Patent EA-004030-B1 (EA)
Title: Method and apparatus for sterilising and/or pasteurising growth media
IPC: A01G1/04
Filed: 2001-02-01
Abstract: 1. A discontinuous-or batch-method of at least partially sterilising or homogeneously and completely pasteurising a substrate, in which method: -in a first step, said substrate is loaded into a hollow vessel, the hollow vessel being provided with means for at least partly sterilising or pasteurising the substrate; -in a second step the hollow vessel is rotated and heat energy is supplied to the substrate, during the rotation of the vessel the substrate being transported towards an end of the vessel in a first direction through a tubular section located within the hollow vessel, the tubular section having a first and a second end; -in a third step, the substrate is discharged from the second end of the tubular section into the rotating hollow vessel and is transported in a second direction opposite to that of the first direction in the hollow vessel until it reaches the first end of the tubular section, the substrate transported in the first direction being separated from the substrate transported in the second direction by a wall of the tubular section; and -the second and third steps are repeated to obtain homogeneous and at least partial sterilisation or homogeneous and complete pasteurisation of said substrate. 2. The method according to claim1, wherein the second step is effected by transporting the substrate in the first direction within the tubular section by means of transport device situated substantially inside said tubular section. 3. The method according to claim 2, wherein the substrate is discharged from the vessel by reversing the direction of the transport device. 4. The method according to any of claims 1 to 3, wherein during the transport in the second direction the substrate is subjected to tumbling. 5. A method according to any of claims 1 to 4, wherein the homogeneously completely pasteurised or at least partly sterilised substrate is subjected to a cooling step in the vessel. 6. The method according to any previous claim further comprising the step of introducing a fluid for moistening said substrate. 7. The method according to claim 6, wherein the quantity of moistening fluid introduced in the first step is such that the concentration of dry material in the sealed rotary machine is from 20% by weight to 60% by weight. 8. The method according to any of the previous claims wherein the hollow vessel is sealed during sterilisation or pasteurisation. 9. The method according to any previous claim, wherein the substrate is an organic material. 10. The method according to claim 9, wherein the substrate is a growth or nutrient medium. 11. The method according to claim 10, wherein the growth medium is seeded inside the vessel, after it has cooled, before the step of discharging it from the vessel. 12. Apparatus for at least partly sterilising or pasteurising a substrate, comprising: -a hollow vessel which can be rotated about a rotation axis, the vessel being provided with means for at least partly sterilising or completely pasteurising the substrate ; -an opening for loading the substrate into the vessel (for example from a hopper or a conventional transport system); -a first transport device for transporting the substrate and extending throughout a substantial portion of the interior of the hollow vessel, and -a tubular partition surrounding the first transport device to separate transport of the substrate with the transport device towards one end of the vessel in a first direction from transport of the substrate within the hollow vessel in a direction opposite to the first direction. 13. The apparatus according to claim 12, wherein the tubular partition extends over at least a majority portion of the length of the first transport device. 14. The apparatus according to claim 12 or 13, further comprising means for introducing a moistening fluid into the vessel. 15. The apparatus according to any of claims 12 to14, further comprising means for discharging the substrate from the vessel. 16. The apparatus according to claim 15, wherein the discharging means comprises a reverse drive for the first transport device. 17. The apparatus according to any of the claims 12 to 16, wherein the vessel is provided with a means for sealing during processing. 18. The apparatus according to any of claims 12 to 17, wherein the tubular partition and the hollow vessel are elongate, cylindrical or quasi-cylindrical, parallelepiped or quasiparallelepiped. 19. The apparatus according to any of the claims 12 to 18, wherein the tubular partition comprises a means for preventing clogging of the substrate within the tubular partition. 20. The apparatus according to any of the claims 12 to 19 wherein the rotation axis of the vessel is substantially horizontal or with a tilt of less than 25 degree and preferably less than10 degree . 21. The apparatus according to any of the claims 12 to 20 wherein, the means for sterilising or pasteurising the substrate comprises a fluid circulation jacket around the tubular partition and/or a fluid circulation envelope on a wall of the vessel. 22. The apparatus according to any of claims 12 to 21, wherein the first transport device is a screw, worm spiral conveyor. 23. The apparatus according to any of the claims 12 to 22 further comprising a second transporting device for transporting the substrate in the second direction. 24. The apparatus according to claim 23, wherein the second transporting device is adapted to allow tumbling of the substrate in the vessel. 25. The apparatus according to any of the claims 12 to 24, wherein the first transport device is partly surrounded by a trough which is coaxial with the tubular partition.