Refrigeration 'silver dollar' thermostat
C. J. Tagliabue Mfg Co, Brooklyn N. Y.
Tag Snapon Controller
Brass, screw threaded, water tight sealing gland allowing immersion of temperature sensing bulb in liquid bath; "Silver dollar" style hydraulic power element; Cast enclosure overcoated with black paint
Representative of one of the broad range of approaches to the engineering, design and construction of temperature controllers being experimented with by "me too manufactures". It was a period of rapid growth in what appeared to be an expanding, economically attractive market place
The heavy, open style, four pole switching marked the controller as able to handle larger HP applications than the mainstream of tilting mercury bulb controllers of the time - although current and HP ratings are not shown
The unusual attention given here to robust, waterproof [drip proof] construction and other design attributes is symptomatic of the period. It was one in which, in the absence of field-based experience and codified engineering data, manufactures tended, in many ways, to over design. The effects of progressive simplification can be seen in other controllers in the 7.02 series.