Swagelok RA Series User manual

RA4/6/8 Pressure-Reducing Ratio Regulator
User Manual
Read the complete manual before installing and using the regulator.

2
Safe Product Selection
When selecting a product, the total system design must be considered to ensure safe, trouble-free
performance. Function, material compatibility, adequate ratings, proper installation, operation, and
maintenance are the responsibilities of the system designer and user.
WARNING
•Users must be trained and equipped for the handling, use, and servicing of pressure
products and systems.
•Users must contact their gas or liquid supplier for specific safety precautions and
instructions.
•Gaseous media should be free of excessive moisture to prevent icing at high flow.
•Always wear the appropriate protective clothing, including safety glasses, gloves, etc., if
required.
•Follow the applicable safety and maintenance procedures.
•Obey specific local regulations.
•Do not exceed the maximum inlet and outlet pressure rating of the product or its
accessories.
•Operate within the temperature limits and any other conditions specified for the product.
•Do not drop or damage the product in any other way. This may negatively affect the
performance of the product which can cause the product to malfunction.
•Venting fluids and gases can be dangerous. Vent to a safe environment away from people.
Ensure adequate ventilation.

3
Contents
Introduction........................................................................................................................................................ 4
Overview.......................................................................................................................................................... 4
Standard Features........................................................................................................................................... 4
Additional Options ........................................................................................................................................... 4
Oxygen Service............................................................................................................................................... 4
Installation.......................................................................................................................................................... 5
Points of Attention Before Installation ............................................................................................................. 5
Installation ....................................................................................................................................................... 5
Dome Pressure Control................................................................................................................................... 6
Operation............................................................................................................................................................ 8
Required Tools for Operation.......................................................................................................................... 8
Points of Attention Before Operation............................................................................................................... 8
Adjusting the Set Pressure.............................................................................................................................. 8
Maintenance....................................................................................................................................................... 9
Required Tools for Maintenance..................................................................................................................... 9
Points of Attention Before Removal from the System................................................................................... 10
Removal from the System............................................................................................................................. 10
Assembly Reference Data............................................................................................................................. 11
Disassembly.................................................................................................................................................. 14
Points of Attention Before Reassembly......................................................................................................... 14
Reassembly................................................................................................................................................... 15
Testing.............................................................................................................................................................. 16
Seat Leak Test .............................................................................................................................................. 16
Shell Leak Test.............................................................................................................................................. 16
Troubleshooting .............................................................................................................................................. 17

4
Introduction
Overview
- The RA series are pneumatic-loaded pressure-reducing ratio regulators designed for the regulation of
high pressure, gases and liquids.
- For pressure and temperature rating information refer to the Pressure Regulators, RHPS Series catalog,
MS-02-430. Note that seat seal material selection can limit the regulator operational pressure at elevated
temperatures.
WARNING
Check that system pressures and temperatures do not exceed those stated on the regulator as
this could result in product failure.
Standard Features
- Bolted construction
- Stainless steel as standard
- Fully serviceable
- Diaphragm controlled
- Piston sensing
- Balanced poppet
- Self-venting
Additional Options
The regulator is available with the following options:
Gauge connections
WARNING
The self-venting feature is for venting off excessive outlet pressure under zero flow conditions.
It is not intended to be used as a safety relief valve.
Oxygen Service
- For more information about hazards and risks of oxygen enriched systems see the Swagelok Oxygen
System Safety technical report (MS-06-13).
- Cleaning and packaging to ensure compliance with product cleanliness requirements stated in ASTM G93
Level C is available. Refer to the Pressure Regulators, RHPS Series, catalog, MS-02-430, for additional
information.

5
Installation
CAUTION
Do not use the regulator as a shutoff device. A level of leakage across the regulator seat can
occur during normal operation.
Points of Attention Before Installation
This regulator can be equipped with a variety of different options. Before installing the regulator you should
fully understand the functions of the supplied options and the suitability of your particular regulator for the
intended application.
- The preferred mounting position of the regulator is horizontal with the dome facing upwards per Fig 1.
Alternative mounting positions may increase the risk of component wear.
- It may be necessary to remove the regulator from the system during maintenance or service. Ensure that
this is possible.
- The regulator is suitable for gases and liquids. Ensure compatibility between the regulator’s materials of
construction and the system media.
- Swagelok recommends connecting a vent line to the self-vent port when the process media is hazardous
or toxic.
Installation
- Verify that the regulator, the connections, and its accessories are undamaged.
- Verify that the regulator and its accessories are suitable for the system operating pressure and
temperature and have suitable connections.
- At the time of delivery any gauge ports may be plugged with blind fittings. Remove these and connect
gauges if desired.
- If inlet/outlet fittings are being used, assemble them to the regulator, per the manufacturer’s instructions,
prior to installing the regulator in the system.
CAUTION
Ensure all upstream tubing/pipework is clean and free from debris. Any swarf, lint, wire, etc. may
damage the regulator, resulting in a seat leak.
- Verify the flow direction of the system and mount the regulator accordingly.
- Securely make the appropriate connections to the regulator in accordance with the procedures
recommended by the connection manufacturer.
- Ensure that the tubing/pipework and the regulator are adequately supported and that there is no stress on
the connections.
- Upstream and downstream shutoff valves should be installed in the system to facilitate servicing,
maintenance, and troubleshooting of the regulator.
CAUTION
Do not plug the vent port. Vented pressure would become trapped and could be released upon
disassembly. The port must be open to atmosphere either directly or via a vent line.

6
Dome Pressure Control
The dome pressure of the regulator controls the outlet pressure. There are several methods available for
supplying and controlling the dome pressure.
- External dome control. In this setup the dome pressure is supplied from an independent source, such as
a cylinder or main supply (Fig 1). The best performance will be achieved by allowing a small flow to
continuously pass through the pilot regulator.
- Electronic control. In this setup an electronic pilot regulator, fed from an independent source, is used in
conjunction with a pressure transducer to directly control the dome pressure (Fig 2).
NOTICE
The outlet pressure of the regulator is sensitive to changes in the dome pressure. Every change
to the dome pressure will result in an outlet pressure change equal to the dome pressure
change, multiplied by the ratio of the regulator. For example; with a 1:70 ratio regulator a rise of
14.5 psig (1 bar) of the dome pressure will result in a rise of 1015 psig (70 bar) of the outlet
pressure.
External Dome Control Schematic
Fig 1
Pilot regulator
0-145 psig
0-10 bar
(Shop air)
Ratio regulator
Cylinder or
mains supply

7
Electronic Control Schematic
Fig 2
Electronic
pilot regulator
4-20mA/0-10V
4-20mA/0-10V
Cylinder or
mains supply
Pressure
transducer
Ratio regulator

8
Operation
Required Tools for Operation
No tools are required for changing the set pressure on a standard regulator.
Points of Attention Before Operation
CAUTION
The product can be hot or cold, depending on the environmental temperature and the process
media temperature. Take the necessary precautions before operating or touching the product.
- Stopping flow through the regulator by closing a downstream shutoff valve may result in a rise in outlet
pressure above the set pressure. This is usually referred to as “lock-up”. This phenomenon does not
indicate a problem with the regulator.
- A decrease of the flow rate may result in a rise of the outlet pressure. An increase of the flow rate may
result in a fall of the outlet pressure. This is usually referred to as “droop”. This phenomenon does not
indicate a problem with the regulator.
- A decrease of the inlet pressure may result in a rise of the outlet pressure. An increase of the inlet
pressure may result in a fall of the outlet pressure. This is usually referred to as “inlet dependency” or
“Supply Pressure Effect (SPE)”. This phenomenon does not indicate a problem with the regulator.
Adjusting the Set Pressure
- The set pressure is the desired outlet pressure of the regulator.
- To set the regulator, ensure that the supply pressure is greater than the required set pressure but does
not exceed the maximum rating of the regulator.
- Excess outlet pressure will self vent through the port in the side of the regulator.
1. Ensure there is zero pressure in the dome.
2. Steadily open the supply valve to allow inlet pressure to the regulator.
3. The set pressure is controlled by altering the dome pressure. Increasing the dome pressure raises the set
pressure while decreasing the dome pressure lowers the set pressure.
NOTICE
The outlet pressure of the regulator is sensitive to changes in the dome pressure. Every change
to the dome pressure will result in an outlet pressure change equal to the dome pressure
change, multiplied by the ratio of the regulator. For example; with a 1:70 ratio regulator a rise of
14.5 psig (1 bar) of the dome pressure will result in a rise of 1015 psig (70 bar) of the outlet
pressure.
4. To obtain the most accurate set pressure, final adjustment must be made while increasing the set
pressure. If the desired outlet pressure is exceeded, reduce the pressure below this value then increase
up to it.
5. Fully open any downstream valve to allow full flow during operation.
6. Once under flow conditions make any final set pressure adjustments per steps 3 and 4 if required.

9
Maintenance
WARNING
Incorrect or improper repair or servicing of this product can cause serious personal injury and
property damage.
- All repairs, servicing, and testing of this product must be performed by competent personnel.
- Following any maintenance of the regulator, it is recommended that the product be tested for operation
and leakage.
- The product should be checked periodically for proper and safe operation. It is the user’s sole
responsibility to determine the frequency of maintenance based on the application.
- To reduce maintenance related system downtime to a minimum, either during commissioning or normal
operation, Swagelok recommends having maintenance kits readily available on site. The need for
maintenance kits is particularly important during the commissioning phase of a system installation due to
residual assembly debris remaining in the system. Such debris can cause a seat leak in the regulator,
resulting in components needing to be replaced.
Required Tools for Maintenance
Smooth-jawed vise
Calibrated torque wrench
up to 52 lbf·ft (70 N·m)
24 mm socket
Lubricant (included in kit)
WL-8①
Krytox® 240 AC②
10 mm open-
ended wrench
Liquid leak detector
5 mm hex drive
6 mm hex drive
①Standard cleaned assemblies
②ASTM G93 or SC11 cleaned assemblies Table 1

10
Points of Attention Before Removal from the System
- Swagelok recommends removing the regulator from the system for servicing and maintenance.
- Follow all local system safety and maintenance procedures when removing the regulator.
WARNING
Before removing a regulator from the system, to avoid personal injury, you must:
•Depressurize the system and dome.
•Purge the system to remove any residual system media left in the regulator.
•Always vent to a safe environment away from people and ensure there is adequate
ventilation.
CAUTION
Check if the process media is hazardous or toxic. If required, take the necessary safety
precautions to ensure a safe workspace and your personal safety.
CAUTION
The product can be hot or cold, depending on the environmental temperature and the process
media temperature. Take the necessary precautions before operating or touching the product.
Removal from the System
1. Isolate the regulator from all pressure sources by closing all appropriate upstream valves in the system.
2. With the pilot regulator set, open all appropriate downstream valves to allow pressure to vent from the
regulator.
WARNING
Ensure all pressure on the inlet, outlet and dome has been fully vented. The accidental release
of residual trapped pressure can cause serious personal injury.
3. Ensure that any external dome feed or vent line connection is disconnected.
4. Disconnect and remove the regulator from the system.

11
Assembly Reference Data
Item
Component Name
Kit Type(s)
Torque
lbf·ft (N·m)
Recommended Lubrication
(included in kit per Table 1)
1
Body plug
C1, C2
37 (50)
Lubricate threads
2
Body plug backup ring
B1, B2, C1, C2
3
Body plug O-ring
B1, B2, C1, C2
4
Poppet spring
C1, C5
5
Poppet backup ring
A1, B1, B2, C1
6
Poppet O-ring
A1, B1, B2, C1
Lubricate
7
Poppet
A1, B1, C1
8
Seat
A1, A2, B1, C1
9
Seat O-ring
A1, A2, B1, B2, C1
10
Body
N/A
11
Piston plate O-ring
B1, B2, C1, C3
12
Relief seat
A1, A2, B1, B2, C1
13
Piston
C1, C3
14
Piston O-ring
B1, B2, C1, C3
Lubricate
15
Piston backup ring
B1, B2, C1, C3
16
Nut
E1
17
Washer
E1
18
Piston plate
C1, C3
19
Washer
N/A
20
Cap screw
N/A
18 (25)
Lubricate threads
21
Diaphragm plate
C1
22
Diaphragm support
B1, B2, C1, C3
23
Diaphragm
B1, B2, C1, C3
24
Dome
N/A
25
Cap screw
E1
11 (15)
Lubricate threads
26
Relief seat O-ring
A1, A2, B1, B2, C1
27
BSP blind plug O-Ring
B1, B2, C1
28
Blind plug
N/A
NPT: 15 (20)
Wrap threads in 2 layers of PTFE
tape. Lubricate tape.
BSP: 26 (35)
Lubricate threads
Table 2
For more information on RHPS series maintenance kits, refer to the Pressure Regulators, RHPS Series,
catalog, MS-02-430.

12
RA4/6/8 Series, Exploded View
Fig 3

13
RA4/6/8 Series, Section View
Fig 4

14
Disassembly
- The following instructions describe how to fully disassemble the regulator for the purposes of
maintenance and repair.
- Note that not all components listed appear in all regulator configurations.
- Only disassemble the regulator as far as is required to replace the components supplied in the
maintenance kit.
- Discard all components being replaced.
1. Remove the body plug (1), poppet spring (4), poppet (7), and seat (8).
2. Remove the O-ring (3) and, if present, backup ring (2) from the body plug (1).
3. Remove the O-ring (6) and backup ring (5) from the poppet (7).
4. Remove the O-ring (9) from the seat (8).
5. Remove the cap screws (25) to remove the dome (24), diaphragm (23), diaphragm support (22), and
diaphragm plate (21).
6. Remove the cap screws (20) to remove the piston plate (18).
7. Remove the piston (13), piston O-rings (14), and piston backup rings (15) from the piston plate (18).
8. Remove the relief seat (12) from the piston (13).
Points of Attention Before Reassembly
- Visually inspect all components for abnormal wear or damage. Replace components in case of doubt.
- All parts must remain clean and undamaged before starting assembly.
- Maintenance kit components will be supplied preassembled where practicable to aid reassembly.
- Swagelok recommends replacing all O-rings removed during disassembly.
- Swagelok recommends that dynamic O-rings should be lightly lubricated per Table 2.
NOTICE
All threaded components must be lightly lubricated per Table 2 before reassembly to avoid
galling of threads.

15
Reassembly
1. Secure the body (10) in a vise.
2. Fit the body plug O-ring (3) and, if present, body plug backup ring (2) onto the body plug (1). Ensure their
orientation is correct per Fig 4.
3. Fit the seat O-ring (9) onto the seat (8).
4. Insert the seat (8) into the body (10). The poppet valve (7) can be used as an insertion tool if required.
Take care not to damage the seat (8) and poppet (7) if doing this.
5. Fit the O-ring (6) and backup ring (5) onto the poppet (7). Ensure their orientation is correct per Fig 4.
6. Lightly lubricate the poppet O-ring (6) then stack the poppet (7) and poppet spring (4) through the seat (8).
7. Lightly lubricate the body plug (1) threads and assemble over the spring (4) into the body (10). Torque to
37 lbf·ft (50 N·m) while ensuring the body plug O-ring (3) is not pinched.
8. Fit the relief seat O-ring (26) over the relief seat (12) then insert the seat into the piston (13). Ensure the
chamfered edge of the seat is facing out.
9. Insert the piston O-rings (14) and backup rings (15) into the piston plate (18). Ensure their orientation is
correct per Fig 4.
10. Lightly lubricate the piston O-rings (14) then insert the piston (13) into the piston plate (18).
11. Place the piston plate O-ring (11) into the body (10) then fit the piston plate assembly, aligning the vent
port as desired.
12. Lubricate the threads of the cap screws (20). Secure the piston plate (18) to the body (10) with the cap
screws (26) and washers (25). Torque to 18 lbf·ft (25 N·m).
13. Place the diaphragm plate (21) on to the piston (13).
14. Place the diaphragm support (22) then the diaphragm (23) onto the diaphragm plate (21).
15. Lubricate the threads of the cap screws (25). Fit the dome (24) onto the diaphragm (23) and secure with
the cap screws (25), washers (17), and nuts (16). Torque to 11 lbf·ft (15 N·m).

16
Testing
Swagelok recommends that the regulator be tested for seat and shell leakage to atmosphere. A well
performing regulator will not show any indication of leaking. If any evidence of a leak is identified this must be
rectified. Any damaged components must be replaced.
Seat Leak Test
1. Ensure there is sufficient supply pressure to the regulator to be able to perform the tests.
2. Ensure that there is zero pressure in the dome.
3. Maintain an inlet pressure of approximately 14.5 psig (1 bar) on the regulator and close the downstream
shutoff valve.
4. Monitor the outlet pressure. An increase in pressure over time indicates a seat leak.
5. Repeat the procedure with the highest inlet pressure applicable for the regulator and system.
Shell Leak Test
1. Maintain an inlet pressure of approximately 29 psig (2 bar) on the regulator and close the downstream
shutoff valve.
2. Increase the outlet pressure to approximately 14.5 psig (1 bar).
3. Using liquid leak detector, check for bubbles at the dome to piston plate interface, piston plate to body
interface body plug to body interface and the self-vent port.
4. Repeat the procedure with the highest inlet and outlet pressure applicable for the regulator and system.

17
Troubleshooting
Symptom
Cause
Remedy
The outlet pressure creeps up,
without adjusting dome pressure.
A damaged poppet and/or
seat.
Replace the poppet and/or seat.
Leakage around the body plug.
A damaged O-ring.
Replace the O-ring.
Leakage around the piston plate.
A damaged O-ring.
Replace the O-ring.
Leakage between the piston plate
and the dome.
A damaged diaphragm.
Replace the diaphragm.
Insufficient torque on the cap
screws.
Tighten the cap screws per Table 2.
Controlled pressure drops off
sharply even when the flow is
within regulator capabilities.
The system filter element is
clogged.
Replace the system filter.
The required outlet pressure
cannot be reached.
The inlet pressure to the
regulator is not high enough.
Ensure that the inlet pressure to the
regulator is equal to or greater than the
desired set pressure.
The outlet pressure rises too
much when going from a dynamic
to a static situation.
There is too much flow in the
dynamic situation.
A larger regulator or parallel regulator is
required.
Review application flow capacity and
contact your local authorized sales and
service center.
The outlet pressure has changed
without adjusting the dome
pressure.
Changes to the inlet pressure
may result in changes to the
outlet pressure.
Maintain a constant inlet pressure to the
regulator. See “Points of Attention
Before Operation” about dependency.
Changes to the flow may result
in changes to the outlet
pressure.
Maintain a constant flow through the
regulator. See “Points of Attention
Before Operation” about droop.
Table 3

18

19

Warranty Information
Swagelok products are backed by The Swagelok Limited Lifetime Warranty.
For a copy, visit swagelok.com or contact your authorized Swagelok representative.
Swagelok, Snoop - TM Swagelok Company
Krytox –TM The Chemours Company
© 2018 Swagelok Company
July 2018, RevB
MS-CRD-0177