# US 12,214,309 B2 · Passive dust filter for an inspection hatch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,214,309 B2 - Document ID: US12214309B2 - Status: Granted - Kind: B2 - Application number: 17/714,273 - Filed: 2022-04-06 - Published: 2022-10-06 - Granted: 2025-02-04 - Earliest claimed: 2021-04-06 - Assignees: Benetech, Inc. - Applicants: Benetech, Inc. - Inventors: Robert Huskisson - Web page: https://patentgrep.com/patent/US12214309B2 ## CPC - B01D 46/001: {Means for connecting filter housings to supports} - B01D 46/71: with pressurised gas, e.g. pulsed air - B01D 46/0005: {Mounting of filtering elements within casings, housings or frames (B01D46/2422 takes precedence)} - B01D 46/0049: {containing fixed gas displacement elements or cores} - B01D 46/0086: {Filter condition indicators} - B01D 46/04: Cleaning filters - B01D 46/24: Particle separators, e.g. dust precipitators, using rigid hollow filter bodies - B01D 46/442: {by measuring the concentration of particles} - B01D 46/446: {by pressure measuring} - B01D 46/521: {using folded, pleated material} - B01D 46/58: connected in parallel - B01D 47/06: Spray cleaning - B01D 46/2411: {Filter cartridges} - B01D 50/60: Combinations of devices covered by groups B01D46/00 and B01D47/00 - B01D 2273/30: Means for generating a circulation of a fluid in a filtration system, e.g. using a pump or a fan - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract The invention is directed to a passive dust filtering system for an inspection hatch of steel bulk storage vessel. The system includes a filter containment unit and an adaptor section for securing the unit to the storage vessel. The adaptor section includes a mounting flange having one or more magnetic switches to engage the storage vessel. A purge control system is used to periodically pulse air into filter elements in the filter containment unit to blow dust from the outside of the filter elements back into the vessel. ## Claims ### Claim 1 A passive dust filtering system for an inspection hatch comprising: a filter containment unit; an adapter section connected to the filter containment unit for attaching the filter containment unit to a hatch of a bulk storage vessel; a plurality of filter elements supported in the filter containment unit; and, an air purge system in the filter containment unit for removing dust from an outer surface of the filter elements. ### Claim 2 (depends on 1) The passive dust filtering system of claim 1 wherein the adapter section includes a mounting bracket. ### Claim 3 (depends on 2) The passive dust filtering system of claim 2 wherein the mounting bracket includes a mounting flange and a gasket to provide an airtight seal between the flange and the hatch. ### Claim 4 (depends on 2) The passive dust filtering system of claim 2 wherein the mounting bracket includes a first magnetic switch to secure the mounting bracket to the bulk storage vessel around the hatch. ### Claim 5 (depends on 1) The passive dust filtering system of claim 1 wherein the filter containment unit includes a clean air plenum above the plurality of filter elements and panel separating the clean air plenum from an interior of the bulk storage vessel. ### Claim 6 (depends on 5) The passive dust filtering system of claim 5 wherein each of the plurality of filter elements is a cylindrical filter having a hollow interior and an open end in communication with the clean air plenum. ### Claim 7 (depends on 5) The passive dust filtering system of claim 5 wherein the filter containment unit includes a clean air vent. ### Claim 8 (depends on 1) The passive dust filtering system of claim 1 wherein the air purge system includes a differential pressure switch configured to measure the pressure across the filter elements and a supply of compressed air configured to pulse air into an interior portion of each of the filter elements. ### Claim 9 (depends on 8) The passive dust filtering system of claim 8 further comprising a purge control circuit coupled to the differential pressure switch and to the supply of compressed air. ### Claim 10 (depends on 5) The passive dust filtering system of claim 5 wherein the filter containment unit includes a dust detection sensor in the clean air plenum. ### Claim 11 (depends on 10) The passive dust filtering system of claim 10 wherein the dust detection sensor is coupled to an alarm. ### Claim 12 (depends on 7) The passive dust filtering system of claim 7 wherein the filter containment unit includes a rectangular body portion and a top lid connected to the body portion by a hinge. ### Claim 13 (depends on 12) The passive dust filtering system of claim 12 wherein the filter containment unit includes a handle mounted to an exterior surface of the body portion. ### Claim 14 (depends on 9) The passive dust filtering system of claim 9 wherein the air purge system includes an air distribution manifold coupled to the supply of compressed air to enable pulsing air in each of the plurality of filter elements. ### Claim 15 (depends on 14) The passive dust filtering system of claim 14 wherein the distribution manifold includes a plurality of diaphragm valves. ### Claim 16 A portable passive dust filtering system for a hatch of bulk storage vessel comprising: a rectangular filter containment unit having a plurality of outer side walls and an interior chamber; an adapter section connected to a first end of the filter containment unit, the adapter section including a mounting flange configured to secure the filter containment unit to a hatch of the bulk storage vessel; a plurality of magnetic switch brackets connected to the mounting flange; and, a lid connected to a second end of the filter containment unit. ### Claim 17 (depends on 16) The portable passive dust filtering system of claim 16 further comprising a plurality of cylindrical filter elements mounted to a plate in the interior chamber of the filter containment unit wherein the plate and plurality of filters define a clean air plenum on a first side of the plate. ### Claim 18 (depends on 17) The portable passive dust filtering system of claim 17 further comprising an air purge system in the interior chamber of the filter containment unit having a supply of compressed air and a differential pressure switch. ### Claim 19 (depends on 16) The portable passive dust filtering system of claim 16 further comprising a first handle connected to an outer surface of one of the plurality of outer side walls. ### Claim 20 (depends on 17) The portable passive dust filtering system of claim 17 further comprising a dust detection sensor in the clean air plenum of the filter containment unit.