# US 5,706,842 A · Balanced rotating spray tank and pipe cleaning and cleanliness verification system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,842 A - Document ID: US5706842A - Status: Granted - Kind: A - Application number: 08/412,674 - Filed: 1995-03-29 - Granted: 1998-01-13 - Earliest claimed: 1995-03-29 - Assignees: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Inventors: Raoul E. B. Caimi; Eric A. Thaxton - Web page: https://patentgrep.com/patent/US5706842A ## CPC - B08B 9/28: the apparatus cleaning by splash, spray, or jet application, with or without soaking - B05B 3/02: with rotating elements (electric spraying discharge apparatus characterised by having rotary outlet or deflecting elements B05B5/04) - B05B 13/0636: {by means of rotatable spray heads or nozzles} - B08B 3/02: Cleaning by the force of jets or sprays - B08B 9/0433: {provided exclusively with fluid jets as cleaning tools} - B08B 9/0936: {using rotating jets} - Y10S 261/78: Sonic flow - B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL - B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A system for cleaning and verifying the cleanliness of the interior surfaces of hollow items, such as small bottles, tanks, pipes and tubes, employs a rotating spray head for supplying a gas-liquid cleaning mixture to the item's surface at a supersonic velocity. The spray head incorporates a plurality of nozzles having diverging cross sections so that the incoming gas-liquid mixture is first converged within the spray head and then diverged through the nozzles, thereby accelerating the mixture to a supersonic velocity. In the preferred embodiment, three nozzles are employed; one forwardly facing nozzle at the end of the spray head and two oppositely facing angled nozzles exiting on opposite sides of the spray head which balance each other, and therefore impart no net side load on the spray head. A drive mechanism is provided to rotate the spray head and at the same time move the head back and forth within the item to be cleaned. The drive mechanism acts on a long metal tube to which the spray head is fixed, and thus no moving parts are exposed to the interior surfaces of the items to be cleaned, thereby reducing the risk of contamination. ## Claims ### Claim 1 A system for cleaning interior surfaces of hollow items including bottles, tanks, pipes and tubes comprising: a spray head containing a plurality of diverging cross section spray nozzles, each said spray nozzle having an inlet and an outlet with the inlet having an area smaller than the outlet area; means for supplying a gas-liquid mixture to said spray head; and means for rotating said spray head, whereby the spray nozzles accelerate the gas-liquid mixture to a supersonic velocity at the outlet of the nozzles and impinge the mixture on the interior surfaces of a hollow item. ### Claim 2 (depends on 1) The system of claim 1 wherein said plurality of diverging cross section spray nozzles includes first and second balanced, oppositely facing nozzles having longitudinal axes parallel to one another, but disposed at an angle relative to a longitudinal axis of said spray head, said first and second nozzles having outlet ends disposed on first and second opposite side walls of said spray head. ### Claim 3 (depends on 2) The system of claim 2, wherein said first nozzle is generally forwardly facing relative to a front end of said spray head, and said second nozzle is generally rearwardly facing relative to the front end of said nozzle, whereby said second nozzle is particularly suited for spraying inlet areas of a hollow item when said spray head is positioned therein. ### Claim 4 (depends on 3) The system of claim 3, further including a third forwardly facing nozzle having an outlet end disposed at said front end of said spray head. ### Claim 5 (depends on 2) The system of claim 2 wherein the spray head has a tubular passage in communication with the inlets of the nozzles, whereby said mixture is converged by the tubular passage prior to entering the nozzle inlets followed by divergence in said spray nozzles resulting in acceleration of said gas-liquid mixture to a supersonic velocity. ### Claim 6 (depends on 5) The system of claim 5, further comprising: a third forwardly facing nozzle having an outlet end disposed at a front end of said spray head; and a tapered end of said passage at said front end of the spray head in communication with the inlet of said third nozzle, whereby said mixture is converged by the tapered end prior to entering the inlet of the third nozzle followed by divergence in said third spray nozzle resulting in acceleration of said gas-liquid mixture to a supersonic velocity. ### Claim 7 (depends on 1) The system of claim 1, wherein said spray head further includes means for converging said gas-liquid mixture prior to entering the inlets of said spray nozzles, whereby convergence of said gas-liquid mixture followed by divergence in said spray nozzles results in acceleration of said gas-liquid mixture to a supersonic velocity. ### Claim 8 (depends on 7) The system of claim 7 wherein the converging means comprises said spray head having a tubular passage in communication with the nozzle inlets. ### Claim 9 (depends on 1) The system of claim 1, further including: an extension tube having a first end fixedly attached to an inlet end of said spray head, and a second end rotatably connected to said means for supplying said gas-liquid mixture to said spray head. ### Claim 10 (depends on 9) The system of claim 9, further including means for supporting said spray head and at least a portion of said extension tube within a hollow item to be sprayed. ### Claim 11 (depends on 1) The system of claim 1, wherein said means for rotating said spray head further includes means for simultaneously moving said spray head back and forth along a longitudinal axis of a hollow item to be sprayed. ### Claim 12 (depends on 11) The system of claim 11, wherein said means for rotating said spray head and for simultaneously moving said spray head back and forth comprises: a reversible drive motor having a rotatable output shaft; drive means connected between said output shaft and said extension tube; a threaded portion on an exterior surface of said extension tube; and a stationary threaded nut mounted on said threaded portion; whereby, rotation of said drive motor in a first direction causes rotation of said spray head and said extension tube in a first direction, and translation of said spray head in a first direction, and rotation of said drive motor in a second, opposite direction, causes rotation of said spray head in a second, opposite direction, and translation of said spray head in a second, opposite direction. ### Claim 13 (depends on 1) The system of claim 1, further comprising means for collecting waste liquid from within a hollow item after it has been sprayed, and means for analyzing the waste liquid to determine its contaminant level, and thereby determine the cleanliness of the hollow item. ### Claim 14 (depends on 1) The system of claim 1 wherein the liquid is supplied at a low flow rate. ### Claim 15 A system for cleaning and verifying the cleanliness of interior surfaces of hollow items including bottles, tanks, pipes and tubes comprising: a spray head containing first and second balanced, oppositely facing diverging cross section spray nozzles for accelerating a gas-liquid cleaning mixture to a supersonic velocity and impinging the same on the interior surfaces of a hollow item, said balanced, oppositely facing nozzles having longitudinal axes parallel to one another, but disposed at an angle relative to a longitudinal axis of said spray head, and having outlet ends disposed on first and second opposite side walls of said spray head, each said spray nozzle having an inlet and an outlet with the inlet having an area smaller than the outlet area, said spray head further including means for converging said gas-liquid mixture prior to entering the inlets of said spray nozzles, whereby convergence of said gas-liquid mixture followed by divergence in said spray nozzles results in acceleration of said gas-liquid mixture to a supersonic velocity at the outlet of the nozzle; means for supplying a gas-liquid mixture to said spray head; an extension tube having a first end fixedly attached to an inlet end of said spray head, and a second end rotatably connected to said means for supplying said gas-liquid mixture to said spray head; and means for simultaneously rotating and moving said spray head back and forth along a longitudinal axis of a hollow item to be sprayed. ### Claim 16 (depends on 15) The system of claim 15, wherein said spray head further includes a third, forwardly facing diverging cross section spray nozzle having an outlet end disposed at a front end of said spray head. ### Claim 17 (depends on 15) The system of claim 15, further including means for supporting said spray head and at least a portion of said extension tube within a hollow item to be sprayed. ### Claim 18 (depends on 15) The cleaning system of claim 15, wherein said means for simultaneously rotating and moving said spray head back and forth comprises: a reversible drive motor having a rotatable output shaft; drive means connected between said output shaft and said extension tube; a threaded portion on an exterior surface of said extension tube; and a stationary threaded nut mounted on said threaded portion; whereby, rotation of said drive motor in a first direction causes rotation of said spray head and said extension tube in a first direction, and translation of said spray head in a first direction, and rotation of said drive motor in a second, opposite direction, causes rotation of said spray head in a second, opposite direction, and translation of said spray head in a second, opposite direction. ### Claim 19 (depends on 15) The system of claim 15, wherein said first nozzle is generally forwardly facing relative to a front end of said spray head, and said second nozzle is generally rearwardly facing relative to the front end of said nozzle, whereby said second nozzle is particularly suited for spraying inlet areas of a hollow item when said spray head is positioned therein. ### Claim 20 (depends on 15) The system of claim 15, further comprising means for collecting waste liquid from within a hollow item after it has been sprayed, and means for analyzing the waste liquid to determine its contaminant level, and thereby determine the cleanliness of the hollow item. ### Claim 21 (depends on 15) The system of claim 15 wherein the converging means comprises said spray head having a tubular passage in communication with the nozzle inlets. ### Claim 22 (depends on 21) The system of claim 21, further comprising: a third forwardly facing nozzle having an outlet end disposed at a front end of said spray head; and a tapered end of said passage at said front end of the spray head in communication with the inlet of said third nozzle, whereby said mixture is converged by the tapered end prior to entering the inlet of the third nozzle followed by divergence in said third spray nozzle resulting in acceleration of said gas-liquid mixture to a supersonic velocity.