Truck wash automatic chemical ratio proportioning

A chemical ratio proportioning apparatus (100, 200) intended primarily for use in a wash bay (10) of a vehicle wash system. A gantry (14) and spray wands (18) are used for washing a vehicle (12). A quantity of solvent such as water (109) is provided under pressure from water pumps (104, 202). A chemical (114, 114a) is provided under pressure from chemical pumps (124, 206, 206a), mixed in correct proportion under control of a control unit (120) and flow sensors 112 and 118. The control unit controls metering devices such as a metering pump (124) and/or one or more proportioning solenoid valves (208, 208a) to control the quantity of chemical (114, 114a) entering the system.

TECHNICAL FIELD

The present invention relates to the field of combination mechanical and hydraulic systems, and more particularly to a method and apparatus for washing vehicles. The predominant current usage of the present inventive improved vehicle wash apparatus and method is in the washing of commercial trucks, wherein economy, efficiency and reliability are important considerations.

BACKGROUND ART

Truck and auto wash apparatus are generally well known in the art. A great variety of configurations have been and are being employed in the field. These vary from largely manually operated devices to nearly completely automated machines. Whether the washing fluids are applied to a vehicle by an automated gantry, or the like, or by a hand held wand, there must be some method or means for mixing chemicals, such as soaps, with the water. Such method or means should be accurate, economical and reliable.

There are several methods in use, all of which have some problem or another. One method is downstream injection, whereby the pressure of the water flow is reduced to a point that a venturi injector can be used. This is inefficient and difficult for the operator, since the operator has to constantly change the pressure at the gun. Another method is upstream injection. This is also a problem, since it takes so long for the chemical to get to the selected spray nozzles from the equipment room, thereby wasting time, chemicals, and water.

Another method which has been used is to separate the chemical from the high pressure water completely by providing chemical laden water in a separate supply line pressurized by an air driven pump. This works well, but the chemical and water must be premixed, which is time consuming and requires additional holding tanks. Furthermore, according to this particular prior art method, anytime the discharge valve is open the product flows, whether that is the intention or not.

It would be beneficial to have a method or apparatus whereby chemicals could readily be mixed with water in a vehicle wash system which would not waste chemicals and/or time, and which would be reliable and accurate in operation. However, to the inventor's knowledge, all prior art systems have suffered from one or more of the problems discussed previously herein.

SUMMARY

Accordingly, it is an object of the present invention to provide a vehicle wash apparatus wherein chemicals are mixed with water as needed without undue operator intervention.

It is still another object of the present invention to provide a method and apparatus for mixing chemicals with a solvent on a demand basis.

It is yet another object of the present invention to provide a method and apparatus whereby chemicals will be accurately mixed with solvents even as demand for the mixture varies.

It is still another object of the present invention to provide a method and apparatus which is inexpensive to manufacture, and reliable and economical in operation.

It is yet another object of the present invention to provide a method and apparatus whereby a desired chemical ratio is delivered to spray wands and/or gantries in a vehicle wash, regardless of the instant demand for total solution.

These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of modes of carrying out the invention, and the industrial applicability thereof, as described herein and as illustrated in the several figures of the drawing. The objects and advantages listed are not an exhaustive list of all possible advantages of the invention. Moreover, it will be possible to practice the invention even where one or more of the intended objects and/or advantages might be absent or not required in the application.

Further, those skilled in the art will recognize that various embodiments of the present invention may achieve one or more, but not necessarily all, of the above described objects and/or advantages. Accordingly, the listed objects are not essential elements of the present invention, and should not be construed as limitations.

Briefly, one embodiment of the present invention is a system for providing a water and chemical mixture to a plurality of wash wands using a separate air pump for each wand. In this example of the invention, each of the air pumps has its air supply controlled so that it is only activated when a wash is authorized and in operation. All of the wands in the facility draw chemical from a single mix source and the mix is done on the fly based on the flow of product needed for the number of wands in use. This is done by having the air pumps draw on a common manifold with mix in it. The amount of chemical injected into the mix is determined by demand. The demand is calculated by looking at the volume of water being drawn through a flow sensor. The correct ratio of chemical to water is provided by metering chemicals, according to the desired ratio and the demand, into the water stream. A precise metering pump delivers the chemical through another flow sensor. A control algorithm, called PID or proportional integer derivative, is used to maintain a balanced ratio regardless of flow. This gives tight control of the quantity of chemical product being used. Optionally, other variables, such as water temperature, need for extra product on dirtier vehicles, and the like, can be used for control.

Another example of the present invention is an application for providing a water and chemical mixture to a gantry of a car wash. In this equally preferred embodiment, water is delivered to the gantry under pressure and passes through a flow sensor. Chemical is similarly delivered to the gantry under pressure, directly to a plurality of infinitely variable proportioning solenoid valves (three chemical products and three valves in this example of the invention). On demand, when water flows, a proportioning solenoid valve is opened and the chemical volume passes through a flow sensor. An algorithm is used to enforce the chemical ratio in the outgoing water stream.

DETAILED DESCRIPTION

The invention is described with reference to the Figures, wherein like numbers represent the same or similar elements. While this invention is described in terms of modes for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the present invention. Therefore, the embodiments and variations of the invention described herein, and/or shown in the drawings, are presented by way of example only and are not limiting as to the scope of the invention. Unless otherwise specifically stated, individual aspects and components of the invention may be omitted or modified, or may have substituted therefore known equivalents, or as yet unknown substitutes such as may be developed in the future or such as may be found to be acceptable substitutes in the future. The invention may also be modified for a variety of applications while remaining within the spirit and scope of the claimed invention, since the range of potential applications is great, and since it is intended that the present invention be adaptable to many such variations.

FIG. 1is a diagrammatic side elevational view of a wash bay10, such as might employ the present invention. The wash bay10is intended for washing a vehicle12. A gantry14having thereon a plurality of nozzles16is designed to move past the vehicle12and selectively spray thereon water or a mixture of water and chemicals, such as soap. The gantry14depicted in the view ofFIG. 1is a simple example used herein only to illustrate the context in which the present invention might be used. In practice, it is anticipated that a great variety of types of gantries and/or apparatus for moving the gantries might be used with the present invention.

The wash bay10is also equipped with one or more hand held wands18(two are depicted in the example of FIG.1). As one familiar with conventional vehicle wash apparatus will recognize, water and/or a water chemical mixture is provided to each of the wands18via one or more flexible tubes20. It is relevant to the present invention that all, none, or some quantity therebetween of the provided wands18might be in use at any one time, thereby creating a variance in demand for the water and chemical mixture provided thereto.

It should be noted that the present inventive method and apparatus is not restricted to be used with a single wash bay10. Indeed, it is anticipated that the invention will be used in conjunction with multiple wash bays, wherein the variation of demand might be even greater and wherein the need for and desirability of the present inventive apparatus and method will be even greater.

An example of an inventive chemical ratio proportioning apparatus is depicted in a diagrammatic view inFIG. 2, and is designated therein by the general reference character100. The chemical ratio proportioning apparatus100has a plurality of the spray wands18. Each of the spray wands has a corresponding manual valve102for selectively turning on and shutting off flow through a corresponding tube20to the associated wand18. In the example described herein, the manual valve102is a ball valve located on the associated wand18.

In this example of the invention, each wand has an associated pump104for providing pressurized fluid to its associated wand18. The pumps104are air driven pumps deriving air from an air supply106. A plurality of air supply valves108(one per pump104) allow air to be selectively turned off and on to each of the pumps104. Optionally, the air supply valves108may be remotely shut off until and unless a vehicle wash operation is authorized. The pumps104may also optionally be demand driven such that each respective pump104does not run until its associated manual valve102is opened to allow flow through the associated wand18.

Water109is provided to the wands18from a water source110. The water source110may be an ordinary water source such as a city water supply or well. Optionally, the water source110can be a tank wherein recycled water is stored. A water flow sensor112determines the quantity of water109being provided to the wands18at any given time. A chemical114(such as soap) is drawn from a chemical storage tank116and the flow of the chemical114from the chemical storage tank116is measured by a chemical flow sensor118. Signal is provided from the chemical flow sensor118and the water flow sensor112to a control unit120. In this example of the invention, the control unit120is a personal computer equipped with input means for accepting the output signals from the flow sensors112and118, although it is within the scope of the invention that a dedicated or specialized controlling apparatus might be developed for the purpose. In the example of the invention specifically described herein, signal is provided from the flow sensors112and118via a field communication bus122type field bus, which will be familiar to one skilled in the art. However, it is entirely within the scope of the invention that another type of communications means such as TCP/IP over Ethernet might be employed for the purpose.

In the presently described example of the invention, a precise metering pump124meters the exact amount of chemical114to be added to the water109under the control of the control unit120. In this example of the invention, the control unit calculates the amount of chemical to be added based on a Proportional, Integral, Derivative (“PID”) algorithm. PID algorithms are used to automatically adjust a variable to hold a measurement (or process variable) at a preselected set point. One skilled in the art will recognize that the variable to be adjusted (in this case, the quantity of chemical114to be provided) is called the manipulated variable, which variable is usually the calculated output of the controller120. The output of PID controller devices and algorithms changes in response to a change in either measurement (the flow of water109as measured by the water flow sensor112) or in the set point (the desired chemical/water ratio, as input by an operator).

FIG. 2also shows a diagrammatic representation of a level sensor126in the chemical storage tank116. The level sensor provides a signal to the control unit120to allow monitoring of the level of the chemical114in the chemical storage tank116.

As can be appreciated in light of the above description, according to this embodiment of the present inventive chemical ratio proportioning apparatus100, all of the spray wands18draw from a single mix manifold128wherein the water109and chemical114are mixed as described previously herein. As described, the quantity of chemical114provided (to maintain the desired proportion of chemical114to water109) is dependant upon the quantity of water109being used, which will in turn be dependant upon the number of spray wands18and/or gantry spray heads (not shown) in use. Optionally, the proportion of chemical114to water109can also be varied by the control unit120according to other variables, such as water temperature, special need (such as an especially dirty vehicle), or the like.

It should be noted that a variety of chemicals (not shown) could be selectively provided to each of the spray wands18by replicating the apparatus described above such that each of the spray wands18would have a plurality (one for each different chemical required) of manual valves102thereon for controlling the flow of each separate chemical. Also, it should be noted that it is anticipated that each of the spray wands18will have a separate high pressure water hose affixed thereto for delivering high pressure water without chemical. The high pressure water is controlled by a trigger type valve, in the manner of a conventional manual car wash wand. Since the high pressure water delivery system is well known in the art and is not a part of the presently described invention, it is omitted from the drawings in order to avoid making the drawings unnecessarily complicated.

FIG. 3is a diagrammatic representation of an equally preferred alternate embodiment200of the inventive chemical ratio proportioning apparatus. As can be seen in the view ofFIG. 3, the alternate embodiment200is configured for operation with a wash gantry14. It should be noted, however, that it is conceivable that the first described embodiment100could be used in conjunction with one or more gantries14, or the like. Similarly, this second described embodiment200could conceivably be used in conjunction with spray wands18(FIGS.1and2), or the like. Further, either embodiment can be used with a single gantry having a plurality of independently operating spray heads, to provide the correct amount of chemical116,116adepending on the number of spray heads in operation at any given time.

In the alternate embodiment of the invention, water109is delivered to the gantry14from the water source110under pressure provided by a water pump202. The flow of water109from the water source110is measured by a water flow sensor204(similar to the water flow sensor112in the example of FIG.2). Likewise, chemical114is delivered to the gantry14from the chemical storage tank116under pressure from a chemical pump206. Unlike the metering pump124(FIG. 2) discussed above in relation to the first described embodiment100of the invention, it is not necessary that the chemical pump206be a precision metering pump. An infinitely variable proportioning solenoid valve208meters the flow of the chemical114to the gantry14.

As described previously herein in relation to the first preferred embodiment100of the invention, the control unit120takes signal from the water flow sensor204and a chemical flow sensor210(similar to the chemical flow sensor118of FIG.2). Also similar to the operation of the first described embodiment100of the invention, the control unit uses an algorithm to enforce the chemical ratio to the gantry14in the presently described embodiment200of the invention. According to such algorithm, a desired ratio is achieved and maintained by the solenoid valve208under control of the control unit120. For example, where a ratio of 80 to 1 is desired, and where incoming water109is measured to be 20 gallons per minute (“gpm”), then the solenoid valve208is opened and chemical114is allowed to flow until the chemical flow sensor210indicates that the chemical114is flowing at the rate of 1 quart per minute, and the flow of the chemical114is then held at that rate. Optionally, software might be written to allow the control unit120to “learn” such that successive operations of the alternate chemical ratio proportioning apparatus200will allow the control unit120to determine the general orifice size (setting) for the solenoid valve208for different desired ratios of chemical flow, thereby saving even more time and chemical114. Also as discussed in relation to the first described embodiment100of the invention, the level sensor126provides input to the control unit120for monitoring the level of the chemical114in the chemical storage tank116.

As can be seen in the view ofFIG. 3, the chemical114is delivered through a chemical pipe240to a water pipe. In the example of the invention described in relation toFIG. 3, an injector244is used to inject the chemical114into the water pipe240. The injector244is a conventional component which uses venturi action to draw the chemical114into the water pipe240. It is conceivable that the injector244might be eliminated if the pressure provided by the chemical flow pump206were sufficiently great. However, considering that the chemical storage tank116is located at some distance from the gantry14in the presently described example of the invention, the inventor has found that the use of the injector244is preferable in this particular application.

An optional feature depicted in the view ofFIG. 3is a second chemical storage tank116afor containing a second chemical114a. In this example a second chemical flow pump206a, a second proportioning solenoid valve208a, a second level sensor126and a second210chemical flow sensor210aare provided so that the control unit120can optionally provide a different chemical114ato the gantry14. Indeed any quantity of different chemicals (not shown) might be provided using repetitive iterations of these components. In one proposed embodiment of the invention, three chemicals (not shown) will be provided to the gantry14in this manner. Optionally, a mixture of chemicals116and116acould be provided.

In the embodiment of the invention shown and described in relation toFIG. 3, a plurality of check valves260are located as shown in the drawing ofFIG. 3to prevent backflow of the chemicals114,114aand/or the water109.

FIG. 4is a flow diagram depicting the inventive vehicle wash chemical proportioning method. According to the present inventive method400, in a measure water flow operation402, flow of the water is measured as previously discussed herein by the water flow sensor112, the water flow sensor204, or an equivalent. In a calculate chemical flow operation404, the control unit120uses the measured water flow determined in the previous operation, and a predetermined desired concentration, to calculate the desired quantity of chemical114to be added to the mix, using an algorithm as previously discussed herein. In an adjust chemical flow operation406the control unit120controls a metering apparatus such as the metering pump124and/or one or more proportioning solenoid valves208,208a, or an equivalent, to control the quantity of chemical114,114abeing dispensed, as has been previously discussed herein. In a measure chemical flow operation408the control unit120monitors the flow of the chemical114, as described previously herein, to determine if the previously calculated quantity of chemical114is being dispensed. According to the example ofFIG. 4, the entire operation is repeated as long as the system is in operation, in order to adjust to changes in demand and or other variations as previously discussed herein. It is also within the scope of the invention that only the final two operations406and408be repeated until the system reaches a desired equilibrium state and, thereafter, the entire method be repeated while the system is in operation.

Various modifications may be made to the invention without altering its value or scope. For example, alternative methods and/or means for monitoring flow of the water109and/or the chemical114, or for adjusting the flow of the water109and/or the chemical114might be employed.

All of the above are only some of the examples of available embodiments of the present invention. Those skilled in the art will readily observe that numerous other modifications and alterations may be made without departing from the spirit and scope of the invention. For example, the present invention may be used in systems other than gantry or wand systems, such as conveyor-type vehicle wash systems, drive-through wash systems, or other types of stationary, variable demand spray-wash systems. Accordingly, the disclosure herein is not intended as limiting and the appended claims are to be interpreted as encompassing the entire scope of the invention.

INDUSTRIAL APPLICABILITY

The inventive chemical ratio proportioning apparatus100,200and associated method400are intended to be widely used in the vehicle wash industry. In particular, the invention is particularly applicable to truck washes, wherein a great quantity of chemicals are used and, thus, it is extremely important to keep the ratio of chemical to water solvent at an ideal proportion. It should be noted that the inventive method and apparatus will work with almost any viscosity of chemical product, and that the inventive method and apparatus can be adapted for use with a great variety of gantry and spray wand configurations.

Since the chemical ratio proportioning apparatus100,200and associated method400of the present invention may be readily produced and integrated with a great variety of vehicle wash devices and configurations, and since the advantages as described herein are provided, it is expected that it will be readily accepted in the industry. For these and other reasons, it is expected that the utility and industrial applicability of the invention will be both significant in scope and long-lasting in duration.