An attachment and retaining mechanism is described for removably attaching a rotating filter element to a rotating shaft. The rotating filter element includes a filter media that is driven by a drive mechanism that rotates the rotating shaft. The filter element is removably attached to the rotating shaft such that the filter element and filtration system can be periodically replaced and/or serviced. In some arrangements, the drive shaft includes a D-shaped section that interacts with a mating section of the filter element sleeve of the rotating filter element. In other arrangements, the drive shaft includes at least one flat drive surface.

Described are multi-stage drum filtration systems including a primary rotary drum filter stage, at least one passive filter stage, and a main fan configured to create a vacuum on an inlet side of the primary rotary drum filter stage. The multi-stage drum filtration system may also include a HEPA filter stage. A controller may be configured to control a speed of the main fan to maintain an inlet vacuum to the primary rotary drum filter stage that corresponds to an inlet vacuum set point input.

Described are multi-stage drum filtration systems including a primary rotary drum filter stage, at least one passive filter stage, and a main fan configured to create a vacuum on an inlet side of the primary rotary drum filter stage. The multi-stage drum filtration system may also include a HEPA filter stage. A controller may be configured to control a speed of the main fan to maintain an inlet vacuum to the primary rotary drum filter stage that corresponds to an inlet vacuum set point input.

The invention relates to an accessory gearbox (10) for a turbomachine, said gearbox being equipped with an air/oil separator (12) and comprising a casing (24) in which intermeshing pinions are mounted, one (18) of which is solidly connected to a coaxial shank (22) for driving at least one membrane filter (35) of the separator, characterized in that the membrane filter is mounted directly on a web of the pinion (18) inside the casing.

Assembly to be used to filter a fluid, containing a housing (29) which comprises a housing base (50) and a housing upper part (30) connected removably to the housing base (50). An axial shaft (34, 35) extends at least partially through the filter element (32, 33) when the filter element (32, 33) is contained inside the housing (29). A lower bearing (44) is arranged between the axial shaft (34, 35) and the housing base (50) and underneath the filter element (32, 33) when a filter element (32, 33) is contained inside the housing (29). The housing (29) is able to contain a filter element (32, 33) within it and the filter element (32, 33) fits onto the axial shaft (34, 35) in such a way that the axial shaft (34, 35) is rotationally coupled to the filter element (32, 33). The filter assembly (20, 120) has no bearing above the filter element (32, 33).

Assembly to be used to filter a fluid, containing a housing (29) which comprises a housing base (50) and a housing upper part (30) connected removably to the housing base (50). An axial shaft (34, 35) extends at least partially through the filter element (32, 33) when the filter element (32, 33) is contained inside the housing (29). A lower bearing (44) is arranged between the axial shaft (34, 35) and the housing base (50) and underneath the filter element (32, 33) when a filter element (32, 33) is contained inside the housing (29). The housing (29) is able to contain a filter element (32, 33) within it and the filter element (32, 33) fits onto the axial shaft (34, 35) in such a way that the axial shaft (34, 35) is rotationally coupled to the filter element (32, 33). The filter assembly (20, 120) has no bearing above the filter element (32, 33).

Rotating coalescer crankcase ventilation (CV) systems are described. The described CV systems utilize a contact seal to seal a gap between a static side of a housing and a rotating coalescer inlet. The rotating coalescer may be driven mechanically, electrically, hydraulically, or the like. The contact seal can be formed via a soft solid or a liquid film created by oil. Accordingly, the contact seal is a hydrodynamic soft seal. The contact seal prevents the blowby gases from bypassing the filter element of the rotating coalescer. At the same time, the contact seal may be broken during positive blowby gas recirculation circumstances because the contact seal is a hydrodynamic soft seal.

Rotating coalescer crankcase ventilation (CV) systems are described. The described CV systems utilize a contact seal to seal a gap between a static side of a housing and a rotating coalescer inlet. The rotating coalescer may be driven mechanically, electrically, hydraulically, or the like. The contact seal can be formed via a soft solid or a liquid film created by oil. Accordingly, the contact seal is a hydrodynamic soft seal. The contact seal prevents the blowby gases from bypassing the filter element of the rotating coalescer. At the same time, the contact seal may be broken during positive blowby gas recirculation circumstances because the contact seal is a hydrodynamic soft seal.

Systems and methods for detecting a missing coalescing element in a CV system are described. In some arrangements, the described systems and methods prevent the assembly and/or re-assembly of the CV system without an appropriate coalescing element positioned within the CV system housing (e.g., during a coalescing element service operation). In some arrangements, the coalescing element depresses a spring-loaded component of a shaft that provides flow of bypass gases to the CV system. If the spring-loaded component is not depressed, significant restriction is introduced to the CV system, and an on-board-diagnostic system may detect high-crankcase pressure through existing crankcase pressure sensors and de-rate the internal combustion engine. In other arrangements, a spring-loaded mechanism within the shaft prevents a housing cover (e.g., a lid to the housing of the CV system) from being repositioned when a coalescing element is not installed within the housing.

Systems and methods for detecting a missing coalescing element in a CV system are described. In some arrangements, the described systems and methods prevent the assembly and/or re-assembly of the CV system without an appropriate coalescing element positioned within the CV system housing (e.g., during a coalescing element service operation). In some arrangements, the coalescing element depresses a spring-loaded component of a shaft that provides flow of bypass gases to the CV system. If the spring-loaded component is not depressed, significant restriction is introduced to the CV system, and an on-board-diagnostic system may detect high-crankcase pressure through existing crankcase pressure sensors and de-rate the internal combustion engine. In other arrangements, a spring-loaded mechanism within the shaft prevents a housing cover (e.g., a lid to the housing of the CV system) from being repositioned when a coalescing element is not installed within the housing.