Abstract:
A high-pressure homogenizer, comprising: a plurality of pumping pistons (2a, 2b), for feeding a liquid to be homogenized toward a manifold (6), each piston being associated with a respective oil hydraulic cylinder; a homogenizing valve positioned downstream of said pumping pistons (2a, 2b); and an electronic system (5) for controlling and regulating said pumping pistons (2a, 2b), which controls the law of motion of each individual piston (2a, 2b) independently. Said electronic regulation system (5) is connected to a transducer placed on the manifold (6) to regulate the delivery of oil to the individual cylinders (3a, 3b) according to the pressure, sensed in the manifold (6), of the liquid to be homogenized pumped by said pistons (2a, 2b) in order to maintain a stable flow rate and pressure.
Abstract:
Systems and methods for operating a linear pump system involve operating a linear motor system; reciprocating a linear pump and a motor control module that issues commands and a control logic input to the linear motor system. The linear motor system is operated to reciprocate an output shaft between first and second reversal positions. The linear pump is reciprocated with the output shaft to produce a flow of material. A pump reversal command reverses direction of the output shaft. A torque command controls speed of the output shaft. The control logic input reciprocates the output shaft at speeds to produce a constant output condition of the flow of material. The motor control module adjusts the torque command to operate the output shaft at an increased speed above what is necessary for the constant output condition for a temporary time period beginning when the reversal command is issued.
Abstract:
A feedback control loop for a high pressure pump modifies the accumulator velocity and pressure during solvent transfer. The accumulator velocity is adjusted to maintain the system pressure equal to the expected pressure to thereby eliminate the effect of the flow deficit created by a thermal effect.
Abstract:
The invention calls for two bellow-type pumps working alternately with overlapping strokes to pump a liquid at a constant rate. The speed of motion of the drive to each of the two pumps over the pump stroke is changed in such a way that, in those parts of the delivery stroke in which the pumping rate is below the required value, the stroke speed is increased and, in those parts in which the pumping rate is above the required value, the stroke speed is decreased so that the overall pumping rate corresponds to that required. To this end, the drive to each of the pump is controlled by a computer in which the characteristic curve of each of the two pumps is stored, superimposed on the characteristic curve for the drive, to give the required constant liquid-pumping rate. The computer also receives data on the total amount of liquid which is metered into for instance a stream of fluid.
Abstract:
A method includes driving a fluid pumping unit having a plurality of pumping cylinders via a plurality of hydraulic cylinders respectively of a hydraulic power unit. The method further includes controlling activation of the hydraulic power unit such that each stroke of the corresponding piston assembly between the top dead center and the bottom dead center follows a corresponding trapezoidal velocity profile with respect to a time duration. Controlling activation includes controlling flow of a hydraulic fluid in the hydraulic power unit so as to control the corresponding trapezoidal velocity profile with respect to the time duration of the corresponding piston assembly to obtain a predefined flow rate of the fluid medium from the pumping unit.
Abstract:
Eine Vorrichtung zur Steuerung einer Kolbenpumpeneinheit mit wenigstens zwei phasenversetzt arbeitenden Kolben-Zylindereinheiten für die Flüssigkeitschromatographie und eine Kolbenpumpeneinheit mit einer derartigen Steuervorrichtung. Um einen pulsationsarmen Fluss unter hohem Druck fördern zu können, werden die Antriebe für die Kolben so gesteuert, dass während der Ansaugphase des ersten Kolbens der zweite Kolben fördert und während der Ansaugphase des zweiten Kolbens der erste Kolben fördert. Die Steuervorrichtung korrigiert Schwankungen (45) des Systemdrucks (40) während des Umschaltens von einer Kolben-Zylindereinheit auf die jeweils andere Kolben-Zylindereinheit. Die Schwankungen (45) sind eine Folge der Abkühlung des während einer Vorkompressionsphase im Arbeitskolben adiabatisch erwärmten flüssigen Mediums. In der Vorkompressionsphase entspricht der theoretische isotherme Druckanstieg (43), bei dem der Systemdruck (40) zum Zeitpunkt (t 1 ) erreicht würde, nicht dem realen Druckanstieg (42), der eine zusätzliche Druckerhöhung beinhaltet, so dass der Systemdruck (40) bereits zum Zeitpunkt (t 2 ) erreicht wird. Die zusätzliche Druckerhöhung resultiert aus einer adiabatischen Erwärmung der Flüssigkeit durch Kompressionsarbeit. In der Steuervorrichtung wird die Zeitdifferenz Δt = t 1 - t 2 aus dem Druckverlauf im Messintervall t 3 bis t 4 extrapoliert um eine Korrektur der Kolbengeschwindigkeit zu berechnen und die Schwankungen zu korrigieren.
Abstract:
A solvent supply system for supplying a composite solvent is described. The solvent supply system comprises a first supply flow path with a first pump unit, the first supply flow path being adapted for supplying a flow of a first solvent to a mixing unit, the first pump unit operating periodically, and a second supply flow path with a second pump unit, the second supply flow path being adapted for supplying a flow of a second solvent to the mixing unit, the second pump unit operating periodically. The mixing unit is adapted for mixing the first and the second solvent and for supplying a composite solvent. The solvent supply system further comprises a control unit adapted for controlling operation of the first and the second pump unit, the control unit being adapted to prevent at least one of a predefined phase relation and a predefined frequency relation between the first pump unit and the second pump unit.
Abstract:
A pumping system including a plurality of pumps each having a pump fluid outlet, a drive shaft, a prime mover, and fluid displacing members operatively coupled with the drive shaft. A common fluid conduit may be fluidly coupled with each pump fluid outlet. A control system of the pumping system includes position sensors operable to generate information relating to phase and/or speed of each pump, pressure sensors operable to generate information relating to fluid pressure spikes, and a controller in communication with the position and pressure sensors. The controller is operable to cause the prime movers to adjust the phasing of the pumps with respect to each other, based on the information relating to fluid pressure spikes, and synchronize the speed of the pumps.
Abstract:
Die Erfindung betrifft das Gebiet von Flüssigkeitspumpen in medizinischen Behandlungsvorrichtungen, insbesondere Dialysegeräte. Der Erfindung liegt die Aufgabe zu Grunde, Verfahren und Vorrichtungen derart auszubilden, dass die Arbeitsdrücke oder Flussraten der Flüssigkeitspumpen gewünschte Verläufe annehmen, insbesondere konstante Werte oder kontrollierten Profilen folgen. Gelöst wird diese Aufgabe, in dem der Arbeitspunkt einer peristaltischen Schlauchrollenpumpe aufgrund des Drehwinkels des Pumpenrotors eingestellt wird oder dadurch, in dem der Arbeitspunkt einer Zentrifugalpumpe einem Profil folgend eingestellt wird.