| 摘要 |
<p>1474758 Reciprocating pumps DANFOSS AS 9 Aug 1974 [21 Aug 1973] 35222/74 Heading F1A [Also in Divisions F2 and F4] A fuel oil supply system for a burner 37 comprises an electromagnetically-actuated pump 1 with a piston 8 connected to an armature 6 and biased into a median position by springs 9, 10, a winding 2 being supplied from an A.C. source 5 via halfwave rectifier 4. The pump delivers via line 15 to a throttle valve 19 controlled by a diaphragm 22 subjected to the delivery pressure and biased to open valve 19 by a spring 25 adjustable by knob 26 to set the delivery pressure, the action of springs 9 and 10 automatically adjusting the piston stroke. A diaphragm accumulator 39 absorbs half the pump output during the delivery stroke and releases it during the following suction stroke. The chamber 44 beneath the accumulator diaphragm and the pump chamber 17 draw fuel from the suction line during the pump suction and discharge strokes respectively, and return the fuel to the suction line during the following stroke, to prevent pulsing in the suction line. A valve 29 prevents delivery of fuel to burner 37 until the pump output pressure is sufficient to depress accumulator diaphragm 39 sufficiently to operate snap-action link 32 and lever 31 to open valve 29, the valve returning to its closed position when the pump output pressure falls below a predetermined level.</p> |
