Note about ATEX compliance
Both series are ATEX certificated, but importantly it must be noted that the N-Eupex coupling is ATEX compliant as long as the coupling is operated in accordance with the installation, operation and maintenance manual. More importantly the maintenance aspect, replacing the elastomers prior to failure. This is due to the fail-safe design allowing torque transmission should the elastomers fail.
If complete ATEX safety is required, without needing to adhere to the N-Eupex maintenance requirements, then the N-Eupex DS is the coupling to use.
Coupling suitable for use in potentially explosive atmospheres.
Complies with the current ATEX Directive for:
II 2G Ex h IIC T6 ... T4 Gb X
II 2D Ex h IIIC T85 °C ... 110 °C Db X
I M2 Ex h Mb X
A new type, N-EUPEX DK, added to the modular principle of N-EUPEX and the performance & bore capacity of all types increased.
Double-cardanic system.
With the new double-cardanic design, the coupling compensates for not only a greater range of shaft angle offsets, but also a considerably greater radial offset so that shaft ends can be connected in a manner that offers the drive greater protection. With this two-joint version, compensation for radial offset that occurs between the shaft ends is enabled by a corresponding angle of inclination in the elastomer joints. This increases the range of possible radial offset by more than a multiple of four. Especially with pump applications, shaft ends that are not 100% in alignment present a significant problem. In this case, the N-EUPEX DK provides a solution for many problems because, depending on the coupling length and size, it enables compensation for a radial offset of up to 3 millimetres. Furthermore, in contrast to the previous N-EUPEX, the new coupling type "DK" makes use of not just one, but two series of elastomer elements, which guarantees increased damping over the entire drive train. In addition, due to the double-cardanic design, significantly lower restoring forces are generated. The high ratio of shaft and joint clearance also decreases the restoring forces. Depending on size, offset and installation dimensions, the restoring forces decrease by more than half. The result is a lower load on the shafts along with a lower load on the bearings. This is advantageous especially with thinner shafts, which can be damaged due to the wrong coupling design or improper installation, even up to the breakage point. The spacer, made of aluminum with a joined pocket part made of gray cast iron, comes in standard increments for shaft spacing from 100 mm to 250 mm, so its length can be adapted to the customer's design.

For coupling fatigue torque: TKW = 0.15 x TKN, where TN > TW must be adhered to.
FLENDER has succeeded in increasing both the performance and the bore capacity of the entire N-EUPEX series by nearly one-third. As a result, users benefit from greater torque, higher rotation speeds and a change in size. The N-EUPEX series has proven itself for decades as a standard solution, and it has now been elevated to a new level of connector technology.
Details of the N-EUPEX range found in the technical specification catalogue. Link found below . . .
Technical specification of new N-EUPEX DK couplings found in this on-line »
catalogue « link