Samson EB 20b, Mounting And Operating Instructions

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3-1
EB 20b_EN
February 2022 edition
Subject to technical changes
Design and principle of operation
3 Design and principle of operation
Function and principle of operation
The media can fl ow in both directions through the BR 20b ball
valve with full passage.
The ball (3) with its cylindrical passage is swivel-mounted around
the switching shaft. The ball swivel angle in
fl uences the fl ow
through the area freed between the body and the ball channel.
When the ball valve is open, the full cross section is freed.
The ball (3), in the PFA lined body, is sealed by replaceable seal
rings (4).
The switching shaft is sealed by PTFE V-ring packing (5). The
spring washers (8) located above the packing provide the preten-
sioning.
The switching shaft that leads outside is fi t up to DN 100/NPS4
with a hand lever. Optionally, a pneumatic rotary actuator or a
manual gear can be installed.
The ball valve can also be used for control purposes see the data
sheet

DB 20a-kd.
Fail-safe position
Depending on the mounting of the pneumatic rotary actuator, the
ball valve has two fail-safe positions that are activated when the
pressure is released as well when the supply air fails:
− Ball valve with fail-close actuator [FC]:
Upon air failure, the ball valve is closed. The ball valve opens
when the signal pressure increases, acting against the force
of the springs.
− Ball valve with fail-open actuator [FO]:
Upon air failure, the ball valve is opened. The ball valve clos-
es 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,
for this purpose see the installation and operating instructions for
the respective pneumatic actuator.
Operating elements and functions
The BR 20b ball valve can be selected in the following versions:
− With a hand lever (DN 15 up to 100 or NPS1 up to 4).
− With a manual gear.
− With PFEIFFER rotary actuator BR 31a.
− With rotary actuators from other manufacturers (for details
see the respective data sheet).
3.1 Variants
− Body made of other materials, e.g. 1.4571
Info
− Use as a control ball valve with calibrated seat ring
(
≤ DN 100)
− PFA-conductive lining
− Stainless steel heat pack
− Various ball and seal ring materials
− FDA-compliant sealing material
− Two-part ball/switching shaft
− Customer-adapted versions
3.2 Additional fi ttings
Strainer
PFEIFFER recommends installing a strainer in front of the ball
valve. A strainer prevents the solid content in the medium from
damaging the ball valve.
Bypass and shut-off valve
PFEIFFER recommends installing a shut-off valve in front of the
strainer as well as behind the ball valve and to create a bypass.
By means of the bypass, the entire plant does not have to be de-
commissioned during maintenance and repair work on the ball
valve.
Insulation
The ball valves can be insulated to reduce the passage of heat
energy. If necessary, observe the notes in Chapter “5.4 Installing
the ball valve in the pipe”.
Grip protection
In the case of conditions of use that require a high level of safety
(e. g. if the ball valve is freely accessible to untrained specialist
personnel), PFEIFFER offers a safety guard to prevent the risk of
crushing due to moving parts (actuator- and switching shaft).
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 ball valve in the plant.
3.3 Attachments
The following accessories are available for the ball valve either
individually or in combinations:
− Locking device
− Switching shaft extension (100 mm standard)
− Pneumatic or electric rotary actuator
− Positioner (with the control ball valve option)
− Limit switch
− Solenoid valves
− Filter - reducing station
− Control ball valve with calibrated seat ring
Other additional equipment is possible according to speci fi ca-
tions on request.