In a flow meter with a displacement meter (1) a parallel-connected pressure difference sensor (3) has a bypass channel (8) which frees a connection between the inflow side and the outflow side (4, 5) when a piston (7) butts against a maximum stroke stop (9). In the bypass channel (8) is a check valve (11) which prevents the backflow from the outflow side to the inflow side (5, 4) and thus enables a return of the piston (7) purely due to pressure.

A device for measuring through-flow processes of fluids. The device includes an inlet, an outlet, a flow housing in which a fluid flows, a drivable displacement meter in the flow housing, a bypass line which bypasses the drivable displacement meter, a pressure difference sensor in the bypass line and in the flow housing, an evaluation and control unit which controls the drivable displacement meter based on a pressure difference existing at the pressure difference sensor, and a cooling channel in the flow housing which has a coolant flow therethrough.

A device for measuring flow processes of fluids includes an inlet, an outlet, a housing in which is arranged a drivable positive displacement flow meter which includes a positive displacement chamber in which a driven impeller is rotatably arranged, a first supply duct connecting the displacement chamber with the inlet, a first discharge duct connecting the displacement chamber with the outlet, a first inlet port, a second supply duct connected to the inlet, a displacement flow meter bypass with a differential pressure sensor, and an evaluation and control unit which controls the displacement flow meter based on a differential pressure applied to the pressure sensor. Cavitation wear of the positive displacement meter is reduced by the first supply duct opening into a front of the displacement chamber via the first inlet port, and the second supply duct opening into a rear of the displacement chamber via a second inlet port.

A device for measuring flow processes of fluids. The device includes an inlet, an outlet, a drive unit, a positive displacement flow meter which is driven by the drive unit, the positive displacement flow meter including a positive displacement chamber, a supply duct which fluidically connects the positive displacement chamber to the inlet, a discharge duct which fluidically connects the positive displacement chamber to the outlet, a bypass which bypasses the positive displacement flow meter, a differential pressure sensor arranged in the bypass, and an evaluation and control unit which provides a control of the positive displacement flow meter based on a differential pressure applied to the differential pressure sensor. The supply duct and the discharge duct each rise in a fluid flow direction.

A device for measuring flow processes of fluids includes an inlet, an outlet, a housing, a drivable positive displacement flow meter arranged in the housing, the displacement flow meter including a positive displacement chamber formed therein in which at least one driven impeller is rotatably arranged, a first supply duct fluidically connecting the displacement chamber with the inlet, a first discharge duct fluidically connecting the displacement chamber with the outlet, a first inlet port via which the first supply duct opens into a front of the displacement chamber, a second supply duct fluidically connected to the inlet, a displacement flow meter bypass with a differential pressure sensor arranged therein, and an evaluation and control unit which controls the displacement flow meter based on a differential pressure applied to the pressure sensor. The second supply duct opens into a rear of the displacement chamber via a second inlet port.

A device for measuring flow processes of a measuring fluid. The device includes an inlet, an outlet, a positive displacement housing, a drive unit, a positive displacement flow meter driven by the drive unit arranged in the positive displacement housing, a bypass which bypasses the positive displacement flow meter, a differential pressure sensor arranged in the bypass; and an evaluation and control unit which controls the positive displacement flow meter based on a pressure difference existing at the differential pressure sensor. The drive unit includes a canned motor which includes a drive shaft, a rotor, and a stator with windings, and a can which separates an inner chamber, which is filled with the measuring fluid and which holds the drive shaft and the rotor, from an outer chamber, which holds the stator.

A device for measuring through-flow processes of fluids. The device includes an inlet, an outlet, a flow housing in which a fluid flows, a drivable displacement meter in the flow housing, a bypass line which bypasses the drivable displacement meter, a pressure difference sensor in the bypass line and in the flow housing, an evaluation and control unit which controls the drivable displacement meter based on a pressure difference existing at the pressure difference sensor, and a cooling channel in the flow housing which has a coolant flow therethrough.

A device for measuring flow processes of fluids. The device includes an inlet, an outlet, a drive unit, a positive displacement flow meter which is driven by the drive unit, the positive displacement flow meter including a positive displacement chamber, a supply duct which fluidically connects the positive displacement chamber to the inlet, a discharge duct which fluidically connects the positive displacement chamber to the outlet, a bypass which bypasses the positive displacement flow meter, a differential pressure sensor arranged in the bypass, and an evaluation and control unit which provides a control of the positive displacement flow meter based on a differential pressure applied to the differential pressure sensor. The supply duct and the discharge duct each rise in a fluid flow direction.

A drive and control device for a throughflow measurement device. The drive and control device includes an electric drive unit, a connection housing connected to the electric drive unit, a main board, and an attachment structure to position the main board with respect to the electric drive unit. The attachment structure includes at least one board retaining element to which the main board is attached, and an attachment element to which the electric drive unit is attached. The attachment element includes guide rails which position the at least one board retaining element when the at least one board retaining element is pushed onto the guide rails.

A system and method for improved flow measurements for LCG, such as liquid petroleum gas (LPG), is disclosed. Embodiments of the present technology detect the presence of a vapor in a fluid flowing in a mass flow meter. A control valve is then adjusted to provide enough back pressure to prevent the measured liquid from flashing and to reduce the presence of vapor in the fluid flowing in the mass flow meter. By keeping the fluid in liquid form, the present technology reduces the vapor flowing in the mass flow meter, increasing the accuracy of mass flow and other measurements. Utilizing a similar principle of vapor detection, embodiments of the present technology provide for improved average parameter value calculation, such as average density calculations and equivalent liquid volume calculations.