Method utilizing a porous vitreous carbon body particularly for fluid heating

• US 4,334,350 A
• Filed: 03/07/1980
• Issued: 06/15/1982
• Est. Priority Date: 07/26/1978
• Status: Expired due to Term

• Current Assignee: Chemotronics International Incorporated Shareholders
• Original Assignee: Chemotronics International Incorporated Shareholders
• Inventors: Franklin, Charles H., Vinton, Clarence S., Rice, Warren A., Torbett, Christopher J.
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Arbes, Carl J.
• Application Number:
  US06/128,191
• Time in Patent Office: 830 Days
• Field of Search: 29/611, 29/613, 29/619, 29/419 R, 29/419 G, 338/114, 338/208, 219/338, 219/552, 219/553, 219/381, 219/382, 228/209
• US Class Current: 29/611
• 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: H01C 7/00 Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material consisting of loose powdered or granular material H01C8/00; resistors having potential barriers, e.g. field-effect resistors, H01L29/00; semiconductor devices sensitive to electromagnetic or corpuscular radiation, e.g. photoresistors, H01L31/00; magnetic field controlled resistors H10N50/10; bulk negative resistance effect devices H10N80/00
• CPC Class Codes: H05B 3/145 Carbon only, e.g. carbon black, graphite
• CPC Class Codes: Y10T 29/49083 Heater type
• CPC Class Codes: Y10T 29/49098 Applying terminal

Abstract

A method for the heating of a fluid stream flowing in the pores of a body of specially prepared porous reticulated vitreous carbon which does not crack or substantially change in electrical resistance with time when heated to elevated temperature in air is described. The body is composed of electrically conductive rigid, interconnected and multidirectional continuous strands of vitreous carbon forming a rigid porous, three dimensional skeletal structure. The body as an electrical resistance element has current conductive paths between at least two regions; is shaped to provide particular cross-sections along the conductive paths; and has electrical connector means attached at the regions of the body so that current can be distributed through the body. The electrical resistance element is particularly useful as a heating element for air flowing through the pores in electrically powered room space heaters, hair dryers, hand dryers and the like and can also function as a self-cooling resistor. In a like manner, electromagnetic energy is used to heat a body of the porous vitreous carbon so as to heat a fluid stream flowing through the pores.

Claims

1. A method for the preparation of an electrical resistance element which comprises:

(a) shaping a rigid body of interconnected, multidirectional, continuous strands of reticulated vitreous carbon forming a rigid, porous, three dimensional skeletal structure to provide current conductive paths between at least two regions of the body, said body having been heat treated at least about 1800°

C. in a non-reactive atmosphere; and

(b) mounting at least two electrical connector means to the body at the regions so that an electrical current can flow through the body.