摘要 |
In a method of reducing the gas content of a liquid in which the liquid is propelled, preferably in a closed circuit, by a centrifugal pump (1), an improved degasification capability is achieved by extracting a portion of the liquid from the suction side of the pump blades (5, 18) in the region of the impeller axis, preferably via a passage (20) extending through a hollow drive shaft (21) of the impeller (14), and conducting this portion of the liquid through a liquid stilling zone (55, 56) where fine gas bubbles are separated from the liquid. The degassed liquid is preferably returned to the liquid in the inlet pipe (15) upstream of the pump (1), where it is set in rotation by a helical member (10). The liquid extracted from the pump (1) may be sucked out by means of an auxiliary rotary pump (3), or it may be entrained by injecting a high speed stream through a venturi nozzle (39) housed by the impeller (14) coaxially with the hollow drive shaft ( 21). In this latter case the degassing of the liquid in the stilling zone (55, 56) may be assisted by an atomizer (44). |