Flow reversing device

A flow switch device, comprising:

• a port block having a rectangular cuboid shape and a central cavity, having a cylindrical shape, in the center of the port block, with four inner ports oriented at 90 degree intervals around an interior surface of the central cavity and four outer ports positioned on an outer surface of the port block, with each port of the four inner ports being in fluid communication with the central cavity and a corresponding one of the four outer ports, wherein a first of the outer ports and a second of the outer ports are positioned on a first outer face of the port block, and a third of the outer ports and a fourth of the outer ports are positioned on a second outer face of the port block, the second outer face being opposite to the first outer face;
• and
• a rotating element within the central cavity of the port block, the rotating element forming a seal with the port block and having two fixed flow passages,
• each of the two fixed flow passages having a curved shape and two ends such that when one end of a first fixed flow passage is aligned with a first one of the four inner ports, another end of the first fixed flow passage is aligned with a second one of the four inner ports that is oriented 90 degrees from the first one of the four inner ports, wherein
• the flow switch device forms selectable flow passages between pairs of the four inner ports separated from each other by 90 degrees and blocks flow between pairs of the four inner ports separated from each other by 180 degrees in each of multiple selected positions of the rotating element.