GB125650A - Improvements in or relating to Steam-jet Air Ejectors. - Google Patents

Abstract

125,650. Weir, C. & J., and Lang, C. R. Oct. 7, 1916. Aspirating-apparatus, ejector; starting and stopping, automatic.-Relates to the prevention, in steam-jet air ejectors extracting air from condensers and other chambers having a pressure of one-eighth of an atmosphere or less, of the fluctuation in pressure which frequently obtains, and to automatic starting when the ejector has ceased work from this cause. For this purpose the suction chamber surrounding the steam-jet nozzle, or each suction chamber of a multiple ejector, is constructed of as small capacity as possible, and access of air thereto from the vessel to be evacuated is controlled by means of a light plate stabilizing-valve. Fig. 1 shows a single-unit ejector with steam nozzle b, suction chamber a, discharge cone or diffuser nozzle c, and normally-open gravity, plate valve d mounted below the air-suction opening e. When the stream in the diffuser nozzle breaks and blows back, pressure rises in the air suction chamber and the valve closes, remaining in that position until a pressure of about oneseventh of the discharge pressure is reached, whereupon the ejector re-starts, the cycle of action having lasted a fraction of a second. Fig. 4 shows in section part of an arrangement of four ejectors in parallel, the casting of the body having a web s for separating the common steam-chest n and air-chamber m. In each of the four suction chambers a are situated a steam nozzle b with hand stop-valve w, and a gravity plate-valve d controlling, as before, the passage e from the air chamber m. In modifications the plate-valves are arranged for horizontal movement, or they may, while retained on the ejector side of the seat, be adapted to open upwards and be kept normally from closing by means of a light spring. Reference has been directed by the Comptroller to Specifications 3908/77, 541/85, 11818/85, 5325/08, 5334/08, 7294/09, 6284/10, 805/13, and 6758/13.