GB2072030A

GB2072030A - Universal batch processor

Info

Publication number: GB2072030A
Application number: GB8107316A
Authority: GB
Original assignee: Chemetron Process Equipment Inc
Current assignee: Chemetron Process Equipment Inc
Priority date: 1980-03-10
Filing date: 1981-03-09
Publication date: 1981-09-30
Also published as: GB2072030B

Abstract

A universal processor (10) for batch processing of food products and other liquid or semisolid materials has a hollow-walled cylindrical heat transfer drum (30) adapted to be immersed within a kettle (18) of material for heating or cooling thereof. A rotatable scraper (16) has sets of scraper blades (70, 72) in wiping contact with the inner and outer sidewalls of the drum (30) and is rotated during processing to preclude material build-up on the drum (30). In preferred forms, a drive rotates the drum (30) in a direction opposite to the rotation of the scraper (16). Spiral flighting (74, 76) on the scraper (16) adjacent the sidewalls serves to agitate the material in a predetermined manner for enhanced heat transfer between the drum (30) and material, and for improved blending of ingredients in compounded materials. The drum (30) is particularly dimensioned relative to the kettle (18) for more uniform heat transfer throughout the batch of material. <IMAGE>

Description

SPECIFICATION Universal batch processor This invention relates to universal batch processors for food and chemicals and is particularly concerned with a processor having an immersible scraped surface heat exchange element and cooperable agitating structure for selectively blending, heating and cooling small batches of materials.

Heat exchange operations occur in the processing of most chemicals and food products. The criticality of the heat exchange operation is a function of the material being processed, but in view of rapidly rising energy costs, heat exchanger efficiency is becoming increasingly more important in almost all processing plants.

Perhaps one of the most efficient commercially available heat exchangers is the VOTATOR (Registered Trade Mark) scraped surface heat exchanger manufactured by Chemetron Process Equipment, Inc., one embodiment of which is disclosed in United States Letters Patent No. 3,430,928. In the VOTATOR device, a cylindrical processing chamber surrounded by a heat exchange jacket contains a rotatable bladed mutator whereby the heat exchange surface is continuously scraped to enhance heat transfer between the material in the chamber and the surrounding jacket.

A variation of the basic VOTATOR scraped surface exchanger is disclosed in United States Letters Patent No. 4,126,177. There, an inner heat exchange jacket is disposed within the processing chamber concentric with the outer jacket such that dual opposed heat exchange surfaces are presented to define the sidewalls of the chamber. A special rotating cage is provided for scraping both the inner and outer heat exchange surfaces.

While the devices described above are well suited for their intended purposes, they are by design adapted primarily for continuous processing as opposed to batch type processing. Though small batches of material may be passed through these machines, they must be thoroughly cleaned after each product change; the cleaning process is not only time consuming, it usually results in the loss of material as well. Moreover, the machines of this type are relatively expensive and must be used in high volume operations to be economically feasible.

Despite the increased application of economy of scale principles, there still exists today in the food and chemical processing industry a need for efficient small batch processing equipment. Typical heat exchange apparatus for batch processing comprises a jacketed kettle utilized in cooperation with some form of mechanical agitator. Heat exchange fluid is circulated through the hollow walls of the jacketed kettle, while material contained in the kettle is agitated to enhance heat transfer. Since this equipment is relatively inexpensive in comparison with the previously described scraped surface exchangers, it is much better suited for use in processing small batches of material. For example, a packager of frozen dinners may utilize such equipment for puddings, sauces, or similar foods to be included in their dinners.

The jacketed agitated kettles are unfortunately not very efficient in comparison with other types of heat exchangers. Thus, while they represent a relatively low initial outlay, operating costs may be undesirably high. Moreover, the special jacketed kettles required in such heat exchange systems are themselves significantly more expensive than standard single-wall kettle, and consequently it is not practical to employ the more expensive jacketed kettles in other processing steps which may be required.

Hence, a single batch of material may be formulated in one kettle, processed in a jacketed kettle, and then held in yet another kettle for packaging or subsequent processing. Obviously, it would be much more desirable to be able to use only a single kettle for all steps in the preparation of a batch of material.

One attempt to increase the efficiency of such batch-type systems is disclosed in United States Letters Patent No. 1,962,803 issued to Bruins. There, rotatable heat exchange elements are immersed within the material as opposed to utilizing a jacketed container. While the heat exchange elements of the apparatus of United States Patent No. 1,962,803 are drumlike in construction, no mention or suggestion is made of scraping the inside surface of the elements, nor is there any discussion of the importance of the configuration of the heat exchange elements with respect to the configuration of the holding tank. Additionally, the construction of the apparatus makes it much more suited for continuous processing than batch-type processing.

The present invention provides a universal batch processor for material contained in a kettle or other vessel, said processor including: a heat transfer element which can be immersed in material contained in a said vessel of suitable size, said element comprising an open-ended, hollowwalled tubular drum presenting inner and outer sidewalls and a closed annular cavity between the sidewalls; a scraper element having scraper blades in operative engagement with said sidewalls externally of said cavity; means for circulating heat exchange fluid through said cavity in the drum; and means for rotating one of said elements relative to the other about the axis of said drum whereby to effect scraping of the inner and outer sidewalls simultaneously.

The present invention also provides a universal batch processor for liquid and semisolid material, said processor including: an open top vessel adapted to contain an amount of a said material; a heat transfer element adapted to be immersed within a said material when the material is disposed within said vessel, said element comprising an open-ended, hollow-walled tubular drum presenting inner and outer sidewalls and a closed annular cavity between the sidewalls; a scraper element having scraper blades in operative engagement with said sidewalls; means for circulating heat exchange fluid through said cavity in the drum; and means for rotating one of said elements relative to the other about the axis of said drum whereby to effect simultaneous scraping of the sidewalls when the heat transfer element is immersed within said material.

The processor of the present invention offers high efficiency and versatility in batch processing of food and chemical products by the provision of cooperable heat exchanger and agitator elements adapted to be immersed in a batch of materials contained in a kettle or similar vessel. In combination the elements can mix, blend, heat or cool virtually any liquid or semisolid material.

The heat exchanger and agitator elements are preferably pivotally mounted upon a floor support which may be adjustable and which is such that they may be easily lowered into and raised from an open vessel of material to be processed. The support may be rendered portable to facilitate transfer of the elements from one vessel to another as desired.

The heat exchange element is of tubular-drum construction, preferably dimensioned such that equal volumes of material are disposed inboard and outboard of the heat exchange element when it is concentrically disposed within a complementally sized vessel. The agitator element has scraper blades for both the inner and outer heat exchange surfaces of the heat exchanger element to maximize the efficiency of heat transfer between the heat exchanger and the materials in the vessels. Reverse spiral flighting may be provided on the agitator element to create desired movement of the material axially of the vessel to further enhance heat transfer and to effect mixing of the ingredients in compounded materials.

The invention will be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a side elevation view of a universal batch processor according to the present invention, certain parts thereof being broken away, or shown in cross-section, to reveal details of construction; Figure 2 is an enlarged plan view of the vessl and parts therewithin of the processor of Figure 1; Figure 3 is an enlarged, fragmentary, crosssectional view of the vessel and parts of Figure 2; and Figure 4 is a vertical cross-sectional view of the heat exchanger and scraper elements showing the arrangement of the flighting structure.

In the drawings, there is shown a universal batch processor 10 comprising a support 12, a heat transfer unit 14 rotatably mounted on the support 12, and a scraper-agitator assembly 16 also rotatably mounted on the support 12 and disposed in cooperable engagement with the heat transfer unit 14. The processor 10 is shown in an operable position relative to a complementally sized hemispherical kettle 18 adapted to contain a quantity of material to be processed (not shown).

The support 12 includes a chassis 20 provided with four floor-engaging wheels 22 (only two of which are shown in Figure 1), an upstanding stanchion 24 projecting from the chassis 20, and a support member 26 pivotally mounted at the uppermost end of the stanchion 24 for swinging movement about a transverse horizontal axis 28. The chassis 20 may additionally be provided with locators (not shown) in order to properly position the processor 10 relative to the kettle 18 as will be explained hereinbelow.

The kettle 18 is of conventional hemispherical construction whereby cleaning and material removal is facilitated. The kettle 18 is provided with three legs 28 for supporting the material to be processed at a predetermined height about the floor. In the alternative, kettle 18 may be provided with structure to permittipping about a horizontal axisforfurther facilitating removal of material from the kettle. It is also contemplated that the kettle 18 might be removably supported directly upon the support 12 of the processor 10 rather than being independently supported as shown in the drawings.

The heat transfer unit comprises a hollow-walled open-ended, tubular drum 30 presenting inner and outer cylindrical sidewalls 32,34 respectively, and a closed annular cavity 36 concentrically disposed intermediate the sidewalls 32,34. A plurality of spiral baffles 38 are arranged in a double helix along the length of the cavity 36 to define dual spiral flowpaths 40a, 40b (Figure 3) therewithin, the helixes being interconnected at the uppermost end of the cavity 36 such that the flowpaths 40a, 40b are connected in series for the purpose to be described hereinbelow.

A tubular ring 42 mounted at the lower end of the drum 30 is divided internally into a pair of segregated chambers 44a, 44h each communicating with a respective one of the flowpaths 40a, 406. Heat transfer media is adapted to be circulated through the drum 30 from chamber 34a along flowpaths 40a, 40b to the chamber 44b in a manner to be described hereinbelow.

The drum 30 is concentrically supported about a normally upright shaft 46 by sets of three upper and lower spokes 48, 50, respectively, which extend from the lowermost end of the shaft 46 to the tubular ring 42. As shown for example in Figure 2, the three spokes 48 and the three spokes 50 are symmetrically arranged in alternating sequence about the axis of the shaft 46. For a purpose to be explained, two of the spokes 48, designated 48a in Figure 2, communicate with chamber 44b and two of the spokes 50, designated 50b in Figure 2, communicate with the chamber 44b.

As shown for example in Figures 2 and 3, the shaft 46 is formed from a pair of concentric tubes 52, 54 such that there is presented segregated outer and inner passageways 56, 58, respectively, extending substantially the full axial length of the shaft 46.

Considering specifically Figure 3, there is shown that the lowermost end of outer passageway 56 communicates with the upper spokes 48a, whereas the lowermost end of the passageway 58 communicates with the lower spokes 50b. A fitting 60 is coupled to the uppermost end of the shaft 46 by rotary seals (not shown) and includes an inlet 62 which communicates with the outer passageway 56 and an outlet 64 which communicates with the inner passageway 58.The inlet 62 is adapted to be coupled to a source of heat transfer fluid, such as water or brine, and the outlet 64 is adapted to be coupled to a suitable discharge whereby heat transfer fluid may be circulated through the heat transfer unit 14 along the following path: from inlet 62 to passageway 56, through spokes 48a, to chamber 44a, up flowpath 40a (axially upwardly around the drum 30), down flowpath 40b (axially downwardly around the drum 30) to chamber 446, through spokes 50b and passageway 56 to outlet 64.

The upper end of the shaft 46 is rotatably mounted to the support member 26 by a pair of bearings 66 axially spaced along the shaft 46. Thus, the heat transfer unit 14 is carried in depending relation to the member 28 when the latter is pivoted to its lower most position as shown in Figure 1.

The scraper-agitator assembly comprises a cage structure 68, a plurality of inner scraper blades 70 and outer scraper blades 72 supported on the cage structure 68 in operable engagement with respective inner and outer sidewalls 32, 34, and inner and outer spiral flights 74,76 supported on the structure 68 adjacent the respective sidewalls 32,34. As shown for example in Figure 1, the cage straddles substantially the entire axial length of drum 30 to permit maximum contact between the scraper blades 70,72 and the sidewalls 32, 34. A spider 78 attached to the upper end of the cage structure 68 secures the assembly 16 to the support member 26, and bearings 80 permit rotation of the assembly 16 about an axis concentric to the axis rotation of the heat transfer unit 14.The scraper-agitator assembly is driven by a right angle gear motor 82 which is coupled to the spider 78 by a belt and pulley assembly 84. A similar drive (not shown) is provided for the heat transfer unit 14, though it is to be understood that in preferred embodiments the scraper agitator assembly 16 is rotated in a direction opposite to that of the heat transfer unit 14. For example, the motor 82 rotates the scraper agitator assembly 16 in a counterclockwise direction as viewed in Figure 2, and accordingly, the drive for the heat transfer unit 14 operates to rotate the latter in a clockwise direction as viewed in the same Figure 2.

The processor is shown in its normal operating position in Figure 1. It is contemplated, however, that the support member 26 may be pivoted in a counterclockwise direction about the axis 27 through an angle sufficient to fully remove the heat transfer unit 14 and the scraper agitator assembly 16 from the kettle 18. By this construction, the processor 10 may be easily moved from one kettle 18 to another without special manipulation of the kettles.

Considering the scraper blades 70, 72 in more detail, it can be seen in Figure 2 only three inner scraper blades 70 are provided, whereas there are six outer scraper blades 72. The reason for the larger number of outer scraper blades 72 is to compensate for the greater surface area presented by the outer sidewall 34. The blades 70, 72 themselves are constructed of conventional material and may be of known design, and are, of course, biased in a suited manner against their respective sidewalls 32, 34 as is the practice in the construction of scraped surface heat exchangers.

As shown in Figure 4 the spiral flights 74,76 are of "opposite hand". That is to say, when the flights 74, 76 are rotated in the same direction, they create countermoving flows within the material contained in the kettle 18. In the preferred embodiment, the flights 74,76 are arranged to create an upward flow outboard of the drum 30 and a downward flow inboard of the drum. Such arrangement is believed to optimize the agitator effect of the assembly 16.

In preferred forms, the kettle, 18 is complementally sized with respect to the drum 30 such that substantially the same volume of material is contained outboard of the drum 30 as inboard. This relationship between the drum 30 and the kettle 18 can be expressed approximately as: R2 = < x R1, where R1 is the nominal radius of the drum 30, and R2 is the radius of the kettle 18. Of course, as shown in Figure 1,the ideal operating position of the procesor is with the drum 30 concentrically disposed within the kettle 18.

The universal batch processor of the present invention has potential for wide use in the field of food and chemical processing. As explained hereinabove, there exists a need in the industry for an efficient, low cost processor capable of blending, heating and cooling small batches of material without incurring substantial material loss.

For example in the preparation of salad dressing, a starch base may first be prepared in a kettle 18 by utilization of the processor 10, and other ingredients may thereafter be added to the base as desired by the producer. Mixing ofthe ingredients may be accomplished by operating the scraper-agitator assembly 16 without circulating heat transfer fluid through the unit 14. The preparation of the salad dressing can be carried out from start to finish using only a single kettle 18, thereby reducing clean up and handling time.

Further, it is contemplated that a food preparer might utilize the processor 10 in the preparation of a number of different foods contained in various kettles 18. The processor 10 might first be positioned over a kettle of mashed potatoes, next moved to a batch of soup, and finally utilized in preparation of pudding.

Using the preparation of pudding as an example, the scraper agitator assembly is rotated within the kettle 18 to blend the ingredients of the pudding while at the same time heat transfer fluid is circulated through the drum 30 in the manner described to raise the temperature of the pudding ingredients to a desired temperature for the required length of time. Subsequently, chilled water or other fluid may be circulated through the drum 30 in the same manner described to lower the temperature as required for setting the pudding. The improved heat transfer capability of the processor 10 reduces the time at which the mixture is maintained at temperature levels which encourage the growth of bacteria and thus, the overall quality of the food product is significantly improved.

Additionally, the cooling operation of the processor 10 is significantly more efficient than conventional chilling of small batches in refrigerators. Hence, cold storage space can be more advantageously applied in plants utilizing the processor 10.

In accordance with the foregoing, it is clear that the present invention represents a significant improvement over small batch processors heretofore known in the art. The combined blending and heat transfer capabilities of the processor 10 render it highly desirable for use in the preparation of small batches of foods and chemical products.

Claims

1. A universal batch processorfor material contained in a kettle or other vessel, said processor including: a heat transfer element which can be immersed in material contained in a said vessel of suitable size, said element comprising an open-ended, hollowwalled tubular drum presenting inner and outer sidewalls and a closed annular cavity between the sidewalls; a scraper element having scraper blades in operative engagement with said sidewalls externally of said cavity; means for circulating heat exchange fluid through said cavity in the drum; and means for rotating one of said elements relative to the other about the axis of said drum whereby to effect scraping of the inner and outer sidewalls simultaneously.

2. A universal batch processor for liquid and semisolid material, said processor including: an open top vessel adapted to contain an amount of a said material; a heat transfer element adapted to be immersed within a said material when the material is disposed within said vessel, said element comprising an open-ended, hollow-walled tubular drum presenting inner and outer sidewalls and a closed annular cavity between the sidewalls; a scraper element having scraper blades in operative engagement with said sidewalls; means for circulating heat exchange fluid through said cavity in the drum, and means for rotating one of said elements relative to the other about the axis of said drum whereby to effect simultaneously scraping of the sidewalls when the heat transfer element is immersed within said material.

3. A universal batch processor according to claim 1 or 2, comprising an adjustablesupportfor said heat transfer element, said heat transfer element depending from said support with the axis of said drum in a normally upright position.

4. A universal batch processor according to claim 3, said rotating means including a drive for said scraper element operable to rotate the latter in one direction about the upright axis of said drum.

5. A universal batch processor according to claim 4, said rotating means further including a second drive for said heat transfer element operable to rotate the drum about its upright axis in a direction opposite to said one direction.

6. A univeral batch processor according to claim 3,4 or 5, said support including a horizontal pivot to permit selective up and down swinging movement of said elements.

7. A universal batch processor according to any one of the preceding claims, said circulating means including spiral baffles forming a double lead helix extending the full axial length of said annular cavity to define a circuitous flow path therethrough.

8. A universal batch processor according to claim 7; said circulating means further including a header communicating with said channel at the lower end of said cavity for directing heat exchange fluid to and from said flow path.

9. A universal batch processor according to any one of the preceding claims, comprising inner and outer spiral flighting on said scraper element proximal to said inner and outer sidewalls, respectively, and coaxial with said drum, for agitating said material when said scraper element is rotated.

10. A universal batch processor according to claim 9, said inner and outer flighting having opposite hand leads.

11. A universal batch processor according to claim 10, said one direction of rotation being clockwise, said outer flighting having a right hand lead.

12. A unviersal batch processor according to claims 2 and 3, said support including a horizontal pivot to permit selective up and down swinging movement of said heat transfer element, into and out of said vessel.

13. A universal batch processor according to claim 3 when dependent upon claim 2, said support having a locator engageable with said vessel for positioning the drum in coaxial relation to said vessel.

14. A universal batch processor according to claim 13; said vessel and said drum being generally cylindrical, the dimensional relationship between the vessel and drum being R2 = ax R1, where R1, is the nominal radius of said drum, and R2 is the radius of said vessel.

15. A universal batch processor substantially as herein described with reference to the accompanying drawings.