Abstract: A system for maintaining constant pressure, such as at a mosquito fogging nozzle, by electronically controlling the speed of an engine that is coupled to a blower. A pressure sensor measures the pressure provided by the blower and provides a pressure signal to the electronic engine controller. The engine controller is of the proportional-integral (PI) type and utilizes pulse-width modulation (PWM) techniques to control an electromechanical actuator attached to the throttle of the engine to vary the engine speed. Constant pressure is maintained despite changes in the ambient temperature, humidity and barometric pressure. A safety circuit prevents engine over-speed if the pressure signal is lost. An over-speed circuit monitors and controls the engine speed at higher RPMs.

Abstract: An improved cryogenic compressor with piston position sensing is disclosed. Precision optical encoders using incremental or absolute encoding are incorporated into a compressor to allow for accurate position sensing of moving elements within the compressor. Appropriate electronic circuitry is used to interpret the position data to allow the user modify the frequency and stroke of the piston within the compressor. The invention may be used in systems with multiple compressor pistons or for position data for balance weights or displacers in a cryogenic refrigeration system.

Abstract: A pressure sensor subsystem measures the pressure within a fuel pump and outputs an under-pressure signal when the measured pressure is below a predetermined threshold pressure value. A temperature sensor subsystem measures the temperature within the fuel pump and outputs an over-temperature signal when the measured temperature is above a predetermined threshold temperature value. A timing circuit monitors the pressure sensor subsystem and the temperature sensor subsystem for output of the under-pressure and over-temperature signals and outputs a pump disconnect signal when at least one of the signals is output for a prescribed time duration. A power controller disengages power from the pump upon output of a pump disconnect signal by the timing circuit.

Abstract: Hydraulically actuated aerial lift trucks typically have a primary hydraulic pump system driven by the vehicle's engine and a backup pump system driven by a direct current motor. Due to infrequent use of such motors, they are vulnerable to failure due to corrosion of the brush/commutator interface or seizing of the motor bearings. A remote power unit is provided to periodically run the back up motor for brief periods to maintain the motor in running condition. Voltage levels across the motor terminals are monitored for correspondence to failure indicating levels.

Abstract: A transducer calibration apparatus and method for transforming both previously established transducer parameters for a transducer calibrated to a first target object material and measured transducer parameters for the transducer monitoring a second different target object material into a calibration parameter and transforming the output of the transducer and thus, the use of the transducer, from the first target object material used to calibrate the transducer to the second different target object material being subsequently monitored by the transducer by linearizing the output of the transducer into gap values as a function of the calculated calibration parameter and then, generating alarms based on the linearized output of the transducer exceeding established limits and using the alarms to automatically shut down a machine being monitored by the transducer and/or automatically annunciate machine problems to personnel.

Abstract: A multifan-equipped apparatus in which a plurality of objects mounted are controllably cooled by blowing air using a fan-unit assembly composed of a plurality of fan units. The plural fan units are divided into a plurality of groups; the fan units in the same group are arranged in a queue. And one of the fan units of each group is a master fan unit that is autonomically adjustable in revolutions per minute (rpm) in accordance with a current apparatus-environment temperature and serves to make a tuning control on the rpm of at least one of the remaining fan units in the same group so as to adjust the rpm to a first estimated value corresponding to the autonomic-adjusted rpm of the master fan unit.

Abstract: A reciprocating pump which is capable of detecting abnormalities in the sucking and discharging of fluid, such as the exhaustion of oil or the clogging of oil on the discharge side, by making use of detecting means which is inexpensive and relatively simple in structure and which can be operated without being detrimentally influenced by the bubbles that may be included in the fluid, while making it possible to minimize the noise generated by external vibrations. In this reciprocating pump, where the sucking and discharging of fluid are effected by making use of a reciprocating member, malfunction-detecting means formed of a piezoelectric element is provided for detecting a pressure fluctuation on a discharge side of the pump, and the pressure fluctuation of fluid being delivered from an discharging port is transmitted via a rigid pressure-receiving member to the piezoelectric element.

Abstract: A constant flow of air through a personal air sampler is provided regardless of changes in the air flow path, by altering the pump speed as a function of the power taken by the pump. The characteristics of the pump are precalibrated to provide a constant used together with the square of the voltage appearing across the motor armature coils (applied voltage minus back Emf), which reflects the power currently used, to adjust the motor speed and thus provide a constant flow of air under changing conditions of resistance.

Abstract: The invention relates to the use of variable speed control of the cooling fan on a variable speed oil-injected screw compressor. A screw compressor (11) comprises at least one stage of compression, each with a pair of rotors, variable speed compressor drive means (12), an oil reclaimer (13) from the compressed air and cooling apparatus (17) for cooling the oil extracted from the compressed air. The cooling apparatus comprises a heat exchange device and a fan (18) driven by a motor (19) which can be run at different speeds.

Abstract: A pump apparatus, which comprises: (a) a tubular portion comprising an electroactive polymer actuator that expands and contracts an inner volume of the tubular portion based upon received control signals; and (b) a control unit electrically coupled to the electroactive polymer actuator and sending control signals to the actuator. The pump apparatus can further include at least one valve that is in fluid communication with the inner volume of the tubular portion. The pump apparatus can be used, for example, as a heart-lung bypass pump apparatus. Also disclosed herein is a method of providing circulatory support for a patent.

Abstract: Motor speed, motor amps, float position and elapsed run time are monitored to determine whether a sump pump is in a normal condition, a jammed condition, an inadequate pumping rate condition, a dry running condition or a stuck float condition. A processor is configured to increase the motor speed in response to an inadequate pumping rate condition, and to rapidly energize the motor clockwise and counterclockwise in response to a jammed condition or a stuck float condition. The processor provides signals to a display for displaying information about the condition that the pump is in. The pump is set up to receive power from either an AC power source or a battery power source. Availability of the AC power source is monitored and the pump is switched to operate from the battery power source when AC power is unavailable.

Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the sensor output levels to declare when an occlusion exists.

Abstract: A closed-loop blower includes a blower assembly having a motorized fan that draws ambient air in through an inlet and exhausts air out an outlet. A control circuit is coupled to the motorized fan and a pressure sensing device near the outlet measures pressure of the exhaust air and generates a pressure signal. The control circuit receives the pressure signal and adjusts the speed of the motorized fan to obtain a desired pressure at the outlet. Temperature and motor speed readings may also be detected and input to the control circuit to adjust the speed of the motor and thus the fan. An input device may be provided to adjust the desired pressure values or the control circuit may be programmed with the desired value.

Abstract: In a fire pump adapted to force out the water, which is pumped from a water source, from a nozzle provided at a front end portion of a delivery hose, a nozzle control unit 8 adapted to control the fire pump remotely is provided in the vicinity of the nozzle. The nozzle control unit 8 is connected to a body of the fire pump 1 by power source lines 33. On the nozzle control unit 8, a control instruction unit for instructing an operating mode of the pump 1, and a numerical value display unit for displaying the operation condition of the fire pump are provided. The transmitting and receiving of an operation control signal and a condition display signal are done between the pump 1 and nozzle control unit 8 by power line communication via the power source lines 33, whereby the operation condition of the pump 1 is feedback displayed in real time in response to a control operation of a nozzle operator.

Abstract: A method and apparatus which provides a pressure sensor and/or temperature sensor connected to the low pressure side of a refrigeration system, or the discharge line of a scroll compressor. When the scroll compressor rotates backward, the change of pressure or temperature immediately sends a signal to work with a time-delay relay and a normally closed relay to immediately cut off the electrical power supply to the compressor. Thus, causing the scroll compressor to stop rotating in the undesirable direction.

Abstract: An apparatus and a method for controlling operation of a linear motor compressor, by which a linear motor compressor can operate always in an optimum condition by coping with the load variation due to changes in a refrigerator and the circumstances. In more detail, a current peak value at TDC=0 is detected by comparing a current applied to the linear motor compressor with a formerly detected current, and accordingly the linear motor compressor is operated by a switching control signal generated according to a duty-ratio corresponding to the current peak value.

Abstract: An apparatus and a method for controlling operation of a linear compressor uses a pattern recognition for operating a compressor at an optimum efficiency by recognizing a trace in a graph about relation between a current and a displacement as a pattern and sensing variation of the pattern.

Abstract: A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Abstract: A system for remote-controlling a fire pump with a simple wiring construction is provided, being capable of conducting various kinds of control and display. The fire pump control system has an engine, a fire pump, an internal control apparatus, at least one external control apparatus located away from the fire pump including the internal control apparatus, and a twisted pair line for connecting the external control apparatus with the internal control apparatus. The internal and external control apparatuses form a network through the twisted pair line so as to control the fire pump through telecommunications from the external control apparatus. This network uses a p-CSMA system for communicating data, so that a high level of remote control can be carried out, with monitoring an operation state of the fire pump.

Abstract: A thermostat is positioned within a scroll compressor such that a thermostat switch is positioned in the non-orbiting scroll, and a body of the thermostat extends through the crankcase. The thermostat communicates with a heater associated with a motor protector circuit. Current is directed to the heater causing the heater to more promptly stop operation of the scroll compressor. A bias element holds the thermostat securely within the crankcase and non-orbiting scroll such that it will not rattle during operation. Several embodiments of the thermostat are disclosed.

Abstract: There is provided an autonomous inverter-driven hydraulic unit in which a command pressure and command flow rate do not need to be inputted from outside and a pressure and flow rate can be autonomously controlled without requiring any input signal wire. A target horsepower calculation unit 25 of a controller 11 judges which of a plurality of regions a point representing a present operating state belongs to and calculates a target horsepower represented by a point on a target pressure-flow rate characteristic line based on the present pressure and present flow rate. A comparison unit 28 calculates a deviation of this target horsepower and a present horsepower received from a present horsepower calculation unit 26, inputs a control signal representing this deviation to the inverter 3 and controls a rotational number of a variable-speed motor 2 so that the present horsepower coincides with the target horsepower.

Abstract: An apparatus for controlling an operation of a linear compressor includes: a sensorless circuit unit for detecting a current and a voltage applied to a linear compressor and outputting a work operation value corresponding to them; a stroke controller for receiving the work operation value and outputting a switching control signal corresponding to a variation amount of the work operation value; and an electric circuit unit for receiving the switching control signal from the stroke controller and outputting a certain voltage to the linear compressor, accordingly, a TDC of the piston in consideration of an error due to the nonlinear characteristic can be controlled, and thus, an operation efficiency of the linear compressor can be improved.

Abstract: In an apparatus and a method for controlling a linear compressor, an apparatus for controlling a linear compressor includes a linear compressor adjusting a refrigerating capacity by a stroke voltage according to a stroke reference value, a current detecting unit detecting a current applied to the linear compressor, a work operation unit generating a work operation signal by integrating a current detected from the current detecting unit, a suction/discharge pressure difference storing unit storing a suction/discharge pressure difference according to the work operation signal, a microcomputer outputting a switching control signal according to the work operation signal and displaying the suction/discharge pressure difference according to the work operation signal, and an electric circuit unit controlling the linear compressor in accordance with the switching control signal.

Abstract: In an apparatus and a method for controlling operation of a linear compressor, operation of a linear compressor is controlled by finding each inflection point as a TDC (top dead center) is 0 by using a current and a displacement vector generated in the linear compressor, determining a duty ratio on the basis of the inflection point and generating a switching control signal according to the determined duty ratio.

Abstract: In an apparatus and a method for controlling operation of a reciprocating compressor which is capable of operating a compressor stably by detecting a phase difference and using an inflection point of the phase difference, an apparatus and a method for controlling operation of a reciprocating compressor including an electric circuit unit operating a reciprocating compressor by varying a stroke with motion of a piston, a phase difference detecting unit detecting a phase difference of a current and a voltage from the electric circuit unit, a phase inflection point detecting unit detecting a phase inflection point by being inputted the phase difference, and a stroke controlling unit being inputted the detected phase inflection point from the phase inflection point detecting unit and applying a voltage, to the electric circuit unit in order to make the stroke correspond to the phase inflection point can control a TDC of a piston regardless of load variation, improve an operation efficiency of a reciprocating compr

Abstract: A method and apparatus for achieving constant air flow rate economically utilizes an induction blower motor with control settings determining the motor excitation voltage. A memory stores, for a variety of motor speeds, a graph of the speeds plotted against a proportionality constant of flow rate to fan speed for the selected motor system on one axis and motor control settings on the other axis. The only monitoring necessary to achieve the constant flow rate is thus the sensing of fan rotational speed. The measured fan speed is compared against the proportionality constant needed for the selected constant air flow rate and a motor excitation voltage is derived to achieve that proportionality constant. When the system load changes significantly, thereby causing significant fan speed change, a cascaded control loop is used whereby the speed changed induced by each control voltage adjustment is monitored until the desired constant flow rate is again attained at the new load level.

Abstract: A scroll compressor is provided with a motor protector mounted at a location remote from the motor. The motor protector is of the sort which operates to stop operation of the motor both when the temperatures in the scroll compressor increases, and when the electrical characteristics of the power supplied to the motor depart from those from which are expected. Preferably, the motor protector is mounted in the non-orbiting scroll. Further, the invention includes means to increase the sensitivity of this motor protector to conditions indicative of an outdoor fan failure. In several embodiments, these means include a valve which opens to communicate hot discharge pressure refrigerant over the valve. In one other embodiment, this means is a heat sink operable to take heat away from the motor protector. In this last embodiment, when the volume flow of refrigerant decreases, the amount of heat taken away also decreases.

Abstract: An electronic control system dynamically varies the output capacity of a compressor by controlling plural valves associated with the compressor to provide pressurized air to a distribution system at an appropriate rate. The control system operates in any of three modes for standalone operation, including continuous run, auto/dual pressure band, and target pressure modes. In the first two modes, pressure bands are dynamically calculated based on load and unload values entered by an operator. These electronic control systems can also be connected in a peer-to-peer network to coordinate control of up to 16 compressors feeding the same distribution system, so as to maintain a desired target pressure in the system. A modem connected to the system supports remote diagnostics, monitoring, and control. Specialized startup, operating, and shutdown diagnostic algorithms prevent damage to the compressor and avert unsafe operating conditions.

Abstract: A liquid pump and controller with separate pump activation and deactivation mechanisms that are both closed detector devices is provided. The pump activation mechanism includes a float device that activates a pump motor when water within a housing of the pump reaches a high water level. The pump deactivation mechanism includes a sensor that detects the load on the pump motor and deactivates it when the sensed load indicates that the water within the pump housing has reached a low water level.

Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the senor output levels to declare when an occlusion exists.

Abstract: A multi-stage blowdown valve is provided that uses a single control signal to simultaneously decompress the interstage and the second stage in a compressor system. The valve uses a series of sliding spools located linearly within a single bore to either prevent or allow fluid communication between two isolated passageways each having an inlet port and a discharge port. The valve, when used as a two stage blowdown valve in a multi-stage compressor system, can prevent compressor failure from occurring by ensuring that both the interstage and the second stages are decompressed. not only the interstage.

Abstract: An electronic control system is disclosed to control and to prevent damage to a standalone or a network of oil free, two stage compressor packages. The electronic control system uses pressure and temperature sensors to detect actual shutdown conditions or predict shutdown conditions based on the operating state of the compressor package and the current temperatures or pressures of the air at strategic locations in the compressor package. It has been determined through experimentation that, if the pressure at the inlet of the stage two compressor is less than the discharge pressure of the stage two compressor by more than an allowable value, then a high temperature condition will occur in the stage two compressor and cause the compressor to seize.

Abstract: A safety device for use in a fluid transfer and/or circulation system of the type which uses a pump to draw water from a reservoir through one or more intake lines each extending from an open end at the reservoir to the pump intake. The safety device connects to the fluid transfer/circulation system and includes a sensor, a triggering mechanism, and a vacuum breaker. When the pump is operating, the sensor monitors one or more conditions of the system. When one or more of the monitored conditions deviates outside of a normal operational range, as a result of an obstruction of any one or more of the open ends of the intake lines, the triggering mechanism triggers the vacuum breaker to eliminate negative pressure in the system by introducing air from atmosphere into the intake lines, thereby removing suction at the open ends of the intake lines. The safety device may further activate warning devices including audible and visible alarms to indicate that the system has been deactivated.

Abstract: In a capacity control method for an oil-free screw compressor, when an air consumption is larger than a set amount, a rotation frequency of a motor using an inverter to drive the compressor is set to be variable. When the air consumption is a set air amount or less, the inverter is controlled in such a manner that the rotation frequency of the motor is kept at a constant value. In this state, when an operation gas pressure of the compressor reaches an upper-limit value, an air release valve is opened to discharge the operation gas to the atmosphere. Additionally, the rotation frequency of the motor is lowered to a lower-limit value. Re-compression in the compressor can be prevented, and a compressor drive torque is lowered.

Abstract: An electronic control system dynamically varies the output capacity of a compressor by controlling plural valves associated with the compressor to provide pressurized air to a distribution system at an appropriate rate. The control system operates in any of three modes for standalone operation, including continuous run, auto/dual pressure band, and target pressure modes. In the first two modes, pressure bands are dynamically calculated based on load and unload values entered by an operator. These electronic control systems can also be connected in a peer-to-peer network to coordinate control of up to 16 compressors feeding the same distribution system, so as to maintain a desired target pressure in the system. A modem connected to the system supports remote diagnostics, monitoring, and control. Specialized startup, operating, and shutdown diagnostic algorithms prevent damage to the compressor and avert unsafe operating conditions.

Abstract: A mini-environment control device includes an individual enclosure to contain a sample and to isolate it from the external environment. An array of micropumps attached to the individual enclosure generates and maintains a controlled vacuum in the individual enclosure. Transfer means introduce the sample into the individual enclosure and extract it therefrom. The micropumps of the array of micropumps can be of a type employing the thermal transpiration effect. Temperature and pressure microsensors and a gas analyzer enable the operation of the array of micropumps to be controlled by an onboard microcomputer. The atmosphere surrounding a sample is therefore controlled.

Abstract: A pump control system and method employs a variable drive for controlling the speed of an AC electric motor driving a cyclic load. A real-time tuning of the frequency and voltage of the AC input to the motor allows a controlled variation of a cycle speed of the cyclic load. The control system and method adjusts motor speed according to a desired motor speed characteristic for different portions of a complete cycle and over multiple cycles of the cyclic load. The variable drive rectifies a poly-phase AC power input to provide a source of DC power on a DC bus and periodically samples the DC bus current and DC bus voltage across the DC bus to optimize the motor operation.

Abstract: A dynamometer readout (42, 46) and method is disclosed for obtaining dynamometer information (110) related to pumpjacks (10). For this purpose, a change of pivotal direction of the walking beam (18) may be detected by processor (82) utilizing an encoder component (60) with spaced slots (64) therein and light signal devices (68, 70, 72, 74) positioned to have a spacing different from that of the spacing of the slots (64). Software techniques filter out effects of stray mechanical vibrations. An infrared transceiver (46, 50, 100) of a preferred embodiment includes a radio frequency carrier generator (90) and modulator (88) that produces an infrared signal receivable by a low cost consumer radio receiver. The radio frequency modulation technique for infrared signals (96) and related filtering (98, 102, 104) condition formatted infrared signals for utilization in daylight and through a car window for drive-by downloading of data to second computer (108). A sensor (163) may be substituted for the encoder.

Abstract: An inventive scroll compressor has its motor protector circuit mounted on the compressor pump unit. In this way, increased temperature from reverse rotation of the orbiting scroll causes the motor protector unit to quickly stop operation of the motor. Preferably, the motor protector unit is mounted on the non-orbiting scroll.

Abstract: An apparatus and method of controlling air compressors is disclosed. In this invention, an air compressor is started to supply compressed air to an air tank. A temperature sensor senses the lubrication oil temperature of the compressor, and outputs a temperature signal to the controller, which compares the sensed oil temperature with a preset reference temperature. When the sensed oil temperature is not higher than the preset reference temperature, a pressure sensor senses the compressed air pressure within the tank, and outputs a pressure signal to the controller. When the compressed air pressure is higher than a minimum pressure, the controller lowers the frequency of a drive signal for the air compressor and operates the air compressor at a low rpm. When the compressed air pressure is higher than a preset maximum pressure, the controller operates the air compressor at a minimum rpm and partially discharges compressed air from the tank into the atmosphere.

Abstract: A liquid pump and controller with separate pump activation and deactivation mechanisms that are both closed detector devices is provided. The pump activation mechanism includes a float device that activates a pump motor when water within a housing of the pump reaches a high water level. The pump deactivation mechanism includes a sensor that detects the load on the pump motor and deactivates it when the sensed load indicates that the water within the pump housing has reached a low water level.

Abstract: A multi-stage blowdown valve is provided that uses a single control signal to simultaneously decompress the interstage and the second stage in a compressor system. The valve uses a series of sliding spools located linearly within a single bore to either prevent or allow fluid communication between two isolated passageways each having an inlet port and a discharge port. The valve, when used as a two stage blowdown valve in a multi-stage compressor system, can prevent compressor failure from occurring by ensuring that both the interstage and the second stages are decompressed, not only the interstage.

Abstract: A multi-stage blowdown valve is provided that uses a single control signal to simultaneously decompress the interstage and the second stage in a compressor system. The valve uses a series of sliding spools located linearly within a single bore to either prevent or allow fluid communication between two isolated passageways each having an inlet port and a discharge port. The valve, when used as a two stage blowdown valve in a multi-stage compressor system, can prevent compressor failure from occurring by ensuring that both the interstage and the second stages are decompressed. not only the interstage.

Abstract: A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Abstract: A controller for controlling operating parameters associated with fluid flow, speed or pressure for a centrifugal pump for pumping fluid, wherein at least one sensor is coupled to the pump for generating a signal indicative of a sensed operating condition. The controller comprises a storage device for storing data indicative of at least one operating condition and a processor in communication with the sensor and operative to perform an algorithm utilizing the at least one sensor signal and the stored data indicative of the at least one operating condition to generate a control signal, wherein the control signal is indicative of a correction factor to be applied to the pump.

Abstract: A multi-stage blowdown valve is provided that uses a single control signal to simultaneously decompress the interstage and the second stage in a compressor system. The valve uses a series of sliding spools located linearly within a single bore to either prevent or allow fluid communication between two isolated passageways each having an inlet port and a discharge port. The valve, when used as a two stage blowdown valve in a multi-stage compressor system, can prevent compressor failure from occurring by ensuring that both the interstage and the second stages are decompressed, not only the interstage.

Abstract: Systems and related methods pump fluid through a pump having a stroke volume. The systems and methods employ gravimetric control measures to monitor fluid flow through the pump. An actuator interacts with the pump during a stroke interval (TStroke) to pump fluid through the pump. The systems and methods couple a receptacle to the pump, to either dispense fluid into the pump or to receive fluid from the pump. The systems and methods detect changes in weight of the receptacle over a sample time period. The systems and methods achieve a desired flow rate (QDesired) by deriving an actual flow rate (QActual) by sensing changes in weight of the receptacle over the sample time period, taking into account the density of the fluid, and adjusting the stroke interval based upon QActual so that QDesired is achieved.

Abstract: A dynamometer readout (42, 46) and method is disclosed for obtaining dynamometer information (110) related to pumpjacks (10). For this purpose, a change of pivotal direction of the walking beam (18) may be detected by processor (82) utilizing an encoder component (60) with spaced slots (64) therein and light signal devices (68, 70, 72, 74) positioned to have a spacing different from that of the spacing of the slots (64). Software techniques filter out effects of stray mechanical vibrations. An infrared transceiver (46, 50, 100) of a preferred embodiment includes a radio frequency carrier generator (90) and modulator (88) that produces an infrared signal receivable by a low cost consumer radio receiver. The radio frequency modulation technique for infrared signals (96) and related filtering (98, 102, 104) condition formatted infrared signals for utilization in daylight and through a car window for drive-by downloading of data to second computer (108). A sensor (163) may be substituted for the encoder.

Abstract: A forecourt fuel pump has a casing locating means for metering and delivering to a flexible hose liquid fuel to be dispensed, and a processing unit arranged to monitor and control the delivery of fuel and the display of information concerning that delivery. The pump is provided with at least one sensor for an environmental parameter associated with the pump, such as the sensing of hydrocarbon liquids in the casing. Further sensors external of the pump may be provided to sense other parameters such as the presence of hydrocarbon vapor or liquids. Each sensor provides an output which is supplied to the processing unit which is arranged to monitor the output and provide an indication if the sensed value falls outside a pre-set range.

Abstract: A multi-stage blowdown valve is provided that uses a single control signal to simultaneously decompress the interstage and the second stage in a compressor system. The valve uses a series of sliding spools located linearly within a single bore to either prevent or allow fluid communication between two isolated passageways each having an inlet port and a discharge port. The valve, when used as a two stage blowdown valve in a multi-stage compressor system, can prevent compressor failure from occurring by ensuring that both the interstage and the second stages are decompressed, not only the interstage.