INVESTIGATION OF LABYRINTH-SCREW AND SCREW SEALS.

In feed pumps slit seals are widely used but their shortcoming is a large amount of leakage. To reduce this pump designers resort to seals such as end seals with floating rings, labyrinth-screw seals, etc. However, the widespread introduction, e. g. , of labyrinth-screw seals as end seals of feed pumps is hindered by the lack of experimental data. The authors determined under actual conditions and with Reynolds numbers Re//u equals (ub/ upsilon ) 3. 10**3-10**4 the dependence of the pressure on the leakages and the experimental coefficients of pressure and of flow rate for labyrinth-screw (multistart thread on the bush and the screw) and screw seals (one-sided multistart thread) with rectangular profile. The parameters of seals are presented. It is shown that the labyrinth-screw seal with Q// L-SCRIPT equals O maintains the maximum pressure gradient equal to approximately 1. 2-1. 3 MPa, with u approximately equals 36 m/sec, and then the coefficient of pressure k//o approximately equals 1. 2-3. The ratio of the depth of the thread of the screw h//s to the pitch t equal to 0. 1 corresponds to the pressure gradient, whereas the ratio of the depth of the thread of the bush h//b//u to the depth of the thread of the screw h//s is 0. 7-1. In the case h//s approximately equals 0. 11 (variant 3) the depth of the thread of the bush h//b//u equals 0. 6h//s.