气体流量计选型指南

( ) ( ) QSCFM = 50ACFM x 14.7 + 50PSIG x
530
= 228.8
14.7
460 + 50°F
3. Calculate the sizing formula (see step 3)
F = 228.8 S
x
0.48
x
0.98
x
1.175
= 126.5
4. Select the flow meter body and page from table 4 (see step 4)
UNIVERSAL ®
FLOW MONITORS
Air and Gas Flow Meter Selection Guide
Universal Flow Monitors Inc. has thousands of flow meters in service which monitor air and gas systems in industries as diverse as automotive, steel, metal fabrication, paper processing, and rubber and tire manufacturing among others. This section of the catalog will help you to choose a flow meter for air and gas.
Fs = 126.5 indicating the M series, found on page AG8, will be required to meet your needs. Page
100 shows corresponding model number in example.
Definitions for above formulas:
Example by corresponding steps
SIZING PROCEDURE
Step 2. Is the gas flow expressed in SCFM, SCFH, SLPM or SCMH? If so proceed to step 3. If not, use one of the following formulas to convert.
1, 10, 100, 1,000, etc. 20, 200, 2,000, etc. 25, 250, etc. 30, 300, etc.
4, 40, 400, etc. 5, 50, etc. 6, 60, etc. 7, 8, 9, etc.
Example: If your maximum flow is 42 ACFM, a maximum scale reading of 50 ACFM is suggested.
92
TABLE 1 PRESSURE CORRECTION FACTOR
XP =
14.7
=
14.7 + PSIG
101.3 PkPa ABSOLUTE
OPERATING
PRESSURE
PSIG
kPa
5
34
10
69
15
103
20
138
25
172
30
207
35
241
40
276
45
310
50
345
55
379
91
Sizing lines
91 91
Air and Gas Flow Meter Selection Guide
To select the proper model code, we must convert the maximum reading of the gas flow to a sizing factor Fs (pages 92 and 93 will assist you). This is accomplished by multiplying this maximum flow by the conversion factors shown in tables 1, 2, and 3. This maximum flow must first be expressed in Standard Cubic Feet per Minute (SCFM) or Standard Cubic Feet per Hour (SCFH) or Standard Liters per Minute (SLPM) or Standard Cubic Meters per Hour (SCMH). If you would like Universal to select the proper code for you, see the Application Specification Guide, page 12.
x
294 273 + Tc
Select the proper housing for 42 ACFM flow of Argon at 50° F and 50 PSIG pressure.
1. Round up 42 to 50 ACFM (see step 1) 2. Convert to SCFM (see step 2)
See the tables shown on AG-3 for factors:
X = Table 1, X = Table 2, X = Table 3 (see page 93)
P
T
SG
Step 4. Use the sizing formula to select the correct housing size from table 4. (see page 93)
QACMH = Flow at actual conditions in Cubic Meters per Hour
Q
= Flow at actual conditions
ALPM
in Liters per Minute
PKPA ABS = Pressure in kPa absolute TC = Temperature in degrees Celsius
If your flow range falls on the blue sizing lines, use sizing formulas on pages 92 and 93.
All flow meters in this section are calibrated for one specific pressure, should pressure vary, consult factory.
This simplified sizing chart will help you locate which housing size will meet your requirements for air or nitrogen units. Find your line pressure in PSIG on the bottom of chart. Read up to your maximum air flow in SCFM. Where this point lies tells you which housing size you need. Use the following pages to build an ordering code number.
Step 3. Calculate the sizing formula FS as follows:
FS = or
QSCFM x XP x XT x XSG
or FS =
QSCMH x .5886 x XP x XT x XSG
F= or S
Q SLPM
x .0353 x
X P
x
X T
x
X SG
Biblioteka Baidu
FS = QSCFH x .0167 x XP x XT x XSG
To convert ACFH to SCFH
QSCFH =Flow in Standard Cubic Feet per Hour
( ) ( ) Q = Q
SCFH
ACFH
x
14.7 + PPSIG 14.7
x
530 460 +T
F
(OR) To convert ACFM to SCFM
QSCFM = Flow in Standard Cubic Feet per Minute
AIR FLOW IN STANDARD CUBIC FEET PER MINUTE (SCFM)
3900 3300 2700 2400 2100 1800
1500
1100 900 700 600 500 400
300
100 80 60 50 40 30
20
'L' Housing
(Page 102)
Typical applications include: • Measurement of air compressor output • Monitoring of nitrogen to controlled
atmosphere furnaces • Plant air consumption surveys • Disclosure of piping system leaks • Verification of air tool usage • Purging/blanketing systems • Verification of furnace gas supply
( ) ( ) QSCFM = QACFM x
14.7 + PPSIG 14.7
x
530 460 +T
F
Definitions for above formulas:
QACFH = Flow at actual conditions in Cubic Feet per Hour
QACFM = Flow at actual conditions in Cubic Feet per Minute
'M' Housing (Page 100)
'S' Housing (Page 98)
10 0
10 20 30 40 50 60 70 80 90 100 110 120 125 AIR PRESSURE IN POUNDS PER SQUARE INCH, GAUGE (PSIG)
For flow ranges less than 10 SCFM, use formulas on pages 92 and 93.
60
414
65
448
70
483
75
517
80
552
85
586
90
621
95
655
100
690
120
827
140
965
160
1103
180
1241
200
1379
250
1724
300
2069
350
2413
400
2758
450
3103
500
3448
Factors XP
0.86 0.77 0.70 0.65 0.61 0.57 0.54 0.52 0.50 0.48 0.46 0.44 0.43 0.42 0.40 0.39 0.38 0.37 0.37 0.36 0.33 0.31 0.29 0.27 0.26 0.24 0.22 0.20 0.19 0.18 0.17
SCMH
( ) ( ) P
Q SCMH
=
Q ACMH
x
KPA ABS x
101.3
294 273 + Tc
(OR) To convert ALPM to SLPM
or QSLPM = Flow in Standard Liters per Minute
( ) ( ) QSLPM = QALPM x
P KPA ABS 101.3
P
= Gas pressure (immediately downstream
PSIG
of the meter) in PSIG
TF
= Gas temperature in degrees Fahrenheit
To convert ACMH to SCMH
Q = Flow in Standard Cubic Meters per Hour
SIZING PROCEDURE
Step 1. Round up your maximum number so that the maximum scale reading and increments are sensible. The numbers below and their multiples of 10 are acceptable scale maximums: