US 12,241,552 B2
Turboexpander labyrinth seal
Duane Bergmann, Big Bear Lake, CA (US); John Park, Irvine, CA (US); Asit Singhal, Lake Forest, CA (US); and Geoff Legg, Huntington Beach, CA (US)
Assigned to ACD, LLC, Santa Ana, CA (US)
Filed by ACD, LLC, Santa Ana, CA (US)
Filed on May 8, 2023, as Appl. No. 18/313,824.
Application 18/313,824 is a continuation of application No. 16/725,815, filed on Dec. 23, 2019, granted, now 11,686,390.
Claims priority of provisional application 62/783,536, filed on Dec. 21, 2018.
Prior Publication US 2023/0272856 A1, Aug. 31, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. F16J 15/16 (2006.01); F01D 11/02 (2006.01)
CPC F16J 15/164 (2013.01) [F01D 11/02 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A turboexpander having a labyrinth seal for reducing gas losses around a rotating shaft, comprising:
a rotating shaft defining a longitudinal axis of rotation and having a series of external teeth thereon along first and second axial segments at respective first and second ends of the shaft;
a compressor wheel fixed to the first end of the shaft and an expander wheel fixed to the second end of the shaft;
first and second bearing housings having bearings that support the shaft at the first and second ends of the shaft, respectively, the axial segments each having teeth located between the bearings and respective compressor wheel and expander wheel; and
stationary labyrinth seals surrounding the first and second axial segments, one at the compressor end and one at the expander end, wherein both labyrinth seals include porting that directs low pressure gas to the respective bearing housing which is open to the atmosphere, wherein each labyrinth seal comprises:
i) a sleeve-like runner surrounding and defining an inner lumen in contact with the teeth on the shaft, the runner having a plurality of radial through holes around a circumference of the runner arranged in a plurality of axially-spaced rows and open to the axial segment;
ii) a carrier comprising a plurality of axially stacked annular discs bonded together to define a central through bore within which is received the runner, each disc having inner openings in fluid communication with aligned through holes at a particular axial position in the runner, and wherein one or more discs have grooves formed in one face thereof that form flow channels in that disc and intersect the central through bore to form a set of inner openings in that disc, wherein the sets of openings of the discs extend in series from a first set of inner openings at a high pressure end of the axial segment adjacent the respective compressor wheel or expander wheel to a last set of inner openings at a low pressure end of the axial segment adjacent the bearings, each set of inner openings leading to a flow channel common to that set of inner openings, and each flow channel being ported to a location separate from the other flow channels.