Document N6pgxLQRKxJ0G2Nnvzxr76ag

Hoffman Specialty Co. Specialties The Operation of the Hoffman Differential Loop is peculiar, inasmuch as it absolutely maintains an unvarying water line in the boiler, independent of boiler pressure, that is no matter whether the boiler pressure is 8 oz. or 5 lbs. the water line in the boiler will maintain at a constant level. It also maintains, when the boiler pressure is more than 10 oz. a fixed pressure difference of 10 oz. between the main steam line from the boiler and the main air return line from the radiators. In other words the pressure in the steam main is always 10 oz. ahead of the pressure in the return line when the boiler pressure is above 10 oz. The maintenance of this pres sure difference between the steam main and the return line insures a continuous flow of steam into and through the radiators. It also means that should an out-of service radiator be put into service when the boiler pressure is 1 lb. or over, that this radiator will heat just as quickly under boiler pressure of 1 lb. or over as it will when boiler pressure is maintained at 8 oz. because the pressure at the inlet valve is 10 oz. more than the pressure at the outlet valve. Hoffman Specialty Co. DATA AND LIST PRICES Specialties Angle StyleSize No. 8 Angle..:..... 54" No 8 Straightway 54 No. 8 Offset........ 54 No. 9 Angle.-........ 34 Right or Left Offsets Diameter Valve Port 54" 54" 54" W* Maximum Capacity Square Feet A 200 211 200 211 200 211 600 3* Dimensions B \$2 114 Hi 1A List Price $6.00 6.00 6.00 8.00 Figs. 1 and 2 show application of Nos. 8 and 9 Hoffman Valve for venting Blast Heaters into gravity or vacuum returns: Fig. 3 shows application of No. 9 Hoff man Valye for draining and venting Fig. 2 Fig. 4 shows application of No. 9 Hoff man Valve for dripping steam or cook ing kettles into gravity or vacuum return. 312 Fig. 3 313