JP4857001B2 - Snow melting equipment - Google Patents

Description

  The present invention relates to a snow melting device using a linear heating element installed on a roof or the like as a heat source.

  Conventionally, in order to melt snow on a building roof or the like, a snow melting device in which a heating element is arranged on a roof or the like as a support base and a heat sink such as aluminum is mounted on the heating element has been used. Yes. In such a snow melting device, the heat generating element generates heat during snowfall, and the heat generated from the heat generating element is transmitted to the heat radiating plate, so that it is possible to melt the snow as it is without being accumulated on the roof.

  For example, as an example of such a snow melting device, a flexible wire heating element is arranged on the roof surface so as to have a meandering shape composed of a plurality of straight portions and curved portions, and a heat transfer cover (heat sink) is placed on the straight portions. ) Has been proposed (see Patent Document 1). Such a snow melting device can effectively heat a wide area of the roof and melt snow.

  In the snow melting device with the wire heating element arranged in this way, it is necessary that the wire heating element and the heat transfer cover (heat radiating plate) are in sufficient contact. If the contact becomes unstable, the wire heating element generates heat. Heat cannot be efficiently transmitted to the heat sink, resulting in a decrease in snow melting efficiency. In order to ensure the contact state, it is an effective means to provide an urging means for urging the heating element toward the heat radiating plate, and an example thereof is described in, for example, Patent Document 2.

  Specifically, as shown in FIG. 4, in the snow melting device 70, between the support base B and the heat radiating plate 74, a line heating element 71 and a biasing means 72 that biases the line heating element 71 upward, And a receiving body 73 that accommodates the wire heating element 71 and the urging means 72 is arranged on the support base B so that the line heating element 71 can slide in the vertical direction. With this configuration, the wire heating element 71 is effectively brought into contact with the lower surface of the heat radiating plate 74 by the upward biasing force from the biasing means 72, and high thermal conductivity is ensured.

JP-A-2005-273406 JP 2000-170334 A

  By the way, such a snow melting device may be stepped on by a builder from above during installation on the roof, and a large downward load acts on the heat sink. Also, if there is a large amount of snow when the snow melting device is not operating, a large downward load acts on the heat sink as well. In such a case, in the snow melting apparatus of the form shown in FIG. 4, as the downward load increases, the urging means cannot sufficiently absorb the load acting on the wire heating element. The heating element can be damaged or the contact between the wire heating element and the heat sink can be lost.

  On the other hand, when the snow melting device is operated, the heat radiating plate is thermally expanded by the heat of the heating element and tends to warp upward. However, in the snow melting apparatus having the configuration shown in FIG. 4, when the amount of warping of the heat sink increases, the upward biasing force of the biasing means against the wire heating element gradually decreases, and the adhesion between the wire heating element and the heat sink is increased. May be exacerbated.

  The present invention has been made in view of the above-described problems, and prevents damage to the wire heating element even when a large load acts on the wire heating element from the heat dissipation plate side in the snow melting device. The first purpose. A second object is to always ensure the adhesion between the wire heating element and the heat sink even when the heat sink is warped upward.

  A snow melting device according to the present invention is a snow melting device having a configuration in which a wire heating element and a biasing means for biasing the wire heating element upward are arranged between a support base and a heat radiating plate. An upper frame that covers the straight portion of the body from above, the upper frame having a top plate located between the heat radiating plate and the wire heating element, and left and right side walls, and an urging means By urging the wire heating element upward by the above, it is possible to maintain a posture in which the wire heating element abuts on the lower surface of the top plate of the upper frame and the upper surface of the top plate contacts the lower surface of the heat radiating plate. The downward movement amount of the plate is regulated by the lower ends of the left and right side walls of the upper frame body being in contact with the support base.

  In the snow melting device according to the present invention, the urging means urges the wire heating element upward so that the posture in which the wire heating element abuts on the bottom surface of the top frame and the top surface of the top plate abuts on the heat sink surface can be maintained. Therefore, the heat generated by the wire heating element can be efficiently transmitted to the heat dissipation plate via the top plate of the upper frame. In addition, even when the heat sink is heated upward, the wire heating element can follow the movement of the lower surface of the heat sink by the biasing force of the biasing means, thus maintaining high thermal conductivity. can do.

  Furthermore, the lower ends of the left and right side walls of the upper frame can abut against the support base to regulate the amount of downward movement of the heat sink, so that, for example, when the operator steps on the construction or when the device is not in operation Even if a large downward load acts on the heat radiating plate due to a large amount of snow, it is possible to effectively avoid damaging the wire heating element.

  In the present invention, the wire heating element is preferably flexible enough to be arranged in a meandering shape composed of a straight portion and a curved portion, and can be wound when removed from the roof top surface after being used as a snow melting device. It is more preferable if it is soft. The linear heating element may be an arbitrary linear heating element, but a plurality of PTC elements (Positive Temperature Coefficient) serving as heat sources are arranged along the longitudinal direction of the linear heating element, and are disposed at both ends of these PTC elements. It is preferable to have a structure in which conductors for connecting the PTC elements are arranged. Furthermore, the PTC element and the conductor are preferably covered with an insulator made of a synthetic resin having flexibility. As such a PTC element, a resistor having excellent thermal conductivity, that is, a ceramic resistor using barium titanate or a polymer composition containing a particulate conductive agent such as carbon black. Polymers and the like can be used.

  In the present invention, the heat radiating plate and the upper frame body are not particularly limited as long as they can transmit heat from the wire heating element, but aluminum (A6062) is considered in consideration of high heat conductivity, product cost, and the like. ), Stainless steel and iron are preferred. In order to improve the design and durability, these members may be subjected to a surface treatment such as painting or plating.

  In the present invention, the urging means for urging the wire heating element upward may be a foam of a synthetic resin such as polyethylene, polypropylene, silicon rubber, etc. on the condition that the required cold resistance is provided. A leaf spring body utilizing the elastic deformation of the metal may be used. In the latter case, an urging force that is more stable in the long term can be applied to the wire heating element.

  In a preferred aspect of the snow melting device according to the present invention, the snow melting apparatus further includes a bottom frame having a bottom plate located between the support base and the biasing means and left and right side walls, and left and right side walls and a lower frame of the upper frame body. Locking means for limiting the upward movement amount of the upper frame is formed between the left and right side walls of the body.

  In this way, by providing the locking means and limiting the upward movement amount of the upper frame body, even when an upward warp occurs in the heat sink, up to the upper limit restriction position of the movement of the upper frame body, By the upward biasing force by the biasing means, it is possible to reliably maintain a high close contact state between the wire heating element and the upper frame body and a high close contact state between the upper frame body and the heat radiating plate.

  The structure of the lower frame is not particularly limited on the condition that it includes means for limiting the amount of upward movement of the upper frame, but the attachment of the lower frame to the support base and the manufacturing cost are not limited. In view of the above, a U-shaped cross section structure having a bottom plate and left and right side walls is preferable. Moreover, it is also preferable that at least the bottom plate of the lower frame is provided with a heat insulating material such as foamed resin. As a result, heat transfer to the support base can be reliably prevented, and as a result, the heat generated by the wire heating element can be efficiently transmitted to the upper frame.

  In the snow melting device according to the present invention, the vertical compression amount of the urging means when the lower ends of the left and right side walls of the upper frame abut against the support base is the thermal expansion caused by the heat generated by the linear heating element. It is preferable that the amount of upward movement of the upper frame body by the locking means is limited so as to be larger than the maximum upward warping amount of the heat sink. By adopting this aspect, even when the upward warping amount of the heat sink is maximized, a predetermined upward biasing force (for example, the lower surface of the heat sink deformed by warping) is imitated by the biasing means. Thus, it is possible to reliably ensure a biasing force capable of contacting the upper surface of the top plate of the upper frame body, and it is possible to reliably avoid a decrease in the heat conduction efficiency of the snow melting device.

  In the present invention, the upward warping of the heat sink means, for example, when the snow melting device is operated with the periphery of the heat sink fixed to the support base, due to the heat generated by the wire heating element. This refers to a phenomenon in which a heat sink with a linear expansion coefficient higher than that of the support base warps upward due to a difference in thermal expansion depending on the temperature difference with the plate. It can be calculated using the fixed position, the size of the heat sink, the thermal expansion coefficient of the material of the heat sink, the heat generation temperature of the wire heating element, and the like.

  In the snow melting device according to the present invention, it is preferable that a coating film is formed between the upper surface of the top frame and the lower surface of the heat sink. As a result, even if there is a slight unevenness (non-land) on the top surface of the top frame and the bottom surface of the heat sink, the adhesion between them can be improved, and the heat between the top frame and the heat sink can be improved. The conduction efficiency can be further increased. Moreover, it is more preferable that it is a coating film with adhesiveness, and thereby the followability of the upper frame body with respect to the heat radiating plate can be improved even when the heat radiating plate is warped upward as described above. . Examples of such a coating film include silicone for heat dissipation, a silicone rubber sheet, and grease.

  ADVANTAGE OF THE INVENTION According to this invention, in a snow melting apparatus, it can prevent reliably that a linear heating element is damaged with the load from above. Further, even when the heat sink is warped upward, the heat transfer efficiency from the wire heating element to the heat sink can be favorably maintained. Therefore, high snow melting efficiency can be obtained.

  Hereinafter, an embodiment of a snow melting device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a main part schematically showing an example of a snow melting device (a plan view seen from above when a heat radiating plate described later is removed), and FIG. A cross-sectional arrow view is shown.

  As shown in FIGS. 1 and 2, the snow melting device 1 according to this embodiment includes a wire heating element 11 between a support base B that is a roof of a building and a heat radiating plate 30 made of, for example, aluminum. A biasing means 12 for biasing the wire heating element 11 upward is provided. The line heating element 11 is a flexible line heating element and has an oval cross-sectional shape. Specifically, the wire heating element 11 includes a plurality of PTC elements (not shown) serving as heat sources arranged along the line direction, and conductors (for connecting the PTC elements connected to both ends of these PTC elements). (Not shown), and the PTC element and the conductor are covered with a flexible synthetic resin insulator. As shown in FIG. 1, such a flexible wire heating element 11 is arranged on the roof (support base B) so as to have a meandering shape in which the straight portion 11a and the curved portion 11b are combined. Yes.

  As shown in the figure, each linear portion 11a of the wire heating element 11 is covered with an upper frame 20 from above. The upper frame 20 has a top plate 21 positioned between the heat radiating plate 30 and the wire heating element 11 and left and right side walls 22, 22, and the wire heating element 11 is moved upward by the urging means 12. The linear heating element 11 can be in close contact with the top plate lower surface 21b of the upper frame 20, and the top plate upper surface 21a can be maintained in close contact with the heat sink lower surface 30a. It is like that. On the other hand, the downward movement amount of the heat radiating plate 30 is regulated by the lower ends 22 a of the left and right side walls 22 of the upper frame body 20 coming into contact with the support base B. In the illustrated example, when the heat sink 30 is placed on the upper frame 20, the upper frame 20 receives the load of the heat sink 30, and the lower ends 22 a and 22 a of the left and right side walls 22 are attached to the support base B. It is in a contact state.

  Thus, since the urging means 12 urges the wire heating element 11 upward, the heat generated by the wire heating element 11 is efficiently transmitted to the heat radiating plate 30 via the top plate 21 of the upper frame body 20. . Further, as shown in FIG. 3, even when the heat radiating plate 30 is warped upward due to the heat generated by the wire heat generating body 11, the wire heat generating body 11 is moved upward by the urging means 12 by the urging means 12. It can follow to match.

  Further, since the lower ends 22a of the left and right side walls 22 of the upper frame 20 abut against the support base B so as to regulate the downward movement amount of the heat radiating plate 30, the downward load from the heat radiating plate 30 is applied to the left and right side walls. It can be supported by the lower end 22a of the 22. Therefore, even if a downward load acts on the heat sink 30 due to the operator's stepping on the construction and snow accumulation when the apparatus is not in operation, the top plate 21 of the upper frame 20 and the left and right side walls 22 and 22 are surrounded. Since the wire heating element 11 is accommodated in the space, damage to the wire heating element 11 can be avoided.

  Further, in the illustrated example, the snow melting device 1 has a bottom frame 41 having a bottom plate 41 and left and right side walls 42, 42 positioned between the support base B and the urging means 12. Forty bottom plates are fixed to the support base B. Further, between the left and right side walls 22 of the upper frame body 20 and the left and right side walls 42 of the lower frame body 40, locking means 32 for limiting the upward movement amount of the upper frame body 20 is formed. Has been. Specifically, the locking means 32 includes a locking claw 22b formed on the left and right side walls 22 of the upper frame body 20 and a locking claw 42b formed on the left and right side walls 42 of the lower frame body 40, The locking claws 22b and 42b are locked so as to limit the amount of upward movement of the upper frame body 20 when the urging force of the urging means 12 acts on the upper frame body 20 via the wire heating element 11. It is possible.

  By providing the lower frame body 40 in this manner and limiting the amount of movement of the upper frame body 20 upward, even if the heat sink 30 is warped upward as shown in FIG. The wire heating element 11 and the upper frame body 20 are made to follow the movement of the lower surface 30a of the heat radiating plate 30, and the contact state between the line heating element 11 and the upper frame body 20 is limited to the upper limit movement restriction position of the upper frame body 20. The urging force that is possible to maintain the close contact state between the upper frame body 20 and the heat radiating plate 30 can be secured. Further, since the lower frame body 40 is fixed to the support base B, even if an external force is applied to the device 1, the linear heating element 11 disposed between the upper frame body 20 and the lower frame body 40 is not affected. Misalignment can be prevented.

  In the illustrated example, a heat-dissipating silicone coating film (not shown) is formed between the top plate upper surface 21 a and the heat radiating plate lower surface 30 a of the upper frame 20. With this coating film, even when fine irregularities exist on the surfaces of the top plate upper surface 21a and the heat sink lower surface 30a, the gap can be filled and high thermal conductivity can be maintained. When the coating film has adhesiveness, the followability of the upper frame body 20 can be further improved with respect to the movement of the radiator lower surface 30a even when the radiator plate 30 is warped upward due to heat generation. it can.

  In the illustrated example, the vertical compression amount t3 of the urging means 12 (see FIG. 2), that is, a state before the wire heating element 11 and the heat radiating plate 30 are disposed above (the urging means 12 is in an unloaded state). ), The vertical compression amount t3 of the urging means 12 until the lower end 22a of the left and right side walls 22 of the upper frame body 20 abuts against the support base B after the linear heating element 11 and the heat radiating plate 30 are disposed above. The amount of upward movement of the upper frame body 20 is larger than the maximum upward warping amount t1 (see FIG. 3) of the heat dissipation plate 30 due to thermal expansion caused by the heat generation of the wire heating element 11. Limited by.

  That is, in this snow melting apparatus 1, the locking means 32 causes the upward compression amount t3 of the urging means 12 to be larger than the maximum upward warping amount t1 of the heat sink 30. Since the movement amount is limited, the maximum warpage amount t1, the limited movement amount t2 of the upper frame 20 from the state where the lower end 22a is in contact with the support base B to the movement limit position of the upper frame, and the urging means The relationship between the compression amount t3 of 12 in the vertical direction is the maximum warpage amount t1 <the limit movement amount t2 <the compression amount t3.

  By configuring the snow melting device 1 so as to satisfy such a relationship, even when the upward warping amount of the heat radiating plate 30 is maximized, the urging force to the linear heating element 11 by the urging means 12 is ensured. It is possible to maintain the close contact state between the wire heating element 11 and the upper frame body 20 and the close contact state between the upper frame body and the heat sink, and the heat conduction efficiency of the snow melting device 1 can be suppressed from decreasing. .

For example, a line heating element 11 having nine straight portions 11a at equal intervals along the length direction is arranged on an aluminum heat sink 30 having a width of 582 mm and a length of 1972 mm, and the snow melting device 1 is operated. In this case, assuming that the temperature of the heat sink 30 is about 5 ° C. higher than the support base B, the linear expansion coefficient of aluminum is 2.3 × 10 ⁻⁶ (K ⁻¹ ). The upward maximum warping amount t <b> 1 is about 1.4 mm at the center of the heat sink 30. In such a case, if the limit movement amount t2 is set to 1.5 to 2 mm and the compression amount t3 is larger than 2 mm so as to satisfy the relationship of maximum warpage amount t1 <limit movement amount t2 <compression amount t3, heat dissipation Even if the warpage of the plate 30 occurs, the thermal coupling between the heat sink lower surface 30a and the upper surface of the wire heating element 11 is not impaired, and a good close state can be maintained.

The principal part top view which represented typically the snow melting apparatus which concerns on this embodiment. The schematic cross section of the AA line of FIG. Sectional drawing when a heat sink warps by thermal expansion from the state of FIG. The schematic cross section of the conventional snow melting apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Snow melting apparatus, 11 ... Linear heating element, 11a ... Linear part, 11b ... Curved part, 12 ... Energizing means, 20 ... Upper frame, 21 ... Top plate, 21a ... Top plate upper surface, 21b ... Top plate lower surface, 22 ... side wall, 22a ... lower end, 22b ... locking claw, 30 ... heat radiating plate, 30a ... heat sink lower surface, 32 ... locking means, 40 ... lower frame, 41 ... bottom plate, 42 ... side wall, 42b ... locking claw , B: Support base, t1: Maximum upward warping amount of the heat sink, t2: Limit movement amount of the upper frame, t3: Compression amount in the vertical direction of the urging means

Claims (4)

A snow melting device having a configuration in which a wire heating element and a biasing means for biasing the wire heating element upward are arranged between a support base and a heat sink,
An upper frame that covers at least the linear portion of the linear heating element from above, and a lower frame disposed below the upper frame ,
The upper frame has a top plate and left and right side walls located between the heat radiating plate and the wire heating element,
The lower frame has a bottom plate located between the support base and the urging means, and left and right side walls located inside the left and right side walls of the upper frame,
By urging the wire heating element upward by the urging means, it is possible to maintain a posture in which the wire heating element is in contact with the lower surface of the top plate of the upper frame and the upper surface of the top plate is in contact with the lower surface of the heat sink. ,
When the downward load is applied to the heat radiating plate, the upper frame body is configured to move downward by compressing the urging means . The upper ends of the left and right side walls of the lower frame body are not in contact with the top plate of the upper frame body, and the lower ends of the left and right side walls of the upper frame body are regulated by contacting the support base. A snow melting device. Between the left and right side walls of the left and right side walls and the lower frame body before Symbol upper frame, characterized in that the locking means for limiting the amount of upward movement of the upper frame member is formed The snow melting device according to claim 1.   The amount of compression in the vertical direction of the urging means when the lower ends of the left and right side walls of the upper frame body come into contact with the support base is the maximum upward warping of the heat radiating plate due to thermal expansion caused by the heat generation of the linear heating element. The snow melting device according to claim 2, wherein an amount of upward movement of the upper frame body by the locking means is limited so as to be larger than the amount.   The snow melting device according to any one of claims 1 to 3, wherein a coating film is formed between an upper surface of the top frame and a lower surface of the heat sink.

Images