| 摘要 |
For the purpose of low-loss variation of the output of a positive-displacement pump, the delivery stream is periodically chopped, by means of a two-lipped rotary shutter (13), into two variable portions, of which the one is passed to a load as useful flow and the other is discharged unpressurised as backflow. The rotary shutter (13) has assigned to it two confronting backflow nozzles (7, 7') which it covers and thus closes intermittently. Arranged on each backflow nozzle (7, 7') there is a non-return valve (12, 12') which is directly connected to the supply line for the load. As a result, the delivery stream columns which are to be accelerated or slowed down during the switching phases produced by the rotary shutter (13), are reduced. This results in reduced noise. <IMAGE>
|
