Several embodiments include a method of computing a phase composition ratio of a two-phase mixture in a pipe. For example, the phase composition ratio is a void fraction or a dryness fraction. The two-phase mixture can have one or more material substances that do not travel as a whole (e.g., at least two of solid phase, liquid phase, and gaseous phase or two liquid materials of different densities that do not mix). A load cell can measure, continuously, weight of the pipe and content of the pipe. Then, a computing system or a circuit can compute, continuously, a moving average of the continuously measured weight. The computing system or the circuit can compute a change in the phase composition ratio of the two-phase mixture based on the computed moving average.

Provided are systems and methods for accurate sensing of particle concentrations in fluids by employing a particle impactor system that allows for collection, growth and analysis of biological particles. The disclosed systems and methods make use of a pressure based flow sensor which permits the particle impactor system systems to accurately and reliably provide measurements of biological particle concentrations in the ambient environment. By incorporation of pressure sensors and pressure measurements into the flow measurement techniques, embodiments provide for the ability to use a particle impactor system to accurately measure environmental biological particle concentrations at a variety of atmospheric pressure conditions, such as at high altitude or with minimal perturbation from atmospheric weather conditions, without requiring recalibration or other adjustment of the sensors and control systems.

Provided are systems and methods for accurate sensing of particle concentrations in fluids by employing a particle impactor system that allows for collection, growth and analysis of biological particles. The disclosed systems and methods make use of a pressure based flow sensor which permits the particle impactor system systems to accurately and reliably provide measurements of biological particle concentrations in the ambient environment. By incorporation of pressure sensors and pressure measurements into the flow measurement techniques, embodiments provide for the ability to use a particle impactor system to accurately measure environmental biological particle concentrations at a variety of atmospheric pressure conditions, such as at high altitude or with minimal perturbation from atmospheric weather conditions, without requiring recalibration or other adjustment of the sensors and control systems.

A method for determining the flow rates of a fluid comprising a multi-component mixture of a gas and at least one liquid in a pipe, the method comprising the following steps: a. The temperature and pressure of the multi-component mixture is determined, b. the fractions of the multi-component mixture is determined based on at least two measured physical properties of the multi-components mixture and knowledge of the same physical property of the individual components of the multi-component mixture, c. the velocity of the multi component mixture is determined, d. based on the result from step a-c, the flow rate of the individual component of the fluid is determined, characterized by a method for determining the physical properties of at least one of the components of the multi-component mixture where e. an electromagnetic loss or phase measurement is performed, f. a statistical parameter related to the electromagnetic measurement is calculated, g. the said statistical parameter is compared to an empirical derived threshold value corresponding to the value of the statistical parameter when only one of the component of the multi component mixture is present, and h. the said physical properties of said fluid is determined if the statistical parameter exceeds the threshold value for the said component and used in step b-d to provide an improved value of the fractions, velocity and flow rate of the individual components of the multi-component mixture. An apparatus for performing the method is also disclosed.

The present invention controls convergent pressure of a closed space provided with a fluid resistance at high speed while an upstream valve provided on the upstream of the fluid resistance prevents overshooting. A pressure control system is provided with a fluid resistance in a channel forming a closed space and is configured to control pressure of the closed space by controlling an upstream valve provided on the upstream of the fluid resistance. The pressure control system includes a convergent pressure arithmetic unit and a valve controller. The convergent pressure arithmetic unit calculates convergent pressure of the closed space when the upstream valve is fully closed using at least one of upstream pressure and downstream pressure on the fluid resistance in the channel. The valve controller compares the calculated convergent pressure with a predetermined target convergent pressure and fully close the upstream valve based on the result of the comparison.

A fluid flow system may comprise an input line connected to a drilling system, one or more fluid flow lines connected to the input line, and an output line connected to the one or more fluid flow lines. The system may further include one or more valves disposed in each of the one or more fluid flow lines and one or more pressure sensors disposed in each of the one or more fluid flow lines. A method for controlling a fluid flow system may comprise moving a drilling fluid from a borehole into an input line of the fluid flow system, directing the drilling fluid through the input line into a fluid flow line, measuring a first pressure at a first pressure sensor in the fluid flow line, and measuring a second pressure at a second pressure sensor in the fluid flow line.

A fluid flow system may comprise an input line connected to a drilling system, one or more fluid flow lines connected to the input line, and an output line connected to the one or more fluid flow lines. The system may further include one or more valves disposed in each of the one or more fluid flow lines and one or more pressure sensors disposed in each of the one or more fluid flow lines. A method for controlling a fluid flow system may comprise moving a drilling fluid from a borehole into an input line of the fluid flow system, directing the drilling fluid through the input line into a fluid flow line, measuring a first pressure at a first pressure sensor in the fluid flow line, and measuring a second pressure at a second pressure sensor in the fluid flow line.

A flow generator (21) for a respiratory therapy system configured to deliver a breathable gas flow to a patient comprises a housing (27) comprising an inlet (28) and an outlet (25) and a gas flow path between the inlet (28) and outlet (25). An impeller is mounted within the housing (27) for rotation about an axis, the impeller configured to be rotationally driven by a motor to provide a gas flow along the gas flow path. Various embodiments are disclosed in which the flow generator (21) further comprises a sensor (23) mounted in the housing (27) in the gas flow path and configured to detect a property of the gas flow. The sensor (23) may be mounted in the outlet (25) so as to project into the gas flow path. Flow generator may comprise an axial inlet (28) and a tangential outlet (25). In another embodiment the sensor (23) may be mounted in the inlet (28).

Techniques to provide a unified system for fluid pressure and fluid flowrate measurement are described. Upstream and downstream transducers include piezo devices, and are in contact with a fluid flow, such as in a pipe within a metering device. In an example, a first signal is sent from the upstream transducer to a downstream transducer, and time-of-flight of the first signal is measured. A second signal is sent from the downstream transducer to the upstream transducer, and a time-of-flight of the second signal is measured. A flowrate of the fluid flowing within the passage is calculated, based on the times of flight of the first and second signals. An electrical signal is sent to the first transducer. Upon conclusion of the electrical signal, a pressure of the fluid flowing within the passage is calculated, based at least in part on time of decay of a second electrical signal generated by vibration of the first transducer.

A cleaning liquid supply device for supplying a cleaning device with cleaning liquid includes a chemical liquid inlet portion and a dilution water inlet portion, a first chemical liquid control unit fluidically connected to the chemical liquid inlet portion and the dilution water inlet portion, and a second chemical liquid control unit fluidically connected to the chemical liquid inlet portion and the dilution water inlet portion. The first chemical liquid control unit includes a first chemical-liquid-flow-rate control unit, a first dilution-water-flow-rate control unit, and a first mixing portion. The second chemical liquid control unit includes a second chemical-liquid-flow-rate control unit, a second dilution-water-flow-rate control unit, and a second mixing portion.