GB431517A - Improvements in or relating to boiler feed water systems - Google Patents

Abstract

431,517. Preventing incrustation. LYSAGHT, F. DE S., 93, Chancery Lane, London.-(Northern Equipment Co. ; 111, West 11th Street, Erie, Pennsylvania, U.S.A.) Jan. 5, 1934, No. 453. [Class 123 (i)] [See also Group XIII] Variable amounts of condensate and combined amounts of make-up water and a treatment liquid inversely proportional thereto are supplied to a boiler, the supply of treatment liquid being proportional to that of make-up. In one form a storage tank receives condensate, make-up, and treatment liquid, the two latter supplies being regulated by synchronously operated valves actuated proportionately by a common lever controlled by a float in the tank, and the treated water is supplied by a pump through a main and through thermostatically operated feed-water valves to a battery of boilers. In another arrangement to avoid liming up the main when sodium phosphate is used as the treatment chemical a separate tank 51 and supply pipe 54 are provided for the treatment. Condensate and make-up enter a storage tank 52 through pipes 56, 18, the supply of make-up through pipe 23 and of treatment from a tank 25 being proportionately regulated in dependence on a float 27 by valves 22, 24, actuated by a common arm 30. As shown pumps 53, 57 are steam-operated ; an electric motor controlled in accordance with the level in tank 51 may however operate pump 53. Thermostats 65 regulate the feed into the boilers 10 as by means of valves 63 similar to valves 22, 24. In a modification tank 51 is dispensed with by passing the treatment pump steam through valve 24, the treatment passing direct from the supply tank through the pump to the boiler. To ensure a proportionate amount of flow through valves 22, 24 irrespective of variations in inlet or outlet pressures, means for maintaining a constant pressure drop through the valves are provided and may comprise bellows linked to a valve plunger and ducts connecting the bellows with regions on both sides of the valve. Or a constant liquid head may be provided above the valves by the use of elevated make-up and treatment tanks. The Provisional Specification describes a method of supplying the treatment in proportion to the total feedwater by passing condensate together with make-up through pipe 23.