Abstract: A heat exchanger having an outer shell member and having a helically wound volute member which is double walled and includes a finned outer tube and a close-fitting inner tube, and the heat exchanger further including a core member which extends through the helical volute member and closes its central aperture to confine the flow of liquid in the outer shell member to flow through the fins, rather than pass through the aperture through the center of the helical volute member. The fins on the double walled volute member are wound as close to touching the core member as possible and the diameter of the core member and of the outer shell member is such that the fins closely fit the space between them. Both the finned tube and the inner tube pass completely through the shell member, and the finned outer tube is soldered to the shell so that any leakage between the tubes will pass outside the heat exchanger shell member rather than mixing the heat exchanger liquids.

Abstract: A heat exchanger having an outer shell member and having a helically wound volute member which is double walled and includes a finned outer tube and a close-fitting inner tube, and the heat exchanger further including a core member which extends through the helical volute member and closes its central aperture to confine the flow of liquid in the outer shell member to flow through the fins, rather than pass through the aperture through the center of the helical volute member. The fins on the double walled volute member are wound as close to touching the core member as possible and the diameter of the core member and of the outer shell member is such that the fins closely fit the space between them. Both the finned tube and the inner tube pass completely through the shell member, and the finned outer tube is soldered to the shell so that any leakage between the tubes will pass outside the heat exchanger shell member rather than mixing the heat exchanger liquids.

Abstract: A heat exchanger having an outer shell which is long as compared with its diameter and having a helical double-walled finned volute member which is wound to a small diameter around a core member, the proportions being such that the fins on the double-walled member touch the core on the inside of the wound convolutions and touch the shell on the outside of the wound convolutions. The tube which comprises the outer wall of the double-walled member extends through the shell so that any leakage into the space between the inner and outer tubes of the double-walled tube member will be discharged outside of the shell. The process by which the exchanger is made includes the steps of inserting an inner tube in a length of finned outer tube, winding them into a volute member, inserting a central core member therein, installing these members in a shell member and spinning the shell member closed to seal with the ends of the outer tubing of the volute member.

Abstract: A knock-down tank for containing a liquid medium having a bottom panel, multiple side panels and a top panel secured together by fasteners inside the tank and insulated against heat transfer, the tank being made liquid tight by a plastic liner, and the top panel supporting a depending dip tube assembly whose tubes provide the only access to the liquid contained within the liner.

Abstract: An interface circuit for adding a solar heat system to a building having a building heating and cooling system and having a building thermostat system, the interface circuit being especially wired to be compatibly interposed between the building thermostat system and the building heating and cooling system without rewiring the latter and being also connected to the solar heat system, the interface circuit thereby adding the solar system as a heat source, and the interface circuit automatically substituting the solar source for the building heating system when heat is called for at a level within the capability of the solar system to supply.

Abstract: Solar heat collector apparatus wherein each solar collector unit comprises a modular collector box having multiple collector tubes with their respective inlet and out ends grouped together and connected to an inlet manifold pipe and an outlet manifold pipe, the manifold pipes being outside the box and axially aligned with their bores non-communicating, several collector boxes being placed together side-by-side with their aligned manifolds interconnected, and the boxes having covers which completely enclose the manifold pipes and have no connections to external fluid circuitry exposed.