Abstract: The present invention relates to a method for determining a flow rate indicator relating to the output flow rate of one or more activated pumps of a pumping station. The pumping station includes a well to be at least partially emptied by the pumps and an inlet through which inflow can be supplied into the well. The method includes the step of determining, using a computational device, an operating condition relating to the activated pumps. The pumps are temporarily deactivated and an inflow rate indicator relating to the inflow is determined using the computational device, responsive to the determination of the operating condition. The method further includes the step of determining, using the computational device, the flow rate indicator using the determined inflow rate indicator. The present invention is equally applicable to a well to be at least partially filled by the pumps.

Abstract: An electromagnetic valve, which is provided between an intake port of a compressor body and a pneumatic line at an intermediate position of an intake pipe, is opened/closed by a control unit. Communication between the intake port of the compressor body and the pneumatic line is permitted when the valve is open, and is blocked when the valve is closed. In a start-up control of the compressor body, the electromagnetic valve is opened, permitting communication of the pneumatic line in the plant with the intake port of the compressor body for power supply to an electric motor to drive an orbiting scroll. Rattling of the orbiting scroll by an amount equal to the axial gap (play) is suppressed before starting a compression operation.

Abstract: A device and method are disclosed for driving an electromagnet for operating a pump. The electromagnet includes a primary winding and a moving element that is attracted within the primary winding when an energizing current is higher than a first threshold value. The moving element lets a liquid dose into an external hydraulic circuit depending on the a travel of the moving element. A control logic unit detects an energizing current to provide the energizing current to the primary winding until the energizing current assumes a second threshold value, depending on a value of the liquid dose to let into the external hydraulic circuit. The second threshold value is higher than the first threshold value and not higher than a third threshold value in correspondence of which the moving element arrives at a stop.

Abstract: The invention relates to an apparatus including a pump 1 driven by an electronically controlled electric motor 3 with a pump controller 4 and a valve 2 operated by an electronically controlled drive 10 with a valve controller 11, the valve controller 11 being partially or fully integrated in the pump controller 4.

Abstract: A method for detecting the occurrence of surge in a centrifugal compressor includes the step of calculating a time rate of change of a discharge pressure of the fluid discharged from the compressor. In one preferred embodiment, the time rate of change of the discharge pressure is calculated by initially setting PREV PRESS and RATE PRESS variables equal to zero (0), and commencing a RATE PRESS subroutine having a time limit for cycling therethrough. The RATE PRESS subroutine includes the steps of obtaining a discharge pressure reading for the fluid discharged from the compressor, subtracting the discharge pressure reading from the PREV PRESS variable to establish the RATE PRESS variable, and resetting the PREV PRESS variable equal to the value of the discharge pressure reading. After the RATE PRESS variable has been determined, the RATE PRESS is compared with an acceptable set time point rate of change for the discharge pressure.

Abstract: A method of starting a variable-speed pump turbine or a variable-speed pump driven by a variable-speed generator motor or a variable-speed motor connected to an electric power line in parallel therewith. The generator motor or the motor is first operated at low speed with the guide vanes or the delivery valve fully closed. The low speed is lower than a stable starting speed of the pump turbine or the motor but high enough to prevent backward flow of water into the pump turbine or the pump. After the operation is set at the low speed, the guide vanes or the delivery valve are opened and the opening degree is gradually opened until the speed is increased to a speed optimum for the steady operating condition of the pump turbine or pump. This method effectively suppresses abrupt increase in the pump input power required for the driving of the pump turbine or the pump, whereby unfavorable effect on the electric power line is avoided advantageously.

Abstract: A control system is disclosed for a noninteracting control and protection of a dynamic compressor having rotating vanes.The method consists of a junction of a few control circuits for controlling the performance of a dynamic compressor, for protecting compressor from approaching dangerous zones of operation, and for maintaining a required mass flow rate of a gas through the compressor.An automatic control system based on using the above method is distinguished by its simplicity, great transient and steady state precision and high reliability of surge protection.

Abstract: A method is disclosed for a cascade control of a dynamic compressor to maintain a constant mass flow rate to a process. The method consists of a successive junction of control loops for controlling the speed of rotation, the pressure in the delivery, and the mass flow rate; the output signal of each outer loop being the input signal for the inner loop and each of the loops containing a compensating element to reduce the effects of large time constants of all previous loops.An automatic control system based on using the above method, distinguished by its great static and dynamic precision in maintaining a controlled parameter, and by the high reliability of protection of the compressor from surge, and protection from a dangerous increase of the speed of rotation and of a dangerous increase of the discharge pressure.

Abstract: The speed of an engine driven pump is sensed and compared with the desired maximum operating speed to detect overspeed. The discharge of the pump is controlled by a variable flow rate controller. When an overspeed condition exists, a command signal is sent to the discharge controller to reduce flow by a discrete decrement. The control signal is blocked after activating the controller for a preselected time interval. During the blocking interval the engine speed is maintained substantially at the operating speed by cyclical reduction of the power input thereto.