US2413497A - Form for use in building self-sealing containers for gasoline, etc. - Google Patents

Description

Dec. 31, 1946. R, NN

FORM FOR USE IN BUILDING SELF-SEALING CONTAINERS FOR GASOLINE ETC.

Filed June 12 1943 sf? aud Patented Dec. 31, 1946 UNITED STATE FORM FOR USE IN BUILDING SELF-SEALING CONTAINERS FOR GASOLINE, ETC.

Roy D. Heymann, New Hartford, Conn, assignor,

by mesne assignments, to Animal Trap Company of America, Lititz, Pa a corporation of Pennsylvania ApplicationJune 12, 1943, Serial No. 490,578

3 Claims.

This invention is concerned particularly with the manufacture, from so-calledsynthetic rubber or artificial rubber, of self-sealing cells for con; taining liquid fuel; although it is not limited to that field. Its purpose is to provide relatively inexpensive and easily constructed forms for use in the building of such cellsv and for analogous uses.

Having regard to the purposes above indicated, but without intending thereby to limitthe scope of the invention or the protection hereby claimed for it, I will now briefly describe the present usual tion, for withdrawal piece-meal from the form,

procedure of making, puncture-sealing cells and.

the formsemployed in connection therewith, as background, before describing the present invention.

The tanks in which the fuel supply of airplanes and some other self-propelled war engines is contained, are provided with linings or inner containers made of materials which are capable of closing punctures caused by bullets and projectiles. Generally the material of which such linings or containers are made is one of the socalled synthetic or artificial rubber compositions which are largely inert to the action of gasoline and oils. In the case of large tanks a number of separate containers or cells are placed within the tank structure in intercommunication. The term cell is here used as a generic term to include all units which are used either singly or in multiple as the primary containers for gasolene, etc., in the environment indicated. Such cells may have more or less irregular shapes and contours suited to the limitations of the spaces in which they are located. They are customarily built out of strips or sheets of the rubber composition in plastic condition, laid on the exterior of a form which has the required contours of a given cell, so as to envelop the form. Adjacent edges of the component sheets and pieces are overlapped, or abutted and overlaid by tapes, to

make a continuous fabric. The plastic structure thus fabricated is cured under heat to elastic firmness while still surrounding the form.

In most cases the cells made in this way envelop the forms except for an opening of smaller dimensions than those of the largest side or the cross section of the form, wherefore the form cannot be withdrawn as a unit from the finished cell but must be dismembered into parts small enough to pass through the opening. Previously two types of forms capable of being reduced to disconnected pieces have been used. The forms of one of these types are made of wooden sections capable of being taken apart, without destrucand of being afterwards reassembled for repeated use. Such forms, however, are very expensive to build, and they are large and heavy, running to a weight ofv 1,000 pounds or more when designed for making cells of large dimensions. They 'are also unable to withstand the effect of heat used for'curing the sheet material and warp. Thus, even though capable of repeated use, the number of usesi'sverylimited, as warping prevents disassembled pieces from being correctly put together-and alters the dimensions and shape of the entire form. H I

vForms of the other type 'are'made of plaster of Pariscastin molds'to therequired contours and dimensions. They also are expensive to make and are even heavier than the wooden forms. They are incapable of repeated'use, for each form must be broken up after the cell has been cured in order to permit removal from the cell, and once broken the form is useless and the material is worthless.

In accordance with the present invention, I have provided forms made of pulp material to serve the purpose indicated. The pulp used may be of any of the grades and compositions suitable for making paper. It may be composed of variable proportions of chemical and mechanical pulp, for instance from 30% to 40% of chemical pulp and 70% to of mechanical pulp.

The pulp is cast in a hollow foraminous mold, being delivered to the mold in a water suspension containing enough water to make it flow freely. It is continuously supplied to the mold under a pressure head, while the water continuously seeps through the multitudinous perforations in the lining of the mold and through the accumulation of fibers on the inner surface of the mold lining until the walls of the casting have been built up to a thickness sufficient to withstand the forces applied in building up a tank cell. Owing to the pressure applied to the entering pulp, and the impedance to escape of water through the small perforations in the mold walls, fibers are lodged against all of the interior surfaces of the mold to nearly uniform thickness throughout. Such thickness is determined and regulated by the length of time that pulp is delivered. When enough pulp has been thus delivered to make walls of the desired thickness, the pulp supply is shut off and air admitted under suflicient pressure to compact the deposited fibers and expel free water.

If desired, the air supply may be continued long enough, and may be heated additionally, to

evaporate the residual water while the pulp deposition remains in the mold. Or the pulp casting may be removed while still damp and otherwise dried. It will be understood that the molds provided for this use are sectional and built of a sufiicient number of disconnectible parts with parting lines between them suitably arranged to permit disassembling and removal from the casting without injury to the latter.

The pulp is beaten sufiiciently to make a uniform suspension of fibers and water and to hydrate the fibers enough to cause them to mat and felt together firmly in the mold. 'Diffierent degrees of hydration may be imparted to the different kinds of fibers in the mixture. Precise details of duration of beating are not of the essence of this invention, for considerably wide variations are possible, and any fibers and modes of treatment which will produce firm, tough and strong castings, are within the scope of the invention.

The result of the procedure thus described is a hollow form, of which a typical example is shown in the drawing. In the drawing- I Figure 1 is a perspective view of the exemplary form.

Figure 2 is a cross section thereof on the line 2-2 of Figure 1.

The form as a whole is designated by the reference letter a. It may have an opening b at any point desired in any of. its walls, or maybe made, without any opening. The dimensions, proportions and contours of the form are complemental to the interior dimensions, etc., of the mold in which it is cast, and may be of any values required for the cell to be made on the form.

This form, like those previously used, must be removed in fragments after the tank cell has been completed and cured. But little loss or waste is involved in thus destroying the form. The fragments can be returned to the beater for reconversion to pulp or, if this is not feasible, they, can be applied to other uses as, for instance, fuel to generate steam power or heat. They are much less expensive to make than forms of comparable dimensions of the prior types and have only a small fraction of the weight of such forms.

WhatI claim and desire to secure by Letters Patent is:

1. A form for use in the manufacture of selfsealing tank cells, consisting of a unitary hollow body of felted fibers such as are suitable for making paper.

2. A hollow form constructed of interfelted paper pulp fibers with the dimensions and contours of the interior of a prescribed self-sealing tank cell, the walls of said form being integrally united at their junctions by the 'constituent fibers of the structure and being of suitable thickness and stiffness to support sheets of vulcanizable composition and to withstand Without permanent deflection the pressures applied to effect adhesion ofoverlapping portions of such sheets.

3. A form for use in the fabrication of hollow articles of vulcanizable compositiomsaid form consisting of a unitary hollow body of felted

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