SIEMENS
FLENDER Standard Couplings
Highly Flexible Couplings — ELPEX-S Series
General information
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Siemens MD 10.1 · 2015
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Overview
Coupling suitable for use in potentially explosive
atmospheres.
Complies with the current ATEX Directive for:
II 2 G T3 D160 °C X
II 2 G T4 D120 °C X
(Type EST is not available in Ex version.)
ELPEX-S couplings are highly torsionally flexible and because of
their low torsional stiffness and damping capacity are especially
suitable for coupling machines with a highly non uniform torque
pattern.
Standard ELPEX-S coupling types are designed as flange-shaft-
connections or shaft-shaft connections. Application-related
types can be implemented on request.
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Benefits
The ELPEX-S coupling is suitable for horizontal and vertical
mounting positions or mounting at any required angle. The cou-
pling parts can be arranged as required on the shafts to be con-
nected.
ELPEX-S couplings are especially suitable for reversing opera-
tion or operation with changing directions of load.
The rubber disk elements are fitted virtually without backlash
and give the coupling linear torsional stiffness, i.e. the torsion
stiffness remains constant even when the load on the coupling
increases.
There are 4 different rubber element versions with different
grades of torsional stiffness available for each size from stock.
On certain types the flexible rings can be changed without hav-
ing to move the coupled machines.
If substantial overload occurs, the rubber disk element of the
coupling is irreparably damaged, the coupling throws the load
and thus limits the overload for particular operating conditions.
The coupling can be inserted and fitted blind e.g. in a bell hous-
ing.
There are outer flanges with different connection dimensions
available for each coupling size.
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Application
The ELPEX-S coupling is available as a catalog standard in 12
sizes with rated torques of between 330 Nm and 63000 Nm.
The coupling is suitable for ambient temperatures of between
-40 °C and +120 °C.
The ELPEX-S coupling is frequently used for diesel motor drives
or reciprocating compressor drives. Because the different rub-
ber versions enable the torsional stiffness to be adjusted to meet
requirements, the coupling is also suitable for drives which re-
quire a specific and preferably precalculated torsional vibration
behavior setting.
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Design
The rubber disk element is vulcanized onto a flange on the in-
side diameter. The flange can mount e.g. a Taper clamping bush
or a hub. On its outer diameter the rubber disk element has driv-
ing teeth, which are inserted into the outer flange. The torque is
transmitted positively between the rubber disk element and the
outer flange.
In the type for shaft-shaft connection the outer flange is screwed
to a flange hub mounted on a machine shaft.
Materials
Elastomer materials of the rubber disk element
ELPEX-S coupling types
Type EST
Types ESN. and ESD.
Rubber disk element
Grey cast iron
EN-GJL-250/elastomer
Spheroidal graphite
cast iron
EN-GJL-400/elastomer
Hubs, part 1, part 2
Steel
Steel
Outer flange
Cast aluminum
AlZnSi108..
Sizes 680 and 770
of spheroidal graphite
cast iron
EN-GJS-500
Cast aluminum
AlZnSi108..
Sizes 680 and 770
of spheroidal graphite
cast iron
EN-GJS-500
Material / description
Hardness
ShoreA
Iden-
tifica-
tion
Ambient
temperature
Natural-synthetic rubber mixture
50 ° … 55 ° WN
-40 °C … +80 °C
Natural-synthetic rubber mixture
60 ° … 65 ° NN
-40 °C … +80 °C
Natural-synthetic rubber mixture
70 ° … 75 ° SN
-40 °C … +80 °C
Silicone rubber
55 ° … 65 ° NX
-40 °C … +120 °C
Type
Description
ESN
Coupling with hub, long or short version
ESD
Coupling with hub, with two rubber disk elements
ESNR
Coupling with hub, rubber disk element radially dismountable
ESDR
Coupling with hub with two rubber disk elements; rubber disk
elements radially dismountable
ESNW
Coupling designed as a shaft-shaft connection with a rubber disk
element; rubber disk element radially dismountable
ESDW
Coupling designed as a shaft-shaft connection with two rubber disk
elements; rubber disk element radially dismountable
EST
Coupling suitable for mounting a Taper clamping bush
© Siemens AG 2015