Abstract: A sealed, closed end heat pipe efficiently warms the drain for an evaporator so that condensation may flow unobstructed away from the evaporator in the refrigeration circuit. An evaporator end of the heat pipe is exposed to ambient air and a condenser end is located close to the drain inlet adjacent the evaporator. Thus, no external power source is required as fluid within the evaporator end is heated to vapor phase and circulates toward the condenser end, and cooled fluid from the condenser end returns to the evaporator end.

Abstract: A hot gas defrost system for a refrigeration cycle, including at least one compressor, condenser, receiver, expansion valve and evaporator. During defrost, a pressure-sensitive valve to the condenser inlet is normally closed, and the flow of refrigerant from the compressor bypasses the condenser and flows to the receiver. However, when the pressure in the system reaches a critical point, the pressure-sensitive condenser inlet valve will open to release the excessive pressure. The condenser inlet valve is also temperature-sensitive and will open if the ambient temperature surrounding the condenser is above a specific point. Opening of the condenser valve permits the utilization of the hot gas in the condenser for defrost and to decrease the thermal shock resulting from the superheated vapor contacting the evaporator coil. The compressor, which needs a constant flow of liquid refrigerant for cooling, is continually supplied with liquid refrigerant.

Abstract: Leaks in tube bundles for a heat exchanger are eliminated or minimized by tube interrelated techniques. A floating tube bundle is constructed with separate support elements also secured to the heat dissipating fins and extending through and supported by the support plates. Thin-walled copper tubing similar to that used for the fluid-carrying tubes is used as support tubes, and steel rods are inserted into these support tubes to provide the necessary strength. To minimize leakage in the area where the tube bundle is joined to a header, connector tubes are provided that have one end joined to the header and the other end extending into one of the tubes of the tube bundle sufficiently far that the end of the connector tube passes through the support plate and at least one fin.

Abstract: Circumferentially spaced bosses concentrically position a male tube end within a female tube end. The bosses have a preferred shape which permits molten brazing material to flow evenly between the tubes, ensuring a void-free joint. The bosses provide a relief clearance at the mouth of the male tube to allow the formation of a continuous annular band of brazing material at this end. Stop tapers on the bosses allow the female tube to be pressed onto the male tube for stability prior to brazing. The bosses also limit the overlap of the two tubes to a maximum distance, ensuring adequate heat conduction to the innermost portion of the male tube. Spacers, integral with the bosses, form an axial gap between the tubes into which the brazing rod more readily melts.

Abstract: An evaporative condenser having a cylindrical fiberglass housing which provides a circumferential air flow across a plurality of concentrically oriented spiral condensing coils. The planar spiral coils are generated through the compression of a conical winding of tubing formed about a multi-tiered platform, to form an evenly-spaced spiral condensing coil. Each layer of tubing is affixed to a plurality of radial braces, which provide the evaporative coils with sufficient structural integrity to be individually employed. A method and apparatus for producing spiral coils having uniform spacing between adjacent revolutions.