11
Sempell
SerieS STe 4 ConTrol DeviCe for SafeTy valveS
Operating instructiOns
7.2 assembly
The delivery of the control device STe 4 takes
place assembled on a frame tightened by eight
screws.
at delivery the key of the front doors is placed
at the connection for the compressed-air
supply of the control unit. further keys are
behind the front door of the electric switch unit.
It is only allowed to operate the control device
STE 4 by an air pressure of max. 8 bar. For the
special design with pressure regulator R2 the
lifting air can be up to max. 12 bar.
The control device has to be easy accessible to
facilitate adjusting and inspection. Protect the
location of the installation against wet and dirt.
Do not mount control device too close to the
safety valve (distance at least 3 m). for remote
location consider the delay times (see vdTÜv-
regulation ...-846).
7.3 pressure sense line
To connect the pressure sense line the
control device has three pressure connections
(e1, e2, e3). The pertaining tube fittings
(attached to delivery) have a welding connection
DA Ø 21.3 x 4 out of 316SS (similar to 1.4401).
It is possible to weld adequate pipe profiles
on these connections. The tube fittings have
to be assembled according to the instructions
(see section 9.3).
if desired special connections and materials
are deliverable (request).
The inner diameter of the pressure tapping line
must be at least 15 mm.
The pressure connection has to take place
above an flexable laid line. In case of fixed line
bracings between pressure sense line and
welding connection of the control device it
may cause switch inaccuracy of the pressure
switches.
Guarantee by suitable measures that no
vibration can be transferred to the control
device. Dampen vibrations or pressure peaks
out of the medium by switch on throttles.
Connection of the sense line in the system:
for preventing too great pressure deviations
observe following instructions:
• If possible, connect not directly at the safety
valve inlet
• Connection of the system part to be secured
on a point with as great volume as possible
and as little as possible pressure fluctuations.
The power supply of the heater can be
disconnected by an additional switch.
for outdoor installation additionally protect the
system from direct exposure of sunlight.
after commissioning check the pressure sense
lines up to the pressure switch on tightness.
Upstream each pressure switch (D1, D2, D3)
there is a corresponding shut-off valve
(a1, a2, a3) in the impulse unit of the control
device. With these it is possible to close one
pressure tapping line for adjustment works.
The shut-off valves are secured by the valve
interlock (G) in such a way that only one
pressure switch can be put out of operation.
The other pressure switches remain in service
(see connection diagram section 9.2).
The test connections (P1, P2, P3) allow the
connection of a spindle pump with pressure
gauge to adjust and control the switch points
(see section 4.7.1).
pressure test in the system
The components in the impulse unit a161 are
connected to system pressure through the
pressure sense lines. The pressure switches
(D1, D2, D3) may be loaded with a test pressure
up to 1.5× the end of scale value.
attention!
Take care that no vibrations of the structure are
transferred to the control device as they can
fraudulently alter the measured value (switch
point). If necessary, install vibration dampers, e.g.
rubber buffers.
attention!
Also when the control unit is switched off by
the main switch (lockable switch), the heating
remains energized.
in case of pressure sense lines coming from
different systems (e.g. drum, superheater), take
care of the correct connection at the impulse
unit (different pressure setting of pressure
switches).
Prevent undue heating up of the control device
in case of connecting the control device at
pressure tapping lines with hot medium. The
temperature at the impulse unit inlet may not
exceed 60°C.
for steam as medium, connect via syphons or
water locks before the control device. Therefore
lay pressure sense line so that condensate can
be formed. The pressure sense line close to the
control unit may not be insulated.
Protect lines and control device from freezing.
If the impulse unit A161 is provided with
a heating (accessory H1, H2), observe the
following points:
at danger of freezing assure that the control
unit is always energized.
