Method and apparatus for ice blasting

Abstract

The invention provides an apparatus and method for partitioning continuously produced ice particulates and delivering them at a high velocity onto a substrate for treating the surface of the substrate. The apparatus includes a refrigerated curved surface that is brought into contact with water to form a thin, substantially uniform, ice sheet on the surface. This ice sheet is of such thickness as to contain stresses so that the sheet is predisposed to fracture into particulates. A harvesting blade is mounted to intercept a leading edge of the ice sheet and to fragment the ice sheet to produce ice particulates. These ice particulates enter into an inlet where they are fluidized and drawn into a manifold that extends substantially along the length of the harvesting blade. The manifold partitions the particulates into separate delivery tubes where they are ejected from nozzles to the workpiece. The manifold can be created to either evenly or unevenly distribute ice particulates to the delivery tubes. The flow of particulates through the nozzles can also be individually controlled by using a pressure regulator to control the amount of pressurized air entering the nozzles.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a method and apparatus for formation and delivery of a supply of frozen liquid particulates and directing them through separate, individual conduits. More particularly, the present invention relates to a method and apparatus for partitioning a supply of ice particulates, directing the ice particulates into separate, individual delivery tubes, and ejecting the ice particulates at workpieces with complex shapes and surface features.

BACKGROUND OF THE INVENTION

[0002] In recent years, there has been increasing interest in the use of ice blasting techniques to treat or otherwise clean surfaces. For certain applications, ice blasting provides significant advantages over other cleaning techniques such as blast cleaning with high pressure water, steam, abrasive media, or dry ice. The techniques can be used to clean and even to remove loose material, chips, flashings, and burrs from production metal components. Because water in either frozen or liquid form is environmentally safe and inexpensive, ice blasting reduces waste disposal problems relative to competing techniques, such as sand blasting or solvent cleaning. This advantage is particularly notable in manufacturing environments where continuous operations can generate huge amounts of waste from other processes.

[0003] The advantage of ice blasting has lead to the development of a variety of devices designed to perform surface treatment procedures by delivering a high pressure spray containing fluidized ice particulates. Typical ice blasting devices transport ice particulates via suction to a blast nozzle for discharge onto a work surface. Ice blasting, like all particulate blasting, is a “line-of-sight” operation. This means that each nozzle can only be directed at one area of a workpiece. Many manufacturing applications, however, require cleaning a workpiece that is complex in shape and surface detail. Therefore, in a typical ice blasting operation, complete treatment of a workpiece often requires manipulation by either a robot or through human intervention. Both robotic implementation and human intervention add cost and additional precious cycle time for each part produced.

SUMMARY OF THE INVENTION

[0004] The invention provides an apparatus for partitioning a supply of ice particulates for use in ice blasting work. Once partitioned, the ice particulates can be directed from multiple nozzles at a predetermined velocity and onto a workpiece. Since ice particulates are ejected from multiple nozzles, a complex workpiece can be treated to remove contaminates, coatings, or oxides, or to otherwise produce a smooth, clean surface without having to reorient the workpiece or adjust the orientation of the nozzle. Furthermore, since the velocity of ice particulates exiting the nozzle can be individually adjusted, the invention can treat more sensitive areas of the workpiece contemporaneous with the treatment of areas requiring a higher ice particulate velocity without significant risk of damage to the more sensitive areas.

[0005] In general, an embodiment of the invention provides an ice particulate making apparatus with a rotating cooling drum having an outer surface on which a thin sheet of ice is formed. The thin sheet of ice is then thrust against a harvesting blade that fractures the sheet of ice into frozen ice particulates. A manifold, disposed adjacent to the harvesting blade, divides the ice particulates into individual, separate delivery tubes. The ice particulates are eventually ejected from a nozzle located at the end of each delivery tube. An air stream supply introduces a stream of air into the nozzle which is of the ejector type that creates a suction force that draws atmospheric air to fluidize the ice particulates causing them to be drawn through the manifold, down the delivery tube, into the nozzle where they are accelerated to a high velocity and out the nozzle where they are directed at the workpiece.

[0006] In accordance with another embodiment of the invention, an apparatus for directing ice particulates at a work piece includes a rotary cooling member having an outer surface cooled by refrigerant and rotating through a bath of water forming a thin sheet of ice upon the outer surface. Extending along the length of the outer surface is a harvesting blade disposed adjacent to the outer surface. The harvesting blade is oriented to enable fragmenting of the thin sheet of ice into ice particulates. A manifold is located adjacent to the harvesting blade to collect ice particulates and partition them. The manifold has at least two chambers, each chamber having a gathering end located adjacent to the harvesting blade and a discharge end for distributing the partitioned ice particulates. Secured to the discharge end of each chamber is a delivery tube. The delivery tubes transport the ice particulates to nozzles directed at the workpiece. An airstream is introduced into the nozzle and directed out of the nozzle. The direction of flow of the airstream produces a suction force by Venturi action. This suction force fluidizes the particulates and draws them through the manifold, into the delivery tubes and out of the nozzles to the workpiece.

[0007] In accordance with another embodiment of the invention, the ice particulates are ejected out of each of the nozzles towards the workpiece at different orientations. Use of multiple nozzles allows the workpiece to be addressed by ice particulates on all sides by orienting the nozzles to meet the application's particular needs. Furthermore, a pressure regulator may be located at each nozzle to control the airstream introduced into the nozzle. By controlling the airstream being introduced into the nozzle, one can control the velocity of the ice particulates exiting the nozzle. Such control allows one to address more sensitive areas of the workpiece with a lower velocity ice blast, thus, reducing the risk of damage to the workpiece.

[0008] The invention also provides a method of partitioning a stream of continuously produced particulates. The method comprises continuously producing ice particulates formed on a rotary cooling member and removed with a blade; positioning a manifold inlet that supplies at least two particulate delivery tubes adjacent to the ice removal blade; introducing a flow of air into the nozzles so as to create a suction force that draws the particulates through the manifold and into the delivery tubes in a fluidized stream; partitioning the fluidized ice particulate stream through the manifold and into the delivery tubes; and dispensing the particulate streams from the delivery tubes through the nozzle towards a workpiece. The fluidized ice particulates are dispensed from the delivery tubes through a nozzle. Dispensing of the ice particulates can be at different orientations by orienting the nozzle to suit the particular needs of an application.

[0009] In another embodiment of the invention, a regulator may be located at each nozzle to control the stream of air introduced into the nozzle. By controlling the stream of air into the nozzle, the velocity of the ejected ice particulates can be controlled; thus, ejecting of the ice particulates towards more sensitive areas of the work piece may be accomplished with reduced risk of damaging the work piece.

[0010] In a further embodiment of the invention, the method of partitioning ice particulates may include introducing a stream of air across the outer surface of the rotary member to increase fluidization of the ice particulates. Increased fluidization of the ice particulates will help reduce the incidents of blockages and the agglomeration of ice particulates along the delivery path. The reduction in stationary ice particulates allows the ice blasting process to occur more efficiently, thus reducing the need for maintenance and allowing the ice blasting procedure to operate more continuously.

[0011] In yet a further alternative embodiment of the invention, improved ice particulate fluidization is achieved by vibrating the manifold. By vibrating the manifold, blockages and agglomerations of ice particulates will be reduced, and the efficiency of the ice blasting process will be increased.

[0012] The present invention provides an ice blasting method and apparatus capable of use in a manufacturing environment that can provide the environmental advantages that ice blasting permits, while maximizing the economic advantages through reductions in handling and cycle time. In a preferred embodiment, the method partitions ice particles into precise and consistent divisions, each to be delivered to different areas of the workpiece. The number of divisions are determined from the part geometry and cleaning requirements. The blasting operation is controlled by a predetermined blast air pressure. Such a preferred method and apparatus is easily modifiable to accommodate other part geometries when production parts change.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0014] FIG. 1 is a simplified schematic of the ice blasting apparatus of the invention;

[0015] FIG. 2 is a an end view of the ice particulate generating equipment showing a rotary member, harvesting blade, thin sheet of ice; and cross section of a manifold chamber;

[0016] FIG. 3 is a schematic showing an air stream being introduced from an air supply to create a suction force in three separate nozzles; and

[0017] FIG. 4 shows the ice blasting apparatus installed in a production line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] The invention provides an apparatus and a method of continuously producing ice particulates, partitioning the ice particulates into separate delivery conduits, and ejecting the ice particulates at a controlled velocity onto a workpiece. The ice particulates are formed from fragmenting a thin, curved sheet of ice. In the specification and claims, the phrase “thin, curved sheet” refers to a sheet of such curvature and thickness that, as a result, the sheet has residual stresses and a thermal gradient so that it is predisposed to self-fragmentation. An example of such a thin, curved sheet is a cylindrical sheet is a sheet about 1.5 mm thick with a radius of curvature of about 100 mm. Preferably, this sheet is from about 1.0 to about 2.0 mm thick, and has a radius of curvature of about 50 mm to about 150 mm. Clearly, larger or smaller apparatus are also useful and are within the scope of the invention.

[0019] According to the invention, the ice particulates are kept in constant motion and are fluidized so that they do not come to rest relative to any part of the apparatus and do not come into stationary contact with each other. Such contact may cause the ice particulates to cohere and form larger ice particulate blocks that may cause blockages in the apparatus. Moreover, the flow path through which the ice particulates are carried by a fluidizing gas, such as cold air, is smooth and devoid of any abrupt changes in flow cross sectional area that may lead to the deposition and subsequent accumulation of ice particulates that may form blockages. In one embodiment, the flow conduit has a diameter of about 25 to about 50 mm. In order to minimize any melting of the ice particulates that may lead to subsequent agglomeration or adherence and blockage, components of the apparatus that come into contact with the ice particulates are preferably fabricated from materials that are smooth and have low thermal conductivity. Polymeric materials are preferred, especially non-stick plastics such as TEFLON™ or other fluoropolymers, that may be used as an interior coating.

[0020] The apparatus of the invention may be better understood with reference to the accompanying figures that schematically represent preferred embodiments of the apparatus for making ice particulates, partitioning the ice particulates, and delivering these ice particulates through a nozzle onto the surface of a workpiece. Clearly, other embodiments are also within the scope of the invention, but reference to the preferred embodiments of the figures facilitate an explanation of the aspects of the invention.

[0021] FIG. 1 schematically illustrates the ice blasting operation. In accordance with the invention, an ice blaster 10 comprises a particle generator 12 that continuously produces ice particulates that are partitioned by the manifold 40 into separate, individual delivery tubes 60, and eventually, ejected through a nozzle 70 and delivered to the workpiece 80. The manifold 40 contains an inlet 42 for receiving particulates into the manifold 40 from the particle generator 12. The inlet 42 is positioned adjacent to the particle generator 12 such that all of the particulates generated by the particle generator 12 enter the manifold 40 through the inlet 42. At least one end of the inlet 42 is open to receive air from outside the particle generator 12. The at least one open end of the inlet 42 permits the particulates to be fluidized by atmospheric air while avoiding the creation of a vacuum.

[0022] A stream of air is introduced through the use of an air supply 74 and air stream supply lines 72 into the nozzles 70. The air supply 74 is generally either an air compressor or a pressurized cylinder. The air introduced into the nozzle flows out of the nozzles 70 creating a suction force along the length of the delivery tube 60 and into the manifold 40 drawing ice particulates fluidized by atmospheric air at inlet 42 from the particle generator 12, through the manifold, into the delivery tube 60 and through the nozzles 70 and out toward the workpiece 80. The velocity of the ice particulates being ejected out of the nozzle 70 can be controlled by regulating the pressure of the pressurized air introduced into the nozzle. The supply lines 72 each have a pressure regulator 76 to regulate the pressure of the pressurized air in the supply lines 72. The pressure regulators may be independently adjusted to individually control each air supply line 72 to provide a varied velocity of the ice particulates to different areas of the workpiece 80.

[0023] Turning now to FIG. 2, the ice blaster 10 continuously produces ice particulates by way of a particle generator 12. The particle generator has a rotary cooling drum 20 that is suspended in a water bath 24 wherein the water for the water bath is supplied from the water supply 16. The rotary cooling drum 20 is suspended in the particle generator 12 such that it is free to rotate through the water bath 24 while the ice blaster 10 is in operation. The rotary cooling drum 20 is cooled by way of refrigerant (not shown). As the drum 20 rotates counter-clockwise through the water bath 24, a thin, curved sheet of ice 26 is formed on the outer surface 22 of the drum 20. As the drum 20 continues to rotate, the thin, curved sheet of ice is carried out of the water bath and urged against a harvesting blade 28 which clears the drum 20 of the thin, curved sheet of ice 26. The now cleared outer surface 22 is resubmerged in the water bath 24 where a new thin, curved sheet of ice 26 is created and the process of forming ice particulates continues.

[0024] It should be noted that the thin, curved sheet of ice 26 is subject to stress as a result of its shape and a temperature gradient that extends through its thickness so that it is predisposed to self fragment into ice particulates. The size distribution of these ice particulates is dependent upon the thickness, temperature, and the radius of curvature of the thin, curved sheet of ice 26, which are in turn dependent upon the rate of rotation and temperature of the drum 20, and the radius of the drum 20. These parameters are selectively controlled to achieve self fragmentation into fine particles suitable for blasting without further fragmentation processes.

[0025] Referring to FIGS. 1 and 2, a manifold 40 is disposed adjacent to the harvesting blade 28 to receive the harvested frozen ice particulates. The manifold 40 contains an inlet 42 located adjacent to and across the entire length of the drum 20 and an outlet 44 located distal from the drum 20. The manifold 40 contains at least two inner chambers 46 for partitioning the ice particulates as they enter into the manifold 40. Each inner chamber 46 has a gathering end 48 located at the inlet 42 of the manifold 40 and a discharge end 50 located at the outlet 44 of the manifold 40. As pressurized air is introduced to the nozzle 70, a suction force is developed at the discharge end 50 to draw ice particulates fluidized by atmospheric air from the harvesting blade 28 into the manifold inlet 42. Thus ice particulates are partitioned and distributed for ejection from the nozzle 70 to the workpiece 80 based upon the number of inner chambers 46 and the size of the inner chambers 46. The inlet 42 extends substantially along the entire length of the drum 20. One edge of the inlet 42 is sealed against the harvesting blade 28 by mechanical pressure. The other edge of the inlet 42 curves over above the sheet of ice 26. The ice particulates are thus captured in the inlet 42 where they are immediately fluidized by atmospheric air and drawn into the chambers of the manifold 40.

[0026] At least two delivery tubes 60 are connected to the outlet 44 of the manifold 40. Generally, the number of delivery tubes 60 will equal the number of inner chambers 46 in the manifold 40; however, it is possible that one inner chamber 46 may have multiple delivery tubes 60 connected to the gathering end 48 of that inner chamber 46. The delivery tube 60 has a receiving end 62 that is proximal to the outlet 44 of the manifold 40. The receiving end 62 is fluidly connected to the gathering end 48 of the inner chamber 46. The delivery tube 60 also has a delivery end 64 that is distal to the outlet 44 of the manifold 40. A nozzle 70 is secured to the delivery end 64 of the delivery tube 60. A stream of air from an air supply source 74 is introduced into the nozzle 70 through the air stream supply line 72.

[0027] As the stream of air is introduced into the nozzle 70, a suction force is created in the manifold 40 via delivery tube 60. This suction force draws the ice particulates into the chambers of the manifold, thus, partitioning the continuous supply of ice particulates into separate delivery tubes 60 and ejecting the ice particulate out of separate nozzles 70 to be directed at the workpiece 80.

[0028] FIG. 3 shows three separate nozzles 70 with a stream of air introduced into each from one common air supply source 74. Each of these three nozzles may suitably have an equal stream of air supplied to it, thus resulting in a similar blasting force achieved at the workpiece 80 of the ice particulates, though the pressure of the air supply can be selectively varied for each nozzle for a desired differential blast force if needed. An arrangement such as this allows for a blasting of the workpiece 80 from multiple orientations. The addition of a pressure regulator 76 can alter the air pressure being introduced into the nozzle 70, thus, altering the blast force of the particulates. With such an arrangement as this, not only can the workpiece 80 be blasted from different orientations, but more sensitive areas of the workpiece can receive a lower blast force of the ice particulates by adjusting the pressure regulator 76 to a lower pressure, thus, causing a lower velocity of the ice particulates. It can be readily understood by those skilled in the art that multiple air supply sources can be used to achieve this same feature.

[0029] The amount of ice particulate directed towards the workpiece 80 can also be varied by varying the length of the gathering end 48 of the inner chamber 46 of the manifold 40. The manifold is capable of being divided into several different chambers each with a gathering end 48. The amount of ice particulate entering the chamber 46 will be determined by the length of the gathering end 48 of the chamber. For example, if the manifold were divided into three separate chambers, one chamber with a gathering end occupying 60% of the total length of the harvesting blade, one chamber with a gathering end occupying 30% of the overall length of the harvesting blade, and one chamber with a gathering end occupying 10% of the overall length of the harvesting blade, the total ice particulates produced by the ice particulate generator 12 will be partitioned in proportion to the length occupied by the gathering end of each inner chamber. Other numbers of chambers and percent distributions are also within the scope of the present invention. Therefore, the amount of ice particulate blasted at the workpiece 80 can be easily varied along with the orientation that the ice particulates are ejected at to accommodate workpieces of different shapes and areas of the workpiece that may be more sensitive.

[0030] As shown in FIG. 4, the ice blaster 10 may be mounted above a production line 90 to address workpieces as they traverse past the nozzles 70. The ice blaster 10 of the present invention is particularly suited for this type of arrangement as various amounts of ice particulate can be ejected from various nozzles at different blast forces. This allows the ice blasting apparatus 10 to blast an entire workpiece 80 without having to rotate the workpiece or reorient the nozzles. Thus, the apparatus of the present invention is ideally suited for use to deburr or otherwise treat the surface of a workpiece because it can be accomplished in a continuous low-cost manner.

[0031] In a further preferred embodiment of the ice blaster of the present invention, the manifold 40 is equipped with a vibrator to dislodge any ice that may settle in its chambers and to prevent agglomeration of ice in the manifold 40. The addition of a vibrator improves the fluidization of ice particulates into the stream of air. This improved fluidization has the advantage of allowing the ice blaster to run continuously for longer periods of time without maintenance. Another means of improving fluidization is to introduce a stream of air across the outer surface 22 of the rotary cooling drum 20 towards the manifold inlet 42. This additional stream of air provides enhanced fluidization of the particles, as compared to normal fluidization by atmospheric air, as they are harvested from the harvesting blade 28. Once again, improved fluidization of the ice particulates leads to less blocking and longer continuous operation prior to need of maintenance.

[0032] The invention also provides a method of blasting surfaces with ice particulates. In accordance with the method, water is frozen into a thin, curved sheet of ice, preferably by freezing water onto a cylindrical surface. The thin, curved sheet of ice is of such a thickness that temperature differences between its opposing curved faces results in stress that predisposes the thin, curved sheet of ice to self-fragmentation into ice particulates. This stress-cracked thin, curved sheet of ice is fragmented by impacting the leading edge of the thin, curved sheet with a harvesting blade that extends along the leading edge of the sheet. The leading edge of the sheet is preferably of substantially uniform thickness along its length for more uniformly sized ice particulates. Fragmented ice particulates are drawn through suction into a manifold where the ice particulates are both partitioned and fluidized in air or another gas without melting. The fluidized ice particulates are then carried through separate, individual chambers into separate, individual delivery hoses from which the ice particulates are ejected through nozzles onto a workpiece that is being ice blasted. Ice particulates pass continuously from the cooling member to the discharge nozzle.

[0033] In order to fluidize, partition, carry, and accelerate the speed of the ice particulates entering the manifold, in one embodiment high pressure air is introduced into the nozzle, thereby creating an area of low pressure behind its entry point in the nozzle. The low pressure area is in fluid communication with the delivery tube and draws, by suction, ice particulates from the fragmenting step into the manifold, and then partitioned into the delivery tubes. The high velocity of the air at the vicinity of the nozzle tip, ahead of the entry point of the high pressure air, accelerates the ice particulates for the ice blasting operation.

[0034] In one aspect of the method of the invention, it is preferred to fluidize the ice particulates with cold air above 0° C. Conventionally, it might be expected that such air would cause the particulates to melt and thus diminish the effect of ice blasting. Instead, since the ice particulates are only in contact with the air for a short period of time, measured in seconds, there is insufficient time for significant heat transfer to melt all but the smallest particulates (which are not effective for blasting, in any event). The advantage of using air above 0° C. is that parts of the ice blasting apparatus such as valves do not become frozen in place (i.e., full open) after prolonged, continuous use. Thus, contrary to the conventional approach, the invention prefers (but is not limited to) the use of a carrier gas or air and a temperature in the range of about 0° C. to about 50° C., preferably about 5° C.

[0035] Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function, and not only structural equivalents, but also equivalent structures.

[0036] While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Claims

1. A method of partitioning a stream of continuously produced particulates, the method comprising:

(a) continuously producing ice particulates using a rotary cooling member having a surface on which ice is formed and an ice removal blade;

(b) positioning a manifold inlet adjacent to the ice removal blade, the manifold inlet supplying at least two nozzles via delivery tubes;

(c) introducing a flow of air into the at least two nozzles to draw the particulates into the manifold in a fluidized stream;

(d) partitioning the fluidized particulate stream through the manifold and into the at least two nozzles; and

(e) dispensing particulate streams of fluidized particulates from the at least two nozzles.

2. The method of claim 1, wherein the ice particulates are formed by continuously freezing water on the surface of the rotary cooling member, the surface being curved and producing a thin, curved sheet of ice subject to self fragmentation; and rotating the rotary cooling member causing the leading edge of the thin, curved sheet of ice to impact the removal blade.

3. The method of claim 1, wherein the fluidized particulates are ejected at different rates from the at least two nozzles.

4. The method of claim 1, wherein the particulates ejected from each of the nozzles are directed at a workpiece at a different orientation.

5. A method of partitioning a continuously produced stream of ice particles, the method comprising:

(a) continuously freezing water into a thin, curved sheet of ice subject to self-fragmentation, the self-fragmented ice providing a source of ice particulates;

(b) introducing a flow of air into at least two nozzles each being in fluid communication with the source of ice particulates via a delivery tube, the flow of air being sufficient to develop a suction force along at least a portion of each of the delivery tubes, the suction force drawing the ice particulates into the nozzles via the delivery tubes;

(c) continuously harvesting at least a portion of the self-fragmented thin, curved sheet of ice in the form of ice particulates directly into a fluidized stream of particulates in air that is partitioned to flow through the at least two delivery tubes; and

(d) ejecting the ice particulates from the end of each nozzle.

6. The method of claim 5, wherein the nozzle is able to control the velocity of particulates therethrough.

7. The method of claim 5, wherein the nozzles supply particulates at different velocities.

8. The method according to claim 5, wherein the supply of air introduced to each nozzle is provided from a common source.

9. The method according to claim 6, wherein the pressure of the air supplied to one nozzle is different from any other nozzle, the difference in nozzle air pressure being used to control the velocity of the ice particulates exiting the nozzle.

10. The method according to claim 5 further comprising directing an air supply at the harvested ice particulates to help promote ice particulate fluidization.

11. The method according to claim 5 further comprising vibrating the manifold to promote fluidization.

12. An apparatus for partitioning ice particles, the apparatus comprising:

(a) a rotary cooling member having an outer surface, the rotary cooling member being cooled by refrigerant such that liquid freezes on the outer surface;

(b) a harvesting blade disposed adjacent to the outer surface to remove frozen particulates from the surface;

(c) a manifold having an inlet disposed to collect frozen particulates from the harvesting blade, and an outlet;

(d) at least two delivery tubes, said delivery tubes having a receiving end fluidly coupled to the outlet of the manifold and a delivery end, the delivery end having a nozzle for ejecting frozen ice particulates from the end of each of said delivery tubes; and

(e) an air stream supply that introduces an air stream into each of said nozzles, said stream of air producing a suction force to draw harvested frozen particulates from the manifold, through the delivery tube, into the nozzle and eject them from the nozzle when said stream of air is directed through said nozzle.

13. The apparatus of claim 12, wherein the surface of the rotary cooling member is curved, and the frozen particulates are ice particulates formed from a thin, curved sheet of frozen water on the surface of the rotary cooling member, the sheet of ice being subject to self-fragmentation.

14. The apparatus of claim 12, wherein the manifold has at least two harvesting chambers; each harvesting chamber having an inlet end and an outlet end, the inlet end directed at the source of frozen particulate and located adjacent to the source of particulate such that a suction force created in said nozzle draws a portion of the ice particulate into a chamber of the manifold, and the outlet end being connected to the receiving end of said delivery tube.

15. The apparatus of claim 12, wherein the ice particulates are directed at a workpiece at different orientations.

16. The apparatus of claim 12 further comprising a single source of air supplying said nozzles.

17. The apparatus of claim 12, further comprising a means for directing an air supply across the outer surface of the rotary member to promote fluidizing of the harvested the ice particulates.

18. The apparatus in claim 12, further comprising a means for vibrating the manifold to promote fluidization of the harvested ice particulates.

19. An apparatus for directing ice particles at a workpiece, the apparatus comprising:

(a) a rotary cooling member having an outer surface, the rotary cooling member being cooled by refrigerant to at least 0° C., the rotary cooling member being rotated in a bath of water, a thin sheet of ice being formed on the cylindrical surface when water contacts the surface;

(b) a harvesting blade disposed adjacent to the outer surface of the rotary member, the harvesting blade extending along the length of the outer surface of the rotary member, the harvesting blade oriented to enable fragmenting the thin sheet of ice to form ice particulates;

(c) a manifold having an inlet disposed adjacent to the harvesting blade to collect ice particulates and having an outlet that distributes the ice particulates, the manifold having at least two chambers, each of the chambers having a gathering end and a discharge end, the gathering end being located adjacent to the harvesting blade, the discharge end distributing partitioned ice particulates; and

(d) at least two delivery tubes, the at least two delivery tubes having a receiving end and a delivery end, the receiving end fluidly coupled to the discharge end of the manifold chamber to receive the partitioned ice particulates into the delivery tube, the delivery end connecting to a nozzle to deliver the ice particulate to the workpiece;

(e) an air stream supply that introduces an air stream into each of the nozzles, the stream being introduced between the nozzle and the delivery end of the at least two delivery tubes, said stream of air producing a suction force to draw harvested frozen ice particulates from the manifold and through the delivery tube and eject them from the nozzle when said stream of air is directed through said nozzle.

20. The apparatus in claim 19 wherein the ice particulates are ejected out of each of the nozzles towards a workpiece at a different orientation.

21. The apparatus in claim 19, further comprising a pressure regulator to control the air stream supply entering the at least two nozzles, said regulator controlling the pressure of the air stream into the nozzles.