An early automatic temperature control for commercial refrigeration\\r\\napplications, employing a \u201csilver dollar\u201d style hydraulic power element, capillary tube sensor and bulb with liquid tight dealing gland; line-voltage, four pole open contact switch, mounted in heavy two-piece, screw assembled, cast enclosure with rubber sealing gasket, Tag Snapon, Circa 1928<\/p>\n\n\n\n
One of a set of two controllers, demonstrating variations in design, engineering and application by the manufacturer, as well as the various effects of natural ageing in use, disuse, abuse and abandonment.<\/p>\n\n\n\n
Features:<\/strong> Technical Significance:<\/strong> 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 \u2013 although current and HP ratings are not shown<\/p>\n\n\n\n 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.<\/p>\n\n\n\n Industrial Significance:<\/strong> An early automatic temperature control for commercial refrigeration\\r\\napplications, employing a \u201csilver dollar\u201d style hydraulic power element, capillary tube sensor and bulb with liquid tight dealing gland; line-voltage, four pole open contact switch, mounted in heavy two-piece, screw assembled, cast enclosure with rubber sealing gasket, Tag Snapon, Circa 1928<\/p>","protected":false},"author":1,"featured_media":20791,"comment_status":"closed","ping_status":"closed","template":"","cpt_portfolio_group":[97,199],"class_list":["post-20790","cpt_portfolio","type-cpt_portfolio","status-publish","has-post-thumbnail","hentry","cpt_portfolio_group-commercial","cpt_portfolio_group-refrigeration"],"yoast_head":"\n
Brass, screw threaded, water tight sealing gland allowing immersion of temperature sensing bulb in liquid bath; \u201cSilver dollar\u201d style hydraulic power element; Cast enclosure overcoated with black paint<\/p>\n\n\n\n
Representative of one of the broad range of approaches to the engineering, design and construction of temperature controllers being experimented with by \u201cme too manufactures\u201d. It was a period of rapid growth in what appeared to be an expanding, economically attractive market place<\/p>\n\n\n\n
See above<\/p>","protected":false},"excerpt":{"rendered":"