| 摘要 |
A self-priming centrifugal pump with air trap comprises a chamber 7 formed by a partition wall 6, 10 and one end 9 of the pump housing. The impeller 8 is placed in, and the suction pipe 5 of the pump opens into, said chamber 7. The chamber 7 has two outlets 12, 13 designed in such a way that they permit rotation of a liquid ring along the peripheral wall of the pump housing. Incidentally, the pump housing functions as an air bleeding chamber and is connected to the pressure pipe 4. The suction line 5 of the pump is carried inwards around the axle 14 of the impeller, said axle being journalled in the wall of the suction line outside of the pump housing 1. Hereby, risk of ingress of "false air" at the axle gland is eliminated, because a mechanical axle seal with oil bath may be chosen when it is placed free of fluid. In one embodiment, a canal 16 is running from the suction line 5 out to the peripheral wall of the pump housing at a distance, such that the opening with certainty will be covered by the fluid ring at the starting of the pump. Hereby, the suction line 5 is connected to the pressure line 4 when the pump is stopped, and the vacuum in the suction line 5 is equalised, such that there will be liquid in the pump housing with certainty when the pump is stopped. <IMAGE>
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