A method an apparatus for measuring a base condition volumetric flowrate of a pipeline gas flowing through a pipeline in which a pipeline gas flowrate is measured by a pipeline gas flowmeter; a volumetric correction ratio is derived by: measuring a sample gas flowrate of sample gas (12) tapped from the pipeline, measuring an energy flowrate of the sample gas (12), measuring a heating value of the sample gas (12), and measuring a base condition density of the sample gas (12); and the base condition volumetric flowrate of the pipeline gas flowing through the pipeline is determined by adjusting the pipeline gas flowrate as measured by the pipeline gas flowmeter by the volumetric correction ratio. The temperature of the sample gas (12) should be substantially the same as the pipeline gas in the pipeline when the sample gas flowrate is measured.

A flowmeter has an elongated housing with a fluid inlet, a fluid outlet and an axial passage therebetween. The fluid passage contains a flow splitter section and is connected to a flow sensor assembly. The flow splitter section is formed by a surface defining a longitudinal fluid path and a flow splitter secured in the fluid path, so as to form an annular gap between the surface of the fluid path and the flow splitter.

The surface of the fluid path defines a tapered calibration bore. The flow splitter has a tapered calibration section comprising the upstream portion of the flow splitter and at least one tapered expansion section comprising the downstream portion of the flow splitter. The taper of the calibration section being substantially parallel to the taper of the calibration bore, and the taper of the expansion section diverges away from the taper of the calibration score.

In some embodiments, the surface of the fluid path defines a cylindrical bore located upstream of the calibration bore and the flow splitter has a cylindrical section located upstream of calibration section. In these embodiments, the flow splitter is adjustably secured in the fluid path between the cylindrical section and cylindrical bore. The flow splitter section provides fluid flows possessing excellent linearity over a wide range of flow rates, while minimizing the danger of contamination.

A condition responsive apparatus is provided with a sensor channel (20) that is interconnected to a capillary tube restriction (41) which can be readily interchanged on the device to change the response of a condition responsive sensor (30). A very small sensor (30) is placed in the sensor channel (20). The sensor channel (20) and the capillary tube (41) can be placed generally parallel to one another to reduce the overall length of the apparatus.

A flow sensor assembly includes a housing (12) that defines an inlet port (16), an outlet port (18), a main channel (22) and a bypass channel (28). An inlet flow channel (34) fluidly connects the inlet port (16) of the flow sensor assembly to the main channel (22) and an outlet flow channel (40) fluidly connects the main channel (22) to the outlet port (18). A bypass feeder input channel (46) fluidly connects the main channel (22) to the bypass channel (28) and a bypass feeder output channel (52) fluidly connects the bypass channel (28) to the main channel (22). In some instances, at least 40 percent of an input pressure differential applied between the inlet port and the outlet port of the flow sensor assembly drops across the inlet flow channel and the outlet flow channel collectively. A sensor (10) is exposed to a fluid in the bypass channel (28) and senses a measure related to a flow rate of the fluid flowing through the bypass channel. The housing (12) may be configured to accommodate a relatively high pressure drop between the inlet port (16) and the outlet port (18), while still providing a good flow measurement with relatively low noise, having laminar flow in the bypass channel, and a relatively small mounting footprint.

A flow sensor assembly includes a housing (12) that defines an inlet port (16), an outlet port (18), a main channel (22) and a bypass channel (28). An inlet flow channel (34) fluidly connects the inlet port (16) of the flow sensor assembly to the main channel (22) and an outlet flow channel (40) fluidly connects the main channel (22) to the outlet port (18). A bypass feeder input channel (46) fluidly connects the main channel (22) to the bypass channel (28) and a bypass feeder output channel (52) fluidly connects the bypass channel (28) to the main channel (22). In some instances, at least 40 percent of an input pressure differential applied between the inlet port and the outlet port of the flow sensor assembly drops across the inlet flow channel and the outlet flow channel collectively. A sensor (10) is exposed to a fluid in the bypass channel (28) and senses a measure related to a flow rate of the fluid flowing through the bypass channel. The housing (12) may be configured to accommodate a relatively high pressure drop between the inlet port (16) and the outlet port (18), while still providing a good flow measurement with relatively low noise, having laminar flow in the bypass channel, and a relatively small mounting footprint.

Die Erfindung betrifft eine Messvorrichtung mit einem Drucksensor, wobei der Drucksensor eine Messzelle (1) aufweist, die dazu ausgebildet ist, einen Druck zu erfassen. Es ist vorgesehen, dass die Messzelle (1) des Drucksensors in einer oder angrenzend an eine Schutzzelle (2, 2') angeordnet ist, die mit einem Messfluid (7) gefüllt ist, das über mindestens eine Trennmembran (3, 31, 32) mit einem zu messenden Fluid (8) koppelbar ist. Des Weiteren ist vorgesehen, dass in der Schutzzelle (2, 2') zwischen der Trennmembran (3, 31, 32) und der Messzelle (1) eine Dämpfungseinrichtung angeordnet ist, die eine Verengungsstruktur (4) und ein dahinter angeordnetes Volumenerweiterungsmittel (5) umfasst, das bei einer Druckerhöhung im Messfluid (7) ein vergrößertes Volumen zwischen der Verengungsstruktur (1) und der Messzelle (1) bereitstellt.

A method an apparatus for measuring a base condition volumetric flowrate of a pipeline gas flowing through a pipeline in which a pipeline gas flowrate is measured by a pipeline gas flowmeter; a volumetric correction ratio is derived by: measuring a sample gas flowrate of sample gas (12) tapped from the pipeline, measuring an energy flowrate of the sample gas (12), measuring a heating value of the sample gas (12), and measuring a base condition density of the sample gas (12); and the base condition volumetric flowrate of the pipeline gas flowing through the pipeline is determined by adjusting the pipeline gas flowrate as measured by the pipeline gas flowmeter by the volumetric correction ratio. The temperature of the sample gas (12) should be substantially the same as the pipeline gas in the pipeline when the sample gas flowrate is measured.

A method and apparatus for measuring a base condition volumetric flowrate of a pipeline gas (14) flowing through a pipeline (16) in which a pipeline gas flowrate is measured by a pipeline gas flowmeter (22) that responds to density in a characteristic manner, a sample gas flowrate is measured by a sample gas flowmeter (10) that responds to density in the same manner as a pipeline gas flowmeter (22), and a base condition sample gas volumetric flowrate is measured by measuring the base condition energy flowrate of the sample gas (12), measuring the base condition heating value of the sample gas and dividing the base condition energy flowrate by the base condition heating value. The measured pipeline gas flowrate through the pipeline (16) is then adjusted by the ratio of the base condition sample gas flowrate divided by the measured flowrate of the sample gas (12). The temperature of the sample gas (12) should be substantially the same as the pipeline gas (14) in the pipeline when the sample gas flowrate is measured.