Any object on Earth can be cut open by a waterjet [come on], and diamonds, rails, bombs, piers, bulletproof glass are a piece of tofu in front of the waterjet. The sharpest "knife" in the world is the waterjet, which uses a high-pressure pump to pressurize the sealed water and spew it out through a spout made of sapphire and diamond, with a water pressure of up to 400MPa, which can cut any material, especially flammable and explosive dangerous goods.
Waterjet is also called water cutting, that is, high-pressure water jet cutting technology, through the pressure of water after the water as a knife, cutting objects technology. The earliest used in the aerospace industry, and later in the high-pressure water to add pomegranate sand, emery and other abrasives to assist cutting, improve the cutting speed and thickness, fast incision, flat incision, no dust, no thermal deformation, no pollution, reduce material waste.
The water pressure of waterjets is very high, usually 100MPa as the limit, below 100MPa for low pressure type, more than 100MPa for high pressure type, more than 200MPa for ultra-high pressure type, the current highest cutting pressure can reach 600MPa, the general commercial waterjet equipment pressure is about 200MPa -420MPa, the flow rate can reach 1000 meters / second, even the hardest diamond in nature can be cut.
Figure 2 is cutting an aerial bomb, which is a non-explosive aerial bomb left over from the World War II period, which contains 500 kilograms of TNT high-energy explosives, if an explosion occurs, there will be a serious disaster, so the scene with a water knife cut open the steel shell, TNT explosive layer, internal detonation pipe, because the water flow takes the high temperature away, so the cutting process will not cause an explosion, the same reason some grenades, mines, bombs, etc. can also be treated with water knife.
In the 1940s, the Americans invented the waterjet but the pressure is not large, the Soviets increased the pressure to 200MPa, can cut more objects, and later in the high-pressure water flow to increase emery, quartz sand and other abrasives, so that the waterjet can cut almost any hard object. At present, there are already three-axis, four-axis, five-axis robot waterjet cutting.
Later, it was found that when the water pressure exceeded a certain value, even pure water would detonate some sensitive chemicals, which was very dangerous, especially the cutting of sandy water, which had abrasive sand, and the huge impact of the sand collided with the cutting material, which would detonate some special chemicals. After many experiments, it was found that this threshold is about 237.6MPa, so when the water pressure is too high, it cannot be used for dangerous operations.
Because the pressure of the water is extremely high, so the nozzle of the waterjet must be made of cemented carbide, sapphire, diamond and other materials, the diameter of the nozzle is 0.05 mm, the inner wall of the nozzle is required to be smooth and flat, the maximum can withstand the pressure of 1700 megapascals, and the water can also be added to long-chain polymers in addition to Gaza, such as polyethylene oxide, so that the viscosity of high-pressure water is increased, and the water sprayed out is like a "thin line".
The heat generated when the waterjet is cut will be immediately taken away by the high-speed water flow, no harmful substances will be generated, the material is still cold, there will be no thermal effect, and the cutting process of any curve can also be realized. Therefore, in some dangerous areas, such as the opening of the top of the sewage settlement tank tank, the cutting of tank pipes in high-risk chemical industries, the cutting of coal mines in the case of high concentration gas, and the cutting of mine bombs.
How does the high pressure of 400MPa come about? Relying on the booster pump to pressurize the water, The low-pressure oil from the oil pump in Figure 6 pushes the plunger hydraulic cylinder reciprocating motion to pressurize the water. Then the pump beats the low-pressure water out, enters the supercharger to raise the water pressure, because the booster pump continuously produces high pressure, so it will cause the ejection of water flow instability, so these high-pressure water is stored in an energy storage tank, and then sprayed out of stable high-pressure water.
Fine particles such as emery can not be placed directly into the water pipe, because this will cause serious wear, as shown in Figure 5 is added at the nozzle, sapphire and ruby nozzle is very hard, is embedded in special metal materials, according to computer instructions on the cutting material to move, gem nozzle to form a jet of 3 times the speed of sound, accurate completion of the cutting operation. #人人能科普, there are new knowledge ## I do creation in the headlines ## Number one weekly magazine ##话题大发明家 #
