Patent Application
20070036024
1. Field of the Invention
The present invention relates to a system for selectively blending and mixing fluids, such as cleaning fluid concentrates and a carrier fluid, such as water. The present system is ideally employed in a vehicle washing facility or other facility in which a variety of solutions must be blended and mixed in a relatively precise, yet cost effective manner.
2. Disclosure Information
Commercial cleaning establishments such as carwashes typically employ several cleaning solutions to economically treat various areas of a vehicle. For example, solutions used for cleaning the painted surfaces of a vehicle and wheel cleaning solutions usually have different concentrations, and even different base components. This arises from the fact that road grime clinging to a painted surface and disc brake dust will not necessarily respond optimally to the same cleaning solution.
Designers of commercial cleaning solution blending and mixing systems have employed a variety of configurations to provide solutions for carwashes. U.S. Pat. No. 5,439,020 discloses a detergent mixing apparatus and method in which reservoirs of various cleaning solution concentrates are manifolded together and drawn through a single eductor. The mixing ratios produced by the system of the '020 patent would be difficult to adjust because of cross-talk or interference between the competing concentrate fluid flows. U.S. Pat. No. 5,678,593 discloses a detergent mixing apparatus in which multiple eductors are used in parallel to blend washing solutions. Because each eductor is driven by a separate flow of carrier fluid, the mixing of the final solution must be carefully controlled to avoid stratification of the finished solution. Also, each of the individual carrier fluid flows must be carefully controlled to achieve and maintain a precise mixing ratio. This may necessitate the use of more expensive flow control valves. In addition, the fluids are not mixed completely until they have been ejected into a separate holding tank.
A system according to the present invention solves problems associated with prior blending and mixing systems by allowing precise, easily adjustable and controllable feeding and mixing of cleaning solution concentrates into a single carrier fluid stream.
According to one aspect of the present invention, a fluid blending and mixing system includes a carrier fluid inlet, a mixing passage connected with said fluid inlet, with said mixing passage having a central axis, and a plurality of discrete, individually controllable mixers located along the central axis of said mixing passage such that a plurality of concentrate fluids may be blended and mixed into a carrier fluid flowing through said mixing passage. Each of the individually controllable mixers is fed with a different concentrate fluid and each includes a venturi having an orifice-controlled concentrate port. An upstream venturi blends and mixes a first concentrate fluid with the carrier fluid. At least one downstream venturi blends and mixes a second concentrate fluid with the blended and mixed fluid flowing from the first venturi.
The ratio of the throat diameter of the downstream venturi to the throat diameter of the upstream venturi is generally in the range of 1.0 to 1.9, and more particularly in the range of 1.2 to 1.9.
According to another aspect of the present invention, each of said individually controllable mixers may include a venturi having a concentrate port controlled by an electronic controller, such as a microprocessor, microcontroller, other microprocessor controller or a programmable logic controller (PLC) powering an electrically operated valve. As an alternative, the electronic controller may control a mixing valve through which concentrate is being drawn by a pump.
According to another aspect of the present invention, a fluid blending and mixing system includes a dissolution tank for dissolving powered chemicals and for providing the resulting liquid to at least one controllable mixer. The dissolution tank includes at least a water inlet valve and a mechanical mixer, with both said inlet valve and said mechanical mixer preferably being controlled by a microprocessor controller.
A system according to the present invention transfers the blended and mixed fluid flowing from the mixing passage to either a receiving tank or to the inlet of a distribution pump which delivers the finished fluid to one or more points of usage.
According to another aspect of the present invention, the mixing passage may include at least a manifold connected with the inlet of a pump, and with the individually controllable mixers including more than one electrically operated valve, and with the pump and valves being controlled by a microprocessor controller.
According to another aspect of the present invention, a method for blending and mixing a plurality of concentrate fluids into a carrier fluid, includes at least the steps of introducing a carrier fluid into a mixing passage, followed by blending a first concentrate fluid into the flowing carrier fluid by providing the first concentrate fluid to an upstream mixing venturi located along said mixing passage. Finally, the method includes the step of blending a second concentrate fluid into the blended and mixed fluid flowing from the upsteam venturi by providing the second concentrate fluid to a downstream venturi which receives the fluid flowing from the upstream venturi, with the downstream venturi having a throat which is at least as large as the throat of the upstream venturi.
It is an advantage of a blending and mixing system according to the present invention that more than one concentrate fluid may be progressively blended and mixed into a carrier fluid flowing through a single mixing passage. This simplifies the architecture of a mixing system, while providing maximum flexibility to control the flow ratios of the concentrates being added.
It is a further advantage of a system according to the present invention that the ratios of the concentrates being added to the carrier fluid may be easily adjusted to accommodate changes in the condition of vehicles. For example, for extremely dirty vehicles, the concentration of washing agents may be increased, while preserving the possibility of greater economy in terms of less usage of chemicals and rinse water when vehicles are less heavily soiled.
These and additional embodiments are discussed in greater detail below. Numerous other advantages as well as features and objects of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.
The objects, features and advantages of the present invention will be more readily appreciated upon reference to the following disclosure when considered in conjunction with the accompanying drawings and examples which form a portion of the specification, wherein like reference numerals are used to identify identical components in the various diagrams, in which:
Figure (or FIG.) 1 is a logarithmic graphical diagram showing the empirical relationship between pressure ratio and venturi throat diameter ratio for a flow system including upstream and downstream venturis or eductors.
Figure (or FIG.) 2 is a schematic representation of an exemplary first embodiment of a fluid blending and mixing system according to the present invention.
Figure (or FIG.) 3 is a schematic representation of an exemplary second embodiment of a fluid blending and mixing system according to the present invention including electronically controlled valves controlling the flow of concentrate through multiple fluid mixers.
Figure (or FIG.) 4 is a schematic representation of an exemplary third embodiment of a fluid blending and mixing system according to the present invention and is similar to
Figure (or FIG.) 5 is a schematic representation of an exemplary fourth embodiment of the present invention having a controller which operates all of the fluid metering functions.
Figure (or FIG.) 6 is a perspective view illustrating an exemplary hardware configuration for the exemplary systems of
The present system uses two venturis located in series to mix and blend fluids. In accordance with the exemplary embodiments of the present invention, the ratio of the throat diameter, D2, of the downstream venturi, to the throat diameter, D1, of the upstream venturi may be calculated by using the following formula:
D2/D1=(P1/P2)1/n(C1E1/C2E2)2/n (1)
Where:
In accordance with the exemplary embodiments, the empirical relationships of
As shown in
Flow through upstream mixer 22 is controlled by at least two factors. The first of these is the size of bore 42 extending through connector 38 (
Returning to
After transiting mixing passage 18, the mixed and blended fluid is discharged into receiving or dilution tank 46. Then the fluid is discharged through outlet line 50 to one or more points of use.
The present system may be employed to make up any number of different diluted solutions, and the portion of system 10 having mixers 22a and 26a and the illustrated associated hardware are an example of this flexibility.
Dissolution tank 60 carries a common blending stock for the exemplary system illustrated in
Returning to
The exemplary embodiment of
In the exemplary embodiment of
The agitation action occurring inherently within pump 150 helps to assure uniform mixing of the blended fluid. Downstream from pump 150, the blended fluid is retained in tanks 156 and 158. Water for blending and for making up the solution within dissolution tank 60 is controlled by valves 100, 112, and 116. Precise control of the water flow is enabled by flow meter 155, which is connected with PLC 154.
The system of
Although the present invention has been described in connection with particular embodiments thereof, it is to be understood that various modifications, alterations, and adaptations may be made by those skilled in the art without departing from the spirit and scope of the invention set forth in the following claims. It is to be understood that no limitation with respect to the specific methods and apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.
