| 摘要 |
1,233,246. Valves. HONEYWELL Ltd. 29 Oct., 1969 [30 Oct., 1968], No. 51401/68. Heading F2V. A gas valve having an inlet port 102, outlet port 104, a closure element 130 mounted on a first tilt lever 140, a second tilt lever 150 normally constrained to move with the first lever, a first control member 120 manually operable to tilt the second lever 150 to open the inlet port 102, an actuator 155 coupled to the second lever and energizable so as to hold the second lever 150 in the open position, and a second control member 123 manually operable to remove the constraint of the first lever 140 on the second 150, has an arrangement such that the removal of the constraint while the actuator 155 remains energized causes a spring 168 to move the first lever to close the inlet port 102 leaving the first control member 120 operatively ineffective pending the de-energization of the actuator 155. A pilot gas passage 107 leads to a pilot burner which is ignitable on depression of switch 108. The first lever 140 comprises two arms 141, 143; the second lever 150 comprises two arms 151, 152, both levers being pivotable at 142. The lower end of arm 143 releasably engages a leaf spring 160 at 163, the other end of spring 160 being secured to the second lever 150 thus forming the constraint for the first and second levers. The arm 151 is secured to a plunger 154 of the actuator 155, which is a solenoid connected to a thermocouple associated with the pilot burner. When the button 114 is depressed a closure element 112 effects a dual closure on the inlet 102 and the first control rod 121 is moved downward. Further movement causes the lower end of rod 121 to rotate arm 152 and hence by constraint also rotate arm 141, so opening the lower part of the inlet 102 to admit gas to the pilot jet. Further depression causes flange 119 to operate the ignition switch 108. The solenoid then holds the closure 130 open and release of the button 114 opens the closure 112 to admit gas to the main jet. Depression of button 124 causes the lower end of the second control rod 123 to contact the end of the leaf spring 160 and break off the constraint (Fig. 4). The spring 168 urges the first lever 140 to the closed position. Whilst, however, the actuator is still energized due to the thermal inertia of the thermocouple, depression of button 114 will not cause the closure 130 to open. The leaf spring 160 may be formed as a bi-metallic strip which deforms under excessive heat to allow the closure 130 to re-seat. |
