Patent ID: 7686598

Claim:
A downhole pump, comprising: a) a barrel having a first one-way valve; b) a plunger located in the barrel so that one of the plunger or the barrel reciprocates with respect to the other of the plunger or the barrel, the plunger having an interior passage therethrough, the plunger having a second one-way valve, the plunger and the barrel forming a compression chamber between the first and second one-way valves; c) the plunger having a first portion with a first seal with the barrel; d) the plunger having a second portion that forms a pressure balancing chamber between the barrel and the plunger, the plunger second portion having an opening so as to allow communication between the plunger interior passage and the balancing chamber; e) a wall located relative to the opening so as to form a sand snare chamber located in the balancing chamber, the wall coupled to the plunger; f) the plunger having a third portion, the plunger second portion being interposed between the plunger first and third portions, the plunger third portion having a second seal with the barrel.