Abstract: A precision controlled variable speed pumping system for controlling the operation of one or more independently driven pump motors includes one or more valveless rotary pumps each having a reciprocating piston directly driven by an individual stepping motor and a digital control circuit for individually directing the operation of each stepping motor whereby the resultant sum output of the pumps may be utilized for mixing, blending or proportioning fluid flow.

Abstract: A plastic extrusion apparatus is provided which includes a gear pump for accurately metering the plastic through a die. The apparatus is adapted to process highly viscous plastic material under high temperature and pressure conditions, and the gear pump includes a non-leaking and substantially frictionless seal for the drive shaft. The seal comprises a sleeve surrounding the shaft, and a shallow helical channel formed in the bore of the sleeve, with the helical channel being of a hand such that forward rotation of the shaft results in the plastic which enters the clearance between the shaft and sleeve to be effectively pumped back toward the interior of the housing.

Abstract: A hand held electric ejecting device is disclosed for ejecting material such as caulking from a cartridge. The ejecting device comprises in combination, a receptacle for receiving therein a cartridge containing a material to be ejected, the cartridge having a dispensing opening at one end and being adapted to receive a pusher at the other end for forcing the material in the cartridge through the dispensing opening; a pusher movable when driven through the cartridge from the other end to force the material in the cartridge through the dispensing opening, the pusher including a push rod; and an electric motor positioned adjacent one end of the receptacle and connected to the device, the push rod passing through the electric motor and being axially driven thereby for effecting movement of the pusher to force material through the dispensing opening of the cartridge.

Abstract: A control unit for controlling a vibratory bowl feeder which is effective to maintain, for varying feeder loads, a constant preselected amplitude of bowl feeder vibration at a vibratory frequency which coincides with the changing mechanical resonant frequency of the feeder system. The control unit includes a sensor which detects the amplitude and frequency of feeder bowl vibration, a frequency control loop and an amplitude control loop. The frequency control loop is responsive to the detected frequency of vibration and provides an oscillating signal which coincides with the resonant frequency of the system. The amplitude control loop is responsive to the detected amplitude of vibration and includes a variable gain amplifier which amplifies the oscillating signal to provide a feeder driving signal which causes the feeder to vibrate at the system resonant frequency at a preselected amplitude.

Abstract: A fluid dispenser pumps fluid in increments. The dispenser includes a computer which, on command, determines the volume of fluid dispensed per increment, the determined value constituting a calibration value which is stored in the memory of the computer. A controller which may include the computer as a component provides for dispensing a selected number of doses, each of a selected volume. The controller can also specify a time interval between the delivery of successive doses. The dispenser is particularly useful in combination with apparatus for charging petri dishes with agar.

Abstract: A system for injecting chemicals into a fire fighting system of the type using a plurality of water hoses and having a source of water and a source of chemicals. A servo motor system is connected to automatically meter a certain ratio of chemicals into the water supply. The servo motor system is responsive to the total flow to control the chemical pump to pump a certain ratio of chemicals into the water supply even if the total flow varies. Various modifications are disclosed.

Abstract: A programmable electronic speed control for controlling the speed of a motor responsive to an ac signal source. A triac switch is interposed between the ac signal source and the motor. A programmable digital counter is connected between the ac signal source and the triac switch. The programmable counter counts zero voltage crossings of the ac signal generated by the ac signal source and repetitively causes the triac switch to alternately pass and block selectable numbers of cycles of the ac signal to the motor. The speed of the motor is determined by the relationship between the selectable numbers of cycles of the ac signal which are alternately passed and blocked by the triac switch. The speed control is particularly suited for use in controlling the pump motor and/or the program timer motor in a beverage dispensing machine.

Abstract: In a wet cycle copier of the small tabletop mounted variety, conversion is made for vending in the absence of frequent key operator attention. Incidence of power interruption provides for a soak cycle to occur wherein the liquid toner is cycled through the machine without drum rotation. Rotation of a glass selenium coated drum against a dried and abrading liquid applicator is avoided. After the soak cycle and assuming uninterrupted power, a cleaning cycle is initiated once every 24 hours. Assuming a lack of machine use, this cleaning cycle lubricates both toner application roller and drum to assure a wet toner applicator. Dispersant replenishment is supplied from a large volume reservoir under logic control with provision made for automated machine shutdown where dispersant on demand is not supplied. Provided modes of operation include coin vending, countermechanism vending and direct owner access vending with a tamper proof interface between the provided modes.

Abstract: A counter counts the time intervals of falling instilled drops in response to a signal issued each time a falling instilled drop is detected. A memory is supplied with data representing the quantities of a falling instilled drop corresponding to the time intervals at which the drops fall. The data corresponding to the time intervals thereof which have been counted by the counter are read out of the memory. The data thus read out are accumulated to determine the total quantities of the drops.

Abstract: A two-component molding system according to this invention has a pair of supplies each containing a quantity of a respective fluid synthetic-resin component capable of reacting and hardening with the other component. Respective conduits having upstream ends connected via pumps to the respective supplies and downstream ends connected via metering devices to a mixing chamber extend from these supplies. Molds are connected to the mixing chamber. A controller connected to the pumps and to the metering devices determines the pumping volume/time rates and compares them with the respective downstream actual volume/time rate at the downstream ends of the conduits. In the event that the actual rates are not substantially identical to the pumping rates, the controller sounds an alarm and shuts down the system.

Abstract: The instant invention relates to an apparatus for metering at least two flowable reaction components, such as polyurethane-forming components, in a predetermined ratio into a mixing chamber. The apparatus broadly comprises a metering unit for each component, which is made up of a piston and cylinder, a feed pipe leading from a storage container into the cylinder, a delivery pipe leading from the cylinder to the mixing chamber and optionally a return pipe, and a drive unit. Each drive unit is in the form of an electro-hydraulic linear amplifier which comprises a stepping motor for a control mechanism which is coupled to a hydraulic piston and cylinder, wherein the drive unit is capable of driving the metering piston. Control electronics are provided for controlling the metering units. The controls comprise at least one adjustable control frequency generator for generating signals to be fed to the electro-hydraulic linear amplifiers to control the movements of the metering pistons.

Abstract: A mechanical drive system for providing a maximum limit on the magnitude of unidirectional output motion in response to reciprocating input motion, including: an output member moveable in a first direction; a unidirectional drive for driving said output member in said first direction; limiter chain for limiting the motion of the unidirectional drive in the first direction to define a limit position; and an override drive mechanism responsive to the reciprocating input motion occurring in one direction to move the unidirectional drive to a rest position and to the reciprocating input motion occurring in the opposite direction to move the unidirectional drive in the first direction from the rest position no further than the limit position, irrespective of the extent of the reciprocating input motion to the override drive mechanism; and a periodically actuated fluid dispenser unit utilizing such a drive mechanism.

Abstract: A system for injecting chemicals into a fire fighting system of the type using a plurality of water hoses and having a source of water and a source of chemicals. A servo motor system is connected to automatically meter a certain ratio of chemicals into the water supply. The servo motor system is responsive to the total flow to control the chemical pump to pump a certain ratio of chemicals into the water supply even if the total flow varies.

Abstract: An apparatus for dispensing material, especially tobacco, in portions of predetermined weight from a stream of irregular density. A variable speed feed system passes the material through a measuring region where its density is monitored and the feed speed is automatically adjusted to compensate for measured variation in the density to provide discharge of portions of predetermined weight from the feed system at regularly spaced time intervals. The relative separation positions of the portions may be calculated by determining the weight of each portion from both the density information and the feed speed, separation of the portions being effected when the separation position previously calculated reaches the end of the feed system.

Abstract: A control system for regulating the speed of a truck-mounted material conveyor includes a direct current drive motor and a truck-driven shunt generator for providing power to the motor. A control circuit has a reference input representing desired delivery rates in material weight per unit of distance and a truck speed input. A multiplier circuit converts the inputs to a delivery rate in terms of material weight per unit of time at the current truck road speed. Generator and conveyor speed feedback loops are provided to maintain a desired conveyor speed despite variations in truck engine speed or slippage at the conveyor.

Abstract: A machine is disclosed for repeatedly metering out quantities of a predetermined volume of fluid freshly mixed from a plurality of component sources. A mixing member (which may comprise simply a duct) is coupled to receive a plurality of component fluids through positive control valves. Reciprocating metering structures (cylinder-piston), connected to the valves, are driven in a controlled fashion by pressurized fluid and a reciprocating actuator. The control system incorporates sensors for detecting the positions of the metering structures as well as the valves to provide timely signals which change the valve positions and reverse the stroke. With the valves in one position, and upon movement of the actuator in one direction, fluid flows under pressure from a component source to an associated metering structure, then with the valves in another position, the actuator is reversed and the fluid is discharged from the metering structure to the mixing chamber.

Abstract: In an apparatus for the pulse-wise dispensing of very small amounts of liquid controlled with a measuring instrument. The measuring instrument comprises an ejector for the pulse-wise ejection of a desired amount of liquid and a measuring vessel having a volume greater than the volume of the liquid to be ejected for each pulse. The measuring vessel has an outlet connected to the ejector and a cross-section of the vessel is adapted to the amounts of liquid to be controlled. A sensing apparatus has an upper and lower sensing device positioned at the vessel and responsive to the level of the liquid therein with an accuracy of about from 1 to 5 amounts of liquid to be ejected and which generates a signal when the upper and lower sensing devices are activated.

Abstract: Apparatus for measuring out material from a cold feed bin for use with a drum mix plant. The apparatus comprises a plurality of cold feed bins supported on a plurality of legs above a frame. Each leg of the bins rests upon a load cell which thereby measure the weight of the bin and material contained therein. Control circuitry connected to the load cells regulates belt feeders disposed below each bin which adjust the rate at which material is dispensed from each bin in response to the weight measured by the load cells to maintain a desired rate of weight reduction. A belt conveyor disposed below the belt feeders transports the dispensed material to the input of a mixing plant.

Abstract: The storage level of ore, supplied by an overhead loader to a bin or pile in the form of large, dense, hard fragments, up to a foot or more in diameter, is measured and controlled by repetitively lowering a line carrying a weight, having a mass at least as great as the largest ore fragments, from above the stored mass to the surface of the stored mass and measuring the distance traveled by the weight. Feed of ore is automatically stopped when maximum allowable level of stored mass is detected. Measurement of ore level is accomplished by counting, during the lowering of the weight, the pulses generated by a pulse generator operated by the turning of a winch upon which the line is reeled. The contact of the lowered weight with the stored ore mass is detected by the slowing of the rate of pulse generation as the weight ceases falling under the influence of gravity and the winch therefore ceases turning.

Abstract: A system for infusing fluids into the human body includes a peristaltic-type metering apparatus which controls the flow of fluid through a disposable administration set. The metering apparatus includes a control system which allows the volume and rate of flow of the fluid to be infused to be accurately preset by the operator. The control system provides an alarm function in the event of malfunction of the pump or occlusion of the tubing of the administration set, and a minimum pumping rate for maintaining fluid flow through the system after the desired volume of fluid has been infused. Novel power supply circuitry within the control system renders the system immune to power line transients, and a novel bubble detector circuit provides for more reliable detection of air bubbles in the tubing.

Abstract: The invention provides a valve for dispensing material from a hopper. The valve comprises a body defining a passage way, a generally L-shaped valve member pivotally mounted to one side of the passageway such that the inner faces of the arms of the valve member can engage respective ones of a pair of spaced back to back valve seats disposed in the passageway so that in use with the downstream of the two arms closing the passageway by engaging the downstream valve seat a charge of material in the hopper can be received between the two arms and dispensed when the valve member is rotated to open the passageway by the downstream arm and subsequently close it by the upstream arm engaging the upstream valve seat, flow through the passageway being substantially obstructed by the upstream arm as the valve member is returend to close the passageway by the downstream arm.

Abstract: A trailer-type vehicle for transporting and dispensing solid materials over the ground includes a self-contained, hydraulic power and control system driven by one of the vehicle's ground engaging wheels which operates a first dispensing mechanism at a selectable speed proportional to the vehicle's rate of travel over the ground, but operates a second dispensing mechanism at a constant speed regardless of the vehicle's rate of travel. A single hydraulic motor driven by a selectively engageable drive train connected with one of the vehicle's wheels is novelly employed as a hydraulic pump for delivering a force transmitting fluid through a pair of control valves to a pair of hydraulic motors respectively powering the dispensing mechanisms. One of the control valves includes provision for selectively adjusting the flow rate to the associated hydraulic motor thereby allowing adjustment of the volume of material being dispensed per area of ground covered by the vehicle.

Abstract: The invention relates to assemblies for use with refrigerators and refrigerators utilizing such assemblies to enable dispensing of cold water or ice made from purified water. Refrigerators of this type are provided with a unit which dispenses the cold water or ice and which units usually include a water input, and may on some occasions, include a valve in the input line. This latter valve is designed to open and close when the unit requires makeup water. An assembly is used in conjunction with the refrigerator and which assembly generally comprises a support means in the form of a cabinet for retaining a flask of purified water in an inverted position and where the water from the flask is introduced into a holding chamber in the cabinet. The water is pumped from the holding chamber by means of a pump in the cabinet, to the unit in the refrigerator through the water input.

Abstract: Apparatus and method for make up of a hemodialysis solution and supply of same to an artificial kidney; the solution optionally contains bicarbonate in any desired amount. The apparatus comprises a recirculation loop which mixes a hemodialysis dialysate concentrate with deaerated water and may include another interconnected recirculation loop adopted to form an aqueous bicarbonate solution. Both recirculation loops mix the concentrates in the recirculation fluid in venturi means operated by continuously controlling the velocity of fluid flowing therethrough to create suction to inject the requisite quantity of concentrate to form the final desired composition in the product hemodialysis solution.

Abstract: A flow rate meter is provided for measuring the flow rate of particulate material being conveyed in a fluid stream along a tubular member. The apparatus includes a throat portion in the tubular member which has a length sufficient to accomplish a pressure drop adequate for accurate particulate material flow rate measurement in the conveying of particulate material in a fluid stream through the throat. The pressure drop is measured across the throat and the measured pressure drop is correlated with the particulate material flow rate. There can be provided converging and diverging tubular sections on opposite sides of the throat to form a venturi. One or more of the flow rate meters can be used in the control of a particulate material blending system. A fluid flow rate measuring means can be used in conjunction with the flow rate meter to provide a signal representative of the difference between the flow rate of particulate material and fluid and the flow rate of the fluid alone, i.e.

Abstract: An apparatus for the essentially uniform feed or conveying of a fluent or flowable medium by means of to-and-fro moving feed or conveying pistons, wherein there are provided at least two single-acting feed pistons. Each of the feed pistons is equipped with a forward drive and a return drive. The return velocity is greater than the forward velocity. The forward drive and return drive are driven with a phase shift such that the terminal or end portion of the feed stroke of the one feed pump overlaps the starting portion of the feed stroke of the other feed pump.

Abstract: A digital weigh feeder includes a conveyor belt for transporting material thereon. The conveyor belt has an average tare weight. A digital weight transmitter provides at least first and second outputs having first and second frequencies respectively. The ratio of the first and second frequencies is indicative of the weight of material on the belt. A weight processor digitally computes a scaled ratio of the first and second frequencies. An auto tare circuit digitally computes the average tare weight of the conveyor belt. The computed average tare weight is substracted from the computed scaled ratio of the first and second frequencies to obtain a reading of the actual weight of material on the belt.

Abstract: A dispenser for crushed and cubed ice has a housing arranged forming an article containing chamber from which ice can be dispensed on demand through a discharge opening provided in the housing. A plurality of parallel, coextending screw conveyors are disposed within the chamber and disposed adjacent a floor thereof selectively moving ice toward the discharge opening of the housing without excavating the ice beneath the conveyors, with a baffle being disposed extending from adjacent the discharge opening for preventing bridging of ice within the chamber of the dispenser by causing part of the ice moved by the conveyors toward the discharge opening to orbit about the chamber.

Abstract: A dispenser system is disclosed comprising a liquid dispenser pump, an electronic circuit for controlling the dispenser system, and a dispenser for dispensing a flowing liquid through a metering orifice. The dispenser system enables mixing and dispensing of a first and a second liquid in accordance with a given volumetric relationship between the first liquid and the second liquid. The system includes flow for controlling the flow of the first liquid and a pump for pumping a second liquid. The electronic circuit includes a generator for generating an electrical pumping signal to power the pump for pumping the second liquid in accordance with an electrical pumping signal. An activator is connected to the flow and the generator for activating simultaneous flow and pumping of the first and second liquids, respectively, upon a selected signal from the activator.

Abstract: A digital, open loop control system for a very low speed conveyor which deposits contaminants in a fluid used to test a hydraulic component. The digital control system senses the rate of fluid flow through the component and advances the conveyor in proportion to the fluid flow rate.

Abstract: A method and apparatus for taking-in a fibre layer in blow-room machines wherein the fibre layer is pressed by a number of pivotable pedal levers distributed across the width of the machine, and loaded by a pressing device, against a take-in roll. In the absence of fibre material between the take-in roll and the pedal levers, the pedal levers are temporarily lifted-off the take-in roll.

Abstract: Apparatus for moulding articles of synthetic plastics. Plasticized plastics material is fed by a screw within a cylinder, along the cylinder to a nozzle from whence the material is injected into the mould cavity. The feeding of the material into the mould cavity is however effected by rotation of the screw almost in its forwardmost position instead of by longitudinal movement of the screw from its rearwardmost to its forwardmost position. The longitudinal position of the screw is adjusted during filling of the mould cavity by biasing apparatus acting axially on the screw and controlled by means sensing the position of the screw.The temperature distribution throughout the cylinder, the nozzle, the screw and the screw tip is controlled by separate cooling circuits for the various zones, the various cooling circuits coming into operation at various times during a moulding cycle, as determined by timing apparatus.

Abstract: This invention provides a container delivery system for vending apparatus for vending containers. The delivery system comprises a container store and dispenser, an arm moveable in to and out of the path of travel of a cup dispensed by the container dispenser for receiving the dispensed container to support it temporarily at an angle to its path of travel and an ingredient dispenser mounted to one side of the container dispenser for dispensing a charge of material into the angled container and a guide to guide the container after it has been released by the arm to a discharge part formed in the body of the vending apparatus.

Abstract: Disclosed is a constant pressure spraying apparatus in which the motor driven pump piston moves within a pump housing and valve assembly which are carried by a cap or closure for the fluid tank forming the reservoir of fluid to be pumped and sprayed. The cap structure is shaped so as to provide a drain sump for fluid leaking past the pump piston.

Abstract: The specification discloses a system and process for producing discrete chilled products having preselected weights from a semi-fluid mixture. The semi-fluid mixture is pumped along a distribution path to an extruding manifold which extrudes a plurality of parallel continuous lengths of the mixture. The continuous lengths are directed through a chilling station in a parallel relationship in order to chill and firm the lengths such that the lengths maintain their extruded cross-sectional configuration. A cutter periodically severs the continuous lengths at predetermined intervals to provide a plurality of discrete products having predetermined weights. The pumping rate, rate of travel through the freezer and periodic severing of the continuous lengths may be selectively varied in order to maintain any desired weight of the discrete products.

Abstract: A method for loading particulate matter in a vessel. More particularly, a method for distributing particulate matter, at substantially a constant rate, uniformly across a given area to promote the dense packing of said particulate matter.

Abstract: A syringe pump operated by a stepping motor to repetitively fill and empty a syringe cartridge over a plurality of operational cycles of successive fill stroke and pump stroke periods. The motor is driven by drive pulses from a digital pulse generation and control system, the pulse frequency establishing a predetermined fixed rate of fill during the fill stroke and being preselected, in accordance with desired output flow rate, to establish the rate at which the syringe is emptied during the pump stroke. The drive pulse rate during a fill stroke exceeds the maximum pulse rate during a pump stroke and, in order to maintain a proportional relationship between the preselected pumping rate and the actual pumping rate over each complete cycle of successive fill and pump strokes, the drive pulse frequency during each pump stroke is automatically increased to compensate for the time lost during each fill stroke.

Abstract: Chemical distribution system having a pressurized tank for causing flow of chemical to a plurality of appliances and having an apparatus for introducing a chemical into the tank from bulk storage and maintaining the pressure at a constant, predetermined value.

Abstract: A diverter valve assembly and priority control circuit for use in an ice distribution system having an ice source and first and second ice delivery stations, the valve assembly comprising a valve body having an inlet section communicable with the ice source, and first and second outlet sections communicable with the first and second delivery stations, respectively; the valve assembly including a valve body having a central valve chamber communicable with the inlet and outlet sections and having a rotatable valve element disposed therein; an electrically energized motor for selectively rotating the valve element whereby to selectively communicate ice being supplied from the ice source to selected of the ice delivery stations, and a control system for use with the valve assembly, whereby to assure against actuation of the valve element during the delivery of ice to the valve assembly.

Abstract: A control for a batch bin and a continuous loss bin system having a separate weight measuring device for each bin whose sum at transfer is used to establish continuously digitally desired weights at fixed intervals to be compared with the actual weight in the continuous loss bin to provide an error signal for a continuous feeder.

Abstract: A broadcast spreader having one or more spinners driven by hydraulic motors and a material delivery conveyor or auger driven by a hydraulic motor is provided with a hydraulic system including a flow and pressure-compensated variable displacement pump and pressure-compensated control valves respectively for the spinner and conveyor motors connected so that the volume of fluid delivered by the pump corresponds to the demands of the motors.

Abstract: Liquid reaction molding (LRM) shot size and ratio control is achieved using a programmable controller (microprocessor) to select on a first-come-first-served basis one mold from among several and to manipulate a plunger metering pump system by retracting each of a pair of pump plungers to the same position each time the system is reset and to decompress or reduce pressures after injection. Each and every shot is started from this uniform reset position. Later steps in the sequence are: taking the hydraulic slack out of each pump system by prepressurizing which is done by advancing each plunger from said position independently until each and all liquid systems reach a threshold pressure (which pressure may differ from one liquid system to the other), feeding the shot size or quantity of each liquid (i.e.

Abstract: An apparatus for discharging bulk material from a storage tank includes a support shaft; an impeller wheel mounted on the support shaft in the vicinity of the storage tank floor; and a stepping mechanism for intermittently moving the impeller wheel in either direction. The stepping mechanism has a ratchet wheel mounted on the support shaft and connected to the impeller wheel and a pawl mechanism cooperating with the ratchet wheel. A power cylinder, connected to a hydraulic circuit, is provided for moving the pawl mechanism. Further, there are provided a sensor arrangement for sensing the magnitude of the resistance of the bulk material to the motion of the impeller wheel and a control arrangement connected to the sensor arrangement and the pawl mechanism for reversing the direction of rotation of the impeller wheel when the resistance reaches a predetermined magnitude. The impeller wheel has at least one impeller vane associated with a discharge opening in the storage tank floor.

Abstract: A level control system involving both an apparatus and a method for a rotary feed hopper of the inverted, open-ended, truncated cone-type, wherein heavy paste-like viscous material which is fed into the large open upper end of the feed hopper is delivered or discharged through the small lower end of the hopper. A load meter in connected relation with the motor which drives the hopper senses the power required to drive the hopper and thus indirectly indicates the quantity of the material in the hopper, and consequently, the height or level of the material. When the load on the motor reaches a predetermined maximum the feed of material to the hopper is discontinued thus preventing overflow. When the load on the motor reaches a predetermined minimum the feed of material into the hopper is resumed.

Abstract: This disclosure relates to a machine for clearing bulk material from a bin table by moving therealong a movable support carrying a pivotally mounted rotatable clearing wheel including a first drive mechanism for moving the movable support and a second drive mechanism for rotating the clearing wheel and a control mechanism responsive to operational conditions of the second drive mechanism for controlling the operation of the first drive mechanism whereby the rotational speed of the clearing wheel may be increased or decreased as might be the speed of the movable support in dependence upon the resistance of the bulk material being offered to the clearing wheel during the rotation of the latter.

Abstract: A digital system wherein a wide variety of different electromechanical output control devices, e.g., stepping motor pump or solenoid actuated I.V. tube pincher, is driven by electrical output pulses of varible frequency and pulse width from a digital pulse generation and control system, the frequency and pulse width of the output pulses being selected and controlled by the system to establish drop flow rates with digital precision over an extremely wide dynamic range. Pulse width is determined by the relative states of a pair of digital counters in a digital memory, frequency being determined by a high, preferably non-integral, multiple of the desired drop flow rate. The equivalent of negative pulse width in the digital memory can be effectively utilized to expand the effective dynamic range of the memory for specified types of electromechanical output devices. A start up subsystem temporarily presets the initial pulse rate and speeds up early regulation.

Abstract: An injection molding machine comprising an injection cylinder; a displacement element axially disposed in the injection cylinder; one of the cylinder and displacement element being movable with respect to the other; an injection nozzle on one end of the injection cylinder and a feed device including a feed hopper and a plunger reciprocally mounted in the hopper on the other end of the cylinder; a pressure source for driving the plunger; and switches for varying the working position of the plunger, the plunger stroke, the stroke frequency of the plunger and the pressure of the pressure medium.

Abstract: A plurality of refrigeration units are successively charged with a liquid refrigerant which is dispensed by a positive displacement pump including a hydraulically actuated ram or piston slidably supported within a dispensing cylinder. An elongated tension coil spring extends parallel to the axis of the cylinder, and the piston carries a photosensing device which senses the helical turns of the spring when the piston is actuated to provide corresponding electrical pulses which are counted for precisely controlling the axial movement of the piston and the displacement of the refrigerant into each refrigeration unit. The length of the spring and the uniform spacing or pitch of the helical turns is automatically changed in response to changes in temperature of the refrigerant being dispensed to assure that each refrigeration unit is charged with precisely the desired weight of refrigerant regardless of changes in temperature of the refrigerant.

Abstract: Apparatus is described for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a master-slave velocity relationship between at least two metering pumps of the plunger or piston type which are velocity coupled and inject on a common programmed velocity profile that is fed into the pump control that is the master system. Each pump control system has a velocity feedback control loop (a closed loop system) and one signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the feedback master automatic control system (typically the poly isocyanate system).

Abstract: The throughput of a conveyor belt is controlled by a motor whose speed is established by the instantaneous state of an up/down counter. The counter is incremented upwardly by setpoint pulses representative of the desired mass flow rate, and downwardly by feedback pulses from a rate multiplier representative of the actual mass flow rate. When the actual mass flow rate is equal to the setpoint flow rate, the average number of setpoint pulses will equal the average number of feedback pulses with the result that the state of the counter will be stable with time. Speed control means for the motor maintains the belt speed at a level dependent upon the state of the counter. A variation between the actual and desired mass flow rates is manifested by a change in the average number of feedback pulses which results in a change in the state of the counter.