# US 8,539,638 B2 · Filter and vacuum cleaner having such a filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,539,638 B2 - Document ID: US8539638B2 - Status: Granted - Kind: B2 - Application number: 13/094,869 - Filed: 2011-04-27 - Published: 2011-11-10 - Granted: 2013-09-24 - Earliest claimed: 2010-05-05 - Assignees: Miele & Cie. KG - Applicants: Andre Bertram; Seyfettin Kara; Monika Seifert; Stefan Tiekoetter; Cornelius Wolf - Inventors: Andre Bertram; Seyfettin Kara; Monika Seifert; Stefan Tiekoetter; Cornelius Wolf - Web page: https://patentgrep.com/patent/US8539638B2 ## CPC - A47L 9/19: Means for monitoring filtering operation - A47L 9/122: {flat} - A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08) ## Abstract A filter includes a filter medium, a filter inlet side, a filter outlet side and an indicator device. The indicator device is configured to be acted upon by air flow through the filter and is disposed adjacent to the filter medium and extends from the filter inlet side to the filter outlet side. The indicator device includes an air path starting from the filter inlet side, a viewing window covering the air path on the filter outlet side, and a flow-through usage indicator configured to receive filtered material and disposed in the air path and visible beneath the viewing window on the filter outlet side. ## Claims ### Claim 1 A filter comprising: a filter medium; a filter inlet side; a filter outlet side; an indicator device configured to be acted upon by air flow through the filter, the indicator device being disposed adjacent to the filter medium and extending from the filter inlet side to the filter outlet side, the indicator device including: a first air path starting from the filter inlet side, a viewing window covering the air path on the filter outlet side, and a flow-through usage indicator configured to receive filtered material, the flow-through usage indicator being disposed in the air path and being visible beneath the viewing window on the filter outlet side. ### Claim 2 (depends on 1) The filter recited in claim 1, wherein the filter is configured as a vacuum cleaner exhaust filter. ### Claim 3 (depends on 1) The filter recited in claim 1, wherein the viewing window is configured to deflect air flowing in the first air path through the usage indicator. ### Claim 4 (depends on 1) The filter recited in claim 1, wherein the first air path extends from the viewing window to the filter inlet side through the flow-through usage indicator. ### Claim 5 (depends on 4) The filter recited in claim 4, wherein in a region of the filter inlet side, a downstream end of the first air path includes a channel section disposed parallel to the filter inlet side. ### Claim 6 (depends on 1) The filter as recited in claim 1, wherein the first air path extends to the filter outlet side through the usage indicator. ### Claim 7 (depends on 1) The filter recited in claim 1, further comprising a second air path symmetric to the first air path. ### Claim 8 (depends on 7) The filter recited in claim 7, wherein the second air path includes an additional usage indicator and an additional viewing window. ### Claim 9 (depends on 7) The filter recited in claim 7, wherein the second air path shares the viewing window and usage indicator with the first air path. ### Claim 10 (depends on 7) The filter recited in claim 7, wherein a separating layer is disposed between the first and second air paths. ### Claim 11 (depends on 1) The filter recited in claim 1, wherein the viewing window includes a lens. ### Claim 12 A vacuum cleaner including a filter comprising: a filter medium; a filter inlet side; a filter outlet side; an indicator device configured to be acted upon by air flow through the filter, the indicator device being disposed adjacent to the filter medium and extending from the filter inlet side to the filter outlet side, the indicator device including: a first air path starting from the filter inlet side, a viewing window covering the air path on the filter outlet side, and a flow-through usage indicator configured to receive filtered material, the flow-through usage indicator being disposed in the air path and being visible beneath the viewing window on the filter outlet side. ### Claim 13 (depends on 12) The vacuum cleaner recited in claim 12, wherein the filter is configured as a vacuum cleaner exhaust filter. ### Claim 14 (depends on 12) The vacuum cleaner recited in claim 12, wherein the viewing window is configured to deflect air flowing in the first air path through the usage indicator. ### Claim 15 (depends on 12) The vacuum cleaner recited in claim 12, wherein the first air path extends from the viewing window to the filter inlet side through the flow-through usage indicator. ### Claim 16 (depends on 15) The vacuum cleaner recited in claim 15, wherein in a region of the filter inlet side, a downstream end of the first air path includes a channel section disposed parallel to the filter inlet side. ### Claim 17 (depends on 12) The vacuum cleaner as recited in claim 12, wherein the first air path extends to the filter outlet side through the usage indicator. ### Claim 18 (depends on 12) The vacuum cleaner recited in claim 12, wherein the indicator device of the filter includes a second air path symmetric to the first air path.