US 12,129,928 B2
Pneumatic standstill shaft seal
Johannes Wolf, Gelsenkirchen (DE); Guenter Nadolski, Dortmund (DE); Detlev Ulrich Steinmann, Waltrop (DE); Michael Schiller, Bad Krozingen (DE); Oliver Goetz, Castrop-Rauxel (DE); Jonathan Kleiner, Dortmund (DE); and Berthold Vogel, Schwieberdingen (DE)
Assigned to Flowserve Pte. Ltd., Singapore (SG)
Filed by Flowserve Pte. Ltd., Singapore (SG)
Filed on May 12, 2022, as Appl. No. 17/742,851.
Prior Publication US 2023/0366469 A1, Nov. 16, 2023
Int. Cl. F16J 15/38 (2006.01); F16J 15/00 (2006.01)
CPC F16J 15/38 (2013.01) [F16J 15/008 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A standstill seal configured to form a seal with a rotatable shaft so as to prevent leakage of a process fluid past the standstill seal when the shaft is not rotating, the standstill seal comprising:
a flexible band surrounding the shaft, the flexible band comprising a relatively thicker central region from which relatively thinner side regions extend in a longitudinal direction, the central region, in longitudinal cross section, being substantially rectangular, and being symmetric about a centerline thereof extending perpendicular to the longitudinal direction;
a housing configured to house the flexible band;
a pair of cover plates underlying the side regions of the flexible band and configured to prevent the side regions from being deflected past the cover plates, a cover plate gap being provided between the cover plates through which the central region of the flexible band can be extended;
a control fluid inlet configured to provide fluid communication between a source of pressurized control fluid and a rear surface of the central region of the flexible band, the rear surface of the central region of the flexible band being in direct contact with the housing when the pressurized control fluid is not applied to the control fluid inlet;
a controller; and
a sealing surface parallel to the cover plates and extending fully across the cover plate gap at a uniform offset from the cover plates and from the cover plate gap, the sealing surface being either a surface of the shaft or a surface of an intermediate structure that is sealed to the shaft;
the standstill seal being configured, when the controller applies the pressurized control fluid to the control fluid inlet, to press the rear surface of the central region of the flexible band toward the cover plate gap by flexing and distorting the side regions of the flexible band, such that the rear surface of the central region of the flexible band is no longer in direct contact with the housing, thereby extending the central region of the flexible band through the cover plate gap, such that the central region makes contact and forms a seal with the sealing surface substantially across an entire width of the central region, the rectangular shape of the central region being retained without distortion when the central region forms the seal with the sealing surface and the process fluid applies a lateral pressure to the central region;
the standstill seal being configured, when the controller ceases to apply the pressurized control fluid to the flexible band, to withdraw the central region of the flexible band away from the sealing surface, said withdrawing being assisted by the side regions of the flexible band, which are configured to apply a withdrawing force to the central region of the flexible band that tends to withdraw the central region of the flexible band from the sealing surface.