WO2016191799A1

WO2016191799A1 - Freeze drying improvements

Info

Publication number: WO2016191799A1
Application number: PCT/AU2016/000191
Authority: WO
Inventors: Allan MOCK; Neville MOCK
Original assignee: Freeze Dry Industries Pty Ltd; Mock Enterprises Pty Ltd
Priority date: 2015-06-04
Filing date: 2016-06-03
Publication date: 2016-12-08

Abstract

An apparatus for freeze drying a product comprising a heat exchanger to recycle and enable reuse of heat generated during operation.

Description

Freeze drying improvements

Background of the invention:

Drying is traditionally defined as that unit operation which converts a liquid, solid or semi-solid feed material into a solid product of significantly lower moisture content. In most cases, drying involves the application of thermal energy, which causes water to evaporate into the vapour phase. Freeze drying provides an exception to this definition, since this process is carried out below the triple point, and water vapour is formed directly through the sublimation of ice. The requirements of thermal energy, phase change and a solid final product distinguish this operation from mechanical dewatering, evaporation, extractive distillation, adsorption and osmotic dewatering.

Drying is a complex process involving simultaneous coupled, transient heat, mass and momentum transport. These are often accompanied by chemical or biochemical reactions and phase transformations, such as glass transition and crystallization, along with shrinkage.

Foods are dried commercially, starting either from their natural state (e.g. vegetables, fruits, milk, spices, grains) or after processing (e.g. instant coffee, whey, soup mixes, non-dairy creamers). The production of a processed food may sometimes involve drying at several stages in the operation. In some cases, pre-treatment of the food product may be necessary prior to drying. In addition to preserving the product and extending its shelf life, drying may be carried out to accomplish one or more of the following additional objectives:

• Obtain desired physical form (e.g. powder, flakes, granules);

• Obtain desired colour, flavor or texture;

• Reduce volume or weight for transportation;

• Produce new products which would not otherwise be feasible.

Drying is important to the food industry as it consumes up to 10% of the total energy used in that sector. The selection of a dryer is, however, driven more by product quality considerations than be energy saving potential. Environmental impact and safety of operation are additional factors which influence the selection of a drying system. While over 200 different types of dryer have found various applications in industry, only about 20 basic types and their variants are commonly used in practice. This wide range of dryers is due to the diverse physical forms of the products to be dried, the production rates desired, and the quality constraints on the dried product. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

Summary of the invention:

In one aspect of the invention there is provided an apparatus for freeze drying a product comprising a heat exchanger to recycle and enable reuse of heat generated during operation. In another aspect, there is provided an apparatus for freeze drying a product comprising at least one sensor to sense a freeze drying parameter and a heat exchanger to recycle and enable reuse of heat generated during operation. In another aspect of the invention there is provided an apparatus for freeze drying a product comprising a computing device to receive information about a freeze drying process and compute and report one or more pieces of information about the process. The invention also comprises a rack for a freeze drying apparatus comprising a conduit for flow of a heat transfer medium.

In another aspect of the invention, there is provided a method of freeze drying a product comprising recycling heat generated during operation. In another aspect of the invention, there is a method of freeze drying a product comprising monitoring an operational parameter and automatically adjusting operation to maintain operation within a pre-set guideline for that parameter. In one aspect there is provided a method of freeze drying a product comprising maintaining a heat transfer medium with in a defined temperature range so as to reduce energy requirements.

In another aspect of the invention, there is provided a computerised method of freeze drying a product comprising: receiving information in relation to one or more critical control points and creating a batch recipe from the at least one critical control point. In another aspect there is provided a non-transitory computer-readable medium storing instructions for execution by a processor to control a freeze dryer, the instructions including: code to enable receipt of information relating to one or more critical control points; code to enable storage of the critical control point information; code to computationally create a batch recipe from the at least one critical control point.

In another aspect, the invention provides a computerised method of freeze drying a product comprising: receiving information in relation to one or more critical control points; creating a batch recipe from the at least one critical control point; computing a batch finish point and reporting the batch finish point. In yet another aspect, the invention provides a non-transitory computer-readable medium storing instructions for execution by a processor to control a freeze dryer, the instructions including: code to enable receipt of information relating to one or more critical control points; code to enable storage of the critical control point information; code to computationally create a batch recipe from the at least one critical control point; and code to compute a batch finish point.

In one aspect of the invention, there is provided an apparatus for freeze drying comprising a heat exchanger recycle heat generated during operation. In some aspects, the invention provides a method of freeze drying a product comprising recycling heat generated during operation. The heat exchanger may be of any suitable type. In some embodiments it comprises a heat-carrying liquid which may optionally be an oil and preferably a food grade suitable oil. In some embodiments the recycled heat is used to assist in the drying process.

In another aspect of the invention, there is provided a method of freeze drying a product comprising monitoring an operational parameter and automatically adjusting operation to maintain operation within a pre-set guideline for that parameter. Pre-set guidelines may be of any suitable type. In some embodiments they comprise one or more environmental or system parameters, for example for temperature, pressure, humidity, etc. In some embodiments the pre-set guidelines comprise one or more aspects of operation such as heat exchange fluid speed, fan speed, vacuum, suction speed, etc. In some embodiments, the pre-set guidelines are specifically set depending on one or more characteristics of the product to be freeze dried.

Throughout this specification (including any claims which follow), unless the context requires otherwise, the word 'comprise', and variations such as 'comprises' and 'comprising', will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Brief description of the drawings:

Figure 1 is an abbreviated process flow chart according to one aspect of the invention.

Figure 2 is a schematic showing heat reclaimed and capacity coordination across the batch process in some embodiments of the invention. Figure 3 is a combination exploded / cut away view of a rack according to some embodiments of the invention.

Figure 4 depicts example oil banks according to the embodiments of Figure 3. Figure 5 is a more detailed view of the aluminium plates incorporated into Figure 3. Figure 6 is a more detailed view of the tube welding element of Figure 3. Figure 7 is a more detailed view of the tube bending element of Figure 3. Figures 8 and 9 shows the direction of oil flow in Figure 3.

Figure 10 is a more detailed view of the inlet and associated hardware of Figure 3.

Figure 11 is a more detailed view of the outlet and associated hardware of Figure 3. Figures 12 and 13 are cut away views of the rack of Figure 3.

Figures 14 to 18 depict further details of an example rack according to the invention.

Figures 19 to 22 depict various views and aspects of a freeze dry tank according to the invention.

Figures 23 to 32 depict various views and detailed aspects of the vessel of the freeze dry tank of Figures 19 to 22.

Figure 33 is a schematic of an example ice condenser according to the invention.

Figure 34 depicts an example flow chart in relation to a Freeze Dryer Automation system according to the invention.

Figures 35-37 depict example graphs showing operation of a freeze dry apparatus according to the invention.

Figure 38 depicts sample flow charts for starting and ending heat cycles according to certain embodiments of the invention. Figures 39A-42 depict example user interfaces for control of a system according to the invention.

Figure 43 shows front and rear cut away elevated views of an example freeze drier according to the invention. Figure 44 shows another example freeze drier according to the invention and an example set of racks.

Figure 45 is an example batch report according to the invention.

Figure 46 is an example batch finish point graph according to the invention.

Figure 47 is a graph depicting the relationship between four vessel temperature probes during the batch process.

Figure 48 is an example energy report according to the invention.

Detailed description of exemplary embodiments:

It is convenient to describe the invention herein in relation to particularly preferred

embodiments. However, the invention is applicable to a wide range of implementations and it is to be appreciated that other constructions and arrangements are also considered as falling within the scope of the invention. Various modifications, alterations, variations and or additions to the construction and arrangements described herein are also considered as falling within the ambit and scope of the present invention. In certain embodiments, the invention provides a freeze drying unit with benefits comprising one or more of:

• Designed and built to be a low energy demand machine by using recycled heat generated from all components. In some embodiments 20-90% heat, preferably 40-80%, more preferably 70-80% of heat is recycled. In some embodiments 80% of heat is recycled. · Computer controlled system governed by product type with automated adjustable

parameters. • Cost effective, economical system that can utilise low value or even otherwise waste product. Meaning that the freeze dryers are easy and low cost to run therefore creating a return on investment from low value produce.

• The system program is calibrated to the unique product specifics therefore is governed by the product or raw material. In turn the system modifies the settings via a series of code and algorithms, during the production process according to the performance

characteristics.

• Computer system; governed by product lyophilisation, self diagnostic, adjustable

parameters, maximum heat barrier, sensor keys and constant monitoring of heat, vacuum and suction pressure.

Unlike the Freeze Dryer of the invention, machines that are not driven by the suction pressure of the material have a much higher failure rate and less predictable outcomes.

The device of the invention may comprise self diagnosis of various aspects, for example the suction pressure to continuously react and adjust critical control points ( CCP's ) to ensure product integrity and desired outcome which include yield, colour , shape, size, nutrition and enzymes..

The device of the invention has inbuilt versatility to modify itself and cope with a vast range of raw materials. Previous freeze dryers tend to be hard, fast and energy sapping but very effective in taking the moisture out of a product. In contrast, the device of the invention is low temperature and slower but focuses on the absolute quality of the product.

The skilled addressee will appreciate that a wide variety of implementations of the invention have a range of capacities, temperatures and times taken per run. As an example, in some embodiments, there is provided a dryer with a 400 kg capacity at a maximum temperature of 50° C, in another example embodiment, there is provided a 900kg capacity up to 50° C for 120 hours. In one preferred embodiment, there is provided a dryer with 960kg capacity up to 55° C and for 100 hours. The focus on lower temperatures and slower run times of the current invention is for example implemented with a system control point that ensures that the temperature cannot exceed a particular set high temperature. In some embodiments this may be chosen based on equipment specifications, in others it may for example be 50° C. Some embodiments set an upper limit based on the "pasteurisation " point of 65° C. This upper limit is in designed to ensure maximum product integrity (colour, flavour, nutrition, shape, size, texture). Further, according to the present invention, these control settings have been improved to "prove" any maximum temp set point (eg. 28° C) depending upon the product and end user requirements. Competitor products promote and focus on so called productivity or speed of batch through-put. To do this they must increase heat to reduce batch time but also increase energy usage and consumption.

Example water content, batch times and energy cost for a range of fruit products according to the invention.

The reader should note that the above batch times are estimates as the water sublimation does not occur perfectly over the batch time. This is due to "diminishing returns" as the water content reduces over time then the rate of sublimation must be less.

In contrast, typical competitor freeze dryers cost in the range of $250 - 400 (eg. $360) in energy per batch even on a 24 hour cycle.

Furthermore the unique Finish Point data elements of the invention (for example as implemented using the FP graph and vessel temperature probes) and system intelligence impact energy consumption dramatically.

Other systems must use more energy to compensate for the rate of lyophilisation in their processes. If they don't then their system becomes unbalanced thus high risk of a ruined batch. The design and control of the system of the invention is calibrated to best utilise available energy without any extra being drawn from the power supply.

The rack of the device of the invention is specifically designed to be simply constructed and to allow for even heat transfer through multiple identical circuits for which the heat transfer medium (eg. oil) can flow with maximum efficiency. Heat being reclaimed from the refrigeration system. Even heat transfer is critical for simultaneous drying of all the raw material product within the batch. This method is superior to pure electrical heating as it demands less power. Rack capacity equals the refrigeration capacity.

The Ice Condenser of the device of the invention is specifically designed to allow open air flow at produce end. This formula minimises total ice formation and thickness to simplify the time and energy requirements to defrost the resultant ice blocks between batches. Ice condenser capacity equals rack capacity.

The refrigeration system of the invention is specifically designed to run surface temperature of the evaporator/ ice condenser at less than minus 40 degrees C. This being the coldest point of the system where water vapour will migrate and reform as ice.

By reclaiming heat from the refrigeration system, via a multi plate heat exchanger, a heat transfer medium such as silicon oil is heated and circulated throughout the racking system construction. This invention gently heats the product to enhance lyophilisation at a rate in balance with all other system components. This means that the Silicon oil is continuously circulated throughout the process with heat only being added as required and in accordance with the computer program settings. Typically other Freeze Dryers turn their heat on and off, thus using a large amount of energy to recover or reset. Oil cools very quickly so requires a lot of new energy to reheat. The present invention therefore is much more energy efficient by keeping oil temperatures stable and sensitive to the variables inherent in the freeze drying process.

In some implementations of the invention, the fan speed controller is an important aspect of the heat reclaiming system, in some embodiments, the freeze dryer will not operate without the fan speed controller to ensure maximum performance. This system protocol limits the real risks of overheating which in turn may ruin the product batch and/or be very energy inefficient.

The condenser fan speed controller ensures optimum head pressure essential to the optimum heat reclaim goals.

In some embodiments, silicon oil 50cs is used because of its viscosity and stability through the large temperature variants of minus 50°C to plus 70°C. In some embodiments a maximum temperature set point is set at 65°C. It is also the accepted standard for the "best food grade" industry. Other fluids may be used, for example, glycol may be used. Or other such fluids may be used as an alternative fluid as a backup and for contingencies.

In some preferred embodiments, glycol is used for reasons including: 1. It can be further diluted and bleached;

2. It is cheaper and more readily available than silicon;

3. It is thinner and therefore easier to pump and requires less energy.

In some embodiments, the system or apparatus of the invention comprises pressure sensors to enable sensing the pressure of the fluid and adjustment as required.

The software system and control panel sets the suction pressure, vacuum pressure and heat. These key variables are set and maintained within the desired values and react or alarm to maintain consistent outcomes.

Some aspects of the invention provide dashboard displays, pages and reports. These reports are machine generated from collected data. In some embodiments, a system according to the invention can create batch recipes from the input variables. In another aspect the system provides a finish point graph / report. Such a graph / report allows a user to "see" the perfect completion of a batch at the intersection point. This means that rather than predict that product batch will be ready in 96 hours, a user can prove the completion by using and studying the FP data. This produces advantages such as greater efficiency for example by entering the FP to the factory calendar and recording the batch knowledge for future same product runs.

In some aspects, the system provides temperature probe live data and report. In some embodiments, an optimum finish of the product is when the probes equalise in temperature up to the set point maximum. For example the temperatures may raise from for example - 25 to + 32 degrees C. However if any of the 4 probes are read less than the others then the user knows that there will be "soggy" spots on the trays and that the batch must continue on until the vessel trays/regions are all the same. Some aspects provide at least one energy monitor to enable reports and readings for the user to best manage and improve consumption, costs and emissions.

Figure 39A depicts an example dashboard according to one aspect of the invention. This example dashboard has been designed to interface with the Citect SCADA pic system. The dashboard features allow a user to see each dryer live status (which may for example be colour coded) as well as batch progress (in this figure, depicted by a bar) with time to completion and energy monitoring. The freezers and vacuum pump have been included on the dashboard for status monitoring and energy management also. (The reader should note that image 1 is a live capture from an example actual operating model. As the batch is not physically running the data reads as "bad" so can be ignored.) Figure 39B depicts another example dashboard according to the invention and is an example of a colour coded system and manager's dashboard. Important features include colour code status, progress bar displaying time gone and time to completion, energy consumption live reading, and ability to click through from each dryer.

Figure 40B depicts an example page displayed according to one aspect of the invention. This system page loads when a dryer from the dashboard is selected. The dryer actual displays its operational status with live data animation and readings. The Critical Control Points (CCP) are a combination of set points which for example may be entered by a user or computationally created from sensor readings which may be for example live readings. According to the invention herein, a Recipe is a unique formula of CCP's and other information such as the batch time which can be saved in to Reports for retrieval and used for control and performance management.

Some implementations of the invention further provide batch temperature probes. Without being limited in any way, the theory is that the raw materials are dried and thus batch complete, at the point where multiple temperature probes equalise. In some embodiments, there are 4 such probes, but any suitable number can be used, based on such factors as the size of the dryer, the type and amount of material being freeze dried, etc.

In some such embodiments of the system, there are installed probes that return live readings back through the system and record those readings at set intervals in reports. An example is that the batch materials start frozen at minus 20 degrees C; the 4 probes throughout the vessel will then start to read higher temperatures as the drying process continues; it is expected that the probes will read differing temperatures due to product drying rates; once the product reaches the temperature set point maximum (for example 40 degrees C) as proven by the 4 probes, the batch is expected to be finished and all the materials to have been dried consistently. Using this technique adds another layer of intelligence to improve productivity.

The temperature probe data is recorded in reports and provides another measurement of batch time to compare to CCP formula expectations. This data can be computationally utilised to create new recipes, and to create and / or select a recipe appropriate for a new application.

Another feature is that the set, Predicted Finish Point automatically loads to the Calendar in the menu tab. This is an important production management record so that resources can be best managed and allocated. As batch time knowledge improves, machine down time is reduced and the number of batches and output are increased, and more accurate finish times allow for much better staff and resource management. Figure 45 depicts report data for a batch as entered and set by the operator (CCP). It also allows for the batch running time to be recorded as expected and actual (Run Final). This is an important management feature to compare expected time versus actual time.

Figure 46 depicts an example system algorithm that reads the 3 critical variables throughout the batch performance. When the 3 variables intersect the batch has been completed. This report and data attempts to alert management to other strict performance criteria to lock in the knowledge of the finish point of each batch.

Figure 47 is a graph showing the relationship between the 4 vessel temperature probes during the batch process. A management alert is programmed in at the equalising point.

Figure 48 is an energy report and is important to the constant improvement of batch performance to reduce energy costs and carbon emissions. Energy meter readings are set throughout the system to test for good, bad or normal energy consumption levels and address those relevant areas of improvement.

Example 1 In one example implementation of the invention, there is provided a freeze dryer ("LTFD1000") designed to condense l Olitres of water per hour for a 5-7 day period. (The time period will vary depending on the product and end-use requirements.) For example the 1000 is intended to sublimate (vaporise and re-condense) 900 litres of water, frozen as ice, from the product to the "ice condenser" during the drying period. This cycle time provides for production efficiencies such as planning around production, loading, unloading and defrosting within that drying cycle.

The freeze dryer of the invention has many design features such as low temperature drying and versatile advanced computer control. Low temperature drying is an integral part of the drying procedure as it aims to retain the integrity of the product such as physical and nutritional characteristics. Computer control has the capabilities of fully automatic operation

complimented by detailed data logging and computation of critical points and recipes. The manual mode has fully adjustable parameters which allows for versatile testing and

experimentation which is essential when drying "new" products. The data recording is an essential for the experimental process as an analytical tool. Several efficiencies have been designed into the 1000 such as an automatic heating system. This heating system uses heat generated by its own refrigeration as a renewable energy source. In some embodiments of the invention, the fully automated, computerised mode of the invention analyses feedback data and creates one or more critical control points and may thereafter create and store a recipe for a particular type of product to be freeze dried.

In some embodiments of the invention, there is provided a reporting module to provide information to a user in relation to one or more operational aspects. In some embodiments this module comprises a graphical user interface and in some embodiments it provides information in relation to one or more of temperature, vacuum pressure, suction pressure, energy use, predicted operational requirements at one or more locations in a system according to the invention, and preferably information in relation to interactions between one or more of such parameters.

Example 2

In another example implementation, there is provided a freeze drying apparatus with the following characteristics:

Chamber

The vessel (or chamber) is constructed of stainless steel approximately 5 meters long and an overall height of 2.7 meters including the refrigeration. It has a single full size door at one end and each end has a 200mm viewing port allowing for observation of the product and the internal ice condenser during the freeze drying (lyophilization) process.

Refrigeration system

Refrigeration is via a 2 stage low temperature 9.2kW Semi-hermetic Bitzer compressor using R404A low temperature refrigerant. The internal evaporator (ice condenser) condenses approximately 10 litres of water per hour during the normal drying cycle.

Drying rack

Racking system is constructed of aluminium tubing with flexible hosing and quick release couplings. This is integral to the heating system as heated oil can be circulated throughout the rack benefited by the excellent even heat transfer characteristics. The rack accommodates 60 stainless steel food trays which are easily slid into place for freezing and drying.

Control system

Operation of the apparatus is controlled via a computer system with fully automatic or fully manual options. The system is also an advanced analytical tool that can be used for singular or multiple dryers. Parameters are easily set to specific products or custom requirements. The programme also incorporates a self fault diagnostic system. In the event of a fault (eg mains power failure) notification of faults are audible, visual or sent to remote location such as a mobile phone or pc.

Vacuum system

An Italian Brand Pedro Gil 2 stage high vacuum pump is connected to the vacuum chambers via heavy duty PVC lines. Incorporated in the vacuum system is a pneumatic safety actuator that ensures vacuum is contained in the event of mains power failure.

Example Benefits

The freeze dryer of the invention is a low temperature freeze drying unit specifically designed for freeze drying food products where retaining the integrity (shape & nutrition) of the product is essential. This is achieved by a "soft" low temperature, highly efficient drying process. Most of the heat required during the drying process is utilised from reclaimed refrigeration heat. Only a "boost" or final heat is required at the end of the drying cycle which is provided by

thermostatically controlled 4kW electric element.

This efficient use of heating creates a total power requirement of 20 amperes.

The unit is designed for separate freezing of product in a modular racking system. This provides for efficient processing scheduling as one batch can be drying while another is being processed/frozen. (A second drying rack and set of trays not included) This design also allows for multiple freeze dryers to be serviced by a single freezer.

All components such as refrigeration, oil system and electrical controls are contained within a single compact framework located on top of the chamber. This allows for one single fully contained "plug in" unit that is easily transportable and commissioned.

Other requirements recommended - (*compulsory)

· *Freezer

• Trolley for transferring rack between freezer and dryer/s

• Second drying rack and set of trays

• Defrosting equipment such as fans or water.

• High volume vacuum pump for initial pump down

· Compressed air supply Specifications:

Chamber 304 stainless steel

Overall height 2750mm

Overall length 5400 to 5500mm

Overall width 1850mm

Weight 4 tonne

Food Trays 304 stainless steel 2380 to 2400mm x 545 to 550mm x 20mm

No of Trays 60 to 64 (1 set)

Total drying area of trays 79 to 84 sq m, preferably 83.2

Heating Medium Silicon oil

Oil Heating Reclaimed refrigeration heat

Boost Oil Heating 4kW electric

Ice condenser Copper tube construction, -60 deg C, 1000kgs ice capacity

Ice condensing 10 litres per hour

Defrost *Optional

Power Requirements <20Amps, 240V, 50Hz

Optional Other Requirements Rack trolley system, Freezer, Second set of food trays

Example 3

Freeze Drying Plum puree

Prior to receiving the fruit it must be put it through a process that removes the stones or pips and get the stock in to a form that can be managed and put into the freeze drying trays. This puree form is chilled to zero degrees (not frozen) to enable preservation of the fruit nutritional elements and handling. An example batch for a particular experiment may use approximately 400 kilos of fruit being separated into 200 kilos of green fruit and 200 kilos of ripened fruit.

Software according to the invention can record batch performance and allow an operator to record, analyse and compare production specifics for future knowledge and decision making. For example information on variables such as the following may be obtained and recorded: heat, time, quantity and maturity as measured by the Brix scale ( sugar content = level of ripeness).

In some embodiments, a Freeze Drying system according to the invention is able to be modified by the user based on their unique needs and experience.

Example 4

The operation of the batch process is governed by the calibrations of product type with an automated self diagnostic system to ensure maximum performance and quality results.

Rack:

Made of aluminium for best heat transference

Multiple identical oil feed manifold for even heat distribution

Flexible, manual movement of the multiple axle

Maximise product shelf area

Self cleaning ability

Trays stainless steel to match food handling standards

Ice Condenser:

Condensable ice capability equalling produce load

Multiple identical circuits for even ice condensation

Minimise ice production thickness for ease of defrost

Open face for easy vapour flow and defrost

All welds situated on face for access and servicing Electronic tx valves for precise operation

Copper piping

Vessel:

Must be vacuum tight = able to achieve vacuum of > 1 millibar pressure

Large accessible door for racks system

Draw for defrost

Window for view of ice condensation and product

Stainless steel

Refrigeration:

Low temperature capacity to -60 degrees

Two stage compressor

Heat reclaim through multi plate heater

Free heat to heat the silicone oil as the heat transfer medium to supply heat to the racking system

Pressure sensor condenser fan speed controller to compensate for the heat reclaim operation

Suction pressure control monitoring which is governed by the rate vapour is released from the product while under vacuum pressure.

It will be appreciated by the skilled addressee that in some embodiments, the system of the invention will work in conjunction with or comprise a Supervisory Control and Data Acquisition (SCADA) capability. Whilst the CitectSCADA is used as an example in this document, the skilled addressee will appreciate that any suitable SCADA will do.

CitectSCADA:

Self diagnostic automation system that maintains batch controls and limits per the set parameters

Main control points that are variables: suction pressure, vacuum, heat... Includes detailed analysis of varying parameter set points

Allows for the monitoring and control of multiple FD units in the one facility

Has a remote access ability for maintenance, control, fault diagnosis and support.

The operator is able to enter set points for production batches into the CitectSCADA system and initiate or change operational modes of the plant equipment. Process and control variables may be updated to provide near real-time information such as vacuum pressure and system energy consumption levels.

The CitectSCADA system may also generate audible and visual alarms for plant status that requires operator intervention or acknowledgement. Security controls may be implemented such that users with the required privileges may acknowledge, reset, save set points and perform other actions that will affect the operation of plant equipment.

Example 5

Rack:

Made of aluminium for best heat transference

Multiple identical oil feed manifold for even heat distribution

Flexible, manual movement of the multiple axle

Maximise product shelf area

Self cleaning ability

Trays stainless steel to match food handling standards

Ice Condenser:

Condensable ice capability equalling produce load

Multiple identical circuits for even ice condensation

Minimise ice production thickness for ease of defrost

Open face for easy vapour flow and defrost All welds situated on face for access and servicing

Electronic tx valves for precise operation

Copper piping

Vessel:

Must be vacuum tight = able to achieve vacuum of > 1 millibar pressure

Large accessable door for racks system

Draw for defrost

Window for view of ice condensation and product

Stainless steel

Refrigeration:

Low temperature capacity to -60 degrees

Two stage compressor

Heat reclaim through multi plate heater

CitectSCADA :

Self diagnostic, automation system that maintains batch controls and limits per the set parameters

Main control points that are variables: suction pressure, vacuum, heat...

Includes detailed analysis of varying parameter set points

Allows for the monitoring and control of multiple FD units in the one facility

Has a remote access ability for maintenance, control, fault diagnosis and support See other system notes per attachments in previous email.

The CitectSCADA system may also generate audible and visual alarms for plant status that requires operator intervention or acknowledgement. Security controls may be implemented such that users with the required privileges may acknowledge, reset, save set points and perform other actions that will affect the operation of plant equipment. Example 6

Figure 34 depicts an example flow chart in relation to a Freeze Dryer Automation system according to the invention. The FD settings are recorded then monitored per the graphs to show trends and timings of the highs and lows in the process. This knowledge can then be cross checked against the final results to learn how each affected the results.

The machine operating system has a reporting function that allows a user to track and graph the above variables. This in turn allows the user to monitor the batch in progress, measure the results and compare to expectations.

PLC interfaced with touch screen control panel. Screen includes graphic overview of freeze drying system. The automated system will increase or reduce energy to govern sublimation pressure to pre-set parameters.

Self diagnostic automation system that maintains batch controls and limits per the set parameters. The main control points that are variables: suction pressure, vacuum, heat.

Includes detailed analysis of varying parameter set points. Allows for the monitoring and control of multiple FD units in the one facility. Has a remote access ability for maintenance, control, fault diagnosis and support.

Example 7

The system program is calibrated to the unique product specifics therefore is governed by the product or raw material. In turn the system modifies the settings via a series of code and algorithms , during the production process according to the performance characteristics. This is known as the rate of lyophilisation.

Computer system; governed by product lyophilisation, self diagnostic, adjustable parameters, maximum heat barrier, sensor keys and constant monitoring of heat, vacuum and suction pressure.

PLC interfaced with touch screen control panel. Screen includes graphic overview of freeze drying system . Automated system will ramp/reduce energy to govern sublimation pressure to pre-set parameters.

15 x 15-step recipe programming capacity, 250 batch storage, software for data retrieval and analysis. In-built modem allows remote access for monitoring and service

Computer control has the capabilities of fully automatic or fully manual operation complimented by detailed data logging. The manual mode has fully adjustable parameters which allows for versatile testing and experimentation which is essential when drying "new" products. The data recording is an essential for the experimental process as an analytical tool. Several efficiencies have been designed into the 1000 such as an automatic heating system. This heating system uses heat generated by its own refrigeration as a renewable energy source.

These FD settings are recorded then monitored per the graphs to show trends and timings of the highs and lows in the process. This knowledge can then be cross checked against the final results to learn how each affected the results. Depending on the experiment intention a user can constantly improve sets of inputs in line with the historical outcomes to better predict process and batch results . These details will be recorded in online application that has been specifically designed to support, record and house experimentation criteria, documentation and findings.

Each product and batch is subject to the expectations of the customer. Depending on those expectations the user must alter the settings and scope of the machine to coordinate with the hypothesis. A user may make assumptions and experiment accordingly to learn what then happens to that particular product given the variables of time, temperature, brix scale, maturity with desired results ranging from visual integrity, yield, volume, moisture content, colour, weight, taste, enzyme content, nutritional values and costs of production. In some embodiments the machine operating system has a reporting function that allows a user to track and graph the above variables. This in turn allows a user to monitor the batch in progress , measure the results and compare to expectations. The user's new knowledge is then kept in a reporting system so that the user can demonstrate the results to customers and in turn keep appropriate records of activities.

Input/output (I/O) virtualization is a methodology to simplify management, lower costs and improve performance of servers in enterprise environments. I/O virtualization environments are created by abstracting the upper layer protocols from the physical connections.

The technology enables one physical adapter card to appear as multiple virtual network interface cards (vNICs) and virtual host bus adapters (vHBAs). Virtual NICs and HBAs function as conventional NICs and HBAs, and are designed to be compatible with existing operating systems, hypervisors, and applications. To networking resources (LANs and SANs), they appear as normal cards.

In the physical view, virtual I/O replaces a server's multiple I/O cables with a single cable that provides a shared transport for all network and storage connections. That cable (or commonly two cables for redundancy) connects to an external device, which then provides connections to the data center networks.

Example 8

The following is an example functional design for a system according to the invention. Hardware

PLC

Part Number QTY Description

TM221 CE24T 1 PLC CPU (14) Inputs ( 10) Outputs

TM3TI4 1 PLC analog Input Card 16 bit resolution

TM3XTYS4 1 ¹ Tesys Motor Start Control Card

TM3AQ2 1 Analogue Output Card

Motor Contactors Part Number QTY Description

LUB320/LUB120 j 2 Tesys U Power Base

LUCCXXBL 2 Tesys U Control Unit

LU9R1 C 2 Tesys U Pre Made Wiring cable

General Electrical

Part Number QTY Description

RPZF? 10 Relay Base

RPM ? 2 Plug in relay

ABL4RSm24100 2 24volt Power Supply 5A

Circuit Breakers

Terminals

Ducting

Digital Sensors

Part Number QTY Description

Oil Differential Pressure Swi Compressor High Pressure Compressor Low Pressure

Analogue Sensors

Part Number QTY Description

2 Temperature Sensor 4 20ma

1 Vacuum Sensor 4 .20ma

Cooling Controls Part Number QTY ; Description

Temperature Sensor NTC Suction Pressure Sensor - Modbu TX Va!ve

Heating Controls

Part Number ! QTY Description

1 Bypass Valve 4..20ma

1 Pressure Sensor

1 TX Valve

Other

Part Number QTY , Description

M3235 \ 3 Energy Meters

SCADA System - Any suitable system, for example - CitectScada Functional requirements

All PLC IO tags are listed in functional groups. An example tag is shown PLC Digital Inputs

Variable Name Address Comment

Compressor_Speed1 !O O Refrigeration Compressor Speed 1

Compressor_Speed2 10.1 Refrigeration Compressor Speed 2

Oil_Differential_Press !0 2 Oil Differential Pressure Switch

Compressor_Overload I0.3 Compressor Motor Thermistor

Motorjnterlock I0.4 Compressor Motor Interlock

High_Pressure I0 5 Compressor High Pressure

Low_Pressure I0.6 Compressor Low Pressure

PLC Digital Outputs Variable Name Address Comment

K1_Compressor QO.O Refrigeration Compressor Part Winding 1

K2_Compressor Q0.1 Refrigeration Compressor Part Winding 2

Water_Vlv_Open Q0.2 Water Out Solinod Valve

Condenser_Vlv_Open Q0.3 Condenser Solenoid

Vacuum_Pump_On Q0.4 Vacuum_Pump

Vacuum_Vlv_Open Q0.5 Vacuum Shut Off Valve

Q0.6 Heat Exchange Bypass Valve (Analogue position could be

Bypass_V!v_open used instead)

Oil_pmp_On Q0.7 Oil Circulation Pump

Oil_Heat_on Q1.0 Oil Heater

Alarm Q1 .1 Alarm

Air_Vlv_Open Q1 .2 Air Out Solenoid Valve

Meter_Reset Ό 1 .3 Energy Meter Reset

PLC Analog Inputs

PLC Analog Outputs

To optimise performance a variable positioning valve is used instead of a bypass valve as this will restrict flow as the suction pressure reaches its set point allowing for a smoother graph.

CitectSCADA

The CtiectSCADA system provides supervisory control of the dryer. A dashboard is provided to display important information to operators. Further detail may be displayed through navigational control of the system.

Example CitectSCADA Controls:

Digitals

Set points

Example CitectSCADA Status:

Variable name Address Comment

Oil heater Event

Alarm Alarm Generic alarm to indicate something is wrong with the system.

Air out solenoid valve Event

Oil differential pressure Alarm Buzzer

Compressor thermal OL Alarm Buzzer

High pressure Alarm Buzzer

Low pressure Alarm Buzzer

Suction sensor fault Alarm Buzzer

Delivery temp fault Alarm Buzzer

Vacuum sensor fault Alarm Buzzer

Auto cycle complete Event Sounds buzzer as pulse

Vacuum achieved Event

Heat cycle running Event

Suction pressure high Alarm Buzzer

Vacuum lost Alarm Buzzer

Temperature Event

Finish intersection Event

Analogies

Description of process

Refer to the process flow chart in Figure 38. Start Compressor

• The compressor starts automatically when the auto start push button is pressed from the CitectSCADA and the compressor interlocks are ok.

• Compressor start interlocks

o High pressure ok

o Low pressure ok

o Oil pressure ok

o Thermal overload interlock ok

o Remedy D.O.L.

• The compressor consists of two windings and will be started on a 500ms offset.

• Whenever there is feedback received from the contactor "K1" that the compressor is

running the condenser solenoid will open.

• Note at any point if the compressor interlocks are not OK the compressor will stop and sound an alarm. The alarm will need to be acknowledged before the compressor can start again.

Start Vacuum Pump

• The vacuum pump will run whenever the compressor is running (feedback from "K1"). Vacuum Valve

• The vacuum valve will be opened once the vacuum pump has been running for more than 2 minutes. The valve will close whenever the vacuum pump turns off or the auto cycle completes.

Air valve

• The air valve is only opened when the auto sequence is complete.

Water valve

• The air in valve is only opened when the fridge is changed and turned off to defrost.

Monitor vacuum • For the heat sequence to start, Vacuum must be achieved by the absolute pressure reading below the vacuum start set point.

• Once the heat sequence has started, the vacuum run time set point will be used to switch off the heat.

Heat cycle

• The heat cycle controls 3 outputs

o Bypass valve (or variable positioning valve)

o Heating element

o Oil pump

• The oil pump is turned on when heat cycle begins and is then only turned off once the freeze drier is stopped or is in fault.

• The heating element is turned on when the following conditions are met:

o The oil delivery temperature must reach boost set point (eg. 20°C) before the

element can be used.

o The auto sequence must not be complete.

o The oil discharge temperature must below its set point.

o The oil must be circulating through the freeze dryer.

• If these conditions are not met, the heating element is turned off.

• The bypass solenoid controls when heat is applied to the freeze drier. For heat to be applied the following conditions must be met.

o The vacuum must be below its set point (running).

o The suction pressure must not be above its set point.

Auto sequence finish

• An auto sequence finish flag is set when the following conditions have been met:

o Suction pressure dropped

o Maximum temperature reached

o Safety margin time expired.

• Once this has been achieved the freeze drier will shut down and perform the following. o Close vacuum valve

o Open air in valve

o Close water out valve.

• Once the drying cycle is complete, after 15 minutes the vacuum pump will be shut down.

• Holding pattern until someone presses 'stop'

Alarms

There are a number of alarms in the system that will report in CitectSCADA and can be configured to cause an audible alarm.

• Compressor alarm - audible buzzer - if any of the following conditions exist, the

compressor alarm will be raised.

o Thermal overload

o High pressure

o Low pressure

o Oil pressure

• Sensor fault - audible buzzer - a sensor fault is triggered if any of the following sensors go out of range:

o Suction pressure

o Delivery temperature

o Discharge temperature

o Vacuum pressure

o (The vacuum and compressor remain on during this alarm state.)

• Failure to achieve vacuum

o An alarm may be set to alert if the dryer fails to reach vacuum run set point within a defined period (eg. 6 hours).

o The vacuum and compressor remain on during this alarm state.

• Oil circulation pump

o An alarm may be set if the oil pressure fails to meet or exceeds set points. o The vacuum and compressor remain on during this alarm state.

• Vacuum lost

o After vacuum is achieved, if the pressure is above a set point for a set period of time (for example 10 seconds if above set point by 20 mb), then an alarm will be generated and may for example shut one or more valves.

• Suction pressure high

o Once the drying process has started, if the pressure rises above a set point for a period of time an alarm will be raised. (For example 6 hours and 100 kpa.)

Other possible functionality of this example implementation in a multi-dryer installation:

· Vacuum locks - when starting a new batch the system will ensure that when the vacuum valve is opened, it will not remove the vacuum from the other driers. This means that it may be better to close the valve once vacuum has been achieved and not to leave open through the drying process. If this is not possible then the other valves must close during the initial vacuum is made in a newly stocked drier.

· Manual control will be introduced on a device level. This means that it will be possible to turn the heating element on and off without affecting other devices in the system.

• Maintenance control will be done manually - it will remove the system from automatic control and return everything back to its normal position and allow manipulation of devices without interlocks.

· Remote access - the interface will be accessible remotely, for example via an internet interface. Figures 39-42 depict example user interface screens for such access.

Example 9

Specifications of an example freeze-drying unit according to the invention.

Description - a compact modular design fully transportable low temperature freeze-drying unit. Chamber

• Overall length - 5500mm

• Overall width - 1850mm

• Overall height - 2750mm

Vapour condensing unit • Construction - stainless steel and copper

• Capacity - 1000kg ice

• Surface temperature - -60°C

• Refrigeration - Bitzer 9.2 Kw Double Stage

Shelving System

• Construction - modular aluminium construction 64 shelf capacity internal circuited oil heating.

• Shelf heating - achieved from food grade silicone oil heated from refrigeration system and 4 Kw electrical boost.

· Shelf temperature - -25°C to +50°C

• Trays - 64 stainless steel 2380mm length x 545mm width x 20mm height

• Tray surface area - 1 .30 mt²

• Total tray area - 83.2 mt²

Vacuum system

· Javac rotary vane 300Lt/Min high efficiency pump capable of maintaining a vacuum

pressure of 2mb.

Control system - eg. CitectSCADA Programmable logic controller supported by Schneider electrics.

Power requirements - 3 phase 415 volt 50Hz 25 Amps

Electrical - Fully automated or full manual control operation. Programmable Logic Controller (PLC) driven drying operation is programmable to specific products or custom requirements. Efficient in design and operation this drier operates on 25 Amps per phase. The program also incorporates a self diagnostic system fault mode. Electrical controls are located near the rear of the unit for ease of access.

Chamber - 304 stainless steel construction featuring 200mm inspection ports from both front and rear. All refrigeration and electrical components are rubber mounted above the chamber. Incorporated within the design is the silicon oil reciprocal system, used for heating the racking module. Refrigeration - low temperature refrigeration is generated from a Bitzer 9.2 Kw double stage compressor using 404 refrigerants. The internal ice vapour condensing unit consists of 8 equal length circuits distributed by a programmable electronic expansion valve. This coil operates at a surface temperature of -50°C capable of condensing 10Lt of moisture per hour.

Racking - The racking module comprises a circuited tubular aluminium construction which allows for the circulation of the heat medium silicon oil thus achieving even and efficient heat transfer. The module will accommodate 64 stainless steel trays achieving a total working surface area of 83.2 mt² equating to approximately 1000kg of product capacity.

Heat source - reclaimed heat from the refrigeration system is used to heat the food grade silicon oil assisted by a 4Kw electrical boost element.

Claims

We claim

1. An apparatus for freeze drying a product comprising a heat exchanger to recycle and

enable reuse of heat generated during operation.

2. An apparatus for freeze drying a product comprising at least one sensor to sense a freeze drying parameter and a heat exchanger to recycle and enable reuse of heat generated during operation.

3. An apparatus for freeze drying a product comprising a computing device to receive

information about a freeze drying process and compute and report one or more pieces of information about the process.

4. A rack for a freeze drying apparatus comprising a conduit for flow of a heat transfer

medium.

5. A method of freeze drying a product comprising recycling heat generated during operation.

6. A method of freeze drying a product comprising monitoring an operational parameter and automatically adjusting operation to maintain operation within a pre-set guideline for that parameter.

7. A method of freeze drying a product comprising maintaining a heat transfer medium with in a defined temperature range so as to reduce energy requirements.

8. A computerised method of freeze drying a product comprising: receiving information in relation to one or more critical control points and creating a batch recipe from the at least one critical control point.

9. A non-transitory computer-readable medium storing instructions for execution by a

processor to control a freeze dryer, the instructions including: code to enable receipt of information relating to one or more critical control points; code to enable storage of the critical control point information; code to computationally create a batch recipe from the at least one critical control point.

10. A computerised method of freeze drying a product comprising: receiving information in relation to one or more critical control points; creating a batch recipe from the at least one critical control point; computing a batch finish point and reporting the batch finish point.

1 1 . A non-transitory computer-readable medium storing instructions for execution by a

processor to control a freeze dryer, the instructions including: code to enable receipt of information relating to one or more critical control points; code to enable storage of the critical control point information; code to computationally create a batch recipe from the at least one critical control point; and code to compute a batch finish point.