| 摘要 |
1347348 Gear pumps DANFOSS AS 16 July 1971 [20 July 1970 26 June 1971] 33470/71 Heading F1F In a fuel pump for an oil burner, comprising internally meshing gears 19, 20, a by-pass pathway for connecting the delivery side 28 of the pump to the low pressure side and comprising passageway 29, tube 30 passage 33 opening 34, recess 31 and passage 44, is closed during pump operation by an electro magnet 37 attracting an armature 32 against a diaphragm 36 thus closing the opening 34 which however opens as soon as the magnet 37 is de-energized so that when the pump is stopped the pressure in the delivery line rapidly drops, ensuring rapid closing of a combined regulating and cut-off valve 3. The pump is preferably driven by an electric motor energized simultaneously with the electro magnet. The armature 32, which may comprise two discs secured together face-to-face to facilitate formation of passage 33, Fig.3 (not shown), is pivoted on the pipe 30 by means of an O-ring 35. A filter 25 is mounted in an inlet chamber 24 and a cover 41 facilitates removal of the electro magnet 37. In another arrangement, Fig.4, the by-pass pathway is closed by a valve member 81 urged against an opening 64 by the free end 80 of a leaf-spring 78 secured to an armature 74 in the form of a lever mounted on a guide spindle 75 to pivot about an edge 74a. When the pump is stopped, armature 74 is freed and the discharge pressure moves member 81 to the left until communication between passage 64 and the low pressure chamber 73 is established. |
