http://www.spenceengineering.com/Spence/Regulators.cfm

Spence continues its “History of Innovation” by continuing to develop and manufacture quality steam specialty and fluid control products and solutions for the HVAC and industrial marketplace. Spence has introduced several innovative, cost-saving products to the HVAC and industrial process markets including the type “J” Series Pneumatic Control Valve (1986), “Nova” NFT Series Variable Orifice Steam Traps – the first “Made In The USA” float steam trap (1992), CDH Series patented thermostatic sanitary steam trap (2001) and the “CoMBo” CME Series – the industry’s first condensate measuring elbow thermostatic steam trap (2006).
Spence Engineering Company is the industry’s leader in the steam equipment regulation field and is an ISO 9001 certified custom manufacturer of steam specialty & fluid control devices. Our sales offices are located throughout the United States, Europe, Asia, Central and South America, and the Middle East.

Since it’s founding in 1926, Spence Engineering Company has engineered for reliability and longevity. It was the lack luster performance and the frequency of maintenance calls for pressure reducing valves of the 1920s that inspired Paulsen Spence to design the Spence Type ED in 10925.