The Soft-Start clutch from LC Tanks Inc. in Paducah, Ky., eliminates the “big bang” or harsh engagement caused when pumpers start their vacuum pressure blowers with manual or automatic transmissions.

With the clutch, the blower no longer requires high torque to start the blower lobes rotating. That, in turn, eliminates the noisy engagement when the blower starts, as well as the frequent replacement of coupling inserts, says LaVerne Charlet, owner of LC Tanks.

“Coupling inserts frequently need replacement,” Charlet says. “There’s an awful lot of force involved, so they shear easily. You can’t replace them without taking off the gearbox, which takes about two or three hours. Then you need to line it up properly – it’s difficult and time consuming.”

By minimizing torque spikes, the clutch also extends the life of the gearbox, coupling, and blower assembly.

“Before this, the only way you could have an automatic transmission was to install a hydraulic drive system, adding expense and weight,” Charlet says. “You also need a large oil reservoir to keep the hydraulic oil cool, which isn’t easy to do with the limited space available with the new truck emissions.”

Rated for 38 hp at 1,000 rpm and 300 hp at a maximum speed of 2,000 rpm, the clutch is capable of starting heavy inertia loads up to 800 pound-feet squared. It’s compatible with blowers that generate from 800 to 900 cfm.

The clutch mounts on the gearbox input shaft and is available with standard bores and keyways. The face is drilled and machined for standard 1350 SAE flange yokes to attach to the driveline. A U-joint and driveline absorbs any potential misalignment, Charlet says. This flange yoke is included with the clutch.

The clutch, which comes with a one-year warranty, weighs about 50 pounds and measures about 9 inches in diameter and 5 inches thick. They’re sold by LC Tanks, as well as National Vacuum Equipment Inc. (NVE) and Masport Inc.

For more information, call 888/848-3727 or send an e-mail to lctanks@bellsouth.net.