AU740132B2 - Ice slurry machine - Google Patents

Description

1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant/s: Actual Inventor/s: Clarke Refrigeration Limited Richard William CLARKE, Glenn Raymond MURRAY and Craig Richard CLARKE Address of Service: SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 "ICE SLURRY MACHINE" Invention Title: The following statement is a full description of this invention, including the best method of performing it known to us:- (File: 20540.00) 2 ICE SLURRY MACHINE This invention relates to an ice slurry machine and to a portable unit incorporating an ice slurry machine.

The quality of many foods deteriorates quite quickly if the food is not properly stored. This is particularly the case if the food is to be transported from its place of production or harvest, to market. In the case of fresh produce such as fruit and vegetables, it is generally necessary to transport the produce some distance from the place of harvesting to market. The produce must be kept cooled or chilled during transportation to ensure freshness and 10 produce quality are maintained. It is also important to remove or reduce the field heat from fresh produce, as this field heat can reduce the quality of the harvested produce.

i A number of cooling or chilling methods are currently in use. One is aircooling. Aircooling is not very energy efficient and results in the produce 15 being dried. Care must be taken that the produce does not become too dry.

Another method currently in use is hydrocooling. This involves the use of water to cool the harvested produce. In general terms, hydrocooling involves immersing the produce in a flow of chilled water, then packing the produce in an ice slurry in appropriate storage or transport containers. Hydrocooling avoids the problem of water loss from the produce which occurs with aircooling and is often more energy efficient.

Present methods of producing the ice slurry used in the hydrocooling technique are inefficient and time consuming. Such methods involve making 3 large blocks of ice in an ice making machine, transferring those blocks of ice to a tub of water and manually and mechanically breaking up the blocks of ice to form a slurry.

A need has been identified to provide a less labour intensive and more efficient means of producing an ice slurry.

Thus, it is an object of the present invention to provide an ice slurry machine which overcomes some or all of the abovementioned problems or which at least provides the public with a useful alternative.

It is a further object of the invention to provide a portable unit incorporating an ice slurry machine, which also provides the public with a useful alternative.

0o Other objects of the invention will become apparent from the following description.

I

According to one aspect of the present invention, there is provided an ice slurry machine comprising: a chamber having a water supply inlet and an ice slurry outlet, an ice removing means within the chamber and a refrigeration means associated with at least one internal surface of the chamber and adapted to chill that surface the arrangement being such that water or a water containing substance entering the chamber is chilled and forms ice at least in the proximity of the surface chilled by the refrigeration means, the ice on that surface being -4removed by ice removing means so that the ice mixes with the water or a water containing substance in the chamber to form a slurry which then flows out the outlet.

Preferably, the ice removing means is a movable blade.

Preferably, the movable blade extends from a rotatable shaft located centrally in the chamber.

Preferably, the movable blade is a helical blade.

Preferably, the refrigeration means comprises a refrigeration jacket which extends around the outer surface of the chamber.

o: 10 Preferably, the machine is provided with suitable support means.

According to a further aspect of the invention, there is provided a portable unit which includes an ice slurry machine as defined above.

S. According to a further aspect of the invention, there is provided a e method of producing an ice slurry, comprising the steps of: causing water or a water containing substance to flow over a chilled surface such that ice forms on that surface; removing the ice from the surface; and removing the mixture of ice with the residual water or a water containing substance.

Preferably, the chilled surface is a chamber.

Preferably, the ice is shaved in fine layers or chipped from the inner surface of the chamber. The shaved or chipped ice floats to the top of the chamber.

Preferably, excess water or the water containing substance is recycled for further use in the method.

The term water containing substance is intended to include fruit juices, alcoholic beverages, baking liquids, milk suspensions, body fluids, paint suspensions or emulsions, oil based emulsions or suspensions, aqueous 10 solvents, organic based solvents, saline solutions and the like.

loll Other aspects of the invention will become apparent from the following description, which is given by way of example only and with reference to the accompanying drawings, in which: S. Figure 1: shows a top view of an ice slurry machine according to the present invention; *i Figure 2: shows a side view of the machine shown in Figure 1; Figure 3: shows a side cross-sectional view of the machine shown in Figure 1; -6- Figure 4: shows a detailed side cross-sectional view of an ice slurry machine having helical supporting arms for the ice harvesting blades; Figure 5: shows a schematic side cross-sectional view of an ice slurry machine having lateral support arms for the ice harvesting blade; Figure 6: shows a plan view of the blade cutting angle of the embodiment illustrated in Figure Figure 7: shows a schematic view of a portable unit incorporating an ice slurry machine according to the present invention; 10 overall method of producing an ice slurry.

Figure 9: shows a schematic side-cross sectional view of an ice slurry machine of an alternative embodiment of the present invention; sooo of of o o Figure 10: shows a schematic side-cross sectional view of an ice slurry machine of a further embodiment of the present invention; Referring firstly to Figures 1 and 2, the invention provides an ice slurry machine 1, which comprises a substantially hollow chamber 2 defined by a cylindrical housing 3, a central rotatable shaft 4 extending along the length of the housing 2, and a refrigeration jacket 5 circumferentially surrounding the cylindrical housing 3 and extending along the length of the housing.

-7- Preferably, the machine 1 may be provided with suitable support means, for example feet 6 attached to the base of ice slurry machine 1.

Referring now to Figure 3, the machine 1 is also provided with at least one water or water containing substance inlet means 7 and at least one ice slurry outlet means 8. The rate of flow of the water or water containing substance into the chamber 2 depends on the nature of product required. If the product is to consist of substantially ice, a slow flow rate of water into the inlet and through the chamber may be necessary. If the final product is to consist of substantially chilled water a higher flow rate may be necessary.

The flow rate may vary from less than 0.1 I/min to greater than 10,000 I/min depending on the size of the chamber. The form of the final product, however, is also dependent on the degree of cooling to which the water or 0* water containing substance is subjected to in the chamber. The ice slurry ,i outlet means 8 is generally located at the top of the refrigeration jacket Extending outwardly from the central shaft 4 and into the chamber 2 is an ice harvesting blade 9. The blade 9 is preferably serrated and extends to a point g adjacent an inner wall of the housing 3. The blade may extend longitudinally :°:down the inner surface of the housing 3 or may be of a helical shape extending from the central shaft 4.

The refrigeration jacket 5 is provided with appropriate means for.

cooling, including at least one refrigerant liquid inlet line 10 and at least one refrigerant outlet suction line 11. The refrigerant inlet 10 is generally located at the base of the refrigeration jacket 5. The number of refrigerant inlet means may vary depending on the design and size of the ice slurry machine 1.

The refrigerant outlet line 11 is generally located at the top of the refrigeration 8 jacket 5. The number of outlets required may vary depending on the design and size of the ice slurry machine 1.

To provide a flow passage for refrigerant in the refrigeration jacket 5 a flat cross-section spiral (not shown) may be incorporated into the refrigeration jacket to aid in conveying the refrigerant. Alternatively, a coil or pipe system laced around the inner housing and inside the refrigeration jacket 5 may be employed. The width of the refrigeration jacket 5 may be of any design depending on the size of the ice slurry machine 1.

The ice slurry machine 1 is also provided with an appropriate power source (not shown). For example, it is envisaged that the machine 1 will usually be powered by electricity, in which case an appropriate electric plant is provided. It will be appreciated, however, that other suitable power sources e: may also be used.

i The operation of the machine 1 is now described, with particular 15 reference to Figure 3 of the accompanying drawings. When it is desired to b.

oo** produce an ice slurry, the refrigeration jacket 5 is operated, reducing the temperature of the housing 3 and the chamber 2 to an appropriate level.

Water or a water containing substance is then pumped into the chamber 2 via the water inlet means 7. Preferably, but not necessarily the water or water containing substance inlet means is positioned such that it provides the incoming water or water containing substance with a swirl component which is opposite in direction to the flow of the refrigerant through the refrigeration jacket 5. This arrangement ensures optimum heat transfer. As the chamber 2 fills, the water or water containing substance adjacent the inner surface of the -9housing 3 is cooled to a sufficiently low temperature so that ice forms on the surface. Some water or water containing substance will reach the top of the chamber 2 without turning into ice, however that water or water containing substance will be chilled.

During operation of the machine 1, the blade 9 rotates about the central shaft 4 in a direction indicated by arrow A. As it rotates, the blade 9 shaves or chips layers of ice from the surface of the chamber 2. The shaved or chipped ice is lighter than the chilled water or water containing substance, and it floats to the top of the chamber 2. At this point the ice and chilled water or water containing substance combine to form an ice slurry. The ice slurry is pumped out of the chamber 2 via the ice slurry outlet means 8, which is collected in a suitable manner (not shown). In one preferred form of the *4

,O

invention, the slurry may collect in a hose or nozzle arrangement which will allow an operator to apply it directly to produce being packed. Alternatively, the slurry may be pumped to a suitable container for later use.

a In one preferred form of the invention, the produce is packed in containers which have openings in the bottom. As the ice slurry is pumped over the produce, ice is trapped around the produce and the excess water or water containing substance is drained into an appropriate system for subsequent reuse in the slurry making process. In other words, the excess water or water containing substance is recycled.

As mentioned above, the blade 9 is preferably serrated. The serration pattern may be in any suitable form, and is designed to allow variations in pressure of the blade surface against the inner surface of the chamber 2, to 10 ensure the blade rotates smoothly and the ice is harvested in a constant manner. The profile of blade 9 can be varied to optimise the cutting angle.

The cutting edge may be straight, serrated or otherwise. It is also to be appreciated that a plurality of blades may be required to optimise the production requirements.

Preferably the clearance between the blades and the inside wall of the housing 3 is nominally 0.25mm.

However, the blades may be adjusted to meet various requirements for different applications.

•o o oo 10 With reference to Figure 4 a further embodiment of an ice slurry ~i "machine 1 is illustrated. The ice slurry machine may incorporate helical support arms 12 which are centrally located and attached to the central shaft 4. The helical support arms are attached to the blade and are employed to o: assist conveying the scraped ice from the inner surface of the housing 3 to the top of the chamber 2.

In an alternative embodiment and with reference to Figure 5, the ice harvesting blade 9 may be supported by lateral support arms 13. Figure 6 illustrates a plan view of the embodiment illustrated by Figure 5. Figure 6 illustrates one angle of the blade harvesting means relative to the inner surface of the housing 3.

It is envisaged that the rotating central shaft 4 is supported by bearings. With reference to Figures 4 and 5 the bearings 14 may be any type 11 of rolling contact bearing, sleeve bearing or such like to support the central shaft in both an axial and radial direction. The bearings will preferably be in a bearing housing 15 which is typically located concentrically to the housing 3 to provide uniform clearance between the blades 9 and the inside wall of the housing 3.

The rotational speed of the central shaft 4 is typically in the range of 3rpm. However, the speed of rotation is selected for each application. For example, the rotational speed of the central shaft can be varied to control the quality of ice produced.

oo Rotation of the central shaft is typically by way of a direct drive reduction gear-box and motor unit 16. However it is to be appreciated that any type of mechanism can be used to rotate the central shaft.

.0 0 0 0 el As described above a central auger may provide a mechanism for 0 e0 0 i assisting the conveying of ice through the ice slurry machine 1. It is envisaged that an auger or helical support arms 12 would be used especially .0 0 where the ice slurry machine is particularly large. For example the auger may 0 be attached to the central shaft 4 or to lateral support arms.

Referring now to figure 7, the present invention also provides for a portable unit 17 which incorporates an ice slurry machine 1. The portable unit 17 has application to field situations where produce is being cooled and packed at the place of harvesting.

12 In operation, the portable unit 17 would be used in the following way.

Freshly harvested produce is placed in containers on a chain conveyor 18 and moved in the direction indicated by arrow B. The produce firstly passes through a pre-wash area 19 where the produce is lightly washed to remove dirt, dust or extraneous matter. The produce is then moved on to a hydrocool area 20, which a standard hydrocooler removes the majority of field heat from the produce. In one preferred form of the invention, water used at this stage of processing is returned to a reservoir which is common to the ice slurry machine, thus reducing the amount of water used during the process as a whole.

From the hydrocool area 20, the produce is moved to a slurry area 21.

Here, the ice slurry machine 1 which produce ice slurry in the manner •o.

described above, is pumped or placed over the produce. As described above, containers for the produce preferably have spaces or openings in the bottom.

o o: 15 As the slurry is pumped over the produce, excess water will drain back into 0: 0.: 0 el the common reservoir and the ice will be trapped around the produce. As o excess water filters through the produce, further field heat will be removed.

•From the slurry area 21, the produce is moved to a final drainage area 22, to again minimise water loss. This also minimises bogging of ground at the exit to the unit 17, which might otherwise make working conditions difficult.

Thus, by this invention there is provided an ice slurry machine capable of producing an ice slurry suitable for use in the cooling and transporting of produce.

13 With reference to Figure 8 a flow diagram of the components of the preparation of an ice slurry is illustrated. The details of a refrigeration system is illustrated schematically in box 23. A compressor is shown as 24 and a thermostatic expansion valve is shown as 25. A water slurry tank is illustrated as 26. A water pump 27 is employed to pump the water into inlet 7.

With reference to Figure 9 a further embodiment of the present invention is illustrated. This embodiment has the drive and motor unit 16 located at the base of the ice slurry machine. This embodiment is open to the top and does not have an ice slurry outlet line. The top of the chamber 2 is g open to the surroundings allowing direct flow 28 outwards from the chamber.

This embodiment illustrates a helical blade 9. Such an embodiment may be employed in portable drinking systems for providing ice water.

S.The ice slurry machine of this embodiment may be submerged in the 0 15 water containing substance which is to be cooled. It is to be appreciated that if the ice slurry machine of figure 9 is submersed in the liquid which is to be cooled or chilled, the outer surface of the refrigeration jacket 29 may require insulation to prevent ice build up on the outer surface. However, in some applications it may be desirable to allow ice build up on the outer surface of the refrigeration jacket and therefore no insulation would be necessary. It is also envisaged that surface 30 may act to separate the lower portion of the ice slurry machine from the flow 28.

It is also envisaged that the centre of the chamber 2 may be refrigerated as illustrated in Figure 10 The refrigerated centre is shown as 14 31. To achieve this variation, almost every other component and layout of the ice slurry machine 1 would require variation. For example, a centreless variation of a helical auger 32 may be used to scrape the ice from the centre of the chamber, and the outer surface as illustrated. Further refrigerant inlet 33 and outlet 34 lines are required in this embodiment.

Other aspects of the invention will now be described.

The refrigeration system of the, machine 1 preferably, but not necessarily comprises two semi-hermetic compressors which can be run separately depending on the load requirements of the system. A heavy duty oooo10 vertical air flow condensor may be utilized, to dissipate refrigerant heat. Any e suitable refrigerant may be used. An example is R404A (HP62), which is an Sozone-friendly refrigerant. Because of the characteristics of R404A it is also possible for the housing defining a hollow chamber to be subjected to moderate to high pressure.

When using the portable unit 17 shown in Figure 7, it is envisaged that produce may have a temperature of approximately 18 0 C prior to processing and a temperature of approximately 4 0 C after processing. It is to be appreciated that any kilowatt rating of refrigeration may be employed to achieve such results.

It is envisaged that portable unit 17 may appropriately be powered by a diesel generator.

15 It should also be appreciated that the machine 1 of the invention may be operated at a temperature which allows it to produce chilled water or water containing substance rather than an ice slurry.

It is envisaged that the machine and portable unit of the present invention may be used in cooling or chilling produce such as sweet corn or other vegetables or fruit. However, it has equal application to chilling of other foods such as fish, or in the bread or pastry making process where an ice slurry may be used to slow fermentation. It is also envisaged that an ice slurry produced by machine 1 may be utilized in curing concrete.

10 It is also envisaged that by using a separating device, such as a sieve or the like, the slurry machine may be used to make standard shaved ice for general use or cooling purposes. For example, the ice slurry machine may be used to cool orange juice, milk, wine and various other slurry mixtures.

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o It is also envisaged that the ice may be shattered by way of *0 compressive forces exerted by the blade resulting in chipped ice. The S°harvesting blades may also peel ice from an inner surface resulting in ice S• flakes.

It is further envisaged that the ice slurry machine may be used to. chill water or a water containing substance. A storage tank may be incorporated into the slurry machine. The storage tank will hold cool water, which can be circulated. For example, the ice slurry mixture can be circulated for use as a secondary refrigerant, for cooling industrial machines, for air conditioning, milk cooling heat exchangers or the like.

16 A further advantage of the present invention is that the ice slurry machine may be used to make ice on a continuous basis to produce a storage of ice, such as an ice bank. A separating device may be used to remove the ice while the excess of water in the original slurry can be recirculated through the ice slurry machine by redirection to the water inlet.

A further advantage of the present invention is that the ice slurry machine may be employed to remove water from products such as wine or honey. The product is placed inside the vessel and the shaft is rotated to agitate the substance. The inside housing wall temperature is at for example, 10 -1.5 0 C and effectively freezes out the water from the product. The remaining ooo* e product can then be drained from the vessel. This process is dependent on o the properties of the product of the specific application.

The machine of the present invention may be formed of any suitable materials. It is envisaged that the cylindrical housing 3, refrigeration jacket 15 and blade 9 may be formed from plastics, stainless steel, titanium alloy, aluminium and carbon steel. For example, the inside chamber may be constructed from plate material rolled and welded into a cylinder, from seamless pipe or any other form of cylinder. If the chamber 2 is constructed from carbon steel or similar material, the inside surface of the chamber is preferably hard chromed for wear, corrosion resistance and for sanitation purposes. Accordingly, the inside surface of the chamber should be machined to a high finish to reduce the adhesion of the ice to the inside of the chamber surface. Furthermore, the inner surface of the chamber is preferably machined to produce a high quality surface finish, to ensure concentricity, roundness and uniform wall thickness.

17 Although the invention has been described by way of example and with reference to various embodiments thereof, it will be appreciated that variations and modifications may be made without departing from the scope of the invention. For example, it is envisaged that the ice slurry may be insulated to improve the performance of the machine, It is also envisaged that the ice slurry machine and chamber may be mounted horizontally rather than the upright position illustrated in the above embodiments.

It is further envisaged that as an alternative, a round coil or similar may be wrapped around the outside surface of the refrigerated jacket. By using a control system, water may be circulated through this coil to improve and enhance water cooling rates. It is envisaged that below a nominal temperature of 4 0 C water is not permitted to flow through the coil and the coil is drained of its contents to avoid freezing and ice build up accordingly.

el• p During ice production or when make-up water is required, the make-up water 15 for feeding back into the water inlet means may flow through this coil for preooio p p p cooling purposes.

°0 p° p pp

Claims (13)

1. An ice slurry machine comprising: a chamber having a water supply inlet and an ice slurry outlet, an ice removing means within the chamber and a refrigeration means associated with at least one internal surface of the chamber and adapted to chill that surface the arrangement being such that water for a water containing substance entering the chamber is chilled and forms ice at least in the proximity of the surface chilled by the refrigeration means, the ice on that surface being removed by ice removing means so that the ice S. mixes with the water or a water containing substance in the chamber 9999 to form a slurry which then flows out the outlet.

2. An ice slurry machine as claimed in claim 1, in which the ice removing means is a movable blade. S 15 3. An ice slurry machine as claimed in claim 2, in which the movable 9 blade extends from a rotatable shaft located centrally in the chamber.

4. An ice slurry machine as claimed in claim 3, in which the removable blade is helical blade or auger. An ice slurry machine as claimed in any one of claims 1-4, in which the refrigeration means is a refrigeration jacket which extends substantially around the outer surface of the chamber. 19

6. An ice slurry machine as claimed in any one of claims 1-5, in which the machine is provided with suitable support means.

7. An ice slurry machine as claimed in any one of claims 1-6, in which the ice slurry machine itself is in a portable unit.

8. A method of producing an ice slurry, comprising the steps of: causing water or a water containing substance to flow over a chilled surface such that ice forms on that surface; removing the ice from the surface; and removing the mixture of ice with the residual water or a water o*e 10 containing substance.

9. A method of producing an ice slurry as claimed in claim 8, in which the chilled surface is a chamber. o@ o

10. A method of producing an ice slurry, as claimed in claim 9, in which the ice is shaved in fine layers or chipped from a surface of the .i 15 chamber.

11. A method of producing an ice slurry, as claimed in claim 10, in which the shaved or chipped ice floats to the top of the chamber, or is promoted to the top of the chamber by a conveying means.

12. A method as claimed in claim 11, in which the conveying means is a helical auger. 20

13. A method as claimed in any one of claims 8-12, in which the excess water or a water containing substance from the ice slurry is recirculated for further use in the method according to any one claims 8-12.

14. An ice slurry machine, substantially as herein described with reference to any one of Figures 1-3. An ice slurry machine, substantially as herein described and with reference to any one of figures 4-7, 9 and

16. A method of producing an ice slurry, substantially as herein described and with reference to Figure 8. DATED this 9th day of February 1998. CLARKE REFRIGERATION LIMITED Attorney: RUSSELL J. DAVIES Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS oo *o o* *oo o