Device for the dosed introduction of liquid additives to a liquid flowing under pressure

摘要

The invention relates to a device for dosed continuous admixing of a liquid (1) (in particular foam compound) to a liquid (2) (in particular fire-fighting water) flowing under pressure. The main possibility of application is in fire-fighting using foam (fire protection). The admixture comprises two sub-objectives: metering the amount of foam compound, and generating a pressure differential between foam compound and the fire-fighting water delivery stream. This is achieved, according to the invention, by part of the hydraulic energy of the liquid (2) flowing under pressure being converted, by means of a motor (preferably a turbine), into rotary-motion mechanical energy and being utilised to drive a driven machine (preferably a pump having piston-pump characteristics) which is able to raise the pressure of the liquid (1) to a pressure higher than that of the liquid (2) and at the same time meters the liquid (1) in accordance with the flow rate of the liquid (2) and the desired admixture rate. The admixture rate is achieved by varying the flow rate of the liquid (1) by means of adjusting the volumetric flow rate of a variable-delivery pump, gearing (transmission) adjustment or throttling of a branch stream.