US2729733A - Heating device - Google Patents

Description

Jan. 3, 1956 A- G. HERON HEATING DEVICE Filed June 24, 1952 2 Sheets-Sheet 1 A- G- HERON HEATING DEVICE Jan. 3, 1956 2 Sheets-Sheet 2 Filed June 24, 1952 Invent r b r/rm ornqs United States PatentO HEATING DEVICE Andrew George Heron, Newcastle upon Tyne, England, assignor to Heron Heating Devices Limited Application June 24, 1952, Serial No. 295,267 6 Claims. (Cl. 219-19) This invention consists in an improved heating device or mufiler for melting or loosening from their containers, thermoplastic materials which are solid at normal temperatures, such as solidified liquids or semi-liquids, and for drying containers.

Heavy oils such as paraffin wax, petroleum jelly and grease are usually transported in steel drums, and hitherto it has been a problem to have the drums emptied or the contents melted in a clean fashion and in a short time. Steam has been used for this purpose, but the necessary plant required and the time taken makes the process ex pensive; while heating by the usual electric elements is dangerous owing to the inflammable nature of the material being heated; and infra red lamps have a relatively short life and have a high breakage risk.

The object of the invention is to provide a device which will give the maximum amount of heat at a relatively low temperature, and, in one application of the device, heat the outside of the material at an evenly distributed temperature without any cold spots, the latter leaving areas of undissolved solid which prevent the clean discharge of the mass of material from the container; or liquify the whole or part of the contents; and in another application dry a container in a relatively short time.

The muflier according to the invention is adapted to pass over the container to be treated, and comprises a wall, an electric heating cable on said wall said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, so that a current may be passed through the conductor to heat it without its being oxidised, and means for connect ing the conductor to an electric supply source.

The invention will now be described by way of example with reference to the accompanying drawings.

In the said drawings:

Fig. l is a vertical section of a heater device for treating single drums of petroleum jelly or grease or other heavy oil.

Fig. 2 is a plan of Fig. 1.

Figs. 3 to 5 are diagrammatic views showing the heater device in use for different purposes.

Fig. 6 is a vertical section of an alternative form of coil former for use when a number of small drums are to be treated by the same muflle.

' Referring more particularly to the drawings, the device comprises a hollow coil former A consisting in a number of equally spaced Tbars 1 secured to top and bottom rings 2, 3, with their Webs pointed inwards, the upper ends of the said T-bars being covered by a shallow cover 40f heavy Wire mesh which is Welded to the ring 2, while a cruciform frame 6 having its four outer ends bent downwards at right angles is secured by the latter to the ring 2. A threaded bolt 7 is secured to the intersecting portion of the frame 6 to receive a lifting ring hereinafter referred to. The lower ends of the T-bars are curved outwards and have lugs 11: formed at their ends for securing to an outer barrel 13 hereinafter described.

About the coil former there is helically wound a length of heating cable 9 in the form of a conductor which may be steel, aluminium, copper or copper alloy, for example that marketed under theregistered trademark Kumanal, encased in an insulator such as magnesium oxide or silicate which itself is encased in a copper or other metallic sheath. The ends of the coil or coils 9 are connected to a terminal box 11 hereinafter referred to. There may be one or more coils, the spacing being conveniently eifected by first placing against the T-bars 1 crimped wires 10 the crimpings in which are spaced according to the de sired spacing, and preferably so that as the coils approach the upper end of the former the pitch increases. If desired, the last coil adjacent the mesh cover 4 may be led over the latter to form a spiral thereon, and then connected to the terminal box 11.

The length and thickness or cross sectional area and resistance of the conductor are selected so that when the current is switched on the required amount of low tem perature heat is generated.

An inner barrel 8 in the form of a cylinder which is closed at its upper end and having a flange 8a at its lower end is passed over the coil former A with its completed coils 9. The upper end of the barrel 8 is drilled centrally to allow the passage of the bolt. Equally spaced on a. circumferential marginal line are four threaded bolts 12 which are welded to the upper side of the upper end of the barrel.

An outer barrel 13 which is open at its upper end to which a cruciform frame 14 is welded, is then passed over the inner barrel 8, whose flange 8a is welded to its lower end, while the lugs 1a of the T-bars are bolted to the lower end of the barrel 13 which is strengthened by a rim 13a on the outside of the barrel. The horizontal portions of the frame 14 are drilled to allow the passage of the bolts 12 on the inner barrel 8, nuts 15 being provided for the correct spacing of the barrel 13 from the barrel 8, and nuts 16 serving to secure the upper ends of the two barrels together.

An opening is formed near the upper end of the barrel l3, and over this opening is secured the terminal box 11 above referred to, to which the lead in wires for the cable 9 are connected. Also a thermostat 18 for setting the mufller at any desired temperature is mounted on the terminal box 11 so as to project through the opening and fitted to the inner surface of the inner barrel 8 so that it lies between the latter and the coiled cable 9.

Thermal insulation material such as slag wool or fibre glass is packed in the space between the barrels 8 and 13, after which a removal cover 19 having openings therein corresponding to the lifting ring bolt 7 and a vent 20 from the inner barrel 8 is placed over the barrel 13, being held in position by a nut 21 on the bolt 7. A lifting ring 22 is then passed over the bolt 7 and secured by a nut 23.

Lifting handles 24 are welded to the lower portion of the outer barrel 13 for assisting in the guiding of the device over the barrel to be treated.

In use, the mufiler M is suspended by its lifting ring 21 to a counterbalanced hoisting cable, and raised. An open drum D containing petroleum jelly is then placed over an opening in a platform above a mixing tank with its open end lowermost. The muffier M is then lowered over the container as shown semi-diagrammatically in Fig. 3. The current is switched on; and as a result of the evenly distributed coils of the heating cable 9 a large volume of evenly distributed low temperature heat flows through the wall of the drum so that the outer skin of the petroleum is rapidly melted, flows down and so allows air to pass between the petroleum and the wall of the drum, and thus destroys any vacuum effect; and thereafter gravity causes the relatively unheated contents to drop into the mixing tank. 7

When it is desired to melt or reduce the viscosity of the contents of a barrel the. heating is continued until the desired effect is obtained.

in such heating the barrel is placed in its normal position.

The device lends itself very conveniently to the drying of drums containing residual moisture.

This may be done in more than one way. Referring to Fig. 4, the mufiier M is about 6 inches higher than that shown in Fig. 3. This is to allow of the drum D being stood on a trivet 25 so that heat from the lowermost portion of the coils l flows upwards to the lower end of the drum. in an opening in the side of the muffler there is adapted to be inserted a flexible pipe 26 whose other end is connected to the inlet or outlet orifice of a circulating pump 27, and to one of the usual openings in the drum D which is locatedunder the vent 20, a

second flexible pipe 28 is connected, the other end of which is adapted to be connected to the other orifice of the circulating pump 27. The current is switched on, and the pump put into operation. The relatively large volume of low temperature heat rapidly vapourises any moisture on the walls of the drum and the heated air is circulated by the pump, so that the drum is efficiently heated by a current of hot air in a closed circuit. Any moisture in the drum is thus rapidly vapourised and soon discharges as steam from the upper opening in the drum and through the vent 2%.

When a standard size muffler is used, the drum D is stood upon a hot plate 29, as shown in Fig. 5, which may comprise heating coils similar to those around the coil former A above described. This ensures the drum D being heated from the bottom. However, the objection to this method is the necessity of providing an addi tional heater.-

Fig. 6 shows a modified form of coil former adapted for use when drums of smaller diameter are to be treated; for as will be appreciated, in the form shown in Figs. 1 and 2 the coils of the cable 9 are polygonal, so that while the webs of the T-bars 1 are sufficient for maintaining the coils spaced from the wall of the drum for which the device is particularly designed, they will not be for drums of considerably smaller diameters. In the form shown in Fig. 6, the former is made of a relatively rigid square mesh of about 1 inch in the shape of an inverted bell 3h, so that the coils are virtually supported throughout by the mesh, and so cannot come into contact with the drums. The bell 3% is flanged outwards at its lower end and is supported on a cruciform frame 31 having the lower ends of its members bent outwards and. upwards as at Ella, the latter being bolted to the low rim of the barrel 13. This frame 31 corresponds to the frame 6 of Figs. 1 and 2.

The invention is applicable to the discharge of all solidified liquids or semi-liquids, for example honey, butter, lard Where all that is necessary to drop the contents from the drum is that the outer skin be softened.

1 claim:

1. A mufiler for melting or loosening thermoplastic materials such as solidified liquids or semi-liquids from their containers and for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable wound on said former in the form of a helix, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, an inner metal barrel covering said former, an outer metal barrel enclosing the inner barrel and rigidly spaced therefrom, thermal insulation material in the space between said barrels, and a-terrninal-box on the outer barrel to which the ends of the heating cable are com ill nected, and which is adapted to be connected to an electric supply source.

2. A muffler for melting or loosening thermoplastic materials such as solidified liquids or semi-liquids from their containers and for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable wound on said former in the form of a helix, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, an inner metal barrel covering said former, an outer metal barrel enclosing the inner barrel and rigidly spaced therefrom, thermal insulation material in the space between said barrels, and a terminal box on the outer barrel to which the ends of the heating cable are connected, and which is adapted to be connected to an electric supply source, a horizontal frame on the upper end of said former, a vertical central bolt rigidly mounted on said frame, said bolt passing through the inner and outer barrels, and a lifting ring on the outer end of said bolt.

3. A muflier for melting or loosening thermoplastic materials such as solidified liquids or semi-liquids from their containers md for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable Wound on said former in the form or" a helix, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, an inner metal barrel covering said former, an

outer open ended metal barrel enclosing the inner barrel and rigidly spaced therefrom, thermal insulation material in the space between said barrels, and a'terminal box on the outer barrel to which the ends of the heating cable are connected, and which is adapted to be connected to an electric supply source, a horizontal frame on the upper end of said former, a vertical central bolt rigidly mounted on said frame, said bolt passing through the inner and outer barrels, and a lifting ring on the outer end of said bolt, a frame extending across the upper end of said outer barrel, through the members of which the central bolt passes, and a removable cover with openings to accommodate said central bolt, said cover closing the upper end of the muffler.

4. A muffler for melting or loosening thermoplastic material such as solidified liquids or semi-liquids from their containers and for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable wound on said former in the form of a helix, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium cncasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, an inner metal barrel covering said former, an outer metal barrel enclosing the inner barrel and rigidly spaced therefrom, thermal insulation material in the space between said barrels, and a terminal box on the outer barrel to which the ends of the heating cable are connected, and which is adapted to be connected to an electric supply source, a horizontal frame on the upper end of said former, a vertical central bolt rigidly mounted on said frame, said bolt passing through the inner and outer barrels, and a lifting ring on the outer end of said bolt, said former comprising a number of spaced vertical T- bars secured to rings with their webs pointing inwards, and their lower ends curved outwards for securing to the lower end of said outer barrel.

5. A mufder for melting or loosening thermoplastic materials such as solidified liquids or semi-liquids from their containers and for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable Wound on said former in the form of a helix, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a continuous metallic sheath encasing said insulation medium throughout its length, an inner metal barrel covering said former, an outer metal barrel enclosing the inner barrel and rigidly spaced therefrom, thermal insulation material in the space between said barrels, and a terminal box on the outer barrel to which the ends of the heating cable are connected, and which is adapted to be connected to an electric supply source, a horizontal frame on the upper end of said former, a vertical central bolt rigidly mounted on said frame, said bolt passing through the inner and outer barrels, and a lifting ring on the outer end of said bolt, said coil former comprising an inverted bell of relatively rigid square mesh, and having its lower end flanged outwards, a frame supporting said bell, said frame having the lower ends of its members bent outwards for securing to the lower end of said outer barrel.

6. A muffler for melting or loosening thermoplastic materials such as solidified liquids or semi-liquids from their containers and for drying containers, adapted to pass over the container to be treated, and comprising a hollow bell-like coil supporting former, an electric heating cable wound on said former in the form of a helix, cn'mped bars on said former for ensuring the desired spacing of the cable coils, said heating cable comprising a rectilinear conductor, a continuous refractory insulation medium encasing said conductor throughout its length, and a conouter barrels, and a lifting ring on the outer end of said bolt.

References Cited in the file of this patent UNITED STATES PATENTS 312,002 Miller Feb. 10, 1885 1,310,060 Collins July 5, 1919 1,427,319 Peacock Aug. 29, 1922 1,960,697 Cochran et al. May 29, 1934 2,073,190 Bartlett et al Mar. 9, 1937 2,169,404 Buttner Aug. 15, 1939 2,208,087 Somers July 16, 1940 2,351,482 Campbell June 13, 1944 2,472,144 Calhoun June 7, 1949 2,590,899 Snelling Apr. 1, 1952 2,623,149 Amar Dec. 23, 1952 2,632,836 Ackley Mar. 24, 1953 OTHER REFERENCES Electric Heaters and Heating Devices, General Electric 00.; Schenectady, New York; December 1941 (GED- 650B) (page 4).

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