I worked in your company a few years ago. If necessary, I can serve you.
I can explain the principle of underwater cutting.
According to the cutting principle, underwater cutting can be divided into three categories: underwater thermal cutting, underwater explosive cutting and underwater mechanical cutting. ?
Underwater cutting in 1802, some scholars pointed out that the arc can continue to burn underwater, that is, pointed out the possibility of underwater welding cutting. However, the actual application was after 100 years, when it was impossible to move the structure to land for welding, or it was too expensive. With the rapid development of marine science and technology and marine development, underwater welding and underwater cutting technology are more and more widely used.
Underwater cutting, cutting the workpiece in water. Underwater cutting is mainly used for salvage at sea and disintegration of nuclear pollution structure in water. With the maturity of technology, underwater cutting is gradually applied to underwater projects of various scales.
The underwater cutting gun used by divers in our company is BROCO underwater cutting gun BR-22, because its supporting equipment is simple and the requirements for operators are relatively low. BR-22 cutting gun is designed according to ergonomics, which makes divers comfortable and reduces forearm fatigue. The cutting gun is made of durable impact and corrosion resistant materials. All metal parts are brass. Non-conductive interference coupler connects oxygen control raft and cutting gun head, which is a key safety component with unique design and can only be found in Broco cutting gun. All joints are threaded and easy to maintain (provide a full set of spare parts). The sturdy flash eliminator has an internal filter to protect divers and cutting guns without obstructing the flow of oxygen. The big chuck nut is knurled to ensure that the diver holds it firmly. Trapezoidal threads contain sludge or other debris to ensure that the courier can reliably insert and hold the cutting rod. Interchangeable chuck can install 3/8 inch or 1/4 inch cutting rod. In addition, BR-22 can be used as an electrode fixer to fix the electrode. ? The produced BR-22 cutting gun can be used trouble-free for many years at the lowest cost. Use ultimate value. The cutting rod 38 18UW-25 of BR-22 underwater cutting gun is characterized by burning at the tip of the rod at a temperature exceeding 10000 degrees Fahrenheit. Broco's overheated cutting rod can cut or melt almost hot and known materials. Broco's patented cutting rod is characterized by the core wire of several-day alloy, which is fixed by a series of round pleated fabrics. The alloy wire of the cutting rod is sunken at one end of the cutting gun, which helps to prevent the combustion products from flowing back to the cutting gun, making Broco underwater overheating cutting rod the safest product on the market. Overheated cutting rods can be bent 90 degrees or more to get into hard-to-reach places without blocking oxygen flow or causing insulation to crack or peel off. Although they can be used for the maximum current of 150 ampere, the overheating cutting rod has no electrical equipment. Once ignited, as long as there is oxygen supply, they will continue to burn until they are consumed. ? Broco's underwater overheating cutting rod is available in two diameters of 1/4 inch and 3/8 inch to meet the diver's working requirements. The standard length is 18 inch. For a huge cutting task, the 3/8 "*36" overheated cutting rod can be further extended, and it takes longer to replace the cutting rod. It will be safer, faster and cheaper to cut, punch or cut underwater with Broco's underwater overheating cutting stick.
Operating specifications for underwater cutting guns:
1. Pay attention to the current and voltage-the human body has certain resistance to the passing current, but when the current reaches a certain limit, it will make people feel pain and endanger their lives. The so-called safe current passing through the human body refers to the limit value of current passing through the human body without causing danger to people. The safety current varies from person to person, and the types of current are different, so are the safety currents. Direct current is safer than alternating current: when the human body passes through 60 ~ 90 mA direct current, it will bring serious consequences; However, when 15 ~ 23 mA alternating current is applied, it will cause serious consequences. Therefore, AC power supply is not suitable for underwater cutting, nor for control circuit or lighting circuit. The current passing through the human body depends on the voltage of the human body contacting the charged body and the contact resistance of the human body. Safe voltage refers to the voltage limit to ensure that the current passing through the human body does not exceed the safe current. When the human body is in water, especially in seawater, the contact resistance of the human body is obviously reduced, and the safe voltage it can bear is also reduced. In addition, the resistance of the human body is also affected by the voltage itself. With the increase of contact voltage, the resistance of human body decreases gradually, the safety current and safe voltage of human body vary from person to person, and the safety current and safe voltage of the same person under different conditions are also different, so it is not easy to determine an exact value. China's national standard "Underwater Welding and Cutting Safety" stipulates that all control appliances in direct contact with divers must use isolation transformers and be equipped with overload protection facilities. Safe voltage value: power frequency alternating current does not exceed 12V, and direct current does not exceed 36V. The above safe voltage value refers to the voltage value that directly touches the human body, and the actual cutting power supply voltage used in underwater cutting is mostly around 80V (DC), which is much higher than the safe voltage value, but it is safe as long as it does not directly touch the human body.
2. Measures to prevent underwater electric shock Before construction, divers should be educated on safe electricity use, understand and master the knowledge of safe electricity use, and improve their ideological understanding. ? Check the insulation and watertightness of electrical equipment for underwater cutting, and replace or repair it in time if it does not meet the requirements. ? Divers who cut underwater should wear waterproof and insulating gloves, keep their hands dry, and do not directly contact charged bodies. ? In the process of underwater cutting, if it is necessary to replace the cutting strip or cut the wire, the water staff should be informed to cut off the power supply first.
This is my experience in underwater cutting for many years. If necessary, we can serve you.