BGN Metal Tube Variable Area Flowmeter
Quick Spec:
High pressure and temperature resistance
Suitable for steam tracing
Linear flow indicator and output signals
Short length of 250 mm enables versatile application in all industries
Four interchangeable standard indicator systems
The BGN range of metal tube variable area flowmeters has been designed for those applications where conventional glass tube instruments may not be used on account of high pressures or liquid opacity, or for safety considerations when metering hazardous chemicals.
As opposed to the 'fixed float diameter tapered tube' principle used in conventional variable area meters, the BGN utilises a fixed sharp edged orifice and tapered profiled float, the float profile being machined to exacting standards to ensure a linear scaling.
More Info
Operating pressures are largely limited only by the flange ratings, and elevated temperature operation is possible by extending the indicator coupling to remove the indicator and associated electrical or pneumatic transmitters from the source of heat.
Large scale production and exacting machining specifications enable all parts of the flowmeter to be
mechanically interchangeable within a specific range size, and range conversions and replacement of
indicators can be carried out by any skilled engineer without difficulty.
Electrical transmitting system, or high and low alarm contact devices may be fitted in minutes within the indicator housing.
Operating Principle
The measuring system comprises a sharp edged fixed orifice ring, and a tapered float.
When the fluid flows vertically upwards, the float rises until a point of equilibrium is reached where
the weight of the float is balanced by the buoyancy force 'A'.
This results in an annulus 'S' the area of which is directly proportional to the flowrate.
The vertical movement of the float is transmitted to an external indicator through a magnetic coupling system such that glands and seals are avoided.
Advantages
Simple robust and low maintenance all metal design
High pressure and temperature resistance
Suitable for steam tracing
Linear flow indicator and output signals
Short length of 250 mm enables versatile application in all industries
Four interchangeable standard indicator systems