GB426219A - Improvements in feed systems for steam power plant - Google Patents

Abstract

426,219. Feed-water regulators. WEIR, Ltd., G. & J., and HILLIER, H., Holm Foundry, Cathcart, Glasgow. Oct. 27, 1933, No. 29846. [Class 135] Relates to a feed circuit supplying water to a steam power plant and employing a makeup and an overflow valve varying the quantity of water in the system in accordance with variations in liquid level. The closed feed system , shown in Fig. 1 includes a condenser 1 from which condensate is withdrawn by an extraction pump 2 connected by a pipe 4 to a feed pump 5 discharging into the boiler 6. The make-up valve 8, which when open admits water from the feedtank 9 to the condenser 1, and the overflow valve 11, connected between the delivery of the extraction pump 2 and the feed tank 9, are controlled by floats (or a single float) in the condenser 1 and connected pumpchamber 27, either valve through a remote relay needle valve such as 14, with an adjustable seat, or through a pilot valve such as 29 which co-operates with a passage in a part moving with the valve. Either or both of the make-up and overflow valves have a tapered needle valve co-operating therewith, in series with the remote float-operated relay valve. A fall of the float 13, by increasing the opening of the valve 15 permits an increase in the flow of water from a pipe 24 to a chamber 20 in which a perforated piston 16 attached to the make-up valve 8 works ; the adjustable fixed needle valve 23 co-operates with the passage through the piston, so that the valve 8 opens gradually. The low level of the float 26 may be arranged slightly above the high level of the float 13 so that only after the make-up valve 8 has been completely closed by rise of the float 13, is the overflow valve 11 opened, gradually, by rise of the float 26. The passage controlled by the pilot valve 29 connects the chamber immediately below the leaky piston 31 of the overflow valve, with the chamber 27 on the suction side of the pump 2. In Fig. 4, (not shown), the make-up and overflow valves are both operated by remote float-controlled relay needle valves and are both provided with fixed needle valves co-operating with passages through their pistons. Fig. 6, (not shown), differs from Fig. 4 in that both relay valves are operated by the same float in the condenser, and the piston of the overflow valve is above the valve member. In Fig. 7, a combined make-up and overflow valve is controlled by a single relay valve 42. The operating water passes by pump discharge pipe 12 and pipe 76 to piston chamber 69, through the passage 68 through the two pistons, which passage is controlled by the fixed needle valve 71, through piston chamber 70 and pipe 72 to chamber 27. A fall of the float 26 allows increased flow through valve 42, decreasing the pressure in piston chamber 70, and opening the make-up ports 64 gradually. On the other hand a rise of the float, by restricting the flow through the valve 42, will increase the pressure in piston chamber 70 and after closing the make-up ports 64 will gradually open the overflow ports 67. Specifications 192,993 and 263,617, [both in Class 135], are referred to.