Refrigerant Flow Controls – Commercial
An early low-side float, liquid refrigerant flow control, in deep draw copper header, with brass float valve assembly mounted on eight bolt brass flange, with heavy galvanised over coat, designed for four-pass fin coil cooling unit; Frigidaire, EB4885, circa 1929.
Technical Significance:
Following earlier experimentation with automatic expansion valves refrigeration engineers next turned to completely flooded systems for increased evaporator efficiency, using a float valve to meter liquid into the low side of the system.
Low side float metering devices, such as this, were widely employed by the industry in the late 1920’s through the 30’s in both household cabinet refrigerators and commercial applications.
Found in walk-in meat and vegetable coolers in food stores and ware-houses across Canada, these cooling units were to become the work-horses of the commercial refrigeration industry from the 1920’s often through to the 1940
With good maintenance these systems would have a remarkable service life, some in operation for 25 to 30 years, often well into the post WW II period, where they would be replaced by smaller more compact, more efficient systems using the new non-noxious fluorinated hydrocarbon refrigerants, e.g., Freon 12
Costly, delicate, requiring regular service, they would be a short lived solution to refrigerant metering, awaiting the development and refinement of the thermostatic expansion valve
The first widely used, so-called low pressure refrigerant, for household and commercial applications in Canada was sulphur dioxide – highly noxious and corrosive. As a result the prevailing practice in the 1920’s and early 30’s was to make evaporators of copper with a heavy coat of galvanizing.
Industrial Significance:
Much of the Canadian commercial refrigeration service industry would cut its teeth on flooded evaporators and liquid level refrigerant metering float controls. A significant service industry grew up dedicated to maintaining flooded evaporators in good working condition; see extracts from Frigidaire and Kelvinator service manuals.