Meriam Laminar Flow Elements User Manual
Page 14
14
Table A-32422
A i r T e m p e r a t u r e / V i s c o s i t y C o r r e c t i o n F a c t o r s f o r S C F M A i r B a s e
T e m p e r a t u r e 7 0 °F 181.7 Micropoise Reference NBS Circular 564
Correction Factor =
ૢ.ૠ
ૢ.ૠା °ࡲ
x
ૡ.ૠ
ஜ∗
µair = 14.58 x
ቀ
ૢ.ૠା °۴
.ૡ
ቁ
110.4 +
ቀ
ૢ.ૠା °۴
.ૡ
ቁ
Temp
°F
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
50
60
70
80
90
100
110
120
130
140
150
1.0707
1.0344
1.0000
.9674
.9365
.9072
.8793
.8528
.8276
.8036
.7807
1.0670
1.0308
.9966
.9642
.9335
.9043
.8766
.8503
.8252
.8013
.7785
1.0633
1.0273
.9933
.9611
.9305
.9015
.8739
.8477
.8227
.7990
.7763
1.0596
1.0238
.9900
.9579
.9275
.8987
.8712
.8452
.8203
.7966
.7741
1.0559
1.0204
.9867
.9548
.9246
.8959
.8686
.8426
.8179
.7943
.7719
1.0523
1.0169
.9834
.9517
.9216
.8931
.8659
.8401
.8155
.7920
.7697
1.0487
1.0135
.9802
.9486
.9187
.8903
.8633
.8376
.8131
.7898
.7675
1.0451
1.0101
.9770
.9456
.9158
.8875
.8606
.8351
.8107
.7875
.7653
1.0415
1.0067
.9737
.9425
.9129
.8848
.8580
.8326
.8083
.7852
.7632
1.0379
1.0033
.9705
.9395
.9100
.8820
.8554
.8301
.8060
.7830
.7610
* When flowing gas other than air, use the viscosity in micropoise of the gas at flowing temperature in
the Correction Factor equation.
Table A-35700
Temperature Correction Factor
Base Temperature = 70°F
Tcf =
ૢ.ૠ
(ૢ.ૠା °۴)
Maintenance
Accumulation of dirt in the capillaries of the laminar element will affect the accuracy. When in
doubt, hold the laminar in front of a high intensity light, sighting through the capillaries. Any dirt
will be apparent. Loose dirt can be blown out with shop air (no more than 100 PSI) in reverse direction
of flow. Shop air must be clean and dry. Brushing or rubbing the ends of the matrix element is not
recommended because the matrix can be deformed, altering the calibration. Unless the customer has the
facilities and primary standards to check calibration after cleaning, we recommend returning the unit to
Meriam for cleaning and calibration.