Emerson 310A Data Sheet

Bulletin 71.2:310A

January 2009

Type 310A-32A Pressure Reducing Regulator and
Type 310A-32A-32A Working Monitor Regulator

Introduction

The Type 310A pilot-operated high-pressure regulator
(Figure 1) is used where high capacity and accurate
control are essential. This regulator includes one
Type 32A pilot assembly mounted on the main valve
for pressure reducing or wide-open monitoring
applications, or two Type 32A pilots mounted on the
main valve for working monitor applications.

Features

•  Accurate Control—Molded pilot diaphragms
provide a narrow proportional band and
registration of outlet pressure on the main
diaphragm allows excellent control sensitivity.

  •  Tight Shutoff—Throttling-sleeve design with

     Polytetrauoroethylene (PTFE) seat in the body  

ensures positive shutoff.

•  High Capacity—Straight-through ow passage
allows exceptionally high capacities and
stable operation.

•  Reduced Relief Requirements—Optional restricted
trim helps reduce relief valve size requirements; the
regulator is easily converted to full capacity by

     changing the trim, if ow conditions increase. 

•  Fast Speed of Response—Designed to meet
stringent speed of response requirements for
turbine startup and fuel gas applications.

W6278

Figure 1. Type 310A Regulator with Type 32A Pilot

•  Minimum Installation Space Required—Since
main valve design incorporates actuator spring,
less installation space is needed for the Type 310A
than for other regulators of comparable capacity.

www.emersonprocess.com/regulators

D102066X012

Bulletin 71.2:310A

Specications

Available Congurations 

Type 310A-32A: Type 310A main valve with one
Type 32A pilot for standard pressure-reducing and
wide-open monitoring applications
Type 310A-32A-32A: Type 310A main valve with
two Type 32A pilots for working monitor applications

Body Sizes and End Connection Styles 

1-inch body with NPT ends; and 1, 2, 3, 4, or
4 x 6-inch (DN 25, 50, 80, 100, and
100 x 150) body with CL300 RF or

       CL600 RF anged ends

Maximum Inlet and Pilot Supply Pressures

(1)

NPT and CL600 RF: 1500 psig (103 bar)
CL300 RF: 750 psig (51,7 bar)

Maximum Pressure Drop

(1)

NPT and CL600 RF: 1425 psig (98,3 bar)
CL300 RF: 720 psig (49,6 bar)

Maximum Outlet Pressure

Operating: 700 psig (48,3 bar)

(1)

To Avoid Internal Part Damage: 800 psig (55,2 bar)

  Exceeding this pressure may result in gas venting   

from pilot spring case.
Emergency (Casing): 1500 psig (103 bar) or
maximum inlet pressure whichever is lower.

Outlet Pressure Ranges and Proportional Bands

See Table 1

Maximum Travel

See Table 3

Minimum Differential Pressure

(1)

15 psig (1,0 bar)

Flow Coefcients

See Tables 4, 5, and 6

IEC Sizing Coefcients 

See Table 7

Flow Capacities 

See Tables 8, 9, 10, 11, and 12

Maximum Temperature Capabilities

(1)

Nitrile (NBR) with Wiper Ring:

-20° to 150°F (-29° to 66°C)
Fluorocarbon (FKM) with Wiper Ring:
0° to 150°F (-18° to 66°C)
Fluorocarbon (FKM) without Wiper Ring:
0° to 300°F (-18° to 149°C)

External Pilot Supply Connection 

1/4-inch NPT

Pilot Vent Connection 

1/4-inch NPT

Pressure Connections 

See Figure 9

Options

  •  Main valve body without pilot for on-off service 

  •  Remote-mounted pilot 

  •  Electrically controlled pilot using Type 662 Kixcel™ 

  •  Travel indicator 

  •  Pressure loaded pilot 

  •  Type 252 pilot supply filter 

  •  Backpressure protection system 

  •  Restricted Trim (30%, 50%, or 70%) 

  •  NACE construction 

  •  Inlet tap

Approximate Weights 

1-inch (DN 25): 45 pounds (20 kg)
2-inch (DN 50): 90 pounds (41 kg)
3-inch (DN 80): 145 pounds (66 kg)
4-inch (DN 100): 190 pounds (86 kg)
4 x 6-inch (DN 100 x 150): 235 pounds (107 kg)

Construction Materials 

Main Valve
Body: WCC steel

Throttling Sleeve: Stainless steel
Seat: PTFE 
Diaphragm Plates: Steel
Diaphragm and O-rings: Nitrile (NBR) (standard)

  or Fluorocarbon (FKM) 

Main Spring: Steel
Valve Plug: Stainless steel
Travel Indicator Rod: Stainless steel
Wiper Ring: Nitrile (NBR)

Pilot
Spring Case, Diaphragm Spacer, Pilot Body, and
Spring Case Cap: Cast steel
Adjusting Screw and Diaphragm Plate: Plated steel
Diaphragm: Nitrile (NBR) (standard) or

  Fluorocarbon (FKM) 

Orifice Assembly and Yoke: Stainless steel
Valve Disk Assembly: Stainless steel/Nitrile (NBR)
(standard) or Stainless steel/Fluorocarbon (FKM)   
Bleed Valve and Orifice: Stainless steel
Piston and Piston Seat Assembly: Stainless steel
and Nylon (PA)
Pilot Main Spring: Plated steel

1. The pressure/temperature limits in this bulletin or any applicable standard limitation should not be exceeded.

2

BLEED VALVE

FIXED 
RESTRICTION

BOTTOM

DIAPHRAGM

PILOT DIAPHRAGM PLATE 
AND YOKE ASSEMBLY

RELAY SEAT

TOP DIAPHRAGM

MAIN VALVE DIAPHRAGM

THROTTLING SLEEVE

Bulletin 71.2:310A

PILOT CONTROL
SPRING

E0696

INLET PRESSURE

OUTLET PRESSURE

ATMOSPHERIC PRESSURE

LOADING PRESSURE

PILOT SUPPLY PRESSURE

Figure 2. Type 310A-32A Regulator Operational Schematic

MAIN VALVE SPRING

Principle of Operation

Single-Pilot Regulator (Figure 2)

The regulator inlet pressure enters the pilot through
the external pilot supply line and is utilized as the
supply pressure for the pilot. The setting of the
pilot control spring determines the reduced outlet
(downstream) pressure.

In operation, assume the outlet pressure is less than 

the setting of the pilot control spring. Pilot control
spring force then overcomes the force resulting from
outlet pressure acting on the bottom diaphragm.
The spring pushes the diaphragm plate and yoke
assembly away from the relay seat, opening it and
supplying additional loading pressure to the main
valve diaphragm. When this additional loading
pressure exceeds the force resulting from outlet
pressure acting on the main valve diaphragm plus

STATIONARY 
VALVE PLUG

the force of the main valve spring, the diaphragm is
pushed away from the stationary valve plug. The
throttling sleeve opens wider, and the required gas is
supplied to the downstream system.

When gas demand in the downstream system has

been satisfied, the outlet pressure tends to increase.  

The increased outlet pressure acting on the bottom
diaphragm of the diaphragm plate and yoke assembly
results in a force that overcomes the pilot spring
setting and forces the assembly toward the relay
seat, closing it. The loading pressure acting on the
main valve diaphragm bleeds to the downstream

system through the fixed restriction in the diaphragm 

plate and yoke assembly. When rapid main valve
closure is required by unusual control conditions,
the bleed valve opens for increased bleed rate. The
force of increased outlet pressure acting on the main
valve diaphragm plus the main valve spring force
overcomes the force of decreased loading pressure
acting on the main valve diaphragm and moves the

3

Bulletin 71.2:310A

E0694

Figure 3. Typical Wide-Open Monitor Figure 4. Typical Working Monitor

throttling sleeve toward the stationary valve plug to

decrease the gas ow to the downstream system.

The top diaphragm in the pilot acts as a sealing
member for the loading chamber and as a balancing
member to the bottom diaphragm. The two
diaphragms are connected by a yoke. Pressure
change to the center chamber has little effect on the
positioning of the valve disk.

Monitor Systems

Wide-Open Monitors (Figure 3)

Monitoring regulators serve as overpressure protection
devices to limit system pressure in the event of failure
of working regulators feeding the system. The control
line of a wide-open monitoring regulator may be
connected downstream of the working regulator, so
that during normal operation the wide-open monitoring
regulator is standing wide open with the pressure
reduction being taken across the working regulator.
Only in case of working regulator failure does the
wide-open monitoring regulator operate.

E0695

of the Type 32A monitoring pilot. A plug in both the
working and monitoring pilots makes the internal
bleed nonfunctional. A restriction placed in the
external tubing between the diaphragm loading
pressure and the intermediate pressure acts as a
downstream bleed.

If the second-stage working regulator fails to open, 

the distribution pressure increases to the setting of
the Type 32A monitoring pilot (slightly higher than
the original distribution pressure) and is controlled
at that level by the Type 310A-32A-32A. Thus,
downstream equipment is protected against a major
overpressure condition without disrupting service or
venting gas to atmosphere.

In the working pilot, the inlet pressure is reduced 

to a pre-determined pilot supply pressure, which is
further reduced to loading pressure for the Type 310A
diaphragm. The loading pressure is piped through
the portion of the monitoring pilot blocked open by the
spacer and, as long as distribution pressure is below
the setting of the monitoring pilot, passes through the

relay orifice of the monitoring pilot to the diaphragm 

case of the Type 310A body.

Working Monitors (Figures 4 and 5)

The Type 310A-32A-32A working monitor regulator
differs from wide-open monitors in that it has working
monitor capability. This means that it normally
reduces pressure and throttles while the second-stage
regulator is in operation. Should the second-stage
working regulator fail open, the Type 310A-32A-32A
will take over the entire pressure reduction function.

The working monitor pilots are adaptations of two
Type 32A pilots with special internal parts, due to
the pressure conditions in this piloting system. A
spacer blocks open the differential regulator portion

4

Distribution pressure is piped back to the monitoring
pilot. As long as the distribution pressure is less than
the monitoring pilot setting, the working pilot controls

the Type 310A to maintain intermediate pressure.  If 

the distribution pressure increases to the monitoring

pilot setting, the monitoring pilot relay orifice starts 

to throttle the loading pressure to the Type 310A
diaphragm. This allows the Type 310A main spring
to move the throttling sleeve closer to the seat and
control distribution pressure at the monitoring pilot set
point. Therefore, failure of the second-stage working
regulator is controlled with only a slight increase in
distribution pressure, with the Type 310A-32A-32A
accomplishing the entire pressure reduction function.

PLUG

SPACER

Bulletin 71.2:310A

WORKING PILOT

RESTRICTION

E0693

INLET PRESSURE

OUTLET PRESSURE

ATMOSPHERIC PRESSURE

LOADING PRESSURE

INTERMEDIATE PRESSURE

PILOT SUPPLY PRESSURE

PLUG

MONITORING PILOT

Figure 5. Type 310A-32A-32A Working Monitor Regulator Operational Schematic

Table 1. Outlet Pressure Ranges

OUTLET PRESSURE RANGE, PSIG (bar) PROPORTIONAL BAND, PSIG (bar) SPRING COLOR SPRING PART NUMBER

10 to 20 (0,69 to 1,4) 0.5 (0,03) Silver 1D809627022

10 to 100 (0,69 to 6,9) 2 (0,14) Yellow 1E392527022

100 to 250 (6,9 to 17,2) 5 (0,34) Blue 1D387227022

250 to 600 (17,2 to 41,4) 12 (0,83) Red 1D465127142

400 to 700 (27,6 to 48,3)

(1)

20 (1,4) Green 13A5543X012

1. Available with Nitrile (NBR) pilot diaphragm only.

Table 2. Recommended Minimum Differential Between Monitoring Pilot Setting and Distribution Pressure

OUTLET PRESSURE RANGE, PSIG (bar) SPRING COLOR

10 to 20 (0,69 to 1,4) Silver 1D809627022 3.0 (0,21) over normal distribution pressure

10 to 100 (0,69 to 6,9) Yellow 1E392527022 5.0 (0,34) over normal distribution pressure

100 to 250 (6,9 to 17,2) Blue 1D387227022 10 (0,69) over normal distribution pressure

250 to 600 (17,2 to 41,4) Red 1D465127142 15 (1,0) over normal distribution pressure

400 to 700 (27,6 to 48,3) Green 13A5543X012 20 (1,4) over normal distribution pressure

SPRING

PART NUMBER

MINIMUM PRESSURE AT WHICH

MONITORING PILOT CAN BE SET, PSIG (bar)

5