Abstract In line water heating apparatus comprising a cylindrical heating element positioned within a length of vertical helically corrugated tubing is compact in size, low in cost and very efficient in transferring heat to the water. The outer surface of the cylindrical heating element is uniformly spaced from the innermost portions of the corrugations along its entire length by a slight distance therefrom which is less than the depth of the corrugations. The internal helical tube corrugations cause a portion of the water entering at the bottom to tend to travel in a spiral, thus lengthening its contact path with the heater element before it is drawn off at the top of the apparatus. However, their main purpose is to induce turbulent flow conditions in the water and thus enhance the rate of heat transfer. Since the corrugated tube is spaced from the heater core, the water can also circulate and maintain its temperature when the valve is closed. A dual mode temperature control permits the small supply of water which is always present in the device to be maintained at a temperature somewhat less than the desired temperature so that water leaving the apparatus can very quickly be brought to its maximum and so that randomly drawn off single cups of water will be at a sufficiently hot temperature.
In line heater apparatus for providing an instantaneous supply of hot water comprises a length of helically corrugated tubing positioned in surrounding, spaced relation to an axially positioned cylindrical heater element mounted on one of first and second end members positioned at each end of sAid tubing and integrally attached thereto, means on said first end member for attaching the apparatus to a water supply line, means on said second end member for attaching the apparatus to a valve controlled dispensing line, temperature control means mounted in said second end member for controlling the operation of said heater element, said cylindrical element extending for substantially the entire length of said corrugated tubing and the outer surface of the cylindrical heater element being uniformly spaced from the innermost portions of the corrugations along its entire length by a slight distance therefrom which is less than the depth of the corrugations, the spacing being sufficient that water flowing from one end of said tubing to the other will flow in a generally helical path through the corrugations and in a generally axial direction in said space and in turbulent contact with said cylindrical heating element.
Claim 2
Dependent Claim
193 words
In line heater apparatus for providing an instantaneous supply of hot water comprises a length of helically corrugated tubing positioned in surrounding, spaced relation to an axially positioned cylindrical heater element mounted on one of first and second end members positioned at each end of sAid tubing and integrally attached thereto, means on said first end member for attaching the apparatus to a water supply line, means on said second end member for attaching the apparatus to a valve controlled dispensing line, temperature control means mounted in said second end member for controlling the operation of said heater element, said cylindrical element extending for substantially the entire length of said corrugated tubing and the outer surface of the cylindrical heater element being uniformly spaced from the innermost portions of the corrugations along its entire length by a slight distance therefrom which is less than the depth of the corrugations, the spacing being sufficient that water flowing from one end of said tubing to the other will flow in a generally helical path through the corrugations and in a generally axial direction in said space and in turbulent contact with said cylindrical heating element.
Claim 3
Dependent Claim
47 words
The heater apparatus of claim 1 wherein a braided metal sleeve surrounds said corrugated tubing and is welded to said first and second end members, said braided sleeve serving to prevent elongation of the tubing due to increases in the pressure of the fluid within the system.
Claim 4
Dependent Claim
20 words
The heater apparatus of claim 1 wherein the tubing, end members and braided sleeve are each formed of stainless steel.