US2482665A - Hemispherical heating device - Google Patents

Description

Sept. 20, 1949. w. H. GEYER HEMISPHERICAL HE ATING DEVICE Filed Oct. 16, 1947 Y IN VEN TOR. v Will/run H. G'eyer fiTTORNEY Patented Sept. 20, 1949 HEMISPHERICAL HEATING DEVICE William H. \Geyer, Nutley, N. .J., assignor to .Gyco Instruments, lne Bloomfield, N. J., a corporation of New Jersey Application October 16, 1947, Serial No. if-80,199

4 Claims. '1

This invention relates to electricalheating devices and more particularly to hemispherical electrical heating devices for spherical containers such as spherical chemical laboratory apparatus comprised of glass and known in the art as flasks.

The object of the invention is to provide an improved hemispherical electrical heating device.

Another object is to provide a hemispherical electrical heating device adapted to be sustained in heating position about a spherical flask without straining the said flask or means independently sustaining said flask.

Still another object is toimpart semi-rigidity to a non-rigid hemispherical heating device for spherical containers.

Other objects will be apparent as the invention is further hereinafter disclosed.

Heretofore in the art, such as :is shown by .Morey Patent No. 2,231,506, it has been proposed to provide an electrical heating device for hemispherical containers which consists of the combination of two hollow hemispherical members each having a construction consisting of flexible inner and outer Walls comprised of a plurality of layers of a flexible fireproof fabric with fibrous insulating material the-rebetween and with a heating element disposed between a plurality of layers of the inner wall of the hemispherical members.

Such a flexible construction, however, has certain deficiencies, which it is the object of this invention to overcome, one of which deficiencies is that in most instances the hemispherical container about which the heating device is disposed is generally suspended by a support means normally engaging the neck of the container at an elevation above the horizontal level of a laboratory desk or table and a support means for the heating device usually must be employed to sustain the weight of the heating device in position about the flask to relive the flask and sustaining means therefor from the strain incidentto the weight of the said heating device. The non-rigid structure of the heating device of the said Morey Patent No. 2,231,506 does not lend itself readily to be sustained in this strain-free manner.

In loo-pending application b William O. Geyer et'al bearing Serial No. 6.65367 filed April ,27,

1946, and entitled Electrical heating device, is

described and claimed an improvement on the Morey-type heating device wherein the heating element, instead of being disposed between the plurality of layers comprising the inner flexible wall of the device, is disposed upon the exterior face of the inner flexible wall and consists of a flexible wovenstrip containing a warp or weft thread consisting of .an electrical resistance wire, saidstr-ip being formed into a helical hemispherical :coi-l for attachment to the flexible inner wall of the said device. This improvement overcomes the heating deficiency of the .Morey device incident to the location of the heating element of this device between the plurality of layers comprising the inner wall requiring the heater element to be operated at an overload current to overcome the obstruction to the passage .of heat energy from the heater .element to the flask presented by the thermal insulation of the interposed layers-of the said flexible inner wall.

In the present invention, the heating device of said Geyer et al., invention is further improved by the provision of an internally disposed resilient frame centrally located between the inner and outer flexible walls of the device and surrounded and enclosed by the fibrous heat insulating material disposed between the said inner and outer flexible walls of the device and functioning to impart to the flexible heating device a resilient semi-rigid structure adapting the device to be sustained in position about the flask with the flexible hemispherically shaped heater element thereof in closeaspaced position to the outer surface of the flask Without imposing a strain on the flask or on the flask sustaining means.

The internal resilient frame improvement of the invention may be constructed in a plurality of shapes and designs without essential departure from the invention, as one skilled in the art will recognize. As one specific embodiment of the invention, but not as a limitation thereof, I have illustrated in the drawings one preferred form of internal rigid frame.

In the drawings:

Fig. .1 is .a side elevati-onal view, partly in section, of a spherical-type heating device for glass flasks and the like, improved in accordance with the present invention by the incorporation therein of an internal rigid frame of a preferred type;

Fig. '2 is a perspective view of the improvement feature of the present invention;

Fig. 3 is an enlarged sectional view illustrating one feature of construction of the same;

Fig. 4 is an enlarged View of a Section of the flexible strip forming the spiral woven heater element employed in the device; and

Fig. 5 is a schematic wide elevational view of the spiral woven heater element of the said device.

Referring to the drawings, the improvement feature of the present invention is applied exclusively to the lower hemispherical part A of the dual heater device A and B, the upper part B of which does not require such improvement.

The improvement of the present invention consists of internal resilient frame member F disposed substantially centrally within fibrous 1nsulation I filling the space gap between inner and outer flexible walls W and W comprised of woven insulating material such as glass Wool or asbestos or mixtures thereof, of the lower part A of heating device A--B.

Frame member F, in the specific embodiment illustrated, is comprised of flexible strip material shaped in an open basket-weave in the manner indicated, to a hemispherical form conforming in diameter and height to the size f the hemispherical part A of the heater device AB at the point of disposition therein. Instead of two (2) semi-circular strips a,b depending from circular strip 0, as shown, three (3) or more such semi-circular strips may be used without departure from the invention.

Preferably, the strip material comprising frame F consists of one of the well known types or kinds of heat-resistant spring material so that the frame F has a certain degree of resiliency and give such that when a force is applied against the bottom of part A to press the part A upwardly against the bottom of spherical container C, which normally is rigidly sustained in position by a clamp means (not shown) engaging the neck of container C, the flexibility of frame F absorbs any strain impressed upon the container C or upon the support or sustaining means therefor.

The spring material employed in the forming of frame F may consist of metal,s1lch as spring steel or any other type or kind of heat-resistant sprin material, such as one of the high temperature organic plastics, for example those known generally in the art as a phenolic resin. Where spring metal is employed it is preferable to enclose the strip with a woven dielectric cover (1, as indicated in Fig. 3, and to assemble the parts a, b and together by means of rivets 1', substantially as shown. Alternative means for securing the parts a, b and 0 together may be employed without departure from the invention.

Referrin to Figs. 1, 4 and 5, the details of the heating element H are shown. This heating element I-I consists of a flexible woven strip consisting of warp threads [0 and a weft thread H, the warp threads I0 consisting of fibrous dielectric material such as glass wool or asbestos fibers, or mixtures thereof, and weft thread H consisting of a metallic filament comprised of an electrical resistance alloy the specific composition of which may Vary widely without essential departure from the invention and, per se, forming no part of the invention, the said weft thread I I having a woven or other type cover or surface coating l2 thereon consisting of dielectric material electrically insulatin the weft thread i l. Preferably weft thread H consists of an electrical resistance alloy of the type commonly known in the art as Nichrome or nickel-chromium alloy.

Preferably the woven strip H is preformed into hemispherical form, such as indicated in Fig. 5, the size thereof substantially conforming to the size of the hemispherical recess in heater A provided by the exterior surface of inner wall W thereof, to which exterior face W the preformed strip H is to be secured by means of stitchings, using thread comprised of glass wool.

It is believed apparent from the construction shown in the drawings that by the location of the resilient basket support member F centrally within the insulating fibrous packing material filling the space gap between inner and outer flexible walls W and W any pressure applied against the outer wall W in a direction urging the heater part A inwardly against the container C will be intercepted by member F and equalized or distributed throughout part A with any reverse strain imposed by the container rigidity or rigidity of the support means therefor absorbed by the packing material interposed between the support member F and the inner wall W thereby locating heater element H in a position closely conforming to the exterior surface of container C.

Many modifications and adaptations of the invention will occur to those skilled in the art from the above disclosure of the invention and from the specific embodiment thereof illustrated in the drawing and. all such are contemplated as may fall within the scope of the following claims:

What I claim is:

1. A hemispherical heating device for spherical containers, said device comprisin in combination spaced apart, flexible hemispherical, inner and outer walls comprised of woven fibrous ma terial having high thermal and electrical insulating properties, a packing consisting of fibrous material of high thermal and electrical insulating properties filling the space gap between said walls, a flexible electrical resistance heating element secured to the exterior surface of the said inner hemispherical wall, and a hemispherical resilient support member disposed centrally within the said packing between the said spaced apart, flexible hemispherical inner and outer walls.

2. The combination of claim 1, wherein said hemispherical support member consisting of an annular part and two hemispherical parts, the said hemispherical parts being joined at their ends to the annular part at substantial right angles to each other, each said part consistin of flexible strip material the composition of which is resistant to heat.

3. The combination of claim 2, said strip material consisting of metal the surface of which is covered with dielectric insulating material.

4. The combination of claim 2, each said part consisting of spring strip material consisting of a metallic composition, said strip material having dielectric insulation covering over the surface thereof.

WILLIAM H. GEYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,020,588 West Mar. 19, 1912 1,492,146 Thornton, Jr. Apr. 29, 1924 1,657,479 MacFarland Jan. 31, 1928 2,231,506 Morey Feb. 11, 1941

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