Patent Description:
Eductors are devices that pass a liquid through a choke to generate the Venturi effect. The suction generated by the Venturi effect is used to draw another liquid into the eductor. For example, water running through the eductor may cause a chemical product to be drawn into the eductor, where it mixes with the water and is subsequently discharged as a dilute solution. Eductors are often used to mix chemical products with water in dispensing systems to produce small batches of chemical solutions. These batches of chemical solutions may be discharged into a container for later use, a washing machine, or some other apparatus or process that requires dilute chemical solutions.

<CIT> discloses a chemical injection system for use in a vehicle wash system having a single spray arch that distributes a plurality of various chemicals onto a vehicle during the wash process. The chemical injection system includes a high pressure supply manifold formed from stainless steel that receives a high pressure supply of inlet water. The supply manifold receives a plurality of individual chemical injectors that are each connected to a supply of one or more chemicals. Each of the chemical injectors includes a one-way valve that allows the chemical agent to flow in only one direction and be introduced into the respective inlet line through the Venturi effect created by the flow of water through the chemical injector.

One problem with dispensing systems that use eductors is that the pressure of the diluent used to feed the eductors must be above a minimum level to produce adequate suction on the chemical inlet side of the eductor. If the pressure falls below the minimum level, the amount of chemical product drawn into the eductor may be insufficient for the resulting solution to perform properly. Moreover, the concentration of the chemical product in the chemical solution discharged from the eductor can vary with the pressure of the diluent across a wide range of operating pressures. This can lead to solutions being specified at higher concentrations than needed to ensure that acceptable levels of chemicals are in the solution when the diluent pressure is at the low end of the operating range of pressures. Another problem with dispensing systems that use eductors is that the internal channels of the eductor can become clogged, which can also affect the concentration of chemicals in the chemical solution discharged by the eductor.

Therefore, there is a need for improved systems, methods, and computer program products for dispensing chemical solutions using eductors that provide solutions with more consistent concentrations.

According to the present invention, there is provided a portion of a dispensing system comprises a flush manifold including a plurality of intake ports, the plurality of eductors, and a check valve. Each eductor includes the inlet port that is selectively fluidically coupled to the source of the diluent, a pickup port fluidically coupled to a source of the chemical product, and the discharge port configured to discharge the chemical solution in response to the diluent being coupled to the inlet port. The check valve couples the discharge port of one of the eductors to one of the intake ports of the flush manifold.

In another embodiment of the dispensing system, the check valve comprises an upstream chamber, a downstream chamber fluidically coupled to the upstream chamber by an opening, and a closing member configured to fluidically isolate the downstream chamber from the upstream chamber by covering the opening in the absence of a flow of fluid from the upstream chamber to the downstream chamber.

In one embodiment of the dispensing system, the check valve further comprises an elastic member that urges the closing member into contact with the opening in the absence of the flow of fluid from the upstream chamber to the downstream chamber.

In another embodiment of the dispensing system, the opening is defined by a valve seat.

In another embodiment of the dispensing system, where the elastic member enables the check valve to operate as a dynamic flood ring that has a first resistance to the flow of fluid through the eductor in a first state, and a second resistance to the flow of fluid higher than the first resistance in a second state.

In another embodiment of the dispensing system, the first state is an open state and the second state is a closed state.

In another embodiment of the dispensing system, the check valve, operating as a dynamic flood ring maintains the eductor in a flooded state when the check valve, operating as a dynamic flood ring is in the second state.

In another aspect of the invention, another method of performing the dispensing operation is presented. The method includes providing a flow of liquid to the inlet port of the eductor sufficient to flood the eductor, in response to the flow of liquid being provided to the inlet port, providing the first resistance to the flow of liquid out of the discharge port of the eductor, and in response to the flow of liquid to the inlet port being reduced, providing the second resistance to the flow of liquid out of the discharge port.

In one embodiment of the method, the first resistance is lower than the second resistance.

In another embodiment of the method, the first resistance optimizes suction at the pickup port of the eductor, and the second resistance maintains the eductor in the flooded state.

In another aspect of the method, providing the first resistance comprises moving the closing member out of contact with the opening in response to the flow of liquid, the movement compressing the elastic member, and providing the second resistance comprises moving the closing member into contact with the opening in response to urging by the elastic member.

<FIG> depicts an exemplary operating environment for a dispensing system <NUM> in accordance with an embodiment of the invention. The dispensing system <NUM> includes a controller <NUM> and a dispenser <NUM>, and is configured to dispense chemical solutions to a point of use, such as a washing machine <NUM>, through a dispense line <NUM>. The operating environment of the dispensing system <NUM> may include one or more sources of a chemical product <NUM>, <NUM> that are fluidically coupled to the dispenser <NUM>. Exemplary chemical products <NUM>, <NUM> may include chemicals such as detergents, water softening agents, bleaches, and the like. Each source of chemical product <NUM>, <NUM> may include a level sensor <NUM>, <NUM> that provides a signal indicative of a level of chemical product <NUM>, <NUM> remaining in the source to the controller <NUM>.

The controller <NUM> may include a Human Machine Interface (HMI) <NUM>, a processor <NUM>, an input/output (I/O) interface <NUM>, and a memory <NUM>. The HMI <NUM> may include output devices, such as an alphanumeric display, a touch screen, and/or other visual and/or audible indicators that provide information from the processor <NUM> to a user of the dispensing system <NUM>. The HMI <NUM> may also include input devices and controls, such as an alphanumeric keyboard, a pointing device, keypads, pushbuttons, control knobs, etc., capable of accepting commands or input from the user and transmitting the entered input to the processor <NUM>.

The processor <NUM> may include one or more devices configured to manipulate signals (analog or digital) based on operational instructions that are stored in memory <NUM>. Memory <NUM> may be a single memory device or a plurality of memory devices including but not limited to read-only memory (ROM), random access memory (RAM), volatile memory, non-volatile memory, static random-access memory (SRAM), dynamic random-access memory (DRAM), flash memory, cache memory, or any other device capable of storing information. Memory <NUM> may also include a mass storage device (not shown), such as a hard drive, optical drive, tape drive, non-volatile solid-state device or any other device capable of storing digital information.

Processor <NUM> may operate under the control of an operating system <NUM> that resides in memory <NUM>. The operating system <NUM> may manage controller resources so that computer program code embodied as one or more computer software applications <NUM> (such as a dispensing operation application) residing in memory <NUM> may have instructions executed by the processor <NUM>. In an alternative embodiment, the processor <NUM> may execute the applications <NUM> directly, in which case the operating system <NUM> may be omitted. One or more data structures <NUM> may also reside in memory <NUM>, and may be used by the processor <NUM>, operating system <NUM>, and/or application <NUM> to store data.

The I/O interface <NUM> operatively couples the processor <NUM> to other components in the operating environment, such as the dispenser <NUM>, washing machine <NUM>, and level sensors <NUM>, <NUM>. The I/O interface <NUM> may include signal processing circuits that condition incoming and outgoing signals so that the signals are compatible with both the processor <NUM> and the components to which the processor <NUM> is coupled. To this end, the I/O interface <NUM> may include analog to digital (A/D) and/or digital to analog (D/A) converters, voltage level and/or frequency shifting circuits, optical isolation and/or driver circuits, and/or any other analog or digital circuitry suitable for coupling the processor <NUM> to the other components in the operating environment.

The I/O interface <NUM> may be coupled to the washing machine <NUM> by a machine interface <NUM>. The machine interface <NUM> may be configured to transform high voltage trigger signals generated by the washing machine <NUM> into lower voltage signals suitable for the I/O interface <NUM> of controller <NUM> and transmit these low voltage trigger signals to the controller <NUM>. The signals may be transmitted over one or more dedicated signal lines, e.g., using a multi-conductor cable, or over a signal serial data line. For embodiments using a serial data line to communicate with the controller <NUM>, the machine interface <NUM> may further include a processor, a memory in communication with the processor, and a user interface that enables programing of the machine interface <NUM> to translate trigger signals into a suitable serial communication protocol. Machine interfaces are described in <CIT>, the disclosure of which is incorporated by reference herein in its entirety.

The dispenser <NUM> may include an inlet manifold <NUM>, a flush manifold <NUM>, and one or more selector valves <NUM>. Each selector valve <NUM> may selectively fluidically couple the inlet manifold <NUM> to an inlet port <NUM> of a respective eductor <NUM> in response to a signal received from the controller <NUM>. In addition to the inlet port <NUM>, each eductor <NUM> may further include a discharge port <NUM> fluidically coupled to an intake port <NUM> of the flush manifold <NUM>, and a pickup port <NUM> fluidically coupled to a feed line <NUM> from one of the one or more sources of chemical product <NUM>, <NUM>. In an embodiment of the invention, one or more of the pickup ports <NUM> may be coupled to the feed line <NUM> by a check valve <NUM> to prevent a back-flow from the flush manifold <NUM> into the source of chemical product <NUM>, <NUM>.

The inlet port <NUM> may be coupled to the discharge port <NUM> by one or more passages that are configured to produce suction at the pickup port <NUM> in response to a flow of diluent through the eductor <NUM>. The eductor <NUM> may operate by forcing the diluent through a conical body that creates a pressure differential between the inlet port <NUM> and discharge port <NUM>. This pressure differential may generate a vacuum inside the eductor <NUM> that, in turn, generates suction at the pickup port <NUM>. An exemplary eductor <NUM> that may be suitable for use in embodiments of the invention is described in <CIT>, the disclosure of which is incorporated by reference herein in its entirety.

The inlet manifold <NUM> may include an input port <NUM> that is coupled to a source of diluent <NUM> by an inlet valve <NUM> and/or a pressure regulator <NUM>. The pressure regulator <NUM> may regulate the pressure of the diluent <NUM> provided to the inlet manifold <NUM>. The inlet valve <NUM> may be configured to selectively couple the inlet manifold <NUM> to the source of diluent <NUM> in response to signals from the controller <NUM>. The pressure regulator <NUM> may be configured to maintain the pressure of the diluent <NUM> in the inlet manifold at a constant level so long as the pressure provided by the source of diluent <NUM> remains above a minimum level.

The pressure of the diluent <NUM> in the inlet manifold <NUM> may affect the rate at which diluent <NUM> flows through the eductors <NUM>. By isolating the inlet manifold <NUM> from variations in diluent pressure provided by the source of diluent <NUM>, the pressure regulator <NUM> may reduce variances in the concentration of solutions provided to the point of use. For example, regulating the pressure of the diluent may prevent solutions provided to the point of use from being "leaned out" beyond their desired concentration levels by excessive diluent flow levels through the eductors <NUM>.

The dispenser <NUM> may further include a pressure sensor <NUM> located downstream of the inlet valve <NUM>, such as in the inlet manifold <NUM>. The pressure sensor <NUM> may be configured to sense the pressure of the diluent <NUM> on an inlet manifold side of the inlet valve <NUM> and provide a signal <NUM> indicative of the sensed pressure to the controller <NUM>. One sensor that may be suitable for use as pressure sensor <NUM> is the PX26 series pressure sensor available from Omega Engineering of Stamford, Connecticut, United States. The pressure sensor <NUM> may dynamically sense changes in the pressure of the diluent <NUM> during a dispensing operation that includes one or more dispense and/or flush stages. Monitoring the pressure of the diluent <NUM> during a dispensing operation may enable the controller <NUM> to sense a drop of inlet manifold pressure (e.g., due to a drop in the pressure provided by the source of diluent <NUM>) during the dispensing operation, which may cause a corresponding drop in a flow rate of the diluent <NUM> through the active eductor <NUM>.

The pressure sensor <NUM> may be located proximate to a flush valve <NUM> and/or the selector valve <NUM> that is used to perform flush stages. The pressure sensor <NUM> may be operated by an excitation voltage (e.g., a <NUM> V DC voltage), and may output the signal <NUM> (e.g., millivolt range voltage) indicative of the pressure sensed by the pressure sensor <NUM>, e.g., a voltage that is proportional to the incoming diluent pressure. The signal <NUM> may be coupled to the processor <NUM> via the I/O interface <NUM> to provide the processor <NUM> with information on pressure with respect to time during operation of the dispensing system <NUM>. The output signal may be routed to the processor <NUM> on a local printed circuit board or to a remotely operated controller <NUM>.

The dispenser <NUM> may further include a concentration sensor <NUM> configured to detect the concentration of one or more substances (e.g., chemical product, mineral salt, and/or other substance) in the diluent <NUM> and/or dispensed solutions and provide a signal <NUM> indictive of the concentration to the controller <NUM>. The concentration sensor <NUM> may include an optical probe and/or a conductive probe and may be located in the flush manifold <NUM> (depicted) or another point downstream of the eductors <NUM>. For example, the concentration sensor <NUM> may be built into an output port <NUM> of flush manifold <NUM>. In an alternative embodiment of the invention, the concentration sensor <NUM> and/or an additional concentration sensor (not shown) may be located in the inlet manifold <NUM> and used to determine concentrations of substances in the diluent <NUM> prior to mixing with the chemical products <NUM>, <NUM>. Advantageously, locating the concentration sensor <NUM> in the flush manifold <NUM> may allow the dispensing system <NUM> to monitor multiple dispense channels and provide solutions to multiple points of use using a single concentration sensor <NUM> rather than separate sensors that detect the concentration of the chemical product for each individual chemical and/or point of use.

The signal <NUM> provided to the controller <NUM> by concentration sensor <NUM> may be used to determine a characteristic of the solution in the flush manifold <NUM>, such as the concentration of one or more substances (e.g., calcium carbonate and/or magnesium) that contribute to the hardness in the diluent <NUM> and/or the concentration of one or more of the chemical products <NUM>, <NUM>. The signal <NUM> may be an analog signal (e.g., voltage or current) and/or a digital signal. For embodiments in which the signal is a digital signal, the concentration sensor <NUM> may include electronic circuitry that quantifies the characteristic, e.g., as a concentration level in parts-per-million. The controller <NUM> may be configured to sample the signal <NUM> and store these samples and/or the concentrations determined therefrom in memory <NUM> as a sequence of readings indicative of the characteristic. The concentration sensor <NUM> may allow the controller <NUM> to adjust the amount of chemical product dispensed to the point of use during the dispensing operation to account for water hardness and/or variations in chemical product flow rates through the eductors <NUM>. The dispensing system <NUM> may thereby provide more effective solutions as compared to dispensing systems lacking the concentration sensor feature.

In an embodiment of the invention, the concentration sensor <NUM> may comprise a conductivity probe having electrodes that detect the conductivity of liquids in the flush manifold <NUM>. The conductivity probe may provide a signal to the controller <NUM> in the form of an impedance, voltage, or current level indicative of the detected conductivity. The controller <NUM> may be configured to determine the conductivity of the incoming diluent, e.g., during a pre-dispense stage or post-dispense stage flush of the flush manifold <NUM>. Conductivity probes and methods of determining the conductivity of a solution are described in <CIT>.

The flush valve <NUM> may selectively fluidically couple the inlet manifold <NUM> to the flush manifold <NUM> in response to signals from the controller <NUM>. This may allow the controller <NUM> to execute flush stages before and/or after activating the selector valves <NUM> to dispense chemical solutions. These flush stages may be used to clear the flush manifold <NUM> of chemical solutions between dispense stages, transport previously dispensed chemical solutions to the point of use, and/or provide a desired amount of diluent <NUM> to the point of use. In an alternative embodiment of the invention, this flushing feature may be enabled by capping the pickup port <NUM> of one of the eductors <NUM> (e.g., the eductor <NUM> furthest from the output port <NUM> of flush manifold <NUM>) and activating the respective selector valve <NUM> to flush the flush manifold <NUM>. In this case, the flush valve <NUM> may be omitted.

The controller <NUM> may respond to a sensed drop in the pressure of the diluent <NUM>, for example, by increasing an amount of time the respective selector valve <NUM> is kept open. This change in the duration of the dispense stage may compensate for a leaning out of the chemical solution by increasing the volume of the chemical solution provided to the point of use. The leaning out may be due to a reduction in the rate the chemical product <NUM>, <NUM> is drawn into pickup port <NUM> caused by a lower flow rate of diluent <NUM> through the eductor <NUM> than would have occurred if the pressure of the diluent <NUM> had not dropped.

The increase in duration of the dispense stage may be determined by the controller <NUM> based on a known function of the flow rate of the pickup port <NUM> versus the flow rate of diluent <NUM> through the eductor <NUM>. The flow rate of diluent <NUM> through the eductor <NUM> may be determined by the controller <NUM> based on a known function of the flow rate through the eductor <NUM> verses diluent pressure at the inlet port <NUM>. In an alternative embodiment of the invention, the period of time may be determined using a predefined algorithm (e.g., a lookup table) that maps the flow rate of chemical product <NUM>, <NUM> into the pickup port <NUM> to the pressure at the inlet port <NUM>. The controller <NUM> may thereby alter the dispensing operation to compensate for pressure changes in the diluent <NUM> so that the correct dose of chemical product <NUM>, <NUM> is delivered to the point of use.

To keep the total volume of the solution delivered to the point of use consistent between dispensing operations, the controller <NUM> may adjust the volume of diluent <NUM> dispensed during a subsequent flush stage to compensate for changes in the volume of the chemical solution dispensed during the dispense stage. For example, the duration of a post-dispense flush stage may be determined based on a difference between the total volume of solution to be dispensed to the point of use during the dispensing operation, and the volume of the chemical solution/diluent dispensed during any prior flush and/or dispense stages.

During a dispense stage of a dispensing operation, the chemical product <NUM>, <NUM> injected into the diluent <NUM> flowing through the eductor <NUM> may change the conductivity, refractive index, fluorescent properties, and/or other characteristics of the diluent <NUM>. Thus, the chemical solution dispensed during the dispense stage may have a different conductivity and/or refractive index than the diluent <NUM> dispensed during a flush stage. After the dispense stage, the controller <NUM> may execute a flush stage to help remove any residual chemical product from the flush manifold <NUM>, and/or to transport the chemical solution to the point of use. This flush stage may be executed at the end of the dispensing operation, and may return the conductivity and/or refractive index sensed by the concentration sensor <NUM> back to a value associated with the diluent <NUM>.

If the controller <NUM> fails to detect changes in the concentration, conductivity, and/or optical characteristics of the solution flowing through the flush manifold <NUM> in accordance with a predetermined pattern for the dispensing operation being performed, the controller <NUM> may determine that a source of chemical product <NUM>, <NUM> is running low or has run out, or that there is some other problem with the dispensing system. The characteristics of the solution flowing through the flush manifold <NUM> may be in accordance with the predetermined pattern if the characteristics are within a predetermined threshold of an expected value at one or more points in time during the dispensing operation.

In response to a determination the characteristics are not in accordance with the predetermined pattern, the controller <NUM> may alert the user as to which source of chemical product <NUM>, <NUM> and/or dispensing channel appears to have an issue. The controller <NUM> may also disable activation of the selector valve <NUM> associated with that source of chemical product <NUM>, <NUM> until the event is cleared. Advantageously, the concentration sensor <NUM> may be used in this way to determine the status of each source of chemical product <NUM>, <NUM> being used. The ability to detect the concentration of chemical products in the flush manifold using the single concentration sensor <NUM> may allow the dispensing system to avoid placing individual sensors on each feed line <NUM> to detect the presence of absence of chemical product.

In an alternative embodiment of the invention, the controller <NUM> may use a demultiplexer to control the dispenser <NUM> rather than the processor <NUM>. In this embodiment, the demultiplexer may be used to implement logic functions that operate the dispenser <NUM>. In another alternative embodiment of the invention, the dispenser <NUM> may include an interface circuit <NUM> (<FIG>). The interface circuit <NUM> may communicate with the controller <NUM> using a serial data line. The interface circuit <NUM> may be configured to receive data from the controller <NUM> over the serial data line, and to activate/deactivate valves <NUM>, <NUM> based on the received data. The interface circuit <NUM> may be further configured to transmit data to the controller <NUM> using the serial data line. The transmitted data may be indicative of signals generated by various sensors <NUM>, <NUM>. The interface circuit <NUM> may also use flow regulator and/or detection devices to monitor the pressure of the source of diluent <NUM> and transmit these readings to the controller <NUM>. This may enable the controller <NUM> to adjust the period of time the selector valves <NUM> and/or inlet valve <NUM> is activated when the sensed pressure is inadequate to produce full suction in one or more of the eductors <NUM>.

By way of example, the pressure regulator <NUM> may be configured so that the pressure at the pressure sensor <NUM> is normally at a level (e.g., <NUM> PSI) that allows the eductors <NUM> to generate their rated suction when the selector valve <NUM> is open. When an event occurs that drops the pressure of the diluent <NUM>, such as another draw on the source of diluent <NUM>, the controller <NUM> may detect the pressure drop based on a change in the signal generated by the pressure sensor <NUM>. In response to determining that the inlet manifold pressure has dropped below the minimum pressure at which the eductors <NUM> generate rated suction, the controller <NUM> may generate an alarm using the HMI <NUM> or some other indicator, e.g., a buzzer or light. The controller <NUM> may also compensate for the reduced suction at the pickup port <NUM> of the active eductor <NUM> by keeping the selector valve <NUM> open for a longer period of time as described above. For dispensing systems using a common diluent inlet line, a single pressure sensor <NUM> may be used for all dispensing operations. The controller <NUM> may also be configured to verify the dispensing system <NUM> is operating properly based at least in part on the output of the concentration sensor <NUM>.

Dispensing events, such as changes in the pressure of the diluent <NUM>, concentration levels of substances in the diluent <NUM> and/or dispensed solution, and/or low chemical product conditions, may be logged in memory <NUM> for later analysis, and may also trigger visual and/or audible alarms to notify the user of the event.

<FIG> depicts an admittance probe <NUM> that may comprise all or part of the concentration sensor <NUM> in accordance with an embodiment of the invention. The admittance probe <NUM> may include a plurality of electrodes <NUM>, <NUM> coupled to a current source <NUM> and to the inputs <NUM>, <NUM> of a buffer amplifier <NUM>. The electrodes <NUM>, <NUM> may be formed from any suitable conductive material, such as Hastelloy, which is a corrosion resistant nickel-molybdenum-chromium alloy available from Haynes International, Inc. of Kokomo, Indiana, United States. The output impedance of the current source <NUM> and the impedance of the inputs <NUM>, <NUM> of buffer amplifier <NUM> may be high, e.g., on the order of several megaohms. The current provided by the current source <NUM> may be a pulsed current having an amplitude on the order of a microamp. The admittance probe <NUM> may further include an output resistor <NUM> (e.g., a <NUM> kQ resistor) that provides a path for the current of the current source <NUM> and to set the impedance between the electrodes <NUM>, <NUM>. In an embodiment of the invention, the output resistor <NUM> may represent the output impedance of the current source <NUM>. The buffer amplifier <NUM> may be configured to output a low impedance signal <NUM> indicative of a voltage across the electrodes <NUM>, <NUM> and/or output resistor <NUM>.

<FIG> depicts an exemplary embodiment of the admittance probe <NUM> in which the current source <NUM> includes an operational amplifier <NUM> and a transistor <NUM>. The operational amplifier <NUM> may include an inverting input 75a, a non-inverting input 75b, and an output 75c. The transistor <NUM> may include a collector 77a, a base 77b, and an emitter 77c. The inverting input 75a of operational amplifier <NUM> may be coupled to a positive voltage source +V (e.g., Vcc) by a biasing resistor <NUM> (e.g., a <NUM> S2 resistor) and to a negative voltage source -V (e.g., ground) by another biasing resistor <NUM> (e.g., a <NUM> kS2 resistor). The non-inverting input 75b of operational amplifier <NUM> may be coupled to the collector 77a of transistor <NUM>.

The collector 77a of transistor <NUM> and the non-inverting input 75b of operational amplifier <NUM> may be coupled to the positive voltage source +V by another biasing resistor <NUM> (e.g., a <NUM>Ω resistor). The output 75c of operational amplifier <NUM> may be coupled to the base 77b of transistor <NUM>. The emitter 77c of transistor <NUM> may be coupled to the electrode <NUM> and provide the output of the current source <NUM>. A resistor <NUM> (e.g., a <NUM> kΩ resistor) may couple the electrode <NUM> to the negative voltage source -V and provide a path for the current output by current source <NUM> in the event the electrodes <NUM>, <NUM> are in a high impedance environment.

The buffer amplifier <NUM> may include one or more operational amplifiers <NUM>, <NUM>, <NUM> each including a respective non-inverting input 87a, 89a, 91a, inverting input 87b, 89b, 91b, and output 87c, 89c, 91c. The non-inverting inputs 87a, 89a of operational amplifiers <NUM>, <NUM> may be coupled to respective electrodes <NUM>, <NUM> by respective input resistors <NUM>, <NUM> (e.g., <NUM> kΩ resistors). The outputs 87c, 89c of operational amplifiers <NUM>, <NUM> may be coupled to their respective inverting inputs 87b, 89b so that the operational amplifiers <NUM>, <NUM> provide unity gain voltage follower input stages of the buffer amplifier <NUM>.

The output 87c of operational amplifier <NUM> may be coupled to the non-inverting input 91a of operational amplifier <NUM> by a resistor <NUM> (e.g., a <NUM> kS2 resistor) and the output 89c of operational amplifier <NUM> may be coupled to the inverting input 91b of operational amplifier <NUM> by another resistor <NUM> (e.g., a <NUM> kS2 resistor). The non-inverting input 91a of operational amplifier <NUM> may be coupled to the negative voltage supply -V by a resistor <NUM> (e.g., a <NUM> kQ resistor), and the inverting input 91b may be coupled to the output 91c of operational amplifier <NUM> by a feedback resistor (e.g., a <NUM> kS2 resistor) to provide a differential amplifier output stage.

In operation, the controller <NUM> may determine the electrical admittance of the liquid (e.g., chemical solutions and/or diluent <NUM>) in the flush manifold <NUM> on a periodic basis based on the signal <NUM> output by the admittance probe <NUM>. This process may be distinguished from conventional measurements using a conductivity type concentration sensor, which typically includes a voltage source that operates continuously. Advantageously, using a current source <NUM> to determine an admittance value of liquids in the flush manifold <NUM> may avoid the need to characterize mechanical constants of the admittance probe <NUM>, the size or configuration of the electrodes <NUM>, <NUM>, spatial relationships between the tips of the electrodes <NUM>, <NUM>, or temperature correction algorithms that compensate for changes in the signal <NUM> due to variations in the temperature of the liquid.

The admittance probe <NUM> may be configured to detect the admittance of the solution being dispensed proximate to the output port <NUM> of flush manifold <NUM>. Because only a portion of the electrodes <NUM>, <NUM> must be in contact with the solution being measured, the circuitry (e.g., current source <NUM> and buffer amplifier <NUM>) may be located remotely from the electrodes <NUM>, <NUM>, e.g., on the printed circuit board of the controller <NUM>.

The admittance probe <NUM> may have several advantages over sensors using voltage sources. For example, the high output impedance of the current source <NUM> may avoid measurement errors that could otherwise be caused by films or coatings forming on the electrodes <NUM>, <NUM>. That is, any additional series resistance (e.g., several hundred or several thousand ohms) caused by coatings on the electrodes <NUM>, <NUM> may be insignificant compared to the high input impedance of admittance probe <NUM>. The high output impedance of the current source <NUM> may avoid the need to compensate for temperature and resistive losses causes by long wire leads between the current source <NUM> and the electrodes <NUM>, <NUM>. Long leads can also add parasitic capacitance, which in turn may cause conventional monitoring circuits to oscillate. The signal <NUM> output by the admittance probe <NUM> may allow the controller <NUM> to detect changes (e.g., a drop) in the concentration of the ions in a solution based on changes in ionic conduction through the solution as the dispensed chemicals mix with the diluent <NUM>.

The current source <NUM> may be inactive until a measurement is to be made. In response to receiving power or some other suitable signal (e.g., from the controller <NUM>), the current source <NUM> may output one or more pulses of current to the electrodes <NUM>, <NUM>. The admittance probe <NUM> may include a controlled power-on time that provides a pulsed current signal to the electrodes <NUM>, <NUM>, thereby enabling the concentration sensor <NUM> to be activated by the application of power. The pulsed current signal may reduce any effects of polarization that could contribute to fouling of the electrodes <NUM>, <NUM>. Changes in the admittance of the solution in the flush manifold <NUM> may be revealed by the microamp level pulsed signal, any may have a direct correlation to the admittance value of any type of conductive liquid. The signal resulting from the current pulse may be read and converted to a format that can be transmitted to the controller <NUM>, e.g., a voltage and/or frequency component. The output signal <NUM> may be coupled to an analog-to-digital (A/D) converter of the I/O interface <NUM>, to an integrated A/D converter in the processor <NUM>, and/or a capture and compare I/O port. The controller <NUM> may use the admittance information to make changes to the dispensing operation on the fly as the characteristics diluent <NUM> and/or chemical solutions change during a dispensing operation.

During installation of the dispensing system <NUM>, a calibration process may be performed during which diluent <NUM> at a predetermined pressure is provided to the inlet manifold <NUM>. The controller <NUM> may include a calibration mode that allows the user to measure the admittance of the solution in the flush manifold <NUM> while each eductor <NUM> is dispensing chemical. While operating in the calibration mode, the controller <NUM> may sample the output signal <NUM> and store the sampled value in a nonvolatile memory location for each chemical dispensed. This value may then be used as a reference value to help determine if the dispensing system <NUM> is operating properly. For example, during operation of the chemical dispenser, the admittance probe <NUM> may measure the admittance value of the chemical product <NUM>, <NUM> and diluent <NUM> mixture. These admittance values may be compared to the admittance values measured during installation to verify that the active eductor <NUM> is operating properly.

The controller <NUM> may use data obtained from the pressure sensor <NUM> and concentration sensor <NUM> independently or in combination to provide a reliable closed loop dispensing process during all or part of the dispensing operation. If the concentration measurements (e.g., the admittance or optical characteristics of the solution as indicated by output signal <NUM>) do not follow the pattern of concentration verses time defined during the calibration process, the controller <NUM> may determine that the diluent pressure at the inlet manifold <NUM> has changed, e.g., is too low. The controller <NUM> may verify this determination based on readings from the pressure sensor <NUM>. If the output signal of the pressure sensor <NUM> indicates that the diluent pressure level is in a valid operating range when the concentration levels are incorrect, it may be indicative that the chemical product <NUM>, <NUM> is running low (e.g., if the concentration levels are moving over a range of values as slugs of chemical are periodically drawn in to the eductor <NUM>) or has run out (e.g., if the concentration levels are consistently low). In response to detecting a low chemical product condition, the controller <NUM> may alert the user as to which chemical product is having a problem via the HMI <NUM>. The controller <NUM> may also prevent activation of the selector valve for that chemical channel until the low chemical product condition is cleared.

The controller <NUM> may be configured to display current values of the diluent pressure in the inlet manifold <NUM> and/or characteristics of the solution in the flush manifold <NUM> on the HMI <NUM>. The above data, as well as other operational data of the dispensing system <NUM>, may be transmitted to a user device, such as a smart phone or tablet, over a network, e.g., a wireless Wi-Fi or Bluetooth network. The I/O interface <NUM> of controller <NUM> may also include a serial data port that enables the controller <NUM> to communicate locally to a personal computer or other wired network-based device. The dispensing system <NUM> may thereby indicate the occurrence of a dispensing event visually, audibly, or both, on the HMI <NUM> of controller <NUM> or on the user interface of a user device.

<FIG> depicts an exemplary graph <NUM> including a horizontal axis 105a corresponding to a concentration of a chemical product, such as Luster Professional detergent, which is available from Procter & Gamble Inc. of Cincinnati Ohio, a vertical axis 105b corresponding to a refractive index of the solution, data points 109a-109d indicative of the refractive index at specific concentrations of the chemical product, and a plot <NUM> showing a linear approximation of the refractive index of the solution relative to the concentration of the chemical product in the solution. The plot <NUM> may be, for example, a line determined by applying the least-squares analysis to the data points 109a-109d.

As can be seen from the graph <NUM>, the addition of the chemical product to the diluent changes its refractive index. The refractive index of a solution may vary from a base refractive index (e.g., n = <NUM> for pure water) to that of the chemical solution (e.g., n = <NUM> for Luster detergent), with the amount of the change dependent on the concentration of the chemical product in the solution. For example, chemical solutions dispensed to a washing machine may have a refractive index of between <NUM> to <NUM> depending on the chemical product and concentration thereof in the solution. The refractive indexes, or a value of a signal indicative thereof, for individual chemical products may be determined empirically at various concentration levels. These values may be stored as a look up table in memory <NUM> of controller <NUM>, e.g., during a calibration process, and used to determine concentration levels of the dispensed solutions during operation of the dispensing system <NUM>. In cases where the refractive index of the diluted chemical product changes in a generally linear fashion with respect to the level of dilution, it may also be possible to mathematically predict the refractive index. This prediction may be based upon the volume of diluent and the amount of the chemical solution being pumped through the output section taking into consideration a volume of the cross-sectional area.

In an embodiment of the invention, the concentration sensor <NUM> may comprise an optical probe. <FIG> depict exemplary embodiments of an optical probe <NUM> that may be used to detect concentrations of substances based on the refractive index of the solution. For example, in addition to the effects of chemical products discussed above, it has been determined that calcium carbonate and magnesium each uniquely affect the refraction index of the diluent <NUM>, and that this effect on the refraction index of the diluent <NUM> may be detected optically.

Referring now to <FIG> and <FIG>, the optical probe <NUM> may include a holder <NUM>, a light source <NUM>, and one or more (e.g., two) photodetectors <NUM>, <NUM>. The holder <NUM> may be configured to locate the light source <NUM> and photodetectors <NUM>, <NUM> in a fixed position relative to a chamber <NUM> which the solution being measured flows through or otherwise enters. The holder <NUM> may include one or more channels <NUM>-<NUM> that provide one or more optical paths for a beam of light <NUM> emitted by the light source <NUM>. Each of the channels <NUM>-<NUM> coupling the light source <NUM> and photodetectors <NUM>, <NUM> to the chamber <NUM> may include an aperture <NUM>-<NUM> that defines an opening having a predetermined size and shape. For example, the source channel <NUM> may include a circular aperture <NUM> having a diameter of <NUM> or less, and the photodetector channels <NUM>, <NUM> may each include a circular aperture <NUM>, <NUM> having a diameter of <NUM> or less.

The apertures <NUM>-<NUM> may be defined by baffles formed in the channel <NUM>-<NUM> as depicted in <FIG> and <FIG>, or by the diameter of the channel <NUM>-<NUM> itself. The apertures <NUM>-<NUM> may be configured to allow the beam of light <NUM> to reach one or the other of the photodetectors <NUM>, <NUM> when the solution in the chamber <NUM> has a refractive index n specific to that photodetector (e.g., n = <NUM> or <NUM>), and may shield the photodetectors <NUM>, <NUM> from the beam of light <NUM> when the medium in the chamber <NUM> has a different refractive index.

The chamber <NUM> may include one or more walls <NUM> that isolate the other components of the optical probe <NUM> from the medium in the chamber <NUM>, and that have a refractive index the same as or different from the medium in the chamber <NUM>. The optical probe <NUM> may be configured to detect concentrations of minerals in the diluent <NUM> by selecting the dimensions (e.g., T<NUM>, T<NUM>, T<NUM>), refractive indexes, and relative locations of the components of the optical probe <NUM>. The configuration of the optical probe <NUM> may cause the displacement <NUM> of the beam of light <NUM> to align the beam of light <NUM> with a respective photodetector <NUM>, <NUM> when the medium in the chamber <NUM> has a specific concentration of a mineral or a chemical product being measured. Optical probes that work based on changes in refractive index are described in Application No. <CIT>.

<FIG> and <FIG> depict an alternative embodiment of the optical probe <NUM> that includes a light source <NUM>, a sensor <NUM>, an optical element <NUM> (e.g., a prism), a source mask <NUM> including a horizontal slot <NUM>, and a detector mask <NUM> including a vertical slot <NUM>. The light source <NUM> may include a light emitting diode, such as narrow beam infrared light emitting diode, or any other suitable source of light. The optical element <NUM> may be made from a transparent material (e.g., glass or plastic) and include a source facing surface <NUM>, a solution facing surface <NUM> that is optically coupled to a solution <NUM> (e.g., a solution in the interior of flush manifold <NUM>), and a sensor facing surface <NUM> that faces the sensor <NUM>. The source mask <NUM> may be located between the light source <NUM> and the source facing surface <NUM> of optical element <NUM> so that the horizontal slot <NUM> couples light <NUM> from the light source <NUM> into the optical element <NUM>.

The horizontal slot <NUM> may be configured so that the light <NUM> is incident on and distributed relatively evenly across the inward facing side of the solution facing surface <NUM>. As a result, the angle of incidence θi between the light <NUM> and a line normal to the surface <NUM> may increase with the distance from the horizontal slot <NUM> to the surface <NUM>. For given indexes of refraction for the optical element <NUM> and the solution <NUM>, at a specific point indicated by dashed line <NUM>, the angle of incidence θi may reach the critical angle θc. At angles of incidence θi less than the critical angle θc (i.e., to the left of dashed line <NUM>), the majority of the light <NUM> incident on the solution facing surface <NUM> may pass into the solution <NUM>. However, at angles of incidence θi greater than critical angle θc (i.e., to the right of dashed line <NUM>), there may be total internal reflection that causes the majority of the light <NUM> to be reflected downward toward the sensor <NUM> by the solution facing surface <NUM>. The critical angle θc may be determined using the following equation: <MAT> where n<NUM> is the refractive index of the optical element <NUM> and n<NUM> is the refractive index of the solution <NUM>.

Thus, for an optical element <NUM> having a fixed refractive index (e.g., n<NUM> = <NUM>), as the refractive index n<NUM> of the solution <NUM> increases (e.g., from n<NUM> = <NUM> to n<NUM> = <NUM>), the location where the light <NUM> incident on the solution facing surface <NUM> has an angle of incidence θi equal to the critical angle may move from right to left along the solution facing surface <NUM> of optical element <NUM>. This movement is depicted by the position of the dashed line <NUM> shifting from right to left between <FIG> and <FIG>. The increase in the critical angle θc may further result in the reflected light covering a greater portion of the sensor <NUM>, as shown by the increased number of reflected rays in <FIG> as compared to <FIG>. Thus, the refractive index of the solution <NUM> may be inferred by the position and/or size of the illuminated section of the sensor <NUM>.

Advantageously, embodiments of the optical probe <NUM> using the critical angle to detect the refractive index n<NUM> of solution <NUM> can be used to provide feedback to the controller <NUM> on the both the type of chemical product and the duration of the chemical product dispense cycle. The information regarding the refractive index n<NUM> of solution <NUM> may also be used to determine if there is an issue with the chemical product, such as a low or out of product condition.

Embodiments of the optical probe <NUM> that rely on critical angles to determine the refractive index of solution <NUM> are not limited to the exemplary embodiment depicted in <FIG> and <FIG>. For example, the optical element <NUM> could have dimensions and angles other than those of the right-angle prism depicted. Optical elements having shapes other than that of a prism or having multiple components could also be used. For example, an optical window could be used to couple the solution to and/or in place of the optical element <NUM>. Although depicted as being oriented perpendicular/parallel to their respective facing surfaces <NUM>, <NUM>, the light source <NUM> and/or sensor <NUM> could also be oriented at other angles with respect to the surfaces <NUM>, <NUM> of optical element <NUM>.

The sensor <NUM> may include a linear array (e.g., <NUM> × <NUM>) of photodiodes or pixels and associated circuitry that allows charge to build up for a selectable period of time on the photodiodes. The sensor <NUM> may be oriented generally parallel to the sensor facing surface <NUM> of optical element <NUM> to capture the arc of the rays exiting the optical element <NUM>. The refractive index n<NUM> of the solution <NUM> may be determined based on the size of the arc that hits the sensor <NUM>. The sensor <NUM> may output an analog voltage at the end of a sampling cycle indicative of the intensity of light incident on one or more pixels of the array. This signal may be transmitted to the controller <NUM> and used by the controller to determine refractive index n<NUM> of the solution <NUM> being monitored.

<FIG> depicts an alternative embodiment of the optical probe <NUM> that is configured to detect minerals and/or other substances that fluoresce when exposed to short wavelength light, e.g., Ultra-Violet (UV) light. The optical probe <NUM> may include a holder <NUM>, an exciting light source <NUM>, and a photodetector <NUM>. The holder <NUM> may be configured to locate the light source <NUM> and photodetector <NUM> in a fixed position (e.g., a distance and angle) relative to each other and a chamber <NUM> which the solution being measured flows through or otherwise enters. The holder <NUM> may include channels <NUM>, <NUM> that provide an optical path for a beam of light <NUM> emitted by the light source <NUM>, and fluorescent light <NUM> emitted by substances in response to being excited by the beam of light <NUM>.

The chamber <NUM> may include one or more walls <NUM> that isolate the other components of the optical probe <NUM> from the medium in the chamber <NUM>. The optical probe <NUM> may be configured to detect concentrations of substances in the diluent <NUM> based on the amount of fluorescent light <NUM> that is detected by the photodetector <NUM>. The optical probe <NUM> may thereby enable the controller <NUM> to determine the concentration of substances, such as minerals that contribute to water hardness, which may have a direct effect on the cleaning capability of the solution and the amounts of chemicals that should be dispensed into the diluent <NUM>.

However configured, the optical probe <NUM> may be used by the controller <NUM> to determine an equivalent part-per-million level of minerals in the diluent <NUM>. This feedback to the controller <NUM> on the quality of the diluent may allow the controller <NUM> to adjust the amount of chemicals dispensed, e.g., dispensing additional chemicals to compensate for a diluent <NUM> having a high mineral content, and/or dispensing less chemicals if the diluent <NUM> has a low mineral content. This compensation for the mineral content of the diluent <NUM> may be performed, for example, in a laundry application to which the prescribed amount of detergent is based on the size and type of the laundry load and that assumes the dosing amount is correct based on a certain water hardness level.

<FIG> depict front, bottom, back, perspective, and exploded views, respectively of a dispenser <NUM> in accordance with an embodiment of the invention. As best shown by <FIG>, the dispenser <NUM> includes the inlet manifold <NUM>, flush manifold <NUM>, selector valves <NUM>, eductors <NUM>, check valves <NUM>, and interface circuit <NUM>. The dispenser <NUM> further includes a user interface <NUM> (which may be provided by the HMI <NUM> of controller <NUM>) and a housing <NUM> having a front portion <NUM> and a back portion <NUM>.

The front portion <NUM> of housing <NUM> may include openings <NUM>, <NUM> that provide access to the user interface <NUM>, and the back portion <NUM> of housing <NUM> may include openings <NUM> that provide access to input ports <NUM> of check valves <NUM>. Opening <NUM> may provide access to a display <NUM> that displays information about the operation of the dispenser <NUM> to the user, and one or more input devices <NUM> (e.g., buttons) that enable the user to provide data/instructions to the dispenser <NUM>. Opening <NUM> may include a removeable cover <NUM> that provides access to a serial data port <NUM>, such as a Universal Serial Bus (USB) port, which is an industry standard communication protocol managed by the USB Implementers Forum. Dispensing Systems including USB ports are described in <CIT>, the disclosure of which is incorporated by reference herein in its entirety.

The back portion <NUM> of housing <NUM> may include one or more openings <NUM> each configured to receive a keeper <NUM>. A mounting bracket <NUM> may be configured to be mounted to a wall or other support structure, and may include one or more slots <NUM> each configured to receive one of the keepers <NUM>. In operation, the mounting bracket <NUM> may be affixed to the support structure, and the back portion <NUM> of housing <NUM> positioned over the mounting bracket <NUM>. One of the keepers <NUM> may then be inserted through each opening <NUM> to engage a respective slot <NUM> of the mounting bracket <NUM>. The back portion <NUM> of housing <NUM> may thereby be removably mounted to the support structure by securing it to the bracket <NUM>.

The input port <NUM> of inlet manifold <NUM> may include a threaded connector <NUM> configured to receive a threaded end of a diluent supply line. The output port <NUM> of flush manifold <NUM> may include a nozzle <NUM> configured to receive the dispense line <NUM> that conveys the output of the dispensing system <NUM> to the point of use. The nozzle <NUM> may include one or more circumferential barbs <NUM> configured to resist movement of the supply line and provide a secure fluid-tight connection between the nozzle <NUM> and the supply line.

<FIG> is an exploded view depicting an exemplary embodiment of the controller <NUM>. The controller <NUM> may include a housing <NUM> having a front portion <NUM> and a back portion <NUM>, and a Printed Circuit Board (PCB) <NUM>. The PCB <NUM> may include the HMI <NUM>, processor <NUM>, I/O interface <NUM>, and memory <NUM> of controller <NUM>. The front portion <NUM> of housing <NUM> may include an opening <NUM> that provides access to the HMI <NUM>, and an opening <NUM> having a removable cover <NUM> that provides access to a serial data port <NUM>, such as a USB port. A connector <NUM> may be affixed to a back facing side <NUM> of PCB <NUM> by one or more fasteners <NUM>. The back portion <NUM> of housing <NUM> may include an opening <NUM> configured to receive the connector <NUM>. The opening <NUM> may enable the I/O interface <NUM> of PCB <NUM> to be electrically coupled to the dispenser <NUM>, for example, by plugging a connectorized multi-conductor cable into the connector <NUM>.

It has been determined that during operation of a dispensing system that uses eductors, there are operational scenarios in which two different chemicals can mix within an eductor. The chemicals dispensed by an eductor are typically diluted at a diluent to chemical product ratio of between <NUM>:<NUM> and <NUM>: <NUM>. In some cases, different chemicals may react with each other, thereby creating a thick congealed plug. This plug may then block the eductor so that little or no chemical is injected into the flow of diluent. Embodiments of the invention may solve this problem by adding a check valve between the flush manifold and the discharge port of the eductor.

<FIG> depicts a portion of a dispensing system in accordance with an embodiment of the invention that includes a plurality of eductors <NUM>-<NUM> each having an inlet port <NUM>-<NUM> coupled to an inlet manifold <NUM> by a respective selector valve <NUM>-<NUM>, a pickup port <NUM>-<NUM>, and a discharge port <NUM>-<NUM>. Each of the selector valves <NUM>-<NUM> may include a solenoid <NUM>-<NUM> configured to open or close the selector valve <NUM>-<NUM> in response to signals from the controller. In the exemplary embodiment depicted, the discharge port <NUM> of eductor <NUM> is coupled directly to an intake port <NUM> of a flush manifold <NUM>, and the discharge ports <NUM>-<NUM> of the remaining eductors <NUM>-<NUM> are coupled to the intake ports <NUM>-<NUM> of flush manifold <NUM> by check valves <NUM>-<NUM>. The flush manifold <NUM> may comprise one or more modules <NUM>-<NUM> that are configured to be fluidically coupled to each other to form a flush manifold having a desired number of intake ports.

The leftmost or "upstream" eductor <NUM> may be configured as a flush eductor that is used to provide diluent from the inlet manifold <NUM> to the flush manifold <NUM> without injecting any chemical products. The controller may activate the selector valve <NUM> coupling the flush eductor <NUM> to the inlet manifold <NUM> to flush chemical solutions from the flush manifold <NUM>. The flush eductor <NUM> may be a "high flow" eductor as compared to the other eductors <NUM>-<NUM> to shorten flush times, or may comprise a suitably sized conduit that lacks a venturi.

In operation, the controller may sequentially activate one or more of the selector valves <NUM>-<NUM> for various periods of time to inject a desired amount of one or more chemical products into the flush manifold <NUM>. Once the mixture of chemicals defined by the dispensing application has been dispensed, the controller may open the selector valve <NUM> of flush eductor <NUM> to flush the flush manifold <NUM> with diluent for a period of time sufficient to flush each dispensed solution to the point of use.

By way of example, in a conventional dispensing system, two chemicals may come into contact as follows. The controller opens the selector valve of an eductor to dispense chemical A, which fills the flush manifold and the dispense line with a solution containing chemical A. After the correct amount of chemical A has been delivered to the flush manifold, the controller closes the selector valve. This may cause the pressure in the flush manifold to spike downward - and potentially go negative - as the momentum of the previously dispensed solution causes the solution to continue to flow through the dispense line, thereby pulling a vacuum on the flush manifold.

At this point, the controller may open the selector valve for the flush eductor, which pressurizes the flush manifold with diluent. Empirical data indicates that the pressure in the flush manifold may spike to approximately <NUM> bar in response to the controller flushing the flush manifold. This pressure may compress any air in the inactive eductors, thereby allowing any chemical solution remaining in the flush manifold to enter the eductors. This effect was determined experimentally using clear eductors in which a solution in the flush manifold was seen to rise to a level at which it occupied approximately <NUM>% of the volume of the eductor. Unexpectedly, it has been further determined that the solution in the flush manifold rises to level in each eductor in proportion to the distance of the eductor from the last eductor used to dispense a chemical solution. Thus, the level rises the most in the eductor adjacent to the most recently activated eductor.

The phenomenon wherein the level rises in accordance to the distance from the most recently used eductor may be due to the last eductor used being relatively full of incompressible solution rather than compressible air as may be found in eductors that have had time to drain. The same phenomenon may occur when one chemical is dispensed immediately following another. In either case, the size of the pressure spike may also depend on the flow rate of the subsequent dispensing operation. Thus, activation of high flow eductors and/or flush eductors may generate higher pressure spikes in the flush manifold than low flow eductors. If the level of the dispense line rises above the level of the flush manifold at any point between the flush manifold and the point of use, this can also increase the pressure in the flush manifold as compared to dispense lines that remain below the flush manifold. In any case, when a selector valve opens, any solution present in the manifold may cause the pressure to increase as compared to when the flush manifold is empty and/or open to the atmosphere.

The check valves <NUM>-<NUM> may be configured to prevent solutions being dispensed by one or more of eductors <NUM>-<NUM> from back-flowing into the remaining inactive eductors as described above. This may prevent any of the chemicals dispensed by one eductor from entering one or more of the other eductors from the flush manifold <NUM>. Advantageously, the check valves <NUM>-<NUM> may prevent different chemicals from coming into contact within the eductors <NUM>-<NUM> and plugging the venturi orifices thereof.

The check valves <NUM>-<NUM> may also provide a dynamic flood ring that keeps their respective eductor <NUM>-<NUM> in a constantly primed or "flooded" state by preventing solution from draining out of the eductor between activations. In addition, the check valves <NUM>-<NUM> may prevent air from entering the eductor and drying out any remaining chemical solutions, which could create residue inside the eductors <NUM>-<NUM>. By independently varying the resistance provided to the flow of fluids through the eductor, the check valves <NUM>-<NUM> may provide more efficient operation than would be provided by fixed flood ring.

Still further, the check valves <NUM>-<NUM> may provide an additional benefit of creating a dynamic barrier that opens when the eductor <NUM>-<NUM> is activated and closes when the eductor <NUM>-<NUM> is idle to prevent contamination. Check valves <NUM>-<NUM> may be implemented as cartridges that can be added to existing systems as a separate part, or the check valves <NUM>-<NUM> may be integrated into the eductors <NUM>-<NUM> and/or flush manifold <NUM>.

<FIG> is a cross-sectional view depicting additional details of the flush eductor <NUM>, dispensing eductor <NUM>, and module <NUM>. Each eductor <NUM>, <NUM> includes a venturi <NUM>, a converging passage <NUM> that fluidically couples the venturi <NUM> to the inlet port <NUM>, <NUM>, a diverging passage <NUM> that includes a diffuser <NUM> and fluidically couples the venturi <NUM> to the discharge port <NUM>-<NUM>, and a passage <NUM> that fluidically couples the venturi <NUM> to the pickup port <NUM>, <NUM>. The module <NUM> may include a tapered outlet <NUM> that includes one or more circumferential grooves <NUM>, <NUM>, a tapered inlet <NUM> including one or more flexible rings <NUM>, <NUM>, and one or more openings <NUM>, <NUM> configured to receive the eductor <NUM>, <NUM> and/or check valve <NUM>. The tapered inlet <NUM> may be configured to receive and form a fluid-tight seal with the tapered outlet of another module. The flexible rings <NUM>, <NUM> may be configured to engage the circumferential grooves of the received tapered outlet so that the received tapered outlet is held position with respect to the module receiving the outlet.

<FIG> is a cross-sectional view depicting additional details of an exemplary embodiment of the check valve <NUM>. The check valve <NUM> may include a barrel <NUM> having an upstream portion <NUM> configured to receive the discharge port <NUM> of eductor <NUM> and a downstream portion <NUM> configured to engage the opening <NUM> of module <NUM>. The upstream portion <NUM> of barrel <NUM> may define an upstream chamber <NUM> and the downstream portion <NUM> of barrel <NUM> may define a downstream chamber <NUM>. The inner surface of barrel <NUM> may include a shoulder <NUM> between the upstream and downstream chambers <NUM>, <NUM> that provides support for a valve seat <NUM>. The valve seat <NUM> may be held in place against the shoulder <NUM> by a valve seat retainer <NUM> and may define an opening <NUM> between the upstream and downstream chambers <NUM>, <NUM>. In an alternative embodiment of the invention, the shoulder <NUM> may be configured to define the opening <NUM>, in which case the valve seat <NUM> and valve seat retainer <NUM> may be omitted.

A closing member <NUM> (e.g., a ball) may be urged into engagement with the opening <NUM> by an elastic member <NUM> (e.g., a spring). The elastic member <NUM> may be configured to maintain the closing member <NUM> in contact with the opening <NUM> when fluids are not being dispensed through the check valve <NUM>, and to allow the closing member <NUM> to move away from the opening <NUM> when fluids are being dispensed through the check valve <NUM>.

The eductor <NUM> may operate most efficiently when it is flooded, e.g., when the diffuser <NUM> is filled with solution. A flooded diffuser <NUM> may slow the velocity of the incoming diluent <NUM> as compared to a dry or empty diffuser, thereby ensuring a sufficient pressure drop across the eductor <NUM> to draw chemical product <NUM>, <NUM> into the pickup port <NUM>. By causing the closing member <NUM> to seal off the opening <NUM> when there is insufficient flow through the eductor <NUM>, the elastic member <NUM> may enable the check valve <NUM> to operate as a dynamic flood ring that provides varying resistance to flow. The elastic member <NUM> may be held in place by a support <NUM> that includes a support surface <NUM>. The support <NUM> may locate the elastic member <NUM> within the downstream chamber <NUM> of barrel <NUM>. The support surface <NUM> of support <NUM> may be configured to hold the closing member <NUM> in a fixed open position when the flow of fluid through the eductor <NUM> exceeds a threshold value. The support surface <NUM> may thereby prevent damage to the elastic member <NUM> during dispensing operations. In the event air is present in the inlet manifold, the elastic member <NUM> may allow the air to flowing through the eductor <NUM> to open the check valve <NUM> slightly. The subsequent flow of liquid may then fully open the check valve <NUM> to provide maximum flow.

Adding check valves <NUM>-<NUM> between the dispensing eductors <NUM>-<NUM> and the flush manifold <NUM> may provide several advantages over conventional systems. For example, the check valves <NUM>-<NUM> provide a fluidic barrier between the dispensing eductors <NUM>-<NUM> and the flush manifold <NUM>. This barrier may prevent mixing of dissimilar chemicals in the venturi <NUM>, converging passage <NUM>, diffuser <NUM>, diverging passage <NUM>, or any other portions of the eductors <NUM>-<NUM>, thereby reducing the potential for clogging as described above. In addition, by preventing the diffuser <NUM> from drying out between chemical dispense stages and/or dispensing operations, the check valves <NUM>-<NUM> may prevent mineral salts and/or dissolved chemicals in the diluent from adhering to the inner surfaces of the eductors <NUM>-<NUM>. Because further chemical products may adhere to these deposits, eventually building up and clogging the eductor <NUM>-<NUM>, the check valves <NUM>-<NUM> may also reduce the potential for clogs due to the eductor <NUM>-<NUM> drying out between dispensing operations.

The dynamic flood ring feature of check valves <NUM>-<NUM> may improve the accuracy of dispensing processes by maintaining the eductor <NUM>-<NUM> in a wet state. When an eductor <NUM>-<NUM> is activated in a conventional dispensing system, there may be an initial period during which the eductor <NUM>-<NUM> does not generate suction at the pickup port <NUM>-<NUM>. This failure to generate suction is believed to be due to a lack of liquid in the diffuser <NUM> at the beginning of the dispense stage. Thus, until enough diluent <NUM> has passed through the converging passage <NUM> to flood the diffuser <NUM>, the eductor may fail to inject chemicals into the diluent <NUM>. Depending on the design of the eductor <NUM>-<NUM>, this flooding process can take <NUM> to <NUM> milliseconds. By isolating the diverging passage <NUM> from the flush manifold <NUM> when the eductor <NUM>-<NUM> is inactive, the check valve <NUM>-<NUM> may keep the diffuser <NUM> primed by preventing the chemical solution from draining out of the diverging passage after the selector valve <NUM>-<NUM> is deactivated. This may result in the diffuser <NUM> reaching a flooded state sooner after activation of the selector valve <NUM>-<NUM> than in dispensing systems lacking this feature. This in turn may result in the eductor <NUM>-<NUM> drawing chemicals and injecting them into the diluent sooner and more consistently than in conventional eductor-based dispensing systems.

The check valves <NUM>-<NUM> may also reduce leaks caused by positive pressure at the outlet <NUM> of the flush manifold <NUM>. For example, in cases where the dispense line <NUM> is routed above the dispenser <NUM>, there is a potential for the dispense line <NUM> to remain full of diluent <NUM> after flushing. Absent the check valves <NUM>-<NUM>, if one of the check valves <NUM> coupling the feed line to the pickup port of an eductor is remove during a service call, the contents of the dispense line <NUM> may drain back into the eductor and spill onto the floor. This issue may be eliminated with the use of check valves <NUM>-<NUM>. Additional advantages of the check valves <NUM>-<NUM> may include separation of pressure zones during flushing operations.

In general, the routines executed to implement the embodiments of the invention, whether implemented as part of an operating system or a specific application, component, program, object, module or sequence of instructions, or a subset thereof, may be referred to herein as "computer program code," or simply "program code. " Program code typically comprises computer-readable instructions that are resident at various times in various memory and storage devices in a computer and that, when read and executed by one or more processors in a computer, cause that computer to perform the operations necessary to execute operations and/or elements embodying the various aspects of the embodiments of the invention. Computer-readable program instructions for carrying out operations of the embodiments of the invention may be, for example, assembly language or either source code or object code written in any combination of one or more programming languages.

Various program code described herein may be identified based upon the application within which it is implemented in specific embodiments of the invention. However, it should be appreciated that any program nomenclature which follows is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Furthermore, given the generally endless number of manners in which computer programs may be organized into routines, procedures, methods, modules, objects, and the like, as well as the various manners in which program functionality may be allocated among various software layers that are resident within a typical computer (e.g., operating systems, libraries, API's, applications, applets, etc.), it should be appreciated that the embodiments of the invention are not limited to the specific organization and allocation of program functionality described herein.

The program code embodied in any of the applications/modules described herein is capable of being individually or collectively distributed as a program product in a variety of different forms. In particular, the program code may be distributed using a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to carry out aspects of the embodiments of the invention.

Computer-readable storage media, which is inherently non-transitory, may include volatile and non-volatile, and removable and non-removable tangible media implemented in any method or technology for storage of data, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, portable compact disc read-only memory (CD-ROM), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired data and which can be read by a computer. A computer-readable storage medium should not be construed as transitory signals per se (e.g., radio waves or other propagating electromagnetic waves, electromagnetic waves propagating through a transmission media such as a waveguide, or electrical signals transmitted through a wire). Computer-readable program instructions may be downloaded to a computer, another type of programmable data processing apparatus, or another device from a computer-readable storage medium or to an external computer or external storage device via a network.

Computer-readable program instructions stored in a computer-readable medium may be used to direct a computer, other types of programmable data processing apparatuses, or other devices to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions that implement the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams. The computer program instructions may be provided to one or more processors of a general-purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the one or more processors, cause a series of computations to be performed to implement the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams.

In certain alternative embodiments, the functions, acts, and/or operations specified in the flow-charts, sequence diagrams, and/or block diagrams may be re-ordered, processed serially, and/or processed concurrently consistent with embodiments of the invention. Moreover, any of the flow-charts, sequence diagrams, and/or block diagrams may include more or fewer blocks than those illustrated consistent with embodiments of the invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the invention. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof. Furthermore, to the extent that the terms "includes", "having", "has", "with", "comprised of', or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprising".

Claim 1:
A portion of a dispensing system comprising:
a flush manifold (<NUM>) including a plurality of intake ports (<NUM>-<NUM>);
a plurality of eductors (<NUM>-<NUM>), each eductor connected to a respective one of the plurality of intake ports (<NUM>-<NUM>), each eductor having an inlet port (<NUM>-<NUM>) that is selectively fluidically coupled to a source of a diluent (<NUM>), a pickup port (<NUM>-<NUM>) fluidically coupled to a source of a chemical product (<NUM>, <NUM>), and a discharge port (<NUM>-<NUM>) configured to discharge a chemical solution in response to the diluent (<NUM>) being coupled to the inlet port (<NUM>-<NUM>); the portion of a dispensing system being characterised in that it further comprises:
a check valve (<NUM>) coupling the discharge port (<NUM>-<NUM>) of one of the eductors (<NUM>-<NUM>) to one of the intake ports (<NUM>-<NUM>) of the flush manifold (<NUM>).