An adapter for coupling between a rod and a plunger in a downhole pump system, said adapter comprising:
- a shaft having an axial through-bore passing axially therethrough from a top end of the shaft to an opposing bottom end thereof, and being configured at an upper coupling portion for coupled attachment to a first component of the downhole pump system of uphole relation to the adapter;
- a cup having a chambered upper portion spanning circumferentially around the shaft at a neck portion thereof that resides below said upper coupling portion and inside a hollow upper chamber of the chambered upper portion of the cup, said hollow upper chamber being open at a top end of the cup and having an internal diameter that exceeds an external diameter of the neck portion of the shaft, thereby leaving an open sand trap annulus between the shaft and the cup at the chambered upper portion thereof;
- one or more sand trap ports penetrating a peripheral wall of the shaft at the neck portion thereof and thereby fluidly communicating the axial through-bore of the shaft with the open sand trap annulus between the shaft and the cup at chambered upper portion thereof;
- a sand trap shoulder provided on the shaft at a location thereon above both the neck portion of the shaft and the upper chambered portion of the cup, said sand trap shoulder spanning circumferentially around the shaft and imparting a localized increase of external diameter to the shaft relative to neighbouring areas thereof immediately above and below the sand trap shoulder to hinder passage of sand, situated outside the shaft, from above the sand strap shoulder downwardly therepast toward the plunger;
- and
- angled cleanout ports penetrating an exterior of the peripheral wall of the shaft just above the sand trap shoulder and penetrating an interior of the peripheral wall, into the axial through bore of the shaft, at lesser elevation thereon than where the angled cleanout ports penetrate the exterior of the exterior of the peripheral wall, said angled cleanout ports being operable to flush clean the sand trap shoulder during a downstroke of the downhole pump system;
- wherein an outer diameter of the sand trap shoulder of the shaft is less than an outer diameter of the cup so that the sand trap shoulder denotes a partial sand trap effective to capture a first fractional portion of said sand, while permitting a second fractional portion of said sand to pass downwardly past the sand trap shoulder to the cup, where the second fractional portion of said sand capturable by the sand trap annulus at the chambered upper portion of the cup, whereby the sand trap and the cup cooperatively inhibit downward passage of sand to the plunger.