US3784783A

US3784783A - De-icing structure for roofs

Info

Publication number: US3784783A
Application number: US00344646A
Authority: US
Inventors: G Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-26
Filing date: 1973-03-26
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A device and method for melting ice and snow on a roof structure; the device comprises upper and lower portions with heating means, for example, a heating cable supported on said lower portion; the device is supported on a sloping portion of a roof and the melted and melting ice and snow flows downwardly under gravity.

Description

United States Patent Gray 1 1 Jan. 8, 1974 1 1 DE-ICING STRUCTURE FOR ROOFS 3,617,691 11/1971 Toyooka et a1 219 201 3,725,638 4/1973 Solin et a1.... 219/213 [76] Inventor: Guy Gordon 'F 1654 Pme 2,699,484 1/1955 Michaels 219 213 Terrebonne Helghtsi Quebec, 3,521,029 7/1970 Toyooka et a1 219/213 x Canada [22] Filed: Mar. 26, 1973 Primary Examiner-C. L. Albritton PP (571 XBSTRKC 'I A device and method for melting ice and snow on a [52] U.S. Cl. 219/213, 165/47 roof structure; the device comprises upper and lower [51] Int. Cl. H05b 1/00 portions with heating means, for example, a heating [58] Field of Search 219/213, 20]; cable supported on said lower portion; the device is 165/47 supported on a sloping portion of a roof and the melted and melting ice and snow flows downwardly [56] References Cited under gravity.

UNITED STATES PATENTS I 8 Claims, 4 Drawing Figures 2,507,039 5/1950 Miller 219/213 3 32. 3/ 22 .1341 H W F DE-ICING STRUCTURE FOR ROOFS BACKGROUND OF THE INVENTION a. Field of the Invention This invention relates to a device and method for the removal of ice and snow from a roof structure and more especially, from the sloping portion of a roof structure.

b. Description of the Prior Art In areas which suffer from heavy snow falls, the roofs of buildings are often subjected to heavy loads due to the accumulation of ice and snow. This is damaging to the roof and in some cases, the roof of a building has been known to collapse under the weight of accumulated ice and snow. In addition, the accumulation of ice and snow on a roof, particularly at the edge of the roof is hazardous to people on the ground below, since the accumulated ice and snow may periodically fall in large amounts from the roof.

In other cases, and particularly with roof structures comprising shingles, which may for example be made of wood, the ice and snow may rot the shingles, thereby causing permanent damage to the roof and even collapse of the roof.

Attempts have been made to overcome this problem by the use of a continuous length of heating cable trained around the edge of the roof structure. However, this structure has been costly because of the length of heating cable required, and has not been very satisfactory in use and users have still had damage caused to the roofs of their buildings from the accumulation of ice and snow.

SUMMARY OF THE INVENTION According to the invention a device for melting ice and snow on a roof structure comprises upper and lower portions, said upper portion being spaced apart from and supported on said lower portion, heating means between said upper and lower portions and means for supporting the device on a sloping portion of a roof structure.

According to a feature of the invention, the device is associated with the edge portion of a sloping roof.

According to a further feature of the invention, the device is associated with a roof sloping inwardly from its edges to draining means.

According to another aspect, a method of melting ice and snow on a roof structure comprises mounting on a sloping portion of the roof structure a device comprising a housing having heating means therein, said housing covering a small part only of said roof structure, applying said heating means to heat said ice and snow and allowing melted or melting ice and snow to flow downwardly under gravity to draining means.

The device and method according to the invention have shown satisfactory experimental results in use. A roof on which the device was tested suffered no damage, ice and snow being melted by the device before it could accumulate in large amounts on the roof.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention is illustrated with reference to the drawings, in which:

FIG. 1 illustrates a preferred form of device according to the invention,

FIG. 2 illustrates a preferred arrangement according to the invention for locating the device with respect to the shingles on the roof structure,

FIG. 3 illustrates an elevation of a different embodiment of the device according to the invention, and

FIG. 4 illustrates a plan of the embodiment of FIG. 3 with the top removed.

DESCRIPTION OF PREFERRED EMBODIMENTS With reference to FIG. 1 a roof A has a de-icing device B mounted on it, the device B has a bottom panel 2 and a top panel 3 spaced apart from and supported on the bottom panel 2 by side walls 5 and 8 to provide a narrow passageway 4 therebetween.

A heating cable 11 preferably comprising an electrically resistive heating element encased in a lead tubing is trained along bottom panel 2; the ends of the heating cable 11 being connected to a terminal 13 supported on side wall 5.

Side walls 5 and 8 comprise wall portions 50 and 8c respectively, the lengths of which are less than the width of bottom and

top panels

2 and 3 respectively, and

flanges

5a, 5b and 8a, 8b respectively. Flanges 5a and 8a are secured to top panel 3 preferably by means of screws so that the top panel 3 can be easily removed for access to the heating cable 11. Flanges 5b and 8b are secured to the bottom panel 2, for example, by riveting.

Located between bottom panel 2 and top panel 3 are support members 6 and 7, which are similar to side walls 5 and 8 and include flanges 6b and 7b respectively, which are secured, for example by riveting, to bottom panel 2, and flanges 6a and 7a respectively, which are secured preferably by means of screws to top panel 3.

' Support members 6 and 7 provide additional support for top panel 3, which may be subjected to heavy loads of snow and ice, if the device B is not in operation for some reason.

The bottom panel 2 is bent at its outer edge to form a hook 9 at the edge which contacts the edge of the roof A, when the device B is located on the roof A. The hook 9 defines a recess 10, the use of which is described below.

The heating cable 11 is trained from terminal 13 along the length of the bottom panel 2 adjacent the lengthwise edge of the bottom panel 2 remote from hook 9 to form a first straight portion 11a, and is bent to form a series of loops 11b across the bottom panel 2 commencing adjacent side wall 8, the loops are arranged so as to span the surface of the bottom panel 2 in a substantially uniform pattern terminating adjacent side wall 5; the heating cable 11 is further trained along the length-wise edge of the bottom panel 2 adjacent the hook 9 to form a second straight portion 1 1c terminating at side wall 8 and is returned to the terminal 13 along the underside of the bottom panel 2, where it is located in the recess 10 defined in the hook 9.

The heating cable 11 is fastened to the bottom panel 2 by means of clips 12 at spaced points along its length.

' Suitably, the clips 12 are located at the turning points 3 hook 9 to locate the edge C of the roof A to which they are secured, for example, by screws.

In use the de-icing device B is secured to the edge C of the roof A by means of the brackets l4, 15, 16 and 17.

With reference to FIG. 2, the inner edge l8'of the bottom panel 2 of device B is located so that it lies in the recess 19 between the

shingles

20 and 21 of a roof A.

Structural component parts of the device B are suitably made of aluminum. However, other materials may be used, for example, iron, but materials used for the top panel 3 should have sufficient strength to withstand loads of ice and snow, which might accumulate on it, when the device B is switched off. Naturally, the component parts should be capable of withstanding the heatemitted by the heating cable ll.

In an example of a de-icer according to the invention and ofthe form illustrated with reference to FIG. 1, the panels and brackets were made from aluminum sheeting 0.4 inches in thickness, the overall length of the deicer was about 8 feet, the width was about I 1.75 inches and the passageway between the top and bottom panels was about 1.0 inch in height. The side walls 5 and 8 and the support members 6 and 7 were 10 inches long and 1 inch high, the flanges for example 5a all being 0.5 inches in width. The support members 6 and 7 were spaced at a distance of 2 feet from side walls 5 and 8 respectively. The brackets l4, l5, l6 and 17 for securing the bottom panel to the roof were about 3 inches long and 0.75 inches wide. The heating cable 11 was a lead sheathed heating cable of the HC Heating Cable type supplied by Canadian General Electric with an overall length of about 60 feet and'a diameter of about 0.25 inches. The working voltage of the heating cable 11 is about 115 volts and its power output is about 420 watts. The cable 11 terminated in a moisture-proof NEMA U-Ground Plug terminal 13, and the lead sheath of the heating cable was connected to the ground terminal.

With reference to FIGS. 3 and 4, a roof D of the type which slopesinwardly from its edges to a drain E has mounted on it a de-icing device F. The device F has a bottom panel 22, and a top panel 23 spaced apart from and supported on bottom panel 22 by

support members

25, 26 and 27 to provide a narrow passageway 24 between top panel 23 and bottom panel 22..

A heating cable 31 is entrained around bottom panel 22, the ends of the heating cable 31 being connected to a terminal 33 in support member 25.

An opening 28 is defined about the centre of bottom panel 22 from which a tubular spigot 29 extends; the spigot 29 being located in the drain E.

The

support members

25, 26 and 27 are located generally radially on bottom panel 22 and have flanges a, 26a and 27a respectively which are secured, for example, by means of screws, to top panel 23, and flanges 25b, 26b and 27b secured, for example, by riveting to bottom panel 22.

The heating cable 31 is trained from terminal 33 to form a generally circumferential portion 31a on the bottom panel 22 to a point adjacent support member 25, and is bent to form a series of loops 31b commencing adjacent one side of support member 25, and terminating in terminal 33.

The heating cable 31 is fastened to the bottom panel 22 by means of clips 32 at spaced points along its length. Suitably the clips 32 are located at the turning points of the series of loops 31b, and at intervals along the circumferential portion 31a.

The bottom panel 22 is shown as being generally horizontal and this provides satisfactory results where the slope of the roof has a sufficient gradient to give the melted and melting ice and snow a sufficient velocity to flow to opening 28. In other cases, however, it may be necessary to utilize a bottom panel, which tapers inwardly so as to be ofa generally inverted frusto-conical form.

In operation the de-icing device B in FIGS. 1 and 2 is located on a sloping portion of roof A as described, and the terminal 13 of the heating cable 11 is connected to a source of electricity, the heating cable 11 is heated by the passage of electrical current and the heat emitted melts ice and snow on and around the device B; the melted ice and snow flows downwardly under gravity along the slope thereby preventing the accumulation of ice and snow on the edge of the roof. Ice and snow on the roof in the adjacent areas then migrates over the areas from'which ice and snow have been removed towards the device B, where they are melted. The device B can be painted to match the col our of the roof and a dull, non-polished, painted surface enhances the heat radiation, thereby increasing the effective heating area of the de-icer.

The narrow passageway 4 is effective to provide currents of warm air, so that the ice and snow is heated both by convection currents of warm air, and by heat radiation from the heating cable 11 and the structural components of the device B.

The passageway 4 also allows the melted or melting ice and snow directly behind the device 8' to flow through the device B. In the absence of passageway 4, the device B would of course provide an obstruction to the material flowing behind it.

It is also within the scope of the invention to have a second heating cable secured to the underside of the top panel 3 of the device B. V

In practice, it is found that a single de-icing device B of the dimensions described above is satisfactory for use on one side ofa roof 30 ft. long and 15 ft. wide. For larger roofs two or more de-icers may be connected in series along the edge of the roof.

In the case of a roof having aninverted V-crosssection, a device B is preferably located at the bottom edge of each arm of the inverted V. a

The de-icing device F operates in a similar manner to device B except that in this case, melted and melting ice and snow flows into passageway 24 through the opening 28 to the spigot 29 and into the drain B. When the bottom panel 22 is of an inverted frusto-conical form, this facilitated flow of the melted and melting ice and snow of the opening 28.

I claim:

1. A device for melting ice and snow on a roof structure comprising upper and lower portions, said upper portion being spaced apart from and supported on said lower portion, heating means between said upper and lower portions and means for supporting the device on a sloping portion of a roof structure, wherein said bottom portion has an opening defined in a central part thereof and said means comprises a tubular downwardly extending spigot adapted to fit in a drain means.

2. A device for melting ice and snow on a roof structure comprising upper and lower portions, said upper portion being spaced apart from and supported on said lower portion, heating means between said upper and lower portions and means for supporting the device on a sloping portion of a roof structure, said upper and lower portions being spaced apart by side wall members to define a narrow passage between the upper and lower portions for melted and melting ice and snow and air convection currents to pass through.

3. A device according to claim 2 wherein said heating means comprises an electrical heating cable mounted on said lower portion. 7

4. A-device according to claim 3 wherein said cable is trained for part of its length in a series of loops.

and snow according to claim 2.

Claims

3. A device according to claim 2 wherein said heating means comprises an electrical heating cable mounted on said lower portion.

4. A device according to claim 3 wherein said cable is trained for part of its length in a series of loops.

5. A device according to claim 3 wherein the bottom portion is curved over along one edge to form a hook defining a recess, said heating cable being contained in said recess along a part of its length.

6. A device according to claim 2 including spaced apart support members intermediate said side walls to provide additional support for said top portion.

7. A device according to claim 2 wherein said lower and upper portions are of aluminum sheeting.

8. In combination with a roof a device for melting ice and snow according to claim 2.