Abstract: A method and apparatus for determining a fluid level and/or output flow during operation of a centrifugal pump, are provided, which may be used for production of gas and/or oil from a well, and include a vector feedback model to derive values of torque and speed from signals indicative of instantaneous current and voltage drawn by the pump motor, a pump model which derives values of the fluid flow rate and the head pressure for the pump from torque and speed inputs, a pumping system model that derives, from the estimated values of the pump operating parameters, an estimated value of fluid level and other pumping system parameters. Controllers responsive to the estimated values of the pumping system parameters control the pump to maintain fluid level at the pump input, near an optimum level, or within a safe operating range and/or output flow from the pump.

Abstract: A system for controlling operation of a progressing cavity pump to maintain the motor operating under power disturbance conditions. For a blackout condition, a backspin controller uses regenerative power to provide controlled deceleration of the pump, counteracting backspin and preventing backspinning freely. For a brownout condition, a power dip controller weakens the motor field to maximize pump production consistent with reduced input power availability. For a phase loss or voltage imbalance condition, a phase loss controller reduces motor power output to keep drive system output power at or below single phase capacity.

Abstract: A method and apparatus for managing power demand of a motor in a cyclic load system having a rotational mass is provided. Flat power draw is achieved through continuous manipulation of the motor torque as a function of feedback velocity while using the rotational mass of the cyclic load as a means to store/retrieve energy. Alternatively, reduced variation of power draw is accomplished through continuous manipulation of motor velocity as a function of feedback torque. The methods and apparatus are used in systems where zero or reduced power demand variation is either required or desired, such as in generator powered applications.

Abstract: An apparatus and method for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, include a linear rod pump having a mechanical rack and pinion drive arrangement, adapted for attachment to a pumping mechanism, such as the polished rod at the top of a rod string in a hydrocarbon well. The rack gear, of the rack and pinion drive arrangement, is adapted for connection to, and movement with, the polished rod. The pinion gear does not translate with the rack gear, and is driven by a reversible motor for affecting up and down reciprocating motion of the rack gear and pumping mechanism. Some forms of the invention include a compressible gas counter-balance arrangement. Some forms of the invention include an electronic drive configured for dealing with electric power generated by the motor during a portion of the pumping cycle.

Abstract: A method and apparatus for managing power demand of a motor in a cyclic load system having a rotational mass is provided. Flat power draw is achieved through continuous manipulation of the motor torque as a function of feedback velocity while using the rotational mass of the cyclic load as a means to store/retrieve energy. Alternatively, reduced variation of power draw is accomplished through continuous manipulation of motor velocity as a function of feedback torque. The methods and apparatus are used in systems where zero or reduced power demand variation is either required or desired, such as in generator powered applications.

Abstract: A method and apparatus are provided for estimating and/or precluding stick-slip, or other oscillatory or resonant behavior, through use of a virtual transducer, which precludes the need for having sensors located adjacent to a driven element of the system, or adjacent contact surfaces at which the stick-slip relative motion may occur. Parameters measurable at a drive mechanism are utilized for controlling a system in a manner which precludes stick-slip, or other oscillatory or resonant behavior, of the driven element. Relative motion between contacting surfaces in the driven element, prone to stick-slip behavior, is controlled such that, after sufficient force is applied by the drive element to overcome static friction forces between the contacting surfaces and break them free from one another, relative motion between the surfaces is maintained at a high enough relative speed that the surfaces are precluded from statically contacting one another, so that stick-slip behavior is precluded.

Abstract: An improved method and apparatus are provided for constructing and operating a linear actuator, and equipment incorporating a linear actuator, by operatively connecting a pressure biasing pneumatic arrangement between the driving member and the driven member of a mechanical linear actuator for applying a unidirectional biasing force between the driving and driven members, along an axis of motion, regardless of the location or movement of the driving and driven elements with respect to one another along the axis of motion. The pneumatic biasing arrangement is also configured, connected and operated to reduce the force which must be exerted by the driving and driven members in extending and retracting the linear actuator. The pneumatic biasing arrangement may further be configured for preferentially aiding extension or retraction of the actuator.

Abstract: A rod pump control system includes a parameter estimator that determines from motor data parameters relating to operation of the rod pump and/or downhole dynamometer card without the need for external instrumentation, such as down hole sensors, rod load sensors, flow sensors, acoustic fluid level sensors, etc. In one embodiment, instantaneous motor current and voltage together with pump parameters are used in determining rod position and load. The rod position and load are used to control the operation of the rod pump to optimize the operation of the pump. Also disclosed in a pump stroke amplifier that is capable of increasing pump stroke without changing the overall pumping speed, or in the alternative, maintaining the well output with decreased overall pumping speed.

Abstract: A lighted status indicator for a contact (circuit breaker, switch or fuse) with a distinctive color associated with each position of the circuit breaker. The lighted status indicator is composed of a multi-color light source (usually an LED) together with an electronic circuit that changes the color of that light source, depending upon the status (or position) of the circuit breaker, switch, or fuse.

Abstract: A control system for the operation of a centrifugal pump which may be used for production of gas and/or oil from a well. The control system includes vector feedback model to derive values of torque and speed from signals indicative of instantaneous current and voltage drawn by the pump motor, a pump model which derives values of the fluid flow rate and the head pressure for the pump from torque and speed inputs, a pumping system model that derives from the estimated values of the pump operating parameters an estimated value of a pumping system parameter and controllers responsive to the estimated values of the pumping system parameters to control the pump to maintain fluid level at the pump input near an optimum level.

Abstract: A method is provided for sizing an environmental control system for controlling a temperature of a target. The method comprises the steps of: identifying the target that is to be temperature controlled by the environmental control system; selecting a desired temperature of the target that is to be temperature controlled; and determining optimal characteristics of the environmental control system. Preferably, the step of determining optimal characteristics of the environmental control system includes referring to a nomograph that charts numerical relationships of a plurality of variables. Preferably, variables charted on the nomograph include a temperature of discharge air that is to be discharged from the environmental control system, a temperature of ambient air surrounding the target, a distance between a discharge portion of the environmental control system and the target, and a volumetric flow rate of the discharge air.

Abstract: A vent structure comprises an inlet-connector section, an outlet section, and a transition section between the inlet-connector section and outlet section. The inlet-connector section is at an inlet end of the vent structure and is adapted for connection with an inlet duct from which the vent structure receives a flow of air. The outlet section is at an outlet end of the vent structure and includes an outlet slot that is adapted to direct the flow of air into a room. The transition section has a flared portion that diverges in cross-sectional area as it extends generally toward the outlet section. The transition section has a constricted portion located between the inlet-connector section and the outlet slot. The constricted portion is also located substantially centrally within a plane that is generally perpendicular to a direction of air flow.

Abstract: A vent structure with a slotted rectangular outlet includes a cylindrical connector section to mate with a cylindrical duct, a flared and curved transition section, and a rectangular outlet section. The structure is formed in such a manner that turbulence is minimized in air flowing through the structure to thereby lessen the generation of airflow noise. The structure is sized and shaped to fit within a stud wall formed by conventionally sized studs positioned at a typical spacing. The structure includes a mounting plate with a mounting channel to receive an extendible mounting bracket, the ends of which are fastened to studs between which the structure is mounted.

Abstract: A digital current regulator for controlling the operation of an inductance device such as an AC motor. A plurality of independently controllable insulated gate bipolar transistors are selectively enabled to vary the instantaneous phase and magnitude of current applied to an AC motor. To minimize induced back EMFs during current switching operations, a number of safeguards are utilized. Switching between adjacent states only is provided to minimize the magnitude of instantaneous current changes. A "ready blocking" function limits the maximum switching frequency to avoid significantly derating the switching device capabilities, while a "time out" feature assures system operation above at least a minimum switching frequency to further minimize the magnitude of instantaneous current changes. A time hysteresis function is provided to avoid switching device response to false feedback control signals.

Abstract: A modular air conditioning system with adjustable capacity includes a cooling module, a heating module, and a blower module which can be assembled in any of a plurality of configurations, including a vertical downflow configuration, a vertical upflow configuration, or a horizontal configuration, using the same set of modules. The same set of modules can be operated over a range of cooling capacities by employing a condensing unit of the required capacity connected to the cooling module and by adjusting the airflow volume rate of air transported through the system. A movable restrictor plate is positioned in partial covering relation to a discharge opening of the blower module and is adjusted to achieve the required airflow volume rate.

Abstract: A position monitoring device for accurately determining a plurality of distances, velocity or acceleration along a line using a plurality of electromagnets. The position monitoring device includes an ultrasound transducer disposed along a line, an ultrasound generator to provide an ultrasound wave pulse along the ultrasound transducer and a plurality of electromagnets disposed along the line at selected positions. The electromagnets generate a magnetic field which interacts with the ultrasound pulse to generate a reflected pulse. A sensor measures the time lapse between generation of the initial pulse and receipt of the reflected pulse, and electronic components convert the time lapse interval to a position measurement.

Abstract: A conveyor system for transporting a succession of thin flexible sheets such as plastic bags from a bag forming device to a bag stacking device. The conveyor system includes a first conveyor having vacuum holes for holding the bags in place, with portions of the bags extending beyond the conveyor's edges. The system further includes bag support apparatus such as a pair of auxiliary conveyors located alongside the first conveyor and supporting the overhanginig portions of the bags. The auxiliary conveyors terminate short of the end of the first conveyor, such that for a predetermined distance the overhanging portions of the bags are unsupported, thus permitting a bag stacking device to lift the bags and deposit them onto a stack.

Abstract: A linear resolver utilizes multiple pairs of nulled coil sets arranged co-linearly for sensing the position of multiple edges of a magnetically permeable object. An excitation coil produces an alternating magnetic field which is normally weakly coupled to the nulled coil sets across a magnetic gap. As the object covers the area of the gap, the coupling between the excitation and the individual coils in a nulled coil set is increased. Each nulled coil set produces an output which varies cyclically with increasing coverage of the object. The two nulled coil sets in each pair of nulled coil sets are offset from each other so that their cyclical outputs are offset by one quarter cycle, or 90.degree. with respect to the area of coverage by the object. Detection means are provided which resolve the outputs from a pair of nulled coil sets to precisely determine the position of the object edge. Each nulled coil pair is processed separately by the detection means so that multiple edges can be detected.

Abstract: A plurality of magnetic elevator devices disposed along the sides of a vertical stack of magnetizable steel objects, such as sheets or rods, separates them and raises the uppermost one vertically. Sensing devices in a control system sense when the object reaches a transport position and actuate a transport mechanism to move to another location. Each magnetic elevator device comprises a magnetic structure (permanent magnet or electro-magnet) and a pair of elongated, vertically extending, laterally spaced apart contact rails of opposite magnetic polarity which engage the edges of the stacked objects. Each contact rail comprises a magnetic portion having a point of minimum reluctance near its top and a non-magnetic, low-friction surface portion (plastic or stainless steel) which slidably engages each object to guide it and to hold it spaced from the magnetic portion.

Abstract: A motion converter is disposed at the input to a work station to convert the constant velocity of sheet material as it is payed out from a roll into a cyclic, stop and go motion. The motion converter includes a pair of actuators containing electromagnets and these are alternately energized to attract the sheet material first against a contoured surface and then a flat surface. Sheet material accumulates in a serpentine path within the motion converter when attracted toward the contoured surface and it is expelled rapidly therefrom when attracted toward the flat surface. A programmed position control operates the electromagnets in response to position feedback signals from sensors on the motion converter.