Patent ID: 7318735

Claim:
A heater, comprising: a tank; a header plate mounted to one end of the tank, the header plate having a plurality of holes therethrough; a plurality of heater tubes mounted to the header plate and extending into the tank, each heater tube having at least one open end in registry with one of the holes, each heater tube containing an electrical resistance heater wire surrounded by electrical insulation; a standoff plate mounted to an exterior side of the header plate, the standoff plate having a plurality of holes, each of which registers with one of the holes in the header plate; a plurality of standoff tubes, each of the standoff tubes having an end secured to the standoff plate, each of the standoff tubes registering with one of the holes in the header plate; an electrical conductor within each of the standoff tubes, each electrical conductor being electrically connected to one of the heater wires; a standoff housing having a base containing a plurality of holes, each of the standoff tubes having another end mounted to the base of the standoff housing in registry with one of the holes in the base of the standoff housing, the electrical conductors in the standoff tubes extending through the holes in the base of the standoff housing for connection to electrical power wiring; and wherein detaching the standoff plate from the header plate allows the standoff housing, standoff plate and standoff tubes to be removed as a unit from the tank.