The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:
Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.
Referring to
Sensors 34/84 are interfaced to the pumps 10/60, shafts 32/82 or sources of motion 30/80. The sensors generate a number of pulses proportional to the movement of the shafts 32/82, thereby generating a signal indicative of the amount of component pressurized by their respective pump 30/80. There are many such sensors known in the art. Some use magnets and reed-relays or coils to sense the movement of the shafts 32/82. Some use a light source and light detector along with an interrupter coupled to the shafts 32/82, whereby as the shaft turns, the light beam is interrupted by the interrupter one or more times per revolution. Other examples of sensors that work equally as well are pneumatic proximity sensors and electronic proximity sensors. Although such sensors are capable of generating a wide range of pulses per revolution (from 1 pulse per revolution to over 100 pulses per revolution), it is preferred that the range be from 4 to 20 pulses per revolution.
The output signals 35/85 of the sensors 34/84 are interfaced to a controller 40. The controller 40 is a programmable logic controller (PLC) as known in the industry such as a programmable microcontroller or other processor based controller. An exemplary controller is shown in
The electrical output signals 46/48 from the controller 40 adjust the air pressure output of air pressure modulators 56/54. The air pressure modulators 56/54 have inputs 52 from a standard source of air pressure 50 which is, for example, an air pressure distribution system within a factory or an air compressor and air storage tank. The outputs of the air pressure modulators 56/54 are proportional to the electrical signals 46/48 coming from the controller 40.
The air pressure output from the air pressure modulators 56/54 is coupled to fluid regulators 22/72 through air pressure conduit 58/59. The fluid regulators 22/72 adjust the flow of the components 16/66 being pumped out of reservoirs 14/64 through siphon tubes 12/62. The components 16/66 are pumped by pumps 10/60 through pressure tubes 20/70 to the fluid regulators 22/72. The fluid regulators 22/72 adjust the amount of components 16/66 that pass through to the output tubes 24/74 and eventually mix in a manifold 90 and are outputted to pressure tube 92 to a nozzle, sprayer or other output device (not shown).
Referring now to
Sensors 34/84 are interfaced to the pumps 10/60, shafts 32/82 or sources of motion 30/80. The sensors generate a signal proportional to the movement of the pumps 10/60, thereby generating a signal indicative of the amount of component pressurized by their respective pump 30/80. There are many such sensors known in the art. Some use magnets and reed-relays or coils to sense the movement of the shafts 32/82. Some use a light source and light detector along with an interrupter coupled to the shafts 32/82, whereby as the shaft turns, the light beam is interrupted by the interrupter one or more times per revolution. Other examples of sensors that work equally as well are pneumatic proximity sensors and electronic proximity sensors. Although such sensors are capable of generating a wide range of pulses per revolution (from 1 pulse per revolution to over 100 pulses per revolution), it is preferred that the range be from 4 to 20 pulses per revolution.
The output signals 35/85 of the sensors 34/84 are interfaced to a controller 40. The controller 40 is a programmable controller as known in the industry such as a programmable microcontroller or other processor based, an example of which is shown in
In this embodiment, the electrical output signals 46/48 from the controller 40 are coupled directly to fluid regulators 122/172. The fluid regulators 122/172 adjust the flow of the components 16/66 being pumped out of reservoirs 14/64 through siphon tubes 12/62. The components 16/66 are pumped by pumps 10/60 through pressure tubes 20/70 to the fluid regulators 22/72. The fluid regulators 122/172 adjust the amount of components 16/66 that pass through to the output tubes 24/74 and eventually mix in a manifold 90 and are outputted on pressure tube 92 to a nozzle, sprayer or other output device (not shown).
Referring now to
Next, the second DAC (DAC-B) 245 is controlled to output a voltage proportional to the desired ratio to the second regulator 72. In this example, it is controlled to output a voltage of approximately B divided by A times the maximum voltage 104. This equation assumes that the regulator operates in a linear fashion, e.g., if 10VDC is “full-on,” 5VDC is ½ open and 2.5VDC is ¼ open. This output voltage partially opens the second regulator 72, thereby outputting a lesser amount of the second component 66 than the first component 16. Next, two counters, Counter-A and Counter-B are set to zero 106 and pulses from each of the first sensor 34 and second sensor 84 are counted for a period of time in Counter-A and Counter-B respectively 108. These pulses are, for example, counted by counting the number of interrupts caused by inputs 35/85 or by a program loop that constantly checks for transitions of inputs 35/85 or by any other way known in the industry. This step 108 is performed for a fixed amount of time, after which the current output ratio is determined by dividing Counter-B by Counter-A 112. If the current output ratio is equal to the desired ratio 114, the above three steps are repeated. If not, if the current output ratio is less than the desired ratio 116, the second DAC (DAC-B) output voltage is decreased 118, thereby decreasing the rate of flow though the second regulator 72 and decreasing the proportion of the second component 66 in the output 92 and the process continues by resetting the counters 106. Otherwise, the current output ratio is greater than the desired ratio and the second DAC (DAC-B) output voltage is increased 120, thereby increasing the rate of flow though the second regulator 72 and increasing the proportion of the second component 66 in the output 92 and the process continues by resetting the counters 106. As stated before, if B is greater than A, the same process works by reversing the roles of DAC-A 240 and DAC-B 245, whereby DAC-B 245 is set to full output voltage and DAC-A 240 is controlled proportionally.
Referring now to
Also connected to the processor 210 is a system bus 230 for connecting to peripheral subsystems such as digital analog converters (DAC-A 240 and DAC-B 245 in this example), input receivers 250, an optional graphics adapter or display controller 260 for displaying user prompts and status and an input device such as a keyboard, keypad, thumbwheel switches or potentiometer 270. Any known method for inputting the desired ratio can be used as an input device 270 to the controller 40. The graphics adapter 260 receives commands and display information from the system bus 230 and generates a display image that is displayed on the display 265. The display can be a graphics display or text display such as a dot-matrix display or an array of numeric or alphanumeric displays as known in the industry.
The digital to analog converters 240/245 provide an output voltage 46/48 that is controlled by the processor 210. In the present invention, the output voltage is directed to control the rate of flow from the pumps 10/60.
The input system 250 accepts input signals from the sensors 34/84 on its inputs 35/65 and lets the executing program determine the number of rotations of the pumps 10/16 either by polling the input or by interrupting the running program, as known in the industry.
Referring now to
Sensors 34/84 are interfaced to the pumps 10/60, shafts 32/82 or sources of motion 30/80, although in some embodiments sensor 84 is omitted. The sensors generate a number of pulses proportional to the movement of the shafts 32/82, thereby generating a signal indicative of the amount of component pressurized by their respective pump 30/80. There are many such sensors known in the art. Some use magnets and reed-relays or coils to sense the movement of the shafts 32/82. Some use a light source and light detector along with an interrupter coupled to the shafts 32/82, whereby as the shaft turns, the light beam is interrupted by the interrupter one or more times per revolution. Other examples of sensors that work equally as well are pneumatic proximity sensors and electronic proximity sensors. Although such sensors are capable of generating a wide range of pulses per revolution (from 1 pulse per revolution to over 100 pulses per revolution), it is preferred that the range be from 4 to 20 pulses per revolution.
The output signals 35/85 of the sensors 34/84 are interfaced to a controller 40. The controller 40 is a programmable logic controller (PLC) as known in the industry such as a programmable microcontroller or other processor based controller. An exemplary controller is shown in
The electrical output signal 48 from the controller 40 adjusts the air pressure output of an air pressure modulator 56. The air pressure modulators 56 has an input 52 from a standard source of air pressure 50 which is, for example, an air pressure distribution system within a factory or an air compressor and air storage tank. The output 58 of the air pressure modulator 56 is proportional to the electrical signal 48 coming from the controller 40.
The air pressure output from the air pressure modulators 56 is coupled to a fluid regulator 22 through air pressure conduit 58. The fluid regulators 22 adjust the flow of the component 16 being pumped out of the reservoir 14 through a siphon tube 12. The components 16/66 are pumped by pumps 10/60 through pressure tubes 20/70. The second component 66 is pumped unregulated while the first component 16 is regulated by the fluid regulator 22. The fluid regulator 22 adjusts the amount of the first components 16 that pass through to the output tube 24 and eventually mix in a manifold 90 and outputted to pressure tube 92 to a nozzle, sprayer or other output device (not shown). In this embodiment, the ratio of components 16/66 must be such that the first component 16 is proportionately less than the second component 66, being that the second component 66 always flows at a rate of 100%. Therefore, the sample algorithms described in
The above description is for the fluid proportioning of two components 16/66. The described system is scalable to any number of fluid components by providing additional pump systems, sensors and regulators. In most cases, the same controller provided with additional inputs and analog outputs can monitor several sensors while controlling several regulators. There are many methods of providing analog outputs from a controller and all are versions of converting digital to analog; or digital-to-analog converters. There are many sensors known that provide outputs relational to the number of turns or cycles of a pumping system and, likewise, many ways for a controller to monitor these sensors. The sensors and monitor described are an example of such.
Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
It is believed that the system and method of the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.