# US 4,394,204 A · Method for heat sealing

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- Number: US 4,394,204 A
- Document ID: US4394204A
- Status: Granted
- Kind: A
- Application number: 06/170,052
- Filed: 1980-07-18
- Granted: 1983-07-19
- Earliest claimed: 1979-09-14
- Assignees: Reynolds Metals Company
- Inventors: James L. Hutcheson
- Web page: https://patentgrep.com/patent/US4394204A

## CPC

- B65B 51/146: {Closing bags}
- B29C 65/14: using wave energy {, i.e. electromagnetic radiation,} or particle radiation {(using mechanical waves B29C65/06; using ultrasonic waves B29C65/08; pressing means transparent to electromagnetic radiation B29C66/81267)}
- B29C 65/1445: {heating both sides of the joint}
- B29C 65/18: using heated tools
- B29C 65/305: {involving the use of cartridge heaters}
- B29C 66/0342: {Cooling, e.g. transporting through welding and cooling zone}
- B29C 66/1122: {Single lap to lap joints, i.e. overlap joints (B29C66/45, B29C66/472, B29C66/52272 take precedence)}
- B29C 66/43121: {Closing the ends of tubular or hollow single articles, e.g. closing the ends of bags (closing tube ends B29C57/10)}
- B29C 66/7373: {Joining soiled or oxidised materials}
- B29C 66/73921: {characterised by the materials of both parts being thermoplastics}
- B29C 66/8181: {characterised by the cooling constructional aspects}
- B29C 66/83221: {cooperating reciprocating tools, each tool reciprocating along one axis}
- B29C 66/91421: {of the joining tools}
- B29C 66/91431: {the temperature being kept constant over time}
- B29C 66/91645: {by steps}
- B29C 66/919: {characterised by specific temperature, heat or thermal flux values or ranges (specific electrical resistance values B29C66/81262)}
- B29C 31/004: {Arrangements for converting the motion of a material which is continuously fed to a working station in a stepwise motion}
- B29C 66/72321: {consisting of metals or their alloys}
- B29C 66/7234: {comprising a barrier layer}
- B29C 66/8226: {Cam mechanisms; Wedges; Eccentric mechanisms}
- B29L 2031/7128: {Bags, sacks, sachets (tea bags B29L2031/7122; medical bags B29L2031/7148)}
- B65B: MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING (bundling and pressing devices for cigars A24C1/44; devices for tensioning and securing binders adapted to be supported by the article or articles to be bound B25B25/00; applying closure members to bottles, jars or similar containers B67B1/00-B67B6/00; concurrent cleaning, filling and closing of bottles B67C7/00; emptying bottles, jars, cans, casks, barrels or similar containers B67C9/00)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

A method and apparatus for hermetically heat sealing flexible containers, and particularly pouch-like containers, is disclosed. A filled pouch is positioned between a pair of heated bars, with the bars being constructed and arranged to maintain a gap therebetween, such that pressure is not applied to the pouch. Thereafter, the pouch is positioned between a pair of chilled sealing bars and the chilled bars are constructed and arranged to apply sealing pressure to the edge of the pouch, where the edge region of the pouch is sealed and cooled. If desired, a plurality of gapped heated bar stations may be provided prior to the chill bar position.

## Claims

### Claim 1

In a method of forming a heat seal on the open end of a flexible container after filling of said flexible container and cleaning of said open end of said flexible container, said cleaning producing moisture on said open end of said flexible container, said flexible container comprising a pair of generally planar walls which have been heat sealed to one another, comprising positioning said open end of said flexible container between a pair of heated bars and subsequently positioning said open end of said flexible container between a pair of chilled bars the improvement comprising maintaining a sufficient gap between said heated bars such that no pressure is applied to said open end of said flexible container while said open end of said flexible container is positioned between said pair of heated bars, evaporating said moisture from said open end of said flexible container while said open end of said flexible container is positioned between said pair of heated bars and applying sealing pressure to said open end of said flexible container while cooling said open end of said flexible container while said open end of said flexible container is positioned between said pair of chilled bars to thereby provide a hermetic seal on said open end of said flexible container.

### Claim 2 (depends on 1)

The method of claim 1 wherein said heated bars are maintained at a temperature between about 212.degree. and 500.degree. F. (100.0.degree. and 315.5.degree. C.).

### Claim 3 (depends on 1)

The method of claim 1 wherein said chilled bars are maintained at a temperature between about 50.degree. and 100.degree. F. (10.degree. and 38.degree. C.).

### Claim 4 (depends on 1)

The method of claim 1 wherein said chilled bars apply a sealing pressure between about 10 and 100 pounds per square inch (7,031 to 70,310 kilograms per square meter) to said open end of said flexible container.

### Claim 5 (depends on 1)

The method of claim 1 wherein said gap between said heated bars is maintained between about 0.001 and 0.005 inches (0.00254 and 0.0127 centimeters) greater than the total thickness of said flexible container.

### Claim 6 (depends on 1)

The method of claim 1 further comprising positioning said open end of said flexible container between at least one additional pair of heated bars prior to said positioning said open end of said flexible container between said pair of chilled bars and maintaining a gap between said additional pairs of heated bars such that no pressure is applied to said open end of said flexible container prior to said positioning of said flexible container between said pair of chilled bars.

### Claim 7 (depends on 1)

The method of claim 1 wherein said additional heated bars are maintained at a temperature between about 212.degree. and 500.degree. F. (100.0.degree. and 315.5.degree. C.).

### Claim 8 (depends on 1)

The method of claim 1 wherein said gap between said additional heated bars is maintained between about 0.001 and 0.005 inches (0.00254 and 0.0127 centimeters) greater than the total thickness of said container.