Method and apparatus for working on workpieces with a water jet that contains abrasive and emerges under high pressure from a nozzle
View Patent ↗In a method for producing a water jet ( 45 ) that contains abrasive and emerges under high pressure from a nozzle ( 44 ), uninterrupted operation with, at the same time, greater working performance and lower costs is made possible in that, in a first step, an abrasive suspension ( 34 ) containing abrasive and water is provided at normal pressure, in a second step the provided abrasive suspension ( 34 ) is brought to a working pressure that is greatly above normal pressure, and in a third step a water jet ( 45 ) containing abrasive is produced, with a nozzle ( 44 ), from the abrasive suspension ( 34 ) that is under the working pressure.
1. A method for working on a workpiece with a water jet that contains abrasive and emerges under high pressure from a nozzle, the method comprising:
first providing an abrasive suspension containing abrasive and water at a first pressure;
second bringing the abrasive suspension to a working pressure above said first pressure;
third directly feeding the abrasive suspension under the working pressure to a nozzle; and
fourth issuing the abrasive suspension from the nozzle for acting on a workpiece surface.
2. The method as claimed in claim 1 , wherein providing an abrasive suspension comprises producing a mixture of water and abrasive in an open mixing vessel at said first pressure.
3. The method as claimed in claim 2 , wherein producing a mixture of water and abrasive comprises keeping the mixture in the mixing vessel continuously in motion.
4. The method as claimed in claim 3 , wherein keeping the mixture in motion comprises keeping the mixture in motion with an agitator.
5. The method as claimed in claim 1 , wherein bringing the abrasive suspension to a working pressure comprises bringing the abrasive suspension to a pressure of a plurality of MPa.
6. The method as claimed in claim 5 , wherein the working pressure is between 15 MPa and 25 MPa.
7. The method as claimed in claim 1 , wherein the abrasive has a hardness of at least 7 on the Mohs scale.
8. The method as claimed in claim 1 , wherein the abrasive comprises particles having a diameter in the range from 0.1 mm to 0.3 mm.
9. The method as claimed in claim 1 , wherein bringing the abrasive suspension to a working pressure comprises bringing the abrasive suspension to the working pressure with a pump, and further comprising:
routing the abrasive suspension at the working pressure from an output of the pump directly to the nozzle via a pressure line.
10. The method as claimed in claim 9 , wherein the pump comprises a diaphragm pump.
11. A water jet installation useful for executing a method as claimed in claim 1 , the water jet installation comprising:
a nozzle configured and arranged to produce a water jet;
a pressure line connected to the nozzle;
a pressure pump having an input side and an output connected to the pressure line to directly feed the abrasive suspension to the nozzle via the pressure line;
an intake line connected to the pump input side; and
a mixing vessel connected to the intake line, the mixing vessel containing the abrasive suspension.
12. The water jet installation as claimed in claim 11 , wherein the pump is a diaphragm pump.
13. The water jet installation as claimed in claim 11 , wherein:
the diaphragm pump has a diaphragm delimiting a pump chamber, an inlet valve connected between the intake line and the pump chamber, and an outlet valve connected to the pressure line; and
the inlet and outlet valves each comprise a valve sleeve having a central valve passage, a closing element, a valve seat on which the closing element rests, and a spring that biases the closing element opposite to the direction of flow, the closing element closing a downstream end of the valve passage.
14. The water jet installation as claimed in claim 13 , wherein:
the valve sleeve and the valve closing element are formed of a hard metal; and
the valve seats are ground-in.
15. The water jet installation as claimed in claim 14 , wherein the hard metal is tungsten carbide.
16. The water jet installation as claimed in claim 13 , wherein the closing element is ball-shaped in a region corresponding to the valve seat.
17. The water jet installation as claimed in claim 11 , further comprising:
a pressure relief valve in the pressure line.
18. The water jet installation as claimed in claim 11 , wherein:
the mixing vessel comprises an agitator with a motor; and
the mixing vessel comprises an open vessel.
19. The method as claimed in claim 1 , wherein said workpieces comprise power plant components.
20. The method as claimed in claim 19 , wherein said power plant components comprise boilers, heat exchangers, or turbines.
21. The method as claimed in claim 1 , wherein said first pressure is atmospheric pressure.