The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 1977
Filed:
Dec. 22, 1975
Alben C Boggs, Pittsburgh, PA (US);
Robert D Shirey, Pittsburgh, PA (US);
Emerson Electric Co., St. Louis, MO (US);
Abstract
Our invention relates to electric heating elements for heating liquid within a tank, and particularly to heating elements for use in domestic commercial water tanks, wherein the element comprises a metal mounting member secured to the wall of the tank and a sheath portion carried by the mounting member and extending through a hole in the tank wall for immersion in the water in the tank. The sheath portion contains a resistance conductor and insulation which electrically insulates the conductor from the sheath, so that water in the tank is heated when the resistance conductor is electrically connected to a source of electrical energy. Our invention provides means for protecting the electric heating element from damage which may otherwise be caused by a sudden surge of high voltage, such as that which may be caused by lightning disturbances in the immediate vicinity.