Coupling for 400 H.P., 300 R.P.M. Motor / Single Piston Reciprocating Compressor. Both Shafts were 6" Diameter

Problem:

An old style rubber tire coupling had failed due to age and fatigue. A replacement rubber tire that would fit this particular coupling could not be obtained since the manufacturer was no longer in business.

Possible Solutions:

• Have a rubber manufacturer mold a custom rubber tire for this particular size and style coupling. This would involve a lengthy process and would be very costly for just 1 or 2 pieces.
• Replace the coupling. This seemed the best solution and so the customer went ahead and installed a new gear spacer coupling. During the field test a loud chattering noise was detected coming from the coupling and traveling throughout the installation. The unit was stopped and Frontline was called in.

Frontline’s Solution:

Due to the specific application where the driven shaft of the reciprocating compressor actually stops for a fraction of a second twice every revolution, a gear coupling was definitely the wrong choice.

A more appropriate coupling would have have been an elastomeric type coupling with the elastomeric elements in pre-compression.

Frontline's Big Boy^® design with rubber coated bushings was just the right choice. Frontline prepared the 16" O.D., 6" bore Spacer coupling and sent its technicians to remove the gear coupling and install the Big Boy^® coupling.

The unit was tested and ran very quietly without any vibration whatsoever.

Click on the images below to enlarge

1. Gear couplings hubs still in place.	2. Shafts being cleaned and dressed.
3. Coupling ready to ship.	4. Coupling installed ready to be tested.

The Results Were:

• A very happy plant manager, when he learned that after (1) year of “down time” his compressor was finally back on line
• Almost (3) years later now, the unit is still running without any problems, and without
  any maintenance to the coupling.