Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
  • A23B2/00—Preservation of foods or foodstuffs, in general
  • A23B2/001—Details of apparatus, e.g. pressure feed valves or for transport, or loading or unloading manipulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B5/00—Drying solid materials or objects by processes not involving the application of heat
  • F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
  • F26B5/06—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum the process involving freezing
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
  • A23B2/00—Preservation of foods or foodstuffs, in general
  • A23B2/90—Preservation of foods or foodstuffs, in general by drying or kilning; Subsequent reconstitution
  • A23B2/92—Freeze drying
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B15/00—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form
  • F26B15/10—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions
  • F26B15/12—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined
  • F26B15/14—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined the objects or batches of materials being carried by trays or racks or receptacles, which may be connected to endless chains or belts
  • F26B15/146—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined the objects or batches of materials being carried by trays or racks or receptacles, which may be connected to endless chains or belts applying multiple superimposed tray conveyors, the materials to be dried being dropped onto subsequent conveyor stretches, e.g. by allowing the trays to tilt at one point
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
  • F26B17/02—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts propelling the materials over stationary surfaces
  • F26B17/04—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts propelling the materials over stationary surfaces the belts being all horizontal or slightly inclined
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
  • F26B25/001—Handling, e.g. loading or unloading arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
  • F26B25/008—Seals, locks, e.g. gas barriers or air curtains, for drying enclosures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B3/00—Drying solid materials or objects by processes involving the application of heat
  • F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
  • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs

Definitions

• This invention relates to a continuous freeze dryer, a hopper for supplying product to the freeze dryer and a method of freeze-drying.
• Products such as food products, may be dried using pure drying systems, which operate at atmospheric pressure and remove moisture by evaporation using heat, or freeze dryers, which operate by freezing a product, lowering the pressure in a vessel, and then removing the ice by sublimation.
• Current freeze drying machines largely fall into the categories of small batch dryers or large and expensive "continuous" dryers.
• Small batch dryers consist of a single vessel into which product is loaded, the dryer is closed and evacuated and temperature is cycled through the drying process. These systems have limited throughput, require a high amount of labour and have relatively high processing costs on a cost per weight of product basis.
• a continuous freeze dryer comprising: a. freeze-drying chamber capable of at least partial evacuation having a continuous conveyor from an inlet to an outlet, wherein the inlet has an inlet valve; and b. a hopper for supplying product to the inlet of the freeze-drying chamber configured to form a sealed coupling with the inlet, wherein the hopper includes a hopper valve allowing the hopper to be sealed and evacuated with a product to be freeze-dried inside, wherein, when the hopper is coupled to the chamber, the inlet valve and hopper valve may both be opened to provide a pathway between the hopper and the chamber whilst the hopper and chamber are maintained in an evacuated condition.
• a hopper for supplying product to a freeze dryer inlet including: a. an external shell; b. an internal shell within the external shell defining a cavity between the shells and including openings in the internal shell creating a fluid transfer path between the interior of the internal shell and the cavity; c. a product port for coupling to an inlet of a freeze dryer to provide a conduit for the supply of product to the freeze dryer; d. an evacuation port for evacuation of the cavity; and e. a hopper valve for opening and closing the product port.
• a continuous freeze-drying method comprising the steps of: a. providing an evacuated freeze-drying chamber having an inlet and an outlet; b. loading product into a hopper; c. coupling the hopper with the inlet of the freeze-drying chamber; d. evacuating the hopper; e. opening a pathway between the hopper and the inlet to allow product to enter the evacuated freeze-drying chamber; and f. conveying the product through and freeze drying the product in the freeze-drying chamber.
• Figure 1 is a cross-sectional side view of a freeze dryer supplied with product by a hopper
• Figure 2 is a cross-section top view of the freeze dryer shown in figure 1;
• Figure 3 is a cross-sectional side view of a hopper positioned above a freeze dryer inlet prior to coupling;
• Figure 4 is a cross-sectional side view of a hopper coupled to a freeze dryer inlet
• Figure 5 is a cross-sectional side view of a hopper coupled to a freeze dryer inlet with the freeze dryer inlet valve open;
• Figure 6 is a cross-sectional side view of a hopper coupled to a freeze dryer inlet with the freeze dryer inlet valve and hopper cone valve open.
• Figure 1 illustrates a freeze dryer including a chamber 1 with a hopper 2 coupled to it to supply a product 3 to the freeze dryer and a receptacle 4 for receiving processed product.
• Product entering the freeze dryer is distributed onto a tray 5 by a rotary feeder 6 as the tray passes under it.
• a number of trays are provided on each level depending upon the size of the chamber.
• the trays are sequentially moved from the top to the bottom as illustrated by the arrows and at the bottom the tray 8 is tipped to release product via outlet 9 into receptacle 4 when butterfly valve 10 is open. Tray 8 is then moved to the top tray position (tray 5).
• Radiating elements 7, in this case in the form of electrical resistances elements, are provided above each tray to heat the product on each tray.
• Heating is controlled to decrease heating from the top tray to the bottom tray as the product heats and moisture is removed from the product.
• a number of condensers 11 are provided in bays 12 within chamber 1.
• the condensers trap water vapour removed from the product as ice which must be periodically removed, typically when a layer of ice about 3-5 mm thick forms on the surface of a condenser.
• a screen 13 moves across a bay 12 during defrosting. The condenser is then heated and condensate and defrost water is then conveyed out of the chamber. After defrosting a condenser, the screen 13 may be moved to the next bay 12 to defrost the next condenser.
• FIG 3 a side cross-sectional view of the hopper 2 and chamber inlet 14 are shown. All components have circular horizontal cross sections.
• the hopper 2 is seen to be formed by an external shell 15 supporting a spaced apart internal shell 16 defining a cavity 17 between the walls of the shells.
• the double wall construction provides insulation between the frozen product within the hopper and the external ambient temperature, reducing frosting and condensation, which may pose a biological hazard.
• An opening at one end of the inner shell forms a product port 20 for supplying product to the chamber inlet 14.
• the inner shell 16 has a number of openings 18 (enlarged for illustration) creating a fluid transfer path between the interior of the internal shell 16 and the cavity 17.
• An annular opening 19 forms an evacuation port for evacuation of fluid from the hopper - fluid within internal shell 16 passes through openings 18 to the cavity 17 and then out through the annular opening 19 to evacuation port 24.
• a hopper valve in the form of cone valve 21 is provided which may be closed to retain product within the hopper or opened to allow product to flow into the chamber inlet 14.
• the chamber inlet 14 includes an inlet valve 22 that may be raised and lowered by a linear actuator, in this case a ram 23. In the closed position inlet valve 22 provides an airtight seal to chamber 1. In the open position inlet valve 22 is raised (into the hopper) a sufficient height to allow product to flow from the hopper 2 into the chamber inlet 14.
• FIG 3 shows the chamber inlet 14 sealed by inlet valve 22 with the hopper 2 positioned above and apart from hopper 2.
• Hopper 2 has been previously loaded with frozen product and cone valve 21 closed.
• Hopper 2 is then lowered onto inlet 14 and coupled thereto as shown in Figure 4.
• Hopper 2 is coupled to the inlet 14 so that annular opening 19 is aligned with evacuation port 24 and product port 20 is aligned with the product inlet 14.
• the hopper is then evacuated via evacuation port 24 which draws fluid within internal shell 16 through openings 18 to the intermediate cavity 17 and then out through the annular opening 19 to evacuation port 24.
• the hopper may be evacuated to a pressure close to or the same as the pressure within the chamber, preferably 2 mbar or less. This ensures that there is no significant variation of the conditions within the chamber 1 during loading which may adversely affect product processing and also minimizes the energy required and handling.
• linear actuator 23 is extended to initially open the inlet valve 22 as shown in Figure 5.
• the liner actuator is further extended to the position shown in Figure 6 to open the cone valve 21 too and is raised high enough allow product to be supplied to the freeze dryer via the chamber inlet 14.
• product supplied via inlet 14 is evenly distributed by feeder 6 over the top tray.
• the chamber is at least partially evacuated in use, preferably to 2 mbar or less.
• Each tray is heated by radiating elements 7 positioned above the trays of each level to provide required heating.
• the radiating elements are controlled to create a temperature gradient that decreases from the top to the bottom of the chamber 1.
• the trays are continuously moved down from the top to the bottom.
• the bottom tray 8 is ready to be emptied it is tilted so that product may be supplied to the chamber outlet 9. Once free of product the bottom tray 8 moves to the top to become the new top tray 5.
• an alternative form of conveyor may be employed to convey the product from the inlet to the outlet through the chamber.
• a receptacle 4 is coupled to outlet 9 and evacuated to a pressure of about 2 mbar.
• Butterfly valve is then opened (the position shown in dashed line) so that product supplied from the bottom tray 8 may pass through outlet 9 into receptacle 4.
• a trolley 25 may be provided within the receptacle to collect processed product and when the trolley 25 is full butterfly valve 10 may be closed, the receptacle 4 repressurised, a door of the receptacle 4 opened and trolley 25 removed and replaced with an empty trolley.
• High throughput - continuous operation avoids delays in pressurising/ unloading/loading/depressurising each load.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Molecular Biology (AREA)
• Health & Medical Sciences (AREA)
• Polymers & Plastics (AREA)
• Food Science & Technology (AREA)
• Chemical & Material Sciences (AREA)
• Zoology (AREA)
• Wood Science & Technology (AREA)
• Microbiology (AREA)
• Drying Of Solid Materials (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70462472

Family Applications (1)

Country Status (11)

Cited By (1)

Families Citing this family (4)

Citations (7)

Family Cites Families (15)

• 2019
  • 2019-10-10 US US17/289,505 patent/US20210386100A1/en not_active Abandoned
  • 2019-10-10 KR KR1020217016301A patent/KR20210084578A/ko not_active Withdrawn
  • 2019-10-10 JP JP2021548499A patent/JP2022509481A/ja active Pending
  • 2019-10-10 MX MX2021004831A patent/MX2021004831A/es unknown
  • 2019-10-10 CA CA3118075A patent/CA3118075A1/en active Pending
  • 2019-10-10 AU AU2019373054A patent/AU2019373054A1/en not_active Abandoned
  • 2019-10-10 CN CN201980072187.7A patent/CN112955708A/zh active Pending
  • 2019-10-10 SG SG11202104361TA patent/SG11202104361TA/en unknown
  • 2019-10-10 EP EP19880225.8A patent/EP3874217A4/en not_active Withdrawn
  • 2019-10-10 WO PCT/NZ2019/050133 patent/WO2020091607A1/en not_active Ceased
• 2021
  • 2021-05-27 ZA ZA2021/03632A patent/ZA202103632B/en unknown

Patent Citations (7)

Non-Patent Citations (1)

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