GB855040A - Sealing arrangement - Google Patents

Abstract

855,040. Stuffing-box substitutes. POWER JETS (RESEARCH & DEVELOPMENT) Ltd. Nov. 11, 1958 [Nov. 15, 1957], No. 35635/57. Class 122 (5). A sealing arrangement comprises a rotor 1 and stator 2 separated by a clearance gap 3 and an annular nozzle 9 for discharging a circumferentially-continuous sheet of sealing fluid across the gap so as to prevent the escape therealong of the fluid being sealed. The stator 2 is in the form of a casing 4 having inserts 5, 6 which together define a sealing fluid chamber 7 and the annular nozzle 9. In operation, pressurized sealing fluid, such as air, is fed into the chamber through a passage 8 and is discharged through the nozzle such that it impinges on the surface of the rotor; a gauze 10 is provided in the chamber to improve the fluid distribution before entering the nozzle. The nozzle may be arranged to direct the sealing fluid towards the direction of leakage flow as shown, or perpendicularly thereto. In a modification, an arcuate groove may be formed in the surface of the rotor opposite the nozzle so that the sealing fluid impinging on the rotor follows a scroll-shaped path, thereby increasing the sealing effect. In the modification shown in Fig. 2, the clearance gap between the rotor 1 and the insert 6 is greater than that between the insert 5 and an arcuate shoulder 11 is formed on the rotor so as to prevent turbulance of the sealing fluid impinging thereon. The arrangement may also., be applied to the case wherein the outer member 4 is the rotor and the inner member 1 the stator, and wherein the surfaces to be sealed lie normal or at an angle to the axis of rotation. The nozzle may be provided on the rotor instead of, or in addition to, the one on the stator and more than one nozzle on either member may be provided. Specification 774,503 is referred to.