Vacuum processing apparatus

Abstract

The present invention relates to an apparatus ( 10 ) for vacuum processing articles ( 12 ). The apparatus comprises a processing region ( 14 ) in which articles can be vacuum processed at a processing pressure and a loading region ( 18 ) into which articles can be loaded into the apparatus at ambient pressure. A plurality of article carriers ( 20 ) are provided for carrying articles from the loading region to the processing region along an enclosed passage ( 24 ) so that articles can be vacuum processed. The carriers ( 20 ) comprise respective sealing means ( 26 ) for sealing against an inner surface of the passage when carrying articles along the passage. The sealing means ( 26 ) resist the flow of gas or vapour past the sealing means along the passage from the loading region to the processing region so that articles loaded at ambient pressure in the loading region and carried to the processing region can be vacuum processed at processing pressure.

1 - 31 . (canceled) 
     
     
         32 . Apparatus for vacuum processing articles, comprising:
 a fluid passage adapted to receive at least one carrier at a loading region at atmospheric pressure;   carriers having at least one seal   whereby in use an intermediate volume is defined within which one or more articles are received for processing;   a processing region defined in said passage, whereat the pressure is low or high with respect to atmospheric pressure;   a means to displace carriers along the passage, from the loading region to the processing region and subsequently to an exit region; and   at least one pump or pressure differential means which, in use, is in fluid communication with the passage and which is operative to reduce or increase the internal pressure of carriers within the passage intermediate said loading region and said exit region, wherein the at least one seal comprises a flexible material sandwiched between two discs so as to reveal an annulus of flexible material which conforms to the cross section of the fluid passage.   
     
     
         33 . Apparatus as claimed in  claim 32 , wherein the seal is disc shaped in order to conform with a pipe with a circular cross section. 
     
     
         34 . Apparatus as claimed in  claim 32 , wherein seals are formed from pneumatic “U”, “T” or “V” type seals extending around a first end and a second end of the carrier, whereby in use, a pressure differential is created across the flange. 
     
     
         35 . Apparatus as claimed in  claim 32 , wherein the seal comprises a flexible material compounded with or laminated with a fluoro-polymer such as poly-tetrafluroethane (PTFE) or molybdenum disulphide, so as to reduce friction between the seals and the wall, whilst in use still maintaining an airtight (or near airtight) seal. 
     
     
         36 . Apparatus as claimed in  claim 35 , wherein the seal is protected from a process environment by a flexible inert covering, so as to reduce contamination of the process by the seal material, whilst in use still allowing the seal to maintain a gas tight (or near gas-tight) seal. 
     
     
         37 . Apparatus as claimed in  claim 32 , wherein the walls are coated with a material, such as poly-tetrafluroethene (PTFE), so as to reduce friction between the seals and the wall, whilst in use still maintaining an airtight (or near airtight) seal. 
     
     
         38 . Apparatus as claimed in  claim 32 , wherein valves are located at intervals, in the wall of the fluid passage and which are connected to the or each pump, thereby acting to reduce the pressure within the volume defined between the seals of a carrier and the wall of the fluid passage. 
     
     
         39 . Apparatus as claimed in  claim 32 , wherein a control means is provided that operates so as to actuate pumps and/or valves in synchronism with the means to displace the carriers, whereby on displacement of one or more carriers from a first location to a second location, pumps and/or valves are energised so as to at least maintain the pressure differential between a location within a carrier, (as defined by the walls of the fluid passage and the volume intermediate the seals of the carrier), with respect to a location outside the carrier. 
     
     
         40 . Apparatus as claimed in  claim 32 , wherein the processing region is selected from the group consisting of a plasma processing region, a vacuum deposition region, a desiccation region, an infusion region and a freeze drying region. 
     
     
         41 . Apparatus as claimed in  claim 32 , wherein carriers are cylindrical shaped and hollow with an open aperture for loading. 
     
     
         42 . Apparatus as claimed in  claim 32 , wherein the means to displace carriers includes actuators from the group comprising: an hydraulic ram; a pneumatic ram; an electro-magnetic actuator; a ball or roller screw actuator; one or more motorized conveyors; and a direct mechanical engagement means. 
     
     
         43 . Apparatus as claimed in  claim 32 , comprising:
 an unloading region from which articles can be unloaded from the apparatus at ambient pressure; and   a second enclosed pre-conditioning passage along which said carriers can carry new un-processed articles to the loading region.   
     
     
         44 . Apparatus as claimed in  claim 43 , wherein said sealing means of said carriers seals against an inner surface of said second enclosed pre-conditioning passage so that when carrying articles along the second passage, said sealing means resist the flow of gas or vapour past said sealing means along said second passage from the unloading region to the processing region so that articles are pre-conditioned at processing pressure and carried to the loading region for loading at ambient pressure. 
     
     
         45 . Apparatus as claimed in  claim 43 , wherein said second pre-conditioning passage comprises an intermediate pressure region adapted to be maintained at a pressure between ambient pressure and processing pressure so that a pressure differential across the sealing means of carriers in said second passage is less than the pressure differential between ambient and processing pressure. 
     
     
         46 . Apparatus as claimed in  claim 45 , wherein said intermediate pressure region comprises a plurality of sub-regions adapted to be maintained at respective pressures from one sub-region to the next along said passage towards said processing region. 
     
     
         47 . Apparatus as claimed in  claim 32 , wherein enclosed passages form a circuit along which said carriers circulate between ambient pressure regions in which articles can be loaded and unloaded and processing region at processing pressure in which articles can be processed. 
     
     
         48 . A method of processing articles, comprising the steps of:
 loading a carrier with one or more articles to be processed and placing the carrier in a passage at a loading region at atmospheric pressure, said carrier having first and second seals defining an intermediate volume within which one or more articles are received for processing;   urging carriers along the passage from a region of a first pressure to a region of lower pressure until the carrier arrives at a processing region that is substantially a vacuum;   processing said articles that are located in the carrier at the processing region;   displacing carriers from the processing region to an exit region.