Refrigerating and Air Conditioning Pressure and Temperature Controls – Household
An early, adjustable, hydraulic bellows actuated control, totally enclosed in 1930’s, modern Bakelite housing, senses evaporator surface temperature, Model R, made for Kelvinator, by Ranco, The Automatic Reclosing Circuit Breaker Co. Columbus, Ohio [A.R.C.B. Co], Circa 1931
One of a rare matched set of six Ranco Model R controllers profiling the evolution of this early self-regulating temperature sensing electric motor control device, likely over several years from 1929 through to the early 1930’s. The set profiles: 1) the progressive design modifications made to improve performance, 2) design adaptations made as required for different models and styles of Kelvinator cabinet refrigerators, 3) different approaches to user friendly and convenient manual temperature setting by the householder, 4) the application of different mounts and accessories, 4) something of the expected life expectancy of the technology in use, 5) the often precipitous modes of failure, anticipated by the refrigeration service man of the period, and 6) various stages of physical deterioration, as a result of natural use, misuse and abandonment. See numbers 7.01-3A, B, C, D, E, F. ID # 131 to # 136
Mounting clamp; Rotary temperature adjustment with black Bakelite pointer knob and quadrant drive gear assembly; See Items 7.01-3 B to G for design and application variations involving special features
Technical Significance:
The Model R series thermostat represented a remarkable engineering achievement in 6 or 7 years. A compact design, totally enclosed control, crafted in, then, modern two tone, Bakelite, dielectric material. One third of the size and weight of the Kelvinator E, it was a user friendly, fully adjustable thermostat.
Industrial Significance:
The thermostat also marks the early entrance of the Ranco name into the refrigeration and air conditioning temperature control business, supporting the major equipment manufacturers of the period. The Ranco name would survive for many years as a leader in the HVACR control field.