# US 5,347,725 A · Method and apparatus for vacuum drying colloidal substances > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,725 A - Document ID: US5347725A - Status: Granted - Kind: A - Application number: 08/067,439 - Filed: 1993-05-24 - Granted: 1994-09-20 - Earliest claimed: 1992-06-09 - Assignees: Sato Iron Works Co., Ltd. - Inventors: Takuya Sato - Web page: https://patentgrep.com/patent/US5347725A ## CPC - F26B 25/006: {Separating volatiles, e.g. recovering solvents from dryer exhaust gases} - F26B 5/041: {for drying flowable materials, e.g. suspensions, bulk goods, in a continuous operation, e.g. with locks or other air tight arrangements for charging/discharging} - 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) ## Abstract A colloidal substance is injected into a vacuum chamber to be dehydrated therein. The dehydrated substance is extracted from the vacuum chamber by a screw extruder disposed at a bottom of the vacuum chamber. A gas resulting from the dehydration is drawn from the vacuum chamber into a surface condenser to be cooled through an indirect heat exchange with cooling water. After the dehydration of the substance, the extraction of the dehydrated substance and the cooling of the gas are carried out in parallel. ## Claims ### Claim 1 A method of vacuum drying a colloidal substance comprising the steps of: dehydrating said colloidal substance by subjecting the substance stored in a raw material tank of a raw material supplying device to a heat exchange with heating vapor in a heat exchanger disposed upstream a vacuum drying tower, and then injecting the substance into a vacuum chamber; kneading and extracting a substance dehydrated in said vacuum chamber; cooling a gas withdrawn from said vacuum chamber through an indirect heat exchange with a refrigerant by utilizing a surface condenser; discharging a gas sucked and exhausted from said vacuum chamber into the atmosphere; and carrying out said extracting step and said cooling step in parallel after said dehydrating step. ### Claim 2 (depends on 1) A vacuum drying method as defined in claim 1, wherein the dehydrating step is carried out such that said vacuum chamber has an internal gas pressure maintained at a lower level under control of a suction device. ### Claim 3 (depends on 1) A vacuum drying method as defined in claim 1, wherein the kneading and extracting step is carried out by operating a substance extracting device disposed at a bottom of said vacuum chamber to form and output the dehydrated substance with kneading and extruding action of a helical screw of said extracting device. ### Claim 4 (depends on 1) A vacuum drying method as defined in claim 1, wherein the cooling step is carried out by subjecting the gas withdrawn from said vacuum chamber to an indirect heat exchange in a cooling device with cooling water supplied as the refrigerant from a chiller. ### Claim 5 An apparatus for vacuum drying a colloidal substance comprising: raw material supplying means for supplying said colloidal substance; a vacuum drying tower for vacuum dehydrating said colloidal substance; suction means for exhausting a gas from said vacuum drying tower to maintain a vacuum in said vacuum drying tower; substance extracting means for receiving a treated substance from said vacuum drying tower, and kneading and outputting the substance; and cooling means mounted in an intermediate position of an exhaust line extending from said vacuum drying tower to said suction means to cool the gas exhausted from said vacuum drying tower; wherein said cooling means is a surface condenser for effecting an indirect heating exchanger; and wherein said raw material supplying means comprises a heat exchanger for heating said substance through an indirect heat exchange with heating vapor. ### Claim 6 (depends on 5) A vacuum drying apparatus as defined in claim 5, wherein said raw material supplying means includes: a raw material tank for storing the colloidal substance to be treated; and a transporting pump for delivering said substance in said raw material tank to said heat exchanger and said vacuum drying tower. ### Claim 7 (depends on 5) A vacuum drying apparatus as defined in claim 5, wherein said vacuum drying tower includes: a vacuum chamber connected in an upper position thereof to said exhaust line and having an opening in a bottom thereof for communicating to said substance extracting means; and a substance injecting nozzle disposed in a vertically intermediate position of said vacuum chamber. ### Claim 8 (depends on 7) A vacuum drying apparatus as defined in claim 7, wherein said substance extracting means includes: a helical screw communicating with said opening in the bottom of said vacuum chamber; and a forming die disposed at an outlet end of said helical screw. ### Claim 9 (depends on 5) A vacuum drying apparatus as defined in claim 5, wherein said cooling means includes an outer case defining therein two spiral passages adjacent each other, one of said passages being connected to an exhaust inlet of said exhaust line and to an exhaust outlet of a further exhaust line, the other passage being connected to a water inlet of a cooling water line for transmitting cooling water from an external chiller, and to a water outlet of a cooling water line for transmitting the water to the chiller. ### Claim 10 (depends on 9) A vacuum drying apparatus as defined in claim 9, wherein said cooling means further includes a drain tank disposed in a lower position thereof and out of communication with said exhaust lines and said cooling water lines, for collecting dew condensation adhering to a partition wall used in said indirect heat exchange. ### Claim 11 (depends on 5) A vacuum drying apparatus as defined in claim 5, wherein said colloidal substance is neat soap. ### Claim 12 (depends on 5) A vacuum drying apparatus as defined in claim 5, wherein said suction means includes a vacuum pump connected to an exhaust line extending from said cooling means, and after-treatment means connected to an exhaust line extending from said vacuum pump.