A power end includes a monolithic core with a base having a surface configured to mount to a fluid end of the reciprocating pump and a plurality of extensions integral to the base. Each extension of the plurality of extensions includes a ring portion that defines an opening configured to receive a crankshaft of the reciprocating pump. The power end also includes a plurality of plates separate from the monolithic core. Each plate of the plurality of plates extends between a pair of adjacent of extensions of the plurality of extensions to enclose the monolithic core.

A power end includes a monolithic core with a base having a surface configured to mount to a fluid end of the reciprocating pump and a plurality of extensions integral to the base. Each extension of the plurality of extensions includes a ring portion that defines an opening configured to receive a crankshaft of the reciprocating pump. The power end also includes a plurality of plates separate from the monolithic core. Each plate of the plurality of plates extends between a pair of adjacent of extensions of the plurality of extensions to enclose the monolithic core.

The invention relates to a fluid compression apparatus and method comprising first and second compression chambers, an intake system into the first chamber, a transfer system from the first chamber to the second chamber, a piston for ensuring the compression of the fluid in the first and second chambers, and an orifice for discharging the compressed fluid, the intake system comprising one or more valves, the apparatus further comprising a discharge orifice allowing communication between the first compression chamber and the bath to allow surplus liquid trapped in the first compression chamber to leave during a compression movement of the piston in the first compression chamber, the apparatus comprising a discharge valve configured to control the discharge of liquid via the discharge orifice and to prevent fluid from entering the compression chamber via the discharge orifice.