Gas cleaning apparatus

Claim 2

In apparatus for separating gas from particulate solid matter entrained therein and having a solids collection receptacle; a blower; means providing communication between the intake of said blower and said solids collection receptacle whereby to place the interior of said solids collection receptacle under relatively negative pressure; a hollow structure for receiving particulate solid matter for entrainment in a gas flow stream; first duct means affording communication of the blower discharge with said hollow structure; and second duct means affording communication of said solids collection receptacle with said hollow structure; said solids collection receptacle, said blower, said hollow structure and said first and second duct means providing a system for recirculation of gas in a flow path from said hollow structure through said second duct means, said solids collection receptacle, said blower and said fiRst duct means back to said hollow structure and continuously over said path, the intake of said blower, said solids collection receptacle, said second duct means and a part of said hollow structure being under said relatively negative pressure, whereby some gas in addition to the recirculated gas enters into said flow path from outside said system; the improvement comprising gas bleeding means for preventing said addition of gas from outside said system from undesirably increasing the average gas pressure in said system, said gas bleeding means including a pressure relief plenum; a bypass opening in said first duct means communicating with said pressure relief plenum; a gas bleed outlet in said plenum; and a valve in said plenum for variably controlling the flow of gas therethrough from said by-pass opening to and through said gas bleed outlet.

Claim 3

Apparatus according to claim 1 including a filter mounted to receive gas discharged through said gas bleed outlet.

Claim 4

Apparatus according to claim 2 including a port in said second duct means communicating with said plenum, said valve being operable for selectively placing said plenum respectively into communication with said by-pass opening in said first duct means and with said port in said second duct means, communication of said plenum with said port in said second duct means providing for reverse flow of gas through said filter to dislodge solid material therefrom and carry it entrained through said second duct means to said solids collection receptacle.

Claim 5

Apparatus according to claim 3 in which said filter comprises a foraminous bag into which gas is discharged through said gas bleed outlet.

Claim 6

Apparatus according to claim 1 in which said first duct means includes the casing of said blower, said by-pass opening being formed in said casing itself.

Claim 7

Apparatus according to claim 1 in which said plenum includes an outer cylindrical wall portion located to receive by-passed gas tangentially from said by-pass opening to establish a swirling movement of gas and entrained particulate solid matter in said plenum, said gas bleed outlet being at the central portion of said plenum; said apparatus further including a port in said second duct means communicating with said plenum at a zone spaced circumferentially from the tangential reception of by-passed gas by said plenum, said valve being selectively movable to two positions in one of which positions it establishes relatively free flow of gas from said by-pass opening into said plenum and substantially prevents free flow of by-pass gas from said plenum to said port, and in the other of which positions said valve substantially prevents flow of gas from said by-pass opening into said plenum and establishes relatively free flow of gas from said plenum to said port and thence to said second duct means and said solids collection receptacle.

Claim 8

Apparatus according to claim 6 including a foraminous bag filter mounted to receive gas discharged from said gas bleed outlet.

Claim 9

Apparatus according to claim 7 including means providing communication between said second duct means and the interior of said bag filter at a location spaced from said gas bleed outlet.

Claim 10

Apparatus according to claim 6 in which said valve comprises a segmental part substantially conforming to the shape of said outer cylindrical wall portion, and means mounting said valve to turn about the axis of said cylindrical wall portion and said segmental part.

Claim 11

Apparatus according to claim 9 in which, when said valve is in said one of said two positions, a portion of said segmental part mainly cuts off communication between said plenum and said port but an edge of said segmental portion is spaced slightly from said plenum wall to provide a skimmer slit through which particulate solids centrifugally concentrated adjacent the inner surface of said plenum wall by the swirling of the gas within the plenum are discharged together with a minor portion of the by-passed gas to said port and thence to said Second duct means and said solids collection receptacle, the major portion of the by-passed gas being discharged through said gas bleed outlet.

Claim 12

Apparatus according to claim 10 including a hollow filter for receiving by-passed gas discharged through said gas bleed outlet; and solids return means for conducting a portion only of the gas and solids delivered to said filter to said second duct means for return to said solids collection receptacle.

Claim 13

Apparatus according to claim 11 in which said filter extends downwardly from said gas bleed outlet, and in which said solids reutrn means is connected to the lower portion of said filter.

Claim 14

Apparatus according to claim 12 in which said solids return means communicates with said second duct means via said hollow structure.

Claim 15

Apparatus according to claim 1 including a vertical screen partition in said solids collection receptacle dividing the latter into two sections one of which communicates with the blower intake and the other of which communicates with said second duct means.

Claim 16

Apparatus according to claim 1 including a separation chamber having a curved wall in open communication with said collection receptacle; a blower inlet passage extending through a wall of said chamber to the blower intake; and a curved baffle in said chamber having one edge spaced relatively far from the adjacent chamber wal to provide relatively free flow of gas from said collection receptacle into said chamber for being swirled therein as it moves inwardly to said inlet passage, the opposite edge of said curved baffle being spaced from but relatively close to said chamber curved wall to provide a skimmer slit through which solid matter centrifugally concentrated in the outer portion of said chamber is returned to said collection receptacle.

Claim 17

Apparatus according to claim 15 in which said blower comprises an impeller rotatable about a horizontal axis, and in which said one edge of said curved baffle is spaced below the top of said separation chamber to provide the relatively free flow of gas from the upper portion of said collection receptacle into the upper portion of said separation chamber, and further in which said opposite edge of said curved baffle is at the lower portion of the separation chamber, whereby said skimmer slit is so located as to discharge into the lower portion of said collection receptacle.

Claim 18

In an air flow surface cleaning apparatus, a pick-up head mounted for movement in the direction of cleaning progress over and adjacent to the surface to be cleaned, said pick-up head including a pressure chamber; a suction chamber; an inclined partition between said chambers extending transversely of the direction of cleaning progress movement and having an inclined slit orifice for the discharge of high velocity blast air from said pressure chamber against said surface and into said suction chamber; and means at the ends of said slit orifice in the path of the high velocity blast air for directing blast air emerging from said slit orifice inwardly and away from the respectively adjacent ends of said suction chamber and toward the longitudinal center of said suction chamber.

Claim 19

In an air flow surface cleaning apparatus, a pick-up head mounted for movement in the direction of cleaning progress over and adjacent to the surface to be cleaned, said pick-up head including a pressure chamber; a suction chamber; an inclined partition between said chambers extending transversely of the direction of cleaning progress movement and having an inclined slit orifice for the discharge of high velocity blast air from said pressure chamber against said surface and into said suction chamber; and means at the ends of said slit orifice in the path of the high velocity blast air for directing blast air emerging from said slit orifice inwardly and away from the respectively adjacent ends of said suction chamber and toward the longitudinal center of said suction chamber.

Claim 20

Apparatus according to claim 17 in which said means at the ends of said slit orifice comprise spacers within said slit orifice.

Claim 21

Apparatus according to claim 17 in which said means at the ends of said slit orifice comprise members within said suction chamber at the opposite ends thereof and having horizontal webs with chamfered portions in the path of the blast air emerging from the ends of the slit orifice.

Claim 22

Apparatus according to claim 17 in which said pick-up head has a unitary top wall comprising a relatively high pressure chamber top wall part; a relatively low suction chamber top wall part; and an intervening step-down part.

Claim 23

Apparatus according to claim 20 in which said intervening step-down part is inclined at the same inclination as said inclined partition.

Claim 24

Apparatus according to claim 17 in wHich said pick-up head includes a horizontal wall forming the bottom of the pressure chamber and spaced above the level of the surface being cleaned, said horizontal wall having an inclined edge flange providing one side of said slit orifice.

Claim 25

In an air flow surface cleaning equipment, a mobile support; a pick-up head carried by said support and including a pressure chamber and a suction chamber; and apparatus for separating air from particulate solid matter picked up and entrained by air flowing in said pick-up head from said pressure chamber to said suction chamber, said apparatus being mounted on said mobile support and comprising a solids collection receptacle; a blower; means providing communication between the intake of said blower and said receptacle; first duct means affording communication of the blower discharge with said pick-up head pressure chamber; second duct means affording communication of said receptacle with said pick-up head suction chamber, said receptacle, said blower, said pressure chamber, said suction chamber and said first and second duct means providing a system for continuous recirculation of air in a flow path from said suction chamber through said second duct means, said receptacle, said blower and said first duct means to said pressure chamber and thence back to said suction chamber, the intake of said blower, said solids collection receptacle, said second duct means and said pick-up head suction chamber being under relatively negative pressure, said recirculation flow being accompanied by some air entering into said flow path from outside said system and being added to the recirculated air flowing in said flow path; a pressure relief plenum; a by-pass opening in said first duct means communicating with said pressure relief plenum; an air bleed outlet in said plenum; and a valve in said plenum for variably controlling the flow of air therethrough from said by-pass opening to and through said air bleed outlet.

Claim 26

In an air flow surface cleaning equipment, a mobile support; a pick-up head carried by said support and including a pressure chamber and a suction chamber; and apparatus for separating air from particulate solid matter picked up and entrained by air flowing in said pick-up head from said pressure chamber to said suction chamber, said apparatus being mounted on said mobile support and comprising a solids collection receptacle; a blower; means providing communication between the intake of said blower and said receptacle; first duct means affording communication of the blower discharge with said pick-up head pressure chamber; second duct means affording communication of said receptacle with said pick-up head suction chamber, said receptacle, said blower, said pressure chamber, said suction chamber and said first and second duct means providing a system for continuous recirculation of air in a flow path from said suction chamber through said second duct means, said receptacle, said blower and said first duct means to said pressure chamber and thence back to said suction chamber, the intake of said blower, said solids collection receptacle, said second duct means and said pick-up head suction chamber being under relatively negative pressure, said recirculation flow being accompanied by some air entering into said flow path from outside said system and being added to the recirculated air flowing in said flow path; a pressure relief plenum; a by-pass opening in said first duct means communicating with said pressure relief plenum; an air bleed outlet in said plenum; and a valve in said plenum for variably controlling the flow of air therethrough from said by-pass opening to and through said air bleed outlet.

Claim 27

Apparatus according to claim 23 including a filter mounted to receive air discharged thnough said air bleed outlet.

Claim 28

Apparatus according to claim 24 including a port in said second duct means communicating with said plenum, said valve being operable for selectively placing said plenum respectively into communication with said by-pass opening in said first duct means and with said port in said second duct means, communication of said plenum with said port in said second duct means providing for reverse flow of air through said filter to dislodge solid material therefrom and carry it entrained through said second duct means to said solids collection receptacle.

Claim 29

Apparatus according to claim 23 in which said first duct means includes the casing of said blower, said by-pass opening being formed in said casing itself.

Claim 30

Apparatus according to claim 23 in which said plenum includes an outer cylindrical wall portion located to receive by-passed air tangentially from said by-pass opening to establish a swirling movement of air and entrained particulate solid matter in said plenum, said air bleed outlet being at the central portion of said plenum; said apparatus further including a port in said second duct means communicating with said plenum at a zone spaced circumferentially from the tangential reception of by-passed air by said plenum, said valve being selectively movable to two positions in one of which positions it establishes relatively free flow of air from said by-pass opening into said plenum and substantially prevents free flow of by-pass air from said plenum to said port, and in the other of which positions said valve substantially prevents flow of air from said by-pass opening into said plenum and establishes relatively free flow of air from said plenum to said port and thence to said second duct means and said solids collection receptacle.

Claim 31

Apparatus according to claim 27 in which said valve comprises a segmental part substantially conforming to the shape of said outer cylindrical wall portion, and mEans mounting said valve to turn about the axis of said cylindrical wall portion and said segmental part.

Claim 32

Apparatus according to claim 8 in which, when said valve is in said one of said two positions, a portion of said segmental part mainly cuts off communication between said plenum and said port but an edge of said segmental portion is spaced slightly from said plenum wall to provide a skimmer slit through which particulate solids centrifugally concentrated adjacent the inner surface of said plenum wall by the swirling of the air within the plenum are discharged together with a minor portion of the by-passed air to said port and thence to said second duct means and said solids collection receptacle, the major portion of the by-passed air being discharged through said air bleed outlet.

Claim 33

Apparatus according to claim 29 including a hollow filter for receiving by-passed air discharged through said air bleed outlet; and solids return means for conducting a portion only of the air and solids delivered to said filter to said second duct means for return to said solids collection receptacle.

Claim 34

Apparatus according to claim 30 in which said filter extends downwardly from said air bleed outlet, and in which said solids return means is connected to the lower portion of said filter.

Claim 35

Apparatus according to claim 31 in which said solids return means communicates with said second duct means via said pick-up head suction chamber.

Claim 36

In apparatus for separating gas from particulate solid matter entrained therein and having a solids collection receptacle; a blower; means providing communication between the intake of said blower and said solids collection receptacle whereby to place the interior of said solids collection receptacle under relatively negative pressure; a hollow structure for receiving particulate solid matter for entrainment in a gas flow stream; first duct means affording communication of the blower discharge with said hollow structure; and second duct means affording communication of said solids collection receptacle with said hollow structure; said solids collection receptacle, said blower, said hollow structure and said first and second duct means providing a system for recirculation of gas in a flow path from said hollow structure through said second duct means, said solids collection receptacle, said blower and said first duct means back to said hollow structure and continuously over said path, the intake of said blower, said solids collection receptacle, said second duct means and a part of said hollow structure being under said relatively negative pressure, whereby some gas in addition to the recirculated gas enters into said flow path from outside said system; the improvement comprising gas bleeding means for preventing said addition of gas from outside said system from undesirably increasing the average gas pressure in said system, said gas bleeding means including a by-pass opening in said first duct means; a gas bleed outlet communicating with said by-pass opening; a filter mounted vertically to receive therein gas and any entrained particles discharged through said gas bleed outlet; and solids return means for conducting a portion of the gas and solids delivered to said filter from the bottom of said filter to said second duct means for return to said solids collection receptacle, said solids return means comprising a restricted gas passage for causing said portion of gas and solids to flow at a high velocity so as to entrain particles collecting at the bottom of said filter and conduct them to said second duct means.

Claim 37

In apparatus for separating gas from particulate solid matter entrained therein and having a solids collection receptacle; a blower; means providing communication between the intake of said blower and said solids collection receptacle whereby to place the interior of said solids collection receptacle under relatively negative pressure; a hollow structure for receiving particulate solid matter for entrainment in a gas flow stream; first duct means affording communication of the blower discharge with said hollow structure; and second duct means affording communication of said solids collection receptacle with said hollow structure; said solids collection receptacle, said blower, said hollow structure and said first and second duct means providing a system for recirculation of gas in a flow path from said hollow structure through said second duct means, said solids collection receptacle, said blower and said first duct means back to said hollow structure and continuously over said path, the intake of said blower, said solids collection receptacle, said second duct means and a part of said hollow structure being under said relatively negative pressure, whereby some gas in addition to the recirculated gas enters into said flow path from outside said system; the improvement comprising gas bleeding means for preventing said addition of gas from outside said system from undesirably increasing the average gas pressure in said system, said gas bleeding means including a by-pass opening in said first duct means; a gas bleed outlet communicating with said by-pass opening; a filter mounted vertically to receive therein gas and any entrained particles discharged through said gas bleed outlet; and solids return means for conducting a portion of the gas and solids delivered to said filter from the bottom of said filter to said second duct means for return to said solids collection receptacle, said solids return means comprising a restricted gas passage for causing said portion of gas and solids to flow at a high velocity so as to entrain particles collecting at the bottom of said filter and conduct them to said second duct means.