Samson 42-34, 42-38 Mounting And Operating Instructions
Self-operated Regulators
Differential Pressure Regulators with
Flow Limitation
Type 42-34 · Type 42-38
Type 42-34
Type 42-38
Mounting and
Operating Instructions
EB 3013 EN
Edition July 2009
Contents
Contents Page
1 Design and principle of operation . . . . . . . . . . . . . . . . . . . . . . 4
2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Mounting position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Strainer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 Shut-off valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Pressure gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5 Control line, equalizing tank and needle valve . . . . . . . . . . . . . . . . 8
3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Set point adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.1 Adjusting the differential pressure . . . . . . . . . . . . . . . . . . . . . . 10
3.2.2 Adjusting the flow restriction . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.3 Pressure conditions in the plant and regulator . . . . . . . . . . . . . . . . 12
3.3 Decommissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 Maintenance · Troubleshooting . . . . . . . . . . . . . . . . . . . . . . 18
4.1 Replacing the operating diaphragm . . . . . . . . . . . . . . . . . . . . 19
5 Nameplates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6 Dimensions and weights. . . . . . . . . . . . . . . . . . . . . . . . . . 22
7 Customer service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8 Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Definitions of the signal words used in these instructions
WARNING!
WARNING indicates a hazardous situation
Note: Supplementary explanations, informa
tion and tips
which, if not avoided, could result in death or
serious injury.
NOTICE
NOTICE indicates a property damage
message.
2 EB 3013 EN
-
Safety instructions
General safety instructions
The regulators must be installed, started up and serviced by fully trained and
4
qualified personnel only, observing the accepted industry codes and practi
ces. Make sure employees or third persons are not exposed to any danger.
The regulator complies with the requirements of the European Pressure Equip
4
ment Directive 97/23/EC. The declaration of conformity issued for a valve
bearing the CE marking includes information on the applied conformity as
sessment procedure.
The declaration of conformity can be provided on request.
For appropriate operation, make sure that the regulator is only used in appli
4
cations where the operating pressure and temperatures do not exceed the
operating values based on the sizing data submitted in the order.
Note that the manufacturer does not assume any responsibility for damage
4
caused by external forces or any other external factors.
Any hazards whichcould be causedin the regulatorby the processmedium or
4
operating pressure are to be prevented by means of appropriate measures.
Proper shipping and appropriate storage are assumed.
4
-
-
-
-
Note: Non-electric valve versions which do not have a valve body lined with an insulating coa
ting donot have theirown potential ignitionsource according tothe ignition risk assessment sti
pulated in EN 13463-1: 2001, section 5.2, even in the rare incident of an operating fault. The
refore, they do not fall within the scope of Directive 94/9/EC.
For the connection to equipotential bonding, observe section 6.3 in EN 60097-14: 1977
(VDE 0165, Part 1)
EB 3013 EN 3
-
-
-
Design and principle of operation
1 Design and principle of
operation
The differential pressure regulators are used
to maintain the differential pressure between
the high-pressure and the low-pressure pipe
at a set point which is either fixed (Type
42-38) or adjustable (Type 42-34). The re
striction built into the valve body allows for
limitation of the flow rate.
The regulators basically consist of a valve
with a seat, plug and restriction as well as a
closing actuator with an operating dia
phragm. The valve and actuator are deliv
ered in separate packaging and need to be
connected on siteusing the coupling nut(11).
The process medium flows through the valve
in the direction indicated by the arrow. The
free areasof flow releasedby the orifice(1.4)
and the valve plug (3) determine the flow rate
.
and the differential pressureΔp
V
the plant.
Fully balanced valves ensure that the up-
stream and downstream forces acting on the
valve plug are eliminated by a balancing bel
lows (5) or a balancing diaphragm (5.1). The
principle of operation of the regulators with
valves balanced by a bellows or by a dia
phragm only differ concerning their pressure
balancing. Valves balanced by a diaphragm
(DN 125 to 250 only) have a balancing dia
phragm instead of a balancing bellows (5).
The pressure downstream of the orifice (1.4)
acts on the outer surface of the metal bellows
plant
across
or balancing diaphragm and the down
stream pressure on the inside of the bellows
or diaphragm. As a result, the forces created
by the upstream and downstream pressures
acting on the valve plug are equally bal
anced.
The regulators in sizes DN 15 to 100 are
-
equipped witha connecting piece(10) forthe
low-pressure control line between the valve
and the actuator.
In differential pressure control, the high pres
sure (flow) of the plant is transmitted to the
bottom diaphragm chamber of the actuator
over the high-pressure control line. The pres
sure downstream of the orifice (1.4) acts on
the top diaphragm chamber over the hollow
plug stem and the connected low-pressure
control line. The differential pressure is converted into a positioning force at the diaphragm (13) and is used to change the position ofthe valve plug according to theforce of
the set point springs (16). Depending on the
version of the actuator, the set point springs
are installed in the actuator to provide a fixed
set point (Type 42-38), or they are located
outside to allow the set point tobe adjusted as
required (Type 42-34).
-
The restriction (1.1) is used to adjust the flow
limitation.
The force limiter (20) as well as the internal
excess pressure limiter (21) are designed to
protect the seat (2) and plug (3) against over
load in caseof extreme operating conditions.
-
-
-
-
-
Table 1 · Regulator configuration
Controller = Valve + Actuator
Type 42-34 with connecting piece (
Type 42-38 with connecting piece Type 2423 Balanced Type 2428 Fixed set point
for DN 15 to 100) Type 2423 Balanced Type 2424 Adjustable set point
4 EB 3013 EN
Design and principle of operation
Type 42-34
Type 42-34, Type 42-38 · Balanced by a bellows
DN 15 to 250
Type 2423 Valve
balanced by a bellows
Type 2424
Type 2428 Actuator
Actuator
1 Valve body
1.1 Restriction (for flow rate
set point adjustment)
1.2 Lock nut
1.3 Cap
1.4 Orifice
2 Seat
3 Plug
4 Plug stem
5 Balancing bellows
7 Spring
8 Venting
(DN 125 and larger)
Fig. 1 · Schematic diagrams of regulator with valve balanced by a bellows
Type 42-38
DN 15 to 100
9 Low-pressure control line
(up to DN 100)
9.1 Low-pressure control line
connection (DN 125 and larger)
10 Connecting piece (up to DN 100)
11 Coupling nut
12 Diaphragm stem
13 Operating diaphragm
14 Actuator housing
15 Screws
16 Set point springs
17 Set point adjustment (screw)
18 Nut
19 Diaphragm plate
20 Force limiter
21 Internal excess pressure limiter
EB 3013 EN 5
Installation
Type 2423 Valve
balanced by a
diaphragm
Type 42-34 · Balanced by a diaphragm · DN 125 to 250
Type 2424
Actuator
1 Valve body
1.1 Restriction (for flow rate
set point adjustment)
1.2 Lock nut
1.3 Cap
1.4 Orifice
Fig. 2 · Schematic diagrams of regulator with valve balanced by a diaphragm
2 Installation
See Figs. 1 and 2
The regulator must be installed in the return
flow pipe as shown in the installation sche
matic in Fig. 5.
When choosing the place of installation, en
sure the regulator can be easily accessed af
2 Seat
3 Plug
4 Plug stem
5.1 Balancing diaphragm
11 Coupling nut
12 Diaphragm stem
-
-
-
NOTICE
The regulator mustbe installed freeof stress. If
necessary, support the piping near the con
nections. However, do not attach supports to
the valve or actuator.
ter completion of the plant.
6 EB 3013 EN
-
Installation
Note: Install a strainer (e.g. SAMSON
Type 2 N/2 NI) upstream of the regulator to
prevent sealing particles, welding spatter or
other impurities carried along by the process
medium from impairing the proper function
ing of the valve, especially tight shut-off.
2.1 Mounting position
See Fig. 3 for permissible mounting positions.
Standard installation · Install the valve with
out the actuator in a horizontal pipeline with
the connection for the actuator facing downwards. Make sure the medium flows through
the valve in the direction indicated by the arrow. Then connect the actuator (and the connecting piece (10) for versions in sizes DN 15
to 100) to the valve using the coupling nut
(11).
–
Standard mountingposition
– all versions –
–
All versions
up to max. 80 °C
NOTICE
Protect the regulator when it is used to control
freezing process media.
On shutting down the plant in areas not free
from frost, depressurize and empty the regu
lator and remove it from the pipeline.
2.2 Strainer
A strainer installed in the flow pipe (Fig. 5)
prevents foreign matter and dirt particles in
the medium from entering the regulator. The
SAMSON product range includes the
Type 2 N/2 NI Strainer (refer to Data Sheet
T 1010 EN).
Install the strainer upstream of the regulator.
Make sure the direction of medium flow corresponds with the direction indicated by the
arrow on the strainer. The filter element must
be suspended downwards. Remember to
leave enough space to remove it.
2.3 Shut-off valve
We recommend installing a hand-operated
shut-off valve (Fig. 5) both upstream of the
strainer and at the outlet of the return flow
pipe to be able to shut down the plant for
cleaning and maintenance, and when the
plant is not used for longer periods of time.
-
–
Only versions with fixed
plug guide and
up to max. 80 °C
Fig. 3 · Permissible mounting positions
2.4 Pressure gauge
To monitor the pressures in the plant, install a
pressure gauge both upstream and down
stream of the regulator (Fig. 5).
EB 3013 EN 7
-
Installation
2.5 Control line, equalizing tank
and needle valve
Control lines · After mounting the actuator,
fasten the supplied high-pressure control line
to the regulator (standard: 8 mm pipe diame
ter) routing it from the bottom diaphragm
chamber to the high-pressure line (flow pipe)
of the plant. Attach the low-pressure control
line to the regulator as shown in Figs. 1 and
2.
The controlline to be installed on site for pres
sure tapping at the pipeline must be at least
three times the nominal size (DN) away from
pipe fittings or instruments thatcause flow tur
bulence (e.g. pipe bends, manifolds,pressure
measuring points or other valves) (see Fig.
4.1). How the lines are routed generally de-
pends on the installation location. Preferably
connect the control line at the side of the main
pipeline (Fig. 4.4).
Do not change the pipe diameter of the main
pipeline so that it is off-center!
Control line kit · A control line kit for tapping
pressure directly at the valve body is avail
able as an accessory from SAMSON. Refer to
Data Sheet T 3095 EN.
Equalizing tank · An equalizing tank is re
quired for liquids above 150 °C. Install an
equalizing tank in the control line directly
downstream of the pressure tapping point.
The mounting position of the equalizing tank
is indicated by an adhesive label on the tank
itself as well as by an arrow and the word
"top" stamped onto the top of the tank. Ad
here to the mounting position and distances
prescribed, otherwise the safe functioning of
the regulator cannot be guaranteed.
Correct!
-
4.4 · Connection at the side – correct
Incorrect!
-
4.3 · Connection at the top – incorrect
-
Incorrect!
4.2 · Connection at the bottom – incorrect
-
-
-
DN = Nominal size
4.1 · Control line connection, depending on how
the pipeline is routed
Fig. 4 · Control line connection
8 EB 3013 EN
Loading...