GB1093277A - Improvements relating to w.c. flushing systems - Google Patents

Abstract

1,093,277. Valve-discharge water-waste-preventers. SHIRES & CO. (LONDON) Ltd. Dec. 7, 1964 [Dec. 6, 1963], No. 48338/63. Heading EIC. In an air pressure W.C. flushing system a large bore flush pipe 16 with a valve 17 therein leads to the pan and is connected to the water supply and to the bottom of a primary air chamber 10, connected at the top thereof to the bottom of a secondary chamber 11 through a restricted passage 15. The volumes of the chambers 10, 11 are so related that at the minimum supply pressure all the air therein will be compressed into the chamber 11, a quantity of water following it. There is an ejector or venturi device 18 where the supply pipe 20 enters the flushing pipe, the flow therefrom inducing a sub-atmospheric pressure in the chambers 10, 11 while the valve 17 is open. Automatic timing means holds the valve 17 open long enough for flushing to occur and keeps it open for a delay period period after the air has ceased to expand and driven water out of the chamber 10. Timing means prevents the valve 17 opening again within a predetermined period after closure. In a modification the air chambers are below the pan top within a pedestal. Instead of being in the same tank the secondary air chamber is separate from the other and is formed as two vessels below it, one on each side, the flush pipe and valve being therebetween, and also the venturi, which is on the mains side of the valve. The secondary chamber may have a valve to allow air entry when flushing is complete and before the valve 17 closes.