Abstract: A heat exchanger includes a plurality of longitudinally-extending first channels and a plurality of second channels fluidly isolated from the plurality of first channels. Each first channels includes a plurality of spiraling internal fins and a plurality of external fins. The internal fins extend from and are integrally formed with the internal walls of the first channel. The external fins connect extend from and are integrally formed with the external walls of the first channels, connecting channels together. The plurality of second channels is defined in part by external walls of the plurality of first channels and the plurality of external fins.

Abstract: A heat exchanger having: an inlet header having inlet tubes stacked against the first side of the heat exchanger; an outlet header having outlet tubes stacked against the second side of the heat exchanger, first inlet and outlet tubes have a same length as each other, second inlet and outlet tubes have the same length as each other and are longer than the first inlet and outlet tubes, and third inlet and outlet tubes have a same length as each other and are longer than the second inlet and outlet tubes; core channels extend from the first side to the second side of the heat exchanger, the core channels connect the inlet tubes to the outlet tubes such that: the first inlet tube and third outlet tube are connected; the second inlet tube and second outlet tube are connected; and the third inlet tube and first outlet tube are connected.

Abstract: A sports field barrier is disclosed for arresting the flight of a ball moving in one direction over a field of play and for rebounding the ball in another direction generally and usually reciprocal to the one direction and with the barrier being erected uprightly along a zigzag course adjacent the field of play. Where the sports field is a tennis court the barrier may be constructed by the steps of intertwining wire coils to form a section of wire mesh fencing, crimping the fencing section or mounting it to forms so as to form the wire coils into a zigzag shape, and mounted the fencing section to a fence frame with the coils stretched between a pair of upright stanchions.