GB1137197A - A shaft seal - Google Patents

Abstract

1,137,197. Shift seal. P. K. S. NORBERG. 22 Nov., 1967, No. 53269/67. Heading F2B. In a seal for a rotary pump shaft 4, comprising a seal housing 1, 2 supplied with sealing liquid under pressure and enclosing two pairs of sealing rings, each pair comprising a non- rotary ring 8, 10 and a rotary ring 9, 11 urged axially into sealing contact with one another by a spring 17 disposed between the two pairs of rings, the rotary sealing rings 9, 11 being sealed to the shaft by elastic rings 20, 21, means are provided for regulating the spring loading and the pressure of the sealing liquid. The rings 8 and 10 are mounted in holders 14 and 15 respectively, the latter forming the inner end of a spring load adjusting sleeve 6 which is screwed into the end wall 5 of the seal housing and can be locked in position by a lock nut 7. The spring 17 compresses the rings 20 and 21 between the shaft 4 and conical surfaces on the rings 9 and 11 through support rings 18 and 19 respectively. Sealing liquid, preferably water, which may also act as a coolant, is passed through the interior 30 of the housing via an inlet 31 and an outlet 32 at a pressure which is controllable by a throttle valve 33 and during normal operation exceeds that of the pumped liquid so that a small amount of sealing liquid leaks passed the sliding surfaces 12, 13 of the rings 8, 9 and 10, 11. To prevent leakage of sealing liquid when the pump is at rest, the axial pressure exerted by the sleeve 6 may be transmitted direct to the rings 8, 9 and 10, 11 by either compressing the spring 17 until its coils abut one another or by-passing the spring by fitting a sleeve between the rings 18 and 19 and/or between the rings 9 and 11.