This application is a division of application Ser. No. 12/283,083 filed Sep. 9, 2008, which is a continuation-in-part of U.S. application Ser. No. 11/103,209 filed Apr. 11, 2005.
The present invention is directed to an apparatus and method for cleaning coils in HVAC installations including particularly the coils located in outdoor, rooftop and attic HVAC units and coils located where electricity is usually not available.
A typical HVAC installation for residential and commercial buildings includes an outdoor condenser unit having heat exchange coils, indoor evaporator units having heat exchange fin and coil combinations with water condensate collection trays and drain lines located in ductwork, and air handling components.
Outdoor condenser coils are arranged in banks at the outer periphery of a condenser unit and are cooled with ambient air drawn through the coils by an electric fan. In operation, the coils accumulate deposits of pollen, grass clippings, insects, and so forth carried by ambient air drawn through the coils. In addition, the outdoor condenser coils develop an oxidized film or coating that diminishes heat exchange efficiency and requires periodic removal by chemical cleaning of the coil surface.
For optimum operating efficiency of HVAC installations, heat transfer coils must be cleaned from time to time of such deposits and coatings that build-up in normal operation and by natural processes (i.e., oxidation) with passage of time. The present invention provides an apparatus and method especially suited for cleaning outdoor coils in an effective manner so as to remove accumulated deposits and coil films or coatings which are detrimental to HVAC operating efficiency. The invention may be used for a routine maintenance schedule that checks building operating costs by ensuring thermal efficiency and extending the useful operating life of HVAC installations.
The invention provides an apparatus containing all components and consumable cleaners including water and chemical for cleaning HVAC coils situated in tough to reach areas, and further provides a method for effectively cleaning such coils.
The apparatus of the present invention comprises a portable machine having integrated operating components for movement from site to site for cleaning outdoor HVAC coils. The invention enables a time and labor efficient and an effective maintenance program for cleaning HVAC components.
In a preferred embodiment of the invention, the coil cleaning apparatus is a carryall comprising a base for housing operating components, together with separate containers for cleaning water and cleaning chemical mounted atop the base. The operating components include an electrical system for battery power operation of a motor driven pump for pressurized delivery of a cleaning water and chemical mixture, a plumbing system for pressure and flow regulation of cleaning fluid mixture, and for delivering an adjustable water and chemical mixture for cleaning coils with an applicator wand. Interchangeable nozzles provide for selection of spray pattern and flow rate appropriate to cleaning and rinsing operations.
In preferred embodiment the carryall base defines a compartment for enclosing and positioning electric power components including a DC power supply storage battery, battery re-charger circuit, motor driven pump, operating switch, fluid intake to the pump, and exterior connections for applicator wand and nozzles.
In a modified embodiment of the invention, the coil cleaning apparatus comprises a tank for supporting operating components and defining separate containers for cleaning water and cleaning chemical. An electrical system provides for battery power operation of a motor driven pump for pressurized delivery of a cleaning water and chemical mixture, a plumbing system for pressure and flow regulation of cleaning fluids, and for delivering an adjustable water and chemical mixture for cleaning coils with an applicator wand. Interchangeable nozzles provide for selection of spray pattern and flow rate appropriate to cleaning and rinsing operations.
In modified embodiment the tank has an inner compartment defining a water container and an exterior chemical container secured to a sidewall of the tank.
The tank body is recessed to define a compartment accessible from outside the tank for locating electric power components including a DC power supply storage battery, battery re-charger circuit, motor driven pump, operating switch, fluid intake to the pump, and exterior connections for applicator wand and nozzles.
In both preferred and modified arrangement, the HVAC coil cleaning apparatus is readily carried into position for coil cleaning and is particularly useful for access to outdoor and attic coils where electric service is normally not available.
In accordance with the both preferred and modified apparatus and method of the invention, an applicator wand enables an inside-to-outside cleaning of HVAC coil banks against the outside-to-inside direction of airflow through unit coils in normal operation. In a typical rooftop HVAC condenser coil unit, heat transfer coils are mounted vertically in framework along the outer sides of the unit. A cooling fan is situated horizontally in the topside of the unit. The fan draws ambient air more or less horizontally through the vertical heat transfer coils and directs exhaust airflow upwardly from the unit. Airflow through the unit is exterior-to-interior-to-exterior. Applicants have observed that such cooling air flow draws debris (grass clippings, insects, etc) from exterior sources to lodge lightly at the exterior side of coils and fins so as to impede air flow and to reduce coil heat transfer efficiency by reducing effective surface area of the coils. If not removed debris over time degrades to a pumice that promotes rusting of metal components especially framework of condenser units.
The method of the present invention using a water base cleaning solution flowing inside-to-outside of condenser unit coils against exterior-to-interior air flow is effective to push and dislodge debris from the coils and fins. It is to be understood that cleaning solution applied in the same direction as air flow (i.e., exterior-to-interior) is far less effective for coil cleaning because the cleaning solution would tend to drive lightly lodged debris more firmly in the coils and fins, and not clean the coils at all.
Grille work in the top side of the unit allows for access to the interior surface of the coils by means of an applicator wand so that the entire coil surface is cleaned by directing cleaning solution through the coils and fins from interior-to-exterior of the HVAC unit. The result is a thorough cleaning of the coils and the HVAC units by driving debris out of the delicate coils fins without harming them. Use of an applicator wand in this way obviates the need for dismantling a condenser unit for access to coil interior surface.
The applicator wand comprises an elongate hollow rod fitted at its distal end with a nozzle for directing cleaning solution in an interior-to-exterior direction through the entire area of unit coils for dislodging debris accumulated in the coils.
The coil cleaning invention is described with particular reference to cleaning outdoor HVAC coils, however, it is to be understood that HVAC condenser coils in any remote location can be cleaned by the invention.
Specific examples are included in the following description for purposes of clarity, but various details can be changed within the scope of the present invention.
An object of the invention is to provide an apparatus and method for cleaning HVAC condenser coils.
Another object of the invention is to provide a compact, portable, self-contained apparatus for cleaning HVAC coils located in outdoor condenser units and anywhere electric service is not available.
Another object of the invention is to provide coil cleaning apparatus and method for routine maintenance of HVAC equipment coils so as to control operating costs by maintaining thermal efficiency and by extending the useful life of HVAC equipment installed in residential and commercial buildings.
Another object of the invention is to provide a method for effective cleaning of condenser unit coils by issuing an interior-to-exterior flow of cleaning solution through coils against inflowing cooling air so as to dislodge accumulated debris.
Another object of the invention is to provide an applicator wand enabling interior-to-exterior application of cleaning fluid through HVAC coils in units located outdoors.
Other and further objects of the invention will become apparent with an understanding of the following detailed description of the invention or upon employment of the invention in practice.
A preferred embodiment of the invention has been chosen for detailed description to enable those having ordinary skill in the art to which the invention pertains to readily understand how to construct and use the invention and is shown in the accompanying drawing in which:
Referring to
A second interior compartment in the form of an open recess 12h (
The rear portion of the base is fitted with several pockets or wells 12i-1 opening through the top wall and extending downwardly into the base housing for storing or holding operating parts or accessories of the apparatus including hose pocket 12i for holding a coiled hose 30 through which cleaning solution is delivered to a coil being cleaned; spray gun pocket 12j for spray gun 32; nozzle pockets 12k for holding several spray nozzles N selected according to desired spray pattern; and extension wand pockets 12l for holding a set of extension wands W used for varying length of an applicator wand used for directing cleaning solution through condenser coils as more fully detailed below.
Peripheral skirt 12c encircles the entire perimeter of base housing with a removable door panel 12g for access to the battery compartment. The skirt and base housing have a profile (or footprint) seen in
As shown in
The carryall further comprises water container 14 and cleaning chemical container 16 mounted side-by-side on top of the strength wall 12b which forms the bottom of each container. Each container has a fill neck defining fill opening closed by a twist on/off closure cap.
Water container 14 has front 14a, back 14b, side 14c-d, top 14e, and bottom 12b walls defining a watertight interior space of approximately three-gallon capacity for cleaning water filled through opening 14f in fill-neck 14g. The opening is covered by a threaded closure cap 14h. The water container is molded of robust plastic and is formed integral with the base housing.
As shown in
A generally vertical strength plate 18 occupies the space between containers and is integral with the container walls 14b and 16a. Strength plate side edges 18a-b follow the contour of and are integral with container shoulders 14i and 16e. Side edges 18a-b converge to define a strength plate top 18c as a connecting junction for one end of carry handle 20. Carry handle 20 has one end 20a integral with top 18c of the strength plate, and extends over top wall 14e of the water container with its other end 20b terminating in a junction of top wall 14e and fill neck 14g. A handgrip opening 22 is thus defined between handle and top wall, and is situated centrally of the carryall for balanced carrying of the apparatus with containers filled, and with operating components in normal locations.
A schematic diagram of the plumbing system appears in
Spare nozzles N of various spray patterns for the applicator wand are kept next to the adjusting dial.
In operation, the motor driven pump, which is located underneath strength wall 12b of water container, draws chemical/soap through metering valve 24 and through connector first port 26a, and draws water into connector second port 26b through water line 26c from water container 14. Pump suction line 34 passes through opening 14o in the water container and provides fluid flow into the pump. The pump delivers cleaning solution at approximately 0.5 gpm and up to approximately 120 psi in selected dilution.
Referring to
A cover plate 132 for securing a separate soap or chemical container 134 is affixed by suitable fasteners f to the front wall of the tank. The cover plate 132 includes a central panel 132a generally parallel to front wall 114, and side panels 132b-c angled toward front wall so defining an interior space between cover plate and front wall for receiving container 134 of about ounce capacity. The central panel includes a vertical slit 132d as a sight level indicator of the amount of soap or chemical in container 134. The cover plate also provides a holster 132e in the form of a cylindrical pocket for pistol grip spray nozzle 136 described more fully below.
One of the side panels 132c is fitted with a metering valve 140 and adjusting dial 140a for controlling the quantity of cleaning liquid from container 134 mixed with water from container 126 in a cleaning operation. The panel also retains several nozzles N for use in varying spray patterns including flat spray and pinpoint spray nozzles.
As shown in
Plumbing components and lines are shown in
The cleaning mixture discharged from the pump through line 156 enters spray hose 166 controlled by pistol grip valve 136a and fitted with an applicator wand 170 and 270 shown in
A preferred battery is 12 volt, 7-12 amp-hour, deep cycle, sealed lead acid. The battery charging system output through jack 15 is 12 v DC at 1 ampere taking 4-5 hours to charge a fully discharged battery. The charging unit can be left plugged in indefinitely without harming the battery. The electrical system is compact for placement within the both preferred and modified embodiments, packs sufficient power for use in cleaning multiple condenser coils without need for recharging, and provides for ease of recharging in a technician's work van when the apparatus is moved between work sites or overnight.
Applicator wand 170 (
Applicator wand 270 (
Applicator extension wands W (
The preferred and modified embodiments of the invention are fitted with a shoulder carry strap ST of flexible web material such as nylon seen in
A technician equipped with a preferred or modified apparatus according to the invention proceeds as follows in cleaning a coil bank:
1. supplying up to three gallons of water and up to approximately 55 fluid ounces of a cleaning fluid of either liquid soap or liquid chemical;
2. mixing a cleaning solution of either soap or chemical cleaning fluid with water in a water-to-cleaning fluid dilution ratio in a range of 4:1 to 60:1;
3. pressurizing the cleaning solution up to approximately 120 psi;
4. establishing a flow rate of up to approximately 0.5 gpm through an applicator wand;
5. applying the cleaning solution by the applicator wand to the interior surface of coil banks in a condenser unit in a direction of flow interior-to-exterior of the condenser unit directly against the exterior-to-interior flow of ambient air into the condenser coils banks to dislodge debris lodged in the exterior surface of the coil banks; and
6. applying a rinsing solution to the exterior surface of the coils to remove dislodged debris and residual cleaning solution.
With the apparatus and method of the invention, technicians may now clean coils from the inside forcing debris back out. A powerful spray drives cleaning solutions through delicate fins without harming them and thoroughly rinses coils. An aerated nozzle, one of accessory nozzles provided, creates thick foam that penetrates deep into coils. Both preferred and modified embodiments have unique portable design, robust construction, an interchangeable deep cycle 12v rechargeable battery, and copious fluid capacity with an adjustable soap/chemical and water flow rate. The apparatus and method are for use in tough to reach areas, are designed for a realistic HVAC service atmosphere, and can be continuously used where electricity is not available. The apparatus obviates the need to drag hoses as well as separate pump sprayers to a work site. The apparatus has extended reach for washing elevated coils, can clean coils in limited access areas, and by reason of unique applicator wands, obviates time consuming need for dismantling condenser units for interior access to coils. Finally, a technician is able to recharge the battery in a work vehicle.
Various changes may be made to the structure embodying the principles of the invention. At several places in the specification values are indicated as being approximate, which is to be understood as covering a range of 20% plus to 20% minus the value indicated. The foregoing embodiments are set forth in an illustrative and not in a limiting sense. The scope of the invention is defined by the claims appended hereto.
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