of ice cubes per 24 hours. This results in a high operating cost for the user.

  In addition, very few commercially available icemakers make it possible to make less than 20 kg of icicles per day and, since their components are the same as those of a machine with higher efficiency, the costs of production remain important and, consequently, the cost price of these machines is dissuasive for a number of small outlets of drinks. To overcome some of the drawbacks of known systems, and in particular to have an ice machine suitable for users with a daily need of only 5 to 15 kg of ice, namely not only small restorers and dispensers, but also

  caterers, small communities, and even individuals, 35 ice makers have been operated using the Peltier effect.

  The Peltier effect is a well known thermoelectric effect, which leads either to an absorption, or to a release, of heat at the junction of two arms of conductive materials crossed by a current, according to the direction of passage of the current in the junction, the quantity of

  heat being proportional to the intensity of the current.

  In practice, the two arms of material are joined together for metallic copper connections which form, at one end of the arms, a hot weld at the level of which heat is released and, at the other end of the arms, a cold weld at the level at which heat is absorbed, the cold junction becoming hot junction, and vice versa, when the direction of current flow is reversed. Several couples of this type are generally mounted in series

  electric and thermal parallel to form a thermoelectric module.

  Among the ice makers using the Peltier effect, one can cite the one disclosed in FR-A-2 747 769 which comprises an ice-shaping tray supplied with water and a thermoelectric module with Peltier effect, in contact with said tray and intended for making ice cubes and simultaneously producing fresh water. The heat exchanger in contact with the hot face of the thermoelectric module is an air dissipator which is preferably provided with fins to dissipate heat more effectively. The ice cubes are removed from the mold by reversing the polarity of the said module. The air dissipation used in this machine is, with waste water dissipation, the only mode of heat dissipation recommended by the manufacturers of thermoelectric modules. However, this type of heat dissipation does

  does not allow a satisfactory ice cube yield to be obtained, which may explain why the aforementioned machine has not yet been marketed to date.

  The object of the invention is therefore to propose a new device for manufacturing ice cubes which does not have the drawbacks of the prior art and which offers, in particular, sufficient energy dissipation to produce up to 15 kg of ice cubes. per 24 hours, while having an acceptable cost price and a reduced footprint5. Another object of the invention is to propose a device for manufacturing ice cubes which can be obtained by rapid assembly of simple pieces, thus guaranteeing its reliability. These objects are achieved by the invention in the sense that it proposes a device for the production of ice cubes comprising: an ice-shaping container in thermal contact with a Peltier thermoelectric module, means for supplying water to said container and means for inverting the polarity of said module, to go from a freezing mode to a mode for removing mold from the ice cubes, characterized in that said device also comprises a circuit for cooling the hot face,

  freezing mode, of said module, which circuit comprises a coolant evaporator mounted in a closed circuit with a compressor and a condenser.

  According to a first embodiment of the invention, said evaporator is in thermal contact with the hot face of the thermoelectric module. The evaporator is therefore directly used to cool the hot face of said module. To reduce the size of the device so that it can be housed in a refrigerator, and to lower its cost, the compressor and the condenser can be those belonging to the refrigeration unit of a refrigerator.30 According to a second embodiment, the device according to the invention further comprises: - at least one coolant dissipator in thermal contact with the hot face of the thermoelectric module, and preferably a dissipator par35 thermoelectric plate, - a reserve of water suitable for forming a bank of ice on said evaporator, and - means for passing said cooling fluid over said evaporator, then through said dissipator. The evaporator is therefore indirectly used for

  cool the hot side of said module.

  Advantageously, the device according to the invention further comprises: - means for closing the ice-cube tray, which is rotated by a first control cam, fixedly mounted on a motor shaft, between a position for closing said tray and a position spaced from said tray, and - means for controlling the reversing means, which comprises a second control cam fixedly mounted on said shaft. The closure means of the container guarantees the formation of ice cubes of regular shape, without drips, and in particular prevents that ice cubes formed simultaneously in adjacent cavities of the shaping container are not welded

  each other. In addition, the pivoting of the closure means and the reversal of the polarity of the thermoelectric module and, consequently, the formation and demolding25 of the ice cubes, can be done entirely automatically.

  In a first variant of the invention, said closure means simply consists of a closure plate. In a second variant of the invention, which makes it possible to obtain more transparent ice cubes, said closure means consists of a water tank in which are injectors facing towards said ice shaping tank. The invention also relates to a method for manufacturing ice cubes, comprising the steps consisting in: a) supplying water to an ice cube tray, b) transforming said water into ice cubes by passing a current through at least one module thermoelectric with Peltier effect, the cold face of which is in thermal contact with said container, 5 c) reversing the direction of current flow through said module, so as to demold said ice cubes, and d) recovering said ice cubes thus demolded, characterized in that it further consists in cooling, directly or indirectly, the hot face of said module, by

  freezing mode, by evaporation of a cooling liquid generated by compression and condensation of a cooling gas.

  In a first embodiment of the invention, in which the evaporation of the coolant cools

  directly the hot face of the thermoelectric module, on15 passes said coolant through an evaporator in thermal contact with the hot face of said module.

  In a second embodiment of the invention, in which the evaporation of the coolant indirectly cools the hot face of the thermoelectric module, the method according to the invention comprises the steps consisting in: - using said evaporation to freeze water in an ice bank, - passing a cooling fluid over said ice bank, to cool said fluid, and - passing said cooling fluid thus cooled through a dissipator in thermal contact with the hot face of said module. Advantageously, the method according to the invention further comprises the steps consisting: - before step (a), of closing said container by a closing means, and - before step (d), of moving said closing means from a closed position of said tank to

a position spaced from said tray.

  The invention will now be described with reference to the following detailed description, taken in combination with the

  attached drawings in which: Figure 1 is a schematic side view of an ice-making device according to an embodiment of the invention; Figure 2 is a schematic side view of an ice-making device according to another embodiment of the invention; Figure 3 is a partial schematic front view of the device illustrated in Figure 1 or 2; Figure 4 is a schematic front view of the mechanical part of the device shown in Figure 1 when the ice bin is cooling; Figure 5 is a view similar to Figure 4 taken when filling the ice bin ; and FIG. 6 is a view similar to FIG. 5, illustrating a variant of the means for closing the container

  In the following description, identical reference numerals identify identical structural elements,

  while identical reference numerals, but followed by the prime sign, designate similar structural elements. 25 Referring first to FIG. 1, it can be seen that the device for making ice cubes 1 according to this form of the invention comprises a refrigeration unit 2, conventionally consisting of a high-medium pressure compressor 3, of the HMP R 124 A type, for example 30 marketed by ELECTROLUX, associated with a ventilated condenser 4 and, via the pipes 11 , 12 coolant, at a

coil evaporator 10.

  The device 1 further comprises a collection chamber 6 which is intended to receive ice cubes falling by gravity from an ice-shaping container 7. As illustrated in FIG. 4, the shaping container 7 contains a temperature probe 37 and two rows of cavities 44 open downwards, each of which contains a level probe 38. The function of probe 37 is to control the temperature of the plates 16 (FIG. 1) in order, on the one hand, to control the release of the ice cubes which will be formed in tray 7 (as will be described in detail below) and,

  on the other hand, protect the wafers 16 by cutting the overall electrical supply of the device according to the invention and possibly also actuating an audible and / or light signal, in the event that the temperature exceeds, for example, 60 vs.

  Returning to FIG. 1, it can be seen that the shaping tank 7 is supplied with mains water, via the solenoid valve 8, through line 9 which passes through a cooling tank 5 containing the evaporator 10. It is indeed understood, however, that instead of being supplied by the network, the water circulating in the pipe 9 can come from a water reserve (not shown), in particular in cases where water is scarce and / or expensive. As a variant or in addition, the water 20 intended for the formation of ice cubes can be introduced into the shaping tank 7 without prior passage into the cooling tank 5. In the case where a reserve of water is placed immediately above the tank 7, the solenoid valve 8 can be a solenoid of the tube pinch type. A pump 13 is provided for circulating in a closed circuit a cooling fluid, which can be gaseous or liquid - the liquids being preferred because of their better heat transfer power, in the device 1. This cooling fluid can for example be water. The cooling fluid, which arrives at the pump 13 via the line 14, is directed by the pump, via the line 17, through a series of heat sinks, such as 15, each of which is in thermal contact with a Peltier thermoelectric plate, such as 16.35 As best seen in Figure 4, for example, each of the dissipa teurs 15, which generally consists of an aluminum block, is provided with a central fluid inlet, the incoming fluid jet being oriented perpendicular to the hot face of the respective plate 16. The inventors, who have developed this type of dissipator, have discovered that it makes it possible to better capture the energy released by the wafers than conventional dissipators, consisting of a block of copper provided with channels in which the fluid cooling circulates parallel to the hot side of the pads. The use of conventional heatsinks is not, however, excluded in the present invention. These dissipators, as well as the plates 16, are for example available from EQUIPEMENT SCIENTIFIQUE, Garches, FRANCE. The set of plates, such as 16, forms a thermoelectric module in thermal contact with the tray 15 of ice-maker 7. After passing through the dissipators, such as 15, the cooling fluid is discharged into line 18, then passes over the evaporator 10 before being sucked in again by the pump 13. The fact that the coolant circulates in a closed circuit through device 20 allows, when this fluid is tap water, to make substantial savings in the regions of use of the device where water is scarce and / or expensive. In addition, the passage of the cooling fluid over the evaporator 10 makes it possible to maintain this fluid at low temperature (as will be described below), which has the effect of keeping the thermoelectric plates at the

  desired power, and therefore to obtain a suitable ice yield, in very hot ambient environments or during the hottest periods of the year, when the mains water can sometimes exceed 20 C.

  FIG. 2 illustrates a device for manufacturing ice cubes 1 ′ according to the invention, which differs from that illustrated in FIG. 1 by the type of heat dissipation used to cool the thermoelectric plates 16.35 In this figure, it can be seen that, if the compressor 3 is always mounted in series with the ventilated condenser 4 and an evaporator, the evaporator used in this embodiment has substantially a parallelepiped shape and it is directly in contact with the thermoelectric plates 16, thus acting as a single dissipator 5 15 'to absorb, by evaporation of the coolant passing therethrough, the heat produced by the plates 16 in freezing mode, that is to say during the formation of ice cubes. The cooling liquid is brought into the dissipator 15 'by means of a capillary tube 11' which is adapted to regulate the quantity of cooling liquid admitted into the dissipator 15 'as a function of the heat to be absorbed. A dehydrator 43 is further connected between the outlet of the condenser 4 and the capillary tube 11 '. The heatsink 15 'is made of a thermally conductive metal such as copper, possibly combined with a thin layer of heat-conducting jelly capable of

  to accumulate the frigories resulting from the evaporation of the coolant in the dissipator 15 ′ and, by transmitting them to the plates 16, thus allowing continuous cooling of the plates.

  The device illustrated in FIGS. 1 and 2 is much more compact than traditional ice machines, the current minimum dimensions of which are approximately 70 cm high by 35 cm wide and 45 cm deep. We were thus able to produce a prototype of the device represented in FIG. 1, which had a height of 42 cm, a width of 35 cm and a depth of 35 cm - most of this volume being used for the collection chamber 6 -, and whose total weight did not exceed 10 kg. This prototype, with a cooling power of 280 W, made it possible to produce 1,300 to 1,400 ice cubes per day. The device illustrated in FIG. 2 has the advantage of being even more compact - a prototype having a height of approximately 44 cm, a depth of approximately 31 cm and a width of approximately 24 cm has thus been produced - and, furthermore, less expensive than that shown in FIG. 1, insofar as it uses neither a pump nor a coil evaporator. Its cost and its size can be further reduced by using as compressor 3 and condenser 4 those conventionally equipping the refrigeration unit of a traditional refrigerator, the ice-making device according to the invention can then be placed in the refrigerator to deliver ice cubes. automatically, like "American" refrigerators. Turning now to FIG. 3, it can be seen that the ice-making device illustrated in FIGS. 1 and 2 further comprises an electronic card 20, controlling the operation of the device, as well as a transformer 19 associated with a rectifier bridge 21, adapted to lower the supply voltage to 50 V in alternating current and to transform it (a) into a voltage of 12 V in direct current for supplying the card 20, and (b) at a voltage of 60 V direct current for supplying the thermoelectric plates 16. A device 22 for reversing the polarity of the plates is also provided in the vicinity of the electronic card 20.20 The device for making ice cubes illustrated in the figures 3 to 5 also comprises a closure plate 23 of the shaping tank 7, urged in rotation about a pivot axis 25 by a push pin 24 which is integral with a control cam 26. The cam 26 is mounted fixed e on a motor shaft 27 on which is also mounted a polarity reversal cam 28, which has substantially the shape

  of a disc having a cutout 28a (FIGS. 4 and 5) giving it a "camembert" shape. The reversing cam 28 is provided with a control lever 29 adapted to act on micro-contacts 30 (Figures 3 and 4), 41 and 42 (Figure 5). The operation of this mechanical device will be described below.

  after. FIG. 6 illustrates a variant of the means for closing the ice cube tray, in which the closure plate 23 shown in FIGS. 3 to 5 is replaced by a water tank 31 in which two injector rails are arranged,

  such as 32, facing the ice cube maker 7.

  The water tank 31 is supplied with water via the pipe 33 and the water level in the tank 31 is measured by a water level probe 36 known to those skilled in the art. The water is sucked in from the tank 31 by the pump 35 and discharged, via the common line 34, to the injectors, such as 32. The ice cubes produced according to this embodiment of the invention will be more transparent, in the measure o, being formed by successive layers, they contain fewer air bubbles. The operation of the ice-making device according to the invention will now be described with reference to FIGS. 1 and 3-5. When the device illustrated in FIG. 1 is started up, only the cold group 2 is activated. The evaporation of the coolant compressed by the compressor 3 and condensed by the condenser 4, results in an absorption of heat on

  the surface of the evaporator 10. The water initially located in the cooling tank 5 is thus partially frozen, which allows an ice bank 40 to accumulate on the evaporator 10.

  The control cam 28 is then in the position illustrated in FIG. 4, in which its recessed area 28a is exposed to the polarity reversing microswitch 30, so that no contact is made with the latter and that the direction of current flow in the plates 16 is such that the cold face of the latter is in contact with the shaping tank 7, which is thus cooled. The motor shaft 27 is then rotated in the direction of arrow F1, so that it drives with it the control cam 26 and, consequently, the push pin 24 which urges the shutter plate 23 up to 1 '' bring, after a rotation of 125, in the position illustrated in Figure 5, in which it closes the bottom of the shaping tank 7. In this position, the control lever 29 comes into contact35 with the opening microswitch 41 solenoid valve (not shown in Figure 4 so as not to overload it), which controls the filling of the shaping tank 7 via the solenoid valve 8 (Figure 1). About a second later, the motor controlling the rotation of the cam 26 (FIG. 5) is cut by the coming into contact of the lever 29 with the microswitch 42 controlling the stopping of the motor then, once the maximum level of water in the shaping tank 7 has been detected by the level probes 38, the solenoid valve 8 (FIG. 1) is itself closed. The device is therefore in freezing mode, in which ice cubes 39 are formed. Throughout their formation, the hot face of each thermoelectric plate 16 is cooled by passing, through the dissipator 15 in thermal contact therewith, a cooling fluid, such as water, sent by the pump. 13 (FIG. 1), through the line 17, the fluid being returned after each passage, via the line 18, into the tank 5, and therefore onto the evaporator 10, to be cooled by the ice bank 40 formed on the latter then returned, via line 14, to pump 13. 20 Once the temperature probe 37 (FIG. 5) has detected a temperature of -15 ° C., a time relay (not shown) is energized. The relay is adjustable using a potentiometer (not shown) on which the user can act to choose the ice formation time, either directly or by choosing a desired size of ice. Once this time has elapsed, the timer restarts the motor controlling the various functions of the ice-making device according to the invention, thus causing the rotation of the motor shaft 27 and therefore of the reverse polarity cam 28 according to arrow Fl. The circular peripheral region of the cam 28 then comes into contact with the polarity reversal microswitch 30 (FIG. 4), which actuates the polarity reversal device 22 (FIG. 3), thus resulting by reversing the direction of current flow in the thermoelectric plates 16, the hot face of which becomes the face in contact with the shaping tank 7, and therefore by detachment of the ice cubes 39 previously formed. Simultaneously, the control cam 26 rotates according to arrow F1, which has the effect of putting the push pin 24 out of engagement with the shutter plate 5. The plate 23 is then free to pivot around the axis 25 until it returns to the position illustrated in FIG. 4. The ice cubes 39 formed then fall by gravity into the collection chamber 6 (FIG. 1). After 250, or for example 30 seconds, of additional rotation of the motor shaft 27, the cams 26 and 28 are found in the position shown in FIG. 4 and a new cycle for making / demolding ice cubes can then begin. Once the collection chamber 6 (FIG. 1) is full, a thermostatic detector (not shown) cuts the overall supply of the device according to the invention, except the cold group 2, so as to allow the possible regeneration of the bench of ice 40 and, thus, the accumulation of an amount of energy of about 80 KCal / kg. The device illustrated in Figure 2 operates in the same manner as what has just been described with reference to Figures 1 and 3-5, except that in freezing mode, the hot face of the thermoelectric plates 16 is cooled by the dissipator 15 ′ operating by evaporation of a coolant, the coolant thus formed being returned, via line 12 ′, to the compressor 3, where it is compressed before being condensed by the ventilated condenser 4, then dehydrated by the dehydrator 43 and finally returned, via the capillary tube 11 ', to the dissipator / evaporator 15'. In addition, in the case where the variant illustrated in FIG. 6 is used as the means for closing the tank 7, the operation, described above, of the device according to the invention will only be modified in that the microswitch 41 d the solenoid valve opening (Figure 5) will not directly control the filling of the shaping tank 7, but that of the water tank 31, until the water level reaches the level probe 36. At this time, the pump 35 will be actuated, thus expelling water, through injectors such as 32, in the shaping tank 7 maintained at low temperature by the thermoelectric plates 16. It is therefore understood that the ice cubes will form, according to this variant of the invention, in successive layers, which will guarantee their transparency. We also understand that the excess water in

  the water tank 31 will be evacuated during the pivoting of the water tank 31 to a position similar to that occupied by the closure plate 23 in FIG. 4.

  The performance of the device according to the invention was evaluated in the following tests, which were carried out using different types of heat sinks to cool the hot face of the thermoelectric pads used in this invention, with a view to comparing the ice yield of the devices according to the two embodiments of the invention (using respectively the ice bank dissipator illustrated in FIG. 1 and the direct expansion dissipator illustrated in FIG. 2) described above, with the efficiency of ice machines 20 whose the wafers are simply cooled by waste water or by water, circulating in a closed circuit, cooled by a ventilated radiator. The results of these tests are collated in the following table, in which "Start temperature" and "Exit temperature" indicate respectively the initial and final temperatures of the cold face of the thermoelectric plates; "Weight

  of ice "indicates the total weight of ice cubes obtained;" Time "indicates the time necessary to obtain this weight of ice; and" Yield "indicates the ratio of the weight of ice to time.

BOARD

  TYPE OF TEMP. flow Temp. output Weight of Time Efficiency A waste water '+ 22.0 -10.9 200 31 9.2 cooled +12.6 -0.5 none 26 by ventilated radiator 2 A water in cooled circuit +17.3 -15.5 200 15 19, 1 closed by ice bank Direct expansion + 16.4 -14.8 l 240 13 26.4 Initial water temperature = 12.8 C flow rate = 0.7 1 / min 2 Initial water temperature = 9.3 C final water temperature = 23.4 C pump flow 3 1 / mnn water reserve of 8 1. Additional tests, carried out using conventional air dissipation to cool the hot side of the thermoelectric pads, have shown that this type of dissipation does not make ice cubes in a reasonable amount of time. This is due to the fact that the temperature difference AT between the hot and cold faces of the pads, which directly controls the cooling capacity of the machine, could not be lowered sufficiently by this means. It was indeed discovered that, if an AT of 15 C generated a cooling power of 45 W, this power fell to 39 W for an AT of 20 C and to 28 W for an AT of 30 C. The machine thus produced was in besides very

  sensitive to variations in ambient temperature.

  It appears from the preceding table that the ice-making device according to the invention has a higher ice yield than that of ice makers.

  using traditional heat sinks.

Claims (11)

  1. Device for the production of ice cubes, comprising an ice-shaping tank (7) in thermal contact with a thermoelectric module (16) with Peltier effect, water supply means (8,9; 8 ', 9') of said container (7) and of means (22.30) for reversing the polarity of said module (16), in order to pass from a freezing mode to a mode for removing mold from the ice cubes, characterized in that said device (1 , 1 ') further comprises a circuit for cooling the hot face,   freezing mode, of said module (16), which circuit comprises a coolant evaporator (10; 15 ') mounted in a closed circuit with a compressor (3) and a condenser (4).   2. Device according to claim 1, characterized in that said evaporator (15 ') is in thermal contact with the hot face of said module (16). 3. Device according to claim 2, characterized in   that said compressor (3) and condenser (4) belong to the refrigeration unit of a refrigerator.   4. Device according to claim 1, characterized in that it further comprises: - at least one coolant dissipator (15) in thermal contact with the hot face of said module (16), - a suitable water reserve forming an ice bank on said evaporator (10), and means (13,17,18) for passing said fluid   cooling on said evaporator (10), then through said dissipator (15).   5. Device according to any one of the claims   1 to 4, characterized in that it further comprises: - means for closing (23; 31) of said tank (7), which is rotated by a first control cam (26), fixedly mounted on a shaft motor (27), between a closed position of said tank (7) and a position spaced from said tank (7), and - control means (28,29) of said reversing means (22,30), which comprises a second control cam (29) fixedly mounted on said shaft (27). 6. Device according to claim 5, characterized in that said closing means consists of a closure plate (23). 7. Device according to claim 5, characterized in that said closing means consists of a water tank (31) in which are arranged injectors (32) turned   towards said tray (7) ice maker.   8. Method for manufacturing ice cubes, comprising the steps consisting of: a) supplying water to a container (7) for shaping ice cubes, b) transforming said water into ice cubes (39) by passing a current through at least a Peltier thermoelectric module (16) whose cold face is in thermal contact with said tank (7), c) reversing the direction of current flow through said module (16), so as to demold said ice cubes (39 ), and d) recovering said ice cubes (39) thus removed from the mold, characterized in that it also consists in cooling, directly or indirectly, the hot face of said module (16), in freezing mode, by evaporation of a coolant generated by compression and condensation of a coolant. 30 9. Method according to claim 8, characterized in that said coolant is passed through a   evaporator (10; 15 ') in thermal contact with the hot face of said module (16).   10. Method according to claim 8, characterized in that it comprises the stages consisting: - in using said evaporation to freeze water in an ice bank (40), - in passing a cooling fluid over said bank ice (40), to cool said fluid, and - passing said cooling fluid thus cooled through a dissipator (15; 15 ') in contact   thermal with the hot face of said module (16). 11. Method according to any one of claims 8   to 10, characterized in that it further comprises the steps consisting: before step (a), of closing said tank (7) by a closing means (23; 31), and - before step (d ), to move said closing means (23; 31) from a closed position of said   tray (7) to a position spaced from said tray (7).