| 摘要 |
<p>491,271. Fluid -pressure servomotorcontrol systems; valves. NORTHERN EQUIPMENT CO. Aug. 25, 1937, No. 23357. Convention date, Sept. 16, 1936. [Class 135] In apparatus for actuating a boiler feedvalve 19, Fig. 2, through a floating lever 23 in accordance with both the boiler water level and the steam flow from the boiler, the steam flow changes are transmitted to the floating lever by a diaphragm or flexible element 28 acted upon by the different pressures at two points in the steam path, say the inlet and outlet headers of the superheater. The changes in water level are transmitted to the floating lever by a rod 22 connected to an inclined thermostatic tube connected to the steam and water spaces of the boiler. The floating lever may actuate a valve controlling the supply of pressure fluid to a piston or diaphragm operating the boiler feed valve, and the flexible element actuated in accordance with the steam flow may consist of a flexible casing 69, Fig. 7, pressed upwards by a spring 70 and connected to a rod 73 which is linked to the floating lever.</p> |
