Abstract: A method and system for reducing pulsation in a gas compressor system. A side branch absorber, which may be installed on the lateral piping of either the suction or discharge side of the cylinders, has a hyperbolic horn at the input end. The hyperbolic horn in series with an inlet reducer substantially increases the mass reactance of the resonator and substantially reduces the resonator frequency or the required cavity volume for target resonator frequency. The horn is hyperbolic in the sense that it has a large diameter at the first end tapers to a smaller diameter near the second end.

Abstract: A method of reducing pulsations in a reciprocating compressor system, the system having nozzles between cylinders and filter bottles of the compressor system, the nozzles attaching at ports of the cylinders and filter bottles. A special insert is designed to be placed in one or more of the nozzle. The insert is generally cylindrical, but has a narrowed throat, a flared inlet end, and a flared outlet end. The insert dimensions, such as the inner diameter of the throat and the distance from the throat to the outlet end are calculated to reduce pulsations as well as provide pressure recovery.

Abstract: A method and system for reducing pulsation in a gas compressor system. A side branch absorber, which may be installed on the lateral piping of either the suction or discharge side of the cylinders, has a hyperbolic horn at the input end. The hyperbolic horn in series with an inlet reducer substantially increases the mass reactance of the resonator and substantially reduces the resonator frequency or the required cavity volume for a target resonator frequency. The horn is hyperbolic in the sense that it has a large diameter at the first end and tapers to a smaller diameter near the second end.

Abstract: An electronic, programmable device for controlling the motion of compressor valve elements, wherein the device receives an incoming signal from a velocity sensor located on a compressor valve; filters, amplifies, and processes the incoming signal by a control algorithm; and responds to the incoming signal by creating an output signal that produces an actuator force that is applied directly to a moving valve element and associated methodology.

Abstract: A method for reducing pulsation effects associated with the compressor nozzle of a positive displacement compressor system. A pulsation absorber, having a design like that of a side branch absorber, is installed on the cylinder valve cap or on the cylinder nozzle. The acoustic dimensions and placement of the pulsation absorber are designed to reduce the amplitude of the pulsations associated with the peak resonant frequency of the compressor nozzle response.

Abstract: A method and system for reducing pulsation in a gas compressor system. A pulsation control device, such as a filter bottle or side branch absorber, is installed at a port into some location on the compressor system. The pulsation control device has a choke tube with a variable cross-sectional area, such as by having multiple conduits that may be opened or closed or a diameter that may be varied. In operation, the cross sectional area of the choke tube is varied depending on the compressor speed.

Abstract: A method of reducing pulsations in a reciprocating compressor system, the system having nozzles between cylinders and filter bottles of the compressor system, the nozzles attaching at ports of the cylinders and filter bottles. A special insert is designed to be placed in one or more of the nozzle. The insert is generally cylindrical, but has a narrowed throat, a flared inlet end, and a flared outlet end. The insert dimensions, such as the inner diameter of the throat and the distance from the throat to the outlet end are calculated to reduce pulsations as well as provide pressure recovery.

Abstract: A method and apparatus for detecting the occurrence of surge or incipient surge in a centrifugal compressor is supplied. The centrifugal compressor has an inlet passage, an inlet passage wall and an impeller. When flowing a fluid through the centrifugal compressor thereby establishing a fluid flow in the inlet passage, the fluid flow is measured in the inlet passage proximate the inlet passage wall and proximate the impeller. The measurements may include detecting a reverse in the fluid flow direction, measuring a tangential component to the fluid flow, measuring a substantial decrease in the axial fluid flow, and/or measuring the fluid temperature. Fluid flow in the compressor can then be modified or controlled to prevent surge.

Abstract: An apparatus for determining a square root averaging error for a differential pressure orifice meter while measuring volumetric fluid flow in a closed medium including input circuitry that provides an input signal corresponding to the instantaneous differential pressure measured at the orifice plate and logic circuitry connected to receive the signals from the input circuitry for computing the square root averaging error for the orifice meter over a selected time interval. Also disclosed is an apparatus for measuring volumetric fluid flow in a closed medium that includes input circuitry for providing an input signal corresponding to a differential pressure at an orifice located within the closed medium and logic circuitry connected to receive the input signal, compute a square root of the corresponding differential pressure and provide an output signal corresponding to this square root.

Abstract: Acoustic pulsations in fluid transmission systems such as gas pipelines, engine exhaust systems and compressed air networks are suppressed by an acoustic filter comprising an enlarged pressure vessel with inlet and outlet conduits arranged such that conduit inlet and outlet openings are at the pressure node of standing pressure waves of the pressure vessel length resonant frequency and odd or even harmonics of the fundamental frequency. The inlet and outlet conduit openings are arranged such that the direction of convection flow and acoustic pulsation modulating flow is transverse to the instantaneous particle velocity of fluid resulting from acoustic pulsations existing in or excitable in the pressure vessel. Inlet and outlet conduits preferably open into the pressure vessel in a generally radial direction with respect to the central longitudinal axis of the vessel.

Abstract: A self-contained measuring device indicates three parameters necessary to the determination of operating performance of an electrical analog of a reciprocating gas compressor or pump. A first portion of the device provides for measuring any horsepower changes during operation as a percentage of the ideal operating conditions. A second portion of the device measures the discharge current from the analog cylinder. A third portion of the device measures the phase between a sinusoidal reference signal and a non-sinusoidal periodic driving signal. The phase measuring portion of the device is used primarily for initial setup of the analog, while the first and second portions are used both during setup and during normal operation.

Abstract: A relative horsepower indicator is used with an electrical model of a reciprocating gas compressor. A voltage representing the cylinder motion is modified and multiplied with a voltage representing the cylinder pressure. The result is calibrated to indicate one hundred percent cylinder horsepower when the model is operated under ideal conditions. The indicator is then used to indicate deviations from this ideal operating mode when the compressor model is used in a complete pumping system model.

Abstract: An apparatus for electrically simulating a reciprocating gas pump or compressor includes unidirectional devices for simulating intake and discharge valves. The volume of the reciprocating cylinder is modeled by a fixed capacitor coupled in a feedback arrangement with a variable gain amplifier. The gain of the amplifier is preferably controlled by the contents of a digital memory device, which varies the gain to simulate the pumping action of a compressor. The device provides voltage outputs representing the pressure and volume readings obtained in the compressor being simulated.

Abstract: An improved driving signal source for an electrical analog of a reciprocating compressor generates a variable frequency sinusoidal output. The ratio between the electrical frequency used by the analog and the mechanical frequency of the modeled compressor is controlled by a ratio set switch. Upper and lower limits of the mechanical speed are operator determined, and the electrical output frequency is varied between the corresponding upper and lower electrical analog frequencies. The instantaneous output frequency of the improved source is displayed in terms of mechanical compressor speed. The ratio of electrical to mechanical frequency can be changed independently of the upper and lower mechanical speed settings.

Abstract: An improved phase indicator measures the phase difference between a sinusoidal reference signal and a shaped signal having the same frequency. Means are provided for generating a first pulse which begins when the shaped signal makes a positive going transition past a selected voltage level, and ends when the reference signal makes a positive going transition past the zero reference level. A second pulse begins at the end of the first pulse, and ends when the shaped signal makes a negative transition past the selected level. The relative phase of the two signals are adjusted until the first and second pulses are the same length, which occurs when the two signals are 90 degrees out of phase. An indicator is then calibrated to read 90 degrees, and thereafter indicates the correct phase relationship between the two signals.

Abstract: A device suitable for use as an electrical analog of a unidirectional mechanical valve includes a three-terminal MOSFET. A sensing comparator has inputs coupled to the drain and source terminals of the FET, and an output coupled to the gate of the FET. A floating power supply allows the analog to operate independently of the circuit in which it is used. The FET will conduct current whenever the voltage from the drain to the source exceeds a threshold value, and will effectively act as an open circuit whenever the drain to source voltage is less than this threshold.

Abstract: Disclosed is an analog apparatus for simulating the low frequency pulsations and surge characteristics of centrifugal compressors and pumps and their interaction with piping systems. The apparatus includes a capacitor pump for simulating the pumping action of a centrifugal compressor. Voltages are applied to the input and output of the capacitor pump that are proportional to the section and discharge pressures of the compressor. The capacitor pump is driven electrically to simulate the action of the centrifugal compressor in a piping network.