Samson EB 01a, Монтаж и эксплуатация

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3-1
EB 01a_EN
March 2023 edition
Subject to technical changes
Design and principle of operation
3 Design and principle of operation
Function and principle of operation
The medium fl ows through the valve against the closing direction.
The position of the plug determines the cross-sectional area be-
tween the plug (13) and the seat (4).
The plug is connected via the stem (16) to the actuator stem.
The PTFE bellows (15) seal the area between the valve body (1)
and the stem (16).
The graphite packing (26) or PTFE V-ring packing (33) is used
for additional stem sealing.
In conjunction with the test connection (24), they allow you to
check the bellows (15) e.g. by connecting a suction line or inert
gas line.
The plug (13) is easy to replace thanks to the groove-spring con-
nection with the bellows in the form of a PTFE cord (14).
The bottom fl ange (10) with inlay (7), PTFE washer (6) and spac-
er (5) house the exchangeable valve seat (4).
Damage to the valve due to cavitation!
The valve can be damaged due to cavitation.
Ö
At the onset of cavitation or with differential pressures above
3 bar and a differential pressure ratio of p2 <
∆ p, PFEIFFER
recommends using a guided plug!
Ö
It is also recommended to use fi ttings made of ceramic or
resistant special metals.
Lined valves are not suitable for operation with cavitation.
Contact PFEIFFER in the case of questions.
Fail-safe positions
Depending on the mounting of the pneumatic actuator, the valve
has two fail-safe positions that are activated when the pressure is
released as well when the supply air fails:
− Valve with spring-close actuator [STAF]:
If the air supply fails, the valve is closed. The valve opens
when the signal pressure increases, acting against the force
of the springs.
− Valve with spring-open actuator [STEF]:
If the air supply fails, the valve is opened. The valve closes
when the signal pressure increases, acting against the force
of the springs.
Changing the fail-safe position
The fail-safe position of the actuator can be reversed if required.
To do so, see the installation and operating manual for the re-
spective pneumatic actuator.
Operating elements and functions
The BR 01a valve can be selected in the following versions:
− With a pneumatic SAMSON actuating drive.
NOTE
− With a manual SAMSON actuator.
− With actuators from other manufacturers.
3.1 Variants
− Valve body warmed with a heating jacket.
− Lining with special compounds, e.g. PTFE-conductive.
− For eroding media, valve plug and valve seat also made of
special material (e.g. tantalum, HC4, titanium or Al
2
O
3
).
− Bellows, stem made of special material (e.g. Hastelloy).
− Further components made of special material.
− Designed for high-permeation media.
− Suitable for crystallising media.
− Low-temperature version for -40°C.
3.2 Additional fi ttings
Strainer
PFEIFFER recommends installing a strainer in front of the valve
body. A strainer prevents the solid content in the medium from
damaging the valve.
Bypass and shut-off valves
PFEIFFER recommends installing a shut-off valve in front of the
strainer as well as behind the valve and to create a bypass. By
means of the bypass, the entire plant does not have to be decom-
missioned during maintenance and repair work on the valve.
Insulation
The valves can be insulated to reduce the passage of heat ener-
gy.
Observe the notes in Chapter “ 5 Assembly”.
Test connection
In the version with bellows sealing, a test connection (e.g. ¼"
thread) can be used on the upper
fl ange to check the tightness of
the bellows.
Grip protection
Under conditions of use that require a high level of safety (e.g. if
the valve is freely accessible to untrained specialist personnel),
PFEIFFER offers a safety guard to prevent the risk of crushing due
to moving parts (actuating drive and plug stem).
The risk assessment of the plant by the operator will indicate if
the installation of this protective device is required for the safe
operation of the valve in the plant.