Ruined parts
The blue object is a plastic coated rod coupling. Above it, in the
half pipe, is a similar coupling which has had its coating worn off due to the friction of
rotation in the midst of produced sand.
A worn rod coupling will allow the rod to rotate off centre, perhaps
even against the wall of the tubing. Both pieces of tubing (3rd and 6th from left)
display this type of damage, called "wire marks"
The other type of damage shown here is to stators ( the stationary
housing of a rotating progressive cavity pump) The constant rotation accompanied by
sand in production can line and gouge the interior of the stator. A dramatic example
is shown 2nd from left where pyrite from the formation has entered the stator and the
friction has ground away the elastomer lining and deeply grooved the interior metal wall
of the stator and produced pyrite balls
