DE102011089868A1 - Apparatus and method for producing ice-cream - Google Patents

Abstract

The invention relates to an apparatus and a method for producing Eisbrei in a refrigerant mixture (6), wherein by means of a fluid supply means (7), a fluid to the brine mixture (6) discontinuously for an ice crystal formation and / or Eiskristallablösung can be supplied.

Description

The invention relates to an apparatus and a method for producing ice pulp.

As "ice slurry" or pumpable ice is referred to in the context of the invention, a biphasic mixture comprising ice particles and a liquid refrigerant. The ice particles typically have a size or a diameter of about 0.01 mm to about 0.5 mm, with a low concentration of the additive and particle sizes of about 1 mm are possible. As a liquid refrigerant, water is usually used, to which an additive is added to lower a freezing point, for example, salt, especially sodium chloride (NaCl), and / or a hydrocarbon-oxygen compound, especially ethanol and / or glycol. In connection with the application, a mixture of water and an additive or another refrigerant with or without additive is referred to as a refrigerant mixture.

For the formation of ice particles or ice crystals usually heat exchangers are used, with ice crystals form in the form of ice sheets on surfaces of the heat exchanger. The ice sheets formed have a significantly larger surface area than desired for ice particles. To generate the ice particles, it is therefore known to crush the ice sheets by defrosting or by mechanical means or to avoid the growth of larger ice sheets.

For example, is for the production of Eisbrei WO 2009/034300 A1 known to provide heat exchanger plates, which are traversed by a cooling liquid, wherein deposited on an outer surface of the heat exchanger plate ice. The depositing ice falls, for example due to gravity in a arranged below the heat exchanger plates container. In addition, the heat transfer plates can be temporarily heated to blow off the accumulating ice.

From the EP 0 705 413 B1 a device for producing Eisbrei with a heat transfer tube is known, wherein a refrigerant over an outer side of the heat transfer tube and the liquid to be cooled are passed over an inner side of the heat transfer tube. For detachment of an ice layer depositing on the inside, a spinner or whip rod is arranged in the heat transfer tube, which circulates along an inner surface of the heat transfer tube and separates the ice layer. The falling ice layer is collected in a container.

It is an object of the present invention to provide an apparatus and method for making ice-cream which allows for the production of ice-cream with low wear on components and long service intervals.

This object is solved by the objects with the features of claims 1 and 8. Further advantages of the invention will become apparent from the dependent claims.

According to a first aspect, an apparatus for producing ice slurry in a brine mixture is provided, comprising at least one outlet opening, via which a fluid can be fed to the brine mixture, wherein a fluid supply means is provided, by means of which the fluid to the brine mixture over the at least one outlet opening discontinuous for an ice crystal formation and / or a Eiskristallablösung can be fed.

An ice crystal formation takes place at so-called nucleation sites, wherein attached to the nucleating the freezing broth mixture to be frozen. The discontinuously supplied fluid causes ice crystal formation and / or ice crystal separation. As the fluid, a suitable gaseous or liquid medium, in particular air, can be used.

In the context of the application, a discontinuous supply of a fluid is termed a time-variable supply of a fluid, wherein a volume, a pressure and / or another parameter of a fluid flow of the supplied fluid varies and / or a fluid flow is temporarily interrupted.

A discontinuous feed takes place in one embodiment in such a way that the fluid can be introduced into the coolant mixture at least partially in the form of fluid particles, such as drops or bubbles, the fluid particles serving as a nucleation site for ice crystal formation. As the fluid, for example, air is used, which can form air bubbles in an air supply, which can then serve as a germination site.

Alternatively or additionally, in one embodiment, a heat transfer element is provided with a free surface contacting the brine mixture for ice crystal formation, wherein at least one irregularity preferably serves as nucleation site for ice crystal formation on the surface. As a heat transfer element in connection with the application, a suitably designed component is designated, on the surface of which there is an ice crystal formation. The discontinuously supplied fluid serves one Eiskristallablösung. For this purpose, in one embodiment, a discontinuous fluid flow of the supplied fluid is directed towards the surface, whereby detachment occurs due to the kinetic energy of the fluid. Preferably, the surface has at least one irregularity which serves as a nucleation site. As a result, a place of origin of the formation of ice crystals is localized, so that the fluid flow can be targeted to the forming ice crystal.

In an advantageous embodiment, the at least one outlet opening opens on the free surface, so that the at least one outlet opening forms an irregularity for an ice crystal formation. This makes a simple design possible. In one embodiment, the heat transfer element is made of a porous material, wherein pores arranged on the surface form outlet openings in the sense of registration and the fluid can escape from the pores over the entire surface. In one embodiment, the heat transfer element is made of a sintered material for this purpose. In other embodiments, the heat transfer element is made of a fluid-tight or substantially fluid-tight material and has at least one inlet for connection to the fluid supply device, which is communicated via at least one fluid channel with the at least one outlet opening. In one embodiment, a plurality of heat exchanger elements are provided, which each have a fluid channel and at least one outlet opening. In advantageous embodiments, a heat exchanger element is provided with a plurality of outlet openings which open on the free surface. The outlet openings are suitable in shape and / or size, for example, with an angular cross-section or with an oval cross-section shapable. The outlet openings are suitably distributed over the surface and connected to at least one, preferably with a plurality, in particular with a plurality, parallel fluid channels with the fluid supply device or with a plurality of fluid supply means.

The fluid supply device is designed in one embodiment such that a supplied fluid flow is temporarily interrupted. During an interruption of the fluid flow, an ice crystal may form at the at least one outlet opening and / or another irregularity. By re-supplying a fluid stream, the ice crystal is dissolved. In this case, provisions are preferably made to prevent the refrigerant mixture from entering the fluid passage and / or a porous surface connected to the at least one outlet opening during the interruption of the fluid flow. For this purpose, semipermeable membranes are provided in one embodiment.

In advantageous embodiments, the fluid at the at least one outlet opening can be acted upon by means of the fluid supply device with a variable, in particular a pulsating pressure. A pressurization takes place in such a way that a pressure between a low pressure level and a high pressure level is varied. In advantageous embodiments, a high pressure level is applied only for a short time, in particular pulse-like. The low pressure level is selected in advantageous embodiments so that a quasi-static state is taken, wherein the low pressure level is sufficiently high to prevent penetration of the refrigerant mixture into the fluid channel or the fluid channels, but is chosen so low that a Supply of the fluid to the brine mixture via the outlet opening is also interrupted or at least substantially interrupted. In this condition, i. when applying a pressure with a low pressure level, an ice crystal may form at the at least one outlet opening and / or another point of the heat transfer element, in particular an irregularity. The ice crystal is dissolved by applying a high pressure level due to the kinetic energy. For this purpose, in one embodiment, a pressure pulse is applied. The duration of time between two pressure pulses or two periods to which a high pressure level is applied determines the size of the resulting ice crystals. The time period is therefore also referred to as the growth period. The growth time is to be long enough to form ice crystals whose size exceeds a critical radius, so that an immediate dissolution of the ice particles in the ice slurry is prevented. By a pressure pulse, it is also possible to introduce the fluid at least partially in the form of fluid particles in the brine mixture, wherein the fluid particles additionally or alternatively serve as a nucleation site for an ice crystal formation. The variation of the pressure can be realized by suitable means which are provided on a fluid source, on the at least one outlet opening and / or on the at least one fluid channel. Preferably, the variation takes place at the fluid source, so that mechanical wear parts in the region of the heat transfer element can be completely dispensed with.

In one embodiment, the heat transfer element is additionally cooled by suitable means, for example a refrigerant conducted through additional channels. In other embodiments, the fluid is passed through the heat transfer element and serves to cool it.

In a further embodiment, by means of the fluid supply means, the fluid with a fixable fluid temperature fed to the refrigerant mixture. Using the fluid for ice crystal separation, the heat energy of the supplied fluid passes into the ice crystal detached by the fluid. The fluid temperature is therefore preferably matched to the brine mixture and in particular chosen so that it is not significantly higher than the freezing point of the brine mixture. This prevents that the phase change is reversed by the heat energy of the fluid. The low fluid temperature also supports the use of the fluid particles as a germinal point. In advantageous embodiments, the fluid temperature exceeds a freezing point of the brine mixture by a maximum of 30 K, in particular by a maximum of 20 K, more preferably by a maximum of 5 K. In some embodiments, the fluid temperature is below the freezing point of the brine mixture. In other embodiments, it is in the range or above freezing.

In further embodiments, a collecting container filled with a brine mixture and / or a channel through which a refrigerant mixture flows are provided, wherein the fluid is discontinuously mixed with the brine mixture in the collecting container and / or in the channel for ice crystal formation and / or by means of the fluid supply device Ice crystal separation can be fed.

According to a second aspect, there is provided a method for producing ice slurry in a brine mixture, wherein a fluid is supplied to the brine mixture discontinuously for ice crystal formation and / or ice crystal separation.

For example, a device having at least one outlet opening is provided for supplying the fluid, wherein the outlet opening and / or the fluid emerging from the at least one outlet opening preferably serve as nucleation site for ice crystal formation.

The fluid supplied to the brine mixture is applied in an advantageous embodiment with a variable, in particular a pulsating pressure. By a fluid flow at a high pressure level while a kinetic energy is supplied to the brine mixture for ice crystal separation. High pressure fluid particles can also act as nucleation sites for ice crystal formation. In particular, it is also useful that there is a cooling of the fluid particles in a relaxation under a prevailing in the refrigerant mixture atmospheric pressure. Alternatively or additionally, the fluid is supplied to the brine mixture with a definable fluid temperature, wherein preferably the fluid temperature exceeds a freezing point of the brine mixture by a maximum of 30 K, in particular by a maximum of 20 K, more preferably by a maximum of 5 K. In some embodiments, the Fluid temperature below freezing.

Further advantages of the invention will become apparent from the subclaims and from the following description of embodiments of the invention, which are shown schematically in the drawings. For identical or similar components, the same reference numbers are used in the drawings. Features described or illustrated as part of one embodiment may also be used in another embodiment to obtain a further embodiment of the invention.

In the drawings show:

1 a first embodiment of a heat transfer element for apparatus for producing Eisbrei in a refrigerant mixture;

2 a second embodiment of a heat transfer element similar 1 ;

3 a first embodiment of an apparatus for producing Eisbrei in a refrigerant mixture comprising a heat transfer element according to 1 or 2 and

4 A second exemplary embodiment of a device for producing ice slurry in a coolant mixture comprising a heat transfer element according to FIG 1 or 2 ,

1 and 2 each show schematically a heat transfer element 1 for example, in the 3 and 4 illustrated device 4 for producing ice slurry in a brine mixture. In use, the heat transfer element 1 For example, arranged as a heat exchanger so that it connects a refrigerant circuit and a Eisbreikreislauf together. As the refrigerant circuit while a circuit for an inserted refrigerant is referred to, wherein the heat transfer element 1 acts as an evaporator for the refrigerant. In the second cycle, the Eisbreikreislauf, acts the heat transfer element 1 as Eisbreierzeuger for the production of Eisbrei in the refrigerant mixture.

The in the 1 and 2 shown heat exchanger elements 1 each have a substantially cuboid shape with a free surface 10 on. In other embodiments, other designs are conceivable. The illustrated heat exchanger elements 1 each comprise a plurality of outlet openings 2 , which on the surface 10 lead. The outlet openings 2 are shown only schematically and greatly enlarged.

This in 1 illustrated heat transfer element 1 has several, in the illustrated embodiment six, arranged in a row outlet openings 2 on, which has a non-visible, inside the heat transfer element 1 arranged fluid channel with an inlet 3 are communicated.

The heat transfer element 1 according to 2 has a plurality of outlet openings arranged in rows 2 each having a row of outlet openings via an associated fluid channel having an inlet 3 is communicated.

At the inlet 3 ( 1 ) or the inlets 3 ( 2 ) is at least one fluid supply device connectable, wherein a plurality of inlets 3 according to 2 can be connected to a common fluid supply device. In other embodiments is for each inlet 3 according to 2 a separate fluid supply device provided.

By means of in the 1 and 2 illustrated heat transfer element 1 and one in 1 and 2 Fluid supply device, not shown, a fluid can be fed to a brine mixture discontinuously for an ice crystal formation and / or a Eiskristallablösung. Air is preferably used as the fluid. The fluid, in particular the air, occurs discontinuously over the outlet openings 2 out. The outlet openings 2 and / or the exiting air, in particular in the form of air bubbles, serve as nucleation site for an ice crystal formation.

The 3 and 4 each show very schematic sectional views of a device 4 comprising a heat transfer element 1 with outlet openings 2 according to 1 or 2 , where the outlet openings 2 each via a fluid channel 20 with a fluid supply device 7 are connected.

In the 3 illustrated device 4 includes a collection container 5 , which with a brine mixture 6 is filled. The heat transfer element 1 is so in the sump 5 arranged that a surface of the heat transfer element 1 at which the outlet openings 2 open, the brine mixture 6 is facing. By means of the fluid supply device 7 is a fluid of the brine mixture 6 over the outlet openings 2 discontinuously fed for an ice crystal formation and / or a Eiskristallablösung. Due to a lower density of the ice particles compared to the brine mixture 6 detached ice particles rise in the sump 5 up.

In the embodiment according to 4 is a channel 8th or a pipe provided, which of a refrigerant mixture 6 is flowed through. In the channel 8th is a heat transfer element 1 arranged, wherein a surface of the heat transfer element 1 at which the outlet openings 2 open, the brine mixture 6 is facing. Next is also a fluid supply device 7 provided by means of a fluid to the brine mixture 6 over the outlet openings 2 discontinuously be fed for an ice crystal formation and / or a Eiskristallablösung.

In the illustrated embodiment, a pressure level of the fluid, in particular the air, at the outlet openings 2 by means of the fluid supply device 7 varies between a low pressure level and a high pressure level. The low pressure level is sufficiently high that penetration of the brine mixture 6 over the outlet openings 2 in the fluid channels 20 is prevented. At the same time, the low pressure level is chosen low enough that through the outlet openings 2 when concerns the low pressure level no or only a very minor supply of fluid to the brine mixture 6 he follows. While the low pressure level is applied, thereby serve the outlet openings 2 according to the 1 and 2 as nucleation sites for ice crystal formation. One at the outlet openings 2 forming ice crystal is released by increasing the pressure level again. In this case, the high pressure level is preferably applied in the form of a pressure pulse. By varying the time interval between two pressure pulses, a crystal growth time can be varied. When the high pressure level is applied, an entry of fluid particles, in particular of air bubbles, into the coolant mixture may occur. These fluid particles can also serve as a nucleation site for ice crystal formation.

A fluid temperature of the over the outlet openings 2 supplied fluid is not selected significantly higher in the illustrated embodiment, as the freezing point of the in the collecting container 5 or the channel 8th existing refrigerant mixture. This prevents that a heat energy of the supplied fluid, which enters the ice crystal upon detachment of an ice crystal, does not reverse the phase change of the brine mixture.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2009/034300 A1 [0004]
• EP 0705413 B1 [0005]

Claims (10)

Device for producing ice-cream in a mixture of refrigerants ( 6 ) with at least one outlet opening ( 2 ), via which a fluid to the brine mixture ( 6 ), characterized in that a fluid supply device ( 7 ) is provided, by means of which the fluid to the brine mixture ( 6 ) via the at least one outlet opening ( 2 ) is discontinuously fed for an ice crystal formation and / or a Eiskristallablösung. Apparatus according to claim 1, characterized in that by means of the fluid supply means ( 7 ) the fluid at least partially in the form of fluid particles in the brine mixture ( 6 ), wherein the fluid particles serve as nucleation site for an ice crystal formation. Apparatus according to claim 1 or 2, characterized in that a heat transfer element ( 1 ) with a refrigerant mixture ( 6 ) contacting surface ( 10 ) is provided for an ice crystal formation, wherein preferably at the surface ( 10 ) is provided at least one irregularity as a germination site for an ice crystal formation. Apparatus according to claim 3, characterized in that the at least one outlet opening ( 2 ) on the surface ( 10 ), so that the at least one outlet opening ( 2 ) serves as a nucleation site for ice crystal formation. Device according to one of claims 1 to 4, characterized in that by means of the fluid supply means ( 7 ) the fluid at the at least one outlet opening ( 2 ) With a variable, in particular a pulsating pressure can be acted upon. Device according to one of claims 1 to 5, characterized in that by means of the fluid supply means, the fluid having a definable fluid temperature of the brine mixture ( 6 ), wherein preferably the fluid temperature exceeds a freezing point of the brine mixture by a maximum of 30 K, in particular by a maximum of 20 K, more preferably by a maximum of 5 K. Device according to one of claims 1 to 5, characterized in that a with refrigerant mixture ( 6 ) filled collecting container ( 5 ) and / or a mixture of refrigerants ( 6 ) channel ( 8th ) is provided, wherein by means of the fluid supply means ( 7 ) the fluid to the brine mixture ( 6 ) is discontinuously fed for an ice crystal formation and / or a Eiskristallablösung. Process for the production of ice-cream in a mixture of refrigerants ( 6 ), characterized in that a fluid is the refrigerant mixture ( 6 ) is fed discontinuously for ice crystal formation and / or ice crystal separation. A method according to claim 8, characterized in that the the brine mixture ( 6 ) supplied with a variable fluid, in particular a pulsating pressure is applied. A method according to claim 8 or 9, characterized in that the fluid to the brine mixture ( 6 ) is supplied with a definable fluid temperature, wherein preferably the fluid temperature exceeds a freezing point of the brine mixture by a maximum of 30 K, in particular by a maximum of 20 K, more preferably by a maximum of 5 K.

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