Specifications
The Specifications section lists the specifications for the Type CT88 backpressure regulators. Factory specification is
stamped on the nameplate fastened on the backpressure regulator at the factory.
Body Sizes
NPS 2, 3 and 4 / DN 50, 80 and 100
End Connection
CL150 RF
Maximum Working Pressure
(1)(4)
Based on CL150 RF Flange Pressure Rating,
See Table 1
Backpressure Control Ranges
(1)(2)
NPS 2 / DN 50:
10 to 145 psi / 0.7 to 10 bar
NPS 3 and 4 / DN 80 and 100:
15 to 145 psi /
1.0 to 10 bar
Wide-Open Flow Coefficients C
v
NPS 2 / DN 50–C
v
:
59
NPS 3 / DN 80–C
v
:
148
NPS 4 / DN 100–C
v
:
240
Flow Characteristic
Quick Open
Shutoff Classification
ANSI Class VI
Temperature Capabilities
(1)(3)
Fluorocarbon (FKM)
(5)
:
20 to 248°F / -7 to 120°C
(6)
Construction Materials
Body:
Carbon steel (WCB)
Diaphragm and Seals:
Fluorocarbon (FKM)
Trim Parts:
316 Stainless steel
Control Line Connection Size
1/4 NPT
Approximate Weights
NPS 2 / DN 50:
89 lbs / 40 kg
NPS 3 / DN 80:
131 lbs / 60 kg
NPS 4 / DN 100:
184 lbs / 84 kg
Table 1.
Pressure-Temperature Ratings for CL150 Carbon steel (WCB)
1. The pressure/temperature limits in this Instruction Manual and any applicable standard limitation should not be exceeded.
2. For lower set pressures, contact the factory.
3. It may be assumed that the material temperature is the same as the working fluid temperature.
4. Maximum inlet pressure depends on working temperature (Refer to ASME B16.42 or Table 1).
5. Fluorocarbon (FKM) is limited to 200°F / 93°C for hot water.
6. Increased working temperature may reduce the maximum inlet pressure range (Refer to ASME B16.42 or Table 1).
Principle of Operation
See Figure 2. Type CT88 direct-operated
backpressure regulator responds to changes in inlet
pressure. Inlet pressure is registered on the underside
of the diaphragm through an external sensing line that
is connected to the lower diaphragm casing.
As long as the inlet pressure remains below setpoint,
control spring keeps the disk against the seat ring
providing tight shutoff with no flow through the
backpressure regulator.
When inlet pressure rises above the set pressure,
pressure on the diaphragm overcomes the control
spring force. This causes the diaphragm to move
upward, lifting valve stem together with the valve plug
away from seat ring. The flow path through the valve
opens and excess pressure is vented. When upstream
pressure drops below setpoint, the valve closes.
TEMPERATURE
(1)
MAXIMUM WORKING PRESSURE
°F
psi
20 to 100
290
200
260
248
245
°C
bar
-7 to 38
20.0
50
17.0
100
17.9
120
16.9
1. For intermediate temperatures, linear interpolation is permitted.
2
Type CT88
