PEAK ToRQUE The work transmitted from the prime mover through the gear reducer and crank applies a torque to the gears. Gear reducers are rated by the peak torque they can carry on a continuous basis. The peak torque T in inch-pounds (newton-meters) is proportional to the load range and may be calculated from the formula

The calculated peak torque must be lower than the torque rating, and the calculated peak polished rod load must be lower than the structure capacity rating of the unit selected (Table 3).

POLISHED rod power The polished rod power Ppr in horsepower (kilowatts) can be calculated from the formula

Because the polished rod power calculation does not take friction into account, the prime mover selected should have at least double the power of the calculated figure.

plunger Overtravel In accurately calculating pump displacement, it is necessary to calculate the actual plunger stroke, which is not the same as the polished rod stroke. The plunger gains stroke from overtravel. Long strings of rods are elastic and capable of stretching several feet. When the pumping unit stops the polished rod at the bottom of the surface stroke, the plunger continues to move downward because of inertia. This plunger overtravel OT in inches (meters) can be calculated from the formula

TABLE 5 External upset tubing data


Survival Treasure

Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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