[0001]    CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
         [0002]    This application claims the benefit of U.S. provisional application No. 61/839,520 filed on Jun. 26, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    This invention concerns monitoring the level of chemical solutions stored in containers such as drums, and in particular various cleaning agents used in automatic car wash systems. 
         [0004]    In automatic car washes, cars are advanced through a carwash “tunnel” by a conveyor and various cleaning and related operations are performed at locations along the tunnel by equipment mounted to arches and other supports. A tunnel control activates the various pieces of washing equipment as the car is moved along the tunnel. 
         [0005]    A number of chemicals in water solutions are applied during the washing process, such as presoaks, wheel rim cleaners, soaps, foaming detergents, waxes in several colors, drying sealer waxes, rain coats, etc. 
         [0006]    Typically, not every car will have every chemical solution applied as some cleaning or treating steps are only optionally offered to the customer. 
         [0007]    As noted, the various chemical solutions are stored in containers, typically drums or tanks, and an associated mixing/dispensing apparatus draws out a predetermined chemical solution, mixes it with water in a mixing tank to further dilute the same. The diluted solution is then pumped to nozzles or other applicators along the car wash tunnel to be applied if the tunnel control calls for application of that solution on a particular car being conveyed through the tunnel. 
         [0008]    Keeping the drums supplied with the chemical solutions is a constant need, and in the past, it has been proposed to monitor the chemical level with sensors connected to a display with wiring, so that staff personnel can view the fill state of each drum conveniently at a central location. 
         [0009]    However, the extensive wiring required presents a challenge to keep the installation costs low enough to be practical for a car wash business which typically operates on a tight budget. 
         [0010]    In addition, various malfunctions are sometimes presented, requiring proper attention of car wash or supplier personnel, to maintain an effective monitoring system after its installation. 
         [0011]    This includes malfunctioning sensors due to the presence of contamination, mispositioning of the liquid level sensors, failure of various components, leaks in the plumbing, wiring defects, etc. 
         [0012]    As noted, the chemical solutions in the drums need to be replenished periodically and any automated system must preferably not require extensive plumbing and wiring, nor extensive disassembly or reassembly steps. 
         [0013]    Sensors for monitoring the fill state of each drum should therefore easily be installed and should reliably monitor the state of each drum. 
         [0014]    It is an object of the present invention is to provide a sensor and system for reliably monitoring the fill state of a number of drums for an automatic car wash which can be installed without requiring extensive wiring or assembly steps to install or extensive maintenance to keep in good operating order. 
         [0015]    It is a further object of the present invention to provide a self-contained quickly installable level sensor probe for use in maintaining automatic car wash chemical solution levels in storage containers such as drums. 
       SUMMARY OF THE INVENTION 
       [0016]    The above recited objects and other objects which will be understood by one skilled in the art are achieved by a system which includes liquid level sensor probes each comprised of a elongated clear tube of a length able to reach a point adjacent the bottom of the storage containers such as drums when inserted through a hole in the top of the drum, the tube supporting a sealed enclosure at the top end which is thereby located a short distance above the top of an associated drum. 
         [0017]    The enclosure houses various electronic components including a sonar sensor at the top of the tube able to direct ultrasonic waves down the tube towards the liquid contained in the tube, the chemical solution in the tube assuming the same level as in the remainder of the drum. Return waves receive reflected from the liquid in the tube are detected at a time determined by the sensor, and the level being calculated by processor from this data. 
         [0018]    According to the present invention, any of several common defects in the level sensors are detected by an analysis carried out by the electronic processor housed within the enclosure. These defects include a disconnected level sensor, a defective level sensor, a sensor out of the drum and a contaminated sensor tube alarm displays alert support personnel of the problem. 
         [0019]    The enclosure also houses a microprocessor which is programmed to carry out the electronic processing references above, which also carries out the liquid level measuring analysis, and other functions including operation of a wireless transmitter/receiver, associated circuits, for conditioning of a battery power source to operate the electrical components and devices, a vehicle counter circuit, tank identification, date and time stamps and a temperature sensor. 
         [0020]    A read and refill switch operated by the use of an external hand held magnet allows a reset of the level sensing process after the drum is refilled and a display of the drum level data whenever activated by the magnet. LED warning/function indicators are able to be seen through a clear cover on the front side of the enclosure. 
         [0021]    A wireless transmitter/receiver antenna is mounted on the exterior of enclosure, and an electrical lead for a car counter passes through the enclosure and is associated with a magnetic sensor located next to a solenoid valve in a mixer/dispenser into which the chemical solution in the drum is drawn, mixed with water and the dispensed from nozzles or other chemical solution applicators in the car wash tunnel. 
         [0022]    The data generated relative to the level of liquid and the state of the sensor components is wirelessly transmitted to a computer/display/server where it is available to be seen. 
         [0023]    The same data may be transmitted from the computer/display/server via the internet to a website allowing offsite reference of the state of all of the drums associated with an automatic car wash. 
         [0024]    The computer/display can utilize the data to generate reports and analysis of the data, such as usage, costs, at regular intervals and generate alerts therefrom for leaks, low/high drum liquid levels, under/over usages of the anomalies in liquid level changes, and other conditions needing attention. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a diagrammatic depiction of an automatic car wash connected to an array of storage containers and associated liquid level sensors connected to mixer/dispensers, and a computer/display/server wirelessly receiving and displaying the same information generated. 
           [0026]      FIG. 2  is an enlarged pictorial view of a typical container drum with an associated mixer/dispenser, a wirelessly connected computer/display/server and a fragmentary portion of a car wash tunnel arch component. 
           [0027]      FIG. 3  is a pictorial view of a sensor probe tube with the electronics enclosure mounted thereto. 
           [0028]      FIGS. 3A and 3B  are right and left enlarged side views of the electronics enclosure portion mounted to the sensor tube shown in  FIG. 3 . 
           [0029]      FIG. 4  is an enlarged front view of the electronics enclosure with the transparent cover removed to show the various components housed therein. 
           [0030]      FIG. 5  shows the electronics enclosure with the cover installed and the associated car counter sensor and lead. 
           [0031]      FIG. 6  is a block diagrammatic representation of the electronic circuitry contained in the electronic enclosure on the liquid level sensor tube. 
           [0032]      FIG. 7  is a flow chart showing the microprocessor programming used to carry out the signal processing with associated electronic circuitry to detect common probe sensor defects. 
           [0033]      FIG. 7A  is a flow chart depicting data analysis for detection of conditions which are anomalies. 
           [0034]      FIG. 8  is a plot of signals generated by the level sensor when contamination of the sensor probe tube is present to enable detect of such contamination. 
           [0035]      FIG. 9  is a plot of signals when a level determination is carried out without the presence of a solid contaminant or excessive foam in a sensor probe tube. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of  35  USC  112 , but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
         [0037]    Referring to  FIG. 1 , a series of four chemical solution storage containers such as tanks or drums  10 A- 10 D are shown which each supply a particular chemical solution to a respective mixer/dispenser  12 A- 12 D associated with a particular applicator in the car wash tunnel. 
         [0038]    The mixer/dispensers  12 A- 12 D each supply chemical solutions to applicator equipment located along a car wash tunnel  14  when activated under the control of a tunnel control  16 . 
         [0039]    The chemical solution from each drum  10 A- 10 D is drawn into the mixing associated mixer/dispenser  12 A- 12 D via piping  18  and mixed therein with additional water from a water supply  20 . Discharge of a diluted volume of chemical solution on to a car is carried out by a particular applicator equipment such as spray jets (not shown) in the car wash tunnel  14 . 
         [0040]    This is a conventional arrangement in very widespread use in the automatic car wash industry. 
         [0041]    According to the present invention, a self-contained liquid level sensor probe  22 A- 22 D is simply inserted into a matched hole formed in the top of a respective drum  10 A- 10 D without any mountings or wiring or plumbing connections necessary, except to the very limited extent described below. 
         [0042]    As will be described further herein, each of the self-contained liquid level sensor probes  22 A- 22 D has an enclosure  26  mounted to the top of a clear plastic tube  28 , the enclosures each containing the associated electronics and sensors for carrying out the liquid level determinations of the associated drum  10 A- 10 D, a wireless transmitter/receiver  42  for sending data to a computer/display/server  24 , and a battery power source  44  for powering these components to substantially eliminate wiring or other extensive hook ups when the sensor probes  22 A- 22 D are installed. 
         [0043]    The only openings in the watertight enclosure  26  include one at the bottom to receive the sensor tube  28 , which is long enough to reach a point adjacent the bottom of the associated container drum  10 , and to support the enclosure  26  at a point space a short distance above the top of the container drum  10 . 
         [0044]    An antenna  30  for the wireless transmitter is also connected through an opening in a back wall of the enclosure  26 . 
         [0045]    Additionally, an electrical lead  32  passes out of the enclosure  26  to a sensor  34  which is mounted next to a solenoid  36  included in the associated mixer/dispenser  12 A- 12 D ( FIG. 2 ), which is activated by the tunnel control to start a pump  41  when application of the chemical solution is called for to cause a flow of diluted chemical solution from a mixing tank  38  into a connected applicator in the car wash tunnel  14 . 
         [0046]    A volume of the chemical solution in each drum  10 A- 10 D is drawn into the associated mixing tank  38  via a line  18  as by an inductor  40  and water from a pressurized water supply  37  is also mixed to further dilute the chemical solution. 
         [0047]      FIG. 3  shows the interior of the enclosure  26  with a transparent cover  48  removed, showing a wireless transmitter/receiver  42 , a circuit board  45 , battery power packs  44  and ultra sonar sensor  46  are mounted therein. 
         [0048]    The ultrasonic sensor  46  is affixed to the top of the sensor probe tube  28  which in turn is affixed to enclosure  26  by watertight fittings  27 ,  29  so as to be able to direct pulses of sonic waves down the tube  28  to the level of the liquid therein from which they are reflected. 
         [0049]    The enclosure  26  normally has the front cover  48  installed, but since the cover  48  is transparent, LED indicator lights  50  in the enclosure  26  may be observed without the necessity of having any opening in the enclosure  26  or cover  48  to externally mount the LED&#39;s. 
         [0050]    Thus, the possibility of water leakage into the enclosure  26  is minimized, an important advantage in the wet environment of an automatic car wash. 
         [0051]    The clear sensor probe tube  28  allows easy drop in installation into various sizes and shapes of drums  10 , and easy detection of any debris that might collect in the sensor tube  28  and interfere with the level measurement process. The sensor tube completely encloses the liquid therein to prevent the drying of any chemical on the inside of the sensor probe tube  28  and thus minimizes the need for cleaning of the tubes  28 . 
         [0052]    Then closed chamber provided by the sensor probe tube  28  also minimizes false liquid level determinations from the effects of wind, condensation, debris, etc. 
         [0053]    The circuit board  42  includes magnetically operated switches  52 ,  54  (depicted in  FIG. 6 ) adjacent opposite sides of the enclosure  26 , switch  52  when activated causing a reset to start when a drum  10  is refilled, and switch  54  when activated causing a reading of the data concerning the state of the associated tank to be displayed whenever desired without waiting for the next periodic reading/display of the level of chemical solution in the associated drum  10 . Switch activation is accomplished by simply placing a magnet  60  against respective areas  56 A,  56 B of the enclosure exterior where the respective switches  52 ,  54  are positioned within the enclosure ( FIGS. 3A ,  3 B). 
         [0054]    Referring to  FIG. 6 , the components housed within the enclosure  26  are depicted in block diagrammatic form along with a diagram of a container  10 , and liquid level sensor  46  in operation. 
         [0055]    A microcontroller  58  is suitably programmed to operate the various components as described below. 
         [0056]    The liquid level sensor  46  is of a well known ultrasonic sonar type, which generates and sends out a train of sonic waves down the interior of the sensor tube  28 . The waves reflect back from the liquid in the sensor tube  28 , which is suitably positioned so as to have therein the chemical solution at the same level as the level of the chemical solution in the drum  10  as shown. 
         [0057]    From the time elapsed data for the reflected waves to reach the sensor  46 , the distance to the liquid is computed in the well known manner, that distance indicating the level of liquid in the sensor tube  28  and the drum  10  itself. 
         [0058]    In order to make the operation of the sensor  46  more reliable and accurate several potential problems occurring on occasion and causing errors are detected and signals generated such as to set off alarms to alert service personnel of their existence. 
         [0059]    These problems include a disconnected level sensor, a defective level sensor, a sensor positioned out of its drum, and a contaminated sensor tube or the presence of a significant level of foam in the sensor tube. 
         [0060]    The flow chart of  FIG. 7  depicts how the existence of each of these conditions are detected upon initiating a level reading. 
         [0061]    Firstly, if a target is found even before the sonic waves are generated, the sensor is wired such that an indication of the presence of a target before sensing begins, then the sensor  46  is not connected. 
         [0062]    That is, if at initial start up of a periodic measurement cycle, a target is immediately indicated by the sensor  46 , as indicated in block  62 , i.e., before any sonic waves are generated, this means that the sensor  46  is not connected properly and a corresponding error message is generated, (block  64 ). 
         [0063]    After that initial check, a timer is started block ( 66 ) which generates sonic pluses directed down the length of the sensor probe tube  28  (block  68 ). 
         [0064]    After a short delay (block  70 ), the existence of sensor “ring” is searched. That is, continued pulsing normally occur for a brief period when a pulse train is generated. 
         [0065]    If this “ring” is not detected (block  72 ), the sensor  46  is defective and a corresponding error message is generated at (block  74 ). 
         [0066]    If the ring is detected, the next step, after a short dead zone delay present in every sensor set up expires (block  76 ) to determine if a return signal or target is found before the timer expires ( 78 ). If the set interval timer expired, and no return signal has been detected, this means the sensor  46  is out of the drum  10 , and a corresponding error message is generated (block  80 ). 
         [0067]    If a target is found before the timer expires (block  82 ), the process continues and the timer value at the time when the target is found is saved (block  84 ). 
         [0068]    If the timer is expired (block  86 ), the distance of the liquid level is calculated (block  88 ). 
         [0069]    If the timer is not expired, and an additional target is found (block  90 ), the number of additional targets found is counted ( 92 ), repeating until the timer is expired. 
         [0070]    If the additional target count is greater than 0 (block  94 ), this means that one or more return signals has been generated by excessive foam or the presence of a solid contaminant, and a corresponding error message is generated. 
         [0071]    This is seen in  FIGS. 8 and 9  where an additional return is detected, caused by the presence of a solid contaminate or substantial layer of foam in the sensor probe tube  28 , ( FIG. 8 ) only one return signal is created when the tube is clear ( 98 ) ( FIG. 9 ). 
         [0072]    Additional system anomalies can occur, i.e., drum filing with water diverting from water supply, drum draining siphoning, chemical useage not corrected, useage rate not correct, low battery, temperature outside limits—ambient, disconnected level sensor, sensor out of drum, contaminated sensor tube foam in sensor tube. 
         [0073]    Analysis of the data generated can detect these conditions, as indicated in  FIG. 7A . 
         [0074]    The data is collected (block  100 ) and stored (block  102 ). 
         [0075]    If in successive cycles, the level of liquid has declined to a greater degree than what corresponds to the volume of solution which should have been applied, as determined by data analysis; this detects an unprogrammed draining of a drum ( 103 ) can be caused by an unwanted siphoning water out of the drum or from some leak; a corresponding error signal is generated (block  104 ). 
         [0076]    If not, if the drum is filing (block  106 ) water from the water supply entering the drum due to some condition in the plumbing. 
         [0077]    If so, corresponding alarm display is generated (block  108 ). 
         [0078]    If the drum  10  is draining, but in correspondence with expected amount, but the vehicle counter count does not increase (block  110 ) then the counter is defective and a corresponding alarm display is generated (block  112 ). 
         [0079]    Then if the chemical solution useage calculated is out of the normal range (block  114 ) then a corresponding alarm display is generated (block  116 ). 
         [0080]    If the sensed temperature is out of the preset operating range (block  118 ), a corresponding alarm/display is generated (block  120 ). 
         [0081]    Finally, if the sensed battery power voltage declines to an unacceptable degree ( 122 ), then a corresponding alarm/display is generated (block  124 ). 
         [0082]    These analyses can be carried out by the microprocessor  58 . 
         [0083]    Referring again to  FIG. 6 , other circuits can be included on the circuit board  42 . 
         [0084]    The battery power source  44  may have a power switch  126  and power jack  128  for connection to an external power source (not shown). 
         [0085]    A battery conditioning circuit  130  saves power by turning off all power when the liquid level is not being measured which takes place only at intervals (typically every hour). The battery power is divided into high power for use with the sensor  46  by a high power enable circuit  136 , and low power for use in the rest of the circuitry by a logic power circuit  132 . 
         [0086]    The signals to the sensor  46  are generated and conditioned by a signal generating circuit  134 A and signal conditioning circuit  134 B. 
         [0087]    A vehicle counter circuit  138 , temperature sensor circuit  140 , and an address select circuit  142 , are operated by software program of the microprocessor  58 . 
         [0088]    An LED status circuit  144  is connected to the microprocessor  58  and wireless transmitter/receiver  42 . 
         [0089]    The computer/display/web server  24  has an antenna sending/receiving to the wireless transmitter/receiver  25 . The computer/display/server  24  allows review of the readings and alarms, etc. remotely by accessing a website where all of the displays and alarms are uploaded via the internet to enable remote access.
A sensor probe for monitoring levels of chemical solutions used in automatic car washes, the sensor probes comprising an elongated sensor probe tube able to be installed by being inserted into a hole in the top of storage drums. A sealed enclosure mounted to the top of the tube is thereby positioned above the associated tank, which enclosure contains a liquid level sensor and a wireless receiver/transmitter able to send data to a computer/display/and web server.