US 12,440,795 B2
Secondary filter element and filter system
Dennis Stark, Mauer (DE); and Sascha Roth, Schwegenheim (DE)
Assigned to MANN+HUMMEL GmbH, Ludwigsburg (DE)
Filed by Mann+Hummel GmbH, Ludwigsburg (DE)
Filed on Jul. 20, 2022, as Appl. No. 17/869,266.
Claims priority of application No. 102021118700.1 (DE), filed on Jul. 20, 2021.
Prior Publication US 2023/0028125 A1, Jan. 26, 2023
Int. Cl. B01D 46/00 (2022.01); B01D 39/16 (2006.01); B01D 46/48 (2006.01); B01D 46/71 (2022.01); F02M 35/02 (2006.01); F02M 35/024 (2006.01); F02M 35/08 (2006.01)
CPC B01D 46/71 (2022.01) [B01D 39/1692 (2013.01); B01D 46/48 (2013.01); B01D 2265/06 (2013.01); F02M 35/02 (2013.01); F02M 35/02466 (2013.01); F02M 35/08 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A filter system for filtering a gaseous fluid and for pressure pulse self-cleaning in an air filtration system, comprising:
a purging device configured for applying a back-washing cleaning pressure pulse; and
a secondary filter element, comprising:
a hollow cylinder-shaped central tube extending along and surrounding a longitudinal axis and having an open end,
wherein, adjacent to the open end on a circumference of the hollow cylinder-shaped central tube, a circumferentially closed region having an axial length is formed;
a filter medium arranged on and closing about a radially outer side of the hollow cylinder-shaped central tube, configured for the gaseous fluid to flow from a radially outer side of the filter medium to a radially inner side of the filter medium;
wherein the radially outer side of the filter medium is an inflow side of the filter medium and
the radially inner side of the filter medium is an outflow side of the filter medium; and
wherein the circumferentially closed region covers at least one impact point of the back-washing cleaning pressure pulse applied by the purging device to impact the circumferentially closed region, thereby reducing a risk of damage to the filter medium from the back-washing cleaning pressure pulse;
wherein the at least one impact point is arranged on the axial length of the circumferentially closed region between the filter medium and the open end of the hollow cylinder-shaped central tube;
wherein the purging device comprises a purging pipe having a cone shaped diffuser adjacent an outlet end of the purging pipe, the cone shaped diffuser is configured to direct the back-washing cleaning pressure pulse onto the at least one impact point arranged on the axial length of the circumferentially closed region; and
a support element arranged at and closing about the inflow side of the filter medium and having flow-through openings,
wherein the support element has a proportion of an open surface provided for the flow-through openings to a closed surface of at most 85%, such that the support element covers and closes off at least 15% of a flow area of the inflow side of the filter medium, supporting and stabilizing the filter medium against the back-washing cleaning pressure pulse applied by the purging device.