Fewer Rod Failures

Rod parts dramatically decline as rod buckle is reduced. As the SPM's are reduced, the plunger is allowed time to fall instead of being forced downward by the weight of the rods. The traveling ball/cage assembly is given more time for fluid to pass through this congested area, thus pressure drop across the valve is reduced substantially.
The physical weight of the rod string is the only mechanical force pushing the plunger back through the fluid on the down stroke. Rod buckle is caused when the plunger resists this downward movement. Downward movement is impeded by the inability of the traveling ball/cage assembly to allow the fluid to pass by as quickly as is required by high SPM.

When the rod string experiences this resistance to fall, the total rod string weight is supported by the first few rods above the pump. Additionally, if it is necessary to tag bottom, more compression is added to this bad situation.

Applications with low production and high SPM experience a high degree of rod parts deep in the hole.

Rapid fluid movement past the traveling valve ball at high SPM causes the ball to rattle around wildly in the cage thus causing a greatly reduced service life.
At higher SPM a case may exist where the rods and the plunger are still failing when the surface equipment has already started the upstroke. This results in a tremendous force applied to the rod pins and boxes when they snap tight.

This situation results in the bottom hole stroke length being substantially shorter than the surface stroke length.

Longer rod life!

A rod string with the life cycle of 15MM cycles @ 9 SPM
has a 3.17 year run time.

With Slow Jack™

and a reduction to 3 SPM
the life span would increase to 9.51 years!