Apparatus and method for waterjet cutting

Abstract

Disclosed is an apparatus for water jet cutting including: a water source; a pump communicating with the water source, generating a high pressure water flow; a tank containing an abrasive material in suspension, including a fluid and abrasive particles dispersed homogeneously in the fluid; and a cutting head in fluid communication with the pump and the tank, the cutting head including a mixing chamber. The tank of the abrasive material in suspension is in communication with the cutting head by an abrasive inlet channel and the cutting head is configured to generate a vacuum pressure that draws the abrasive material in suspension through the abrasive inlet channel toward the mixing chamber to mix the abrasive material in suspension and the high pressure water and form a jet of water and abrasive. Also disclosed is a method for generating a water jet cut that can be implemented with the apparatus.

1 . Apparatus ( 1 ) for water jet cutting comprising:
 a water source ( 2 );   pumping means ( 4 ), in communication with the water source, to generate a high pressure water flow;   a tank ( 22 ) containing an abrasive material in suspension ( 21 ), wherein said abrasive material in suspension comprises a fluid and abrasive particles dispersed homogeneously in the aforesaid fluid; and   a cutting head ( 10 ) in fluid communication with said pumping means ( 4 ) and said tank ( 22 ), said cutting head comprising a mixing chamber ( 12 );   
       wherein said tank ( 22 ) is in communication with said cutting head ( 10 ) by means of an abrasive inlet channel ( 23 ) and said cutting head ( 10 ) is configured to generate a vacuum pressure that draws the abrasive material in suspension ( 21 ) through said abrasive inlet channel ( 23 ) toward the mixing chamber ( 12 ) to mix the abrasive material in suspension and the high pressure water and form a jet of water and abrasive substance ( 15 ). 
     
     
         2 . Apparatus ( 1 ) according to  claim 1 , wherein the abrasive inlet channel ( 23 ) is equipped with flow regulating means ( 27 ) of the abrasive material in suspension ( 21 ). 
     
     
         3 . Apparatus ( 1 ) according to  claim 1 , wherein said abrasive material in suspension ( 21 ) comprises abrasive particles dispersed in a gelatinous substance. 
     
     
         4 . Apparatus ( 1 ) according to  claim 3 , wherein said gelatinous substance comprises at least water and a gelling agent. 
     
     
         5 . Apparatus ( 1 ) according to  claim 3 , wherein the volume ratio between the abrasive particles and the gelatinous substance is from 1:4 to 1:8. 
     
     
         6 . Apparatus ( 1 ), according to  claim 4 , wherein the volume percentage of the gelling agent in the water is between 0.5% and 5%. 
     
     
         7 . Apparatus ( 1 ) according to  claim 1 , wherein said cutting head ( 10 ) comprises a focusing tube ( 14 ) of the jet with a diameter between 0.4 mm and 1.5 mm, and a length between 100 mm and 200 mm. 
     
     
         8 . Apparatus ( 1 ) according to  claim 1 , wherein at said cutting head ( 10 ) comprises a focusing tube ( 14 ) that includes at least two portions of tube joined by a removable connection element. 
     
     
         9 . Apparatus ( 1 ) according to  claim 2 , wherein said flow regulating means ( 27 ) are mounted at an outlet of the abrasive material of said tank ( 22 ). 
     
     
         10 . Apparatus ( 1 ) according to  claim 9 , wherein said flow regulating means ( 27 ) comprise an opening, through which the abrasive material in suspension can flow, and a moving partition, associated with control means, adapted to obstruct or partly or totally free the aforesaid opening. 
     
     
         11 . Apparatus ( 1 ) according to  claim 3 , further comprising a mixing device ( 24 ) to mix the water, the gelling agent and the particles of abrasive material to form the abrasive material in suspension ( 21 ). 
     
     
         12 . Apparatus ( 1 ) according to  claim 11 , further comprising dosing means ( 26 ), associated with said mixing device ( 24 ), to dose the quantity of water, of gelling agent and of particles of abrasive material to form the abrasive material in suspension ( 21 ). 
     
     
         13 . Apparatus ( 1 ) according to  claim 1 , further comprising:
 a collection container ( 31 ) to collect the water and the abrasive material, delivered from the cutting head ( 10 ), and the waste material from processing;   a recovery and recycling system ( 30 ) that includes at least:
 separation means ( 33 ) to separate reusable wet abrasive particles from non-reusable wet abrasive particles and from waste material; and 
 transport means to transfer said wet mass of reusable abrasive particles into the tank ( 22 ) of the abrasive material in suspension or into the mixing device ( 24 ). 
   
     
     
         14 . Method for generating a water jet cut with a cutting apparatus, comprising the following steps:
 providing a water source ( 2 );   preparing an abrasive material in suspension ( 21 ), this latter comprising a fluid and abrasive particles dispersed homogeneously in the aforesaid fluid;   pumping the water at high pressure into a mixing chamber ( 12 ) of a cutting head ( 10 );   generating a vacuum pressure in the mixing chamber ( 12 ) to draw the abrasive material in suspension ( 21 ) into said mixing chamber ( 12 ) through an abrasive inlet channel ( 23 );   mixing, in said mixing chamber ( 12 ), the pressurized water and the abrasive material in suspension ( 21 ); and   discharging a jet of water and abrasive material ( 15 ) from a focusing tube ( 14 ) in communication with the mixing chamber ( 12 ).   
     
     
         15 . Method according to  claim 14 , wherein the step of preparing the abrasive material in suspension ( 21 ) comprises the stage of mixing the fluid and the abrasive particles. 
     
     
         16 . Method according to  claim 14 , wherein the fluid is a gelatinous substance. 
     
     
         17 . Method according to  claim 16 , wherein the step of preparing the abrasive material in suspension ( 21 ) comprises the stage of mixing water, at least one gelling agent and particles of abrasive to form said gelatinous substance in which the particles of abrasive are suspended and dispersed homogeneously. 
     
     
         18 . Method according to  claim 15 , wherein the step of preparing the abrasive material in suspension ( 21 ) comprises a further stage, preceding the mixing stage, consisting of dosing the fluid and the abrasive particles. 
     
     
         19 . Method according to  claim 17 , wherein the step of preparing the abrasive material in suspension ( 21 ) comprises a further stage, preceding the mixing stage, consisting of dosing the water, the gelling agent and the abrasive particles. 
     
     
         20 . Method according to  claim 15 , wherein the mixing step is carried out in a mixing device ( 24 ), said abrasive material in suspension ( 21 ) prepared being subsequently conveyed into a tank ( 22 ) in fluid communication with the mixing chamber ( 12 ). 
     
     
         21 . Method according to  claim 14 , comprising the following steps:
 collecting at least a part of the jet of water and abrasive delivered from the cutting head ( 10 ) in a collection container ( 31 );   separating reusable wet abrasive particles from non-reusable wet abrasive particles and from waste material;   transferring said wet mass of reusable abrasive particles into a tank ( 22 ) of the abrasive material in suspension or into a mixing device.   
     
     
         22 . Method according to  claim 21 , wherein the step of preparing the abrasive material in suspension comprises the mixing of water, at least one gelling agent, said abrasive particles, wet or dry, or of both types.