Abstract: An electric water heater has a tubular side port insert, projecting into the interior of the filament-wound plastic tank portion of the water heater tank, operative to conduct tank water heat to an external temperature controller. The insert has a tubular base extending through the tank wall and circumscribing a cold pin portion of an electrical resistance type heating element extending into the tank, and a hood portion forming a horizontally inward extension of the insert base and extending along only a top side portion of the element in an upwardly spaced relationship therewith so that no portion of the insert extends beneath the active portion of the heating element. In this manner, scale forming on the active portion of the element, and falling therefrom, does not become trapped between the heating element and the side port insert, and overshoot of the controlled tank water temperature is substantially reduced.

Abstract: A liquid heating appliance, representatively a water heater, is provided with protective apparatus for preventing rupture of its liquid storage tank portion caused by overheating of pressurized liquid therein. Illustratively, the protective apparatus includes a length of thermoplastic tubing, preferably polybutylene tubing, whose interior is exposed to the tank interior so as to be pressurized by heated liquid therein. In the event of a liquid overheating condition in the tank, the tubing is heat-softened in a manner reducing its burst pressure and causing it to burst, at a pressure substantially below the tank burst pressure, and thereby form a pressure relief outlet passage for the tank. A shield structure with at least one fluid outlet opening therein extends outwardly around the thermoplastic tubing to diffuse pressurized fluid escaping from the burst tubing.

Abstract: An electric water heater has a tubular side port insert, projecting into the interior of the filament-wound plastic tank portion of the water heater tank, operative to conduct tank water heat to an external temperature controller. The insert has a tubular base extending through the tank wall and circumscribing a cold pin portion of an electrical resistance type heating element extending into the tank, and a hood portion forming a horizontally inward extension of the insert base and extending along only a top side portion of the element in an upwardly spaced relationship therewith so that no portion of the insert extends beneath the active portion of the heating element. In this manner, scale forming on the active portion of the element, and falling therefrom, does not become trapped between the heating element and the side port insert, and overshoot of the controlled tank water temperature is substantially reduced.

Abstract: A liquid heating appliance, representatively a water heater, is provided with protective apparatus for preventing rupture of its liquid storage tank portion caused by overheating of pressurized liquid therein. Illustratively, the protective apparatus includes a length of thermoplastic tubing, preferably polybutylene tubing, whose interior is exposed to the tank interior so as to be pressurized by heated liquid therein. In the event of a liquid overheating condition in the tank, the tubing is heat-softened in a manner reducing its burst pressure and causing it to burst, at a pressure substantially below the tank burst pressure, and thereby form a pressure relief outlet passage for the tank. A shield structure with at least one fluid outlet opening therein extends outwardly around the thermoplastic tubing to diffuse pressurized fluid escaping from the burst tubing.

Abstract: A filament-wound tank portion of an electric water heater has a wall opening through which an electric heating element of other structure extends into the interior of the tank. The opening is reinforced by a stacked series of single layer, open weave patch members which are interdigitated with layers of the filament winding and through which the opening extends. The filament winding and the patches are impregnated with and intersecured by a cured resin material. As an alternative to cutting portions of the patches during formation of the tank wall opening, the patches may be provided with suitable pre-formed openings with reinforced peripheries, the subsequently formed tank wall opening extending through these reinforced, pre-formed patch openings. The single layer, open weave patches are also utilized to reinforce other types of filament-based tank wall structures.

Abstract: An electric water heater has a tank portion in which water to be heated is stored. The stored water is heated by a vertically spaced plurality of electric heating elements extending into the tank interior. The heating elements are of unequal wattages, and serve unequal volume water zones, but provide equal heating wattage densities in each of the water zones.

Abstract: An improvement in electrical elements for a water heater includes a mass attached to the element for reducing the deposition of hard water scale on element surfaces, particularly in the return bend areas. In one embodiment, a flow accelerator tube encloses the element. The flow accelerator tube has an inlet at one end and an outlet at a higher elevation at the opposite end. Water is induced to flow through the tube because of temperature change. In another embodiment, a solid mass with high surface area encloses the return bend areas to increase heat transfer at a lower temperature to reduce scaling and increase element life.

Abstract: An improvement in electrical elements for a water heater includes a mass attached to the element for reducing the deposition of hard water scale on element surfaces, particularly in the return bend areas. In one embodiment, a flow accelerator tube encloses the element. The flow accelerator tube has an inlet at one end and an outlet at a higher elevation at the opposite end. Water is induced to flow through the tube because of temperature change. In another embodiment, a solid mass with high surface area encloses the return bend areas to increase heat transfer at a lower temperature to reduce scaling and increase element life.

Abstract: An extended life electrical heating element for a water heater includes a coiled heating resistance wire having a uniform power output per coil turn. Where the heating resistance wire passes through the sheath at critical areas, e.g. return bends, the number of coil turns per unit length of element is reduced to reduce thermal power output per unit length of the element. The number of coil turns per unit length of element in bend areas may be reduced by simply stretching the coiled heating wire to attain the desired length of resistance wire per unit length of the element. Resistance wires of differing heat output per unit length may be combined with different degrees of stretching to achieve the desired element temperatures. The reduced power at the bend portions reduces element temperature to reduce hard water scaling and significantly extend the life of the element.

Abstract: A control/safety apparatus and method for an electrical or fuel fired water heater includes one or more temperature sensors strategically located on the water heater vessel at a level at or above a critical water level. The time rate of temperature change is calculated from the sensed temperature. An abnormal value of temperature change rate corresponding to an insufficient water level deactivates the heater to prevent damage to the heater. Water level, projected heating times, heater malfunctions and other operating parameters may be calculated or detected based on the time rate of change in sensed temperature.

Abstract: An improved burner for heating water in a hot water system is provided. This burner includes an inlet tube having flared ends and a constricted middle portion to provide an increased amount of air into the barrier. The burner also includes a barrel which communicates with the inlet tube to receive fuel gas and air from it. It vents this air and fuel gas mixture through a large number of ports formed through its sidewalls and arranged in a predetermined pattern to produce a continuous combustion layer when the user ignites the venting mixture. These ports have a width substantially smaller than their length and they produce small, nonluminous, bluish flames which form the combustion layer. This combustion layer burns hot to raise the temperature of the barrel segments surrounding the ports to a level at which the segments glow red and emit infrared heat.

Abstract: A disposable or reusable "crawl resistant" flexible mattress formed of panels sealed together to define alternately inflatable passages between the panels for sequentially supporting structure for a long term bed patient to reduce decubitus ulcers, bed sores, etc. The mattress has vent holes in its top for ventilating the patient with inflation gas and a crawl resistant layer bonded to a bottom of the mattress to prevent the mattress from "crawling" relative to the bed and patient during use. In one form of the mattress, crawling is reduced by a separation between the inflation passages so individual sections of the mattress can more readily conform to a patient's body contour.

Abstract: A compact low-resistance muffler for reducing sound levels generated by the pulsatile flow of fluids as, for example, at the intake of a compressor or the exhaust port of an internal combustion piston engine. The muffler or suppressor comprises a pair of adjacent branch passages having a common inlet trunk and a common outlet trunk, one of the branch passages containing a flow-restricting orifice and the other of such branch passages being free of any such restriction.

Abstract: A disposable or resuable "crawl resistant" flexible mattress formed of panels sealed together to define alternately inflatable passages between the panels for sequentially altering supporting structure for a long term bed patient to reduce decubitus ulcers, bed sores, etc. The mattress has vent holes in its top for ventilating the patient with inflation gas and a crawl resistant layer bonded to a bottom of the mattress to prevent the mattress from "crawling" relative to the bed and patient during use. In one form of the mattress, crawling is reduced by a separation between the inflation passages so individual sections of the mattress can more readily conform to a patient's body contour.

Abstract: An apparatus and method are disclosed for promoting the evaporation of perspiration from an absorbent sheet of foam or other material covering an inflatable-deflatable patient-supporting bed pad. The pad has a multiplicity of perforations in its top wall which communicate with a pair of interlaced passages or chambers within the pad. By pulsing the air supplied alternately to each chamber of the pad at a frequency within the range of about 15 to 65 pulses per second, the perforations provide a multiplicity of tiny puffing or pulsing jets of air into the foam sheet to promote the evaporation of moisture from that sheet. Means for overlapping the inflation-deflation cycles is also disclosed.