Swagelok RHPS Series User manual

RHPS Series
LPRD20 - 40
User Manual
Read the complete manual before installing and using the regulator.

WARNING
Before removing a regulator from the system for service, you must
Depressurize system
Purge the system to remove any residual system media left in the regulator.
Contents
Introduction ............................................................................................................................................... 3
Installation ................................................................................................................................................. 4
Operation ................................................................................................................................................... 7
Maintenance .............................................................................................................................................. 9
Testing ..................................................................................................................................................... 10
Troubleshooting ...................................................................................................................................... 11
2

Introduction
Representative drawing of a standard LPRD25
1 body assembly 11 guide ring 22 O-ring
2 dome cover 12 retaining ring 24 ring
3 body plug 13 valve spring 25 nut
4 valve case 14 O-ring 26 socket head cap screw
5 valve screw 16 diaphragm 27 ring
6 push rod 17 valve insert 28 nut
7 body plate 18 guide bush
8 diaphragm plate 19 O-ring
9 diaphragm screw 20 O-ring
10 seat 21 O-ring
3

Installation
WARNING
When installing a Swagelok®self-venting regulator, position the vent connection or line away
from operating personnel. Operating personnel must protect themselves from exposure to system
fluids.
CAUTION
Do not use the regulators as a shutoff device.
The preferred mounting position of the regulator is horizontal with the dome facing upwards.
If grounding is required, connect a ground wire under a dome bolt.
Filling the dome
The dome can be filled using manual or electronic loading.
Manual loading:
This can be done by taking the gas pressure from the system and feeding this through a spring
loaded pilot regulator into the dome. This is shown in sketch A.
In liquid systems the gas pressure for manual dome loading can be taken from a cylinder or mains.
This is shown in sketch B.
Substituting the spring loaded pilot regulator for a proportional control valve and a pressure sensor,
allows you to control the pressure electronically.
Electronic loading:
This can be done by taking the gas pressure from the system and feeding this through a proportional
control valve into the dome. This is shown in sketch C.
This method can be used for low and medium-pressure systems.
This can be done by taking the gas pressure from the system and feeding this through a proportional
controlled ratio regulator into the dome. This is shown in sketch D.
This method can be used for high-pressure systems.
The best results will be achieved by allowing a small flow to continuously pass through the pilot regulator.
This flow can either be vented or, in gas systems, fed back through an orifice into the downstream piping.
This is usually referred to as “dynamic regulation”.
It is not recommended to place a gauge on the dome to set or check the outlet pressure.
Because of forces in the regulator, the dome pressure will always be higher than the outlet
pressure. Place a gauge in the outlet line to set or check the outlet pressure.
4

5

External feedback
CAUTION
When using the regulator with external feedback, make sure that the outlet pressure can be
fed back to the external feedback connection before applying pressure to the regulator.
Failing to do so may lead to damage and non-functioning of the regulator as the inlet
pressure will be put straight through to the outlet.
The purpose of the external feedback on a pressure regulator is to get a more accurate regulation of the
outlet pressure. This can be achieved by sensing the outlet pressure downstream of the regulator and
feeding it back to the regulator.
CAUTION
Never connect the external feedback line downstream of a shut-off valve.
Principle sketch of external feedback:
6

7
Operation
Make the final pressure setting in the direction of increasing pressure to obtain the most accurate set
points.
Once fluid is flowing through the system, fine tuning may be required.
Icing of the regulator at high flow rates or high pressure drops may occur if the gaseous media or
atmosphere contains moisture.
An auxiliary upstream filter is recommended for use in all but the cleanest of media.
Installation of a downstream pressure relief is recommended for regulator and system protection.
If the shut-off valve at the outlet side is closed after changing the set pressure, the outlet pressure will
rise a little because of the closing force required for bubble-tight closing of the regulator.
This phenomenon is usually referred to as the “lock-up” and does not indicate a problem with the
regulator.
A decrease in the flow will result in a rise of the outlet pressure.
An increase in the flow will result in a fall of the outlet pressure and is usually referred to as the
“droop”.
This phenomenon does not indicate a problem with the regulator.
A decrease of the inlet pressure will result in a rise of the outlet pressure.
An increase of the inlet pressure will result in a fall of the outlet pressure.
This phenomenon is usually referred to as the “dependency” and does not indicate a problem with
the regulator.
Each regulator type has its own dependency, which is related to the ratio between the effective seat area
and the sensing area.
Dependency Ratio’s LPRD20, 25, 30 & 40
Type Dependency
ratio
0.1-1 bar (PR2) 1/920
LPRD20
+
LPRSN4 0.3-2 bar (PR3) 1/920
0.1-1 bar 1/800
LPRD25
+
LPRSN4 0.3-2 bar 1/800
0.1-1 bar 1/420
LPRD30
+
LPRSN4 0.3-2 bar 1/420
0.1-1 bar 1/520
LPRD40
+
LPRSN4 0.3-2 bar 1/520
The approximate change can be calculated as shown below:
ΔP2 = ratio x ΔP1
A ratio of 1/X means that for every pressure change to P1 of X bar, the P2 pressure will change 1 bar:

Changing the set pressure
Check the supply of medium at the inlet side.
CAUTION
When using the LPRD20, 25, 30 or LPRD40 with an inlet pressure higher than 2 bar, a safety
valve must be installed in the outlet line, because the outlet pressure may not exceed 2 bar.
Make sure the inlet pressure is higher than the required outlet pressure and that the inlet
pressure does not exceed the maximum allowed inlet pressure. Open the shut-off valve at the
inlet side.
Open the shut-off valve at the outlet side slightly to allow a minimal flow.
Controlled outlet pressure settings are obtained by adjusting the pressure in the dome.
Increasing the pressure in the dome raises the outlet pressure while decreasing the pressure
in the dome lowers the outlet pressure.
Notice
A shut-off valve on the outlet side must be opened to relief the pressure on the outlet side.
Final adjustment must be made while increasing the pressure in the dome to obtain the most
accurate set point(s).
Open the shut-off valve at the outlet side to allow full flow during operation.
8

Maintenance
Required tools for maintenance
a vice to fasten the regulator
pincers to take out the O-rings
a pair of tongs for a retaining ring 95 mm (LPRD20&25 only)
a pair of tongs for a retaining ring 140 mm (LPRD30&40 only)
a torque wrench
a torque wrench hexagon head key 10 mm for the body plug (LPRD30&40 only)
a torque wrench hexagon head key 5 mm for the dome cover bolts
a torque wrench “open-end insert tool”, 46 mm for the body plug (LPRD20&25 only)
open-end spanners 11/16, 3/4 and 7/8 inch(for compression fittings)
open-end spanners 10 and 17 mm (for dome cover nuts and dome screw)
media and temperature compatible lubricant for reassembling threaded parts
media and temperature compatible lubricant for O-rings
Snoop®liquid leak detector
Notice
A shut-off valve on the outlet side must be opened to relief the pressure on the outlet side.
Disassembly instructions
Loosen the hexagon socket head screws and remove the dome cover.
Lift out the diaphragm, along with the diaphragm plates/ -screw
Loosen the body plug and remove the valve assembly, valve spring and seat.
Inspection of disassembled parts
Check all parts for abnormal wear. Replace parts in case of doubt.
Points of attention before assembly
All parts must be clean and undamaged before starting assembly.
Swagelok recommends replacing all O-rings and the diaphragm before assembly.
All threaded parts must be lightly lubricated before assembly, this to avoid galling of threads.
All O-rings need to be lightly lubricated to improve the lifetime of the O-ring and the performance of
the regulator.
Assembly instructions
Follow the points for disassembly in reverse order to assemble the regulator.
9

Recommended torques
CAUTION
Only tighten the bolts or parts if the regulator is completely depressurized.
Hexagon socket head screws M12 (body plug) 50 N·m (442 in.·lb) (LPRD30&40 only)
Body plug 50 N·m (442 in.·lb) (LPRD20&25 only)
Dome cover screws M6 15 N·m (132 in.·lb)
Testing
Check the regulator for leakage across the seat, with low- and high inlet pressure.
Check the regulator for leakage across the connectors and plugs, with low- and high inlet pressure.
Check the regulator for leakage across the diaphragm, with low- and high outlet pressure.
Notice
When using the LPRD20, 25, 30 or LPRD40 with an inlet pressure higher than 2 bar, a safety
valve must be installed in the outlet line, because the outlet pressure may not exceed 2 bar.
A well performing regulator is 100% bubble tight.
10