Packing retaining component for a fluid pump

A fluid end of a fluid pump, comprising

• a fluid end block with a bore in which a plunger is to reciprocate;
• a valve cartridge, configured for insertion into and removal from the bore as a unit, comprising:
• a valve cartridge housing having an open end;
• and
• a plurality of valves operably connected to the valve cartridge housing;
• and
• a packing retaining component with a plunger bore, to receive the plunger, that defines a first open end and a second open end of the packing retaining component,
• wherein the valve cartridge housing and the packing retaining component are engaged such that the open end of the valve cartridge housing and the first open end of the packing retaining component overlap.

A fluid end of a fluid pump, comprising:

• a fluid end block with a bore in which a plunger is to reciprocate;
• a valve cartridge, configured for insertion into and removal from the bore as a unit, comprising a valve cartridge housing having an open end, and a plurality of valves operably connected to the valve cartridge housing;
• and
• a packing cartridge, configured for insertion into and removal from the bore as a unit, comprising a packing cartridge housing having a plunger bore, to receive the plunger, that defines a first open end and a second open end of the packing cartridge housing,
• wherein an interface between the valve cartridge housing and the packing cartridge housing is fluid tight to isolate a portion of the fluid end block, along the plunger bore, from cyclic pressure in the fluid end, wherein the valve cartridge housing and the packing cartridge housing are engaged such that the open end of the valve cartridge housing and the first open end of the packing cartridge housing overlap.