5
Industrial Valves
Function
LEUSCH LTR 43 butterfly valves usually have a metal seat.
Other material alternative for the seat and seatring are stain-
less steel / graphite, PTFE and stellite. Special coatings and
special materials are available per customer request.
The valve has optimal sealing characteristics when it is
aligned according to the preferred flow direction during instal-
lation in the pipeline system
(Fig. 4)
.
The preferred direction of flow is marked by an arrow at the
side of the valve body.
Thanks to its unique geometric design, the disc is pressed
uniformly against the body seat across its whole surface area.
The valve is adjustable. If subsequent adjustment of the limit
stops becomes necessary (refer also to “Maintenance and
adjustment”), this may only be done by qualified and knowl-
edgeable personnel and with the consent of the manufacturer
The Triple offset is distinguished by the following characteristics:
1. OS (Offset): The shaft bearing has an axial offset to the seat
level, 2. OS: The shaft bearing has a radial offset to the center of
the body, 3. OS: the center of the conical seat surface has a radi-
al offset to the center of the body. (Fig. 4)
Maintenance and adjustment
All measures necessary for maintenance and repair should
be carried out in accordance with the national regulations of
the destination country.
It is recommended to check the device regularly for external
leaks and other adverse effects or anything conspicuous.
The Gland Packing usually consists of a set of form-pressed
expandable rings. In the event of a leakage, the nuts on the
Gland must be alternately tightened in little steps until the
leak stops. It has to be ensured, that the gland is always par-
allel to the body surface (Fig 5).
If necessary, add additional packing rings. Observe the maxi-
mum permissible torques (see “Replacing the Gland pack-
ing”) or Page 8 table 1, if only torque values are required.
Complete Packing and repair sets for maintenance of the
valves are available from LEUSCH or/and the authorised
LEUSCH representative.
Before contacting your representative or Leusch GmbH,
please make a note of all the details on the name-plate of the
valve (Fig. 11).
ATTENTION: DANGER! Spring return actuators may only be
pressurised only when assembled in the pipeline and not for
the purposes of performance of work on the valve outside the
pipeline. There is a risk of fatal injury if the auxiliary energy
suddenly fails and the valve disc then moves on its own into
the fail-safe position as a result of spring tension.
For devices equipped with a spring return actuator with Fail
Open safety position, the valve disc may possibly need to be
closed for installation in a pipeline. It must be ensured here
that the full control pressure for closing the valve is main-
tained for the duration of the installation work.
Otherwise, the valve must be installed in the open
position, e.g. by dismantling the pipeline.
Caution should be taken also on devices with
spring-return actuators, for example, that does not
carry out any function
due to being clamped in place and therefore re-
main in any closed/open position. The return
spring could be decompressed at any moment
without active/connected auxiliary energies thus
setting the valve disc in motion.
LEUSCH valves may only be assembled, put into
operation and maintained by specialist and trained
personnel in accordance with recognised technical
rules. Ensure that employees and third parties are
not endangered. The operator must define the
necessary measures for maintenance in the oper-
ating instructions. All safety or warning instructions
detailed here and in the product instructions (e.g.
operating and maintenance instructions) must be
followed.
For valves which are used in oxygen service, all
maintanance and repair works has to be carried
out in an oil-and greasefree enviroment. All parts
mus be clean and free from oil and grease. Only
suitable lubricants are permitted.
Fig. 4
Fig. 5