Electric Heating Device with Tolerance PTC Heating Element

• US 20070114217A1
• Filed: 11/10/2006
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Catem GmbH & Co., KG
• Original Assignee: Catem GmbH & Co., KG
• Inventors: Bohlender, Franz, Walz, Kurt
• Granted Patent: US 7,667,164 B2
• Time in Patent Office: Days
• US Class Current: 219/202
• 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 3/0429 For vehicles
• CPC Class Codes: F24H 3/0435 Structures comprising heat spreading elements in the form of fins
• CPC Class Codes: F24H 3/0464 Two-piece frames, e.g. two-shell frames, also including frames as a central body with two covers
• CPC Class Codes: F24H 3/0476 Means for putting the electric heaters in the frame under strain, e.g. with springs
• CPC Class Codes: F24H 9/1872 PTC

Abstract

For avoiding the selection and storage of PTC heating elements with different departures from rated heating power, additional tolerance PTC heating elements are held ready which uniformly have a lower rated heating power, preferably one half or third of the rated heating power, compared to the standard or primary PTC heating element. By the use of a second standardized heating element, i. e. the tolerance PTC heating element, the storage of a high number of PTC heating elements with different departures can be dispensed with and a cheaper manufacture can be permitted.

Claims

1. An auxiliary electric heater for a motor vehicle, comprising:

a plurality of heat stages with at least one PTC heating element each, all of the PTC heating elements having the same, first rated heating power, and

a plurality of radiator elements for dissipating the generated heat to a medium flowing through the radiator elements,

wherein

at least one of the heat stages contains a tolerance PTC heating element with a second rated heating power for correcting departures of the heating power of the at least one PTC heating element from the first rated heating power due to differences in manufacture, the second rated heating power being lower than the first rated heating power.

2. The electric heater according to claim 1, wherein the second rated heating power is a fraction of the first rated heating power.

3. The electric heater according to claim 1, wherein the second rated heating power is one of one half, one third, and one quarter of the first rated heating power.

4. The electric heater according to claim 1, wherein the dimensions of the tolerance PTC heating element approximately correspond to those of the PTC heating elements with the first rated heating power.

5. The electric heater according to claim 1, wherein the tolerance PTC heating element has the same thickness as the PTC heating elements with the first rated heating power.

6. The electric heater according to claim 5, wherein the tolerance PTC heating element has the same length as the PTC heating elements with the first rated heating power.

7. The electric heater according to claim 5, wherein the tolerance PTC heating element has the same width as the PTC heating elements with the first rated heating power.

8. The electric heater according to claim 1, wherein the first rated heating power has a value of between 50 Watts and 100 Watts.

9. The electric heater according to claim 1, wherein the PTC heating elements are arranged in levels in a layered structure of PTC heating elements and radiator elements.

10. The electric heater according to claim 9, wherein the PTC heating elements are held in a common level in positioning frames.

11. The electric heater according to claim 10, wherein each positioning frame comprises openings only for the PTC heating elements with the first and second rated heating powers required in each case.

12. The electric heater according to claim 9, wherein, in each of the levels, a pre-determined number of spaces for PTC heating elements is provided, and in one level for PTC heating elements with the first and the second rated heating powers not required, spaces are filled with dummy elements.

13. The electric heater according to claim 1, wherein the auxiliary electric heater is designed for voltages lower than 120V.

14. An auxiliary electric heater for a motor vehicle, comprising:

a plurality of heat stages each having at least one primary PTC heating element each, all of the primary PTC heating elements having the same, first rated heating power, wherein at least one of the heat stages contains a tolerance PTC heating element with a second rated heating power, the tolerance PTC heating element correcting departures of the heating power of the at least one primary PTC heating element from the first rated heating power, the second rated heating power being lower than the first rated heating power, and

a plurality of radiator elements that dissipate the heat generated by the heat stages to a medium flowing through the radiator elements.

15. The auxiliary electric heater according to claim 14, wherein the second rated heating power is no more than one half of the first rated heating power.

16. The auxiliary electric heater according to claim 15, wherein the second rated heating power is no more than one quarter of the first rated heating power.

17. The auxiliary electric heater according to claim 14, wherein the dimensions of the tolerance PTC heating element at least approximately correspond to those of each of the primary PTC heating elements.

18. The auxiliary electric heater according to claim 14, wherein the first rated heating power has a value of between 50 Watts and 100 Watts.

19. The auxiliary electric heater according to claim 14, wherein the PTC heating elements and the radiator elements are arranged in alternating layers.

20. The auxiliary electric heater according to claim 14, wherein the auxiliary electric heater is designed for voltages lower than 120V.

21. A process comprising the steps of:

a. assembling an electric heater to form a layered structure of a plurality of alternating levels of PTC heating elements and radiator elements, wherein each of the levels with PTC heating elements comprises at least one primary PTC heating element, and wherein all of the primary PTC heating elements have the same, first rated heating power; and

b. compensating for departures from an actual heating power of the PTC heating elements of each level by inserting at least one tolerance PTC heating element in the level, the tolerance PTC heating element having a second rated heating power that is lower than the first rated heating power.

22. The process according to claim 21, wherein the correcting step comprises, for each level, at least one of 1) replacing a primary PTC heating element with a tolerance PTC heating element and 2) inserting a tolerance PTC heating element in the level.

23. The process according to claim 21, wherein the primary and tolerance PTC heating elements have essentially have the same dimensions.