| 摘要 |
A device for dosing a flowing fluid is disclosed, the device comprising a casing having an inlet and an outlet. Within the casing there is a supply of the additive with which the flowing fluid is to be dosed, the additive being within a bag. The bag is mounted on a plate which has a passage in it. A needle valve controls flow of additive through the passage. When fluid flows from the inlet through the cylindrical gap to the outlet, the head of the valve is urged by the flowing liquid in the direction which opens the passage. This allows additive to flow from the bag under the influence of the external pressure applied thereto as a result of fluid under pressure having entered the liner through an opening in an end wall of the liner. The degree to which the valve can open the passage is controlled by an eccentric cam which is operable by a knob from externally of the casing. A modification is disclosed in which a number of bags can be mounted on a single plate, the plate having a plurality of passages in it and the arrangement being such that the valve associated with any selected one of the passages can be brought into a position in which it is urged by the flowing fluid into the open position. |
