Abstract: A method for removing insoluble materials from a liquid mixture, including spinning at least one centrifuge separator at a predetermined speed and pumping the mixture to the spinning centrifuge separator at a predetermined rate. The rate in which the mixture is pumped to the separator is varied in response to a variable angular moment of force in the centrifuge separator caused by density variations in the mixture. The method is carried out by an apparatus including at least one centrifuge separator coupled in fluid communication to at least one pump. A closed-loop feedback system is operably coupled to the devices driving both the separator and the pump to control the rate in which the mixture is supplied to the separator. The rate is determined by the angular moment of force in the separator which then allows the system to increase, maintain, or decrease the output of the pump.

Abstract: A water pressure control system in which the pressurizing pump is turned on only in response to low pressure but is turned off only in response to low water flow rates. Water flow is detected with a magnetic switch displaced by water movement. After the pump is turned on, it can not be turned off for ten seconds, to smooth operation. When the system is first activated, the pump is turned on for sixty seconds, without regard to the other control functions, to guarantee priming of the pump.

Abstract: A non-invasive technique and system is provided for measuring flow of liquid driven by a flexible diaphragm of a membrane pump (18). Flow, pressure and/or temperature of a gas, such as air, used to drive the pump (18) is continuously monitored. Instantaneous volume of liquid being pulled into or out of a chamber of the pump (18) can be calculated from measured values of the gas used to drive the pump (18). Sensors (10, 12 and/or 14) are used to measure values relating to the gas. The sensed parameters are concurrently monitored and continuously determine the amount of gas flowing to and from the diaphragm of the membrane pump (18) utilized to move liquid within a liquid pathway. The measurements may then be used to calculate the instantaneous flow rate of the liquid.

Abstract: A liquid coolant circulation control system that minimizes the requisite feed pressure and keeps the flow rate of a liquid coolant constant includes a casing accommodating electronic circuits to be immersed in and cooled by a liquid coolant, a feed pump for feeding the liquid coolant to the casing, and a collecting pump for collecting the liquid coolant from the casing. A first measuring meter, interposed between the feed pump and the casing, measures a flow rate and/or a pressure of the liquid coolant flowing into the casing. A second measuring meter, interposed between the casing and the collecting pump, measures a flow rate and/or a pressure of the liquid coolant flowing out of the casing. A determining section calculates a difference or differences between the two flow rates and/or pressures. The determining section sends this information to a control section. The control section controls the output of one or both pumps, so that the difference or differences remain at a predetermined value.

Abstract: A controller for controlling the capacity of a centrifugal chiller compressor. The compressor is driven by an electric motor and has variable inlet guide vanes that control the flow of refrigerant to the compressor. The controller establishes a dimensionless plot of possible points of compressor operation relating the pressure coefficient and the capacity coefficient of the compressor. The current operating point of the centrifugal compressor is located on the plot and a dynamic surge boundary control curve is positioned proximate a region of actual surge. Control is exercised responsive to the variations of the region of actual surge and the surge boundary control curve for controlling compressor capacity by varying the opening of the inlet guide vanes and varying the speed of the compressor to move the operating point of the compressor proximate the surge boundary control curve.

Abstract: The present invention provides a check valve which, when placed at the end of a pump suction pipe, allows the pump to draw fluid therethrough from a continuously replenished, below-ground fluid source. When the fluid in the fluid source has been depleted to a level below that which allows fluid to be drawn therefrom by the pump, the present check valve maintains the suction pipe full of fluid. The check valve also maintains the suction pipe full of fluid when the pump has been shut off. In this manner, the pump can resume drawing fluid from the fluid source without the need for priming.

Abstract: A pump controller coupling the electric motor of a cyclically operating well pump to a power line is arranged to measure instantaneous power consumption of the motor, to integrate the power consumption over pump cycles, and to assess the performance of the well and/or pump by using the total power consumption to estimate fluid flow. The controller determines a phase reference in the cycle of the pump by monitoring for a peak or zero crossing in the instantaneous power level, specifically the point at which the pump changes over from a power stroke to regenerative operation due to pump momentum. The integrated total power consumption is reduced by an offset factor representing frictional losses, and scaled to obtain an approximate fluid volume determination for the pump and well. The factors used for offset and scaling can be adjusted by calibration using at least intermittent measurements of actual fluid flow and fluid density.

Abstract: A pump control controls the rate at which liquid is pumped through a tube. The pump has a variable speed shaft with a roller thereon engaged with the tube between the tube inlet the tube outlet for pumping liquid from a supply toward the tube outlet when the pump shaft operates. A first sensor senses liquid at a first location in the tube and a second sensor senses liquid at a second location in the tube between the first location and the tube outlet. A vibratory beam is coupled with the tube between the first location and the second location. An electric circuit transfers energy to a magnet on the beam and induces a natural response in the beam and the tube.

Abstract: A portable sampling pump apparatus including a flow control mechanism having a laminar flow meter for providing a precise readout of the volumetric flow rate of the pump as well as feedback control for the pump motor. The pump apparatus includes an electric motor, a pump operably driven by the electric motor, a laminar flow element positioned in a flow path of the pump, a pressure transducer for sensing a pressure drop across the laminar flow element and for producing an electrical signal that is directly and linearly proportional to the volumetric flow rate through the pump, and a motor control circuit which uses the electrical signal to control the voltage applied to the motor and to thereby regulate the flow of the pump. This electrical signal is also used to generate a display for the user of the volumetric flow of the pump.

Abstract: A pump is driven by a pump motor drive circuit that produces a series of pulse width modulated signals. A closed loop system is included to provide data indicative of any variation in the fluid flow. This is accomplished by using a Venturi located in the fluid flow path to create a pressure differential indicative of the fluid flow. A pressure transducer electronically measures this pressure differential which is then compared to a reference pressure differential indicative of the desired fluid flow. Any variation between the measured and desired fluid flow causes the pump motor drive circuit to vary the width of the pulses that are transmitted to the pump motor.

Abstract: An apparatus for on/off controlling a pump in a water distribution network, which ensures a practically constant pressure through the distribution network, comprises, within a body, a chamber having an inlet conduit adapted for connection to the delivery side of the pump and an outlet conduit adapted for connection to the network, a pressure switch placed in said chamber to issue a start signal to the pump at a predetermined pressure setting, and a flow switch placed in the outlet conduit to issue a start signal to the pump upon the occurrence of a predetermined minimum flow or a stop signal to the pump in the event of the flow being interrupted.

Abstract: A pump control interface for use in a diaphragm pump including at least one diaphragm adapted to move between a suction stroke and a discharge stroke during operation of the pump. A diaphragm follower is connected for movement with the diaphragm during operation of the pump. A sensor mechanism is provided for sensing at least the position and rate of movement of the diaphragm by sensing the position and rate of movement of the diaphragm follower. In one embodiment, the control interface is provided as a rod interconnecting two diaphragms of a dual diaphragm pump for synchronous movement. A plurality of conductive targets are disposed on the rod, and a proximity switch is mounted adjacent to the rod, in order to produce pulsed output signals when in proximity with the conductive targets.

Abstract: A surgical laser smoke evacuation system includes a sensor positioned at the surgical site to determine the need for evacuation. A vacuum pump draws smoke from the site through a system of conduits, including an in line filter. The filter tends to become clogged over time. A sensor determines changes in the pressure drop across the filter, and is connected to a control mechanism which adjusts the speed of the vacuum pump to maintain an approximately constant flow across the filter.

Abstract: A control system (10) for a variable speed centrifugal pump (12) in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable in accordance with the invention includes a sensor (14) for sensing an operational parameter of an output flow pumped by the pump; a variable speed drive (16) for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller (22), responsive to the sensed operational parameter, for producing the commanded speed signal (N) as a function of pump speeds at which the pump pressure does not increase with increasing flow rate.

Abstract: Method and apparatus for optimizing the overall production efficiency of any pumping well based on accurate measurements of the time-averaged rate that fluid exists the wellhead. The improved apparatus includes temperature compensated, hermetically sealed electronic sensors that accurately measure the instantaneous rate of both pulsating and steady-state flow, and devices for processing measured flow-rate information to ascertain the performance of downhole equipment and fluid reservoirs. The apparatus is self-calibrating on any well, and automatically compensates for normal changes in both downhole equipment and reservoir performance that typically limit the operation of conventional well-control devices. The apparatus may be easily installed at ground level without major changes to existing wellhead equipment, and readily adapts to the efficient control of pumping equipment utilized with any other type of fluid reservoir.

Abstract: A water freeze prevention device is provided and includes a mechanism that is installed between a water meter and incoming water pipes to drain the water pipes to prevent the water pipes from freezing during severe cold weather conditions.

Abstract: A fluid flow control system maintains a constant, controllable, low flow rate through an orifice; intermittently operates a pump at an efficient, relatively high flow rate; and moderates flow between the pump and the orifice. The system is energy efficient and accurate.

Abstract: A well pump system having a motor-driven pump and a pressure tank for delivering water from a source to a utilization point. A sensing device detects a parameter correlated to the rate of flow into and out of the pressure tank. The parameter is utilized to regulate flow into the tank so as to establish at least approximate equality between flow into and out of the tank.

Abstract: A hydropneumatic arrangement is provided for actuating a pump upon pressure decrease and for deactivating the pump upon flow decrease. The hydropneumatic arrangement includes a bearing cylinder; a flow sensor piston movably disposed within the bearing cylinder; a driving piston connected to the flow piston by a common shaft, the flow sensor piston being moved according to a variation in consumption demand by an interaction of a force of flow exerted against the flow sensor piston and a force of pressure exerted on the driving piston. A pressure switch is provided and is electrically connected to an electric motor that drives the pump.

Abstract: A sewage pumping system includes a container, an inlet for the inflow of liquid and a modality for ascertaining the liquid level in the container. Two or more pumps are provided, each having an inlet communicating with a container and an outlet communicating with the common conduit. A pump controller receives information from the modality for ascertaining the liquid level and is adapted to start and stop individual pumps. A pressure sensing device is located in the conduit for sensing the backpressure against which pumps in operation are pumping, and for generating a second signal corresponding to the sensed backpressure, the signal going to the pump controller. An addressable memory is operatively connected with the pump controller and stores values corresponding to pumping rates vs. backpressure for each of the pumps, along with high and low backpressure values for each pump. On high backpressure the pump controller avoids pumpstarts which will not result in a net increase in the total pumping rate.

Abstract: A method for determining if fluid is being displaced by a volumetric pump. The volumetric pump (30) includes an inlet cracking valve (46) and an outlet cracking valve (52) disposed on opposite sides of a plunger (48) used to displace fluid by compressing flexible tubing (34). During a pumping segment of a pumping cycle for the volumetric pump, the outlet cracking valve is closed with a cracking force that compresses the flexible tubing until the pressure of the fluid displaced by the plunger exceeds a cracking pressure, at which time the outlet cracking valve opens to enable fluid flow from the volumetric pump. A cracking flexure (182) provides the cracking force. As the outlet cracking valve opens in response to the fluid pressure exceeding the cracking pressure, a flow detector (54) mounted to the cracking flexure responds to the stress generated in the cracking flexure thereby, producing a signal indicative of fluid flow from the volumetric pump.

Abstract: In a high-pressure cleaning appliance comprising a high-pressure pump driven by an internal combustion engine, a bypass line leading from the pressure line of the pump to the intake side of the pump and opening when the pressure line is closed, and a pressure sensor in the pressure line, in order to adapt the power of the internal combustion engine to the prevailing operating conditions, it is proposed that the pressure sensor reduce the speed of the internal combustion engine immediately the pressure in the pressure line drops below a certain value.

Abstract: An oval gear pump for shear-sensitive fluids particularly suited for use in dispensing metered amounts of food syrups, condiments, or other thick or viscous liquids. The viscosity of some of such materials tends to degrade when excessive agitation is incurred. The gear pump minimizes such agitation by sweeping integrated masses of substantial volume between the inlet and the outlet. The pumping system also provides a flow-sensing device including a tubular magnet movable against spring pressure by fluid flow to an operated position. When the magnet is in the operated position, an adjacent external switch is operated to produce a signal indicating flow. The pumping system is particularly adapted for use in connection with ice cream dispensing machines.

Abstract: In a rotary pump with a pressure switch, a pressure switch mounting space constituted by a small- and large-diameter holes is formed to be parallel to a rotating shaft in an end face portion of a front body to which a rear body is not joined. A pump outlet side fluid pressure is introduced to an inner end of the small-diameter hole. The large-diameter hole is connected to a pump inlet side. A plunger is slidably arranged in the small-diameter hole. The plunger is normally biased toward the inner end of the small-diameter hole and is kept movable toward the large-diameter hole depending on a magnitude of the fluid pressure of the pump outlet side. A pressure detector is operated when the fluid pressure of the pump outlet side exceeds a predetermined value.

Abstract: A protector device connected in series with a pool pump motor. When the automated pool timer contacts close, supplying AC power to pool pump motor, the protector apparatus logic permits instantaneous motor turn on and logic reset of apparatus clock timer. After a nominal period of time, pump motor will be shut off, unless water is flowing through pump motor. In the event water is flowing through pump motor, a water flow sensing switch in the water line to pump will override clock logic, and hold pump motor on, until the automated pool timer reaches a preset trip turn off time.

Abstract: The present invention relates to a method of qualitative and quantified monitoring of the instant local physical state of a substantially incompressible fluid material such as a liquid or pasty substance (for instance slurry or pulp) and a device for carrying out this method and the various applications and uses resulting from the working of the method and/or device for the automatic control of said physical state. The invention is also directed to the various equipment and systems provided with at least one such device.

Abstract: In a liquid well pumping system which is provided with a downtime between pumpoff cycles, the method of determining the maximum downtime includes running a plurality of tests to determine the relationship between runtime and downtime and determining when the relationship becomes non-linear for at least two consecutive tests. The downtime is selected adjacent the last linear relationship between runtime and downtime for providing a downtime which allows adequate fluid buildup in the well, but not so long a period as to loose well production.

Abstract: An exhaust fan blower is provided for use in induced draft furnaces. An integrally molded fan housing and exhaust conduit is provided of a material impervious to the corrosive effects of exhaust gas condensates. The conduit is of a round cross section to mate with an associated flue pipe. The fan blower includes a conduit in communication with a pilot light for constantly venting the pilot light irrespective of operation of the blower. A first bore in the fan blower housing provides means for monitoring the vacuum developed therein, while another bore provides a means for thermally sensing a blocked or restricted flue condition. A flange and mounting lugs about the periphery of the fan blower housing provide a means for mounting the system to the side of a furnace panel, while sealing such mounting engagement. A motor mounting bracket for the fan blower serves as a cooling fan guard and heat sink, having a bearing contact mounting seat cast integrally to the bracket.

Abstract: Method and apparatus for optimizing the overall production efficiency of any pumping well based on accurate measurements of the time-averaged rate that fluid exists the wellhead. The improved apparatus includes temperature compensated, hermetically sealed electronic sensors that accurately measure the instantaneous rate of both pulsating and steady-state flow, and device for processing measured flow-rate information to ascertain the performance of downhole equipment and fluid reservoirs. The apparatus is self-calibrating on any well, and automatically compensates for normal changes in both downhole equipment and reservoir performance that typically limit the operation of conventional well-control devices. The apparatus may be easily installed at ground level without major changes to existing wellhead equipment, and readily adapts to the efficient control of pumping equipment utilized with any other type of fluid reservoir.

Abstract: The problem of providing a simple, small, lightweight and reliable flow responsive switch mechanism (32) in a fan structure, such as for aerospace applications, is solved by providing a housing (12) defining a fan involute (22). An impeller (18, 20) is mounted in the housing for forcing air through the fan involute. A vane (34) is disposed directly in the fan involute, rotatably mounted on the housing, for rotation in response to air flow through the fan involute. An electrical switch (52) is mounted on the housing and is operatively associated with the vane for altering the state of the switch in response to air flow through the fan involute from the impeller.

Abstract: An automatic pump protection system is comprised of a plurality of sensors for measuring process parameters indicative of a loss of pump suction or of pump motor failure. Analysis of the parameters is performed by a microprocessor in order to determine whether conditions leading to a loss of pump suction or pump motor failure are present. The microprocessor then automatically initiates pump protective action in response to the foregoing analysis by tripping the pump or by providing an alternate suction source.

Abstract: A peristaltic pump controller provides control of a positive displacement pump as either an uncalibrated or calibrated flowmeter, or a calibrated dispenser. A calibration constant is calculated, after the pump is primed, to determine the amount of volume output produced by an increment of angular rotation of the pump. The constant is determined during a calibration operation where an arbitrary calibration volume is metered. The controller has a low flow and high flow mode where the low flow mode provides a higher resolution for dispensing. The flow mode of operation is determined by the value of the calibration constant and is automatically set when the constant is calculated. DUring a dispensing operation, the controller will meter fluid to within a predetermined amount of the final volume dependent upon the speed of the pump motor and then dribble in the remaining amount of a batch for precision.

Abstract: A vortex amplifier functions as a choke valve to control flow in a flow line from, for example, a gas or oil well. The vortex amplifier is arranged in the flow line such that flow passes radially through the vortex amplifier to emerge at an axial port. A control flow is introduced tangentially into the vortex amplifier along a line by a pump. The pump is regulated by a transducer responsive to signals generated by the flow in the flow line.

Abstract: A pumping apparatus for delivering liquid at a high pressure, in particular for use in liquid chromatography, comprises two pistons (10, 20) which reciprocate in pump chambers (7,18), respectively. The output of the first pump chamber (7) is connected via a valve (13) to the input of the second pump chamber (18). The pistons are driven by linear drives (30,31), e.g., ball-screw spindles. The stroke volume displaced by the piston (10) is freely adjustable by corresponding control of the angle by which the shaft of the drive motor (36) is rotated during a stroke cycle. The control circuitry is operative to reduce the stroke volume when the flow rate which can be selected by user at the user interface (42) is reduced, thus leading to reduced pulsations in the outflow of the pumping apparatus. The pumping apparatus can also be used for generating solvent gradients when a mixing valve (2) connected to different solvent containers (A,B,C,D) is coupled to the input of the pumping apparatus (FIG. 1).

Abstract: An oil well pump control for regulating operation of a pumping apparatus such as a pumping jack through a timing system which is actuated by the fluid pulses or surges that result from the pumping action of the pump.

Abstract: Liquid is removed from a remote location, with control of the system responsive to the supply of the liquid to be removed. Control is accomplished without the need for electrical devices at the remote location by means of a valve in the remote location in the conduit circulating a powering fluid to a pump at the remote location, and the sensing of the accompanying changes in flow or pressure in the powering fluid conduit or output conduit.

Abstract: A lubricating delivery system includes a positive displacement lubricant pump and fluid flow measuring means for monitoring the output of the pump. The pump is a miniature injection pump and the measuring means includes switch means responsive to movement of the check valve provided at the output of such a pump. Because such a system provides flow measurement by a single digital input to a programmable controller, numerous pumps may be utilized to individually supply lubricant to separate portions of a machine and all may be monitored for output flow without tying up an inordinate portion of the PC input circuitry, which is typically required to additionally control the machine being lubricated.

Abstract: A pump-off control for a pumpjack unit. The pumpjack unit has a flow line therefrom connected to a tank battery. A control device is connected in the flow line so that all of the production must flow therethrough. The control apparatus includes an orifice placed in the flow line and a bypass arranged for flow to occur around the orifice. A movable member is placed within the bypass and each stroke of the pumpjack moves the member in proportion to the quantity of liquid flowing therethrough. The movable member is connected to actuate a switch device, indicator, chart, and counter. The orifice is sized respective to the movable member so that each stroke of the pumpjace causes the movable member to move in proportion to the produced fluid forced through the bypass. The switch device is positioned to be actuated at a predetermined flow rate each stroke of the pump.

Abstract: An apparatus and method controls a dual piston pump for a liquid chromatography system so as to pump a flow of solvent through the liquid chromatography column at a constant flow rate and with a solvent composition which is substantially equal to the desired solvent composition despite changing conditions of compressibility of the solvent. A computer is used which measures the time it takes the pump shaft to move through an overlap region in the pump cycle when both pistons are simultaneously pumping as normalized to the time taken by the pump to move through a constant velocity portion of the piston travel defined by the user. This time is compared to the time stored in the computer for the particular flow rate used to measure the time defined above for the pump to move through the overlap region for an incompressible solvent at low pressure as normalized to the time taken by the input piston to move through the same user defined segment of the constant velocity portion of the travel of the input piston.

Abstract: Pumping system with a desilting arrangement having a bidirectional water pump disposed in a housing which has a pump inlet and a pump outlet. The system also has a silt blow-out pipe with a desilting valve therein, connected at one end to the pump outlet and having the other end spaced a certain distance away from the pump inlet and below the water level. Desilting is performed by opening the desilting valve and operating the pump in reverse direction for blowing silt, accumulated at the pump outlet, away.

Abstract: A pump control apparatus including a variable speed pump controllable in response to a pump drive signal, a signal generator generating a commanded flowrate signal indicating desired flowrate of the pump, a flowrate sensor providing a sensed flowrate signal indicating sensed flowrate of the pump, and an integrator connected to the sensor and generator to receive and integrate the commanded flowrate signal and the sensed flowrate signal and to provide the pump drive signal based on the difference in integrated values of the signals so as to achieve desired commanded volume over time.

Abstract: A low-flow pump-off control device for deactivating a motor for a pump during conditions when a rate of supply of a source of fluid to be pumped by the pump is insufficient includes: a pipe section having an inlet and an outlet, the inlet being connectable to the source of fluid to be pumped through the pipe section; a plurality of plates disposed substantially perpendicularly in the pipe section, each of the plates defining at least one orifice through which the fluid is caused to pass; a differential pressure switch for sensing a differential pressure between a pressure upstream of a first one of the plates and a pressure downstream of a last one of the plates that is at or below a set point indicative of a predetermined low flow rate of the liquid; a first timer in communication with the switch for accumulating periods of time at which the switch senses the differential pressure; a motor activation and deactivation relay in communication with the timer for deactivating the motor when the accumulated period

Abstract: To stabilize flow rate in a single-stroke, syringe-type high pressure pump at a constant value after turn-on, a control system increases the pump speed until equilibrium conditions are reached and then pumps at the present rate. In one embodiment, the system is operated in a constant pressure mode under the control of a feedback system to a point at which the pressure is estimated to provide the desired flow rate, with feedback being provided from a pressure measurement and from a flow rate measurement. The feedback from the flow measurement is increased logarithmically with the rate of pumping prior to being compared with the pressure error signal and the comparison between the previous error signal and the logarithmic flow rate signal is used to control the speed of pumping.

Abstract: This invention relates generally to the sensing of phenomena using heat sensitive devices. More particularly, the invention relates to an improved method and system wherein the ratio of the dissipation coefficients of a pair of electrically heated matched temperature sensitive devices is detected, which method and system are insensitive to variation in ambient temperature.

Abstract: A detector for determining when an occlusion has occurred in the fluid line of an IV administration set comprises means associated with an IV infusion pump to determine the resistive force exerted by fluid in the line against the pumping mechanism of the pump. The detector includes a flexible beam which is mounted between the plunger and the activator of the pumping mechanism and which bends proportionately to the magnitude of the resistive force. A strain gauge attached to the beam activates an alarm which stops the IV pump when flexure of the beam indicates an occlusion in the line has occurred.

Abstract: In a high-pressure cleaner, in order to control additional equipment, such as chemical doser or burner, from a hand spray gun without any special control lines, it is proposed to connect a second closable flow path in parallel with the normal flow path through the spray nozzle, to determine the pressure rise time in the cleaning fluid after the switching on of the high-pressure pump and to generate a control signal by opening the second flow path to extend said rise time compared with the rise time when the second flow path is closed; furthermore, a high-pressure cleaner is proposed for implementing this process.

Abstract: An arrangement for controlling the pressure of a fluid being pumped by a pump driven by a drive means. The pump pressure is measured by a pressure sensor and transformed into an electrical signal which acts on a regulator for the drive means.

Abstract: A control device for a power-driven pump used for a car comprising a d.c. motor, an air pump driven by the d.c. motor and an exhaust device for reburning and purifying exhaust gas from an engine by actuating the air pump, wherein sensors for detecting quantity of air necessary to be fed into the exhaust device to purify the exhaust gas and a variable control device to variably control the revolution speed of the d.c. motor depending on the quantity of air.

Abstract: Fluid flowmeter, air conditioning system and method of controlling the air conditioning system which includes a Karman vortex generator, ultrasonic transmitter and receiver apparatus and networks for detecting the Karman vortices and for detecting and controlling information of a received wave and a reference wave of the ultrasonic transmitter. The flowmeter detects an air flow volume and/or speed by Karman vortex detecting means using ultrasonic waves. The air conditioning system utilizes the fluid flowmeter for measuring air flow volume and/or flow speed in a duct between an air conditioning apparatus and a chamber to control air flow volume in response to information from the flowmeter.

Abstract: In accordance with the present invention, the actual volume of a liquid chemical additive used to treat fuel is measured by an additive flow transducer so that a desired mix ratio can be maintained. In a first preferred embodiment, the amount of additive measured is converted to an equivalent volume treated fuel, and displayed. The user watches the display and stops adding additive when the display indicates that he has already added sufficient additive to treat the actual amount of fuel to be added to the fuel tank. In a second preferred embodiment, the user sets in the desired mix ratio and the volume of fuel that is to be added to the tank, and an electrically driven pump adds additive to the tank until a desired mix ratio obtains. In a third preferred embodiment, both the cumulative fuel flow and cumulative additive flow are sensed and the rate of additive flow is controlled by an automatic control system seeks to maintain a desired mix ratio.