Recirculation of wet abrasive material in abrasive waterjet systems and related technology

1. A method for operating an abrasive waterjet system, the method comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes abrasive material to become entrained in the jet;

impacting the jet against a workpiece to alter the workpiece;

diffusing the jet in a catcher of the abrasive waterjet system;

collecting slurry including abrasive material and liquid from the catcher;

automatically decreasing a rate of movement of the cutting head at least partially in response to an increased fraction of spent abrasive material in the slurry collected from the catcher; and

flowing the slurry collected from the catcher into the mixing chamber.

2. The method of claim 1 wherein flowing the slurry collected from the catcher into the mixing chamber includes drawing the slurry into the mixing chamber at least partially by the Venturi effect.

3. The method of claim 1 wherein supplying pressurized liquid to the jet-forming orifice includes supplying all or most of a total supply of pressurized liquid to the jet-forming orifice at a pressure of at most 15,000 psi.

4. The method of claim 1 , further comprising screening large particles of kerf material from abrasive material within the catcher.

5. The method of claim 1 , further comprising screening large particles of kerf material from abrasive material collected from the catcher.

6. The method of claim 1 , further comprising, at a fines separator of the abrasive waterjet system, removing fines from the slurry collected from the catcher, wherein flowing the slurry collected from the catcher into the mixing chamber includes flowing the slurry into the mixing chamber via the fines separator.

7. The method of claim 6 wherein removing fines from the slurry collected from the catcher includes removing fines at least partially by operation of a hydrocyclone.

8. The method of claim 1 , further comprising storing abrasive collected from the catcher in a holding tank of the waterjet system.

9. The method of claim 8 , further comprising agitating the stored abrasive material in the holding tank.

10. A method of for operating an abrasive waterjet system, further the method comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes abrasive material to become entrained in the impacting the jet against a workpiece to alter the workpiece;

diffusing the jet in a catcher of the abrasive waterjet system;

collecting slurry including abrasive material and liquid from the catcher;

flowing the slurry collected from the catcher into the mixing chamber; and

automatically decreasing a rate of movement of the cutting head to at least partially compensate for an increased fraction of spent abrasive material in the slurry flowing into the mixing chamber.

11. The method of claim 10 wherein the cutting head is configured to move relative to the workpiece through a predetermined sequence of movements, and wherein automatically decreasing the rate of movement of the cutting head includes automatically decreasing the rate of movement of the cutting head through the predetermined sequence of movements.

12. The method of claim 10 wherein flowing the slurry collected from the catcher into the mixing chamber includes drawing the slurry into the mixing chamber at least partially by the Venturi effect.

13. The method of claim 10 further comprising, at a fines separator of the abrasive waterjet system, removing fines from the slurry collected from the catcher, wherein flowing the slurry collected from the catcher into the mixing chamber includes flowing the slurry into the mixing chamber via the fines separator.

14. A method for operating an abrasive waterjet system, the method further comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes abrasive material to become entrained in the impacting the jet against a workpiece to alter the workpiece;

diffusing the jet in a catcher of the abrasive waterjet system;

collecting slurry including abrasive material and liquid from the catcher;

flowing the slurry collected from the catcher into the mixing chamber;

detecting a concentration of abrasive material in the slurry collected from the catcher; and

automatically adjusting a rate of movement of the cutting head at least partially in response to the detected concentration.

15. The method of claim 14 wherein automatically adjusting the rate of movement of the cutting head includes automatically decreasing the rate of movement of the cutting head.

16. The method of claim 14 wherein the cutting head is configured to move relative to the workpiece through a predetermined sequence of movements, and wherein automatically adjusting the rate of movement of the cutting head includes automatically adjusting the rate of movement of the cutting head through the predetermined sequence of movements.

17. The method of claim 14 wherein supplying pressurized liquid to the jet-forming orifice includes supplying all or most of a total supply of pressurized liquid to the jet-forming orifice at a pressure of at most 120,000 psi.

18. The method of claim 1 , further comprising:

detecting a concentration of abrasive material in the slurry collected from the catcher; and

automatically adjusting a flowrate of the slurry flowing into the mixing chamber at least partially in response to the detected concentration.

19. The A method for operating an abrasive waterjet system, the method comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes abrasive material to become entrained in the impacting the jet against a workpiece to alter the workpiece;

diffusing the jet in a catcher of the abrasive waterjet system;

collecting slurry including abrasive material and liquid from the catcher;

flowing the slurry collected from the catcher into the mixing chamber; and

fluidizing abrasive material within the catcher,

wherein collecting slurry from the catcher includes collecting slurry including fluidized abrasive material from the catcher.

20. The method of claim 19 wherein:

flowing the slurry collected from the catcher into the mixing chamber includes flowing the slurry via a conveyance of the abrasive waterjet system;

fluidizing the abrasive material includes flowing fluidizing liquid toward the abrasive material at a fluidizer of the abrasive waterjet system; and

the method further comprises—

increasing a flowrate of the fluidizing liquid flowing toward the abrasive material at the fluidizer to flush the conveyance with the fluidizing liquid, and

ceasing forming the jet after increasing the flowrate of the fluidizing liquid.

21. The method of claim 20 , further comprising:

recharging the conveyance with slurry including fluidized abrasive material from the catcher after ceasing forming the jet; and

resuming impacting the jet against the workpiece after recharging the conveyance with the slurry.

22. The method of claim 19 , further comprising settling abrasive material within a lower portion of the catcher by gravity, wherein a transverse cross-sectional area of the lower portion of the catcher decreases at successively lower elevations, and wherein fluidizing abrasive material includes fluidizing the settled abrasive material within the catcher.

23. The method of claim 19 wherein:

fluidizing abrasive material includes fluidizing abrasive material at a fluidizer of the abrasive waterjet system; and

collecting slurry includes collecting slurry via a slurry port of the fluidizer, wherein the fluidizer includes a manifold extending at least partially around a perimeter of the slurry port.

24. The method of claim 23 wherein the slurry port is at a lower portion of the catcher, and wherein the method further comprises flowing liquid from an upper portion of the catcher to the lower portion of the catcher via the manifold.

25. The method of claim 1 , further comprising:

ceasing forming the jet;

removing at least a portion of the spent abrasive material from the catcher while the jet is ceased;

adding fresh abrasive material to the catcher while the jet is ceased; and

resuming forming the jet after adding fresh abrasive material to the catcher.

26. The method of claim 25 , further comprising automatically detecting a decreased cutting power of the jet, wherein ceasing forming the jet includes ceasing forming the jet at least partially in response to detecting the decreased cutting power.

27. A method for operating an abrasive waterjet system, the method comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes the abrasive material to become entrained in the jet; and

recycling the entrained abrasive material through a substantially closed-loop circuit including the mixing chamber, a catcher of the abrasive waterjet system, and a conveyance of the abrasive waterjet system, wherein the conveyance is configured to carry slurry including abrasive material and liquid collected from the catcher toward the cutting head; and

automatically decreasing a rate of movement of the cutting head at least partially in response to an increased fraction of spent abrasive material in the slurry collected from the catcher.

28. A method for operating an abrasive waterjet system, the method, comprising:

supplying pressurized liquid to a jet-forming orifice of a cutting head of the abrasive waterjet system;

forming a jet from the pressurized liquid at the jet-forming orifice;

passing the jet through a mixing chamber of the cutting head while the mixing chamber contains slurry including abrasive material and liquid, wherein passing the jet through the mixing chamber causes the abrasive material to become entrained in the jet; and

recycling the entrained abrasive material through a substantially closed-loop circuit including the mixing chamber, a catcher of the abrasive waterjet system, and a conveyance of the abrasive waterjet system, wherein the conveyance is configured to carry slurry collected from the catcher toward the cutting head;

adding fresh abrasive material to the catcher; and

passing at least 90% by weight of the added fresh abrasive material through the circuit at least twice.

29. The method of claim 28 wherein adding fresh abrasive material to the catcher includes adding fresh abrasive material to the catcher batchwise.

30. The method of claim 28 wherein adding fresh abrasive material to the catcher includes adding fresh abrasive material to the catcher continuously or semi-continuously.

31. The method of claim 27 wherein the cutting head is configured to move through a predetermined sequence of movements, and wherein automatically decreasing the rate of movement of the cutting head includes automatically decreasing the rate of movement of the cutting head through the predetermined sequence of movements.

32. The method of claim 27 wherein supplying pressurized liquid to the jet-forming orifice includes supplying all or most of a total supply of pressurized liquid to the jet-forming orifice at a pressure of at most 120,000 psi.

33. The method of claim 27 , further comprising:

screening large particles of kerf material from abrasive material collected from the catcher; and

at a fines separator of the abrasive waterjet system, removing fines from the slurry collected from the catcher, wherein carrying the slurry collected from the catcher toward the cutting head includes flowing the slurry into the mixing chamber via the fines separator.