A solenoid valve control system comprising a solenoid valve drive circuit applying a drive current to the solenoid valve; a pressure data calculation unit calculating a pressure data including a band and a cycle of pressure fluctuation from a pressure value; a pressure hysteresis calculation unit calculating a difference between the pressure value when the drive current value is increased and the pressure value when the drive current value is decrease as a hysteresis amount; a vibration determination unit determining whether or not the pressure data is included in an area outside the pressure data range, which is outside a first predetermined range; a hysteresis determination unit determining whether or not the pressure hysteresis amount is included in an area outside the pressure hysteresis amount range, which is outside a second predetermined range; and a drive frequency adjustment unit adjusting a drive frequency based on the determination result.

The present invention recites a control method for a controller of a water faucet particularly for a battery operated water faucet. The method comprises the step to detect the change of back electromagnetic voltage in the driving circuit. The present invention also provides a control circuit of a controller for a water faucet particularly for a battery operated water faucet. The controller comprises a controller body having an electric solenoid formed therein, a sensor to emit and receive an Infrared signal so as to generate and transmit an operating signal, a microprocessor to receive and process the operating signal from the sensor, a driving circuit to control the switching ON-OFF of the solenoid, and a detecting means associated with a detecting circuit to detect the change of back electromagnetic voltage of the power applied to the solenoid so as to accurately control the water flow.

A system and method are provided for in-line processes of blending butane into gasoline streams, and for blending butane into a gasoline stream at any point along a petroleum pipeline. The invention additionally provides a method for measuring the vapor pressure and vapor to liquid ratio of the gasoline, both upstream and downstream of the blending operation, as well as the sulfur content of the butane entering the blending operation. The blending operation can be controlled to ensure that the blended gasoline meets EPA requirements for vapor pressure and sulfur content of gasoline. The invention further provides a method for accessing and monitoring the operation off-site.

A system and method are provided for in-line processes of blending butane into gasoline streams, and for blending butane into a gasoline stream at any point along a petroleum pipeline. The invention additionally provides a method for measuring the vapor pressure and vapor to liquid ratio of the gasoline, both upstream and downstream of the blending operation, as well as the sulfur content of the butane entering the blending operation. The blending operation can be controlled to ensure that the blended gasoline meets EPA requirements for vapor pressure and sulfur content of gasoline. The invention further provides a method for accessing and monitoring the operation off-site.

Disclosed is a method in which the propulsive power of a drive nozzle (2) is controlled by means of a programmable logic control device (24) having an adjustable internal controller (25) in dependence upon the rotational frequency of a turbocharger rotor (1) detected by a speed sensor (26). Parameters necessary for control are determined empirically in a tuning run which includes tuning the controller (25) to a proportional control action with high gain Kp and inputting the nominal balancing speed as target value for the controller (25), monitoring and comparing the actual speed with the target value. If the actual speed exceeds the set target value, halving the gain Kp of the controller (25) and repeating the run until the actual speed is below the set target value. Then it includes approximating the actual speed to the target speed by generating an additional target value, additively applying the additional target value to the target value, and incrementing or decrementing the additional target value until the target speed of the turbocharger rotor (1) is reached.

A mass flow controller (10) comprises a fluid inlet (15) and at least one first flow meter (11) to measure a first flow rate (F.sub.1) and to output a first flow signal (FS.sub.1); at least one second flow meter (12) to measure a second flow (F.sub.2) rate and to output a second flow signal (FS.sub.2); a control device (13) connected to said first and second flow meters (11,12) and configured and arranged to generate a control signal (C); and at least one control valve (14) connected to said control device (13) to control a total flow rate (F.sub.out) through the mass flow controller (10) in response to the control signal (C). The control signal (C) is generated as a function of both the first and second flow signals (FS.sub.1,FS.sub.2) such that the mass flow controller's (10) sensitivity to perturbations of said inlet pressure is minimized.