Ptc heater radiator with frame members applying pressure to heaters

• US 5,562,844 A
• Filed: 12/05/1994
• Issued: 10/08/1996
• Est. Priority Date: 06/23/1992
• Status: Expired due to Term

• Current Assignee: David & Baader - DBK- Spezialfabrik Elektrischer Apparate und Heizwiderstande GmbH
• Original Assignee: David & Baader - DBK- Spezialfabrik Elektrischer Apparate und Heizwiderstande GmbH
• Inventors: David, Josef, Bohlender, Franz
• Primary Examiner(s): Jeffery, John A.
• Application Number:
  US08/349,457
• Time in Patent Office: 673 Days
• Field of Search: 219/202, 219/530, 219/540, 219/504, 219/505, 392/379, 392/360, 392/365
• US Class Current: 219/540
• CPC Class Codes: F24H 3/0405 using electric energy supply, e.g. the heating medium being a resistive element; Heating by direct contact, i.e. with resistive elements, electrodes and fins being bonded together without additional element in-between F24H3/06, F24H3/08, F24H3/10 take precedence
• CPC Class Codes: F24H 9/1863 Arrangement or mounting of electric heating means
• CPC Class Codes: F24H 9/1872 PTC
• CPC Class Codes: F28F 9/001 Casings in the form of plate-like arrangements; Frames enclosing a heat exchange core

Abstract

In an electric radiator having a frame in which an arranged heat output elements, which include PTC resistors, and heating elements including fins, which abut on these heat output elements. The heating elements are supported by two oppositely disposed frame bars in such a way that they apply pressure to the heat output elements, said frame bars including rails having a U-shaped cross-section with flat legs extending from a central leg which is provided with longitudinally extending bulging portions separated from the central leg to impart spring properties to said bulging portions which is applied to the heating elements.

Claims

1. A radiator comprising:

a holding frame having interconnected pairs of each of first bars extending in a first direction and second bars extending generally transverse to said first bars

a plurality of elongate electric heating elements extending between said second bars generally parallel to said first bars arranged in stacked planes extending generally parallel to said first bars and;

a plurality of heat-conducting elements arranged in parallel rows each said heat conducting element located between adjacent heating elements, each of said heat-conducting elements including at least one sheet-metal strip of fins extending substantially in a zigzag shape and including substantially straight portions between upper and lower reversing portions, at least one row of reversing portions located adjacent a heating element plane and receiving heat from it,

at least one of said first bars including means for applying a mechanical bias pressure between said at least one first bar and the heat-conduction elements to effect transfer of heat from a heating element to said at least one row of reversing portions of a heat conducting element, said mechanical pressure applying means including an elongated rail of resilient material of essentially U-shaped cross-section with side legs depending from a central leg having in the central area of its cross-section a plurality of elongated bulging portions along its length which project from said U-shaped cross-section central leg toward said heat conducting elements.

2. A radiator according to claim 1, wherein the bulging portions project beyond the plane defined by the outer surface of the central leg by a distance corresponding substantially twice the thickness of the material of said central leg.

3. A radiator according to claim 1 wherein the bulging portions have a length corresponding approximately to the length of the heating elements which have pressure applied thereto by said bulging portions.

4. A radiator according to claim 1, wherein the lateral legs of the first bars are bent inwards and downwards at their upper ends.

5. A radiator according to claim 4, wherein the inwardly directed portions of the lateral legs end at a distance above the central leg.

6. A radiator according to claim 4, wherein the free edges of the inwardly directed portions of the lateral legs are located above the cut lines of the bulging portions.

7. A radiator according to claim 1, further comprising a rail having an approximately M-shaped cross-section arranged in the free space between the legs of each of said first bars the outer legs of said rail fastened to the lateral legs of the associated bar.

8. A radiator according to claim 1, wherein

the rails defining said first bars have at each of their two ends an extension of the central leg in the form of a flat leg extending tongue whose free end is directed towards the center of the bar cut and bent out, said tongue projecting in the direction in which the lateral legs extend above the central leg of the rail, and

the second bars have in each of their two end sections shoulders which extend over the lugs and which are locked in position behind the tongues, each of said shoulders being provided with a projection directed towards the center of said first bars and which rests on the central leg and supports said central leg against the resilient force created by said bulging portions.

9. A radiator according to claim 1, wherein each of the heat-conducting elements comprises two plane-parallel spaced sheet-metal strips arranged point-symmetrically with respect to each other and angled twice at one end thereof to define the mutual distance between the plane-parallel section which have the strip of fins arranged between them.

10. A radiator according to claim 9, wherein in the plane-parallel area, the edges of the sheet-metal strips are flanged towards the strip of fins to protect said strip of fins against lateral displacement between the plane-parallel sections of said sheet-metal strips.

11. A radiator according to claim 9, wherein the strip of fins of each heat conducting element is insulated from the sheet-metal strips by an electrically insulating foil having thermal conductivity.

12. A radiator according to claim 1 wherein the heating elements are of the positive temperature coefficient type held in a frame with cut-out portions for receiving therein said heating elements, which are held in said frame, the thickness of said frame being smaller than that of said heating elements.

13. A radiator according to claim 12, wherein the longitudinal edges of the frame are provided with an edge of increased height to protect the heat conducting elements against lateral displacement.

14. A radiator according to claim 13, wherein the edges of the frame are increased in height to an extent that the sheet-metal strips are protected against manual contact.

15. A radiator according to claim 12, wherein the heating elements are protected against environmental influences by a casting compound.

16. A radiator according to claim 1, wherein portions of the sheet metal strip of fins each is essentially flat and has two adjacent reversing portions that laterally contact one another.

17. A radiator according to claim 1, wherein the lateral legs of the first bars are bent in a beadlike manner at their edge followed by an inner portion.

18. A radiator according to claim 17, wherein, at their outer ends, the first two bars are held together by sheet-metal strips for taking up the forces created by said bulging portions.