A fan, in particular axial fan and preferably backward-curved radial fan, having an impeller equipped with blades, an electric motor for rotating the impeller and a device for determining the airflow when the impeller is rotating. The device for determining the airflow includes a volume flow measuring wheel arranged in the air flow, which is arranged upstream of the impeller on the inflow side. The air volume flow is calculated or derived from the rotational speed of the volume flow measuring wheel.

Method for operating a solar installation. The solar installation includes a solar field with direct evaporation accompanied by the generation of superheated live steam, a turbine for expanding the live steam, and a generator driven by the turbine for generating electrical energy. At least one valve is associated with the turbine by which the amount of live steam fed to the turbine is adjusted. The valve, or each valve, through which the amount of live steam fed to the turbine is adjusted such that an actual value of a live steam pressure occurring upstream of the turbine follows a reference value determined depending on a live steam temperature of the live steam upstream of the turbine.

Method for operating a solar installation. The solar installation includes a solar field with direct evaporation accompanied by the generation of superheated live steam, a turbine for expanding the live steam, and a generator driven by the turbine for generating electrical energy. At least one valve is associated with the turbine by which the amount of live steam fed to the turbine is adjusted. The valve, or each valve, through which the amount of live steam fed to the turbine is adjusted such that an actual value of a live steam pressure occurring upstream of the turbine follows a reference value determined depending on a live steam temperature of the live steam upstream of the turbine.

An in-line flowmeter for large diameter pipes includes an outer pipe with a diameter equal to that of the pipe to which it is coupled and an inner measuring tube carrying a portion of the flow, the flow through the measuring tube being sensed by a flowmeter associated with the measuring tube and with the total combined flow rate out of the in-line flowmeter calculated from the sensed flow through the measuring tube.

An in-line flowmeter for large diameter pipes includes an outer pipe with a diameter equal to that of the pipe to which it is coupled and an inner measuring tube carrying a portion of the flow, the flow through the measuring tube being sensed by a flowmeter associated with the measuring tube and with the total combined flow rate out of the in-line flowmeter calculated from the sensed flow through the measuring tube.

A fan, in particular axial fan and preferably backward-curved radial fan, having an impeller equipped with blades, an electric motor for rotating the impeller and a device for determining the airflow when the impeller is rotating. The device for determining the airflow includes a volume flow measuring wheel arranged in the air flow, which is arranged upstream of the impeller on the inflow side. The air volume flow is calculated or derived from the rotational speed of the volume flow measuring wheel.

A fan, in particular axial fan and preferably backward-curved radial fan, having an impeller equipped with blades, an electric motor for rotating the impeller and a device for determining the airflow when the impeller is rotating. The device for determining the airflow includes a volume flow measuring wheel arranged in the air flow, which is arranged upstream of the impeller on the inflow side. The air volume flow is calculated or derived from the rotational speed of the volume flow measuring wheel.

A volume fraction meter that includes a flow meter coupled to a flow line. The flow line includes a turned portion and the flow meter is positioned upstream from the turned portion with respect to a flow direction. The flow meter is configured to measure a volumetric flow rate of a multiphase fluid flowing in the flow direction through the flow line. The flow line includes a nozzle opening downstream the turned portion. The volume fraction meter also includes a strain gauge coupled to the flow line between the flow meter and the turned portion of the flow line. The strain gauge is configured to measure a bending strain on the flow line upon discharge of the multiphase fluid through the nozzle opening, such that the bending strain and the volumetric flow-rate provide inputs for determining a mixture density of the multiphase fluid.

In an embodiment, a method for measuring parameters of a liquid, where the method includes measuring pressure drops across a flow meter, measuring pressure upstream of the flow meter, and identifying at least one liquid parameter based, at least in part, on a correlation of a change in a multiphase flow parameter to pulse output. In an additional embodiment, a measuring apparatus for measuring parameters of a liquid, where the measuring apparatus includes an electronic control operable to measure pressure drops across the measuring apparatus, measure pressure upstream of the measuring apparatus, and correlate a change in a multiphase parameter to measured pulse output of the measuring apparatus.

A radial fan has a housing with a motor-drivable fan wheel. The fan wheel generates an air volume flow during operation. The housing has a blow-out portion (4) with an impeller (5). The impeller (5) has a plurality of impeller blades (7) spaced apart in the circumferential direction. The impeller (5) is driven by the air volume flow generated by the fan wheel.