# US 5,701,745 A · Cryogenic cold shelf > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,701,745 A - Document ID: US5701745A - Status: Granted - Kind: A - Application number: 08/768,061 - Filed: 1996-12-16 - Granted: 1997-12-30 - Earliest claimed: 1996-12-16 - Assignees: Praxair Technology, Inc. - Inventors: Alan Tat Yan Cheng; Donald Leonard DeVack - Web page: https://patentgrep.com/patent/US5701745A ## CPC - F26B 5/06: the process involving freezing - Y10S 165/908: Fluid jets - F26B: DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM (drying devices for combines A01D41/133; racks for drying fruit or vegetables A01F25/12; drying foodstuffs A23; drying hair A45D20/00; body-drying implements A47K10/00; drying household articles A47L; drying gases or vapours B01D; chemical or physical processes for dewatering or like separating liquids from solids B01D43/00; centrifugal apparatus B04; drying ceramics C04B33/30; drying yarns or fabrics in association with some other form of treatment D06C; drying frames for laundry without heating or positive air circulation, domestic laundry-or spin-driers, wringing or hot pressing laundry D06F; furnaces, kilns, ovens F27) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A cryogenic cold shelf for use in a freeze drying system having a cryogen distributor for passing cryogenic fluid into the shelf volume of the cold shelf at differing rates so as to even refrigeration provided over the entire shelf resulting in a uniform temperature over the cold shelf. ## Claims ### Claim 1 A cryogenic cold shelf comprising spaced panels defining a shelf volume, and a cryogen distributor within said shelf volume in flow communication with a source of cryogenic fluid and capable of having cryogenic fluid flow therethrough, said cryogen distributor comprising a main flow path having a first leg and a second leg downstream of the first leg, said first leg having a plurality of first branches extending from the first leg, and said second leg having a plurality of second branches extending from said second leg and oriented between said first branches. ### Claim 2 (depends on 1) The cryogenic cold shelf of claim 1 wherein the first leg is positioned in a central area of the shelf volume and the second leg is positioned in a peripheral area of the shelf volume. ### Claim 3 (depends on 1) The cryogenic cold shelf of claim 1 further comprising means for withdrawing cryogenic fluid from the shelf volume, said withdrawal means comprising a withdrawal line having a length and an exhaust and having a plurality of withdrawal branches along its length, at least one withdrawal branch further from the exhaust having perforations which are larger than perforations on at least one withdrawal branch which is closer to the exhaust. ### Claim 4 (depends on 1) The cryogenic cold shelf of claim 1 further comprising a joint for connecting the cryogen distributor to the source of cryogenic fluid, said joint comprising a packing gland and a gas heating gland around the packing gland, said gas heating gland having a means for receiving warm gas and a means for exhausting warm gas, said packing gland surrounding piping of the cryogen distributor which is capable of movement relative to said packing gland. ### Claim 5 (depends on 1) The cryogenic cold shelf of claim 1 wherein the source of cryogenic fluid is a source of nitrogen. ### Claim 6 A cryogenic cold shelf comprising spaced panels defining a shelf volume, and a cryogen distributor within said shelf volume in flow communication with a source of cryogenic fluid and capable of having cryogenic fluid flow therethrough, said cryogen distributor comprising a main flow path having a cryogenic fluid input and having a length extending through the shelf volume, and having a plurality of branches communicating with the main flow path along its length, said branches having perforations for passing cryogenic fluid out from the cryogen distributor into the shelf volume, at least one branch positioned closer to the cryogenic fluid input having smaller perforations than at least one branch positioned further from the cryogenic fluid input. ### Claim 7 (depends on 6) The cryogenic cold shelf of claim 6 wherein the main flow path is positioned in a central area of the shelf volume. ### Claim 8 (depends on 6) The cryogenic cold shelf of claim 6 further comprising means for withdrawing cryogenic fluid from the shelf volume, said withdrawal means comprising a withdrawal line having a length and an exhaust and having a plurality of withdrawal branches along its length, at least on withdrawal branch further from the exhaust having perforations which are larger than perforations on at least one withdrawal branch which is closer to the exhaust. ### Claim 9 (depends on 6) The cryogenic cold shelf of claim 6 further comprising a joint for connecting the cryogen distributor to the source of cryogenic fluid, said joint comprising a packing gland and a gas heating gland around the packing gland, said gas heating gland having a means for receiving warm gas and a means for exhausting warm gas, said packing gland surrounding piping of the cryogen distributor which is capable of movement relative to said packing gland. ### Claim 10 (depends on 6) The cryogenic cold shelf of claim 6 wherein the source of cryogenic fluid is a source of nitrogen.