BG20404A3 - - Google Patents
Info
- Publication number
- BG20404A3 BG20404A3 BG14760A BG1476070A BG20404A3 BG 20404 A3 BG20404 A3 BG 20404A3 BG 14760 A BG14760 A BG 14760A BG 1476070 A BG1476070 A BG 1476070A BG 20404 A3 BG20404 A3 BG 20404A3
- Authority
- BG
- Bulgaria
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/16—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation
- F28D7/1615—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation the conduits being inside a casing and extending at an angle to the longitudinal axis of the casing; the conduits crossing the conduit for the other heat exchange medium
- F28D7/1623—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation the conduits being inside a casing and extending at an angle to the longitudinal axis of the casing; the conduits crossing the conduit for the other heat exchange medium with particular pattern of flow of the heat exchange media, e.g. change of flow direction
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/0041—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for only one medium being tubes having parts touching each other or tubes assembled in panel form
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
- F28F1/14—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending longitudinally
- F28F1/22—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending longitudinally the means having portions engaging further tubular elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
- F28F21/062—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material the heat-exchange apparatus employing tubular conduits
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/007—Auxiliary supports for elements
- F28F9/013—Auxiliary supports for elements for tubes or tube-assemblies
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/04—Arrangements for sealing elements into header boxes or end plates
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/04—Arrangements for sealing elements into header boxes or end plates
- F28F9/06—Arrangements for sealing elements into header boxes or end plates by dismountable joints
- F28F9/08—Arrangements for sealing elements into header boxes or end plates by dismountable joints by wedge-type connections, e.g. taper ferrule
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/4935—Heat exchanger or boiler making
- Y10T29/49377—Tube with heat transfer means
- Y10T29/49378—Finned tube
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Geometry (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Connection Of Plates (AREA)
- Rigid Pipes And Flexible Pipes (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19691926187 DE1926187A1 (en) | 1969-05-22 | 1969-05-22 | Heat exchange element made of materials with low thermal conductivity and strength |
DE19691937783 DE1937783B2 (en) | 1969-05-22 | 1969-07-25 | HEAT EXCHANGER ELEMENT FOR PARTITION WALL HEAT EXCHANGER |
DE19691948407 DE1948407A1 (en) | 1969-05-22 | 1969-09-25 | Heat exchange element made of materials with low thermal conductivity and strength |
Publications (1)
Publication Number | Publication Date |
---|---|
BG20404A3 true BG20404A3 (en) | 1975-11-05 |
Family
ID=27181942
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
BG14760A BG20404A3 (en) | 1969-05-22 | 1970-05-22 |
Country Status (12)
Country | Link |
---|---|
US (1) | US3648768A (en) |
JP (1) | JPS4930180B1 (en) |
BE (1) | BE750699A (en) |
BG (1) | BG20404A3 (en) |
CH (1) | CH517281A (en) |
CS (1) | CS174119B2 (en) |
DE (3) | DE1926187A1 (en) |
FR (1) | FR2043609B1 (en) |
GB (1) | GB1311998A (en) |
NL (1) | NL7005449A (en) |
RO (1) | RO61351A (en) |
YU (1) | YU33418B (en) |
Families Citing this family (79)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4098331A (en) * | 1974-10-07 | 1978-07-04 | Fafco, Incorporated | Solar heat exchange panel and method of fabrication |
DE2454086C3 (en) * | 1974-11-14 | 1981-07-16 | Liebherr-Verzahntechnik Gmbh, 8960 Kempten | Feeding device for workpieces |
DE2528267A1 (en) * | 1975-06-25 | 1977-01-20 | Buderus Eisenwerk | DEVICE FOR TRANSFERRING SOLAR ENERGY TO A LIQUID MEDIUM |
FR2329962A1 (en) * | 1975-11-03 | 1977-05-27 | Applimo Applic Thermo Elec | Indirect gas heat exchanger - has tubes in plate form wound round transverse buspipe leaving passage for other gas |
DE2618827A1 (en) * | 1976-04-29 | 1977-11-17 | Bruno Riech | SOLAR PANEL |
FR2362358A1 (en) * | 1976-08-18 | 1978-03-17 | Hamon Sobelco Sa | HEAT EXCHANGER WITH EXCHANGE WALL FORMED BY FLEXIBLE TUBES |
US4043015A (en) * | 1976-08-18 | 1977-08-23 | Brazeway, Inc. | Method of forming a header assembly |
JPS54101539A (en) * | 1978-01-27 | 1979-08-10 | Kobe Steel Ltd | Heat exchange pipe for use with water-sprinkling type, panel-shaped, liquefied natural gas evaporator and combination of such pipes and their manufacturing method |
CH625611A5 (en) * | 1978-03-15 | 1981-09-30 | Sulzer Ag | |
US4178909A (en) * | 1978-05-01 | 1979-12-18 | Reynolds Metals Company | Solar collector |
FR2441821A1 (en) * | 1978-11-15 | 1980-06-13 | Collard Et A Trolart Sa G | Parallel heat exchanger tubes - have liquids circulating in opposite directions and are held apart by welded longitudinal web |
US4381764A (en) * | 1980-03-20 | 1983-05-03 | Warren Wojcik | Solar panel |
FR2481433B1 (en) * | 1980-04-24 | 1985-06-28 | Armines | FLEXIBLE TUBE HEAT EXCHANGER |
US4341346A (en) * | 1980-07-30 | 1982-07-27 | Alcan Aluminium (U.K.) Ltd. | Radiators for use in hot water central heating systems |
US4414960A (en) * | 1982-05-10 | 1983-11-15 | Insolar, Inc. | Solar collection mat element |
JPS59186621A (en) * | 1983-04-05 | 1984-10-23 | Ngk Insulators Ltd | Porous body |
USRE33013E (en) * | 1983-04-05 | 1989-08-08 | Ngk Insulators, Ltd. | Multi-channel body |
GB2158215A (en) * | 1984-04-26 | 1985-11-06 | Fook Chong Chai | Cooling plant |
DE3512874C2 (en) * | 1984-05-17 | 1995-04-20 | Heidenau Netz & Seil Veb | Flexible heat transfer element |
EP0168558B1 (en) * | 1984-07-18 | 1990-01-31 | Akzo Patente GmbH | Method and apparatus for making heat and/or matter exchangers comprising tubes |
NO155069C (en) * | 1984-10-17 | 1987-02-04 | Norsk Hydro As | AID PROFILE, ITS USE IN HEAT EXCHANGERS AND PROCEDURES IN MANUFACTURING. |
US4603731A (en) * | 1984-11-21 | 1986-08-05 | Ga Technologies Inc. | Graphite fiber thermal radiator |
FR2592468A1 (en) * | 1985-12-26 | 1987-07-03 | Moureau Georges | Exchanger for the concentrating of solutions and various liquids |
US4832119A (en) * | 1986-06-05 | 1989-05-23 | Bloor Trevor J | Multi-tube heat exchanger and connectors therefor |
FI80234C (en) * | 1988-07-05 | 1990-05-10 | Uponor Nv | Apparatus for the manufacture of lattice structures |
FR2665510B1 (en) * | 1990-08-03 | 1992-12-04 | Fondeur Francois | SEALED CONNECTION METHOD AND CORRESPONDING SEALED CONNECTION. |
DE4033373C2 (en) * | 1990-10-18 | 1996-04-25 | Mannesmann Ag | Trolley |
DE4122400B4 (en) * | 1990-10-18 | 2004-04-15 | Siemens Ag | trolley |
GB9211413D0 (en) * | 1992-05-29 | 1992-07-15 | Cesaroni Anthony Joseph | Panel heat exchanger formed from tubes and sheets |
JPH06117790A (en) * | 1992-10-06 | 1994-04-28 | Sanden Corp | Heat exchanger |
JPH0755384A (en) * | 1993-08-19 | 1995-03-03 | Sanden Corp | Multi-tube heat exchanger |
JPH07310992A (en) * | 1994-05-16 | 1995-11-28 | Sanden Corp | Multi-pipe type heat exchanger |
FI106983B (en) * | 1997-01-20 | 2001-05-15 | Hadwaco Ltd Oy | Heat transfer elements in a film evaporator or distillator and process for its preparation |
FR2785375B1 (en) * | 1998-10-28 | 2001-01-12 | Valeo Thermique Moteur Sa | HEAT EXCHANGER WITH TUBE BEAM AND COLLECTORS IN THERMOPLASTIC MATERIAL |
US6364008B1 (en) | 1999-01-22 | 2002-04-02 | E. I. Du Pont De Nemours And Company | Heat exchanger with tube plates |
WO2000079206A1 (en) * | 1999-06-22 | 2000-12-28 | Dupont Canada Inc. | Heat exchanger formed from tubes joined by simultaneous extrusion thermal bonding |
SE518089C2 (en) * | 1999-10-26 | 2002-08-27 | Tetra Laval Holdings & Finance | Device at a tube heat exchanger |
US6302197B1 (en) * | 1999-12-22 | 2001-10-16 | Isteon Global Technologies, Inc. | Louvered plastic heat exchanger |
KR100363969B1 (en) * | 2000-02-11 | 2002-12-11 | 엘지전자 주식회사 | Evaporator for Refrigerator And Method for Manufacturing Header of Evaporator |
FR2810731B1 (en) * | 2000-06-21 | 2003-09-26 | Valeo Thermique Moteur Sa | HEAT EXCHANGER WITH FLEXIBLE PLASTIC TUBES, ESPECIALLY FOR MOTOR VEHICLES |
GB0107107D0 (en) | 2001-03-21 | 2001-05-09 | Dwyer Robert C | Fluid to gas exchangers |
WO2002075220A1 (en) * | 2001-03-21 | 2002-09-26 | Robert Charles Dwyer | Air treatment units |
US6787116B2 (en) | 2001-05-02 | 2004-09-07 | Aquatherm Industries, Inc. | Overmolding insert for heat exchanger, process for manufacturing a heat exchanger, and heat exchanger produced thereby |
US6878334B2 (en) * | 2001-08-14 | 2005-04-12 | Carrier Corporation | Condensing heat exchanger formed of norbornene polymer |
US20030070752A1 (en) * | 2001-09-27 | 2003-04-17 | Kevin Bergevin | Method of manufacture for fluid handling barrier ribbon with polymeric tubes |
US6742576B2 (en) | 2001-09-27 | 2004-06-01 | E. I. Du Pont De Nemours And Company | Heat exchanger barrier ribbon with polymeric tubes |
US20030070751A1 (en) * | 2001-09-27 | 2003-04-17 | Kevin Bergevin | Method of manufacture for fluid handling polymeric barrier tube |
CA2409900C (en) * | 2002-10-29 | 2005-02-08 | Global Industries Holdings Ltd. | Flat water hose and hose connectors for flat water hose |
JP4180359B2 (en) * | 2002-11-29 | 2008-11-12 | カルソニックカンセイ株式会社 | Heat exchanger |
KR20040080830A (en) * | 2003-03-13 | 2004-09-20 | 엘지전자 주식회사 | Heat exchanger and manufacturing method thereof |
US7048037B2 (en) * | 2003-12-09 | 2006-05-23 | Mcnair Edward F | Geothermal heating and/or cooling apparatus and method of using same |
GR1004729B (en) * | 2004-01-02 | 2004-11-22 | Κωνσταντινος Σπυριδωνα Τραβασαρος | Heating body with copper water pipe structure welded to aluminium sheets by means of laser beam bundle |
US6997248B2 (en) * | 2004-05-19 | 2006-02-14 | Outokumpu Oyj | High pressure high temperature charge air cooler |
US20090025921A1 (en) * | 2005-09-27 | 2009-01-29 | Uponor Innovation Ab | Capillary Tube System |
US20070175468A1 (en) * | 2006-02-01 | 2007-08-02 | Vaughan William J Iv | Systems and apparatuses for solar water heating |
JP5216759B2 (en) | 2006-04-04 | 2013-06-19 | エフィシャント・エナジー・ゲゼルシャフト・ミット・ベシュレンクテル・ハフツング | heat pump |
US20080271874A1 (en) * | 2007-05-04 | 2008-11-06 | John Gietzen | Thermal energy exchanger |
US20080283046A1 (en) * | 2007-05-14 | 2008-11-20 | Chung Fu Hsu | Solar collector having integral structure |
US8191617B2 (en) * | 2007-08-07 | 2012-06-05 | General Electric Company | Syngas cooler and cooling tube for use in a syngas cooler |
US8240366B2 (en) * | 2007-08-07 | 2012-08-14 | General Electric Company | Radiant coolers and methods for assembling same |
US8333013B2 (en) * | 2008-10-07 | 2012-12-18 | Delphi Technologies, Inc | Continuous manufacturing process for metal-plastic hybrid heat exchanger |
US8893714B2 (en) * | 2009-02-12 | 2014-11-25 | Babcock Power Services, Inc. | Expansion joints for panels in solar boilers |
US8261567B2 (en) * | 2009-06-23 | 2012-09-11 | Hussmann Corporation | Heat exchanger coil with wing tube profile for a refrigerated merchandiser |
US20110308228A1 (en) * | 2010-06-18 | 2011-12-22 | General Electric Company | Fin and Tube Heat Exchanger |
US20130025819A1 (en) * | 2011-07-25 | 2013-01-31 | Tai-Her Yang | Close-loop temperature equalization device having single-flowpath heat releasing device |
DE102012005513A1 (en) * | 2012-03-19 | 2013-09-19 | Bundy Refrigeration Gmbh | Heat exchanger, process for its preparation and various systems with such a heat exchanger |
US9227353B2 (en) * | 2012-11-08 | 2016-01-05 | Solar Hydronics Corporation | Molding apparatus and method for operating same |
US10072901B2 (en) * | 2013-06-28 | 2018-09-11 | Schneider Electric It Corporation | Indirect evaporator cooler heat exchanger manufacturing method |
FR3028018B1 (en) * | 2014-11-04 | 2019-03-22 | Valeo Systemes Thermiques | HEAT EXCHANGE ELEMENT ADAPTED FOR EXCHANGE OF HEAT BETWEEN A FIRST AND A SECOND FLUID, AN EXCHANGE BEAM COMPRISING THE HEAT EXCHANGE ELEMENT AND A HEAT EXCHANGER COMPRISING THE EXCHANGE BEAM |
US20170045309A1 (en) * | 2015-08-11 | 2017-02-16 | Hamilton Sundstrand Corporation | High temperature flow manifold |
AT518986B1 (en) | 2016-10-07 | 2018-03-15 | Dipl Ing Thomas Euler Rolle | heat exchangers |
US11662148B2 (en) * | 2017-08-03 | 2023-05-30 | Mitsubishi Electric Corporation | Heat exchanger and refrigeration cycle apparatus |
CN109780893A (en) * | 2017-11-10 | 2019-05-21 | 王晋声 | A kind of metal fin heat exchange unit and the heat exchanger using it |
CN108645265A (en) * | 2018-05-17 | 2018-10-12 | 广东美的制冷设备有限公司 | Pipe wing monomer and heat exchanger, air conditioner with it |
CN108534395A (en) * | 2018-05-17 | 2018-09-14 | 广东美的制冷设备有限公司 | Heat exchanger and air conditioner with it |
CN108562176A (en) * | 2018-05-18 | 2018-09-21 | 广东美的制冷设备有限公司 | Heat exchanger and heat transmission equipment |
CN108592654A (en) * | 2018-05-18 | 2018-09-28 | 广东美的制冷设备有限公司 | Heat exchanger and heat transmission equipment |
CN111220007A (en) * | 2019-11-29 | 2020-06-02 | 四川金象赛瑞化工股份有限公司 | Heat exchange plate, heat exchanger, application of heat exchanger and washing cooling tower |
US11230964B2 (en) * | 2020-04-20 | 2022-01-25 | Caterpillar Inc. | Machine system having cooler with pack seal and header assembly for same |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2804284A (en) * | 1953-04-03 | 1957-08-27 | Griscom Russell Co | Heat exchanger |
US2788543A (en) * | 1954-07-28 | 1957-04-16 | Plastex Company | Apparatus for producing plastic pipe |
US3132691A (en) * | 1959-02-06 | 1964-05-12 | Babcock & Wilcox Co | Heat exchanger construction and thermal shield therefor |
US3277959A (en) * | 1964-08-12 | 1966-10-11 | Du Pont | Plastic tube heat exchanger and process of making |
US3438432A (en) * | 1967-06-26 | 1969-04-15 | North American Rockwell | Plastic heat exchanger with anti-buoyancy means |
-
1969
- 1969-05-22 DE DE19691926187 patent/DE1926187A1/en active Pending
- 1969-07-25 DE DE19691937783 patent/DE1937783B2/en not_active Withdrawn
- 1969-09-25 DE DE19691948407 patent/DE1948407A1/en active Pending
-
1970
- 1970-04-09 CH CH528870A patent/CH517281A/en not_active IP Right Cessation
- 1970-04-15 NL NL7005449A patent/NL7005449A/xx unknown
- 1970-04-28 US US32659A patent/US3648768A/en not_active Expired - Lifetime
- 1970-04-30 GB GB2075670A patent/GB1311998A/en not_active Expired
- 1970-05-15 YU YU01248/70A patent/YU33418B/en unknown
- 1970-05-19 JP JP45042795A patent/JPS4930180B1/ja active Pending
- 1970-05-21 BE BE750699D patent/BE750699A/en unknown
- 1970-05-21 FR FR7018408A patent/FR2043609B1/fr not_active Expired
- 1970-05-22 RO RO63427A patent/RO61351A/ro unknown
- 1970-05-22 CS CS3596A patent/CS174119B2/cs unknown
- 1970-05-22 BG BG14760A patent/BG20404A3/xx unknown
Also Published As
Publication number | Publication date |
---|---|
YU124870A (en) | 1976-06-30 |
JPS4930180B1 (en) | 1974-08-10 |
DE1937783A1 (en) | 1971-02-04 |
FR2043609B1 (en) | 1974-02-01 |
US3648768B1 (en) | 1983-10-18 |
DE1948407A1 (en) | 1971-04-08 |
BE750699A (en) | 1970-11-23 |
FR2043609A1 (en) | 1971-02-19 |
DE1926187A1 (en) | 1970-11-26 |
RO61351A (en) | 1977-01-15 |
DE1937783B2 (en) | 1977-12-29 |
NL7005449A (en) | 1970-11-24 |
YU33418B (en) | 1976-12-31 |
CH517281A (en) | 1971-12-31 |
GB1311998A (en) | 1973-03-28 |
CS174119B2 (en) | 1977-03-31 |
US3648768A (en) | 1972-03-14 |