APPARATUS FOR AND METHOD OF STEAM TREATING OF PLANT FIBRES

Abstract

An apparatus for steam treating plant fibres is provided, the apparatus comprising: a steam manifold that is adapted to receive steam from a steam source and to distribute steam to a plurality of lances, the lances being configured to deliver steam into the interior volume of a batch of plant fibres; a temperature sensor for sensing a temperature of the batch of plant fibres, and a controller. The controller is configured to receive a signal from the temperature sensor, and to control the supply of steam to the lances to raise the temperature of the plant fibres to a target temperature. A method of steaming plant fibres is also provided.

Claims

1. An apparatus for steam treating plant fibres, the apparatus comprising: a steam manifold that is adapted to receive steam from a steam source and to distribute steam to a plurality of lances, the lances being configured to deliver steam into the interior volume of a batch of plant fibres; a temperature sensor for sensing a temperature of the batch of plant fibres; and a controller configured to receive a signal from the temperature sensor, and to control the supply of steam to the lances to raise the temperature of the plant fibres to a target temperature.

2. An apparatus according to claim 1, in which the apparatus comprises valve means controllable to prevent or allow the passage of steam from the steam source to the lances, and in which the valve means are controllable by the controller.

3. An apparatus according to claim 1 or 2, in which the controller comprises a temperature control feedback loop, and is configured to control the steam supply so that the temperature of the batch of plant fibres is maintained at a target temperature for a predetermined period of time.

4. An apparatus according to claim 1, 2 or 3, in which the controller is configured to stop the supply of steam when the sensed temperature exceeds a predetermined level.

5. An apparatus according to any preceding claim, in which the apparatus comprises a container configured to contain the plurality of lances and, in use, the batch of plant fibres.

6. An apparatus according to claim 5, in which the container is sealable in a gas-tight configuration, so that steam pressure inside the container can be increased above atmospheric pressure.

7. An apparatus according to claim 5 or 6, in which the container comprises an openable vent, the openable vent being controllable by the controller between an open state in which steam is vented from the interior of the container to the atmosphere, and a closed state in which steam cannot pass through the vent.

8. An apparatus according to claim 5, 6 or 7, in which the apparatus comprises a pressure sensor configured to sense a pressure inside the container, and in which the controller is configured to receive signals from the pressure sensor.

9. An apparatus according to claim 8, in which the controller comprises a pressure control feedback loop, and is configured to control the steam supply so that the pressure of steam in the container is increased to a target level.

10. An apparatus according to claim 8 or 9, in which the controller is programmed to stop the supply of steam, or to open the vent, when the pressure in the container exceeds a predetermined level.

11. An apparatus according to any preceding claim, in which the apparatus comprises a humidity sensor configured to sense a humidity inside the container, and in which the controller is configured to receive signals from the humidity sensor.

12. An apparatus according to claim 11, in which the controller comprises a humidity control feedback loop, and is configured to control the steam supply so that the humidity in the container is increased to a target level.

13. An apparatus according to claim 11 or 12, in which the controller is programmed to stop the supply of steam when the sensed humidity exceeds a predetermined level.

14. An apparatus according to any preceding claim, in which the apparatus comprises a steam generator configured to deliver steam to the manifold.

15. An apparatus according to claim 14, in which the steam generator and the manifold are provided in a shared housing.

16. An apparatus according to claim 14 or 15, in which the steam generator is configured to deliver steam to the lances at a pressure greater than atmospheric pressure, for example at least 1.2 bar, or at least 1.4 bar, or at least 1.6 bar, or at least 2 bar.

17. An apparatus according to any preceding claim, in which the controller is programmed to operate in a defrost mode for defrosting and re-hydrating frozen plant fibres, in which controller delivers steam to raise the temperature of a frozen batch of plant fibres to a target temperature range of between 3° C. and 8° C., preferably between 4° C. and 6° C., or 4° C. and 5° C.

18. An apparatus according to claim 17, in which the controller delivers steam to the batch of plant fibres until the moisture content of the batch of plant fibres is between 8% and 14%, preferably between 10% and 12% moisture content.

19. An apparatus according to any preceding claim, in which the controller is programmed to operate in a steam cleaning mode for killing bacteria on plant fibres, in which controller delivers steam to raise the temperature of a batch of plant fibres to a target temperature range of between 90° C. and 104° C.

20. An apparatus according to claim 19, in which the controller is configured to deliver steam to raise the temperature of the batch of plant fibres to a temperature of at least 90° C. for a period of at least 10 minutes, or at least 15 minutes, or at least 20 minutes.

21. An apparatus according to claim 19 or 20, in which the controller is configured to deliver steam to raise the temperature of the batch of plant fibres to a maximum temperature of 104° C. for a maximum of 30 minutes.

22. An apparatus according to any preceding claim, in which at least two of the lances have different lengths.

23. A method of steaming plant fibres, comprising the steps of: inserting a plurality of lances into a batch of plant fibres; delivering steam from a steam source, through a manifold, and out of the lances into the batch of plant fibres; sensing a temperature of the batch of plant fibres; and controlling the supply of steam to the lances in response to the sensed temperature, to raise the temperature of the plant fibres to a target temperature.

24. A method according to claim 23, in which the steam is delivered to the plant fibres at a pressure greater than atmospheric pressure, for example at least 1.2 bar, or at least 1.4 bar, or at least 1.6 bar, or at least 2 bar.

25. A method according to claim 23 or 24, in which the plant fibres are provided as a bale of plant fibres, or as a batch in a net or mesh bag, or container.

26. A method according to claim 23, 24 or 25, in which the steam supply is controlled so that the temperature of the batch of plant fibres is maintained at a target temperature for a predetermined period of time.

27. A method according to any of claims 23 to 26, in which the supply of steam is stopped when the sensed temperature exceeds a predetermined level.

28. A method according to any of claims 23 to 27, in which the plurality of lances and the batch of plant fibres are placed in a container.

29. A method according to claim 28, in which the container is sealed in a gas-tight configuration while the steam is delivered to the plant fibres, so that steam pressure inside the container increases above atmospheric pressure.

30. A method according to claim 28 or 29, in which the method comprises the step of sensing a pressure inside the container, and/or sensing a humidity inside the container.

31. A method according to claim 28, 29 or 30, comprising the step of controlling the supply of steam to reach a predetermined steam pressure inside the container.

32. A method according to any of claims 28 to 31, comprising the step of opening a valve in the container to vent steam from the interior of the container to the outside atmosphere when the pressure, or the temperature, or the humidity in the container exceeds a predetermined level.

33. A method of defrosting and re-hydrating frozen plant fibres, comprising the method of any of claims 23 to 32, in which the supply of steam is controlled to raise the temperature of a frozen batch of plant fibres to a target temperature range of between 3° C. and 8° C., preferably between 4° C. and 6° C., or 4° C. and 5° C.

34. A method according to claim 33, in which In which steam is supplied to the batch of plant fibres until the moisture content of the batch of plant fibres is between 8% and 14%, preferably between 10% and 12% moisture content.

35. A method of steam cleaning plant fibres, comprising the method of any of claims 23 to 32, in which the supply of steam is controlled to raise the temperature of a batch of plant fibres to a target temperature range of between 90° C. and 104° C.

36. A method according to claim 35, in which the supply of steam is controlled to raise the temperature of the batch of plant fibres to a temperature of at least 90° C. for a period of at least 10 minutes, or at least 15 minutes, or at least 20 minutes.

37. A method according to claim 35 or 36, in which the supply of steam is controlled to raise the temperature of the batch of plant fibres to a maximum temperature of 104° C. for a maximum of 30 minutes.

38. An apparatus or method according to any preceding claim, in which the plant fibres are animal fodder, such as hay or haylage, or in which the plant fibres are industrial hemp fibres.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0117] FIG. 1 is an overall diagrammatical view of one embodiment of the invention and illustrates the principle of operation;

[0118] FIG. 2A is an overall view of an example of a manifold and lances;

[0119] FIG. 2B is an overall view of an alternative embodiment of manifold and lances having different lengths;

[0120] FIG. 3 is a partially transparent illustration of a first embodiment of the invention in use;

[0121] FIG. 4 is a partially transparent illustration of a second embodiment of the invention in use; and

[0122] FIG. 5 is a schematic diagram of a further embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0123] Referring to FIG. 1 there is shown in general an apparatus for steam treatment of plant fibres comprising a water reservoir 20 in which is located a heating element 22. The water reservoir, or steam generator, can also be a sealed vessel and thus capable of heating water to more than its normal boiling point. A high pressure flexible hose 24, which is ideally insulated, conducts steam from the reservoir to a manifold, ideally via a flexible or universal joints 25 and 26. The manifold 1 distributes the steam into a batch of plant fibres 10.

[0124] A temperature sensor probe 27 is provided to measure a temperature inside the batch of plant fibres during steaming, and to communicate temperature signals to a controller 29.

[0125] The reservoir or steam generator optionally includes conventional safety equipment such as thermostatic settings, boil dry warning and residual current detectors (RCD) for use in damp and outdoor environments.

[0126] FIG. 2 shows a manifold, which is in the form of a generally square frame and has passages formed therein for distribution of steam. The manifold 1 is fitted with a number of substantially vertical lances 2, which are in communication with the passages. Each lance 2 has a pointed end 3 for ease of penetration into a batch of plant fibre 10. Lances 2 have apertures 4, extending a proportion of their length, for the release and distribution of steam and condensed steam into the centre of the plant fibres.

[0127] The supply of steam may be switched on or off by the controller 29. The controller is preferably programmable by a user, and is configured to control steam supply to the plant fibres, and therefore to control the steaming temperature and duration of the steaming.

[0128] The controller may be built into the apparatus or communicate with the apparatus, for example, via a wired or wireless interface. In certain embodiments, the controller may be a mobile phone, a tablet computer, or any other handheld control device. For example, an application may be downloaded onto a mobile device allowing the device to be used as a controller. The controller can be configured to provide a user interface that allows users to input desired configurations (e.g., a target temperature, target humidity, target steaming time, and/or a target steaming pressure).

[0129] The controller may comprise a data processing system, which may include one or more processors (e.g., a general purpose microprocessor and/or one or more other data processing circuits, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGA's), and the like); a network interface for connecting the controller to a network; and a local storage unit, which may include one or more non-volatile storage devices and/or one or more volatile storage devices (e.g., random access memory (RAM)). In embodiments where the controller includes a general purpose microprocessor, a computer program product may be provided. The computer program product may include a computer readable medium (CRM) storing a computer program comprising computer readable instructions. The CRM may be a non-transitory computer readable medium, such as, but not limited to magnetic media (e.g., a hard disk), optical media (e.g., a DVD), memory devices (e.g., random access memory), and the like. In some embodiments, the computer readable instructions are configured such that when executed, they cause the controller to perform tasks described herein. In other embodiments, the controller may be configured to perform tasks described herein without the need for code. For example, the data processing system may consist merely of one or more ASICs.

[0130] The apertures 4 may be vertically disposed or they may be in the form of slits or slots, extending lengthwise or helically about circular lances 2. Alternatively, the apertures may take the form of holes formed in the lances so that the steam and condensed steam permeate outwards to the extremities of the batch of plant fibres ensuring full effectiveness and contact of the steam throughout the fibres. It has been found that with use of the manifold the temperature of a bale may exceed 100 degrees Centigrade.

[0131] As a result of the lances 2a, 2b, 2c and 2d, steam is introduced into the centre of the bale or receptacle of the fibres by placing the batch of plant fibres 10 onto the manifold 1. Alternatively, the manifold 1 can be forced into a bale of plant fibres 10 from the side or above. In whichever orientation the lances penetrate so as ensure steam reaches all of the bale. If the manifold is arranged to rest on the ground during operation, an optional foot or feet 7 may be provided or formed on the manifold to prevent damage to it, for example by shock loading that may occur when a bale is dropped onto the lances.

[0132] In an alternative embodiment one or more steam distribution manifolds 1 of various lengths (to accommodate different size bales and receptacles to ensure effective central penetration) is provided. Lances 2 may be of different lengths and optionally these may be removable and fitted onto a common manifold. Thus for example in the event of damage to a lance, it may be removed and replaced with a similar lance. Alternatively, where the manifold is required for use with larger bales, longer lances may be fitted to the manifold.

[0133] FIG. 2B shows an embodiment in which five lances 2a, 2b, 2c, 2d and 2e are connected to a manifold 1. In order to provide good distribution of steam at different heights in a bale of plant fibres, the lances have different lengths, so that they extend to different heights above the manifold 1. As shown in FIG. 2B, two lances 2b and 2d on opposite sides of the manifold have a first length or height, two lances 2a and 2c on opposite sides of the manifold have a second length or height, which is greater than the first length, and a lance 2e in the centre of the manifold has a third length or height which is greater than the lengths of the other lances. Apart from the lance lengths, the design of each lance is substantially the same as described above in relation to FIG. 2A. When a large bale of plant fibres is placed on the manifold 1 for steaming, the lances will penetrate the bale so that the tips of the lances, and therefore the steam apertures, extend to different heights inside the bale. This means that steam is delivered to different points inside the bale, providing more uniform steaming throughout the large bale than would be possible with lances of uniform length.

[0134] Steam and condensed steam permeate through the plant fibres increasing the temperature of the fibres to between 90 and 105 degrees Centigrade (depending upon ambient temperature) killing thermophilic and mesophilic mould spores and other living organisms as mentioned above and effectively steam treating the fibres as well as dampening dust spores thus restricting their ability to become airborne.

[0135] The steam is distributed from the reservoir, via the hose and through the lances and where the steam condenses the water content is absorbed, in the majority, by the plant fibres leaving it damp. As the moisture content within the plant fibres increases, the temperature rises exponentially due to the increased efficiency of water as a heat conducting medium within the fibres, compared to air in the fibres' dry state.

[0136] In prior art devices, the lack of control system meant that fibres were typically steamed continuously for a long period, during which the fibres absorbed moisture and the temperature of the fibres increased exponentially. The temperature probe 27 and controller of the present device, however, allow more precise control so that the plant fibres can be heated to and maintained at a desired target temperature for the desired duration.

[0137] Depending on the programming of the controller, the plant fibres may be exposed to continuous steam from the apparatus, or the steam supply may be intermittently stopped and started to maintain the fibres at a desired temperature, for example.

[0138] The controller may be programmed to operate in a steam cleaning mode for killing bacteria on plant fibres. In order to kill microorganisms the fibres, for example animal fodder, may typically be heated to a temperature of at least 90 degrees centigrade for not less than 10 minutes.

[0139] Alternatively, the controller may be programmed to operate in a defrost mode for defrosting and re-hydrating frozen plant fibres, in which the controller delivers steam to raise the temperature of a frozen batch of plant fibres to a target temperature range of between 3° C. and 8° C.

[0140] In defrost mode, the controller may delivers steam to the batch of plant fibres until the moisture content of the batch of plant fibres is between 8% and 14%, preferably between 10% and 12% moisture content.

[0141] This defrost mode may be particularly suitable, for example, for defrosting industrial hemp which has been frozen for storage and transport.

[0142] A user can select the mode of operation of the controller such that it is defrost mode or a steam cleaning mode.

[0143] The aforementioned apparatus can be used either in open space or within an enclosed environment, such as horse box, stable or barn.

[0144] In a preferred embodiment the manifold 1 and lances 2 are provided inside a designated sealable container 30, which is preferably insulated and gas-tight so that steam pressure may be built up within the container.

[0145] FIG. 3 illustrates a first embodiment of a steaming apparatus in which a batch of plant fibres contained in a net 10 are steamed in a container 30. A manifold 1 is positioned in the base of the container 30, so that in use the batch of plant fibres is lowered down onto the lances 2 so that they penetrate into the batch of fibres. A temperature probe 27 also projects upwards from the base of the container so that it penetrates into the batch of fibres.

[0146] FIG. 4 shows an alternative embodiment of the steaming apparatus including a larger container 30 which contains two manifolds 1 in its base. In this embodiment, the temperature probe 27 is provided on the lid 35 of the container.

[0147] When closed, the lid 35 preferably forms a gas-tight seal with the container walls so that the steam pressure in the container can be increased to a desired pressure. A pressure sensor (not shown) is provided in a container wall, which communicates pressure signals to the controller.

[0148] A closable vent 40 is provided in the container lid 35 for releasing steam from the interior of the container. Opening and closing of the vent is controllable by the controller, either in response to a threshold pressure being reached, or to release steam from the container at the end of the desired steaming time.

[0149] In the embodiment of the apparatus shown in FIG. 5, the manifold 1 is positioned directly above the boiler 20, with a valve 45 controlling the flow of steam from the boiler to the manifold. The opening and closing of the valve 45 is controllable by a controller 49. As the boiler and the manifold are adjacent to one another, high pressure steam may be generated in the boiler and supplied to the manifold without having the chance to cool down and condense in a connecting hose 24. This may be particularly preferred for supplying high pressure steam to the batch of plant fibre 10 in the interior of the container 30, as it may allow rapid heating of the plant fibre to kill spores and microorganisms. Once the plant fibre has been heated to sufficient temperature for long enough, the controller preferably opens the vent 40 to release the steam in the container and reduce the amount of condensation left in the plant fibres.