Abstract: A downhole pump for a well has a barrel and a plunger. The barrel has a passage extending along the length of the barrel, with the passage having an inside diameter. The plunger has an outside diameter and is received by the barrel passage for relative reciprocal movement. One of the barrel or the plunger is equipped with wear rings, with a wear ring at one or at each end. The wear rings are made of a material that is harder than the material of the respective plunger or barrel. The wear rings provide protection from abrasion, particularly in a sandy well.

Abstract: A stuffing box for a polished rod used with a downhole pump uses injectable packing to provide a seal around the polished rod. The stuffing box has a chamber for receiving the packing. The chamber has an opening to allow the addition of packing to the chamber. The packing is maintained in a compacted condition by either injecting additional packing through the opening or adjusting the volume of the chamber.