Download presentation

Presentation is loading. Please wait.

Published byTessa Platts Modified about 1 year ago

1
1. Diaphragm Meters n Principles of Operation

2
1. Diaphragm Meters

3
n Residential Meters –AC-175 –AM-250 –AT-210/250 –AC-250 –AT-350 –AL-425

4
1. Diaphragm Meters

5
n B109.2 (Over 500 CFH) n Flow Rates for each Class (CFH) –ClassMinimumMaximum » » » » »

6
1. Diaphragm Meters n Commercial –AC-630 –AL-800 –AL-1000

7
1. Diaphragm Meters n Industrial –AL-1400 –AL-2300 –AL-5000

8
1. Diaphragm Meters

9
Capacity at Elevated Pressure Diaphragm meter capacities at elevated pressures must be de-rated to limit differential pressure to a maximum of 8” w.c. This practice of limiting differential pressure extends service life of valves and diaphragms.

10
1. Diaphragm Meters n Capacity of diaphragm meter at elevated pressure Q r = Q i x {( P g + P a ) / P b } 3/4

11
1. Diaphragm Meters n Q r = Q i x {( P g + P a ) / P b } 3/4 n Where: –Q r = Rated Capacity at elevated pressures –Q i = Rated Capacity at 0.25 psig –P g = Gage Pressure –P a = Atmospheric Pressure –P b = Base Pressure

12
1. Diaphragm Meters Capacity at Elevated Pressure Example: What is the capacity of an AL-1400 diaphragm meter rated at 3000 SCFH at a 2” w.c. differential pressure when it is operating at 15 PSIG, an atmospheric pressure of 14.4 PSIA, and a base pressure of 14.73?

13
1. Diaphragm Meters Capacity at Elevated Pressure Q r = Q i x {(P G +P a )/P b } 3/4 Q r = 3000 x {( )/14.73} 3/4 = 5000 SCFH

14
1. Diaphragm Meters

15
Size of diaphragm meter operating at elevated pressure needed for a load. Q i = Q r / {(P G +P a )/P b } 3/4 Where: Q i = Rated Capacity at 0.25 psig Q r = Load in SCFH P G = Gage Pressure P a = Atmospheric Pressure P b = Base Pressure

16
1. Diaphragm Meters Meter Sizing Based on Load Example: Connected load = 3,500 scfh Meter pressure = 15 psig Atmospheric pressure = 14.4 psia Base pressure = psia What size meter should be used?

17
1. Diaphragm Meter Meter Sizing Based on Load Solution Q i = Q r / {(P G +P a )/P b } 3/4 = 3500/{( )/14.73} 3/4 = 3500/ {1.9959} 3/4 = 3500/1.679 = 2084 CFH Use an AL-2300

18
1. Diaphragm Meter

19

20
n Options –Pressure Compensating Index

21
1. Diaphragm Meter n Options –Temperature Compensation

22
1. Diaphragm Meter n Options –AMR (Automatic Meter Reading) Compatible

23
1. Diaphragm Meters n Accuracy

24
1. Diaphragm Meters n Installation –Ship, store, and install in upright position –Keep dirt and water out –Level + 1/4” –No undue stress –Do not bury –Filter may be needed –Protect from damage –Hand tighten swivels first –Check for leaks –Slowly pressurize –Need for by-pass? –Cathodic Protection considerations

25
1. Diaphragm Meters n Factors that affect Accuracy –Internal friction that increases differential –Maintaining constant diaphragm displacement over a range of operating conditions –External leaks –Internal leaks –Wear

26

Similar presentations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google