Machine Design
Electric pump built for torquing

Electric pump built for torquing

The portable TQ-700 electric pump from Enerpac, Menomonee Falls, Wis. sends pressurized hydraulic fluid to wrenches, letting them tighten bolts. Once plugged in, a 1-hp brushless induction motor turns a pump which pressurizes the fluid and sends it to the tool via hoses. The fluid then powers the reciprocating force that turns the cassette hex or impact socket wrench.

The motor draws few amps, so it won’t slow when running on a field generator’s variable voltage. The motor tolerates high voltages, which prevents it from burning out due to voltage spikes or drops caused by long extension cords. In operation, the low-maintenance motor and pump generate 82 to 85 dBA.

The pump can install bolts in less than half the time of traditional torque-wrench pumps. In a 1-hr test, the TQ-700 tightened 612 bolts (14 × 17/8 in.) versus 322 bolts for a conventional pump.

Much of that speed is attributed to the unit’s three separate oil-flow stages. During the first stage when free-turning the nut onto a stud, oil flow is high. Stage two kicks in as the stud starts to elongate and nut rotation decreases. In this stage, the pump generates more work than a two-stage pump as pressure increases while reducing the amount of heat generated. This cooler operation results in longer pump life. The third stage comes into play when rotation slows even more and lasts until the nut tightens to the proper torque. Overall, more work is done and less heat is wasted while working faster and extending the life of the unit.

The unit operates in temperatures from –4 to 122°F and is rated for 10,000-psi (700-bar) operation. There’s also a 20-ft cord on a pendant with remote motor controls, so the worker controlling the pump can move around the work site. An optional manifold sends power to up to four wrenches at the same time.

The pump is equipped with a roll cage and side panels for extra protection, and the built-in handle also functions as a hoisting point. The 4-in. pressure gage on the pump is protected by a polycarbonate shield. The small, 66‑lb (dry) pump is sized to fit through small wind-turbine door hatches, so it is well suited for turbine installation and maintenance, as well as factory floor or work site applications.

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