Rotary seal using pressurized gas flow in centrifugal two-phase separator

Abstract

This disclosure provides a non-contacting sealing assembly for a rotary separator device that separates liquid and / or particulates from a gas stream. The rotary separator includes a stationary outer component and a rotatable inner component that is retained within the stationary outer component. An internal passage is defined between the rotatable inner component and the stationary outer component. The sealing assembly includes a perimeter seal that prevents ingress of the liquid and / or particulates into the internal passage and optionally includes a hub seal that prevents ingress of the liquid or particulate into a chamber volume that encloses one or both of a rotatable shaft and a motor. The perimeter seal may include a perimeter sealing passage connected to the internal passage, where a backpressure gas flow is supplied through the perimeter sealing passage to prevent the ingress of the liquid or particulate into the internal passage. The gas flow may be supplied through one or both of a fan and a compressor configured to recirculate separated gas through the internal passage.

Description

ROTARY SEAL USING PRESSURIZED GAS FLOW IN CENTRIFUGAL TWO-PHASE SEPARATORINCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in its entirety and for all purposes.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Some embodiments of this invention were made with United States Government Support under Contract Nos. 80NSSC18P2185 and 80NSSC19C0208 awarded by the National Aeronautics and Space Administration (NASA). The U.S. Government has certain rights in this invention.TECHNICAL FIELD

[0003] This disclosure relates to fluid seals between rotating and stationary components of a machine, and more particularly to rotary fluid seals in centrifugal two-phase separator devices.BACKGROUND

[0004] Humidity and temperature control are integral in many industrial applications. An air stream may include a binary mixture of air and water. Heat exchangers are used in many industrial applications in humidity and temperature control systems to change the temperature of the air stream. Condensing heat exchangers cool the air stream by heat removal for temperature control, also reducing humidity by condensing water out of the stream. For humidity control, some condensing heat exchangers may remove water directly from the air stream and some condensing heat exchangers may remove water using a water separator downstream from the condensing heat exchanger. Often, condensing heat exchangers that remove water directly from the air stream may do so by allowing condensed moisture to flow out of the condensing heat exchanger by gravity.

[0005] While air and water are ubiquitous on earth, air and water are extremely valuable in space and serve as key ingredients to life in space. Cooling air and removing excess moisture may be critical in space applications. That may allow cooled dry air to be circulated for breathing. However, humidity and temperature control may be more challenging in outer space due at least in part to operating in micro-gravity environments.

[0006] By way of an example, the International Space Station (ISS) may include a Common Cabin Air Assembly (CCAA) for humidity and temperature control. The Common Cabin Air Assembly may include a cabin heat exchanger for cooling an air stream, where the air stream may be cooled by circulating cooled water to remove excess heat. Moreover, the cabin heat exchanger may condense moisture in the air stream by using water-cooled fin surfaces over which the moisture condenses. From there, the condensed moisture and air collects into a “slurper,” where the slurper removes the condensed moisture from the air stream. Figure 1A shows a schematic illustration of a Common Cabin Air Assembly 100 including water-cooled fins 102, air fins 104, and a slurper bar (“slurper”) 106. The slurper bar 106 draws air and the condensed moisture through slurper holes 108. The slurper bar 106 takes in a binary mixture of water and air that is then separated by a rotary separator or fan separator (not shown). The rotary separator removes water from the binary mixture so that cooled dry air may be circulated. Figure IB shows a schematic block diagram of a Common Cabin Air Assembly 100 including a slurper 106 and a water separator 110. As shown in Figure IB, air enters the Common Cabin Air Assembly 100 and is cooled by a humidity control heat exchanger (HX) 112, and a binary mixture of air and water is drawn through a slurper 106. Water is removed by a water separator or rotary separator 110 located downstream from the slurper 106.

[0007] Operation of the slurper 106 depends upon a liquid film wetting the heat exchanger 112 and slurper 106, where operation of the slurper 106 requires a hydrophilic surface. However, the presence of siloxanes and / or other chemical contaminants degrade the surface of the heat exchanger 112 and the slurper 106, converting a hydrophilic coating to behave more hydrophobically. This causes slugs of water to pass by the slurper 106 rather than through the slurper 106, thereby reaching places where water is not desired. Chemical degradation of the slurper 106 occurs by surface modification of the hydrophilic surface into a hydrophobic surface via siloxanes and / or other chemical agents, resulting in inadequate performance. Ultimately, the operation of the slurper 106 and the Common Cabin Air Assembly 100 is compromised.SUMMARY

[0008] The systems, methods, and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0009] One innovative aspect of the subject matter described in this disclosure can be implemented in a rotary separator. The rotary separator includes a stationary outer component, and a rotatable inner component retained within the stationary outer component, where an internal sealing passage is defined between the rotatable inner component and the stationary outer component, where the rotary separator is configured to receive a two-phase mixture comprising a gas stream and liquid or particulates at an inlet of the rotary separator and to discharge separatedgas at an outlet of the rotary separator. The rotary separator further includes a pressurized gas driver configured to recirculate the separated gas from the outlet through an internal passage as a backpressure seal gas, where the backpressure seal gas is configured to prevent ingress of liquid or particulates into the internal passage.

[0010] In some implementations, the rotatable inner component further includes a rotatable drum, and a plurality of vanes arranged about the rotatable drum and connected to the rotatable drum at an inner wall of the rotatable drum. In some implementations, the rotary separator further includes a non-contacting perimeter seal configured to prevent ingress of liquid or particulates into a seal cavity between an outer wall of the rotatable drum and the stationary outer component, where the backpressure seal gas is circulated through the seal cavity to the non-contacting perimeter seal. In some implementations, a width of a seal gap of the non-contacting perimeter seal is between about 0.002 inches and about 0.1 inches. In some implementations, a perimeter sealing passage fluidly connects the non-contacting perimeter seal with the seal cavity, where a cross-sectional area of the perimeter sealing passage is greater than a cross-sectional area of a seal gap of the non-contacting perimeter seal. In some implementations, an interface between the perimeter sealing passage and the non-contacting perimeter seal includes sharp convex corners that are 90 degrees, acute, or obtuse. In some implementations, the stationary outer component includes an overhanging protrusion positioned adjacent to the non-contacting perimeter seal and extends downwards from the inlet of the rotary separator, where the overhanging protrusion includes a radially inward side that faces a flow of the two-phase mixture and a radially outward side that faces a flow of the backpressure seal gas that exits from the non-contacting perimeter seal. In some implementations, the radially outward side and the radially inward side of the overhanging protrusion merge at a tip, where the tip forms an opening angle between the radially inward side and the radially outward side that is less than about 40 degrees. In some implementations, the radially inward side is vertical or substantially vertical, and the radially outward side includes a curved surface or substantially curved surface. In some implementations, the rotary separator further includes a central hub that encloses a rotatable shaft and one or more motors in a chamber volume and configured to rotate the rotatable inner component, and a noncontacting hub seal configured to prevent ingress of liquid or particulates into the chamber volume, where the backpressure seal gas is circulated through the chamber volume to the non-contacting hub seal. In some implementations, a hub sealing passage fluidly connects the non-contacting hub seal and the chamber volume, where the hub sealing passage is defined between corresponding surfaces of the rotatable inner component at the central hub and the stationary outer component at the central hub. In some implementations, the pressurized gas driver is configured to circulate the backpressure seal gas to the chamber volume. In some implementations, the backpressure sealgas is routed from the seal cavity to the chamber volume via hollow vanes of a plurality of vanes of the rotatable inner component. In some implementations, the backpressure seal gas is routed from the seal cavity to the chamber volume via hollowed spars that connect from the stationary outer component to the central hub. In some implementations, the non-contacting hub seal is oriented perpendicular to a direction of flow of the two-phase mixture, and the non-contacting perimeter seal is oriented parallel to the direction of flow of the two-phase mixture. In some implementations, the pressurized gas driver includes one or both of a fan and a compressor. In some implementations, the pressurized gas driver is located adjacent to the outlet of the rotary separator. In some implementations, the rotary separator further includes one or more heaters positioned adjacent to the pressurized gas driver to increase static pressure or reduce relative humidity. In some implementations, the rotary separator further includes an external gas driver configured to circulate additional gas flow through the internal passage to further prevent ingress of liquid or particulate into the internal passage.

[0011] Another innovative aspect of the subject matter described in this disclosure can be implemented in a rotary separator. The rotary separator includes a stationary outer component, a rotatable inner component retained within the stationary outer component, where an internal sealing passage is defined between the rotatable inner component and the stationary outer component, where the rotary separator is configured to receive a two-phase mixture including a gas stream and liquid or particulates at an inlet of the rotary separator and to discharge separated gas at an outlet of the rotary separator, and an external gas driver configured to circulate gas through an internal passage as a backpressure seal gas, where the backpressure seal gas is configured to prevent ingress of liquid or particulates into the internal passage.

[0012] In some implementations, the rotatable inner component includes a rotatable drum, and the rotary separator further includes a non-contacting perimeter seal configured to prevent ingress of liquid or particulates into a seal cavity between an outer wall of the rotatable drum and the stationary outer component, where the backpressure seal gas is circulated through the seal cavity to the non-contacting perimeter seal. In some implementations, a width of a seal gap of the noncontacting perimeter seal is between about 0.002 inches and about 0.1 inches. In some implementations, a perimeter sealing passage fluidly connects the non-contacting perimeter seal with the seal cavity, where a cross-sectional area of the perimeter sealing passage is greater than a cross-sectional area of a seal gap of the non-contacting perimeter seal. In some implementations, an interface between the perimeter sealing passage and the non-contacting perimeter seal includes sharp convex comers that are 90 degrees, acute, or obtuse. In some implementations, the stationary outer component includes an overhanging protrusion positioned adjacent to the non-contacting perimeter seal and extends downwards from the inlet of the rotary separator, where theoverhanging protrusion includes a radially inward side that faces a flow of the two-phase mixture and a radially outward side that faces a flow of the backpressure seal gas that exits from the noncontacting perimeter seal. In some implementations, the radially outward side and the radially inward side of the overhanging protrusion merge at a tip, where the tip forms an opening angle between the radially inward side and the radially outward side that is less than about 40 degrees. In some implementations, the radially inward side is vertical or substantially vertical, and the radially outward side includes a curved surface or substantially curved surface. In some implementations, the rotary separator further includes a central hub that encloses a rotatable shaft and one or more motors in a chamber volume and configured to rotate the rotatable inner component, and a non-contacting hub seal configured to prevent ingress of liquid or particulates into the chamber volume, where the backpressure seal gas is circulated through the chamber volume to the non-contacting hub seal. In some implementations, a hub sealing passage fluidly connects the non-contacting hub seal and the chamber volume, where the hub sealing passage is defined between corresponding surfaces of the rotatable inner component at the central hub and the stationary outer component at the central hub. In some implementations, the backpressure seal gas is routed from the seal cavity to the chamber volume via hollowed spars that connect from the stationary outer component to the central hub. In some implementations, the non-contacting hub seal is oriented perpendicular to a direction of flow of the two-phase mixture, and the noncontacting perimeter seal is oriented parallel to the direction of flow of the two-phase mixture. In some implementations, the rotary separator further includes one or more heaters positioned adjacent to the external gas driver to increase static pressure or reduce relative humidity.

[0013] Another innovative aspect of the subject matter described in this disclosure can be implemented in a seal assembly for a rotary separator configured to separate a gas from liquid or particulate, the seal assembly including a stationary housing, a rotatable vane assembly retained within the stationary housing, where the rotatable vane assembly includes a rotatable drum and a plurality of vanes arranged about a central hub and extending radially outwardly from the central hub to an inner wall of the rotatable drum, a perimeter seal configured to prevent ingress of the liquid or particulate into a seal cavity defined between an outer wall of the rotatable drum and the stationary housing, and a hub seal configured to prevent ingress of the liquid or particulate into a chamber volume of the central hub that encloses one or both of a rotatable shaft and a motor.

[0014] In some implementations, the seal assembly further includes a pressurized gas driver configured to circulate a backpressure seal gas through the seal cavity to the perimeter seal via a first gas flow path and circulate the backpressure seal gas from the seal cavity through the chamber volume to the hub seal via a second gas flow path, where the pressurized gas driver comprises one or both of a fan and a compressor. In some implementations, the stationary housing furtherincludes an overhanging protrusion positioned adjacent to the perimeter seal, where the overhanging protrusion includes a radially inward side that faces the central hub and a radially outward side that faces the inner wall of the rotatable drum, where the radially outward side and the radially inward side merge at a drip edge.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A shows a schematic illustration of a Common Cabin Air Assembly including water-cooled fin surfaces and a slurper.

[0016] Figure IB shows a schematic block diagram of a Common Cabin Air Assembly including a slurper and a water separator.

[0017] Figure 2 shows a schematic diagram of a rotary separator showing water separation and air flow through the rotary separator according to some implementations.

[0018] Figure 3A shows a perspective view of a cross-sectional schematic illustration of a housing implemented in a two-phase separator device for separating liquid or particulate from a gas stream according to some implementations.

[0019] Figure 3B shows a bottom perspective view of a schematic illustration of the housing in Figure 3 A according to some implementations.

[0020] Figure 3C shows a side view of a cross-sectional schematic illustration of a motor mounted to a motor plate in the housing in Figure 3 A according to some implementations.

[0021] Figure 3D shows a perspective view of a cross-sectional schematic illustration of a rotatable vane assembly disposed in the housing in Figure 3 A according to some implementations.

[0022] Figure 4A shows a perspective view of a schematic illustration of an example rotary separator according to some implementations.

[0023] Figure 4B shows a perspective view of a cross-sectional schematic illustration of the rotary separator of Figure 4A according to some implementations.

[0024] Figure 5A shows a cross-sectional schematic view of a rotary separator according to some implementations.

[0025] Figure 5B shows the cross-sectional schematic view of the rotary separator of Figure 5A with arrows indicating directions of fluid flow and gas flow according to some implementations.

[0026] Figure 5C shows a perspective view of the rotary separator of Figures 5A-5B according to some implementations.

[0027] Figure 5D shows a perspective cutout view of a perimeter sealing passage between the stationary housing and the rotatable vane assembly of the rotary separator of Figures 5A-5C according to some implementations.

[0028] Figure 5E shows a cross-sectional schematic cutout view of the perimeter sealing passage of Figure 5D for preventing ingress of liquid or particulate according to some implementations.

[0029] Figure 5F shows a perspective view of a rotatable vane assembly and a drive shaft of the rotary separator of Figures 5A-5E according to some implementations.

[0030] Figure 5G shows an isometric view of a stator of a multi-stage compressor according to some implementations.

[0031] Figure 5H shows an isometric view of a rotor of a multi-stage compressor according to some implementations.

[0032] Figure 51 shows a perspective cross-sectional view of the rotary separator of Figures 5 A-5H with arrows indicating directions of pressurized gas flow for a sealing assembly according to some implementations.

[0033] Figure 5J shows a cross-sectional schematic cutout view of a hub sealing passage of the rotary separator of Figures 5A-5I for preventing ingress of liquid or particulate into a central hub according to some implementations.

[0034] Like reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0035] A two-phase separator device separates liquid (e.g., condensate) or particulates from a gas stream. The two-phase separator device may also be referred to as a condensate separator when separating condensate or as a particulate separator when separating particulates. However, it will be understood that reference to a condensate separator may be used interchangeably with a two- phase separator device. In some implementations, the two-phase separator device may also be referred to as a centrifugal two-phase separator, centrifugal separator, rotary separator, or rotary fluid separator. Rotary separators separate solids from fluids, liquids from gases, or gases from liquids.

[0036] In some embodiments, a two-phase separator device receives a binary mixture of gas (e.g., air) and liquid (e.g., water) or solid (e.g., dust), and separates the liquid or solid from the gas with minimal pressure drop and power draw. A gas stream flows through the two-phase separator device along an axial flow path without being redirected in another flow path, an example of which is shown in Figure 2. The two-phase separator device includes a rotatable inner drum through which the gas stream passes through, where the rotatable inner drum is configured to rotate within a stationary housing (e.g., stationary outer drum). A non-contacting sealing assembly uses backpressure gas flow and features exploiting two-phase interface characteristics to preventingress of liquid or solid into internal passages of the two-phase separator device. The internal passages may be defined between the rotatable inner drum and the stationary housing. In some cases, at least a portion of the backpressure gas flow is supplied by recirculated separated gas from the gas stream. It will be understood that while the two-phase separator device may serve to separate liquid or particulates, some implementations of the two-phase separator device may serve to separate liquid only.

[0037] In some implementations, a two-phase separator serves to replace a water separator and a slurper. As shown in Figure IB, the Common Cabin Air Assembly 100 includes: (i) a slurper 106 for drawing a binary mixture of air and water to a water separator 110, and (ii) a water separator 110 that separates air and water by rotary vanes. However, a two-phase separator of the present disclosure replaces both the slurper 106 and the water separator 110, or at least similar components, in the Common Cabin Air Assembly 100. The two-phase separator may be implemented in an assembly located downstream from a heat exchanger (HX) for temperature and humidity control.

[0038] Though certain implementations of the two-phase separator device of the present disclosure are discussed in the context of space applications and / or micro-gravity environments, it will be understood that the two-phase separator device of the present disclosure may be implemented in a variety of applications. This can include but is not limited to terrestrial applications in humidification / dehumidification, evaporative cooling, oil and gas de- liquidification, and other environmental control markets. Further applications include using the two-phase separator device as a combined blower and separator, refrigeration applications, liquidliquid separation, multi-phase separation, electronic cooling, urine distillation, and capture device for suspended matter.

[0039] Though aspects of the present disclosure may be discussed in the context of a water separator for separating water from an air stream, it will be understood that the present disclosure is not limited to such implementations. Rather, it will be understood that the present disclosure generally relates to liquid / condensate separation from a gas stream, or solid / particulate separation from a gas stream, with water separation from an air stream being an example.

[0040] Conventional centrifugal separators may be utilized for inertial separation of liquid and gas through centrifugal action, and specifically for inertial separation of water and air through centrifugal action. A shaft-driven impeller rotates and moves the flow of water and air from a central location to an outer location. By way of an example, inertia may drive the heavier water against a wall for collection, allowing the lighter air to be directed elsewhere. Conventional centrifugal separators for separating water and air receive a high volume fraction of water in the air stream, where at least about 30% of volume flow in a conventional centrifugal separator iswater. In other words, conventional centrifugal separators take in a lot of water loading. Conventional centrifugal separators receive a mixed-phase air flow and redirect it radially outwards. Put another way, in conventional centrifugal separators the flow of water and air is redirected from a radially central location near the axis of rotation to a radially outer location further from the axis of rotation so that a significant portion of the water and air is pushed to the outer location by centrifugal force. This imposes a significant pressure drop on the flow of the air stream through the centrifugal separator.

[0041] In some embodiments, a rotary separator includes a rotatable vane assembly with a rotatable drum and a plurality of vanes. The rotatable drum and the plurality of vanes are mechanically coupled so as to rotate about an axis of rotation in tandem. The plurality of vanes capture or entrain droplets of water without atomizing them. The flow path of the air stream through the rotary separator is directed along an axial direction that is parallel to the axis of rotation. Rather than accelerating or diverting both air and water suspended in the air radially outwards, the rotary separator of the present disclosure captures water droplets through impact with the rotating vanes and accelerates water after it is captured and deposited on the vanes radially outwards while allowing air to flow directly through axially without being redirected outwards. This imposes a negligible pressure drop on the flow of the air stream through the rotary separator.

[0042] Figure 2 shows a schematic diagram of a rotary separator 200 showing water separation and air flow through the rotary separator 200 according to some implementations. The rotary separator 200 may be configured to receive an air stream 202 from a heat exchanger 210 located upstream of the rotary separator 200. The air stream 202 includes a binary mixture of air 212 and water 222. As shown in Figure 2, the rotary separator 200 includes a stationary outer drum 204 and a rotatable inner drum 206 positioned within the stationary outer drum 204. The rotatable inner drum 206 rotates about an axis of rotation 208 parallel to the direction of flow. Vanes capture the water droplets in the air stream as they pass through the rotary separator 200. Features on the vanes are designed to minimize splash and atomization. Features on the vanes then facilitate transport of the captured liquid by way of the centrifugal force from rotation accelerating the liquid radially outwards towards an outer edge of the rotatable inner drum 206 for collection while air 212 continues to pass through the rotary separator 200 along the direction of flow. The air 212 exits the rotary separator 200 providing cooler, dehumidified air, and the water 222 may be collected from an outer edge of the rotatable inner drum 206 in a collection area 224. It will be understood that the schematic diagram of the rotary separator 200 in Figure 2 is intended to be a conceptual illustration of air flow through the rotary separator 200 and water capture by the vanes and transport to the outer edge of the rotatable inner drum 206. Accordingly, the schematicdiagram of the rotary separator 200 in Figure 2 is not intended to be fully illustrative of the mechanical components and operations of the rotary separator 200.

[0043] Generally, a two-phase separator device is configured to separate liquid or particulate from a gas stream. The two-phase separator device may include a stator or static member such as a stationary housing. The two-phase separator device may also include a rotor or rotatable member such as a rotatable vane assembly. The rotatable vane assembly may be retained in the stationary housing, where the rotatable vane assembly includes a plurality of vanes. The plurality of vanes may have features (e.g., grooves) formed therein to capture liquid or particulate. An example centrifugal two-phase separator device is shown in Figures 3A-3D, where different views of a stationary housing of the centrifugal two-phase separator device are shown in Figures 3 A-3C, and a perspective view of the stationary housing and rotatable vane assembly of the centrifugal two- phase separator device is shown in Figure 3D. Additional examples of centrifugal two-phase separator devices are shown in Figures 4A-4B and 5A-5J.

[0044] Figure 3A shows a perspective view of a cross-sectional schematic illustration of a housing 310 implemented in a centrifugal two-phase separator for separating liquid or particulate from a gas stream according to some implementations. The gas stream may flow through the housing 310, entering through an inlet (top) of the housing and exiting through an outlet (bottom) of the housing 310. As used herein, terms such as “under,” “over,” “below,” “above,” “bottom,” “top,” “lower,” and “upper” are relative terms and may be used for ease of describing the figures, and may be used to indicate relative positions to the orientation of the figure on a properly oriented page. In some implementations, terms such as “upper,” “top,” and “front” may refer to positions that are upstream and terms such as “lower,” “bottom,” and “back” may refer to positions that are downstream. The housing 310 includes a physical structure and barrier defining an inner volume through which the gas stream flows through. The housing 310 may surround or otherwise form an outer barrier around a rotatable vane assembly as shown in Figure 3D, where the rotatable vane assembly is retained within the housing 310. As used herein, the housing 310 may also be referred to as a casing, outer barrier, outer frame, outer drum, or drum.

[0045] In some implementations, the housing 310 is cylindrical. In some implementations, the housing 310 may be stationary during operation. As shown in Figure 3 A, the housing 310 may include an outer drum 320, where the outer drum 320 defines an outer wall of the housing 310. An inner drum 330 may be retained in the housing 310. The inner drum 330 may be positioned adjacent to the outer drum 320. In some implementations, the inner drum 330 is configured to rotate whereas the outer drum 320 is configured to remain stationary when the inner drum 330 is rotating. The outer drum 320 may have a passage or groove formed into a top edge for a top bearing 322. A retaining ring 332 is provided in a slot formed in the inner drum 330, where theretaining ring 332 rests on the top bearing 322. That way, the inner drum 330 can rest on the outer drum 320. The outer drum 320 may be part of the housing 310 that is stationary. The inner drum 330 may be part of a rotatable vane assembly or may be configured to rotate with a rotatable vane assembly. A clearance space may exist between the inner drum 330 that freely rotates and the outer drum 320 that is stationary. As discussed below, a non-contacting seal of the present disclosure may prevent ingress of liquid or particulate into the clearance space between the inner drum 330 and the outer drum 320.

[0046] Figure 3B shows a bottom perspective view of a schematic illustration of the centrifugal two-phase separator in Figure 3 A according to some implementations. The outer drum 320 may be mounted to a motor plate 312 at the bottom of the housing 310, and the inner drum 330 may be mounted to a drum plate 314. The drum plate 314 may be positioned above the motor plate 312. As shown in Figures 3 A-3C, a lower bearing 316 is disposed between the drum plate 314 and the motor plate 312, where the drum plate 314 is fitted to the lower bearing 316, and where the lower bearing 316 serves as a stabilization point for the rotating inner drum 330. In some implementations, the outer drum 320, inner drum 330, motor plate 312, and drum plate 314 may include a metallic material such as aluminum or aluminum alloy.

[0047] Figure 3C shows a side view of a cross-sectional schematic illustration of a motor 340 mounted to the motor plate 312 in the centrifugal two-phase separator in Figure 3 A according to some implementations. The motor 340 is mounted to the motor plate 312 and configured to cause rotation of the inner drum 330. In some implementations, a drive shaft 342 connected to the motor 340 may be fitted to a matching slot in the drum plate 314. The electromotive force provided by the motor 340 drives rotation of the drive shaft 342 and the inner drum 330.

[0048] Figure 3D shows a perspective view of a cross-sectional schematic illustration of a rotatable vane assembly 350 disposed in the housing 310 of the centrifugal two-phase separator in Figure 3 A according to some implementations. The housing 310 and the rotatable vane assembly 350 may be part of the centrifugal two-phase separator 300. The rotatable vane assembly 350 includes a rotatable drum 360, where the rotatable vane assembly 350 is attached, mounted, retained, mechanically coupled, or connected to an inner wall 318. An insert wall 364 may attach, mount, retain, mechanically couple, or connect to the inner wall 318, and the insert wall 364 may face inwardly towards a center of the centrifugal two-phase separator 300. The insert wall 364 may be sloped. The rotatable vane assembly 350 includes a plurality of vanes 352 arranged about an axis of rotation that is along the axial direction of the centrifugal two-phase separator 300, where the rotatable drum 360 rotates about the axis of rotation. Each of the plurality of vanes 352 radially extends from the axis of rotation to attach, mechanically couple, or otherwise connect to the rotatable drum 360 at the insert wall 364 of the rotatable drum 360. In some implementations,each of the plurality of vanes 352 may be attached, mechanically coupled, or otherwise connected to a central hub 370 positioned about the axis of rotation. In some implementations, the centrifugal two-phase separator 300 further includes a motor configured to drive rotation of the rotatable drum 360 and / or the plurality of vanes 352 about the axis of rotation. In some implementations, the central hub 370 may enclose or house a motor for driving rotation of the rotatable drum 360 and / or the plurality of vanes 352 about the axis of rotation.

[0049] The motor may provide electromotive force to cause the plurality of vanes 352 to rotate in a clockwise or counterclockwise direction about the axis of rotation. In other words, the motor may transmit torque to a shaft that causes the plurality of vanes 352 to rotate about the axis of rotation. An inner edge of each vane 352 may be connected or attached to the central hub 370 and an outer edge of each vane 352 may be connected or attached to the rotatable drum 360.

[0050] In some implementations, the geometry and number of vanes 352 may be optimized for capturing or entraining liquid or particulate in the gas stream with minimal pressure drop and / or minimal power draw. In some implementations, the geometry of the vanes 352 may have a straight design or a helical design. In some implementations, the geometry of the vanes 352 may be substantially straight with features at the tip and / or tail (i.e., the leading and / or trailing edge) of each vane to improve pressure drop and / or power draw. In some implementations, the inner edge of each vane 352 may have an axial length that is less than an axial length of the outer edge of each vane 352. In some implementations, the axial length of the inner edge may be between about 0.5 inches and about 4 inches, or between about 1 inch and about 3 inches. In some implementations, the axial length of the outer edge may be between about 1.5 inches and about 8 inches, or between about 2 inches and about 6 inches. In some implementations, the axial length of each vane 352 may taper from the outer edge to the inner edge. In some implementations, the plurality of vanes 352 may include between about two and ten vanes, such as about two, three, four, five, six, or seven vanes.

[0051] Each of the vanes 352 may have major surfaces and minor surfaces, where major surfaces occupy significantly greater surface area than minor surfaces of each vane 352. In some implementations, the major surfaces are defined by the axial length and a radial length of the vanes 352, and the minor surfaces are defined by a lateral width and the radial length of the vanes 352. Generally speaking, the major surfaces of the vanes 352 make impact with droplets of liquid or particulate in a gas stream as the plurality of vanes 352 are rotated.

[0052] A plurality of features 354 may be formed or otherwise defined in at least one of the major surfaces of each of the plurality of vanes 352. Such features 354 may serve to promote capture of the liquid (e.g., condensate) with minimal splashing or atomizing of the liquid. As used herein, the features 354 defined in a major surface of each vane 352 may also be referred to astrenches, divots, slots, inserts, channels, grooves, indentations, and the like. Generally, the plurality of features 354 are non-planar features defined in the vanes 352 that arrest the liquid without atomizing, and that provide a pathway for the liquid to be drained away after being arrested. In some implementations, the plurality of features 354 may extend radially from the inner edge of the vane 352 to the outer edge of the vane 352. For example, the plurality of features 354 may be arranged as rows of grooves. The rows of grooves may span across the radial length of each of the vanes 352. In some implementations, the plurality of features 354 may have a spiral shape. In some implementations, the plurality of features 354 may have a zig zag shape. In some implementations, the plurality of features 354 may be a defined as a series of divots for capturing the liquid, where the series of divots may transport the liquid to a porous substrate.

[0053] In some implementations, the features 354 may be sloped from the inner edge to the outer edge of each vane 352 to promote upward motion of captured droplets of liquid along the radial length of the vane 352. For example, as each of the vanes 352 may be tapered from the outer edge to the inner edge, the features 354 of a particular vane 352 may be parallel or substantially parallel to each other as well as to a top slope of the particular vane 352. Captured liquid accelerates radially outwardly towards the outer edge and in an upward direction against the flow path of the gas stream. The upward direction may be against the gravity vector in the centrifugal two-phase separator 300. The captured liquid accelerates radially outwardly and in an upward direction by centrifugal force during rotation of the plurality of vanes 352.

[0054] The rotational velocity of the plurality of vanes 352 provides sufficient centrifugal force to accelerate the captured liquid to be drained away towards a pickup device. Furthermore, the captured liquid is accelerated radially outwardly and in an upward / upstream direction along the inner wall 364 of the rotatable drum 360. The inner wall 364 of the rotatable drum 360 is sloped to promote acceleration of the captured liquid or particulate in an upward / upstream direction to an upstream lip 366 of the rotatable drum 360. An upstream lip 366 is positioned towards the inlet of the housing 310 and a downstream lip 368 is positioned towards the outlet of the housing 310. The sloped inner wall 364 provides a taper from a downstream lip 368 to the upstream lip 366 of the rotatable drum 360. Put another way, the inner wall 364 of the rotatable drum 360 may be sloped at an acute angle with respect to horizontal plane. This facilitates acceleration of captured liquid radially outwardly from the features 354 of a vane 352 along a sloped inner wall 364 to an upstream lip 366 of a rotatable drum 360 where the captured liquid can be collected. The upstream lip 366 at a terminal end of the inner wall 364 may include curved surfaces to form a channel that facilitates capture and collection of liquid.

[0055] As the captured liquid is accelerated radially outwardly and towards the upstream lip 366 of the rotatable drum 360, the captured liquid may accumulate at a location on the upstreamlip 366 of the rotatable drum 360 or adjacent to the upstream lip 366 of the rotatable drum 360. In some implementations, the captured liquid may form a ring of liquid at the upstream lip 366 or adjacent to the upstream lip 366 of the rotatable drum 360. In some implementations, a channel 380 is formed or defined in the rotatable drum 360 in a location adjacent to the upstream lip 366 of the rotatable drum 360. The ring of liquid may accumulate in the channel 380. As used herein, the channel 380 may also be referred to as a slot, trench, feature, indentation, groove, or pitot groove. The channel 380 and the sloped inner wall 364 of the rotatable drum 360 provide a volume for the transient storage of captured liquid as the rotatable drum 360 rotates.

[0056] In some implementations, the captured liquid may be accelerated radially outwardly to a channel 380 formed in the rotatable drum 360, such as the inner wall 318 of the rotatable drum 360, that is adjacent to the upstream lip 366 of the rotatable drum 360. Where the channel 380 is formed in the inner wall 318, it will be understood that the inner wall 318 rotates with the rotatable drum 360 and the outer wall 328 of the housing 310 remains stationary. Such a channel 380 is shown in Figure 3D. The captured liquid may be accelerated radially outwardly to the channel 380 formed in the rotatable drum 360 that is adjacent to the upstream lip 366 of the rotatable drum 360.

[0057] Captured liquid at the upstream lip 366 of the rotatable drum 360 and / or in the channel 380 adjacent to the upstream lip 366 of the rotatable drum 360 may be collected by a collecting device (not shown) such as a pitot pump or tube. It will be understood that any pickup tube or pickup device can be used in place of the pitot pump or tube. Examples of a pitot pump positioned in a channel 380 adjacent to an upstream lip 366 of a rotatable drum 360 are shown in Figures 4A- 4B. The pitot pump may be disposed above the upstream lip 366 of the rotatable drum 360 for receiving and collecting the captured liquid, where the captured liquid can be moved by stagnation pressure. In some implementations, the pitot pump may be disposed above the upstream lip 366 of the rotatable drum 360 and at least partially within the channel 380 adjacent to the upstream lip 366, where the channel 380 is defined in the housing 310 or defined in the rotatable drum 360.

[0058] The pitot pump may be stationary during operation of the centrifugal two-phase separator 300. Specifically, the pitot pump is stationary while the rotatable drum 360 is rotating. When the captured liquid is accumulated at the upstream lip 366 or in the channel 380, the pitot pump is configured to receive captured liquid as the captured liquid rotates with the rotatable drum 360. The rotational velocity of the captured liquid impinges the pitot pump so that the pitot pump receives the captured liquid. Sufficient pressure is created to force the captured liquid out of the upstream lip 366 or channel 380 and into the pitot pump. From there, the captured liquid is collected by the pitot pump.

[0059] As the pitot pump collects captured liquid, sufficient stagnation pressure is developed in the pitot pump to move the captured liquid to a collection system. In some implementations, the collection system is a collection basin. The collected liquid may be processed by a water processing unit or water processing assembly positioned downstream from the centrifugal two- phase separator device 300. The water processing assembly may be configured to treat the liquid. For example, the water processing assembly may be configured to convert contaminated water into potable water.

[0060] As the centrifugal two-phase separator 300 captures or collects liquid from the two- phase mixture, the gas stream from the two-phase mixture passes through the centrifugal two- phase separator 300. As discussed below, at least some of the gas stream is recirculated as backpressure gas flow to form a non-contacting seal that prevents ingress of liquid into internal passages between the rotatable drum 360 and the stationary housing 310 of the centrifugal two- phase separator 300.

[0061] The centrifugal two-phase separator device of the present disclosure may be able to achieve removal of a significant amount of condensate or particulate from a gas stream with minimal power draw and minimal pressure drop. The centrifugal two-phase separator device may capture condensate without atomizing or dispersing the condensate. The captured condensate or particulate may be accelerated radially outwardly and in a motion against the flow of the gas stream by centrifugal force. The centrifugal two-phase separator device may be able to operate in micro-gravity conditions, meaning that the centrifugal two-phase separator device can effectively separate condensate from gas or separate particulate from gas even in micro-gravity conditions. The centrifugal two-phase separator device may be compact and occupy a low volume.

[0062] Figure 4A shows a perspective view of a schematic illustration of an example rotary separator 400 according to some implementations. Figure 4B shows a perspective view of a cross- sectional schematic illustration of the rotary separator 400 of Figure 4A according to some implementations. The rotary separator 400 may include a casing or housing 410, where a rotatable vane assembly 450 is retained within the housing 410. The rotatable vane assembly 450 includes a rotatable drum 460 configured to rotate about an axis of rotation along an axial direction of the rotary separator 400. A gas stream flows through the rotary separator 400 in the axial direction. The rotatable vane assembly 450 further includes a plurality of vanes 452 arranged about the axis of rotation or rotatable shaft. In some implementations, the rotatable vane assembly 450 further includes a central hub 470 centered about the axis of rotation. The plurality of vanes 452 radially extend from the central hub 470 and connect to the rotatable drum 460. Each vane 452 is connected to the rotatable drum 460 at an outer edge of the vane 452 and connected to the central hub 470 at an inner edge of the vane 452. As shown in Figure 4A, the plurality of vanes 452 maybe at least five vanes each having a straight or flat-facing geometry. As shown in Figure 4B, the central hub 470 may enclose a motor 440 for driving rotation of the rotatable vane assembly 450.

[0063] A plurality of grooves 454 may be defined on at least one of the major surfaces of the plurality of vanes 452, where the plurality of grooves 454 extend radially outwardly along a radial length of each vane 452. The plurality of grooves 454 may be arranged as rows of grooves 454 across the major surface of the vane 452. The plurality of grooves 454 capture droplets of liquid during rotation of the rotatable vane assembly 450 through impact and minimize atomization and splash from droplet impact. The plurality of grooves 454 also facilitates transport of the captured liquid radially outwards towards the rotatable drum 460 while shielding it from direct exposure to shear by the air stream.

[0064] The plurality of vanes 452 connect to the rotatable drum 460 at an insert wall 464 of the rotatable drum 460. The rotatable drum 460 may be configured to rotate about the housing 410 during operation, which may be stationary. The inner wall 464 may be sloped towards an upstream lip 466 of the rotatable drum 460. A channel 480, such as a ring-shaped channel in the rotatable drum 460, is defined adjacent to and above the upstream lip 466 of rotatable drum 460. The rotary separator 400 further includes a pitot pump 490, where the pitot pump 490 is disposed above the upstream lip 466 and has an opening at least partially within the channel 480 of the rotatable drum 460. The pitot pump 490 may collect liquid accelerated radially outwardly into the channel 480 from the vanes 452.Non-Contacting Rotary Seal

[0065] A two-phase separator device or condensate separator may be a rotary separator. Rotary separators for separating solids from fluids or liquids from gases typically include a rotatable tubular body (e.g., “drum”) having a bore with inlet and outlet ends. Fluid flow enters the inlet end and passes through the bore such that liquids / condensate are directed outwardly for separation while gas passes through the outlet end. The rotary separator also includes a stationary housing or static member, where the stationary housing is located adjacent to the drum. For example, the stationary housing may be a partition wall or casing. The drum may be positioned within the stationary housing. To prevent leakage of fluids from the drum to the stationary housing, seals are necessary between rotating and stationary components. These seals are necessary to prevent liquid or liquid-gas mixtures from exiting or bypassing a catchment area or separating chamber of the rotary separator. Leaked fluids that bypass the catchment area or separating chamber will reduce the efficiency and performance of the rotary separator. Moreover, these seals are necessary to keep the fluids away from bearings, mechanical drivers, and electrical motors of the rotary separator.

[0066] Mechanical seals are often applied to prevent intrusion of fluids or solids. Such mechanical seals may be contacting seals. Examples of mechanical seals include lip seals, coatings, o-rings, and the like. However, mechanical seals positioned between stationary and rotating components add friction. Increased friction leads to increased drag, thereby resulting in an increased power draw. Further, mechanical seals may cause contamination due to abrasion. Moreover, mechanical seals may wear down over time and require replacement. Thus, mechanical seals require high power consumption, require additional cooling, require additional cost, result in a higher likelihood of contamination, and require replacement over time.

[0067] Rather than placing contacting / mechanical seals between stationary and rotating parts in a rotary separator, non-contacting seals may be implemented. As there is some clearance between the stationary and rotating part, the seal between the stationary and rotating part is noncontacting. Typically, non-contacting seals are labyrinth seals that impede the leakage of fluid between rotating and stationary parts. Labyrinth seals generally provide a tortuous path to prevent leakage, where the labyrinth seal may be composed of multiple grooves or “teeth” on a rotating shaft. Many gas turbines, having high rotational speeds, use labyrinth seals because of their lack of friction. Other non-contacting seals may include hydrodynamic seals and magnetic seals. However, labyrinth seals require very tight clearances, may be expensive to engineer, may incur drag, and do not prevent against capillary forces that are stronger in micro-gravity. Where the rotary separator operates in micro-gravity, labyrinth seals may be ineffective.

[0068] The present disclosure relates to a non-contacting seal in a two-phase separator device or rotary separator. Specifically, the non-contacting seal is a backpressure seal that utilizes recirculated gas or air to push back against fluid in an internal passage between stationary and rotating components. Gas flow in the backpressure seal may come from recirculated gas that is generated using a pressurized gas driver (e.g., pump, fan, compressor, etc.) that recirculates a portion of separated gas flow. Additionally or alternatively, gas flow in the backpressure seal may come from gas that is originated externally, where the gas may be dry gas or air coming from an external pump or fan located outside of the rotary separator. In some implementations, one or more non-contacting seals in the rotary separator includes a perimeter seal configured to prevent ingress of liquid or solid into a cavity between an outer wall of a rotatable body and a stationary housing. In some implementations, the one or more non-contacting seals in the two-phase separator device includes a central seal (or hub seal) configured to prevent ingress of the liquid or solid into a chamber volume that houses one or both of a rotatable shaft and a motor. Seal gaps or seal passages leading to the cavity or chamber volume are designed in a manner to prevent intrusion of liquid. Specifically, the seal gaps and seal passages are oriented, shaped, dimensioned, and incorporated with features to promote high-velocity gas flow to push back fluid and to preventintrusion of liquid by capillary forces and dynamic momentum. In some instances, the seal gaps and seal passages are narrow and have sharp convex corners to limit ingress of liquid. In some cases, a drip edge or overhanging protrusion is placed adjacent to a seal opening that is designed to prevent a main process stream from interacting with liquid in a pitot groove, redirects any spray / splash towards the plurality of vanes or rotatable shaft, and prevents spray / splash from entering the seal opening.

[0069] The non-contacting seal of the present disclosure is not limited to rotary separators disclosed in Figures 2, 3A-3D, 4A-4B, and 5A-5J. The rotary separators in Figures 2, 3A-3D, 4A-4B, and 5 A-5 J are intended to be illustrative examples. In fact, the non-contacting seal of the present disclosure may be applied to any rotary separator or two-phase separator device that separates liquid (e.g., condensate) or solid (e.g., particulate) from a gas stream. For instance, other potential applications of the present disclosure include urine processor rotary vapor compression distillation or dust / particle separation.

[0070] Figures 5A-5J show various views, cross-sections, and cut-outs of a rotary separator according to some implementations of the present disclosure. A rotary separator 500 shown in Figures 5 A-5 J may be configured to receive a binary mixture comprising a gas stream and a liquid. In some instances, the rotary separator shown in Figures 5A-5J is configured to receive a binary mixture comprising a gas stream and particulate(s). The rotary separator 500 has non-contacting seals between corresponding surfaces of rotatable and stationary parts, where a backpressure seal gas is circulated through the non-contacting seals to limit ingress of liquid or particulate. The backpressure seal gas may be taken from at least a portion of separated gas processed by the rotary separator 500. A sealing assembly of the rotary separator 500 may be said to comprise the noncontacting seals of the present disclosure.

[0071] Figure 5A shows a cross-sectional schematic view of the rotary separator according to some implementations. The rotary separator 500 includes a rotatable inner component such as a rotatable vane assembly 510 and a stationary outer component such as a stationary housing 520. The rotatable inner component may be retained by the stationary outer component. The stationary housing 520 defines a bore 522 through which a binary or two-phase mixture flows through. The binary mixture may also be referred to as a main process stream. The binary mixture may enter through an inlet 524 of the rotary separator 500 and exit an outlet 528 of the rotary separator 500. The rotatable vane assembly 510 may be within, enclosed by, or surrounded by the stationary housing 520. The rotatable vane assembly 510 may include a rotatable drum 512 that rotates about an axis of rotation, a central hub 514 that is centered along the axis of rotation, and a plurality of vanes 516 that are connected to the rotatable drum 512 and the central hub 514. The plurality of vanes 516 are arranged about the rotatable drum 512 and connected to the rotatable drum 512 atan inner wall of the rotatable drum 512. A seal cavity 530 is defined as a space between an outer wall of the rotatable drum 512 and the stationary housing 520. A chamber volume 540 is defined as a space enclosed by the central hub 514. The central hub 514 may enclose one or both of a rotatable shaft 542 and a motor 544. A perimeter seal 550 is a non-contacting seal that includes one or more openings that fluidly connect the bore 522 and the seal cavity 530. The perimeter seal 550 may also be referred to as a first seal or first non-contacting seal. A hub seal 560 is a non-contacting seal that includes one or more openings that fluidly connect the bore 522 and the chamber volume 540 enclosed by the central hub 514. The hub seal 560 may also be referred to as a second seal or second non-contacting seal. Non-contacting seals are located at the perimeter seal 550 and the hub seal 560 to prevent ingress of liquid / particulate from entering the seal cavity 530 and the chamber volume 540, respectively.

[0072] Figure 5B shows the cross-sectional schematic view of the rotary separator of Figure 5A with arrows indicating directions of fluid flow and gas flow according to some implementations. A binary mixture comprising a gas stream and a liquid or particulate flows through the bore 522 of the stationary housing 520. The rotary separator 500 includes the inlet 524 for receiving the binary mixture and the outlet 528 for discharging a separated gas stream. As the binary mixture passes through the bore 522, the rotatable vane assembly 510 in the stationary housing 520 separates the liquid or particulate from the gas stream. The liquid or particulate is directed radially outwardly towards the inner wall of the rotatable drum 512. The liquid or particulate travels along the inner wall of the rotatable drum 512 to a pitot groove 518 by centrifugal force. In some implementations, the liquid or particulate in the pitot groove 518 may be collected by a pitot tube or pickup tube 554 for extraction from the two-phase mixture. As the liquid or particulate is separated from the gas stream by the rotatable vane assembly 510, the gas stream continues to flow through the bore 522 towards the outlet 528. In some implementations, the separated gas stream exits the rotary separator 500 at the outlet 528.

[0073] In some implementations, a portion of the separated gas stream recirculates as backpressure seal gas through internal seal passages. The backpressure seal gas is represented by dashed arrows in Figure 5B. The backpressure seal gas flows through internal seal passages of the rotary separator 500. The internal seal passages may include the seal cavity 530, a perimeter seal passage 552 connecting the seal cavity 530 and the perimeter seal 550, and the perimeter seal 550 itself. In some cases, the internal seal passages may further include the chamber volume 540, a hub seal passage 562 connecting the chamber volume 540 and the hub seal 560, and the hub seal 560 itself. A fan, a compressor, or a combination thereof may be integrated with the rotatable vane assembly 510 and / or the stationary housing 520 to recirculate, pressurize, or drive a portion of the separated gas stream through the internal seal passages. This includes the seal cavity 530,the perimeter seal passage 552, and the perimeter seal 550, and may optionally include the chamber volume 540, the hub seal passage 562, and the hub seal 560.

[0074] The fan, the compressor, or the combination thereof supplies pressurized gas flow to the perimeter seal 550 between the rotating component (i.e., rotatable drum 512) and the stationary component (i.e., stationary housing 520), thereby preventing stagnant moist air in the voids between the rotating component and the stationary component, which minimizes condensation. In addition or in the alternative, the fan, the compressor, or the combination thereof may recirculate, pressurize, or drive a portion of the separated gas stream through hollow vanes of the plurality of vanes 516 to the central hub 514 so that the separated gas stream flows through the chamber volume 540, the hub sealing passage 562, and the hub seal 560. This allows pressurized gas flow to the hub seal 560, providing pressurized gas flow and convective cooling to the rotatable shaft 542, motor 544, bearing(s), and other components in the central hub 514. This further prevents stagnant moist air to avoid condensation in the hub near the bearings or motors.

[0075] Figure 5C shows a perspective view of the rotary separator of Figures 5A-5B according to some implementations. The rotary separator 500 includes the stationary housing 520 and the rotatable vane assembly 510. The stationary housing 520 may house, enclose, surround, contain, or provide static casing about the rotatable vane assembly 510. The rotatable vane assembly 510 includes a rotatable drum 512 configured to rotate within the bore 522 of the rotary separator 500. The stationary housing 520 may include a top plate 532 located at the inlet 524 of the rotary separator 500 and may include a bottom plate 534 located at the outlet 528 of the rotary separator 500. The top plate 532 may include static arms or spars that extend from the walls of the stationary housing 520 to the central hub 514. A person having ordinary skill in the art will readily appreciate that the terms “top” and “bottom” are generally used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of the rotary separator 500 as implemented.

[0076] Figure 5D shows a perspective cutout view of a perimeter seal and perimeter sealing passage located between the stationary housing and the rotatable vane assembly of the rotary separator of Figures 5A-5C according to some implementations. The perspective cutout view illustrates a magnified view of an upper portion of the rotatable drum 512 including the pitot groove 518 defined by the rotatable drum 512. An opening of a pitot tube or pickup tube 554 may be positioned in the pitot groove 518. The rotatable drum 512 has a sloped inner wall 572 along which liquid travels in an upwards direction by centrifugal force. An opening 574 is defined between an upstream lip 576 of the rotatable drum 512 and the sloped inner wall 572 of the rotatable drum 512, where the opening 574 provides passageway for the liquid to reach the pitotgroove 518. The pitot groove 518 is formed in the sloped inner wall 572 so that a wall thickness of the sloped inner wall 572 is reduced or substantially reduced at the pitot groove 518. In some implementations, the pitot groove 518 is adjacent to the upstream lip 576, where the pitot groove 518 is defined by a vertical wall 582 at the upper portion of the rotatable drum 512 and a horizontal overhang 584 at the upper portion of the rotatable drum 512. The horizontal overhang 584 serves as a ceiling to the pitot groove 518 and the vertical wall 582 serves as the wall to the pitot groove 518. A person having ordinary skill in the art will readily appreciate that the terms “upstream” and “downstream,” the terms “upwards” and “downwards,” and the terms “vertical” and “horizontal” are generally used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of the rotary separator 500 as implemented.

[0077] A perimeter sealing passage 552 is formed between the stationary housing 520 and the rotatable drum 512. The perimeter sealing passage 552 interfaces between the perimeter seal 550 and the seal cavity 530. The stationary housing 520 may further include overhanging protrusion 592 attached to the stationary housing 520. In some implementations, the overhanging protrusion 592 is a splash guard or component that extends downwards from the top plate 532 of the stationary housing 520. The overhanging protrusion 592 is located adjacent to the perimeter seal 550. The overhanging protrusion 592 is integrated with the stationary housing 520 and extends vertically into the bore 522. The overhanging protrusion 592 may also be referred to as a “drip edge” or “splash guard” that prevents the main process stream (e.g., binary mixture) from interacting directly with liquid in the pitot groove 518 and also prevents any liquid in the pitot groove 518 from splashing or drifting back into the main process stream. The overhanging protrusion 592 has a radially inward side that faces the central hub 514 and a radially outward side that faces the pitot groove 518. In some cases, it may be said that the radially inward side faces the central hub 514 and the radially outward side faces the inner wall of the rotatable drum 512, or that the radially inward side faces a flow of the binary mixture and the radially outward side faces a flow of the backpressure seal gas exiting the perimeter seal 550.

[0078] The perimeter sealing passage 552 is the internal sealing passage or pathway that fluidly connects the bore 522 to the seal cavity 530. The perimeter sealing passage 552 includes the internal sealing passage between the stationary housing 520 and the horizontal overhang 584 as well as the internal sealing passage between the stationary housing 520 and the vertical wall 582. The perimeter sealing passage 552 includes an enclosed volume between corresponding surfaces of the rotatable drum 512 and the stationary housing 520. The corresponding surfaces are designed in a manner to prevent liquid or particulate ingress into the seal cavity 530 and / or expel liquid or particulate that enters into the perimeter sealing passage 552. Aspects of the designof the perimeter sealing passage 552 and the overhanging protrusion 592 are discussed in detail below with respect to Figure 5E.

[0079] Figure 5E shows a cross-sectional schematic cutout view of the perimeter sealing passage of Figure 5D for preventing ingress of liquid or particulate according to some implementations. The perimeter sealing passage 552 that connects the perimeter seal 550 with the seal cavity 530 may have a straight or substantially straight geometry. This provides a streamlined seal throat that facilitates gas flow to the perimeter seal 550. Rather than a tortuous pathway or labyrinth-type features, the straight or substantially straight geometry reduces pressure drop and enhances flow between a gas supply and the perimeter seal 550. Thus, the backpressure seal gas (represented by the dashed arrows) can flow more effectively and with lower pressure drop from the seal cavity 530 to the perimeter seal 550 through the perimeter sealing passage 552, providing an improved seal against liquid intrusion.

[0080] The perimeter sealing passage 552 also provides a wide seal cavity with sharp corners at its interface with the perimeter seal 550. A cross sectional area or width of the perimeter sealing passage 552 is greater than a cross sectional area or width of the perimeter seal 550. This provides higher static pressure relative to the perimeter seal 550. There are sharp convex comers at the interface between the perimeter sealing passage 552 and the perimeter seal 550, where the interface provides sharp convex comers on rotating and stationary sides. In some implementations, the sharp convex corners are 90 degrees, acute (less than 90 degrees), or obtuse (greater than 90 degrees and less than 180 degrees). The sharp convex corners may serve as a backstop to halt or limit liquid intrusion beyond the perimeter seal 550 into the perimeter sealing passage 552, where sharp convex corners generate an effective contact angle greater than 90 degrees for any liquid that reaches this point. The cross sectional area or width of the perimeter sealing passage 552 is also dimensioned to be sufficiently wide to prevent any bridging by a liquid originating from the perimeter seal 550.

[0081] The perimeter seal 550 is designed to be relatively short and narrow. A length of the perimeter seal 550 is greater than a gap width of the perimeter seal 550. In some cases, the length of the perimeter seal 550 is at least two times greater than a gap width of the perimeter seal 550. The gap width of the perimeter seal 550 is narrow, where the gap width is between about 0.002 inches and about 0.1 inches, or between about 0.005 inches and about 0.05 inches. The gap width is designed to be approximately equal to, less than, or only slightly larger than the smallest expected liquid droplet diameter. This prevents liquid droplets from freely moving or splashing into the perimeter seal 550 and penetrating through the perimeter seal 550. Furthermore, the narrow gap facilitates acceleration of the backpressure seal gas through the perimeter seal 550 to provide high-velocity gas flow through the perimeter seal 550. The high-velocity gas flowprevents intrusion of liquid droplets smaller than the gap width by generating an aerodynamic drag force on the liquid droplets that decelerates and expels them from the perimeter seal 550. Moreover, the high-velocity gas flow prevents further ingress of liquid droplets by generating an aerodynamic shear force on the liquid droplets that overcomes adhesive surface tension forces. The narrow gap width of the perimeter seal 550 is also configured to generate a high static pressure drop between the seal cavity 530 and the bore 522 to provide a positive pressure seal in addition to the dynamic pressure generated by the high-velocity gas flow. Additionally, the gap width of the perimeter seal 550 is configured to limit capillary (suction) pressure, where the backpressure seal gas can flow through the gap width of the perimeter seal 550 in a manner to counteract the capillary pressure and provide a motive net force to drive liquid out of the perimeter seal 550.

[0082] An exit of the perimeter seal 550 may be designed in a manner to further drive liquid droplets away from perimeter seal 550. The exit interfaces with the stationary housing 520 at the radial outward side of the overhanging protrusion 592, and the exit also interfaces with the rotatable drum 512 at the horizontal overhang 584. As shown in Figure 5E, the exit at the stationary side includes a step 594 and a shoulder 596, where the step 594 runs transverse relative to the exit at the perimeter seal 550. The step 594 transitions into the shoulder 596 such that the shoulder 596 runs transverse to the step 594. The step 594 is small and straight and the shoulder 596 is short and straight, which allows the high-velocity gas flow exiting the perimeter seal 550 to be converted to a jet that bends or “attaches” itself as a flow along the surfaces of the stationary side. The height of the step 594 and the length of the shoulder 596 are configured to facilitate high-velocity gas flow exiting the perimeter seal 550 in a manner that prevents liquid droplet attachment on the stationary side adjacent to the exit of the perimeter seal 550. This further prevents liquid encroachment into the perimeter seal 550. The sharp convex corner of the step 594 followed by the subsequent short, straight shoulder 596 also prevents liquid films or droplets from spreading into the perimeter seal 550. The shoulder 596 may transition to a sloped or curved surface along the radially outward side of the overhanging protrusion 592. Though the corners formed by the step 594 and the shoulder 596 are illustrated as 90 degrees, it will be understood that the comers may be sharp convex corners that are acute or obtuse in some other implementations.

[0083] Also as shown in Figure 5E, the exit at the rotating side includes a slope 586 that runs partially along a bottom surface of the horizontal overhang 584. The slope 586 may be linear or at least substantially linear, where the slope 586 has an opening angle of about 30 degrees or greater, about 40 degrees or greater, or about 45 degrees or greater. The opening angle of the slope 586 is configured to enable the centrifugal force generated by the rotatable drum 512 to overcome surface adhesion of liquid droplets and drive any liquid on the surface of the slope 586 away fromthe perimeter seal 550. The large opening angle also enhances flow of the high-velocity gas flow that exits the perimeter seal 550, thereby enhancing stable “attachment” of the jet that bends or “attaches” itself as a flow along the surfaces of the stationary side. The sharp corner of the slope 586 that intersects with the exit of the perimeter seal 550 further prevents liquid films or droplets from spreading into the perimeter seal 550.

[0084] In some implementations, the perimeter seal 550 may be configured with alternative shapes, orientations, and dimensions to provide enhanced seal functionality. In some cases, the perimeter seal 550 may be oriented substantially radial or angled, rather than axial. The perimeter seal 550 may additionally or alternatively include radial or angled runs to leverage centrifugal acceleration to prevent liquid ingress. The perimeter seal 550 may alternatively have multiple sections instead of being straight, where at least one of the sections may be oriented substantially radial or angled such that centrifugal acceleration produced by the rotatable drum 512 impedes liquid ingress through the perimeter seal 550. Various shapes and orientations of the perimeter seal 550 may serve to obstruct liquid access / ingress, especially under transient conditions.

[0085] As discussed earlier, an overhanging protrusion 592 is attached to the stationary housing 520 and is located adjacent to the perimeter seal 550, where the overhanging protrusion 592 serves as a drip edge or splash guard. The radially outward side of the overhanging protrusion 592 faces the pitot groove 518, where the radially outward side blocks splash, spray, or overflowing liquid escaping the pitot groove 518 and moving upstream into the main process stream, thereby retaining and redirecting the liquid (e.g., condensate) into the catchment area. The radially outward side of the overhanging protrusion 592 may be curved or at least partially curved. The radially inward side of the overhanging protrusion 592 faces the central hub 514 and faces the main process stream. The radially inward side of the overhanging protrusion 592 may be straight or at least substantially straight. The radially inward side of the overhanging protrusion 592 may be vertical or at least substantially vertical. The overhanging protrusion 592 prevents the main process stream from interacting with liquid in the pitot groove 518. Splash and atomization of liquid may occur at the pitot groove 518 via a pitot tube or pickup tube that creates secondary spray, where the overhanging protrusion 592 functions as a splash guard against the secondary spray of liquid from reaching the bore 522 where the main process stream flows. That way, the liquid can be recaptured and reprocessed in the pitot groove 518 with minimal loss.

[0086] The radially outward side of the overhanging protrusion 592 starts straight at the shoulder 596 adjacent to the exit of the perimeter seal 550 and transitions to a curved surface. The curved surface may have a relatively large curvature radius (such as between about 0.1 inches to about 1 inch). The curved surface ensures that the high-velocity gas flow exiting the perimeter seal 550 is flowed as a Coanda wall jet that stays “attached” along the curved surface. This keepsthe high-velocity gas flow to continue flowing along the surface of overhanging protrusion 592 to prevent liquid droplet attachment and further push liquid away from the perimeter seal 550. The high-velocity gas flow traveling along the shape / geometry of the overhanging protrusion 592 is configured to direct splash from the pitot groove 518 away from the perimeter seal 550 and into the catchment area of the rotatable vane assembly 510.

[0087] The radially outward side and the radially inward side of the overhanging protrusion 592 intersect at a tip or drip edge 598. In some implementations, the radially outward side consists of the curved surface that terminates at the drip edge 598. In some implementations, the radially outward side of the overhanging protrusion 592 further includes a straight surface in addition to the curved surface, where the curved surface transitions to the straight surface nearer the drip edge 598. Alternatively, the curved surface transitions from the straight surface to the curved surface nearer to the drip edge 598.

[0088] The main process stream (e.g., binary mixture) flows on the radially inward side of the overhanging protrusion 592, and the backpressure seal gas exiting the perimeter seal 550 flows along the radially outward side of the overhanging protrusion 592. Accordingly, high-speed flows on both sides of the overhanging protrusion 592 intersect at the drip edge 598. This provides motive force to shear off liquid droplets that have gathered at the drip edge 598, further preventing liquid from reaching the perimeter seal 550.

[0089] The drip edge 598 merges the flow from the main process stream on the radially inward side with the flow from the backpressure seal gas on the radially outward side. In some implementations, the drip edge 598 is a sharp tip rather than a rounded edge. The radially inward side and the radially outward side merge at the drip edge 598, where the drip edge 598 forms an opening angle. The opening angle of the drip edge 598 may be less than about 50 degrees, between about 20 degrees and about 50 degrees, less than about 40 degrees, or between about 30 degrees and about 40 degrees. The opening angle of the drip edge 598 may be configured to allow for smooth merging of the main process steam flowing along the radially inward side of the overhanging protrusion 592 and the backpressure seal gas flowing along the radially outward side of the overhanging protrusion 592, where turbulation of flow is minimized around the overhanging protrusion 592 and in the pitot groove 518.

[0090] In some implementations, the backpressure seal gas includes recirculated gas that originates from portions of the separated gas stream. In Figure 5B, the main process stream enters the rotary separator 500 as a binary mixture and exits the rotary separator 500 as a separated gas stream. In Figure 51, the separated gas stream is converted to the backpressure seal gas, where a flow of the backpressure seal gas is indicated by dashed arrows.

[0091] A portion of the separated gas stream may be driven by a pressurized gas driver 580 such as a fan, a compressor, or a combination thereof. Figure 5F shows a perspective view of a rotatable vane assembly and a drive shaft of the rotary separator of Figures 5A-5E according to some implementations. The rotatable vane assembly 510 includes a plurality of vanes 516 that extend between a central hub 514 and an inner wall of a rotatable drum 512. Each of the plurality of vanes 516 include features such as grooves for capturing liquid in the main process stream. The central hub 514 may house the rotatable shaft or drive shaft 542 for driving rotation of the rotatable vane assembly 510. The rotatable vane assembly 510 includes the rotatable drum 512 having a pressurized gas driver 580 such as a fan. The pressurized gas driver 580 is located at a downstream end of the rotatable vane assembly 510. The pressurized gas driver 580 may surround or be positioned about an outer wall of the rotatable drum 512. The pressurized gas driver 580 may include multiple rotatable blades and / or stator vanes. During operation of the rotary separator 500, the pressurized gas driver 580 may direct separated gas as backpressure seal gas to internal sealing passages of the rotary separator 500.

[0092] The pressurized gas driver 580 may be connected to the rotatable drum 512, or connected to both the rotatable drum 512 and the stationary housing 520. For example, the pressurized gas driver 580 may be integrated with the rotatable drum 512 and the stationary housing 520. The pressurized gas driver 580 ingests a portion of the separated gas stream from a downstream end of the rotary separator 500 and re-routes it to the seal cavity 530 as recirculated separated gas (i.e., backpressure seal gas). The pressurized gas driver 580 pressurizes the recirculated separated gas and drives it through the seal cavity 530 and the perimeter sealing passage 552. In some implementations, the pressurized gas driver 580 may be located at a downstream end of the rotatable drum 512, where the pressurized gas driver 580 may be fluidly connected to the outlet 528 of the rotary separator 500 and fluidly connected to the seal cavity 530.

[0093] In some implementations, the pressurized gas driver 580 includes a fan, a compressor, or a combination of a fan and compressor that captures a portion of the separated gas stream from the outlet 528 to the seal cavity 530. The fan, compressor, or combination thereof drives the portion of the separated gas stream as recirculated separated gas through the seal cavity 530 and the perimeter sealing passage 552. In some implementations, the pressurized gas driver 580 includes a multi-stage compressor or multi-stage fan. The multi-stage compressor or multi-stage fan may include multiple rows of rotatable blades connected to the rotatable drum 512 and at least one stator (e.g., stator vane) connected to the stationary housing 520. The rotatable blades and stator vane(s) may be straight, angled, or curved. The rotatable blades and stator vane(s) in different rows may have the same or different lengths, heights, and / or cross-sectional shapes. The rotatable blades and stator vane(s) in different rows may have different numbers and / or spacing ofblades / vanes. In particular, the number, spacing, and height of substantially radial rotor blades and stator vane rows, and the channels between them, may be chosen and sized such that they allow the rotor blades and stator vanes to slide through or past one another axially during assembly. Gaps between rotatable features of the compressor and the stationary housing 520 may be smooth and tight to minimize gas and pressure losses in the compressor without significantly increasing friction. Figure 5G shows an isometric view of a stator (e.g., stator vane) for a multi-stage compressor. The stator 548 shown in Figure 5G may have multiple rows of blades or vanes. Figure 5H shows an isometric view of a rotor (e.g., bottom half of the rotatable vane assembly) for a multi-stage compressor. The rotor 588 may have a plurality of blades or vanes. Together, the stator in Figure 5G and the rotor in Figure 5H form the multi-stage compressor.

[0094] In some implementations, the pressurized gas driver 580 is a multi-stage axial compressor or multi-stage radial compressor with several rows of rotatable blades attached to the outside, bottom, and / or inside of the rotatable drum 512 and with several rows of stator vanes attached to the stationary housing 520. In some implementations, the pressurized gas driver 580 is a radial or centrifugal compressor with at least one rotatable blade row attached to the rotatable drum 512 and with at least one row of stator vanes attached to the stationary housing 520.

[0095] Figure 51 shows a perspective cross-sectional view of the rotary separator of Figures 5 A-5H with arrows indicating directions of pressurized gas flow for a sealing assembly according to some implementations. A gas flow path of the backpressure seal gas is indicated by the dashed arrows. A first gas flow path 558 of the backpressure seal gas starts at the pressurized gas driver 580 adjacent to the outlet 528 of the rotary separator 500, continues through the seal cavity 530 defined between the rotatable drum 512 and the stationary housing 520, continues through the perimeter sealing passage 552, and continues through the perimeter seal 550. Thus, the first gas flow path 558 of the backpressure seal gas primarily travels through a space between the rotatable drum 512 and the stationary housing 520. In some implementations, the space may be a mostly straight axial cylindrical chamber that is in fluid communication with the pressurized gas driver 580 at the downstream end and with the perimeter seal 550. In some implementations, a cylindrical cross-sectional width gradually increases from the pressurized gas driver 580 to the perimeter seal 550 to act as a gradually expanding diffusor to optimize pressure recovery and provide a higher-pressure gas flow to the perimeter seal 550. In some implementations, the first gas flow path 558 may include additional features such as constrictions, orifices, expansions, and sharp turns to meter the gas flow and pressure at the perimeter seal 550. In some implementations, vanes or similar features may be attached to the stationary housing 520 along the first gas flow path 558 to straighten and direct the gas flow and minimize swirl. The backpressure seal gas flowing through the first gas flow path 558 may provide continuous dry gas flow between therotatable drum 512 and the stationary housing 520 to minimize condensation in the space between the rotatable drum 512 and the stationary housing 520.

[0096] A second gas flow path 568 of the backpressure seal gas starts at the pressurized gas driver 580, passes through the plurality of vanes 516 to the central hub 514, continues through the chamber volume 540 of the central hub 514, and continues through the hub seal 560. The hub seal 560 may include opening(s) at downstream and upstream ends of the central hub 514. The plurality of vanes 516 may be hollow, providing passageway for the backpressure seal gas from the seal cavity 530 to the chamber volume 540. In other words, hollowed vanes of the plurality of vanes 516 may provide an internal passage that spans from the central hub 514 to the radially outward edge of the rotatable drum 512. Alternatively, the backpressure seal gas may flow through hollowed spars that connect from the stationary housing 520 to the central hub 514 instead of through hollowed vanes. The backpressure seal gas that flows through the second gas flow path 568 passes through and around motors and / or bearings in the central hub 514, thereby providing convective cooling for the motors and / or bearings as well as to prevent stagnant moist air from converting into condensation. In some implementations, the second gas flow path 568 may include additional features such as constrictions, orifices, expansions, and sharp turns to meter the gas flow and pressure at the hub seal 560 and apportion an amount of flow to the various openings associated with the hub seal 560.

[0097] In some implementations, one or more heaters 570 may be placed adjacent or proximate to the pressurized gas driver 580. The one or more heaters 570 may be implemented as film heaters that wrap around a perimeter of the rotatable vane assembly 510 or the stationary housing 520. As shown in Figure 5F, the one or more heaters 570 include a film heater that wraps around the rotatable vane assembly 510. Film heaters may be thin strips that may be affixed to an inside and / or outside of the rotatable drum 512. Such film heaters may be positioned above or right above the fan, compressor, or combination of the fan and compressor. Though the one or more heaters 570 are indicated as a “strip” it will be understood that the one or more heaters 570 may be implemented as any number of designs adjacent to the pressurized gas driver 580. For instance, the one or more heaters 570 may include one or more “block” heaters positioned around a perimeter of the rotatable vane assembly 510 or stationary housing 520. The one or more heaters 570 may serve to raise the temperature and lower the relative humidity of the recirculated separated gas to prevent or otherwise limit condensation. The one or more heaters 570 may function to increase static pressure or reduce relative humidity. That way, the backpressure seal gas flowing through the seal cavity 530 and the perimeter sealing passage 552 is dry or substantially dry. In some implementations, the one or more heaters 570 are located on the stationary housing 520. In some implementations, the one or more heaters 570 are embedded or integrated with thepressurized gas driver 580. For example, the one or more heaters 570 may be integrated with or embedded in stator walls or stator vanes of the pressurized gas driver 580. In some implementations, the one or more heaters 570 may be placed anywhere along the seal cavity 530 or the perimeter sealing passage 552 to reduce condensation in the backpressure seal gas.

[0098] In addition or in the alternative to recirculated gas, the backpressure seal gas may include external gas from an external gas driver or external gas supply (not shown). In some implementations, the external gas driver includes an external fan or external pump. The external gas driver may circulate additional gas flow through the seal cavity 530 and / or the perimeter sealing passage 552. The external gas driver may be located outside the rotary separator 500. In one example, the external gas driver may draw air from cabin air outside the rotary separator 500. In another example, the external gas driver may draw air from a component upstream of the rotary separator 500 such as a heat exchanger. Alternatively, the external gas driver may be located on the stationary housing 520 of the rotary separator 500. The additional gas flow may enter through tubing to ports or openings in fluid communication with the seal cavity 530 and / or the perimeter sealing passage 552. In some cases, the additional gas flow may be drawn from separated gas discharged at the outlet 528 of the rotary separator 500, where the additional gas flow may be delivered through tubing, ports, and / or openings in fluid communication with the seal cavity 530 and the perimeter sealing passage 552. The additional gas flow serves to prevent or otherwise limit ingress of liquid or particulate into the seal cavity 530 and the perimeter sealing passage 552. In some implementations, the additional gas flow serves as the backpressure seal gas (in place of recirculated separated gas). In some implementations, the backpressure seal gas includes both the recirculated separated gas from the pressurized gas driver 580 and the additional gas flow from the external gas driver. Accordingly, the backpressure seal gas to the perimeter seal 550 may be provided by the pressurized gas driver 580 connected to the rotatable drum 512 and the external gas driver connected to the stationary housing 520 or outside the rotary separator 500.

[0099] Figure 5J shows a cross-sectional schematic cutout view of a hub sealing passage of the rotary separator of Figures 5A-5I for preventing ingress of liquid or particulate according to some implementations. A hub sealing passage 562 may be defined as enclosed volume between corresponding surfaces of the rotatable drum 512 at the central hub 514 and the stationary housing 520 at the central hub 514. In particular, the hub sealing passage 562 may be defined between corresponding surfaces of the rotatable drum 512 at the central hub 514 and a top plate 532 of the stationary housing 520, and defined between corresponding surfaces of the rotatable drum 512 at the central hub 514 and a bottom plate 534 of the stationary housing 520. Backpressure seal gas flows to the hub seal 560 through the hub sealing passage 562 to prevent ingress of liquid or particulate into the hub sealing passage 562 and the chamber volume 540 of the central hub 514.

[0100] The hub sealing passage 562 is located in the central hub 514. The hub sealing passage 562 is fluidly connected between the chamber volume 540 and the hub seal 560. The hub sealing passage 562 is oriented, shaped, dimensioned, and incorporated with features to limit ingress of liquid at the hub seal 560. The hub sealing passage 562 that connects the hub seal 560 with the chamber volume 540 is oriented substantially axially, radially, or a combination of both. The hub sealing passage 562 also provides a wide seal cavity with sharp corners at its interface with the hub seal 560. The cross-sectional area or width of the hub sealing passage 562 is greater than the cross-sectional area or width of the hub seal 560. This provides higher static pressure relative to the hub seal 560. There are sharp convex corners at the interface between the hub sealing passage 562 and the hub seal 560, where the interface provides sharp convex comers on rotating and stationary sides. In some implementations, the sharp convex corners are 90 degrees, acute (less than 90 degrees), or obtuse (greater than 90 degrees and less than 180 degrees). The sharp convex corners may function as a backstop (e.g., first backstop) to halt or limit liquid intrusion beyond the hub seal 560 into the hub sealing passage 562, where the sharp convex corners generate an effective contact angle greater than 90 degrees for any liquid that reaches this point. A second backstop may be provided at a top of the hub sealing passage 562 to function as a safety buffer. The first and second backstops may be aided by centrifugal force to limit ingress of liquid. The cross sectional area or width of the hub sealing passage 562 is also dimensioned to be sufficiently wide to prevent any bridging by a liquid originating from the hub seal 560.

[0101] The hub seal 560 is designed to be relatively short and narrow. A length of the hub seal 560 is greater than a gap width of the hub seal 560. In some cases, the length of the hub seal 560 is at least two times greater than a gap width of the hub seal 560. The gap width of the hub seal 560 is narrow, where the gap width is between about 0.002 inches and about 0.1 inches, or between about 0.005 inches and about 0.05 inches. The gap width is designed to be approximately equal to, less than, or only slightly larger than the smallest expected liquid droplet diameter. This prevents liquid droplets from freely moving or splashing into the hub seal 560 and penetrating through the hub seal 560. Moreover, the narrow gap facilitates acceleration of the backpressure seal gas through the hub seal 560 to provide high-velocity gas flow through the hub seal 560. The high-velocity gas flow prevents intrusion of liquid droplets smaller than the gap width by generating an aerodynamic drag force on the liquid droplets that decelerates and expels them from the hub seal 560. Furthermore, the high-velocity gas flow prevents further ingress of liquid droplets by generating an aerodynamic shear force on the liquid droplets that overcomes adhesive surface tension forces. The narrow gap width of the hub seal 560, combined with sharp convex corners on both sides, are also configured to generate a high static pressure drop between the chamber volume 540 and the bore 522 to provide a positive pressure seal in addition to the dynamicpressure generated by the high-velocity gas flow. Additionally, the gap width of the hub seal 560 is configured to limit capillary (suction) pressure, where the backpressure seal gas can flow through the gap width of the hub seal 560 in a manner to counteract the capillary pressure and provide a motive net force to drive liquid out of the hub seal 560.

[0102] An exit of the hub seal 560 may be designed in a manner to further drive liquid droplets away from hub seal 560. In some implementations as shown in Figure 5H, the exit has sharp, approximately 90 degree convex corners on both sides to prevent liquid films or droplets from spreading into the hub seal 560. In some implementations, the exit of the hub seal 560 is slanted, i.e., oriented axially and radially outward, such that it forms a sharp and acute convex comer, or drip edge, at the upstream or stationary side of the exit, and an obtuse sharp convex corner on the other side.

[0103] The hub seal 560 may be oriented more horizontally relative to the perimeter seal 550. The hub seal 560 may be oriented more horizontally because the centrifugal force assists in driving liquid away from the central hub 514. As such, the hub seal 560 may be oriented perpendicular to a direction of flow of the binary mixture. The perimeter seal 550 may be oriented more vertically because the centrifugal force works against driving the liquid away from the seal cavity 530. As such, the perimeter seal 550 may be oriented parallel to the direction of flow of the binary mixture.

[0104] The central hub 514 may house various components such as the rotatable shaft 542, motor 544, and bearing(s). As the backpressure seal gas flows through the chamber volume 540, one or more metering holes 578 may limit flow of the backpressure seal gas through different parts of the chamber volume 540. Specifically, the metering holes 578 may be designed to meter flow of the backpressure seal gas through the motor 544 and to the hub sealing passage 562. The number of metering holes 578 and the diameter of each of the metering holes 578 may be optimized to distribute the flow of the backpressure seal gas to the motor 544 to adequately cool the motor 544 and limit the ingress of liquid through the hub seal 560.

[0105] In some implementations, the backpressure seal gas is directed to flow to the hub sealing passage 562 located at an upstream end and a downstream end of the central hub 514. In some implementations, the backpressure seal gas is directed to flow to hub sealing passage 562 located at only the upstream end of the central hub 514. In some cases, liquid is not likely to reach and penetrate the hub seal 560 at the downstream end of the central hub 514. Accordingly, the backpressure seal gas is not needed to flow to the hub seal 560 at the downstream end of the central hub 514.Conclusion

[0106] Although the foregoing disclosed systems, methods, apparatuses, processes, and compositions have been described in detail within the context of specific implementations for the purpose of promoting clarity and understanding, it will be apparent to one of ordinary skill in the art that there are many alternative ways of implementing foregoing implementations which are within the spirit and scope of this disclosure. Accordingly, the implementations described herein are to be viewed as illustrative of the disclosed inventive concepts rather than restrictively, and are not to be used as an impermissible basis for unduly limiting the scope of any claims eventually directed to the subject matter of this disclosure.

Claims

CLAIMSWhat is claimed is:

1. A rotary separator comprising: a stationary outer component; a rotatable inner component retained within the stationary outer component, wherein an internal sealing passage is defined between the rotatable inner component and the stationary outer component, wherein the rotary separator is configured to receive a two-phase mixture comprising a gas stream and liquid or particulates at an inlet of the rotary separator and to discharge separated gas at an outlet of the rotary separator; and a pressurized gas driver configured to recirculate the separated gas from the outlet through an internal passage as a backpressure seal gas, wherein the backpressure seal gas is configured to prevent ingress of liquid or particulates into the internal passage.

2. The rotary separator of claim 1, wherein the rotatable inner component comprises: a rotatable drum; and a plurality of vanes arranged about the rotatable drum and connected to the rotatable drum at an inner wall of the rotatable drum.

3. The rotary separator of claim 2, further comprising: a non-contacting perimeter seal configured to prevent ingress of liquid or particulates into a seal cavity between an outer wall of the rotatable drum and the stationary outer component, wherein the backpressure seal gas is circulated through the seal cavity to the non-contacting perimeter seal.

4. The rotary separator of claim 3, wherein a width of a seal gap of the non-contacting perimeter seal is between about 0.002 inches and about 0.1 inches.

5. The rotary separator of claim 3, wherein a perimeter sealing passage fluidly connects the non-contacting perimeter seal with the seal cavity, wherein a cross-sectional area of the perimeter sealing passage is greater than a cross-sectional area of a seal gap of the non-contacting perimeter seal.

6. The rotary separator of claim 5, wherein an interface between the perimeter sealing passage and the non-contacting perimeter seal includes sharp convex corners that are 90 degrees, acute, or obtuse.

7. The rotary separator of claim 3, wherein the stationary outer component comprises: an overhanging protrusion positioned adjacent to the non-contacting perimeter seal and extends downwards from the inlet of the rotary separator, wherein the overhanging protrusion comprises a radially inward side that faces a flow of the two-phase mixture and a radially outwardside that faces a flow of the backpressure seal gas that exits from the non-contacting perimeter seal.

8. The rotary separator of claim 7, wherein the radially outward side and the radially inward side of the overhanging protrusion merges at a tip, wherein the tip forms an opening angle between the radially inward side and the radially outward side that is less than about 40 degrees.

9. The rotary separator of claim 7, wherein the radially inward side is vertical or substantially vertical, and the radially outward side includes a curved surface or substantially curved surface.

10. The rotary separator of claim 3, further comprising: a central hub that encloses a rotatable shaft and one or more motors in a chamber volume and configured to rotate the rotatable inner component; and a non-contacting hub seal configured to prevent ingress of liquid or particulates into the chamber volume, wherein the backpressure seal gas is circulated through the chamber volume to the non-contacting hub seal.

11. The rotary separator of claim 10, wherein a hub sealing passage fluidly connects the noncontacting hub seal and the chamber volume, wherein the hub sealing passage is defined between corresponding surfaces of the rotatable inner component at the central hub and the stationary outer component at the central hub.

12. The rotary separator of claim 10, wherein the pressurized gas driver is configured to circulate the backpressure seal gas to the chamber volume.

13. The rotary separator of claim 12, where the backpressure seal gas is routed from the seal cavity to the chamber volume via hollow vanes of a plurality of vanes of the rotatable inner component.

14. The rotary separator of claim 12, wherein the backpressure seal gas is routed from the seal cavity to the chamber volume via hollowed spars that connect from the stationary outer component to the central hub.

15. The rotary separator of claim 10, wherein the non-contacting hub seal is oriented perpendicular to a direction of flow of the two-phase mixture, and wherein the non-contacting perimeter seal is oriented parallel to the direction of flow of the two-phase mixture.

16. The rotary separator of claim 1, wherein the pressurized gas driver comprises one or both of a fan and a compressor.

17. The rotary separator of claim 1, wherein pressurized gas driver is located adjacent to the outlet of the rotary separator.

18. The rotary separator of claim 1, further comprising: one or more heaters positioned adjacent to the pressurized gas driver to increase static pressure or reduce relative humidity.

19. The rotary separator of claim 1, further comprising: an external gas driver configured to circulate additional gas flow through the internal passage to further prevent ingress of liquid or particulate into the internal passage.

20. A rotary separator comprising: a stationary outer component; a rotatable inner component retained within the stationary outer component, wherein an internal sealing passage is defined between the rotatable inner component and the stationary outer component, wherein the rotary separator is configured to receive a two-phase mixture comprising a gas stream and liquid or particulates at an inlet of the rotary separator and to discharge separated gas at an outlet of the rotary separator; and an external gas driver configured to circulate gas through an internal passage as a backpressure seal gas, wherein the backpressure seal gas is configured to prevent ingress of liquid or particulates into the internal passage.

21. The rotary separator of claim 20, wherein the rotatable inner component comprises a rotatable drum, and wherein the rotary separator further comprises: a non-contacting perimeter seal configured to prevent ingress of liquid or particulates into a seal cavity between an outer wall of the rotatable drum and the stationary outer component, wherein the backpressure seal gas is circulated through the seal cavity to the non-contacting perimeter seal.

22. The rotary separator of claim 21, wherein a width of a seal gap of the non-contacting perimeter seal is between about 0.002 inches and about 0.1 inches.

23. The rotary separator of claim 21, wherein a perimeter sealing passage fluidly connects the non-contacting perimeter seal with the seal cavity, wherein a cross-sectional area of the perimeter sealing passage is greater than a cross-sectional area of a seal gap of the non-contacting perimeter seal.

24. The rotary separator of claim 23, wherein an interface between the perimeter sealing passage and the non-contacting perimeter seal includes sharp convex corners that are 90 degrees, acute, or obtuse.

25. The rotary separator of claim 21, wherein the stationary outer component comprises: an overhanging protrusion positioned adjacent to the non-contacting perimeter seal and extends downwards from the inlet of the rotary separator, wherein the overhanging protrusion comprises a radially inward side that faces a flow of the two-phase mixture and a radially outward side that faces a flow of the backpressure seal gas that exits from the non-contacting perimeter seal.

26. The rotary separator of claim 25, wherein the radially outward side and the radially inward side of the overhanging protrusion merges at a tip, wherein the tip forms an opening angle between the radially inward side and the radially outward side that is less than about 40 degrees.

27. The rotary separator of claim 25, wherein the radially inward side is vertical or substantially vertical, and the radially outward side includes a curved surface or substantially curved surface.

28. The rotary separator of claim 21, further comprising: a central hub that encloses a rotatable shaft and one or more motors in a chamber volume and configured to rotate the rotatable inner component; and a non-contacting hub seal configured to prevent ingress of liquid or particulates into the chamber volume, wherein the backpressure seal gas is circulated through the chamber volume to the non-contacting hub seal.

29. The rotary separator of claim 28, wherein a hub sealing passage fluidly connects the noncontacting hub seal and the chamber volume, wherein the hub sealing passage is defined between corresponding surfaces of the rotatable inner component at the central hub and the stationary outer component at the central hub.

30. The rotary separator of claim 28, wherein the backpressure seal gas is routed from the seal cavity to the chamber volume via hollowed spars that connect from the stationary outer component to the central hub.

31. The rotary separator of claim 28, wherein the non-contacting hub seal is oriented perpendicular to a direction of flow of the two-phase mixture, and wherein the non-contacting perimeter seal is oriented parallel to the direction of flow of the two-phase mixture.

32. The rotary separator of claim 21, further comprising: one or more heaters positioned adjacent to the external gas driver to increase static pressure or reduce relative humidity.

33. A seal assembly for a rotary separator configured to separate a gas from liquid or particulate, the seal assembly comprising: a stationary housing; a rotatable vane assembly retained within the stationary housing, wherein the rotatable vane assembly comprises a rotatable drum and a plurality of vanes arranged about a central hub and extending radially outwardly from the central hub to an inner wall of the rotatable drum; a perimeter seal configured to prevent ingress of the liquid or particulate into a seal cavity defined between an outer wall of the rotatable drum and the stationary housing; and a hub seal configured to prevent ingress of the liquid or particulate into a chamber volume of the central hub that encloses one or both of a rotatable shaft and a motor.

34. The seal assembly of claim 33, further comprising: a pressurized gas driver configured to circulate a backpressure seal gas through the seal cavity to the perimeter seal via a first gas flow path and circulate the backpressure seal gas from the seal cavity through the chamber volume to the hub seal via a second gas flow path, wherein the pressurized gas driver comprises one or both of a fan and a compressor.

35. The seal assembly of claim 33, wherein the stationary housing further comprises: an overhanging protrusion positioned adjacent to the perimeter seal, wherein the overhanging protrusion comprises a radially inward side that faces the central hub and a radially outward side that faces the inner wall of the rotatable drum, wherein the radially outward side and the radially inward side merge at a drip edge.

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