Mission-Critical Couplings - Kop-Flex - #4

oil can get hot if heat exchange and cooling do not occur. The oil smokes and "cooks" on the coupling, turning it black (Figure 7).

The best guard design

It is extremely important to design the guard with as much clearance around the coupling as possi­ble. This is not always easy to do because of con­straints such as piping, but it is the most effective way to reduce windage related problems. Note in Figure 8 the generous clearance around the cou­pling and the distance from the coupling to the housing. This coupling is not an anti-windage design (the disc pack is uncovered). In contrast, Figure 9 shows a tight fitting coupling incorpo­rating special guard and coupling features to eliminate excess oil ingestion and windage.

If the coupling needs to operate in a tight guard at high-speed, consult papers such as "The Design of Coupling Enclosures," avail­able on the Kop-Flex web site (http://www.emerson-ept.com/eptroot/kopflex/default.asp) , or other manufacturers' reference materials to design a properly functioning guard. Also note that if the guard temperature cannot be lowered to acceptable levels for safety precautions, and it is still acceptable as far as the oil is concerned, an expanded metal guard similar to Figure 10 can be placed over the first guard. H

Footnote

Author

Joe Corcoran is manager of High Performance Engineering for Kop-Flex, Inc., a division of Emerson Power Transmission. The group he heads selects and designs couplings, and processes orders and inquiries for high-performance cou­plings and torquemeters. Previous to his 19 years at Kop-Flex, he was an operations engineer responsible for two 80 ton-per-day Union Carbide-Linde oxygen plants at Baltimore.