Well service pump systems having offset wrist pins

A system of pumps for use in servicing wells, comprising:

• a) a first pump and a second pump;
• b) each of the first and second pumps comprising:
• i) a housing having a cylinder which has a cylinder axis, the housing having a first end and a second end;
• ii) a plunger having a crosshead that is reciprocally carried in the cylinder for movement between a suction stroke and an exhaust stroke;
• iii) a manifold mounted to the second end of the housing and being adjacent to the cylinder for supplying and delivering liquid acted on by the plunger;
• iv) a crankshaft mounted rotatably in the housing and having a crankshaft axis that is perpendicular to the cylinder axis;
• v) a connecting rod having a crankshaft end that is connected to the crankshaft and a crosshead end that is connected to the crosshead of the plunger by way of a wrist pin for reciprocating the plunger in response to the rotation of the crankshaft, the crankshaft end having a center line;
• vi) the crankshaft axis being coplanar with the cylinder axis while the wrist pin of the connecting rod is offset from the cylinder axis;
• c) the first and second pumps being arranged together so that the first end of the first pump housing is adjacent to the first end of the second pump housing;
• d) the first pump has the first pump wrist pin located offset in a first direction from the first pump cylinder axis such that as the first pump plunger moves through its exhaust stroke the crankshaft end of the first pump connecting rod is located on the same side of the first pump cylinder axis as the first pump wrist pin;
• while the second pump has the second pump wrist pin located offset in a second direction from the second pump cylinder axis such that as the second pump plunger moves though its exhaust stroke the crankshaft end of the second pump connecting rod is located on the same side of the second pump cylinder axis as the second pump wrist pin.