Badger Meter AHS - Hot Tap, Steam (2 to 24")" - Manual (Page 3)

INTRODUCTION
The Preso patented elliptical design outperforms and provides greater
accuracy than traditional differential pressure flow measurement devices . This
differential pressure flow meter is designed with a series of ports facing the
upstream velocity pressures, as well as flow sensing ports strategically located
ahead of the trailing edge flow separation .
The multi-ported, self-averaging flow element consists of an elliptical shape
with two independent flow sensing chambers . The impact velocity sensing
holes (high pressure) are located along the leading edge and the true static
sensing holes (low pressure) are on the exterior probe side . Model AHS comes
with instrument shutoff valves with provisions to accept a transmitter or direct
indicating meter .
True static
sensing holes
Impact velocity
sensing holes
Figure 1: AHS Ellipse pressure sensing holes
SPECIFICATIONS
Applications Saturated and super heated steam
Pipe Sizes AHS; 2…14 inches (50…356 mm)
AHS1; 14…24 inches (356…610 mm)
Pressure 800 psi (5515 kPa) maximum
Consult factory for higher pressures
Temperature 800° F (426° C) maximum
Consult factory for higher temperatures
Accuracy ±0 .75% of reading
Turndown Ratio 17:1 with no vacuum effect
Standard Components T-type head, 316 SS 1/2" FNPT connection
CS 3000 lb weld fitting, ASTM A105
316/316L SS Ellipse sensor
Instrument valves (2 per sensor), 1/2", CS
316 SS ID tag with wire
CS packing chamber with EPDM packing gland
CS isolation gate valve, NPT threaded
CS threaded nuts and bolts
CS nipples, schedule 40
Reynolds Number Greater than 75,000 maintains most accurate flow measurements
Less than 75,000 consult factory for estimated results
Resonance Less than 0 .8 but greater than 1 .2 . If greater than 0 .8, use double support . System shutdown
is required when the double support option is used . Select larger diameter Ellipse to avoid
double support .
Table 1: Specifications
User Manual
Page 3 April 2014