Apparatus and method for vacuum freeze drying substances in a tunnel dryer having sealing locks

Claim 1

A FREEZE DRYING METHOD FOR USE IN A FREEZE DRYING INSTALLATION HAVING AN EVACUABLE FEEDING LOCK, AN EVACUABLE DISCHARGE LOCK, AN EVACUABLE DRYING CHAMBER CONNECTED BETWEEN THE FEEDING AND DISCHARGE LOCKS AND SEPARATED THEREFROM BY DOOR MECHANISMS ADAPTED TO MAINTAIN A PRESSURE DIFFERENTIAL AND TO ALLOW PASSAGE OF A MATERIAL TO BE DRIED, A REFRIGERATED CONDENSER CONNECTED FOR GAS COMMUNICATION WITH THE EVACUABLE FEEDING LOCK, HEATING MEANS POSITIONED IN SAID DRYING CHAMBER AND ADAPTED TO APPLY SUBLIMATION INDUCING HEAT TO A MATERIAL BEING DRIED, AND WATER VAPOR REMOVAL APPARATUS CONNECTED TO SAID DRYING CHAMBER AND ADAPTED TO REMOVE WATER VAPOR PRODUCED BY SAID SUBLIMATION, WHICH METHOD COMPRISES THE FOLLOWING STEPS; POSITIONING THE MATERIAL TO BE DRIED INTO THE FEEDING LOCK, EVACUATING THE FEEDING LOCK, PRODUCING WITHIN THE FEEDING LOCK RAPID SURFACE EVAPORATION OF THE MATERIAL TO CAUSE FREEZING THEREOF, TRANSPORTING THE FROZEN MATERIAL INTO THE EVACUATED DRYING CHAMBER, FREEZE DRYING THE MATERIAL WITHIN THE DRYING CHAMBER, TRANSPORTING THE DRIED MATERIAL INTO THE EVACUATED DISCHARGE LOCK, AND REMOVING THE DRIED MATERIAL FROM THE DISCHARGE LOCK.