Armstrong type "WS" and "W" heat exchanger are of shell and tube construction designed for instantaneous heating or cooling of water or other liquids. A popular application of the WS heat exchanger is the heating of water with steam for hot water radiation, while the "W" type exchangers are used for heating or cooling various fluids in applications ranging from swimming pools to industrial processes. Construction of these units would depend upon the fluids used in both the shell and the tubes.

Both WS Heat Exchanger and the W Heat Exchanger are available in either 2 or 4 pass construction, the U-bend tubes expanded into a stationary tube sheet. This construction easily allows for expansion and contraction caused by temperature variations. Units can be connected to any steam boiler or system; however, the capacity of the boiler should be sufficient to handle the load imposed by the heat exchanger. In addition, some method of controlling the flow to the exchanger should be provided and installed according to the manufacturer's directions.

The Armstrong U-Tube Heat Exchanger is designed for durability and includes a removable tube bundle as a standard feature. The ‘U’-bend tube design provides a long service life by eliminating the effects of thermal expansion and contraction. It features carbon steel components, 3/4" (19 mm) copper tubes, and a rugged cast iron head. Components are also available in a selection of materials for use in specific applications.