|Classification of Abrasive Water Jet Technology|
|Release time: 2015-8-31|
| Abrasive water jet cutting is a new type of water jet cutting technology developed rapidly in the 1980s. It is formed by adding abrasive in high pressure water jet. At present, most domestic abrasive water jet cutting technology for underwater structures is at the research stage. A number of foreign offshore engineering companies have already used this technology in a large number of offshore oil fields. Abrasive water jet technology can be divided into the following categories: |
1. The front and back mixed abrasive jets are divided into front mixed abrasive jets and back mixed abrasive jets according to the different ways of adding abrasives.
1) Pre-mixed abrasive jet The pre-mixed abrasive jet and the high-pressure water are initially mixed in the abrasive tank, in a pseudo-fluid state, and sent to the nozzle through a high-pressure hose. The front mixed abrasive jet improves the mixing mechanism of the abrasive and the water medium, and the working pressure is low.
2) Post-mixed abrasive jet. After-mixed abrasive jet cutting system, the abrasive mixing is completed inside the nozzle. Because the abrasive is added after the jet is formed, it is difficult to fully mix the abrasive with high-speed water. In order to obtain high-speed impact abrasive particles, the system operating pressure needs to be increased.
The abrasive of the front mixed abrasive jet is transported together with water through a high-pressure hose. There are serious pipeline wear and blockage problems in long-distance applications, and it is usually used in shallow water. The abrasive of the post-mixed abrasive jet is transported by an independent hose, which does not have the problem of high-pressure water pipe clogging or serious abrasion of the high-pressure water pipe. It is suitable for the operation of underwater cutting of steel structures, especially deep sea cutting.
2. External cutting and internal cutting are divided according to whether there is a solid wall surface in the operating environment. Water jets can be cut externally and internally.
1) External cutting Take the cutting of the tube structure as an example. The external cutting (cutting from the outside of the tube structure) is a free water jet.
2) When cutting internal components such as tube-shaped structures, the working environment is limited by solid walls, and is a non-free water jet, and it is a typical jet in the pipe.
Generally, internal cutting is preferred for pipe structures such as pile foundations, conduits, and casing strings of offshore oil platforms, because internal cutting does not require divers to launch into the water, so it usually becomes the owner's preferred method. However, internal cutting often makes visual monitoring difficult due to the action of soil, and other techniques are needed to monitor the cutting process.