Patent ID: 7794215

Claim:
A slurry plunger pump assembly comprising: a. an inlet chamber connected to a slurry supply, said slurry comprised of a solid material and a slurry carrier fluid; b. a suction valve, downstream of said inlet chamber, for admitting, fluids and solid materials into a head end of a pump cavity; c. a plunger in said pump cavity for providing fluid movement and pressure; d. a means for driving said plunger through a suction and discharge stroke cycle; e. a seal mechanism attached at an opposed end of said pump cavity from said head end, contacting said plunger during movement; f. a discharge valve connected to said pump cavity for discharging pressurized materials from said pump cavity; g. a first clean fluid valve connected to a clean fluid supply, configured to supply clean fluid into the inlet chamber, upstream of the suction valve; and h. a second clean fluid valve mechanism connected to a clean fluid supply configured to provide clean fluid into said pump cavity near said seal mechanism at said opposed end of said cylinder wherein said second clean fluid valve mechanism is responsive to said plunger's position and direction in said pump cavity.