Advancements in pump configurations improve pump life in the oil patch.
by Rob Giese, Quadna, a DXP Company
March 28, 2013

Well-equipped and versatile vacuum trucks are critical to all oil and gas operations. Vacuum trucks are tank trucks that feature a heavy-duty vacuum system designed to use vacuum technology to load liquids, sludge or slurry through suction lines. These pumps are also used to unload tanker trucks using pressure. Many different types of vacuum pumps are available, and the type chosen depends on the geographic location and the application’s specifications.

Configurations of Vacuum Pumps

Some vacuum pump configurations are V-belt, gearbox, hydraulic and engine. In these configurations, the pumps can be water or air cooled. In colder climates, water-cooled (or heated) pumps are used. When using a pump in vacuum mode, it sucks in moisture. When shut off, the moisture condenses on the bottom of the pump. If left to freeze, the pump’s vanes can break off—which is why using heated water is important to ensure that the water cannot freeze.

A vacuum pump (on a tanker) with a hydraulic driveA vacuum pump (on a tanker) with a hydraulic drive

Most vacuum pumps are driven off a semi truck’s power takeoff (PTO) instead of off a stand-alone engine. The two truck types that are best suited for these installations are the bobtail, which has an 80-barrel capacity, and the transport, which features a 130-barrel capacity.

A vacuum truck’s pulley system should house a PTO, drive shaft, two pillow block bearings, two sheaves and three to four belts at a minimum. The gearbox system should have a PTO, drive shaft, right-angle gearbox and coupling. A hydraulic system should contain a PTO, hydraulic motor, hydraulic pump motor housing and coupling, and a hydraulic oil cooler with a fan. For many applications, the hydraulic system configuration is the optimal arrangement.

An 80-barrel tanker with a vacuum pumpAn 80-barrel tanker with a vacuum pump

The engine system is used only when no truck PTO is available. Gas or diesel engines are the best drive choice for applications with a belt or gearbox set up.

Oilfield Operations

The vacuum pump industry has changed drastically through the years. Previously, vacuum trucks were used primarily by the sewer and septic industry. Today, they are used in oilfields throughout the country.

A vacuum pump on a tankerA vacuum pump on a tanker

Vacuum pumps were first used for the disposal of produced water and water from hydraulic fracturing operations in the oilfield. Typically, these pumps were in a belt pulley system configuration consisting of a PTO, drive line, pillow block and sheaves to power the pump. This system added wear to the pump’s bearing because of the tension of the belts required, which caused excessive wear and early pump component failure.

As technology changed, the gearbox system was introduced. This system used a drive line, right-angle gear box and coupler to power the unit. This advanced tank technology increased the life of the pump because of the direct, inline coupling of the pump and gearbox, creating less lateral wear to the bearings from excessive belt tension.

The next improvement was upgrading to a hydraulic power system. This system featured a hydraulic pump, hydraulic motor, coupling bracket and coupling. The advantage of the hydraulic system was that no alignment issues existed because everything was a registered fit between the hydraulic motor and the pump.

Conclusion

During the past seven years, one pump company has converted hydraulic systems for more than five major production and disposal companies in the western region of the U.S. that serve the oil and gas industry. These systems have created more revenue and less downtime resulting in greater profits for the end users.

The cost for the conversion is roughly 25 to 30 percent higher than the the cost of traditional configurations, and the improvements to operations are significant.