Patent GB-734402-A (GB)
Title: Means for providing a remote indication or/and control in response to a discharge offluid under pressure
Inventor: GIBSON JOHN HENDRY
IPC: G01F23/00
Filed: 1950-05-09
Abstract: 734,402. Indicating and regulating liquid levels. DEWRANCE & CO., Ltd. May 9, 1951 [May 9, 1950], No. 11523/50. Class 123 (1). [Also in Groups XIII and XIX] Means for providing a remote indication or/and control of an abnormal liquid level in a pressure vessel, comprises a valve that is caused to open on the attainment of an abnormal liquid level to permit a discharge of vapour from the vessel to occur, a passage connecting a pressure sensitive means to the path of discharge of the vapour, and pressure limiting means associated with the passage to safeguard the pressure sensitive means which is adapted, on actuation by the discharge of vapour, to afford the desired indication or/and control. The apparatus may comprise a housing 1, Fig. 1, connected near its upper and lower ends by ports 3 to the steam and water spaces respectively of the associated boiler. In the housing 1 are floats and levers so arranged that when the water in the housing 1 rises above a predetermined level, a valve spindle moves downwards and opens a port allowing steam to be supplied to a high-note emitting whistle 21. Similarly when the water in the housing 1 falls below a predetermined level a similar spindle moves downwards and opens a second port allowing steam to be supplied to a low note emitting whistle 97, Fig. 1. A connection 77 extends from each whistle via a pressure limiting means Fig. 5 to pressure sensitive members 109, 111, Figs. 1 and 4. Each pressure sensitive member houses a collapsible bellows 127 that is compressed by the steam, when its associated whistle is blown, in a manner causing a spindle 147 to operate an electric switch 113. Similarly, the pressure sensitive member 111, when its associated whistle 97 is blown, is caused to actuate an electric switch 115. These switches are so arranged that, in Fig. 6, switch 113 normally closes two contacts 165, 167, but on deflection opens the contacts 165, 167 and closes two contacts 169, 171. Similarly, switch 115 normally closes two contacts 221, 223 but on deflection opens contacts 221, 223 and closes contacts 231, 233. The switches 113, 115 are included in a circuit containing three lamp bulbs 253, 255, 257, of which, when the switches 113, 115 are in their normal position, only bulb 255 is caused to glow. This indicates that the water level in the boiler is satisfactory. If switch 113 is actuated to open contacts 165, 167 and close contacts 169, 171 the lamp 255 is extinguished and lamp 253 is illuminated to indicate that the water level in the boiler is abnormally high. If the switch 115 is actuated to open the contacts 221, 223 and close the contacts 231, 233 the switch 113 being in its normal position, then only the lamp 257 is illuminated to indicate that the water level in the boiler is abnormally low. Instead of or in addition to the lamps 253, 255, 257 means may be included for automatically controlling the feed water supply or the fuel supply to the boiler (see Group XIII), and/or recording means. Instead of two whistles, a single whistle only may be employed. The pressure limiting means in Fig. 5 may be a ball valve 195, 197 under the action of a spring 199. Specifications 480,301 and 734,465 are referred to.