Data Sheet

Bulletin 71.1:CS800
16
Non-Relieving “N”
Type numbers with the “N” sufx, e.g., Type CS800IN,
do not provide internal relief discharge through the
diaphragm assembly.
The CS800 Series regulators have outlet pressure
ratings that are lower than their inlet pressure ratings.
A pressure relieving or pressure limiting device is
needed if the application inlet pressure can exceed
the outlet pressure rating and the regulator is not
equipped with internal relief, high capacity relief,
Integral True-Monitor™ Protection or Secondary
Seat™ Protection.
Note
Overpressuring any portion of a
regulator or associated equipment
may cause personal injury, leakage or
property damage due to bursting of
pressure-containing parts or explosion
of accumulated gas. Provide appropriate
pressure relieving or pressure limiting
devices to ensure that the limits in the
specications section are not exceeded.
Regulator operation within ratings does
not prevent the possibility of damage
from external sources or from debris in
the pipeline.
Downstream Control Line Connection
A CS800 Series regulator with an EN, ET or ER in
the type number has a blocked throat, an O-ring
stem seal and a 3/4 NPT control line tapping in the
lower diaphragm casing, see Figure 4. A regulator
with a downstream control line is used for monitoring
installations or other applications where there is
other equipment installed between the regulator and
the pressure control point. The O-ring stem seal
helps separate body pressure from diaphragm case
pressure on monitor installations where leakage
cannot be tolerated.
Capacity Information
Tables 14 through 66 provide natural gas regulating
capacities at selected inlet pressures, outlet pressure
settings and body outlet sizes. Flows are in SCfh
(60°F and 14.7 psia) and Nm
3
/h (0°C and 1.01325 bar)
of 0.6 specic gravity natural gas. To determine
equivalent capacities for air, propane, butane or
nitrogen, multiply the capacity number in the tables by
the following appropriate conversion factor: 0.775 for
air, 0.628 for propane, 0.548 for butane or 0.789 for
nitrogen. For gases of other specic gravities, multiply
the given capacity by 0.775 and divide by the square
root of the appropriate specic gravity.
Relief Sizing
For critical ow:
To determine wide-open ow capacities for relief
sizing of 0.6 specic gravity natural gas at 60°F at
critical pressure drops (absolute outlet pressure equal
to approximately one-half or less than one-half of the
absolute inlet pressure), use the following formula:
Q=P
1abs
(C
g
)(1.29)
For subcritical ow:
If pressure drops are lower than critical (absolute
outlet pressure greater than approximately one-half
the absolute inlet pressure), use the following formula
and convert according to the factors in the preceding
paragraph if necessary:
Q
= C
g
P
1
SIN
520
GT
3417
C
1
∆P
P
1
DEG
where:
C
1
= C
g
/C
v
(see Table 3)
C
g
= Gas sizing coefcient (see Table 3)
G = Gas specic gravity (air = 1.0)
P
1
= Regulator inlet pressure, psia
∆P = Pressure drop across regulator, psig
Q = Gas ow rate, SCfh
T = Absolute temperature of gas at inlet, °Rankine
Note
Due to boost, the above formulas
cannot be used to obtain correct
regulating capacities for regulators with
internal registration.
The published capacities were obtained using inlet and
outlet piping the same size as the regulator body size.