US2300793A - Self-heating can - Google Patents

Description

Nov. 3, 1942.

V. E. C. MARTIN SELF HEATING CAN Filed March 22, 1941 rwawtofb WPG/L 5.0. MRT/N,

Patented Nov. 3, 1942 UNTTED STATES PATENT oIf'Flci-:f

AsrzLF-nrzlrrlrzd CAN y Virgil E. C. Martin, Merced, Calif. Applicationmreh ze, 1941, serial No. 384,736

3 Claims.

This invention relates to what may be termed a self-heating can of the type employing a. chemical vreaction between constituents, nor mally maintained separated indifferent compartments in the can, to produce heat for the remaining contents of the can, The present application is a continuation-impart of my prior application Serial No. 370,989, filed December 20, 1940.

In prior cans of this general type it has been common to employ a solid or granular material,

such as unslaked lime, and a fluid or liquid such nize that my invention is capable of other and different embodiments, and that the various demanner, but upon coming into contact with the surface portions of the material formed a 'thick paste which greatly impeded further penetration of the water or uid thereinto, with consequent loss of heating efficiency.

The present invention has been developed with the foregoing considerations in mind and accordingly has for its primary object toprovide such a self heating can wherein the lime or other granular or solid or powdered heating constituent is contained in a plurality of pads or packets so arranged relative to the inner can containing the material to be heated and to the compartment in which the water or other fluid is normally contained, as to permit an immediate thor ough saturation of said granular material or other solid or powdered heating constituent when the fluid is admitted thereto.

Further objects are: to provide in such a self tails thereof may be modied invarious ways all without departing from my said invention; therefore, the drawing and description herein are to be considered as merely illustrative and not as exclusive.

In the accompanying drawing:

Figure 1 represents a vertical section of the preferred embodiment of the invention, the same being taken on the line l-I of Figure 2, looking in the direction of the arrows;

, Figure 2, a transverse section on the line 2-2 of Figure 1, looking in the direction of the arrows;

Figure 3, a fragmentary front elevation of the preferred form of punch adapted for use with my invention;

Figure 4, a side elevation of in Figure 3; and

Figure 5, a plan` view of said punch.

Referring now'in Ydetail to the accompanying drawing, the letter A thereof designates, in its entirety, an outer can or container, divided interiorly by a transverse partition l into upper and lower compartments 3 and 2 respectively, the upper compartment 3 containing a food can or container B and having a plurality of relatively spaced longitudinally extending pads or packets D, and also preferably a lower transversely disposed pad or packet E, of unslaked the punch shown lime or other suitable granular or solid or powinto the upper compartment 3 when the can isv turned upside down and given a sharp blow on its bottom 5.

The outer container or can A may be of any suitable shape and is preferably of sheet metal construction, the preferred embodiment thereof having cylindrical sides or walls 4 and a top 6 and bottom 5 seamed or otherwise suitably secured thereto, as at 1 and I8 respectively.

The inner container or can B may be of the usual sheet metal construction having a cylindrical sheet metal side wall 9 and a top and bottom lli and Il respectively seamed or otherwise suitinvention, as by law required. However I recogably secured thereon. As shown in the draw- Also it is preferable, though not essential, to so position the inner container B that its upper end or top I projects exteriorly of and above the top of outer container A to be easily accessible for opening by means of the usual can opener.

Although the inner container B may be positioned in the foregoing manner by various means,

Vaexooms in the preferred form of the invention the outer can top 5 performs this function, the same being formed of annular shape and having an upstanding flange 8 around its inner periphery to receive and support the can B, said flange 8 preferably being seamed to the upper end of can 'B together with the top IU thereof, as at 25, to effectively seal the upper end of compartment 3.V

The pads or packets D and E of lime or other exothermically reacting solid or granular substance I4 may each be formed by enclosing the substance I4 in a suitably shaped permeable cas- Aing I2, which may be of cloth or fabric stitched or otherwise suitably joined at its edges, as at I3, the pads D preferably being oblong and the pad E being preferably disc shaped.

Any suitable number of pads D, four of such pads being shown in the drawing, may be disposed in a longitudinally extending direction around the inner can or container B, and as thus disposed will be transversely or circumferentially spaced from each other so as to leave a longitudinally extending fluid passage or channel or space I5 between each adjacent pair of such pads D, whereby fluid admitted to the upper compartment 3 from lower compartment 2 when the can is turned upside down and the partition I punctured, will readily pass along these passages I5 throughout the length of said pads D, surrounding and penetrating each of said pads D to react with the unslaked lime or other material contained therein.

In the preferred embodiment of the invention the pads D may be maintained in position by any suitable means, such as frictional engagement with the opposed can' sides 4 and 9 respectively, and the lower ends of said pads may rest on the lower edge beading I6 of inner container B to prevent longitudinal or downward displacement of said pads D. The lower pad E, which is preferably of smaller diameter than the outer can A and of such thickness relative to the space between partition I and can bottom II as to be freely vertically or longitudinally movable in said space, will normally rest on partition I; however when the entire self heating can is turned upside down to have its partition punctured to initiate the heating operation, the pad E will rest on the container bottom I I away from partition I so as not to interfere with or obstruct the passage of fluid into upper compartment 3.

The partition I may be of any readily puncturable preferably sheet metal material, such as thin sheet metal extending transversely across the can A and secured thereto in fluid tight fashion so as to positively prevent accidental leakage of fluid into compartment 3 and consequent premature reaction of the heating constituents. Obviously such a partition or seal I may be applied in various ways, though I propose forming the same as the bottom I of an inverted cup having cylindrical side walls I1 in contiguous engagement with the sides 4 of container A, and having its end edges, together with the edge portions of the container bottom 5, seamed in usual manner to the lower edge of container wall 4.

The punch I9 disposed in compartment 2 is.

suitably secured at its lower end, as at 20, to the medial portion of container bottom 5 and projects longitudinally upwardly with its pointed upper end or point 2| normally in lightengagement or near engagement with the partition I, so that when the self heating can of my invention is turned upside down and given a sharp blow adjacent the medial portion of bottom 5, preferably in registry with the lower end of punch I9. the flexible sheet metal or other sheet material can end 5 will yield medially towards partition I, thus permittingv the point 2| of said punch I9 to .puncture the partition I. v

Although various formsl of punch I9 may be successfully used, the pref 'rred form of punch I3 illustrated is particular -Iefficient and comprises a relatively thin cutting blade 22 having a sharp point 2| at its upper end to form a slit in the partition I, and a preferably integral substantially thick stiffening and reinforcing blade 24 disposed in a transverse plane relative to and longitudinally intersecting said cutting blade 22, said thick blade 24 terminating short of the point 2I of the punch and having rearwardly sloping blunt spreading or wedging edges 23 on either side thereof. Thus in the operation of such preferred form of punch I9, after the sharp point 2I has pierced the partition I and formed a narrow slit therein, the spreading edges 23 will engage and spread or wedge apart the opposite sides of the slit or puncture during continued insertion of the punch I9 therethrough, thus facilitating the rapid escape of fluid through said puncture.

In the operation of my invention, where it is desired to heat the material C in inner container B, the entire composite can or can assembly constituting my self heating can may be turned upside down and rested on the top of can B. The medial portion of can bottom 5 may then be given a sharp blow or blows to force punch I9 to pierce or puncture the partition I. This will permit the water from compartment 2 to enter compartment 3 flowing down around and between the pads D and pad E and serving to quickly and thoroughly saturate and react with the unslaked lime I4 contained in each said pad or packet. As a safety measure it is desirable to form one or more perforations in the bottom of container A to permit the release of any vapor pressure evolved by the chemical reaction. However it is conceivable that the chemicals or constituents used, and the proportions thereof, might be such as would not produce an objectionable amount of vapor pressure and accordingly under such conditions it would not be necessary to so perforate the can bottom 5. After the reaction has continued for a short time, roughly ten minutes or so, the food or other heated substance C contained therein will be steaming hot and the can may then be turned right side up and opened in the usual manner at the tcp I0. Furthermore, the chemical reaction will maintain the contents C of container B hot for a long period of time, for instance for an hour or more in the preferred embodiment of the invention.

Where the self contained punch I9 is omitted from the can structure, an ice pick, or nail, or other pointed instrument may be driven through the can bottom 5 and partition I at any point to start the heating action, however in such event it will be desirable to form the blade or operative portion of such instrument of just suil-l cient length to pierce the partition I, but shorter than the distance between the can bottoms and II respectively, thus making it impossible to inadvertently pierce the bottom II of the inner container or can B.

At the termination of the heating action when the can is turned right side up to be opened, the pad E will rest on partition I over the puncture formed therein and will prevent the escape of any substantial or undesirable amount of chemicals from the can compartment 3 back through the punctured partition I into lower compartment 2 and out of the can end or bottom 5 through any pressure relieving perforations that may have been formed therein.

Although I prefer to use unslaked lime, and water, disposed in the proper chemical proportions in compartments 3 and 2 respectively, as

the exothermically reacting components or constituents adapted to generate heat for the material C in container B, it will be obvious to those skilled in the art that various other chemicals or substances may be used in place of these preferred components or materials. Also it is thought to be apparent that my invention is adapted for use with components which when mixed with each other in upper compartment 3 will have an endothermic reaction serving to cool orrefrigerate the contents of inner container B.

I claim:

1. A self heating can comprising an outer container having longitudinally extending side walls and a top and bottom respectively seamed thereto, a transverse partition dividing said container into upper and lower compartments, an irmer container disposed in said upper compartment and spaced from said side walls and partition, a plurality of longitudinally extending relatively transversely spaced chemical heating pads disposed between the adjacent side walls of said inner and outer containers, and a transverse chemical heating pad normally resting on said partition and free to move; between said partition and inner container, in combination with a uid contained in said lowerf` compartment to react with said chemical pads', and means for releasing said fluid into saidgupper compartment comprising a punch attached to said container bottom in said lower compartment and having a pointed end projecting upwardly into near engagement with said partition to puncture the same when the said container bottom is given a sharp blow.

2. A self heating can comprising an outer container having longitudinally extending side walls anda top and bottom respectively secured thereto, a. transverse partition dividing said container into upper and lower compartments adapted to contain a plurality of heating pads and a fluid respectively, an inner container disposed in said vupper compartment and spaced from said side walls, in combination with a plurality of longitudinally extending heating pads disposed between said relatively spaced inner and outer containersin said upper compartment, said pads being arranged in such manner as to leave a longitudinally extending channel between each adjacent pair of pads.

3. A self heating can comprising an outer container having a, transversely extending resilient sheet material bottom, `a transverse partition disposed in said container and dividing the same into relatively longitudinally aligned upper and lower compartments, and a heating pad normally resting on the upper surface of said partition, in combination with a punch carried by and attached to the medial portion of said bottom with its operative pointed end in near engagement with said partition to puncture the same during upward movement of the medial portion of said bottom, said pad normally serving to cover the puncture thus formed.

E. C. MARTIN.

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