GB2226874A

GB2226874A - Ice-maker

Info

Publication number: GB2226874A
Application number: GB9002027A
Authority: GB
Inventors: John James Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-04-04
Filing date: 1990-01-29
Publication date: 1990-07-11
Also published as: GB2189016B; GB2189016A; GB9002027D0; GB8708027D0

Description

1 j is ICE MAKER The invention relates to ice makers (ie apparatus f or

freezing water to form blocks of ice). The invention is particularly but not exclusively concerned with ice makers in which production of ice formations of a desired size (including completion of a freezing cycle) is detected by indirect means rather than by obstruction to the movement of such means as a paddle in a body of water contained by the ice maker.

Ice is very commonly used in keeping food such as butter cool after serving and, more importantly, forcooling f ish (such as on display at point of sale) and drinks ( such as beverages) either by contact with a bottle or like container containing the drink or by addition of ice pieces to the drink itself. Apparatus for producing such ice in chunk or piece form are therefore in great demand both for domestic use and to a greater extent for use in service establishments such as restaurants, bars and hotels.

Ice can, of course, be produced by freezing relatively large bodies of water to form blocks of such size that disintegration by mechanical means such as hammering is practical to produce chunks or pieces of sizes suitable for the use intended (eg addition to a glass or beverage). This method is, however, inefficient and inconvenient. A large body of water tends to insulate itself so that internal regions remain unfrozen for 1 11 (; considerable time giving rise to delay and excessive energy requirements. A large ice block is also difficult and labour-intensive to disintegrate manually and disintegration is messy and results in chunks undesirably varied in size and shape. Voltage cutting grids avoid these problems to some extent but still represents an inconvenient second stage in an overall inefficient procedure and, of course, adds to equipment and energy costs.

Ice is accordingly made primarily in apparatus which freezes water so as directly to form chunks or pieces of desired shape and size, both being generally uniform as between one piece and another.

One apparatus of this kind comprises a vessel equipped with controlled water-supply means. The vessel has an open top through which an evaporator assembly connected to a refrigerant supply extends. The evaporator comprises a plurality of downwardly extending finger-like elongate members each supplied with refrigerant and extending in use into a body of water contained in the vessel. Water in contact with fingers freezes on finger surfaces forming a shell of ice with the finger forming a core of an otherwise hollow ice formation. A paddle sweeping through the water surface snags on the ice formations when they reach a predetermined size and thereby activates a microswitch causing motors to lower the vessel, so that the fingers are withdrawn from the 1 water in the vessel, and displces the vessel laterally. Hot gas is then supplied through the refrigerant supply system in a reverse refrigeration cycle so that the icefinger interfaces are broken allowing the ice formation to fall from the fingers into a receptacle. Thereafter, the evaporator and paddle is placed back into water in the vessel and the cycle repeated. In order to throw the microswitch, the paddle must come to an abrupt halt and for this purpose, it is rotated fairly quickly, typically at a speed of about 60rpm.

Apart from the requirements of ice makers already specified above and the need for production speed, it is highly desirable to be able to produce ice formations which have a high level of optical clarity since clear ice is considered desirable, particularly for use in cooling beverages such as alcoholic drinks. It has been found that formation of high clarity ice is assisted by ensuring that the body of water in which an evaporator operates is kept dynamic rather than still. A paddle such as in the ice making apparatus referred to above may enable ice clarity to be achieved. However, in that apparatus, the paddle is operative continuously and at a fast rate. The use of paddles for the above purpose thus is known but has not been used effectively in the context of finger-type evaporator ice makers.

According to the invention, apparatus for production of ice pieces comprises a reservoir for containing a body of water, an evaporator for effecting freezing of water, said evaporator including at least one freezing member (eg an elongate member in the f orm, f or example, of a right circular cylindrical-member) and being coupled to a refrigerant supply for performing a freezing cycle and a defrost medium supply for performing a defrost cycle, and means f or agitating the body of water so that the ice formed by the evaporator is clear, the freezing member(s) of the evaporator in operation of the apparatus f orming an ice f ormation over its surface and being so oriented that the formation, on release from the member by the defrost cycle, seperates from the member as a single piece and by its buoyancy elevates to the surface of the body of water for harvesting.

In a second aspect, the invention includes within its scope a method of producing ice which method comprises operating a freezing cycle with respect to apparatus as just defined above whilst disturbing or agitating the surface of the water, for example with a paddle conveniently operating at a speed of rotation such that a paddle blade penetrates the water surface at a rate of less than 15 times per minute (eg 10 times or less per minute). Penetration will be by a small amount in general, eg less than 25mm and more than 5mm (eg 15mm). The freezing cycle is followed by a reverse refrigeration cycle or other method of effecting removal and flotation of formed ice, during which the paddle may be stopped.

The evaporator will conveniently comprise a plurality of freezing members, numbering for example four or more.

A-plurality of members may be used. For example, several evaporators of eg five freezing members each, may be juxtaposed in the reservoir.

The elongate freezing members will generally take the form of vertical fingers but it is possible to provide members"which deviate from verticality without preventing upward flotation of ice pieces to the water surface for harvesting.

Water agitation may be achieved by a variety of means.

Preferably, however, agitation is effected by means of a driven paddle disposed to penetrate the water surface by rotation of one or more blades thereof (usually a single blade) and in so doing also harvest the floating ice pieces by conveying them to an extremity of the reservoir and into a receptacle. An electrically driven paddle is most convenient. The paddle will typically rotate at a slow speed of less than 15rpm, preferably not more than 1Orpm.

For ease of manufacture, the evaporator (or evaporators) is disposed in the reservoir without penetrating its walls. A perforated wall vessel received in the reservoir has the evaporator freezing members received through its wall (eg base) and secured in place by means 1 such as brazing or soldering in the case of an evaporator made of copper or copper alloy. The vessel serves to confine floating ice pieces to a region where a paddle or other means of water agitation can operate without restriction by refrigerant supply/defrost medium lines feeding the evaporator. Whilst this can be avoided in the alternative by perforating the reservoir walls, this leads to greater manufacturing problems, particularly due to the need to provide reliable sealing of the reservoir at the points of penetration.

In a particular embodiment of the invention, an ice making apparatus comprises a first open-topped vessel for containing a body of water in water-tight fashion, a second open-topped vessel disposed within the first and communicating therewith so as to receive water therefrom in use, at least one evaporator disposed with upright elongate freezing members thereof received through a base of the second vessel, lines for supply of refrigerant or defrost medium (eg hot gas) to said freezing members, said lines coupling to the evaporator without penetrating the open top of the second vessel, water supply means for supply of water to the first vessel of the apparatus and means for agitating the water surface within the open top of the second vessel and to sweep floating ice formations to and past an extremity of the second vessel.

The following is a specific description intended to il.Lustrate an embodiment of the invention, by way of k r example only, refernce being made to the accompanying drawings in which:- Figure 1 shows the apparatus in perspective view; Figure 2 is a different view of the apparatus of Figure 1 showing components not shown in Figure 1 but with other components omitted in the interests of slimplicity; Figure 3 shows part of the apparatus of Figure 1 in more detail and on a slightly enlarged scale; and Figure 4 is a block diagram showing a refrigeration system incorparating the invention, one refrigerant circuit being shown in solid lines and an alternative form which the circuit may take being shown in dotted 1 ines.

The ice making apparatus shown in the drawings comprises a copper, stainless steel or plastics water-tight vessel 1 having an open top 2. A second copper or stainless steel vessel 3 is disposed within vessel 1 and has an open top 4.

Four evaporators (one only shown) shown generally at 5 are disposed side-by-side in series within vessel 1.

Each has a tubular upright fingers 7.

base 6 coupling in series five The fingers 7 are received through the base of vessel 3, perforations (Figure 2) being provided therein for this purpose. Spot b:azing (not 1 X -.

--0- shown) secures the base 6 to the outer surface of the base of vessel 3. Copper supply lines 8 and 9 respectively provide for refrigerant and hot gas supply as shown in Figure 4 also, to the fingers 7 in freezing and def rost cycles, respectively according to the state of a contral switch serving for commutation, line 8 being a capillary copper line whilst line 9 is copper line of 3.175mm inside diameter. Suction line 10 of 6.35mm inside diameter copper tubing couples to an opposed end of the series of fingers to the two supply lines 8 and 9 and connect its respective evaporator in series to the next or to a compressor (not shown). All three lines pass through the open top 2 of vessel 1 in the space between the wall of vessel 1 and that of vessel 3 whereby the water surface confined by the open top of vessel 3 is not interrupted.

A shallow ridge or similar member (not shown) may be provided on the underside of the base of vessel 3 so that it sits stably and horizontally having regard to the thickness of tubular base 6 disposed between the two vessels.

Paddle 11 has blade 12 and is driven in rotation on shaft 13 by electrical power means (not shown), blade 12 penetrating the water surface in use.

Ball valve 14 perforates the side wall of vessel 1 (Figure 2) and comprises a float 15, a cantilever support arm 16 and an inlet orifice (not shown) for water entry.

C -g- In use, water supply enters vessel 1 via ball valve 14 and enters vessel 3 through the finger-receiving perforations previously referred to. When adequate water is present, ball valve 14 ceases further supply. A refrigeration cycle is commenced by supply of refrigerant to evaporator 5 via line 8 from a remote compressor (not shown). At the same time, paddle 11 is operated so that its blades 12 agitate the water surface and upper regions of the body of water thus producing water f low also in the region of fingers 5. The rate of water penetration by blade 12 is slow, typically around 8 penetrations per minute, in order to remove air ef f iciently and enhance ice clarity. Ice formations form on each of the fingers 7 as shown in Figure 3. After a time predetermined as adequate to produce ice formations of adequate size, the refrigeration cycle is reversed (ie hot gas defrost medium is supplied to fingers 7 via line 9). The increased surface temperature of fingers 7 releases the ice formations from the fingers, the released ice formations floating to the surface of the body of water by virtue of their own buoyancy. Blades 12 of paddle 11 convey the ice formations to the common edge of vessels 1 and 3 and, after a build-up of ice pieces, the ice pieces fall over the edge into a receptacle (not shown). Upon separation of ice formations from fingers 7 (the duration of the defrost cycle being predetermined to achieve this), a further freezing cycle is commenced to produce further ice. The two cycles continue in alternation continuously or until a Oesired level of ice production j k_ is achieved.

The duration of the freezing and reverse refrigeration cycles referred to and commutation between them may be controlled by an electronic timer (not shown) calibrated for particular use conditions so as to produce ice formations of a predetermined size and to effect their removal into the body of water. Such control is, however, preferably effected on the basis of temperature sensing as illustrated in Figure 4. Thus, a variable resitance temperature sensitive probe of a kind well known in the art (not shown) is conveniently disposed in the flow path of suction line 10 or attached to its outer surface (in either case at a location upstream from the compressor) for sensing the temperature of refrigerant in the line. The sensor probe may be calibrated so as to signal at 20OF to a solenoid control valve or switch to cease the freezing cycle and commence the defrost cycle, the control valve serving as the commutation means referred to earlier for commutation between freezing and defrost. Such control valve and its operation are wellknown in the art. Calibration of the probe is conveniently such that the control valve is actuated to commence a fresh freeze cycle (and to cease the defrost -.cycle) at a threshold temperature of 400F.

As will be appreciated from Figure 4, the temperature sensor senses temperature in line 10 and at the upper threshold closes the solenoid valve or switch. In this condition, pressurized refrigerant issuing from the compressor is directed to the condenser via line 9 to the evaporator 5. As ice forms on fingers 7, the temperature of refrigerant issuing to line 10 decreases (as less heat is absorbed from the body of water in the vessel 3). When the 20OF lower threshold temperature is reached, the sensor responds with an electrical signal causing the solenoid valve to open. This opens a path of smaller resistance than that via the condenser with the result that refrigerant in line 10 (or from the compressor) passes as hot gas via the open solenoid valve to the evaporator 5 rather than through the condenser. The heat contained in the hot gas is given up to the evaporator (rather than the condenser) to effect release of ice formations from the fingers 7. The signal from the sensor to open the valve may also stop a fan (not shown) normally operating to dissipate heat from the condenser. Further commutation to a freeze cycle takes place when the temperature in line 10 has increased to 400F.

The apparatus shown was found to produce very clear ice speedily and efficiently. At working environment and supply water temperatures of 500 and 600F, respectively, it was found the 1.51bs approximately of ice pieces could be produced per hour (measured on a slightly modified apparatus having only fifteen fingers). If the paddle was not operated or operated at a conventional speed of about 60 rpm during freezing cycles, there was serious loss of ice clarity.

The invention as described without reference to the drawings may include any one or more features of the invention as described with reference to the drawings.

is Included within the scope of the invention is ice-making apparatus of any of the forms defined herein in combination with an electrical control system operative to switch the cycle of the refrigeration between freezing and release after a desired time (eg by temperature sensing). Refrigerant and defrost media are thus run through the evaporator from sources not forming part of the apparatus itself in alternation according to a preset pattern, refrigeration cycles commencing once the ice formations separate from the fingers (or other freezing members), preferably assisted by their buoyancy, in the body of water in which the fingers are immersed. It will thus be appreciated that in all its forms the invention does not necessarily rely on the prior art principle of physically detecting the presence of an ice formation of a certain threshold size by its obstruction of a mechanical movement of an apparatus component such as a driven paddle. Rather, the invention, in its preferred embodiments at least, utilizes the paddle for ice clarity achievement only (whereby it can be driven at optimum slow speed) and achieves cycle commutation by other means.

1

Claims

1. An apparatus f or the production of ice pieces which apparatus comprises a reservoir f or containing a body cI water, an evaporator for effecting freezing of water, said evaporator including at least one freezing member disposed for immersion in said body of water and the evaporator being arranged for supply of refrigerant thereto from a source thereof for performing a freezing cycle; agitation means for agitating the body of water so, that ice formed by the evaporator is clear, termination means for terminating the freezing cycle when the.

freezing cycle is complete and a desired extent of ice formation has taken place and means for determining when the said desired extent of ice formation has taken place (eg by detecting a parameter representative there of, other than a dimension thereof).

2. An apparatus as claimed in Claim 1 which includes commutation means for alternating between the freezing cycle and a def rost cycle in which a def rost medium is supplied to a freezing member to effect release of ice formation thereon.

3. An apparatus as claimed in Claim 1 or Claim 2 wherein the agitation means comprises a paddle which operates to disturb the surface of the body of water.

4. An apparatus as claimed in any on of Claims 1 to 3 wherein the means for determining ice formation of a c predetermined desired extent comprises timer means calibrated to actuate said termination means after a time lapse predeteremined as representive of the predetermined desired extent of ice formation.

5. An apparatus as claimed in any one of Claims 1 to 3 wherein the means for determining when the said desired extent of ice formation has taken place comprises temperature sensing means preferably sensing the temperature of the refrigerant.

6. An apparatus as claimed in Claim 5 wherein the temperature sensing means is disposed to sense the temperature of the refrigerant in a refrigerant line for flow of refrigerant from said evaporator.

7.. An apparatus as claimed in claim 6 wherein the refrigerant line is a suction line defining a downstream - directed flow path from a freezing member to a compressor.

8. An apparatus as claimed in any one of Claims 5 to 7 wherein the temperature sensing means is calibrated to actuate means to cease the freezing cycle at a threshold temperature of from 150 to 300 (eg 150 to 250).

9. An apparatus as claimed in Claim 8 wherein the threshold temperature is about 200F.

1 -is-

10. An apparatus as claimed in any one of Claims 5 to 9 wherein the temperature sensing means acts to actuate commutation means for commutating from the freezing cycle to a defrost cycle.

11. An apparatus as claimed in any preceding claim wherein means are provided to perform a def rost cycle comprising supplying a defrost medium comprising refrigerant material whose temperature is more than OOC to said freezing members.

12. An apparatus as claimed in any preceding claim wherein means are provided to perf orm a defrost cycle which comprises supplying a hot gas def rost medium to said freezing members.

13. An apparatus as claimed in any preceding claim wherein temperature sensing means of the apparatus acts on commutation means to commutate from a defrost cycle to a freezing cycle.

14. An apparatus as claimed in Claim 13 wherein the temperature sensing means is disposed to sense refrigerant temperature and is calibrated to actuate said commutation means at a threshold temperature of from 35OF to 50OF (eg 35OF to 450F).

15. An apparatus as claimed in Claim 14 wherein the threshold temperature is about 400F.

c 1 C_ is

16. An apparatus as claimed in claim 13 wherein the temperature sensing means is disposed to sense defrost medium temperature and is calibrated to actuate said commutation means at a threshold temperature predetermined as representative of a condition in which the defrost cycle has caused release of ice formations from the evaporator.

17. An apparatus for the production of ice pieces which apparatus comprises a reservoir for containing a body of water, an evaporator for effecting freezing of water, said evaporator including at least one freezing member and being arranged for supply of refrigerant thereto for performing a freezing cycle and agitation means for agitating the body of water so that ice f ormed by the evaporator is clear, the apparatus forming an ice formation over the freezing member surfaces and the evaporator being so oriented that the formations, on release from the freezing member(s), separate from the -20 member each as a single piece by its buoyancy and elevates to the surface of the body of water for harvesting.

18. An apparatus as claimed in Claim 17 which includes freezing cycle termination means and determination means as defined in Claim 1.

19. An apparatus as claimed in Claim 18 wherein t 1 p- commutation means is provided for alternating between the freezing cycle and a defrost cycle in which a defrost medium is supplied to a freezing member to effect release of ice formation thereon.

is

20. An apparatus as claimed in any one of Claims 13 to 15 wherein the determination means comprises timer means as defined in Claim 4 or temperature sensing means as defined in any one of Claims 5 to 10.

21. An apparatus as claimed in any one of Claims 17 to 20 wherein means as claimed in any one of Claims 11 to 16 are provided for performing a defrost cycle.

22. An apparatus for the production of ice pieces, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

23. A method of producing high clarity ice pieces which method comprises disposing one or more freezing members in a body of water, performing a freezing cycle in relation to the freezing members to form ice formations thereon, terminating the freezing cycle when a desired level of ice formation is achieved, effecting removal of and harvesting said ice formations from said freezing members, characterized in that the body of water is rendered dynamic during at least part of said freezing cycle by paddle agitation means including one or more blades and operated such that a blade disturbs the surface of the water by penetration it at a rate of less r 1 than 15 penetrations per minute (eg 3 to 10 per minute), said desired level of ice formation preferably being detected by detection of a threshold value for a parameter predetermined as representative of said desired level.

24. A method as claimed in Claim 23 wherein the freezing cycle alternates with a defrost cycle which releases interfacial bonding of the ice formations to the freezing members.

25. A method as claimed in Claim 24 wherein the defrost cycle is performed with the freezing members so disposed that on release of the ice formations said members and said formations are immersed in the body of water and said released formations elevate to the water surface under their own buoyancy.

26. Ice in piece form whenever obtained by a method as claimed in any one of Claims 22 to 25.

Published 1990 atThe Patent office, State House. 66171 High Hooorn. London WC1R 4TP.Further copies maybe obtained from The Patent Office Wes Branch. St Mary CraY, Orpington. Kent BR5 3RD. Printed by MU!t'pl,--x techraques ltd, St May Cray, Kent. Con 1 '81

26. A method of producing high clarity ice pieces, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

27. Ice in piece from whenever obtained by a method as claimed in any one of Claims 23 to 26.

R 1 M- - - Amendments to the claims have been filed as follows is 1. An apparatus for the production of ice pieces which apparatus comprises a reservoir for containing a body of water, an evaporator for effecting freezing of water, said evaporator including at least one f reeiing member and being arranged for supply of refrigerant thereto for performing a freezing cycle and agitation means for agitating the body of water so that ice formed by the evaporator is clear, the apparatus in use forming an ice formation over the freezing member surfaces and the evaporator being so oriented that the formations, on release from the freezing member(s), separate from the member each as a single piece by its buoyancy and elevate to the surface of the body of water for harvesting.

2. An apparatus as claimed in claim 1 and including termination means for terminating the freezing cycle when the freezing cycle is complete as signified by a threshold extent of ice formation having taken place; and actuation means for determining when said threshold extent of ice formation has taken place and responsive thereto for actuating said termination means, said agitation means including an agitation member which is displaced in operation of said agitation means to disturb the water surface and the calibration of said actuation means for 'determining when said threshold extent of ice formation has taken place cooperating with the disposition of said agitation member to ensure that the freezing cycle is terminated without the agitation member ,7-0.

experiencing obstruction from the ice formed by the evaporator.

3. An apparatus as claimed in Claim 2 which includes commutation means for alternating between the freezing cycle and a defrost cycle in which a defrost medium is supplied to the freezing member(s) to effect release of ice formation thereon.

4. An apparatus as claimed in Claim 2 or Claim 3 wherein the actuation means for determining ice formation of a predetermined desired extent comprises timer means calibrated to actuate said termination means after a time lapse predeteremined as representive of said threshold extent of ice formation.

5. An apparatus as claimed in Claim 2 or Claim 3 wherein the actuation means for determining when said threshold extent of ice formation has taken place comprises temperature sensing means sensing the temperature of the refrigerant.

7. An apparatus as claimed in Claim 6 wherein the refriqerant line is a suction line defining a downstream - directed flow path from a freezing member to a compressor.

8. An apparatus as claimed in any one of Claims 5 to 7 wherein the temperature sensing means is caiibrated to actuate said termination means to cease the freezing cycle at a threshold temperature of from 150F to 300F.

9. An apparatus as clAimed in Claim 8' wherein the threshold temperature is about 200F.

10. An apparatus as claimed in any one of Claims 5 to 9 wherein the temperature sensing means acts to actuate commutation means for commutating between the freezing cycle and a defrost cycle.

11. An apparatus as claimed in any preceding claim wherein means are provided to perform a defrost cycle comprising supplying a defrost medium comprising refrigerant material whose temperature is more than OOC to said freezing member(s).

12. An apparatus as claimed in any preceding claim wherein means are provided to perform a defrost cycle which comprises supplying -a hot gas defrost medium to 25 said freezing member(s).

13. An apparatus as claimed in any preceding claim wherein temperature sensing means of the apparatus acts I'L ' on commutation means to commutate from a defrost cycle to a freezing cycle.

14. An apparatus as claimed in claim 13 wherein the temperature sensing means is disposed to sense 1 refrigerant temperature and is calibrated to actuate said commutationmeans at a threshold temperature of from 35OF to 500F.

17. An apparatus as claimed in any preceding claim the agitation means comprises a paddle which operates 4E o disturb the surface of the body of water.

18. An apparatus as claimed in any preceding claim wherein said evaporator comprises at least four freezing members.

19. An evaporator as claimed in any preceding claim 1 1 tl wherein said freezing members comprise elongate fingers having a vertical orientation.

20. An evaporator as claimed in any preceding claim and comprising a first open-topped vessel for containing a body of water in water-tight fashion, a second opentopped vessel disposed within the first and communicating therewith so as to receive water therefrom in use, at least one evaporator disposed with upright elongate freezing members thereof received through a base of the second vessel, lines for supply of refrigerant or defrost medium to said freezing members, said lines coupling to the evaporator without penetrating the open top of the second vessel, water supply means for supply of water to the first vessel of the apparatus and means for agitating the water surface within the open top of the second vessel and to sweep floating ice formations to and past an extremity of the second vessel.

21. An apparatus for the production of ice pieces, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

22. A method of producing high clarity ice pieces which method comprises disposing one or more freezing members in a body of water defined beneath a water surface with the freezing members disposed in upstanding orientation, performing a freezing cycle in relation to the freezing members to form ice formations thereon, terminating the -1 ki(.

freezing cycle when a threshold level of ice has been formed, effecting removal of said ice formations from said freezing members and harvesting said ice formations, characterized in that the body of water is rendered dynamic during said freezing cycle by paddle agitation means including one or more blades and operated such that a blade disturbs the surface of the water by penetration thereof at a rate of less than 15 penetrations per minute, the freezing cycle being terminated by termination means without said threshold level of ice formation bQing experienced by said paddle agitation means.

23. A method as claimed in Claim 22 wherein the freezing cycle alternates with a defrost cycle which releases interfacial bonding of the ice formations to the freezing members.

24. A method as claimed in qlaim 23 wherein the defrost cycle is performed with the freezing members disposed in vertical disposition.

25. A method of producing high clarity ice pieces, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.