US20030217421A1 - Foam generating system with a substantially constant foam delivery rate - Google Patents
Foam generating system with a substantially constant foam delivery rate Download PDFInfo
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- US20030217421A1 US20030217421A1 US10/155,353 US15535302A US2003217421A1 US 20030217421 A1 US20030217421 A1 US 20030217421A1 US 15535302 A US15535302 A US 15535302A US 2003217421 A1 US2003217421 A1 US 2003217421A1
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- Prior art keywords
- foam
- liquid
- foam generator
- generator
- supply tank
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
- A47L11/00—Machines for cleaning floors, carpets, furniture, walls, or wall coverings
- A47L11/40—Parts or details of machines not provided for in groups A47L11/02 - A47L11/38, or not restricted to one of these groups, e.g. handles, arrangements of switches, skirts, buffers, levers
- A47L11/408—Means for supplying cleaning or surface treating agents
- A47L11/4086—Arrangements for steam generation
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
- A47L11/00—Machines for cleaning floors, carpets, furniture, walls, or wall coverings
- A47L11/34—Machines for treating carpets in position by liquid, foam, or vapour, e.g. by steam
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/235—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids for making foam
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/45—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads
- B01F25/452—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces
- B01F25/4524—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces the components being pressed through foam-like inserts or through a bed of loose bodies, e.g. balls
- B01F25/45241—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces the components being pressed through foam-like inserts or through a bed of loose bodies, e.g. balls through a bed of balls
Definitions
- the invention relates to a foam generating system, and in particular, to a foam generating system that delivers foam to a user appliance at a substantially constant foam delivery rate (expressed as weight of foam per unit time).
- U.S. Pat. No. 4,366,081 discloses a foam generating system having a mixing column containing a dual bed of steel wool-like material.
- a stream of pressurized water aspirates a liquid from a vented reservoir and conveys the same to the base of the column.
- Compressed air is supplied to the column through a separate pressurized line. The flow rates of both the air and the liquid are controlled by separate valves.
- U.S. Pat. Nos. 4,901,925 and 5,238,155 both to Blake disclose a single air supply that pressurizes a reservoir containing the liquid and forces the same toward the mixing chamber containing the porous media. In such a foam generating system care must be exercised to insure that the structural integrity of the liquid supply reservoir is sufficient to withstand the forces imposed by the pressurized air supply.
- foam detergent has been found especially useful for carpet cleaning.
- Foam application has been shown to provide good dispersion of the chemical cleaning agent into rugs and carpets, enabling effective cleaning with less liquid.
- foam-based cleaning apparatus of the prior art is somewhat unstable, in the sense that excessively heavy foam may be delivered at times, leading to higher material cost, longer drying times, and streaking. At other times lighter foam is delivered resulting in insufficient cleaning.
- U.S. Pat. No. 6,276,613 discloses a foaming system for a floor cleaning apparatus that utilizes a dual column foam generator and a single air supply that both pressurizes a liquid supply tank and supplies air to the foam generator.
- the dual columns of the foam generator are believed to be positionally sensitive, meaning that unless the columns are substantially aligned at the same elevation, gravity will affect the flow through one of the columns.
- the use of a pressurized tank system requires that the tank be structurally robust to prevent rupture. Limitations on tank pressure to conform to the structural capability of the tank may also limit the distance over which liquid may be efficiently supplied to the dual foam generating columns.
- a foam generating system that has a substantially constant foam delivery rate (expressed as weight of foam per unit time) regardless of the operating pressures at various points in the foam generating system. It is believed to be of further advantage to provide a foam generating system which does not utilize a dual column foam generator and which does not require pressurization of the liquid supply tank. Such a foam generating system is believed especially practical for use in connection with a carpet cleaning apparatus.
- the present invention is directed to a foam generating system including a foam generator having an inlet port and an outlet port, a source for supplying pressurized air at a predetermined air pressure to the inlet port of the foam generator, and a supply tank for carrying a liquid.
- the outlet port of the foam generator is connectible to a user appliance through a connection line having a predetermined pressure drop.
- the introduction of pressurized air and a liquid at the inlet port of the foam generator results in the delivery of foam at the outlet port thereof.
- the foam generator has a predetermined back pressure associated therewith.
- the foam generating system in accordance with the present invention is believed especially useful in a carpet cleaning apparatus with a carpet cleaning assembly as the user appliance connected to the outlet port of the foam generator.
- the foam generating system of the present invention is improved in that it includes a positive displacement pump operable at a constant liquid delivery rate for pumping liquid, such as a liquid cleaning agent, from the supply tank to the inlet port of the foam generator.
- the liquid delivery rate from the pump to the inlet port of the foam generator is independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the pressure drop of the connection line, and the volume of liquid in the supply tank.
- the supply tank is vented to atmosphere, avoiding the necessity of pressurizing the tank.
- the delivery rate of foam from the outlet port of the foam generator for delivery to the user appliance is substantially constant.
- FIG. 1 is a schematic diagram of a foam generating system of the present invention
- FIGS. 2A and 2B are respective side and front elevational views of the physical arrangement of the components of a foam generating system in accordance with the present invention in a “stand alone” configuration;
- FIGS. 3A through 3C are respective side elevational, rear elevational and plan views of a carpet cleaning apparatus incorporating a foam generating system in accordance with the present invention
- FIGS. 3D and 3E are side and front elevational views taken along the respective view lines in FIGS. 3C and 3A showing the physical arrangement of the components of a foam generating system in accordance with the present invention when used in a carpet cleaning apparatus.
- FIG. 1 shown is a schematic diagram of a foam generating system generally indicated by the reference character 10 in accordance with the present invention.
- the functional elements comprising the foam generating system 10 are illustrated as lying within the boundaries of the dot-dash line in the schematic rendition of FIG. 1.
- the form generating system 10 may be physically configured for “stand-alone” use as a source of foam to any user appliance (FIGS. 2A and 2B) or integrated within a carpet cleaning apparatus (FIGS. 3A through 3E).
- the foam generating system in accordance with the present invention may also be used in the environment of a fixed installation, such as the deposition of a foam agent (such as dye or other chemical agent) in a carpet manufacturing facility.
- a foam agent such as dye or other chemical agent
- the foam generating system 10 includes a foam generator 14 in the form of a column 14 C having an inlet port 14 I and an outlet port 14 P.
- the outlet port 14 P is provided with a suitable connection fitting 16 .
- a connection line L associated with a user appliance A may be detachably connected (via the fitting 16 ) to the output port 14 P of the foam generator foam generator 14 .
- the introduction of pressurized air and a liquid at the inlet port 14 I of the foam generator 14 results in the delivery of foam at the outlet port 14 P thereof.
- the foam generator 14 has a predetermined back pressure associated therewith.
- the connection line L between the foam generator 14 and the user appliance A also has a predetermined pressure drop associated therewith.
- foam generating apparatus 14 Any well-known form of foam generating apparatus 14 may be used in connection with the present invention, although a foam generating column 14 C in which glass beads 14 B (FIGS. 2A, 2B and FIGS. 3D, 3E) are used as the shearing medium is preferred.
- the glass bead column is inherently stable, requires no external devices or auxiliary action for foam generation, and provides uniform high quality foam. Changes in the diameter of the glass beads, the length of the column, the diameter of the column are not significant contributors to the resultant performance of the system.
- the foam generating column 14 C may be fabricated from commercially available hardware elements assembled to provide a container for the glass beads and the inlet for air and liquid.
- a cylinder may be formed from a length of tubing 14 T that is clamped (as by hose clamps 14 H) at each end to a pair of threadedly engaged fittings collectively shown at 14 F.
- Each of the outer fittings holds a screen retainer 14 R for the glass beads 14 B.
- the glass beads 14 B must be installed so that when the fittings 14 F are secured to the cylinder 14 T the beads 14 B are tightly packed. This precludes movement, channeling, and bypass of the flow that would defeat the shear action and foam generation.
- the foam generating system 10 includes a source 18 for supplying pressurized air at a predetermined air pressure to the inlet port 14 I of the foam generator 14 .
- the pressurized air source 18 may take the form of an air compressor 18 C such as that manufactured by Thomas Pump and Compressor, Sheboygan, Wis., and sold as model 639CE44.
- a filter 20 at the inlet of the pressurized air source 18 protects the system 10 from outside airborne contamination.
- the outlet of the pressurized air source 18 is connected to the inlet port 14 I of the foam generator 14 through a line 18 L.
- a flow control device 22 such as a fixed orifice available from Spraying Systems Company, Wheaton, Ill., as model CP 4916-054, is disposed in the line 18 L.
- the flow control device 22 establishes the ratio of air to liquid supplied to the inlet port 14 I of the foam generator 14 and thus determines the “blow ratio”, or wetness, of the foam.
- An adjustable orifice may be used if a further level of user control is desired.
- Liquid is supplied to the inlet port 14 I of the foam generator 14 by a positive displacement pump 24 through a line 24 L.
- the pump 24 draws liquid from a supply tank 28 that is connected to the inlet side of the pump 24 by a supply line 28 L.
- Suitable for use as the pump 24 is the positive displacement pump manufactured by Autoclude Pumps, Ltd., Essex, England, and sold as model M1500-4S-2225.
- a positive displacement pump is preferred because once the supply lines to the generator 14 are charged, the foam generator 14 operates essentially an “instant on” and “instant off” manner that is especially useful in portable equipment. Also, changing flow rate is accomplished by simply changing the pump speed.
- the supply tank 28 has a vent opening 28 V whereby the interior of the tank is vented to atmosphere.
- a vent opening 28 V By venting the tank 28 to atmosphere, the sometimes significant time delay required for a pressurized tank system to reach its operative pressurization level is avoided.
- a vented tank avoids the necessity for relieving tank pressure before flow ceases.
- the supply line 28 L is provided with a suitable fitting 30 (similar to the fitting 16 ) whereby the tank 28 may be connected and disconnected from the pump 24 . Since the tank 28 communicates with the suction side of the pump 24 the only limitation upon the distance at which the tank may be placed from the remainder of the system 10 is the “lift” or suction capability of the pump 24 .
- the system 10 is protected from liquid-borne contamination by a filter 34 .
- the filter 34 may be conveniently disposed in either the line 24 L (e.g., FIG. 2B) or the line 28 L (e.g., FIG. 3D), as desired.
- the tank 28 may be drained by pumping liquid through a drain line 36 L closed by a drain valve 36 V.
- the pump 24 is operable to deliver liquid to the inlet port 14 I of the foam generator 14 at a constant liquid delivery rate.
- the liquid delivery rate from the pump to the inlet port 14 I of the foam generator 14 is independent of the pressure of the air supplied by the pressurized air source 18 , the back pressure across the foam generator 14 , the volume of liquid in the supply tank 28 , and the pressure drop of the connection line L to the user appliance A.
- the delivery rate of foam from the outlet port 14 P of the foam generator 14 to the user appliance A is substantially constant.
- the term “substantially constant” in connection with either the liquid delivery rate to the foam generator or the foam delivery rate from the foam generator means that the weight of liquid or foam (in pounds or kilograms) per unit time does not vary substantially.
- system 10 of the present invention can be implemented in a mobile, cart-like “stand-alone” configuration.
- a typical implementation and the physical arrangement of the components of the foam generating system 10 in accordance with the present invention in a “stand alone” configuration is illustrated in FIGS. 2A and 2B.
- the supply tank 28 is mounted to a generally horizontal base portion 40 B of a generally L-shaped mounting bracket 40 .
- the remaining components of the system 10 are attached to the vertical leg 40 L of the cart 40 .
- the bracket 40 is itself attached to a frame 42 which supports axles 44 A and wheels 44 W.
- a handle 45 is attached to the vertical leg 40 L.
- the physical interconnection of the air and liquid supplies to the foam generator 14 is made using a T-fitting 46 .
- the air flow is introduced through the leg of the fitting 46 that aligns axially with the axis of the foam generating column 14 C, while liquid is introduced through the leg of the fitting 46 perpendicular thereto.
- FIGS. 3 A- 3 E The incorporation of the foam generating system 10 of the present invention into an apparatus for cleaning a carpet C may be understood from FIGS. 3 A- 3 E.
- FIGS. 3A through 3C Shown in FIGS. 3A through 3C is the basic structural elements of a carpet cleaning apparatus 50 , such as that cleaning apparatus described in U.S. Pat. No. 6,367,109 (Besel and Lee), assigned to assignee of the present invention.
- the apparatus 50 includes a frame 52 that supports a rotary carpet cleaning assembly 54 and the drive motor therefor (not shown).
- a handle projects 52H upwardly and rearwardly from the back edge of the frame 52 .
- the frame 52 also carries the axles 56 A for wheels 56 W.
- the carpet cleaning assembly 54 includes a plate 54 P that is rotationally mounted to the frame 52 .
- a brush 54 B is attached to the lower surface of the plate 54 P, while a frustoconical baffle 54 F is secured to the upper surface of the plate 54 P.
- the volume on the interior of the baffle communicates with the brush 54 B through foam supply passages 54 S.
- the carpet cleaning assembly 54 serves as the user appliance for the foam generated by the foam generator 14 .
- a housing 58 is mounted to the frame 52 .
- the interior of the housing 58 is hollow and defines a volume that serves as the supply tank 28 .
- the housing 58 is closed by a vented cap 58 C.
- lateral portions of the housing 58 extend rearwardly to define mounting wings 60 A, 60 B.
- the margin of each mounting wing 60 A, 60 B, as well as the rear margin of the housing 58 define mounting platforms 62 A, 62 B, 62 C, respectively.
- the components of the foam generating system 10 are mounted to a mounting plate 68 that takes the form of a “reverse 7 ”.
- the front and side edges of the top 68 T of the plate 68 are received on the mounting platforms 62 A, 62 B, 62 C and there secured by mounting bolts 70 .
- the lateral edges of the leg 68 L of the plate 68 are secured to the wings 60 A, 60 B, as by bolts 72 .
- FIGS. 3D and 3E The physical arrangement of the components of the foam generating system the surface of the leg 68 L of the plate 68 is best seen in FIGS. 3D and 3E.
- the outlet line L from the foam generator 14 is connected to the carpet cleaning assembly 54 (the user appliance in this implementation of the invention) through a pipe P (FIGS. 3A, 3B) that is attached to the frame 52 .
- Foam from the generator 14 enters to the volume on the interior of the baffle 54 F through a nozzle N (FIGS. 3A, 3B).
- the foam generating system 10 of the present invention is seen to provide significant advantages over foam delivery systems of the prior art. Owing to the use of the positive displacement pump the liquid and foam delivery rates are independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the volume of liquid in the supply tank, and the pressure drop of the connection line. This is a significant advantage when the foam generator is used to feed portable application equipment that requires a steady flow for uniform deposition of foam over relatively long distances (on the order of one hundred feet).
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Abstract
A foam generating system utilizes a positive displacement pump to deliver liquid at a substantially constant liquid delivery rate to a foam generator. The liquid delivery rate is independent the pressure of air supplied by a pressurized air source to the foam generator, the back pressure of the foam generator itself, the volume of liquid in a supply tank, and the pressure drop of the connection line from the foam generator to a user appliance. The foam generator delivers foam at a constant foam delivery rate (expressed as weight of foam per unit time) to the user appliance. The liquid supply tank is vented to atmosphere.
Description
- Field of the Invention The invention relates to a foam generating system, and in particular, to a foam generating system that delivers foam to a user appliance at a substantially constant foam delivery rate (expressed as weight of foam per unit time).
- Description of the Prior Art Systems for generating foam by combining pressurized air with a liquid (such as a liquid detergent) are well known. Such systems utilize various porous media to shear the supplied liquid and air to generate foam.
- U.S. Pat. No. 4,366,081 (Hull) discloses a foam generating system having a mixing column containing a dual bed of steel wool-like material. A stream of pressurized water aspirates a liquid from a vented reservoir and conveys the same to the base of the column. Compressed air is supplied to the column through a separate pressurized line. The flow rates of both the air and the liquid are controlled by separate valves.
- U.S. Pat. Nos. 4,901,925 and 5,238,155 (both to Blake) disclose a single air supply that pressurizes a reservoir containing the liquid and forces the same toward the mixing chamber containing the porous media. In such a foam generating system care must be exercised to insure that the structural integrity of the liquid supply reservoir is sufficient to withstand the forces imposed by the pressurized air supply.
- Commercial carpet cleaning apparatus typically involves the application of a liquid detergent to the carpet surface followed by a rubbing, scrubbing or brushing action imposed by a carpet cleaning assembly. In an extraction cleaning system the liquid and entrained or dissolved dirt are subsequently removed from the carpet by vacuum suction. In an encapsulation cleaning system the liquid cleaning agent is not immediately removed, but acts to encapsulate the dirt for subsequent removal by dry vacuum. In either case time is allotted to allow the carpet to “air dry” after the cleaning cycle before it is exposed to further traffic.
- Sufficient cleaning liquid must be applied to the carpet surface to properly dissolve and carry away dirt and soil. Complete dispersion of the cleaning liquid into and throughout the carpet tufts is required in order to clean the carpet thoroughly.
- While there must be sufficient cleaning liquid applied to clean the flooring material in question an excess of liquid is also undesirable. The application of excessive liquid makes it difficult for carpets to dry in a timely manner. This can be especially important where carpets must be cleaned and returned to service promptly, as in the hospitality industry.
- Another negative aspect of excessive liquid is that cleaning liquid may leave residual material on carpet fibers which will attract dirt and cause the carpet to appear matted and dirty soon after cleaning. While special cleaning formulations can somewhat mitigate this problem, such formulations are expensive, hence application of excessive amounts of liquid is costly.
- Owing to these deficiencies with liquid cleaning agents foam detergent has been found especially useful for carpet cleaning. Foam application has been shown to provide good dispersion of the chemical cleaning agent into rugs and carpets, enabling effective cleaning with less liquid. Unfortunately, foam-based cleaning apparatus of the prior art is somewhat unstable, in the sense that excessively heavy foam may be delivered at times, leading to higher material cost, longer drying times, and streaking. At other times lighter foam is delivered resulting in insufficient cleaning.
- U.S. Pat. No. 6,276,613 (Kramer) discloses a foaming system for a floor cleaning apparatus that utilizes a dual column foam generator and a single air supply that both pressurizes a liquid supply tank and supplies air to the foam generator. The dual columns of the foam generator are believed to be positionally sensitive, meaning that unless the columns are substantially aligned at the same elevation, gravity will affect the flow through one of the columns. In addition, the use of a pressurized tank system requires that the tank be structurally robust to prevent rupture. Limitations on tank pressure to conform to the structural capability of the tank may also limit the distance over which liquid may be efficiently supplied to the dual foam generating columns.
- In view of the foregoing it is believed advantageous to provide a foam generating system that has a substantially constant foam delivery rate (expressed as weight of foam per unit time) regardless of the operating pressures at various points in the foam generating system. It is believed to be of further advantage to provide a foam generating system which does not utilize a dual column foam generator and which does not require pressurization of the liquid supply tank. Such a foam generating system is believed especially practical for use in connection with a carpet cleaning apparatus.
- The present invention is directed to a foam generating system including a foam generator having an inlet port and an outlet port, a source for supplying pressurized air at a predetermined air pressure to the inlet port of the foam generator, and a supply tank for carrying a liquid. The outlet port of the foam generator is connectible to a user appliance through a connection line having a predetermined pressure drop. The introduction of pressurized air and a liquid at the inlet port of the foam generator results in the delivery of foam at the outlet port thereof. During operation the foam generator has a predetermined back pressure associated therewith. The foam generating system in accordance with the present invention is believed especially useful in a carpet cleaning apparatus with a carpet cleaning assembly as the user appliance connected to the outlet port of the foam generator.
- The foam generating system of the present invention is improved in that it includes a positive displacement pump operable at a constant liquid delivery rate for pumping liquid, such as a liquid cleaning agent, from the supply tank to the inlet port of the foam generator. The liquid delivery rate from the pump to the inlet port of the foam generator is independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the pressure drop of the connection line, and the volume of liquid in the supply tank.
- The supply tank is vented to atmosphere, avoiding the necessity of pressurizing the tank.
- With the foam generating system of the present invention the delivery rate of foam from the outlet port of the foam generator for delivery to the user appliance (expressed as weight of foam per unit time) is substantially constant.
- The invention will be more fully understood from the following detailed description, taken in connection with the accompanying drawings which form a part of this application, and in which:
- FIG. 1 is a schematic diagram of a foam generating system of the present invention;
- FIGS. 2A and 2B are respective side and front elevational views of the physical arrangement of the components of a foam generating system in accordance with the present invention in a “stand alone” configuration; and
- FIGS. 3A through 3C are respective side elevational, rear elevational and plan views of a carpet cleaning apparatus incorporating a foam generating system in accordance with the present invention, while FIGS. 3D and 3E are side and front elevational views taken along the respective view lines in FIGS. 3C and 3A showing the physical arrangement of the components of a foam generating system in accordance with the present invention when used in a carpet cleaning apparatus.
- Throughout the following detailed description similar reference numerals refer to similar elements in all Figures of the drawings.
- With reference to FIG. 1 shown is a schematic diagram of a foam generating system generally indicated by the
reference character 10 in accordance with the present invention. The functional elements comprising thefoam generating system 10 are illustrated as lying within the boundaries of the dot-dash line in the schematic rendition of FIG. 1. As is discussed herein theform generating system 10 may be physically configured for “stand-alone” use as a source of foam to any user appliance (FIGS. 2A and 2B) or integrated within a carpet cleaning apparatus (FIGS. 3A through 3E). It should also be appreciated, however, that the foam generating system in accordance with the present invention may also be used in the environment of a fixed installation, such as the deposition of a foam agent (such as dye or other chemical agent) in a carpet manufacturing facility. - Functionally, the
foam generating system 10 includes afoam generator 14 in the form of acolumn 14C having aninlet port 14I and anoutlet port 14P. Theoutlet port 14P is provided with a suitable connection fitting 16. A connection line L associated with a user appliance A may be detachably connected (via the fitting 16) to theoutput port 14P of the foamgenerator foam generator 14. The introduction of pressurized air and a liquid at theinlet port 14I of thefoam generator 14 results in the delivery of foam at theoutlet port 14P thereof. During operation thefoam generator 14 has a predetermined back pressure associated therewith. In use, the connection line L between thefoam generator 14 and the user appliance A also has a predetermined pressure drop associated therewith. - Any well-known form of
foam generating apparatus 14 may be used in connection with the present invention, although afoam generating column 14C in which glass beads 14B (FIGS. 2A, 2B and FIGS. 3D, 3E) are used as the shearing medium is preferred. The glass bead column is inherently stable, requires no external devices or auxiliary action for foam generation, and provides uniform high quality foam. Changes in the diameter of the glass beads, the length of the column, the diameter of the column are not significant contributors to the resultant performance of the system. - In practice, the
foam generating column 14C may be fabricated from commercially available hardware elements assembled to provide a container for the glass beads and the inlet for air and liquid. For example, as seen in FIGS. 2B and 3E, a cylinder may be formed from a length oftubing 14T that is clamped (as byhose clamps 14H) at each end to a pair of threadedly engaged fittings collectively shown at 14F. Each of the outer fittings holds ascreen retainer 14R for the glass beads 14B. The glass beads 14B must be installed so that when thefittings 14F are secured to thecylinder 14T the beads 14B are tightly packed. This precludes movement, channeling, and bypass of the flow that would defeat the shear action and foam generation. - The
foam generating system 10 includes asource 18 for supplying pressurized air at a predetermined air pressure to theinlet port 14I of thefoam generator 14. Thepressurized air source 18 may take the form of anair compressor 18C such as that manufactured by Thomas Pump and Compressor, Sheboygan, Wis., and sold as model 639CE44. Afilter 20 at the inlet of thepressurized air source 18 protects thesystem 10 from outside airborne contamination. The outlet of thepressurized air source 18 is connected to theinlet port 14I of thefoam generator 14 through aline 18L. - A
flow control device 22, such as a fixed orifice available from Spraying Systems Company, Wheaton, Ill., as model CP 4916-054, is disposed in theline 18L. Theflow control device 22 establishes the ratio of air to liquid supplied to theinlet port 14I of thefoam generator 14 and thus determines the “blow ratio”, or wetness, of the foam. An adjustable orifice may be used if a further level of user control is desired. - Liquid is supplied to the
inlet port 14I of thefoam generator 14 by apositive displacement pump 24 through aline 24L. Thepump 24 draws liquid from asupply tank 28 that is connected to the inlet side of thepump 24 by asupply line 28L. Suitable for use as thepump 24 is the positive displacement pump manufactured by Autoclude Pumps, Ltd., Essex, England, and sold as model M1500-4S-2225. A positive displacement pump is preferred because once the supply lines to thegenerator 14 are charged, thefoam generator 14 operates essentially an “instant on” and “instant off” manner that is especially useful in portable equipment. Also, changing flow rate is accomplished by simply changing the pump speed. - In accordance with the present invention the
supply tank 28 has avent opening 28V whereby the interior of the tank is vented to atmosphere. By venting thetank 28 to atmosphere, the sometimes significant time delay required for a pressurized tank system to reach its operative pressurization level is avoided. In addition, a vented tank avoids the necessity for relieving tank pressure before flow ceases. - Although forming part of the
foam generating system 10, in some instances it may be desired to physically separate thetank 28 from the remainder of the functional elements forming thesystem 10. To this end thesupply line 28L is provided with a suitable fitting 30 (similar to the fitting 16) whereby thetank 28 may be connected and disconnected from thepump 24. Since thetank 28 communicates with the suction side of thepump 24 the only limitation upon the distance at which the tank may be placed from the remainder of thesystem 10 is the “lift” or suction capability of thepump 24. - The
system 10 is protected from liquid-borne contamination by afilter 34. Thefilter 34 may be conveniently disposed in either theline 24L (e.g., FIG. 2B) or theline 28L (e.g., FIG. 3D), as desired. Thetank 28 may be drained by pumping liquid through a drain line 36L closed by adrain valve 36V. - In operation, owing to its positive displacement action whereby a fixed amount of liquid is transferred through the pump on each operational cycle, the
pump 24 is operable to deliver liquid to theinlet port 14I of thefoam generator 14 at a constant liquid delivery rate. The liquid delivery rate from the pump to theinlet port 14I of thefoam generator 14 is independent of the pressure of the air supplied by thepressurized air source 18, the back pressure across thefoam generator 14, the volume of liquid in thesupply tank 28, and the pressure drop of the connection line L to the user appliance A. As a result, the delivery rate of foam from theoutlet port 14P of thefoam generator 14 to the user appliance A (expressed as weight of foam per unit time) is substantially constant. - As used throughout this application (including the claims) the term “substantially constant” in connection with either the liquid delivery rate to the foam generator or the foam delivery rate from the foam generator means that the weight of liquid or foam (in pounds or kilograms) per unit time does not vary substantially.
- As noted, the
system 10 of the present invention can be implemented in a mobile, cart-like “stand-alone” configuration. A typical implementation and the physical arrangement of the components of thefoam generating system 10 in accordance with the present invention in a “stand alone” configuration is illustrated in FIGS. 2A and 2B. - In a “stand alone” configuration the
supply tank 28 is mounted to a generallyhorizontal base portion 40B of a generally L-shaped mountingbracket 40. The remaining components of thesystem 10 are attached to thevertical leg 40L of thecart 40. Thebracket 40 is itself attached to aframe 42 which supportsaxles 44A andwheels 44W. Ahandle 45 is attached to thevertical leg 40L. - As seen from FIG. 2B (and also in FIG. 3D) the physical interconnection of the air and liquid supplies to the
foam generator 14 is made using a T-fitting 46. In the arrangement illustrated the air flow is introduced through the leg of the fitting 46 that aligns axially with the axis of thefoam generating column 14C, while liquid is introduced through the leg of the fitting 46 perpendicular thereto. - The incorporation of the
foam generating system 10 of the present invention into an apparatus for cleaning a carpet C may be understood from FIGS. 3A-3E. - Shown in FIGS. 3A through 3C is the basic structural elements of a
carpet cleaning apparatus 50, such as that cleaning apparatus described in U.S. Pat. No. 6,367,109 (Besel and Lee), assigned to assignee of the present invention. Theapparatus 50 includes aframe 52 that supports a rotarycarpet cleaning assembly 54 and the drive motor therefor (not shown). Ahandle projects 52H upwardly and rearwardly from the back edge of theframe 52. Theframe 52 also carries theaxles 56A forwheels 56W. - The
carpet cleaning assembly 54 includes aplate 54P that is rotationally mounted to theframe 52. A brush 54B is attached to the lower surface of theplate 54P, while afrustoconical baffle 54F is secured to the upper surface of theplate 54P. The volume on the interior of the baffle communicates with the brush 54B throughfoam supply passages 54S. In the environment of thecarpet cleaning apparatus 50 thecarpet cleaning assembly 54 serves as the user appliance for the foam generated by thefoam generator 14. - A
housing 58 is mounted to theframe 52. The interior of thehousing 58 is hollow and defines a volume that serves as thesupply tank 28. Thehousing 58 is closed by a vented cap 58C. - As is best seen in FIG. 3C lateral portions of the
housing 58 extend rearwardly to define mountingwings 60A, 60B. The margin of each mountingwing 60A, 60B, as well as the rear margin of thehousing 58, define mountingplatforms - The components of the
foam generating system 10 are mounted to a mountingplate 68 that takes the form of a “reverse 7”. The front and side edges of the top 68T of theplate 68 are received on the mountingplatforms bolts 70. The lateral edges of the leg 68L of theplate 68 are secured to thewings 60A, 60B, as bybolts 72. - The physical arrangement of the components of the foam generating system the surface of the leg68L of the
plate 68 is best seen in FIGS. 3D and 3E. The outlet line L from thefoam generator 14 is connected to the carpet cleaning assembly 54 (the user appliance in this implementation of the invention) through a pipe P (FIGS. 3A, 3B) that is attached to theframe 52. Foam from thegenerator 14 enters to the volume on the interior of thebaffle 54F through a nozzle N (FIGS. 3A, 3B). - However implemented, the
foam generating system 10 of the present invention is seen to provide significant advantages over foam delivery systems of the prior art. Owing to the use of the positive displacement pump the liquid and foam delivery rates are independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the volume of liquid in the supply tank, and the pressure drop of the connection line. This is a significant advantage when the foam generator is used to feed portable application equipment that requires a steady flow for uniform deposition of foam over relatively long distances (on the order of one hundred feet). - Those skilled in the art, having the benefit of the teachings of the present invention, as hereinabove set forth, may effect numerous modifications thereto. It should be understood that all such modifications lie within the contemplation of the present invention as defined by the appended claims.
Claims (2)
1. A foam generating system for delivering foam for use in a user appliance, the foam generating system comprising:
a foam generator having an inlet port and an outlet port, the introduction of pressurized air and a liquid at the inlet port of the foam generator resulting in the delivery of foam at the outlet port thereof, during operation the foam generator having a predetermined back pressure associated therewith, the outlet port of the foam generator being connectable to a user appliance through a connection line having a predetermined pressure drop;
a source for supplying pressurized air at a predetermined air pressure to the inlet port of the foam generator; and
a supply tank for carrying a liquid; the improvement comprising:
a vent through which the supply tank is vented to atmosphere; and
a positive displacement pump operable at a constant liquid delivery rate for pumping liquid from the liquid supply tank to the inlet port of the foam generator, the liquid delivery rate from the pump to the inlet port of the foam generator being independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the volume of liquid in the supply tank, and the pressure drop of the connection line,
whereby the delivery rate of foam from the outlet port of the foam generator for delivery to the user appliance (expressed as weight of foam per unit time) is substantially constant.
2. A carpet cleaning apparatus comprising:
a frame with a carpet cleaning assembly mounted thereon; and
a foam generating system for delivering foam to the carpet cleaning assembly, the foam generating system comprising:
a foam generator having an inlet port and an outlet port, the outlet port of the foam generator being connected to the carpet cleaning assembly through a connection line having a predetermined pressure drop;
the introduction of pressurized air and a liquid cleaning agent at the inlet port of the foam generator resulting in the delivery of foam at the outlet port thereof, during operation the foam generator having a predetermined back pressure associated therewith,
a source for supplying pressurized air at a predetermined air pressure to the inlet port of the foam generator; and
a supply tank for carrying a liquid cleaning agent;
the improvement comprising:
a vent through which the supply tank is vented to atmosphere; and
a positive displacement pump operable at a constant liquid delivery rate for pumping liquid cleaning agent from the supply tank to the inlet port of the foam generator, the liquid cleaning agent delivery rate from the pump being independent of the pressure of the air supplied by the pressurized air source, the back pressure of the foam generator, the volume of liquid cleaning agent in the supply tank, and the pressure drop of the connection line,
whereby the delivery rate of foam from the outlet port of the foam generator for delivery to the carpet cleaning assembly (expressed as weight of foam per unit time) is substantially constant.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/155,353 US20030217421A1 (en) | 2002-05-23 | 2002-05-23 | Foam generating system with a substantially constant foam delivery rate |
PCT/US2003/002467 WO2003099094A1 (en) | 2002-05-23 | 2003-01-27 | Foam generating system with a substantially constant foam delivery rate |
AU2003219686A AU2003219686A1 (en) | 2002-05-23 | 2003-01-27 | Foam generating system with a substantially constant foam delivery rate |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/155,353 US20030217421A1 (en) | 2002-05-23 | 2002-05-23 | Foam generating system with a substantially constant foam delivery rate |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030217421A1 true US20030217421A1 (en) | 2003-11-27 |
Family
ID=29549046
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/155,353 Abandoned US20030217421A1 (en) | 2002-05-23 | 2002-05-23 | Foam generating system with a substantially constant foam delivery rate |
Country Status (3)
Country | Link |
---|---|
US (1) | US20030217421A1 (en) |
AU (1) | AU2003219686A1 (en) |
WO (1) | WO2003099094A1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2399738A (en) * | 2003-03-25 | 2004-09-29 | Hoover Co | Constant head device for a cleaning machine |
US20060185113A1 (en) * | 2005-02-22 | 2006-08-24 | Royal Appliance Manufacturing Company | High pressure extractor |
US20070192973A1 (en) * | 2006-02-17 | 2007-08-23 | Alto U.S. Inc. | Floor maintenance machine |
US20080271279A1 (en) * | 2007-05-04 | 2008-11-06 | Ecolab Inc. | Mobile foam producing unit |
US7588037B1 (en) * | 2004-10-15 | 2009-09-15 | Ratliff Thomas R | Apparatus and method for cleaning and decontaminating an air distribution system |
US20100301064A1 (en) * | 2007-12-03 | 2010-12-02 | Herbert John Munro | Mixing apparatus |
US8839661B2 (en) | 2010-10-26 | 2014-09-23 | Dow Global Technologies Llc | Direct quantitative colorimetric measurement of liquid foam |
CN108136347A (en) * | 2015-09-09 | 2018-06-08 | 清洗技术控股有限公司 | Foam maker |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0082465A1 (en) * | 1981-12-23 | 1983-06-29 | Ramisch Kleinewefers GmbH | Apparatus for feeding foam to a coating device |
CA2020451A1 (en) * | 1990-07-04 | 1992-01-05 | Donald A. Macdonald | Foam type carpet cleaner |
JP3105778B2 (en) * | 1995-10-23 | 2000-11-06 | 大淀小松株式会社 | Carpet cleaner and carpet cleaning method |
US6276613B1 (en) * | 1999-02-22 | 2001-08-21 | Alto Us, Inc. | Chemical foaming system for floor cleaning machine |
US6367109B1 (en) * | 2000-02-10 | 2002-04-09 | E. I. Du Pont De Nemours And Company | Floor cleaning apparatus having a floating brush |
-
2002
- 2002-05-23 US US10/155,353 patent/US20030217421A1/en not_active Abandoned
-
2003
- 2003-01-27 WO PCT/US2003/002467 patent/WO2003099094A1/en not_active Application Discontinuation
- 2003-01-27 AU AU2003219686A patent/AU2003219686A1/en not_active Abandoned
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2399738A (en) * | 2003-03-25 | 2004-09-29 | Hoover Co | Constant head device for a cleaning machine |
US20040187250A1 (en) * | 2003-03-25 | 2004-09-30 | Leonatti John A. | Constant head device for a cleaning machine |
GB2399738B (en) * | 2003-03-25 | 2006-05-10 | Hoover Co | Constant head device for a cleaning machine |
US7954200B2 (en) | 2003-03-25 | 2011-06-07 | The Hoover Company | Constant head device for a cleaning machine |
US7588037B1 (en) * | 2004-10-15 | 2009-09-15 | Ratliff Thomas R | Apparatus and method for cleaning and decontaminating an air distribution system |
US7887639B1 (en) | 2004-10-15 | 2011-02-15 | Ratliff Thomas R | Apparatus and method for cleaning and decontaminating an air distribution system |
US7617829B1 (en) | 2004-10-15 | 2009-11-17 | Ratliff Thomas R | Apparatus and method for cleaning and decontaminating an air distribution system |
US8769763B2 (en) | 2005-02-22 | 2014-07-08 | Techtronic Floor Care Technology Limited | High pressure extractor |
WO2006091509A3 (en) * | 2005-02-22 | 2006-12-21 | Royal Appliance Mfg | High pressure extractor |
WO2006091509A2 (en) * | 2005-02-22 | 2006-08-31 | Royal Appliance Mfg. Co. | High pressure extractor |
US20060185113A1 (en) * | 2005-02-22 | 2006-08-24 | Royal Appliance Manufacturing Company | High pressure extractor |
US20070192973A1 (en) * | 2006-02-17 | 2007-08-23 | Alto U.S. Inc. | Floor maintenance machine |
US8551262B2 (en) | 2006-02-17 | 2013-10-08 | Nilfisk-Advance, Inc. | Floor maintenance machine |
US7827645B2 (en) * | 2006-02-17 | 2010-11-09 | Alto U.S. Inc. | Floor maintenance machine |
US20090194178A1 (en) * | 2007-05-04 | 2009-08-06 | Ecolab Inc. | Mobile Foam Producing Unit |
US7959091B2 (en) | 2007-05-04 | 2011-06-14 | Ecolab Usa Inc. | Mobile foam producing unit |
US7516907B2 (en) | 2007-05-04 | 2009-04-14 | Ecolab Inc. | Mobile foam producing unit |
US20080271279A1 (en) * | 2007-05-04 | 2008-11-06 | Ecolab Inc. | Mobile foam producing unit |
US20100301064A1 (en) * | 2007-12-03 | 2010-12-02 | Herbert John Munro | Mixing apparatus |
US8839661B2 (en) | 2010-10-26 | 2014-09-23 | Dow Global Technologies Llc | Direct quantitative colorimetric measurement of liquid foam |
CN108136347A (en) * | 2015-09-09 | 2018-06-08 | 清洗技术控股有限公司 | Foam maker |
EP3347122B1 (en) * | 2015-09-09 | 2020-02-19 | WashTec Holding GmbH | Foam formation device |
US10814293B2 (en) | 2015-09-09 | 2020-10-27 | Washtec Holding Gmbh | Foam generator |
Also Published As
Publication number | Publication date |
---|---|
AU2003219686A1 (en) | 2003-12-12 |
WO2003099094A1 (en) | 2003-12-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BESEL, ARLEN DALE;REEL/FRAME:012921/0469 Effective date: 20020523 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |