Patent Grant
8707510
1. Field of the Invention
This invention relates to wet extraction cleaners. In one of its aspects, the invention relates to a wet extraction cleaner with a centrifugal separator adapted to separate entrained liquid, foam, and debris from a working air flow during an extraction process. In another of its aspects, the invention relates to a wet extraction cleaner with a flexible architectural structure with a separate liquid separator and recovery tank. In another of its aspects, the invention relates to a wet extraction cleaner with a recovery tank that is easier to empty. In yet another of its aspects, the invention relates to a wet extraction cleaner with an air-liquid separator that minimizes foam generation of extracted fluid. In still another of its aspects, the invention relates to an extraction cleaner with a centrifugal air-liquid separator adapted to minimize the pressure drop between the working air inlet and exhaust outlet for more efficient extractor operation. In yet another of its aspects, the invention relates to a wet extraction cleaner with an air-liquid separator configured for mounting in a variety of locations on an extraction cleaning machine, including mounting to or near a fluid recovery tank, or alternatively mounted remotely from the recovery tank such as on an upright handle portion separated from the fluid recovery tank. In still another of its aspects, the invention relates to a wet extraction cleaner having a relatively low profile of an air-water separator and recovery tank.
2. Description of the Related Art
Extractors are well-known suction cleaning devices used for deep cleaning carpets and other fabric surfaces, such as upholstery. Most carpet extractors comprise a fluid delivery system and a fluid recovery system. The fluid delivery system typically includes one or more fluid supply tanks for storing a supply of cleaning fluid, a fluid distributor for applying the cleaning fluid to the surface to be cleaned, and a fluid supply conduit for delivering the cleaning fluid from the fluid supply tank to the fluid distributor. The fluid delivery system can optionally include valves and/or pump assemblies for mixing and/or pressurizing the fluid for application by the fluid distributor.
The fluid recovery system typically comprises a recovery tank assembly, a suction nozzle positioned at the surface to be cleaned and in fluid communication with the recovery tank via a working air conduit, and a suction source in fluid communication with the recovery tank. The recovery tank assembly typically comprises an air-liquid separator configured to separate entrained liquid from a working air flow to prevent liquid ingestion into the suction source. An example of an upright extractor having representative fluid delivery and fluid recovery systems is disclosed in U.S. Pat. No. 6,131,237 to Kasper et al., which is incorporated herein by reference in its entirety.
U.S. Pat. No. 7,293,324 to Chui et al. discloses a wet/dry vacuum cleaner with a centrifugal flow air-liquid separator that includes a liquid collection chamber integral with and below the cylindrical separator and a controller in the liquid collection chamber to stop operation of a suction source when the liquid level within a liquid collection chamber rises to a predetermined level. The separation chamber comprises a cylindrical housing having a tangential inlet and a cylindrical wall that guides the liquid-entrained air in a circular path around the internal perimeter of the cylindrical housing. An exhaust outlet conduit of the separation chamber extends upwardly from an upper end of the separation chamber and is in communication with a remote suction source. The cylindrical collection chamber is disposed below the separation chamber and further comprises a float assembly adapted to move vertically along the inside wall to actuate a microswitch that selectively disconnects power to a vacuum motor when the fluid in the collection chamber rises to a predetermined level.
U.S. Pat. No. 7,048,783 to Ponjican et al. discloses a centrifugal flow air-liquid separator for a wet/dry vacuum cleaner. The separator comprises a separation housing having an open bottom that forms a liquid and debris outlet and further includes an exhaust standpipe protruding from the top wall and defining a dry air exhaust conduit therethrough. The exhaust standpipe is fluidly connected to a suction source mounted on top of the separator. The separator further comprises an offset inlet that is tangentially disposed at an upper portion of the housing. The inlet further comprises a lead-in track that extends from the inlet and at least partially around the circumference of the separator chamber to guide the incoming air-liquid mixture in a downward spiraling flow path toward the separator outlet and into a fluid collection chamber.
U.S. Pat. No. 1,568,413 to Peebles discloses a centrifugal steam entrainment-trap separator comprising a conical casing with a vapor discharge pipe extending upwardly through the center of the bottom wall and configured for connection to a remote vacuum source. The separator further comprises a liquid discharge duct connected to the bottom wall of the separator casing. A tangential working air inlet pipe is positioned near the lower portion of the casing. The separator is said to separate liquid-foam mixtures commonly encountered during various industrial processes such as milk evaporation and plant tannin extraction. In use, a liquid and foam mixture is delivered to the separator at high velocity where a combination of the swirling action, gravity, and friction against the tapered casing walls effectively breaks up the foam bubbles and separates the liquid from the vapor. The separated liquid exits the separator through the liquid discharge duct protruding from the bottom wall while the exhaust air exits the separator via the vapor discharge pipe.
U.S. Patent Application Publication No. 2006/0156699 to Kim discloses a cyclonic separator for a dry vacuum cleaner having a tangential inlet disposed at a lower portion of the separator housing. An exhaust pipe protrudes upwardly through the center of the separator bottom wall and has an open top thereby forming an exhaust conduit that is fluidly connected to a remote suction source. A dirty air flow is introduced into the separator through the inlet and swirls along the inside wall of the separator housing. Debris is centrifugally separated from the air stream and deposited into a cylindrical collection chamber surrounding the separation chamber. Exhaust air flows downwardly through the exhaust pipe to a suction source.
U.S. Pat. No. 3,776,385 to Maciula et al. discloses a hydrocyclone for separating heavier liquids and solids from a lighter liquid medium. The hydrocyclone comprises an upright cylindrical portion and a tangential liquid inlet fluidly connected thereto through. The cylindrical portion is closed by a top having an outlet. A downwardly-tapering conical portion having an upper diameter slightly less than that of the cylindrical portion is positioned coaxially within the cylindrical portion to define an annular space between the conical portion and cylindrical portion. In operation, a mixture of two immiscible liquids with some solids is injected into the hydrocyclone, and separated by centrifugally forces by movement of the heavier liquids and some larger solid particles outwardly towards the cylindrical wall and downwardly through the annular space into an underflow pot. At the same time, remaining solids entrained in the lighter liquid are separated in the conical portion and exit though a vertical opening at the bottom thereof into the underflow pot. The lighter liquid medium then flows upwardly through the outlet.
Additional examples of hydrocyclone-type separators are disclosed by U.S. Pat. Nos. 1,737,680 to Pinkham; 4,175,036 to Frykhult; 4,308,134 to Lilleker et al.; 4,816,156 to Brombach et al.; and 6,024,874 to Lott.
According to the invention, an extraction cleaning apparatus adapted for movement across a surface to be cleaned comprises a fluid delivery system including a fluid distributor and a fluid supply fluidly connected thereto. The fluid distributor is adapted to deliver cleaning fluid from the fluid supply to the surface to be cleaned. A fluid recovery system comprises a suction nozzle positioned at the surface to be cleaned and having an outlet opening, a recovery tank adapted to collect liquid and debris and having an inlet, a suction source, and a centrifugal separator.
The centrifugal separator comprises a cylindrical housing defining a separation chamber and having a separator inlet fluidly positioned at a lower portion of the cylindrical housing and connected to the suction nozzle outlet opening to provide fluid communication between the separation chamber and the suction nozzle outlet. The cylindrical housing further comprises a separator liquid outlet and an exhaust stand pipe. The separator inlet and the separator liquid outlet are positioned at a lower portion of the cylindrical housing. The separator liquid outlet is spaced from the separator inlet and in fluid communication between the separation chamber and the recovery tank inlet. The bottom portion of the separation chamber has an air outlet for exhausting air from the separation chamber. The exhaust stand pipe is within the separation chamber in fluid communication with the air outlet and extends upwardly therefrom to an open upper end to exhaust air separated from liquid in the separation chamber. A suction source is in fluid communication with the suction nozzle and the cylindrical separator to draw air and liquid from the surface to be cleaned and to pass the same into the separation chamber.
Further according to the invention, a centrifugal separator comprises a cylindrical housing defining a separation chamber; a separator inlet fluidly adapted to be connected to a suction nozzle and positioned at a lower portion of the cylindrical housing; a separator liquid outlet in a lower portion of the cylindrical housing, spaced from the separator inlet and in fluid communication between the separation chamber and the recovery tank inlet; an air outlet in a bottom portion of the separation chamber for exhausting air from the separation chamber and an exhaust stand pipe within the separation chamber in fluid communication with the air outlet and extending upwardly therefrom to an open upper end to exhaust air separated from liquid in the separation chamber.
In one embodiment, the suction source is positioned downstream of the separation chamber so that the air/water mixture is drawn into the separation chamber. In another embodiment, the suction source is positioned upstream of the separation chamber so that the air/water mixture is passed into the separation chamber under pressure.
In another embodiment, the separator inlet includes a conduit that introduces the air and liquid into the separation chamber through a side wall thereof at a tangential angle to the separation chamber through an inlet opening that forms linear edge that is perpendicular to the tangential angle of the separator inlet and parallel to a central axis of the cylindrical housing. Preferably, the inlet opening is an axially elongated rectangular aperture wherein the long dimension of the opening is parallel to the central axis of the separation chamber. In addition, the height-to-width ratio of the cross-sectional dimensions of the axially elongated rectangular inlet aperture can be in the range of 2:1 to 50:1. Preferably, the height-to-width ratio of the cross-sectional dimensions of the axially elongated rectangular inlet aperture is in the range of 20:1 to 40:1 and most preferably is about 30:1.
Further, the liquid outlet can be formed by a rectangular opening in a side wall of the cylindrical housing. In addition, the liquid outlet can also formed by a conduit that extends from the cylindrical housing at a tangential angle to the separation chamber.
In a preferred embodiment, the separator inlet is positioned higher in the separation chamber than the liquid outlet. Further, the separator inlet can be positioned about 180° from the separator liquid outlet about the cylindrical housing.
In another embodiment, the outlet stand pipe is flared outwardly at the open upper end thereof. In addition, the separator inlet can be positioned below the flared upper end of the outlet stand pipe.
The centrifugal air-liquid separator is adapted to minimize the pressure drop between the working air inlet and exhaust outlet for more efficient extractor operation.
The centrifugal air-liquid separator is configured for mounting in a variety of locations on an extraction cleaning machine, including mounting to or near a fluid recovery tank, or alternatively mounted remotely from the recovery tank such as on an upright handle portion separated from the fluid recovery tank.
Still further according to the invention, a plurality of centrifugal separators can be arranged in series or parallel configurations, or a combination thereof.
In the drawings:
Referring to the drawings, and in particular to
The extractor 10 includes a fluid delivery system for storing cleaning fluid and delivering the cleaning fluid to the surface to be cleaned. The fluid delivery system comprises a fluid supply tank 22 for storing a supply of cleaning fluid, a fluid distributor 24 for applying the cleaning fluid to the surface to be cleaned, and a fluid supply conduit 26 for delivering the cleaning fluid from the fluid supply tank 22 to the fluid distributor 24. The fluid delivery system 16 can optionally include valves and/or pump assemblies (not shown) for mixing and/or pressurizing fluid to be applied through the fluid distributor 24. Optionally, the fluid delivery system can comprise a plurality of fluid supply tanks 22 to hold a variety of different cleaning or surface treatment fluids.
The extractor 10 further comprises a fluid recovery system for removing spent cleaning fluid and debris from the cleaning surface. The fluid recovery system comprises a suction nozzle 28 positioned at a surface to be cleaned and fluidly connected to an improved centrifugal separator 30 for separating entrained liquid, foam, and debris from a working air flow. The centrifugal separator 30 can be configured for mounting to the extraction cleaner 10 in a variety of different arrangements, including mounting the centrifugal separator 30 to the foot assembly 12 or to the handle assembly 14. The centrifugal separator 30 can comprise a single separator or, alternatively, a plurality of separators arranged in series, in parallel configurations, or a combination thereof. A recovery tank 32 is fluidly connected to the separator 30 for collecting the separated liquid and debris. A vacuum motor/fan assembly 34 has a fan inlet 35 that is fluidly connected to the separator 30 via an exhaust air conduit 36. The vacuum motor/fan assembly 34 further has a fan outlet 37 that exhausts air from the vacuum motor/fan assembly 34. The housing for the foot assembly has a vent 13 for venting air from the fan outlet 37 to the atmosphere. The components of the fluid delivery system and the fluid recovery system are supported by at least one of the foot assembly 12 and the handle assembly 14. A detailed description of these systems and other common extractor sub-systems and assemblies such as an agitation system, cleaning fluid mixing system, a vacuum motor/fan assembly, a fluid heater, and the like can be found in U.S. Pat. No. 6,131,237 to Kasper et al. and U.S. Patent Application Publication No. 2007/0226943 to Lenkiewicz et al. which both disclose representative extraction machines and are both incorporated herein by reference in their entirety. Various components that are not germane to this invention will not be described in detail herein.
Referring to
Now referring to
The separator inlet 54 shape can directly impact separation efficacy. Although liquid inlet cross-section shapes other than the vertically elongated rectangular inlet openings such as circular, oval, square, triangular, or other non-uniform or unsymmetrical arcuate shapes can be used, an inlet opening and conduit that introduces the air and liquid into the separation chamber at a tangential angle and forms linear edge that is perpendicular to the tangential angle of the separator inlet and parallel to a central axis of the cylindrical housing, as, for example, vertically elongated rectangular inlet openings, are much preferred because these openings tend to sheet the liquid along the inner surface of the cylindrical sidewall 46. In this process, the foamed liquid/detergent mixture travels smoothly along the inside surface of the cylindrical sidewall 46 for an extended period during which the foam bubbles collapse due to the friction along the sidewall. It has been found through experimentation that separation efficiency measurably improves with the vertically elongated rectangular inlet conduit and openings into the separation chamber 52 compared with a conventional round or oval inlet openings into the chamber 52. The height-to-width ratio of the cross-sectional dimensions of the vertically elongated rectangular inlet aperture and inlet conduit 54 can vary over a range and generally are in the range of 2:1 to 50:1, preferably in the range of 20:1 to 40:1 and most preferably is about 30:1.
Further, the cross-sectional area A of the separator inlet 54 can affect parameters such as rotational velocity V of the working air flow as well as the pressure drop ΔP across the separator 30. Generally, the working air flow created during the extraction process contains a mixture of entrained water, cleaning solution, foam bubbles, dirt and debris. The working air flow must reach a minimum rotational velocity V for effective centrifugal separation of the entrained liquid, foam, and dirt. When the minimum rotational velocity V is achieved, the working air flow swirls around the separation chamber 52. The rotational flow generates an inertial centrifugal force that acts on the dense entrained material, such as liquid and debris, forcing it outwardly against the cylindrical sidewall 46, thereby generating friction which can break up entrained foam bubbles and release any entrapped air. Gravitational force also acts on the mixture and pulls denser/heavier material downwardly towards the bottom of the separator 30. The entrained liquid and debris are thereby centrifugally separated from the working air flow. The rotational velocity V of the incoming working air flow is inversely related to the cross-sectional area A of the separator inlet 54 opening such that the rotational velocity V will increase as the separator inlet cross-sectional area A is reduced if all other variables remain constant. It should be noted, however, that excessive rotational velocity V can cause excessive turbulence within the separation chamber 52, which can increase foam generation and lead to undesirable separation problems. Accordingly, a separator inlet 54 design is configured to permit adequate rotational velocity of the working air flow in order to realize effective separation while simultaneously minimizing the likelihood of excessive turbulence and foam generation is desired. With the proper dimensional parameters, the foam is forced into a sheet of rotating liquid caused by the tangential inlet and thereby forced to become incorporated into the liquid stream.
The separator inlet cross-sectional area A is also inversely related to the pressure drop ΔP across the separator 30. The pressure drop ΔP across the separator 30 is the difference between the vacuum pressure at the separator outlet Poutlet and the vacuum pressure at the separator inlet Pinlet. Generally, if all other factors are held constant, as the separator inlet 54 size is reduced, a higher vacuum pressure is created at the outlet Poutlet, thereby increasing the pressure drop ΔP across the separator 30. Additional variables such as the size and shape of the separator exhaust can also affect the pressure drop. A minimal pressure drop across the separator 30 is desirable for ensuring efficient extractor operation. Excessive pressure drop can affect vacuum motor/fan selection and ultimately impact overall product cost and energy usage. Accordingly, it is desirable to design the separator inlet 54 to minimize the pressure drop, ΔP, while balancing fluid separation performance considerations.
A separator liquid outlet 56 protrudes tangentially, outwardly from the cylindrical sidewall 46 of the separator 30 at a lower portion thereof. The separator liquid outlet 56 comprises a rectangular cross-section conduit having elongate vertical sidewalls 65, a top wall 69, and a bottom wall 67. The liquid outlet 56 further comprises an outlet aperture 71 formed in the cylindrical sidewall 46. The bottom wall 67 of the separator liquid outlet 56 is preferably located co-planar with or below the bottom separator wall 50 to facilitate liquid drainage from the separation chamber 52. The separator liquid outlet 56 can originate from a location on the cylindrical sidewall 46 spaced from the separator inlet 54 such that inlet aperture 61 and outlet aperture 71 are diametrically opposed. Alternatively, the inlet and outlet apertures 61, 71 can be spaced within an angular range of 15-345° along the cylindrical sidewall 46. In another alternate configuration, the liquid outlet 56 can protrude downwardly from the bottom wall 50 of the separator 30. The separator liquid outlet 56 can further be configured for fluid connection to a fluid recovery tank 32 or to an intermediate fluid outlet conduit 57 that will be described in more detail hereinafter.
Referring now to
As shown in
Referring back to
The recovery tank 32 can further comprise a known automatic vacuum shut-off mechanism (not shown) that is actuated when the fluid level inside the recovery tank 32 reaches a predetermined maximum fill level. The shut-off mechanism (not shown) can prevent potential fluid ingestion into the vacuum motor/fan assembly 34 and can comprise a mechanical shut-off float as disclosed in previously referenced U.S. Pat. No. 6,131,237 to Kasper et al. Additional known shut-off means are contemplated such as those incorporating fluid probes, micro-switches, or the like and will not be disclosed in detail herein.
In operation, the extractor 10 is prepared for use by filling the fluid supply tank 22 with cleaning fluid. The extractor 10 is plugged into a power supply whereupon the vacuum motor/fan assembly 34 becomes energized, thus generating a working airflow through the fluid recovery system. Cleaning fluid is selectively delivered to the cleaning surface via the fluid delivery system while the extractor 10 is moved to and fro across the cleaning surface. The working air flows in through the nozzle inlet 38, which is positioned adjacent to or at the cleaning surface. The working air is entrained with water, foam, cleaning solution, and dirt and debris. The working air mixture flows through the nozzle outlet 40 and into a working air conduit 42, whereupon it is delivered to the centrifugal separator 30 through the tangentially positioned separator inlet 54. The working air mixture swirls around the outer portion of the separation chamber 52 as it enters from the inlet 54. While the mixture swirls around the separation chamber 52, centrifugal force acts on the liquid and dense debris, forcing it outwardly towards the cylindrical sidewall 46 while the less dense dry air moves inwardly towards the flared exhaust inlet 64 at the center of the separator 30. The vertically elongated rectangular inlet 54 tends to flatten out the working air mixture to maximize the contact of the mixture with the inner surface of the cylindrical sidewall 46. Friction between the working air mixture and the cylindrical sidewall 46 tends to brake up entrained foam bubbles, thereby releasing the entrapped air and precipitating the moisture against the inner surface of the cylindrical sidewall 46. Gravitational force pulls the dense liquid and debris downwardly to collect the liquid and debris. In addition, the high rotational velocity of working air around the outer perimeter of the flared inlet 64 reduces re-entrainment of liquid in the exhaust airflow. Dry exhaust air is thereby separated from the working air mixture and is drawn inwardly towards the flared exhaust inlet 64.
Upon reaching the flared exhaust inlet 64, the velocity of the dry exhaust air slows, thus making it less prone to re-entrain liquid or debris. The exhaust air is drawn through the exhaust stand pipe 58, to the exhaust outlet 66, through an exhaust conduit 36, and eventually through the vacuum motor/fan assembly 34, where the air is then exhausted into the atmosphere through the vent 13 in the foot assembly 12. The separated liquid and dirt slurry flows through the separator liquid outlet aperture 52, through the outlet 56, and into the recovery tank 32 through the fluid inlet port 82. Optionally, an intermediate conduit 57 or hose can be incorporated to fluidly connect the separator liquid outlet 56 to the fluid inlet port 82, thereby adapting to a plethora of architectural options with respect to the position of the separator 30 and recovery tank 32 on the foot 12, handle 14, or combination thereof. When the fluid level within the recovery tank 32 rises to a predetermined fill level, a shut-off mechanism (not shown) is actuated to close off the exhaust inlet 64 or turn off the motor to interrupt the working air flow in a known manner. After disconnecting the power supply to the device, a user can grasp the recovery tank 32 via the carry handle 86 and detach the fluid inlet port 82 from the separator liquid outlet 56. A user can then invert the recovery tank 32 to pour the separated liquid and dirt out of the fluid inlet port 82 prior to replacing the recovery tank onto one of the foot 12 or handle assembly 14 for repeated use.
Referring now to
While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit. Reasonable variation and modification are possible within the foregoing description and drawings without departing from the spirit of the invention which is defined in the appended claims.
This application claims the benefit of U.S. Provisional Patent Application No. 61/241,232, filed Sep. 10, 2009, which is incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1568413 | Peebles | Jan 1926 | A |
| 1737680 | Pinkham | Dec 1929 | A |
| 1798510 | Winslow et al. | Mar 1931 | A |
| 2846024 | Theodor | Aug 1958 | A |
| 3392418 | Schowalter | Jul 1968 | A |
| 4167798 | Klugle et al. | Sep 1979 | A |
| 4175036 | Frykhult | Nov 1979 | A |
| 4308134 | Lilleker et al. | Dec 1981 | A |
| 4393538 | Olson | Jul 1983 | A |
| 4816156 | Brombach et al. | Mar 1989 | A |
| 6024874 | Lott | Feb 2000 | A |
| 6131237 | Kasper et al. | Oct 2000 | A |
| 6381801 | Clemons, Sr. | May 2002 | B1 |
| 7048783 | Ponjican et al. | May 2006 | B2 |
| 7293324 | Chui et al. | Nov 2007 | B2 |
| 20060156699 | Kim | Jul 2006 | A1 |
| 20070067945 | Kasper et al. | Mar 2007 | A1 |
| 20070209340 | Conrad | Sep 2007 | A1 |
| 20070289267 | Makarov et al. | Dec 2007 | A1 |
| 20080216278 | Krebs et al. | Sep 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 199417717 | Aug 1994 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20110056044 A1 | Mar 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61241232 | Sep 2009 | US |
