US 3273743 A
Description (OCR text may contain errors)
Sept. 20, 1966 J c, MOCQLL 3,273,743
SEALING Filed NOV. 14, 1963 INVENTOR:
JOHN C. Mc Com.
BY (3, 5, zmwawmt ATTORNE s United States Patent 3,273,743 SEALING John Cameron McColl, Childwall, Liverpool, England, assignor to Rubbarite Limited, Liverpool, England, a British company I Filed Nov. 14, 1963, Ser. No. 323,706 Claims priority, application Great Britain, May 17, 1963, 19,634/ 63 4 Claims. (Cl. 220-46) The present invention is concerned with improvements in or relating to scaling, and in particular to scaling of a container having at least one removable lid, e.g. a cask, keg, drum or American pail.
Containers having removable lids are usually constructed such that the end of the body of the drum which is to receive the lid is curled over usually outwardly to form a lip and the edge of the lid is provided with a turned-over portion which forms round the perimeter of the lid a semicircular groove, known as a curl, which cooperates with the lip of the container.
Usually when such containers are used to carry or store materials, such as chemicals, 'a seal is provided between the lid and the end of the container to prevent escape of the material from the inside of the drum and also to exciude water and air as much as possible from the interior of the container. The seal is usually located in the curl of the lid such that when the lid is placed over the end of the container the seal lies between the curl of the lid and the lip of the container. When a closure band is applied to the container to force the lid and the container together the seal is compressed between the curl of the lid and the lip of the container, thus forming a seal between the lid and the container.
Such seals have been manufactured from a variety of materials including solid rubber, sponge rubber, expanded rubber, cotton, asbestos, cord and paper. The sealing member is generally made of rectangular cross-section and these sealing members tend to fall out of the curl of the lid when the lid is turned over to place it on the container. These sealing members of rectangular cross section may also become twisted when the lid is placed in position thus causing an imperfect seal between the lid and the container.
To overcome these problems it has been proposed to attach the seal into the curl of the lid by means of an adhesive, either flowed into the curl before the sealing member is placed into position or disposed on the back of the sealing member. The first of these two methods involves two processes usually with a time lapse in between since after the adhesive has been applied to the curl of the lid, it is normally necessary to allow the adhesive to partially gel before the sealing member is placed in position. The second method also involves two stages either removing a backing strip to uncover the adhesive and then placing the sealing member in the curl of the lid, or applying an adhesive to the back of the sealing member and then placing said sealing member into the curl of the lid. In all these methods involving the use of adhesive, the process of putting the seal in position is difficult due to the necessity of handling adhesive. Also such sealing members may become twisted when the lid is placed in position thus causing an imperfect seal.
It has also been proposed to use a sealing member of the same cross-section as the curl of the lid but such sealing members also require the use of adhesive to retain them in position in the curl of the lid when it is turned over. Further, such sealing members having the same cross-section as the curl of the lid are generally more expensive to produce than the rectangular cross-section sealing members.
3,273,743 Patented Sept. 20, 1966 Further, when the seal has to be fixed to the curl of the lid with adhesive, it is generally difiicult to remove the seal after use and when removed such a seal is not normally in a fit condition to be used again.
It has also been proposed to flow a rubber compound in a liquid state into the curl of the lid and then cure or age the rubber compound while it is in position so that the compound is retained in the lid. This method, however, usually involves the use of expensive machinery for applying and curing the compound, and in any event often the compound very quickly takes a permanent set with the result that leakage may occur.
It is now proposed to use a sealing member comprising a first layer of a resiliently deformable material of such a bulk density that it will conform to the shape of the curl and a second layer of a resiliently deformable material having a greater bulk density than said first layer. The sealing member fits into the curl such that the first layer is remote from the mouth of the curl and the second layer is in the mouth of the curl. On applying pressure to the sealing member the first layer conforms to the contour of the curl and the second layer Wedges in place in the curl.
According to the present invention therefore there is provided a sealing member, for a drum having a removable lid, said lid having a curl comprising, a first layer of a resiliently deformable material of such a bulk density that it will conform to the shape of the curl and a second layer of a resiliently deformable material having a bulk density greater than that of said first layer.
Further according to the present invention there is provided a drum comprising a removable lid having a curl, and a body having a lip, having a seal as described above disposed between said curl and said lip. The first layer is preferably narrower than the second layer, said second layer preferably being of the same width as the curl of the lid. The first layer generally has a cellular structure and is usually of an intercellular structure. The first layer may be composed of an expanded, preferably foamed, rubber or a cellular, preferably foamed, material selected from the class of compounds generally known as plastics, e.g. polyethers, polyesters or polyurethanes. The bulk density of said first layer is prefierably not greater than 5 lb./cu. ft. and more preferably has a bulk density of from 1 /2 to 2 lb./cu. ft. This first layer is preferably made of an expanded polyurethane of the polyether or polyester type.
These expanded polyurethanes maybe prepared by reacting a polyester of a po'lye-ther resin containing primary or secondary hydroxyl groups with an organic isocyanate containing one or more reactive N=@O groups and water in the presence of a suitable catalyst. The mixture is expanded into a cellular structure by carbon dioxide formed by reaction of the =isocyan'ate with water. The second layer may have the same chemical composition as the first layer but in general made from a rubber which may be a natural or synthetic rubber and is preferably a cellular rubber. An example of a preferred rubber which may be used is neoprene. The bulk density of the second layer is preferably no less than 10 lbt/cu. ft. and more preferably the second layer has a bulk density of from 16 to 45 lb-./cu. ft. Most preferably the bulk density of said second layer is from 30 to 45 lb./cu. ft.
The two layers may be composed of materials of the same chemical compositions or of materials of different chemical compositions. If the two layers are of different chemical composition, sheets of the two materials are first bonded together using any suitable adhesive e.g. a rubber adhesive, and then cut into strips. These the two layers have the same chemical composition, the two layers may be prepared in one operation and then the sheet out into strips and formed into sealing rings as previously described, or the two layers may be prepared separately and then bonded together as described above.
In order to prevent the adhesive used to bond together the two layers of material, and/or the two ends of the strips, from adhering to the lid and/ or the body of the drum, it is preferred that the sealing member is sprayed with a silicone fluid prior to use.
The invention will now be further illustrated by way of example and with reference to the accompanying drawing FIG. '1 of which shows a section of a drum sealing ring assembly and FIG. 2 shows an exploded view of the same assembly.
Referring to FIGS. 1 and 2, lid has a curl 4 formed in the periphery thereof. Sealing member 6 comprises a first layer 8 of a resiliently deformable material of such a bulk density that it will conform to the shape of the curl 4 and a second layer 10 wider than said first layer 8 said second layer 10 being composed of a resiliently deformable material having a bulk density greater than the bulk density of said first layer 8. Drum body 12 has a turned-over portion or lip 14 adapted to cooperate with the curl 4 of the lid 2.
To assemble the drum and seal, the seal 6 is pressed by hand into the curl 4 of the lid- 2. The lid 2 is then placed onto the body 12 of the drum such that the seal 6 is disposed between the curl 4 and the lip 14. The lid 2 is then pressed down on the body 12 thus deforming the seal 6 and forming a seal between the body 12 and the lid 2 of the drum. A closure means (not shown) is then applied to maintain the lid and drum in position until it is desired to break the seal. The preferred closure means is a closure band.
The invention will now be further described with reference to the following examples which are not intended to limit the invention in any way.
Example I A sheet of sponge rubber of thickness having a bulk density of 45 lb. per cu. ft. and hardness value of /20 lbs. per sq. inch at 25% compression, was bonded on to an expanded polyurethane sheet of A" thickness having a bulk density of 1 /2 to 1% lb. per cubic ft. and a compression set of 6% at 90% compression. The bonding agent was a two part cold curing synthetic/rubber/ resin.
The following mix was used to prepare the expanded polyurethane:
Polyether triol, polymer 100 Stannous cetoate 0.3 Water 3.6 Triethylene diamine 0.2 Silicone oil 1.5 Toluene di-isocy anate 46.0
The sponge rubber of this composite sheet was then subjected to a fine mist of silicone fluid, the silicone content being 100%.
The composite sheet was then cut by a strip cutter to a width calculated to be a fit into the greatest width of the curl of the lid to be sealed. This strip was then cut to a length suitable to fill the whole of the curl of the lid. The cutting of the ends being scarfed on identical angles. The ends were then solutioned with the adhesive as used above, so that the sponge or expanded rubber joined to itself and the plastic foam joined to itself, thereby forming a ring.
The ring seal thus made was placed in the curl of the lid, and pushed slightly into position by applying pressure by an identical lid. The lid was then placed on the body of the drum, and the closing band placed in position. When the closing band was removed the seal was firmly fixed in the lid, and did not come out of the curl when the lid was dropped on the floor from the height of 4 feet.
A tacky substance (rubber solution) was applied to the bead or top of the drum body where it would come into contact with the sponge rubber, and the drum was closed again, when the lid was removed no tack took place between the drum body and the seal owing to the silicone treatment described above.
Test for sealing: A 45 gallon drum (22 dia.) was filled with water. The lid (to which had been fitted the seal as described above) was placed in position and the closing band clamped in position. The drum was then inverted.- After 3 days the lid was removedno seepage or leakage had occurred. The lid was put back again and during 10 days no leakage took place. The lid was again removed, the seal extracted, examined, refitted, and retested. Again no leakage took place.
Example 11 The procedure of Example I was repeated using an expaned synthetic rubber sheet having a bulk density of 16/20 lbs. per cubic foot and a compression set of 10% at 40% compression and the expanded polyurethane described in Example I.
Example III The procedure of Example I was repeated using a sheet of sponge rubber of 3/16 thickness having a bulk density of 13 lbs. per cubic foot and an expanded polyurethane sheet of A" thickness having a bulk density of 2 /2 /3 lbs. per cubic foot. The bonding agent used was a two part cold curing synthetic/ rubber/ resin.
The following mix was used to prepare the expanded polyurethane.
Polyether triol 100.0
Silicone oil 0.6 Dibutyltin diacet-ate 0.1 N-ethyl morpholine 0.4 Tri ethylene diamine 0.2 Water 2.8 Tolylene di-isocyanate (/20 2,4-2,6 isomer) 36.6
It is to be understood that numerous variations in the composition of the mix used to prepare the polyurethane may be used and the above mix is only given by way of example.
The construction of the sealing ring made in accordance with the invention gives it a long and useful life, saves a considerable time in fitting, can be easily removed should the container need cleaning and so enables the container to be sold at a lower price. The heavier density material and/or the lighter density material can be of such quality to be suitable for containers in which are packed materials having a deleterious effect on natural rubbers. The seal made of different materials per se synthetics. ance than the normal methods employed.
Although the present invention has been described with reference to the specific details of certain embodiments thereof, it is not intended that such details should be regarded as limitations upon the scope of the invention except in so far as included in the accompanying claims.
1. The combination of a container lid having a peripheral curl of substantially semi-circular transverse crosssection and a sealing member disposed within said curl, said sealing member comprising a first layer composed of a resiliently deformable material having a bulk density of from 1 /2 to 2 lbs. .per cubic foot and a second layer composed of a resiliently deformable material having a bulk density of from 30 to 45 lbs. :per cubic foot, said sealing member being applied to said lid by pressing said member into said curl so that the first layer conforms to The seal described is much better in appear- 6 the contour of the curl and the second layer wedges in References Cited by the Examiner place in the opening of the curl. UNITED STATES PATENTS 2. The combination of claim 1 wherein the first layer 2,275,235 3/1942 Shankfin et a1 22O 46 is composed of resiliently deformable foamed polyure- 5 2,866,731 (12/1958 Van Epp 161 253 X thane and the second layer is composed of a resiliently 2,373,411 2 1959 Donaldson et 1, 220 4 X deformable cellular rubber. 3,126,591 3/ 1964 Hamilton 220-'46 X 3. The combination of claim 2 wherein said first layer FOREIGN PATENTS is narrower than said second layer.
. 4 8 19 0 G B t 4. The combination of claim 1 wherein the bulk density 0 2 x 2 x22 5533 of the first layer is from /2 to 5 lbs. per cubic foot and the bulk density of the second layer is 10 to 45 lbs. per THERON CoNDoNprimary Examine"- cubic foot. R. A. JENSEN, Assistant Examiner.