Data Sheet

Bulletin 71.4:LR128
9
Table 5. Type LR128 Main Valve Minimum Differential Pressure
(1)
MAIN VALVE
BODY SIZE
DIAPHRAGM
MINIMUM DIFFERENTIAL, PERCENT OF CAPACITY
For 90% Capacity For 100% Capacity
In. DN Diaphragm Code Diaphragm Material psid bar d psid bar d
1 25
17E68(standard) Nitrile (NBR), Low Minimum Differential 30 2.1 30 2.1
17E97 Nitrile(NBR),HighErosionResistance 35 2.5 35 2.5
17E88
Fluorocarbon (FKM),
High Temperature Capability
30 2.1 30 2.1
2 50
17E68(standard) Nitrile (NBR), Low Minimum Differential 18 1.2 19 1.3
17E97 Nitrile(NBR),HighErosionResistance 24 1.7 24 1.7
17E88
Fluorocarbon (FKM),
High Temperature Capability
18 1.2 19 1.3
3 80
17E68(standard) Nitrile (NBR), Low Minimum Differential 21 1.5 28 1.9
17E97 Nitrile(NBR),HighErosionResistance 23 1.6 23 1.6
17E88
Fluorocarbon (FKM),
High Temperature Capability
21 1.5 28 1.9
4 100
17E68(standard) Nitrile (NBR), Low Minimum Differential 16 1.1 30 2.1
17E97 Nitrile(NBR),HighErosionResistance 16 1.1 34 2.3
17E88
Fluorocarbon (FKM),
High Temperature Capability
16 1.1 30 2.1
1. See Table 1 for Type LR128 main valve structural design ratings and Table 2 for Type MR98H pilot rating.
Table 7. Flow and Sizing Coefcients for Type LR128 Main Valve at 100% Capacity
MAIN VALVE BODY SIZE
REGULATING
COEFFICIENTS
WIDE-OPEN
COEFFICIENTS
K
m
IEC SIZING COEFFICIENTS
In. DN C
v
C
1
C
v
C
1
X
T
F
D
F
L
1 25 14.8 33.4 15.2 33.5 0.88 0.706 0.06 0.94
2 50 50.8 37.2 52.4 37.2 0.92 0.875 0.09 0.96
3 80 91.4 38.8 94.1 38.8 0.94 0.952 0.09 0.97
4 100 147 38.7 151 38.7 0.85 0.947 0.09 0.92
Table 6. Type LR128 Maximum Pressure Ratings and Diaphragm Selection Information
(1)
BODY SIZE
DIAPHRAGM
MATERIAL
MAXIMUM
OPERATING
INLET
PRESSURE
(3)
MAXIMUM
OPERATING
DIFFERENTIAL
PRESSURE
(3)
MAXIMUM
EMERGENCY INLET
AND DIFFERENTIAL
PRESSURE
DIAPHRAGM
STYLE
In. DN psig bar psid bar d psid bar d
1 25
17E68Nitrile(NBR),Lowtemperature 450 31.0 400 27.6 450 31.0
130
17E97Nitrile(NBR),High-pressure
and/or erosion resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
17E88Fluorocarbon(FKM),Higharomatic
hydrocarbon content resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
2 50
17E68Nitrile(NBR),Lowtemperature 450 31.0 400 27.6 450 31.0
17E97Nitrile(NBR),High-pressure
and/or erosion resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
17E88Fluorocarbon(FKM),Higharomatic
hydrocarbon content resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
3 80
17E68Nitrile(NBR),Lowtemperature 360 24.8 300 20.7 450 31.0
17E97Nitrile(NBR),High-pressure
and/or erosion resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
17E88Fluorocarbon(FKM),Higharomatic
hydrocarbon content resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
4 100
17E68Nitrile(NBR),Lowtemperature 360 24.8 300 20.7 450 31.0
17E97Nitrile(NBR),High-pressure
and/or erosion resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
17E88Fluorocarbon(FKM),Higharomatic
hydrocarbon content resistance
450 31.0 450
(2)
31.0
(2)
450 31.0
1. See Table 1 for main valve structural design ratings and Table 3 for pilot ratings.
2. For differential pressure above 400 psid / 27.6 bar d diaphragm temperatures are limited to 150°F / 66°C.
3.Thesearerecommendationsthatprovidethebestregulatorperformanceforatypicalapplication.PleasecontactyourlocalSalesOfceforfurtherinformationifadeviationfromthe
standard recommendations are required.