Patent GB-1424711-A (GB)
Title: Gaseous flow control devices for burners
IPC: F23Q9/14
Filed: 1973-02-02
Abstract: 1424711 Burner controllers ROBERTSHAW CONTROLS CO 2 Feb 1973 [4 Feb 1972] 5402/73 Heading F4T [Also in Division F2] A burner controller has a casing with a fuel gas inlet 12 and a single gas outlet 14 for connection to a burner 78, the casing including main and auxiliary flow passages for respectively supplying main and auxiliary flows to outlet 14, a thermostatically operated valve 52 controlling said main flow, a manually operable valve 42 for controlling the main and auxiliary flows, the auxiliary flow passage including a portion 74, 142, 166 bypassing valve 52, a flame responsive safety shut-off valve 16 operative to shut off both flows independently of valve 52, and pressure regulation means 108, 110, 144 in said casing for providing regulation of the pressure of the main and auxiliary gas flows to outlet 14. The burner 78 may be of the type disclosed in Specification 1,380,567 and is operative to heat a water heater H at a low rate when valve 52 is closed and at a high rate when valve 52 is opened by a snap-mechanism operated by a rod and tube type thermostat responsive to the heat demand of heater. The valve 16 is operated by a coil 24 energized by a thermocouple such that coil 24 can maintain valve member 18 open but not pull it open, such opening being effected by pressing button 32, which simultaneously closes valve 36, 38 preventing the main flow to valve 42, and only being possible when a rotary knob of plug valve 42 is at a pilot position, in which valve 42 shuts off the main flow but passes the auxiliary flow via an exterior channel in valve 42, a filter 140, pressure regulator 144 and a restriction 168, which may be adjustable and controls back pressure on regulator 144, to outlet 14. An off position of valve 42 shuts off the main and auxiliary flows, and an on position passes the auxiliary flow as above and passes the main flow via channel 104 and valve 108, 110 to chamber 109. The valve 108, 110 is controlled by a main flow pressure regulator comprising a pressure chamber 124 defined between a regulating diaphragm 126, to which valve member 110 is secured, and a balancing diaphragm 114. The underside of diaphragm 114 is subject to the pressure in an inlet chamber 106 of the regulator; the upper side of diaphragm 114 and the underside of diaphragm 126 are subject via ports 120, 122 to the pressure downstream of valve seat 108; and the upper side of diaphragm 126 is acted on by an adjustable spring 126 in a chamber between diaphragm 126 and a cover 134 having a vent 136 to atmosphere. In a modification-Figs. 6, 7 (not shown), both the main and auxiliary flows pass through the same passage in plug valve 42 and through a common regulator 108, 110 having the construction of the main regulator above. In the off and pilot positions of valve 42, a cam (115) thereon acts on a lever (117) to maintain the thermostatically controlled valve 52 closed, the on position of valve 42 allowing valve 52 to be opened and closed under the control of its thermostat. A passage (111), including an adjustable flow restrictor (113), bypassing valve 52 and downstream of regulator valve 108, 110, passes the auxiliary gas flow to outlet 14 in the pilot and on positions of valve 42.