Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
2001-06-15
2004-01-13
Snider, Theresa T. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S320000, C015S340100
Reexamination Certificate
active
06675437
ABSTRACT:
BACKGROUND
1. Related Application
The present application is related to and claims priority to PCT Application Serial No. PCT US99/29770, International Filing Date of Dec. 15, 1999, and Priority Date of Dec. 17, 1998, which is incorporated herein by reference for all purposes.
2. The Field of the Invention
This invention relates to carpet cleaning generally, and more particularly to portable, self-contained pumping and heating systems for carpet cleaning. More particularly still, the invention relates to a cleaning system that uses heated cleaning solution where the heat is derived from secondary heat of a primary heat-generating engine, which also provides mechanical force used to deliver and remove the cleaning solution during cleaning.
3. The Background Art
Ever since carpets came into common use, people have wrestled with the difficulty of keeping them clean. Carpet, unlike other fabric in household use, is exposed to an enormous amount of foreign matter such as dirt, grass, leaves, sand, dust, mud, animal hair, and spilled food. The problem is compounded by both the permanent (e.g. wall-to-wall) installation of carpet and the length of fibers found in many carpets. Permanent (e.g. wall-to-wall) installation requires on-site cleaning. Bundles or yarns comprised of many fibers tend to capture or adhere to soiling, such as particulate matter. Conventional washing and cleaning processes remain ineffective.
“Hot-water extraction” methods have been developed to facilitate carpet-cleaning. Hot water may actually include liquid water; saturated, two-phase, steam and water droplets; or superheated steam. The latter is not commonly relied upon, since it is typically hotter than the distortion temperature of synthetic fibers. Moreover, the energy requirements for the phase change to steam simply cannot be met by most heating plants for the purpose.
According to these methods, water is heated, pressurized, supplemented with chemical cleaning additives and applied to carpet in order to dissolve or release soils and particulates and to suspend the resulting matter in the water (e.g. solvent, carrier, etc.). A “vacuum” system then extracts the dissolved soils, suspended particulates, and water out of the fibers. The water and air flows drawn by the vacuum system entrain the entire mixture, carrying it to a holding tank.
Because the majority of soiling in textiles is oil and acid based, textile cleaning machine operators rely on basic solutions for cleaning agents. Also, because temperature greatly affects the processes of dissolving and chemical reactions, the higher the temperature of a cleaning fluid, the more effective the cleaning process. The water should preferably be at about 210° F. at the carpet surface. When water is substantially cooler, machine operators compensate by increasing the pressure, chemical content, or quantity of the cleaning fluid, or some combination thereof.
Pressure translates to fluid velocity, which affects penetration of fiber bundles (yarns) by the fluid. Higher velocity fluid may also better strip soils from fibers mechanically. Mechanical agitation may improve rates of dissolving by a solvent, and may reduce boundary layers near fibers for improved chemical reaction.
Water-based carpet cleaning may apply or leave excess water standing in carpets, or retained by surface tension therein. Excess water tends to damage carpets by soaking into areas over time, causing over-wetting. Over-wetted textiles often show signs of reduced strength, mildew, and delamination, a process in which the carpet takes on a rippled appearance due to separation of primary and secondary backings.
Excessive concentrations of chemicals (typically alkaline) may increase reaction rates for dissolving or removing soils, by removing binding agents adhering them to carpets. However, increasing chemical concentrations creates a whole new series of problems. Alkaline chemicals may remove or discolor pigments in carpet, remove stain-resisting treatments, void manufacturers' warranties, and attack fibers, glues, or backing materials' structural integrity. Also, cleaning chemicals are known to leave residues that cause carpet to re-soil at an accelerated rate by adhering to soiling materials.
Increased cleaning fluid temperatures increase chemical reaction rates, allowing textile cleaners to decrease the concentration of chemicals, the fluid pressure, and the fluid quantity used in the cleaning process. If the temperature of the cleaning fluid is high enough, soils can be removed even without chemical additives, high fluid pressure, or large quantities of fluid. The result is still somewhat chemical in nature, since water is a “solvent” for many naturally occurring materials. Also, temperature can affect diffusion of water into a material to be dissolved, and diffusion of dissolved materials in a structure, just as with other chemical processes.
Increasing the cleaning fluid temperature may change the thermodynamics of the application and drying process. For example, if less time is required to apply a high-speed spray of droplets, less soaking can occur. Also, the thermodynamic quality of the water in a high pressure jet may be increased, providing increased steam to break up water into smaller droplets, and to augment the air flow moving away form the cleaned carpet yarns. Less water residence time, and smaller particle sizes for water droplets result in entrainment of more liquid in the vacuum drawn pickup line. Likewise, higher energy content, less water, and less residence time means faster drying time. Thus, the risk of de-lamination, mold growth, tensile strength loss, and other ill effects of moisture is reduced. Instead, carpet is left with low moisture and a more neutral pH.
For effective cleaning, cleaning fluid temperatures must not only be high, but consistent. Since the effectiveness of any hot-water extraction method depends greatly on the fluid temperature, an inconsistent fluid temperature results in a carpet that appears patchy because it is cleaner in some places than in others. In addition, temperatures in excess of 240° F. can permanently yield synthetic fibers, thereby causing fiber memory loss and ruining the pile texture of carpet.
Several different types of hot-water extraction systems have been developed in the carpet cleaning industry. “Portable” systems are moved into a building and transported from room to room by an operator. They typically use household electricity and water supplies to run motors and heaters needed to heat, apply, and remove water. As a result, they provide inferior cleaning temperatures, typically in the range of 80° to 120° F. at the carpet surface. Portable machines are notorious for excessive use of chemicals. High chemical concentrations are required to clean textiles because of comparatively low cleaning temperatures.
“Truck-mounted” textile cleaning equipment may be of an “integral” type, also known as “direct drive” type (dependent on the automotive power plant for energy), or of a “slide-in” type (standalone). Each has its own set of performance and maintenance problems.
Direct drive systems marketed today rely exclusively on heat extracted from the engine coolant (radiator water). The result is that the best heat exchangers and transfer times do not produce a maximum cleaning fluid temperature above 195° F. in the heat exchanger, which temperature is substantially reduced by the time fluid reaches a carpet surface.
Integrated, direct drive systems rely on the coolant of an internal combustion engine to provide heat to the cleaning fluid. They rely on the fan belts of the vehicle engine for mechanical power. Such systems can provide comparatively high vacuum power, but temperatures typically range from 100° to 170° F. at the carpet surface. Since they take energy from the coolant that passes through the vehicle radiator, they provide an inconsistent, and still too low fluid temperature at the carpet surface. A lot of energy is available from the engine coolant, but at a low thermodynamic availability.
The fan belt from a ty
Broadbent Berne S.
Kirton & McConkie
Snider Theresa T.
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