US2643324A - Electric heating device - Google Patents

Description

June 1953 H. H. GOLDSTAUB 2,643,324

ELECTRIC HEATING DEVICE Filed Sept. 19, 1951 5 Sheets-Sheet l June 23, 1953 H. H. GOLDSTAUB ELECTRIC HEATING DEVICE Filed Sept. 19, 1951 5 Sheets-Sheet 2 5 Sheets-Sheet 5 Filed Sept. 19, 1951 9 Lieu-rue. v r I l'l/VZ l Eldfkt 01.03780!!- 5,:

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June 23, 1953 Flled Sept 19, 1951 H. H. GOLDSTAUB ELECTRIC HEATING DEVICE June 23, 1953 5 SheetS Sheet 5 Filed Sept. 19, 1951 Patented June 23, 1953 UNITED STATES PATENT OFFICE ELECTRIC HEATING DEVICE Heinz Herbert Goldstaub, Snaresbrook, England Application September 19, 1951, Serial No. 247,219

4 Claims.

known as side entry or multi entry types,

that is to say, with an opening at the side with or without an opening at the top or a number of openings, not necessarily of the same size, be easy of application to the flask and hold on the flask without extraneous means.

Heating devices have previously been known made of woven glass fabric in association with metallic heating wires, but these could not as a single unit be applied to'h'eat the external surface of flasks of non-uniform diameter, beyond their maximum. diameter.

'In designing a heater in which heat loss over substantially the whole of the external surface of a vessel is prevented there are two possibilities or groups, namely, one in which heating is only effected up to the maximum diameter from the bottom and the other in which heating is applied substantially all over the vessel. Previously it was only possible to apply heat substantially all over the vessel by dividing the heating mantle into two parts at the maximum diameter. In accordance with the present invention by providing an extensible or elastic type of heater over the upper and lower parts, a unit can be provided for heating over substantially the whoie external surface of the vessel.

In brief the invention consists in an electrical heating device for a vessel, comprising a flexible mantle made of knitted heat resisting and electrically insulating fibres, marginal portions in said mantle defining an opening, elastic means sur rounding said opening, and an electrical heating coil associated with said mantle, said opening being smaller than a part of the vessel with which the mantle is to be in contact, whereby the elastic means may be stretched to pass over said part and can grip said vessel.

For a better understanding of the invention and to show how the same may be carried into cifect, reference will now be made to the accompanying drawings in which:

Figure 1A is a vertical. section illustrating a first embodiment,

Figure 1B is a horizontal section corresponding to Figure 1A,

Figure 1C is an enlarged detail of part of the embodiment illustrated in Figures 1A and 1B,

Figure 1D is a view of the embodiment i1lustrated in Figure 1A at an intermediate stage of manufacture,

Figure IE is a view, similar to Figure 1A, illustrating a modified first embodiment,

Figure 2 is a view, similar to Figure 1A, trating a second embodiment,

Figure 3 is a view, similar to Figure 1A, trating a third embodiment,

Figure 4 is a view, similar to Figure 1A, trating a fourth embodiment, and

Figure 5 is a View, similar to Figure 1A, illustrating a fifth embodiment.

Referring now to the drawings, the round bottom flask'l (see Figure 1A) has a single neck, and is covered by a flexible heating mantle which contains a heating coil 3a and 3b of electric resistance wire, the part 3a being spirally wound, whilst the part 3b is wound in zig-zag form. The part 311 covers the lower half of the flask up to its maximum diameter, whilst the part 3b covers the upper half of the flask. It will be apparent that the zig-zag form of part 3b has greater extensibility than the spirally-wound part 3a.

The heating mantle may be produced from an open-ended tube 1 (see Figure ID) of knitted glass fabric, the tube having draw cords 8 and 9 at its ends. The knitted structure S of the fabric is apparent from the enlarged detail in Figure 1D. The draw cord 8 is pulled tight and knotted and the tube I is placed over a former 4| to produce the shape shown in Figure 1D. The heating coil 3a, 3b is then sewn to the fabric of the tube 1 and the free end of the tube 7 folded over so that a recess for a coil spring 2 is provided. The fabric is sewn together by a line of stitches ill (see Figure 1A) behind the coil spring '2 to provide an annular space in which the coil spring 2 may move. The leads 5 of the coil 3a, 3b are passed through the outer fold of the tube 1 through eyelets A sewn to the glass fabric. The space between the two folds of the tube 1 is filled with glass wool insulation s and the free ends of the tube 1 are drawn together by means of the draw cord 9 the ends of the draw cords being pushed inside the thusformed mantle to produce a neat appearance. In the modification shown in Figure 1E, the heating coil l l is spirally wound in the lower part of the heating mantle and consists of three separately wound parts, each having a lead 12 on the negative side, there being a common lead is on the positive side. Apart from this, the other details are the same as the embodiment described with illusillusillusreference to Figures 1A to 1D and are similarly designated.

A second embodiment of the invention is illustrated in Figure 2. The spherical flask has sirgle neck It with a drain-off l5 and is surrounded by a heating mantle iii of knitted glass fabric. The heating coil I"! is spirally wound in the lower half of the mantle l6 and has leads It passing through eyelets I 9 in the outer wall of the mantle l6. Coil springs 2!] and 2| are disposed Within the mantle [8 about the upper and lower openings respectively, so that the springs grip the neck l4 and the drain-01f [5. The inner and outer walls of the mantle l6 are sewn together behind the springs and 2| to form annular spaces in which the springs may move. Glass wool 22 is disposed between the inner and outer walls of the mantle It. The draw cords 23 and 24 are situated on opposite sides of the mantle at the middle point of its length.

In the embodiment of Figure 3, a double neck spherical flask 25 is shown. The heating coil 26 is spirally wound in the lower half of the heating mantle, but, in other respects, the mantle corresponds to that shown in Figures 1A to 1D and similar parts are similarly designated. It will be observed that the coil spring 2 grips the flask around the distant sides of both necks.

An all glass continuous water still flask is shown in Figure l. The spherical flask 27! has a neck 28 and a side entry 28. The heating mantle is somewhat similar to that shown in Fig ures 1A to 1D and similar parts are similarly designated. However, in addition to the coil spring 2 around the neck 28 there is a coil spring 30 around the side entry 29. The method of construction of the heating mantle is also similar to that shown in Figures 1A to 1D. However, the open-ended tube of knitted glass fabric is made with spaced first and second slits along its length which slits lie opposite each other, in the inner and. outer folds, when the tube is folded over to provide a recess for the spring 2. Prior to the folding the spring 30 is placed about the first slit in the inner fold, on the side of the fab ric to which the heating coil is sewn. The edges of the fabric, surrounding the first slit are then curled over the spring and secured to the fabric as at 3|, so as to provide an annular space in which the spring 3% may move. The edges of the second slit in the outer fold. are then secured to their corresponding parts on the first slit as at 40.

Figure 5 illustrates the application of a heating mantle, to a conical flask 32. The heating mantle is of similar construction to that shown in Figures 1A to 1D and is similarly designated. How ever, the disposition and shape of the spiral part 3a and zig--zag part 312 of the heating coil are not the same because of the differently shaped flask. Thus, it will be observed that the spiral part 3a of the heating coil lies along the bottom. of the flask.

In the manufacture of the knitted glass fabric tube, draw cords are either introduced in the knitting or the fabric is seamed at the ends to provide a channel for the draw cords, according to the type of knitting machine used. Thus in Figure 10 the draw cord 28 lies in a channel formed in the fabric 39. Openings for any side entries are provided by leaving out the linking of the selvedges at certain points. However, the side openings can be provided by altering the operation of the needles in the needle bed on a flat bed machine.

In this way it is possible to provide openings at more than one point on the periphery. An alternative method is to provide a number of flat bed pieces and link these together in a suitable manner, leaving holes for ultimate elastic neck openings where required.

The various heating coils may have diflerent parts connected in series or in parallel. Thus a spiral part may be connected in parallel with a zig-zag part of a coil, or a spiral part may contain a number of portions in parallel.

In the use of the heating mantle, the elastic opening (or openings) is (or are) stretched so that it will pass over the flask concerned and the heating mantle is placed around the flask. The neck or other narrow portion of the flask is then gripped by the elastic opening, because of the spring therein, and the heating mantle is in close contact with a large area of the flask.

Knitted fabric is essential to the construction of heating mantles, as the fabric must be flexible and elastic. The heating mantles can be easily applied to chemical apparatus already set up in position. As has been shown, they can be readily applied to flasks which have top openings, bottom openings and side openings, and in effect they grip the flask by their own construction. The capacity for slipping on the mantle from the bottom of the flask is a substantial advantage.

It will of course be understood that insulating material other than glass fabric or glass wool may be employed such as asbestos or quarts.

I claim:

1. An electrical heating device for a vessel hay-- a relatively small discharge neck extend from an enlarged body portion; said heating de vice comprising a unitary flexible mantle do of knitted heat resisting and electrically insu=- lating fibres and formed to define an enclosed space for accommodating the enlarged body por-- tion of the vessel and extending to a relatively small portion of the latter, marginal portions of said mantle defining an opening through which the relatively small portion of the vessel may extend, and electrical heating means carried by said mantle and disposed for good heat exchanging relationship with the body portion of a vessel in the mantle, said opening being normally smaller than the enlarged body portion of the vessel to be received in the mantle whereby the opening may be stretched to pass over the enlarged body portion and can grip the relatively small portion of the vessel.

2. An electrical heating device for a vessel having a relatively small discharge neck extending from an enlarged body portion; said heating device comprising a unitary flexible mantle made of knitted heat resisting and electrically insulating fibres and formed to define an enclosed space for accommodating the enlarged. body pcrtion of the vessel and extending to a relatively small portion of the latter, marginal portions of said mantle defining an opening through which the relatively small portion of the vessel may extend, said flexible mantle including inner and outer walls and flexible insulating material between the latter, elastic means surrounding said opening for yieldably contracting the latter, and an electrical heating coil attached to the surface of said inner wall facing toward said outer wall and disposed for good heat exchanging relationship with the body portion of a vessel in. the mantle, said opening being normally smaller than the enlarged body portion of the vessel to be received in the mantle whereby the opening may be stretched to pass over the enlarged body portion and can grip the relatively small portion of the vessel.

3. An electrical heating device according to claim 2; wherein said heating coil includes a spirally wound part in the portion of said mantle diametrically opposed to said opening and a part Wound in zig-zag form and extending around the portion of the mantle between said opening and said portion diametrically opposed to the opening so that the last mentioned part of said heating coil can expand and contract with the mantle to accommodate vessels of different configurations in the mantle.

4. An electrical heating device according to portions of the mantle defining said opening.

HEINZ HERBERT GOLDSTAUB.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 978,892 Janssen Dec. 20, 1910 1,455,287 Hadley May 15, 1923 2,231,506 Morey Feb. 11, 1941 2,482,665 Geyer Sept. 20, 1949 2,500,241 Brown Mar. 14, 1950 2,5218% Weidenschilling Oct. 31, 1950 2,572,695 Briscoe et a1 Oct. 23, 1951

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