Refrigerant Flow Controls – Household
An early, second generation, compact, spring compensated, adjustable, automatic expansion valve for use on “dry evaporators made by arguably the leader in the technology of the period, Detroit Lubricator, with cast brass body and aluminium overcoat, built-in inlet filter screen, original moisture protection cap in natural rubber, engineered for sulphur dioxide refrigerant, Model 672, Detroit Lubricator, circa 1935.
Adjustment screw capped with original moisture protecting cap in natural rubber. Rubber is preserved in original condition, unusual for the 1930’s, where rubbers deteriorated quickly, especially in contact with oil. The caps were needed to protect the valve-adjusting stem from condensation water dripping of the coiling unit. Condensation would typically re-freeze along the adjustment screw, causing the valve to loose its calibrated setting.
Removable liquid line inlet screen
Technical Significance:
An example of the new generation of compact, more precisely engineered and performing expansion valves emerging early in the 1930’s, used to maintain cooling units [evaporators], in mechanically cooled refrigerators, at the desired refrigerant pressure.
Dramatises the major gains made by the industry over a period of less than 5 years, during a period of feverish research and development using the scant knowledge and experience available to workers in the field at the time, compare ID # 165 to 168
This artifact of history tells the many stories of early adoption of this particular fluid flow technology, the automatic expansion valve. After a brief flurry of excitement over the use of more costly and delicate float operated devices, as a more efficient means of flow control, industry engineers would return to the automatic expansion valve in the early 30’s. But by then the automatic expansion valve would be a smaller and much more precisely calibrated and efficient device. While the automatic expansion valve was less efficient in its effective use of evaporator surface than high and low side float systems [See HHCC Series 3.01 artifacts, ID # 175 and 176 for example], it had the advantage of reliability, maintainability and affordability, as well as serviceability.
Industrial Significance:
The engineering sophistication and advancements in manufacturing, assembly and materials utilization, represented here, in contrast to ID # 165-168 stands as a remarkable industry achievement.