Abstract: A method of controlling and operating a fluid dispensing apparatus is provided which modifies a tool speed signal from a robot and generates a corrected signal to a dispenser nozzle flow controller to compensate for non-linear flow characteristics of fluids, such as non-Newtonian adhesive fluids, to maintain uniform bead size as the tool speed varies. The corrected tool speed signal is generated by computing the ideal flow for the tool speed, comparing the computed flow with actual flow data stored in memory using linear interpolation of data between the stored values, and generating a control signal modified in accordance with the comparison. The stored data is acquired by operation of the apparatus in a calibration mode wherein a series of standard signals is sent to the fluid controller while the actual flow at each signal level is measured and stored in a table. The method corrects for non-linear flow phenomena such as that known as the shear-thinning effect that is flow rate dependent.

Abstract: A method and apparatus for forming and dispensing a coating material formulation or solution containing a liquid coating composition and a fluid diluent such as a supercritical fluid comprises a supply for the liquid coating composition, a supply for the fluid diluent, a mixer for combining the two components to form the coating material solution or formulation, and a control system for monitoring a parameter of the formulation which can be correlated to the fluid diluent content and/or liquid coating composition content of the formulation, and for monitoring the pressure of the formulation at selected locations within the system.

Abstract: The monitoring of energy radiating from a heated material, such as a hot melt adhesive, dispensed onto a substrate may be accomplished by an infrared sensor. The wand of the infrared sensor is located downstream of the dispensed material for receiving the radiant energy. The wand is provided with internal air for cooling and for providing laminar air flow in the vicinity of the lens to prevent the accumulation of airborne contaminants on the lens. The wand is also provided with a light aiming device.

Abstract: A method of monitoring and/or controlling the motion of a moving coating material dispensing pattern or fiber is provided with a monitor that senses a medium such as sound, light or other form of energy near the space between the dispensing device nozzle and a substrate, and a monitoring signal is generated. Information relating to the pattern motion is extracted, and an output signal is generated representative of characteristics of the motion of the pattern in the space. One or more transducers are used to extract the information, which is analyzed, preferably by comparison of a frequency spectrum of the signal with a spectrum of standard signal, to detect deviations in the system operation from desired criteria. Optionally, the output signal is used to control parameters of the system. In another embodiment, plural spaced transducers detect the phase or orientation of the moving pattern and remove background noise, by inverting, summing, multiplying, and otherwise combining the signals.

Abstract: A method and apparatus for forming and dispensing a coating material formulation or solution containing a liquid coating composition and a fluid diluent such as a supercritical fluid comprises a supply for the liquid coating composition, a supply for the fluid diluent, a mixer for combining the two components to form the coating material solution or formulation, and a control system for monitoring a parameter of the formulation which can be correlated to the fluid diluent content and/or liquid coating composition content of the formulation, and for monitoring the pressure of the formulation at selected locations within the system.

Abstract: A pressure transducer (58) generates an instantaneous pressure of a pressurized liquid, such as an adhesive, sealant, or caulk, being dispensed from a dispenser (52). The signal is received by a filter for filtering out non-bubble pressure disturbances. The filter includes comparators (106, 108); detection circuitry (112, 120) and timers (116, 124) or counters. An alarm indicating the passing of a bubble is indicated in response to signals which pass both the filters.

Abstract: A fluid dispensing apparatus having a controller which operates to modify a tool speed signal from a robot and to generate a corrected signal to the dispenser nozzle flow controller which compensates for non-linear flow characteristics of fluids, such as non-Newtonian adhesive fluids, to maintain uniform bead size as the tool speed varies. The corrected tool speed signal is generated by computing the ideal flow for the tool speed signaled, comparing the computed flow with actual flow data stored in a memory using linear interpolation of data between the stored values, and generating a control signal modified in accordance with the comparison. The stored data is acquired by operation in a calibration mode wherein a series of standard signals is sent to the fluid controller while the actual flow at each signal level is measured and stored in a table. The method of operation corrects non-linear flow phenomena such as the shear-thinning effect.

Abstract: A system for monitoring energy radiant from a material dispensed onto a substrate. As disclosed, an infrared sensor is positioned to receive infrared energy radiated by a substrate and by a heated adhesive applied to the substrate, with the resistance of the sensor varying in dependence upon the amount of infrared energy received. An amplifier has an input capacitively coupled to the sensor, and the voltage at the amplifier input varies in dependence upon the resistance of the sensor. The output voltage of the amplifier varies in dependence upon the amplifier input voltage, and hence upon the amount of infrared energy reaching the sensor. In order to prevent inaccuracies in the amplifier output signal due to, for example, temperature-related resistance variations of the sensor, the amplifier input is grounded during intervals when the sensor receives infrared energy from the substrate and ungrounded shortly before the sensor begins to receive infrared energy from the heated adhesive.

Abstract: Apparatus and method for dispensing fluid materials wherein the fluid is discharged from a nozzle at a rate controlled by a metering valve having a seat and a stem moveable with respect to the seat to modulate the flow. A servo-actuator connected in a feedback control loop is used to position the valve stem with respect to its seat in accordance with a control signal. The control signal is derived in accordance with the difference between a driving signal representing a desired flow rate and the sum of a pair of feedback signals. One feedback signal represents the actual flow rate while the other feedback signal is correlated to both the relative velocity and position of the stem with respect to the seat. The position-dependent velocity signal is generated by a transducer comprising a magnet and a coil influencable by the field of the magnet as the magnet and coil move relative one another.

Abstract: A system for monitoring energy radiant from a material dispensed onto a substrate. As disclosed, an infrared sensor is positioned to receive infrared energy radiated by a substrate and by a heated adhesive applied to the substrate, with the resistance of the sensor varying in dependence upon the amount of infrared energy received. An amplifier has an input capacitively coupled to the sensor, and the voltage at the amplifier input varies in dependence upon the resistance of the sensor. The output voltage of the amplifier varies in dependence upon the amplifier input voltage, and hence upon the amount of infrared energy reaching the sensor. In order to prevent inaccuracies in the amplifier output signal due to, for example, temperature-related resistance variations of the sensor, the amplifier input is grounded during intervals when the sensor receives infrared energy from the substrate and ungrounded shortly before the sensor begins to receive infrared energy from the heated adhesive.

Abstract: A dispenser for fluid under pressure has a sensor affixed to it to sense the pressure of the fluid proximate the dispenser discharge opening to generate a pressure reflective signal. A comparator is connected to receive the pressure reflective signal to compare the pressure signal with a preselected band of pressure values which are selected to reflect operating pressures when the dispenser discharge opening is opened. The comparator generates a malfunction signal when the sensed pressure signal is outside the preselected band.

Abstract: A pressure monitoring system monitors the pressure of hot melt adhesive in a dispenser in an adhesive dispensing system. The dispenser includes a valve and the dispensing system further includes a controller for opening and closing the valve for dispensing pressurized hot melt adhesive from the dispenser. The pressure monitoring system includes a sensor circuit which develops an electrical pressure signal reflective of the pressure of adhesive in the dispenser and a pressure monitor circuit which monitors the electrical pressure signal when the dispenser valve is open. A pulse masking circuit is interposed between the pressure sensor circuit and the pressure monitor circuit to modify the signal produced by the pressure sensor circuit to mask out a transient leading edge, reduced pressure pulse appearing in the electrical pressure signal each time the valve is opened.

Abstract: A scanning display system for providing a sequential display of a number of temperature signal inputs. The inputs are coupled through a multiplexer to sequentially produce single output signals, which are in turn scaled and displayed in a digital display. Some of the inputs to the multiplexer may not be used, leaving certain unused inputs which are sequentially coupled to the output of the multiplexer. The multiplexer normally advances through the inputs at a particular clocking rate, as determined by a first clocking signal, at a selected frequency. The scanning display system recognizes the coupling of an unused input to the multiplexer output and advances the multiplexer using a second, higher frequency, clocking signal until the next used input is reached. In this way, only temperature inputs for used channels are displayed in the digital temperature display. A manually operated switch is also provided to advance the multiplexer through the sequence of input temperature signals.

Abstract: A motor drive for a hot melt adhesive pump is maintained in an inoperative condition until the adhesive has heated sufficiently to permit free operation of the motor. The adhesive is received in a container supported upon a heater which is activated to heat the container and the adhesive therein. The output of a proportional control for the heater, which is responsive to the container temperature, is monitored. The output of the proportional control, when the container temperature is near a set point temperature indicative of a desired heated condition for the adhesive, is an intermittent signal. In one form of the invention, the intermittent signal is electrically integrated to produce an interlock release pulse permitting operation of the motor. In a second form of the invention, a thermal relay is coupled to a source of electrical power through a switching circuit, which permits power to be coupled to the thermal relay during the intermittent off times of the heater.

Abstract: A system for controlling the temperature at a location which is heated by a heater. The heater is intermittently energized by a source of electrical power in response to control signals from a temperature control circuit. The temperature control circuit includes a comparator-amplifier having one input coupled to a sensed temperature signal. The other input to the comparator-amplifier is a set point temperature level. The sensed temperature signal is produced by a bridge circuit including a temperature sensor at the location which is being heated. The comparator-amplifier includes a feedback network to establish a pulse output of a certain frequency when the two inputs are equal. In order to expand the operating band of the comparator-amplifier, an a-c voltage is introduced superimposed on the set point input.

Abstract: A solenoid driver circuit for a solenoid-operated fluid dispenser in which a valve is operable to dispense a fluid under the control of the solenoid. The driver circuit receives externally applied turn-on and turn-off signals and energizes the solenoid in response to these signals. The driver circuit is responsive to a turn-on signal to couple a pull-in voltage across the solenoid to pull in a solenoid valve armature. The driver circuit is also operable to sense the level of current in the solenoid. When the solenoid current reaches a preset peak current level, the pull-in voltage is removed from the solenoid and replaced by a hold-in voltage. When the hold-in voltage is applied to the solenoid, the driver circuit is operable to control the level of the hold-in voltage in order to maintain a preselected hold-in current in the solenoid. The driver circuit controls the solenoid current so that it makes a gradual transition from the peak solenoid current level to a steady state hold-in current level.

Abstract: A projector for motion picture film includes a servo motor which is controlled to advance film frame by frame to a projection station. A capstan on each side of the projection station is controlled to maintain film loops of substantially constant size and an associated reel motor delivers film to and takes film from each capstan. Each associated capstan and reel motor are controlled so as to maintain substantially constant tension on the film. A film guide defines the projection station and also includes provision for masking peripheral areas of each frame. Each capstan and an associated pinch roller are designed so as to eliminate creeping of film from between the two. A circuit for controlling the reel motors is arranged to permit fast winding of film directly from one reel to the other with an automatic braking feature.