US2359380A - Jar seal - Google Patents

Description

Oct 3, 1944.

G. r- OSTROM JAR SEAL Filed Aug. 3, 1942 Patented Oct. 3, 1944 JAR SEAL Gustaf E. Ostrom, Whittier, Calif., assignor to Chemre Corporation, a corporation of Nevada Application August 3, 1942, Serial No. 453,305

2 Claims.

The invention relates to jar seals, and, although capable of various applications and adaptations, is of particular value in connection with closures for jars such as are employed for the canning or preserving of various foods, for example fruits and vegetables. The invention is of especial usefulness in connection with jars such as may be used for home canning.

The principal object of the invention is to provide a jar and closure therefor which can be made of materials readily available and which do not require the use of materials such as steel, tin or rubber, all of which, due to War conditions, are at the present time practically unobtainable. Further objects of the invention are to provide a seal or closure which does not require any special manipulative or other type of skill in order to produce a satisfactory seal, to provide a closure of such character that the ja may be opened with facility in order to obtain access to the contents thereof, and in general to provide a jar seal or closure which shall be simple and inexpensive to manufacture while being durable and efficient in use, and to provide an improved jar closure and seal of the character referred to.

In the accompanying drawing which discloses preferred embodiments of the invention,

Fig. 1 is a vertical section taken through the cap or lid;

Fig. 2 is an elevation, partly in section, of the jar to which the lid shown in Fig. 1 is to be applied;

Fig. 3 is an enlarged framgemtary vertical section of a portion of the jar and lid, showing the parts in the position occupied after the lid is dropped into position;

Fig. 4 is a view simila to Fig. 3, showing the relationship of the parts after the seal has been completed; and w Fig. 5 is a view similar to Fig. 3, but showing a slightly modified construction.

Referring to the drawing, it will be seen that Fig. 2 in general shows a jar H) of the so-called wide-mouth type, differing in construction from the usual wide-mouth jar in that the outer threads are not needed, while on the inside of the mouth of the jar adjacent the opening there is formed an internal lip or bead ll projecting inwardly of the outer lip l2 in such fashion as to form an internal upwardly presented groove 13 at the top of the neck or mouth of the jar.

Said groove l3 forms a pocket or seat for the lowe edge M of a peripheral flange l5 depending from the marginal edge of the lid l5, said lid l6 being manufactured of the same material, for example glass, as the material of which the jar I is formed or molded.

It will be observed that the outer surface of the depending flange of the cap is made with a circumferential depression I! for the purpose of accommodating and retaining the gasket 18, of a construction presently to be described, which is of such thickness that a slight space or tolerance as indicated at I9 is provided between the outer surface of gasket 18 and the inner surface 20 of the outer lip I2 of the-jar.

The gasket I8 is manufactured of slightly ductile or flexible material which, when heated to the required temperature, exudes a thermoplastic sealing material which flows by gravity into the crevice between the lower edge M of the lid and the surface of the groove l3.

The gasket or sealing ring I8 is preferably composed of any suitable foraminous, preferably infusible material, for example interwoven, braided, felted or otherwise interlocked fibers of any suitable more or less inert material such as mineral fiber, glass, wool, cotton, silk, rayon or other synthetic fibers or cellular material. This material, after having been formed into sheet or tubular form, is charged or loaded with such an amount of thermoplastic material having proper characteristics that, when the gasket or ring is heated to a temperature above that at which the thermoplastic material becomes fluid, the foraminous base is incapable of retaining all of the thermoplastic material with which it is charged or loaded, and therefore a portion of the liquid thermoplastic material will be released and will flow down thesurface of the ring until it fills the crevice as shown at 2| in Fig. 4.

The thermoplastic material with which the foraminous ring or gasket is charged should be of a waxy character, non-emulsifying and 'substantially solid at temperatures below 45 C However, above a temperature of about 50 C., it should begin to soften slightly as the temperature is raised until finally, at a temperature of C.- C., it melts substantially completely to form a viscous liquid.

It will be readily understood that this thermoplastic material should be of such character that it is resistant to the action of water, moisture,

. alcohol, dilute acids, vegetable oils and fats, or

anything else which is acid and should be odorless and non-poisonous, and that is not acted upon adversely by atmospheric agencies-r moisture, or anything which is generally contained in such foods which are canned or' preserved in glass jars. Synthetic waxes which will comply with these requirements are available on waxes which have a higher melting point than is desired. Also, some waxes now on the market possess all of the requirements without the necessity of combinining them with other waxes. For example, the Adheso wax having a melting point of between 90 C.95 0., made by the Glyco Corporation, is a synthetic wax which is very suitable for the purpose of my invention.

.In manufacturing the gaskets, the fibrous base, for example felted fibers, may be made up in the form of a sheet or in a tube. In the case of a sheet, rings of the required inside and outside diameter are punched out of a sheet about 1% of an inch in thickness and subsequently formed into the required cylindrical shape. If the material is made in the form of a felt tube, short sections of the required width are sliced off the end of the tube either by a suitable shear, or in a lathe, in which case it is not necessary to perform any further operation upon the thin felt cylinder thus made.

In any case, whether the ring is made from a sheet or from a tube, the ring may be charged with the thermoplastic material by making a saturated solution of the wax in toluene and then soaking the ring'in the solution, and then driving off the toluene which leaves the thermoplastic material contained in the interstices of the foraminous ring. Or, as may be preferable in most cases, the wax may be raised to a temperature well above melting point, and the felt rings may be immersed in the molten wax. In any case, care should be taken to see that the foraminous base is heavily charged with the thermoplastic material and that the interstices of the ring have been substantially completely filled with the wax,

The canning operation is effected in about the same way as in the case of the ordinary widemouth jar, home-canning operation in which a thermoplastic seal is employed. As customary in such operation, the fruit or other food is inserted in the jar, the lid with the plastic seal is loosely applied, and. after the required degree of sterilization at boiling water temperature has been effected, the jar is allowed to cool. It will be understood that the parts, including jar, lid and seal, reach a temperature of substantially the boiling point as a result of which the plastic synthetic wax will be liquified and will run down into the crevice, as indicated at 2| in Fig. 4.. When the jars and their contents are permitted to cool to room temperature, the seal 2| becomes sold and thus hermetically seals the jars.

In order to open the jar to gain access to the contents, an ice-pick Or knife or other sharp pointed instrument is thrust into the seal in the direction of the arrow 22, in order to break the seal and thus break the vacuum in the jar, whereupon the lid can be pried out with reasonable facility.

In Fig. 5, I have shown a slightly different modification which, from the standpoint of assembly or application of the sealing ring to the lid, possesses some advantage over the construction shown in Fig. 3.

As shown in said Fig. 5, the bottom li'p or bead which forms the lower edge of the recess I! has been eliminated, so that the sealing ring I 8a can be slipped on without expanding it to permit its application. It will also be observed that the lower edge of the sealing ring l8a directly contacts the surface of the groove itself, so that, when the wax congeals in the crevice between the lip I2a and the bead Ma, the seal will be, to a certain extent, reinforced by the fibrous structure of the sealing ring.

It will be manifest that gaskets made in accordance with my invention are capable of use in Ways other than I have specifically described. To a limited extent in connection with the embodiment shown in Fig. 5, and particularly where the gasket itself is subjected to considerable mechanical pressure, it may be advisable to stiffen or reduce the viscosity of the wax when it is in molten condition. This may be effected by adding to the wax a small percent, for example 1 to 5% of some very finely divided inert material such as talc, diatomaceous earth, or infusorial earth, or various clays, for example-bentonite. Bentom'te is particularly effective for this purpose, in view of the fact that its stiffening effect per unit of weight is very much more pronounced than in the case of ordinary papermakers China-clay or kaolin. Where bentonite is used, a material stiffening effect is produced when it is used in an amount of even less than 1% of the weight of the wax.

The scope of the invention should be determined by reference to the appended claims.

I claim:

1. In combination, a jar having a neck the outer end of which neck is provided with an annular upwardly presented groove, a rigid lid having a marginal depending flange having a vertical dimension greater than the vertical depth of said groove, a lower portion of said flange fitting within said groove when the lid is seated on the jar, a foraminous fibrous ring surrounding said flange and having upper and lower portions overlying portions of said flange which are respectively above and within said groove when the lid is seated on the jar, and thermoplastic material carried by said ring infusible at a temperature below normal atmospheric temperature but fusible at normal boiling water temperature and capable, when melted, of flowing into the crevice between the groove and the flange to form an impervious seal for the joint between the jar and the lid, said ring being of such vertical dimension that a portion thereof extends into the zone of the seal so as to reinforce the same, and another portion extends above the zone of the seal so as to protect the same.

2. In combination, a jar having a neck the outer end of which neck is provided with an annular upwardly presented groove, a rigid lid having a marginal depending flange having a vertical dimension greater than the vertical depth of said groove, a lower portion of said flange fitting within said groove when the lid is seated on the jar, a foraminous fibrous ring surrounding said flange and having a portion overlying at least a portion of said flange above said groove when the lid is seated on the jar, and thermoplastic material carried by said ring infusible at normal atmospheric temperature but fusible at normal boiling water temperature and capable, when melted, of flowing into the crevice between the groove and the flange to form an impervious seal for .the joint between the jar and the lid, said foraminous ring being disposed in overlying relation to the zone of the seal and substantially covering the same so as to be operative to protect the same against mechanical injury from extraneous sources.

GUSTAF E. OS'I'ROM.

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