Patent Application
20070262180
This disclosure relates to powered pressure-washing systems as used, for example, for commercial and industrial cleaning applications.
A variety of pressure-washing systems are available to consumers and professionals for light-duty and household cleaning work. Most of these systems are relatively light in weight and are highly portable (movable about by hand). Although these light-weight “household” units are powered by dedicated gasoline or electrical motors, the size of the motor and pumping power deliverable by the motor are necessarily severely limited in the interest of keeping the systems highly portable.
Heavy-duty, industrial cleaning work typically requires pressure-washing systems having more capacity and power than can be produced by the typical household unit. To address these requirements, the industry has developed larger and more powerful pressure-washing systems that are still self-contained (powered by their own dedicated motors). However, due to their size and mass (and also the size and mass of any fuel tank associated with them), these systems are less conveniently portable and must be conveyed about on a large carrier vehicle such as a trailer, truck, or van. Another disadvantage of these systems is that they are still limited in the amount of power they can develop. For example, with gasoline-powered systems, the engine powering the system is often of a small, single- or twin-cylinder configuration such as may be found on a riding lawnmower. The smaller size of such an engine results in limited available power for driving the pump producing the pressurized flow of liquid from the pressure-washing system. Increasing the size of the motor to obtain more power adds further substantial mass to the system, making the system even less portable.
A few pressure-washing systems are available that are mounted directly to a carrier vehicle (truck or van) and obtain power from the carrier-vehicle's engine. Driving power for the pressure-washing system is obtained from the vehicle's engine by a complex modification of the vehicle and engine. Specifically, the engine is permanently modified to include a power take-off (PTO) such as provided on a farm tractor's engine. A shaft is extended from the PTO through the floor of the carrier vehicle and connected to a high-pressure liquid pump usually located inside but in the rear of the carrier vehicle. The PTO mechanism and connecting shaft adds substantial complexity and mass, requiring that the carrier vehicle be even larger, more powerful, and more massive.
Heating a high-pressure liquid as delivered from a pressure-washing system can increase the cleaning efficiency and effectiveness of the liquid. Usually, heat is generated by an integrated or stand-alone burner unit that burns diesel, kerosene, propane, or other suitable fuel. Heat from the burning fuel is delivered to the pressurized liquid, usually by passing the hot combustion gases and the pressurized liquid through a heat-exchanger. Unfortunately, it is very difficult to accommodate a burner unit safely and conveniently on a carrier vehicle, especially in any manner in which the burner unit (and pressure-washing system) is enclosed in the carrier vehicle.
Pressure-washing systems are disclosed that are mounted to, and that obtain operating power from, a motor vehicle (called a “carrier” vehicle or “host vehicle”). Specifically, the pressure-washing systems are configured to derive operational power (pumping power) from the engine of the carrier vehicle and are also configured to extract heat from the engine for heating liquid for discharge by the pressure-washing system. The pressure-washing systems are sufficiently compact and efficient to be installed in any of various motor vehicles, including motor vehicles regarded as “compact” and “sub-compact” in size. Thus, the subject pressure-washing systems can be conveyed to a remote job site by a small, fuel-efficient vehicle, in contrast to having to use a large van, truck, or trailer to transport the system.
An aspect of the disclosure is directed to mobile pressure-washing systems. A representative embodiment of such a system comprises a vehicle including an engine that is configured and used, when the engine is running, for propelling the vehicle. The engine comprises a driven member and produces heat when running. The system includes a pump that is in proximal relation to the engine and that is operably coupled to the driven member of the engine such that the driven member of the running engine operates the pump for pumping and pressurizing a pressure-washing liquid. A first hydraulic conduit connects an inlet of the pump to a source of the pressure-washing liquid. The system also includes a heat-exchanger that is coupled to the engine so as to obtain heat from the engine for transfer to the pressure-washing liquid. The heat-exchanger is hydraulically coupled to the pump such that the pump and heat-exchanger cooperatively produce pressurized heated liquid. The system also includes a discharge outlet that is hydraulically coupled to receive the pressurized heated liquid from the pump and heat-exchanger and to discharge the pressurized heated liquid for cleaning purposes.
The pump can be any commercially available pump device capable of urging pressurized flow of a liquid at a desired operating pressure and flow rate, while being powered by a vehicle engine. The pump is situated proximally to the engine and can be mounted to the engine. A mounting plate can be used to facilitate such mounting. Alternatively, for example, the pump can be mounted on a structure separate from but near the engine. The pump can be coupled to the driven member via at least one pulley and drive belt. Exemplary alternative coupling schemes include, but are not limited to, toothed gears and drive chain, and gear trains. Yet another coupling scheme is connection to a turbine that is rotated by the pressure of exhaust gases produced by the engine.
The heat-exchanger can be hydraulically coupled downstream of the pump so as to receive pressurized liquid from the pump. In such a scheme, the pump can be configured to pump only non-heated liquid.
If the engine includes a liquid-cooling system comprising a radiator connected to receive and cool hot coolant circulated through the engine, the heat-exchanger can be hydraulically coupled to receive the hot coolant from the engine and to transfer heat from the hot coolant to the pressure-washing liquid. In such a system the heat-exchanger can be hydraulically coupled to receive hot coolant from the engine and to deliver heat-exchanged coolant to the radiator.
The engine typically includes an exhaust conduit that conducts hot exhaust gases as the engine is running. In addition to the heat-exchanger configuration summarized above, the system can comprise a second heat-exchanger connected to the exhaust conduit so as to receive the hot exhaust gases and to transfer heat from the hot exhaust gases to the pressure-washing fluid. The heat-exchangers can be hydraulically connected to each other such that pressure-washing fluid flows through and obtains heat from both heat-exchangers before being discharged for pressure-washing purposes.
As an alternative to embodiments including two heat-exchangers, the system can include one heat-exchanger that is connected to the exhaust conduit of the engine so as to receive hot exhaust gases from the engine and to transfer heat from the hot exhaust gases to the pressure-washing fluid.
The heat-exchanger(s), by extracting and using waste heat produced by the engine, eliminate a need (under most situations) for a separate burner (requiring a separate fuel source) for heating the liquid.
The system can further comprise a selectively actuatable clutch coupling the driven member to the pump. The clutch can be, for example, a magnetic clutch, an electric clutch, or an electromagnetic clutch. A remote switch can be provided in a location convenient for the operator when turning the system on and off. I.e., the clutch allows the cleaning system to be engaged, and thus operated, only when use of the pressure-washing system is desired. Thus, the clutch can preserve pump longevity and conserve engine power, particularly when the vehicle and its engine are small.
The system can further comprise first and second hydraulic couplings, wherein the first hydraulic coupling is connected to the input of the pump and is connectable to a source of the pressure-washing liquid, and the second hydraulic coupling is connected to the discharge outlet. The first and second hydraulic couplings can be located in a utility bay of the carrier vehicle. The utility bay can be located, for example, in the trunk of the vehicle or, if the vehicle is a truck, in the bed of the truck. The utility bay can include a control used by the operator for engaging and disengaging the clutch.
Thus, lightweight, efficient, and easily transported pressure-washing systems are provided. The systems are easily adapted for use on smaller vehicles, such as compact passenger cars, allowing for better fuel efficiency and lower costs to the user.
The foregoing and additional features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
The disclosure below is directed to a representative embodiment that is not intended to be limiting in any way.
Turning first to
Alternatively to attaching the mounting plate 18 directly to the engine 16, the mounting plate can be mounted in the engine compartment of the vehicle 12 so as to be in proximal relationship to the engine as if the mounting plate were mounted to the engine. Since the mounting plate 18 in this embodiment provides a mounting for the pump 20 and heat-exchanger 22, a “proximal relationship” of the mounting plate to the engine is any position of the mounting plate allowing power transfer from the engine to the pump, as described below.
Further alternatively, the mounting plate 18 can be eliminated and the pump 20 (and heat-exchanger 22) mounted in the engine compartment of the vehicle 12 or in any other manner that places the pump 20 in proximal relationship to the engine. For example, the pump 20 and heat-exchanger 22 can be mounted on the side of the engine bay or on the “firewall” of the engine compartment of the vehicle if space permits.
The pump 20 can be any of various suitable hydraulic pumps as known in the art for use in pressure-washing applications. For example, the pump 20 can be any of various configurations as used on portable, stand-alone pressure-washing systems. The pump 20 is selected based on the particular cleaning applications for which the system 10 will be used, the particular compatibility of the pump with the power capabilities of the engine 16, and the available space in the vicinity of the engine where the pump can be mounted. The pump 20 includes an inlet 21 and an outlet 23.
In the depicted embodiment, the pump 20 comprises a shaft 24 to which is attached a pulley 26. An accessory pulley 28 is mounted to the engine 16, for example, tandemly to a fan-pulley or other driven-pulley of the engine. A drive belt 30 is mounted to the pulleys 26, 28 such that, as the accessory pulley 28 is rotated by running of the engine 16, corresponding rotational motion is imparted to the pulley 26 of the pump. Thus, the pump 20 is operably coupled to the engine 16. As an alternative with certain engine configurations, it is possible to couple the shaft 24 of the pump 20 directly to a “driven member” of the engine, such as but not limited to the shaft to which the accessory pulley 28 is connected. (As used herein, a “driven member” is a portion of the engine 16 that undergoes motion, usually rotational motion, whenever the engine is running.) As another alternative, the shaft 24 can be coupled to a driven member using one or more gears, as in a gear train, or using a combination of gears and pulleys, for example. As yet another alternative (not shown), the engine 16 can include a turbine or analogous device, as a “driven member,” wherein the turbine is rotated by flow of exhaust gases from the engine, and the turbine is operably coupled (e.g., by a gear train or the like, if required) to the shaft 24.
The drive belt 30 in the depicted embodiment is not limited to a reinforced elastomeric “belt” as commonly used with pulleys in engines; in certain embodiments the drive belt can be a chain belt or the like that is used with pulleys provided with drive teeth around their circumference.
Either the pulley 26 or the shaft 24 includes a clutch 32 that can be turned on and off to effect engagement and disengagement, respectively, of pump operation from the running of the engine 16. By way of example, the clutch 32 can be an electrically or magnetically engageable type similar to clutches used on automotive air-conditioning compressors. By de-actuating the clutch 32, an operator selectably disengages the delivery of drive force from the engine 16 to the pump 20 whenever the pressure-washing system 10 is not in use, thereby preventing unnecessary wear on the pump 20. Actuation of the clutch 32 causes delivery of drive force from the engine 16 to the pump 20 during running of the engine and use of the pump for pressure-washing.
In
Liquid to be pressurized for pressure-washing purposes enters the pump 20 via the inlet 21, which conducts the liquid from a source 60, described later below. As the pump operates, it pressurizes the liquid and expels the pressurized liquid via the outlet 23. As engine coolant is circulated through the heat-exchanger 22, pressurized liquid from the outlet 23 circulates through the heat-exchanger, where the pressurized liquid obtains heat from the engine coolant by thermal exchange. The heat-exchanger 22 can be any of various commercially available heat-exchanging units selected based on its compatibility with the particular cooling system of the vehicle's engine 16 (e.g., liquid-cooled or air-cooled) and on its compatibility with the operating pressures developed by the pump 20.
Although, in this embodiment, the heat-exchanger 22 is hydraulically coupled downstream of the pump 20, other embodiments are possible in which the heat-exchanger is coupled upstream of the pump.
From the heat-exchanger 22, the heated, pressurized liquid is delivered via a conduit 42 (e.g., a flexible hose capable of withstanding the heat and pressure of the liquid) to a utility bay 44 or other convenient location on the vehicle 12. For example, the utility bay 44 can be the trunk of the vehicle 12 or other compartment or region dedicated to use for pressure washing and, desirably, sufficiently commodious for storing hoses and other implements used in pressure-washing.
The utility bay 44 includes hydraulic couplings 46, 48 and a control switch 50. The control switch 50 is electrically connected to a battery 52 or other convenient power supply (e.g., the vehicle's battery) and to the clutch 32. Thus, by manipulating the control switch 50, an operator can selectively turn the clutch 32 on and off as desired. Turning on the clutch 32 as the engine 16 is running effectively turns on the pressure-washing system. The hydraulic coupling 46 is connected to the conduit 42 from the heat-exchanger 22. At the hydraulic coupling 46, an operator can connect (via a conduit 54 such as a reinforced rubber hose) a pressure-washing wand 56 or the like as known in the art. For this purpose, the hydraulic coupling 46 desirably has a “quick-release” configuration to allow ready connection and disconnection from the conduit 54 as desired. Furthermore, the hydraulic coupling 46 desirably prevents, when disconnected from the conduit 54, liquid from draining from the conduit 42. In any event, the hydraulic coupling 46 and conduit 54 allow delivery of heated, pressurized liquid from the heat-exchanger 22 to a location remote from the vehicle 12 for use in pressure-washing.
The hydraulic coupling 48 is connectable to a conduit 58 (e.g., a reinforced rubber hose) that supplies water or other suitable liquid to the pressure-washing system. The hydraulic coupling 48 desirably is a “quick-release” type of coupling, similar to the hydraulic coupling 46, described above. The conduit 58 is configured to connect to the particular type of liquid source 60 normally used, such as a water spigot at the job site.
The water spigot can be, for example, connected to a municipal water supply at the job site or connected to a tank of liquid situated at the job site. Alternatively, the conduit 58 can be connected to a liquid tank 62 carried on the vehicle 12. Thus, the supplied liquid is delivered via the conduit 58 and via a conduit 64 (extending from the hydraulic coupling 48 to the pump 20) to the pump 20. As the liquid passes through the pump 20, the liquid is pressurized for delivery to the heat-exchanger 22 and ultimately to the wand 56.
As can be appreciated from the foregoing, operation of the pressure-washing system requires that the vehicle's engine 16 be running. Adequate heating of the liquid would be best achieved if the engine were operating at its normal equilibrium running temperature. If desired, the engine 16 can be provided with a throttle 66 for regulating the operational speed of the engine during times when the pressure-washing system is in use. Normally, during use of the pressure-washing system, the engine is not being used for propelling the vehicle, but situations are envisioned in which pressure-washing could be performed as the vehicle is moving.
Turning now to
Further with respect to
As an alternative to the pump 20 being powered by the engine 16 of the vehicle 12, it is possible to power the pump using an electric motor powered by the electrical system of the vehicle. Such an electrical system typically would include the battery 52 and an alternator (not shown, but well-known in the motor-vehicle art) for charging the battery as the engine 16 is running.
Whereas
Using both heat-exchangers 22, 200 can be very effective in providing hot, pressurized liquid for pressure-washing when, for example, the liquid temperature obtainable using the heat-exchanger 22 alone is insufficient for the task at hand. In this exemplary embodiment pressurized liquid flowing in the conduit 42 from the heat-exchanger 22 (used as a “primary” heat-exchanger; see
If even more heat is needed than can be supplied by the hot exhaust gases from the engine, a burner 220 can be installed at a location inside the inlet 206, for example. The burner 220 is connected to, and configured to combust fuel supplied by, an external source 222 such as a propane source. Hot gases produced by the burner 222 combined with the hot exhaust gases from the engine 16 provide a large amount of heat that can be exchanged with the liquid flowing through the heating coils 204.
In an alternative configuration of the secondary heat-exchanger 200, the hot exhaust gases from the engine 16 simply pass straight through a chamber containing the heat-exchange coils 204. Such a configuration would likely pose a lower back-pressure to the flow of exhaust from the engine to the external environment than the configuration shown in
Whereas the invention is described above in connection with several representative embodiments, it is not limited to those embodiments. On the contrary, the invention is intended to encompass all modifications, alternatives, and equivalents as may be within the spirit and scope of the invention, as set forth in the appended claims.
