VNIINM is developing an underwater laser cutting complex

- when cutting metal under water is used

— technologies for underwater cutting of metals

- how to cut underwater using gasoline

— oxygen and electric underwater cutting of metal

— performing work using an electric arc

— work with a cutter to which a gas mixture with oxygen is supplied

— exothermic electrodes for welding and cutting under water

— characteristics of exothermic electrodes

— video of using equipment at great depths

The demand for underwater cutting of metal and other structures is beyond doubt. This is an economical and most rational way that allows you to work with objects of various sizes. Equipment for performing operations in water is constantly being improved, as are technologies, which become more efficient and safer every year.

Underwater metal cutting: description of the technological process

Underwater metal cutting is used in rescue, construction and ship-lifting operations.
For underwater work, electric-oxygen and gas cutting methods are used. The electro-oxygen cutting method is more dangerous from a safety point of view due to the possibility of electric shock, especially in sea water.

Underwater cutting of metal with a cutter is carried out mainly with cutters running on gasoline, because such a flammable substance can be fed to a considerable depth under high pressure. Acetylene can explode at high pressures, so it is not used. The power of the preheating flame for underwater cutting is 10-15 times higher than the power of the flame for cutting in air.

The fire burns underwater in a gas bubble created by combustion products of gasoline, or by pumping air around the cutter head to push the water out. The flame is ignited by an electric igniter that is connected to a battery. The pressure in gasoline tanks is created by nitrogen. In cutters, gasoline is sprayed into the swirl heads and evaporates.

For underwater cutting, a special BUPR installation is widely used. The oxygen cylinder ramp, fuel canister, nitrogen cylinders and the BUPR control panel must be placed above the water. Excessive gasoline can float to the surface of the water, which is why oxy-fuel cutting is used in shallow reservoirs and confined spaces.

Hydrogen cutting of metal is carried out using hydrogen, which is produced in the apparatus. Due to the decomposition of water molecules into 2 elements, oxygen and hydrogen, hydrogen is obtained. As a result, a gas mixture appears, with which cutting work can be carried out.

Manufacturer

Today, water-based plasmatrons are produced by many foreign and domestic manufacturers. But choosing a truly reliable device is quite difficult, since there are a lot of fakes and uncertified products on the market.

The PURM group of companies is the official manufacturer of welding equipment, devices and machines for plasma cutting. Each device is developed taking into account the harsh Russian operating conditions and is suitable for operation in any climatic zones.

Photo 13. Different types of power supplies from the domestic manufacturer PURM

The company specializes in serial production of certified equipment, supply of components, spare parts and consumables. If necessary, we carry out supervision of installation of plasma cutting machines and production lines, commissioning, warranty and post-warranty maintenance.

Underwater dual electrode welding and cutting technology

Underwater electric arc cutting of metal has found wide application both in the manufacture of pipelines for the gas and oil refining industry and in repair production due to its efficiency and ease of implementation. However, it has significant difficulties of both a technological and metallurgical nature. Technological difficulties lie in the need to ensure the tightness of equipment and materials for igniting the arc under water, which requires the use of tubular electrodes and additional equipment for supplying gas, which creates a bubble in which the arc is ignited. Metallurgical difficulties are caused by the hydrogen-oxygen atmosphere of a vapor-gas bubble, which is formed already during the welding process under water and promotes the oxidation of alloying elements and saturation of the metal of the weld pool with hydrogen, and accelerated cooling by the surrounding water leads to its retention in the weld metal and the formation of hardening structures.

Dual exothermic electrodes can also be used for underwater cutting of metal. This technology consists of placing electrodes parallel to each other and connecting them to the terminals of an AC power source. This technology allows you to ignite an arc between the electrodes above water and bury it to a small depth to the welding site. Ignition of an arc under water is possible using an oscillator. In this case, the ends of the electrodes must be insulated, for example with hot glue, with an air channel provided between their ends. After the arc is ignited, the electrodes are brought closer to the parts. As soon as the distance between the electrodes and the workpiece becomes less than the distance between the electrodes themselves, the arc begins to burn between the electrodes and the workpiece, which allows both welding and metal cutting.

Features of a plasma torch on water

A plasma torch is a device that is subject to high thermal loads. Correct operation of the cooling system of a water plasma cutter ensures a longer service life of consumables and prevents heating and melting of the main elements of the device.

The main heat sources in the plasma torch design include the electrode and power cables in the hose package. A plasma arc is connected to the surface of the cathode, resulting in a large amount of energy being applied to the small metal part. Therefore, the electrode is continuously cooled - coolant constantly circulates along its back side.

The power cables in the hose package have a small cross-section relative to the current passing through them, so they generate a large amount of heat. To avoid overheating and melting of the insulation, coolant also circulates through the hose package.

Figure 6. Schematic diagram of plasmatron water cooling

Cooling principle of the plasma cutter:

• The coolant inside the device is initially in contact with the electrode. It has a small hole for liquid flow, which ensures high flow rate along the back wall and efficient heat dissipation.
• Then the coolant is directed into the plasma torch body, and from there through another channel to the nozzle.
• After this, the refrigerant is returned through the hose package to the cooling device.

Rope metal cutting

Rope cutting of metal is a fast and technological solution to global problems.

When cutting with a diamond wire, no sparks are generated, the process is completely controlled by the operator and is so safe that it can be carried out in existing production conditions. We have successfully cut steel, cast iron and slagged metal (scrap).

The scope of application of rope systems is not limited to industrial dismantling of metal structures; this also includes high-precision work on cutting metal elements, where methods such as gas and abrasive cutting are not permissible.

DIAMONDTECH CONSTRUCTION offers not only the service, but also the rental of rope systems with an operator for metal cutting, since we understand that such projects often require a special approach to pricing.

Diamond cutting using wire systems is calculated based on the area of ​​the cut. Here it is clear and easy to understand, since the cut is made by a loop of diamond wire, which encircles the structure being cut, and the area of ​​this cut in square meters is the main design parameter.

If your facility requires wire cutting, contact a DIAMONDTECH CONSTRUCTION specialist and we will select the most effective solution.

Payment options – cashless payment (including VAT or without VAT). Flexible system of discounts up to 20% when paying without VAT.

All work is carried out using tap or imported water in containers.

Depending on the reinforcement of reinforced concrete, the grade of concrete, the temporary conditions of the work, the complexity of the work - cramped conditions, number of floors, the presence or absence of an elevator, the volume of work, the lack of electricity or water at the site, the cost of services indicated in this price list will vary upward or downward .

The cost of services indicated in the price list is not a public offer. To calculate the exact amount taking into account all work conditions, please contact the specialists of DIAMONDTECH CONSTRUCTION.

Very often there is a need to dismantle a large volume of reinforced concrete, but the use of heavy construction equipment is impossible. For example, dismantling bridges, crane foundations, work at industrial facilities, hydroelectric power stations, etc. require the use of wire rope diamond cutting systems.

The cost of such work is determined individually after a DIAMONDTECH CONSTRUCTION specialist visits the site. Often the accompanying work on installing the rope system and lifting mechanisms for dismantling the cut fragments takes up most of the working time compared to the cutting itself. Therefore, it is almost impossible to adequately assess and formulate the final cost of work without taking into account all the nuances of the object.

If your facility requires wire cutting of concrete, contact a DIAMONDTECH CONSTRUCTION specialist and we will select the most effective solution.

Payment options – cashless payment (including VAT or without VAT). Flexible system of discounts up to 20% when paying without VAT.

All work is carried out using tap or imported water in containers.

Depending on the reinforcement of reinforced concrete, the grade of concrete, the temporary conditions of the work, the complexity of the work - cramped conditions, number of floors, the presence or absence of an elevator, the volume of work, the lack of electricity or water at the site, the cost of services indicated in this price list will vary upward or downward .

The cost of services indicated in the price list is not a public offer. To calculate the exact amount taking into account all work conditions, please contact the specialists of DIAMONDTECH CONSTRUCTION.

Wire diamond cutting has a very wide range of applications. Typically, non-standard tasks are assessed individually based on the customer’s technical specifications or a site visit.

The price for rope cutting for non-standard work is formed from a number of factors that influence the cost: the complexity of the task and the completion time, the consumption of materials and the involvement of special personnel, such as divers or climbers.

If your facility requires wire cutting of metal or other non-standard tasks, contact a DIAMONDTECH CONSTRUCTION specialist and we will select the most effective solution.

Payment options – cashless payment (including VAT or without VAT). Flexible system of discounts up to 20% when paying without VAT.

All work is carried out using tap or imported water in containers.

Depending on the reinforcement of reinforced concrete, the grade of concrete, the temporary conditions of the work, the complexity of the work - cramped conditions, number of floors, the presence or absence of an elevator, the volume of work, the lack of electricity or water at the site, the cost of services indicated in this price list will vary upward or downward .

The cost of services indicated in the price list is not a public offer. To calculate the exact amount taking into account all work conditions, please contact the specialists of DIAMONDTECH CONSTRUCTION.

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Types of plasma devices

Water plasma cutters for plasma cutting are available in different types according to design and technical characteristics. Therefore, you need to select a device taking into account the thickness of the material being cut and the maximum operating parameters of the power source from which the plasma torch will operate.

Photo 7. The process of separation cutting with a water plasma cutter

Typically, water-cooled plasma cutters are used in conjunction with power supplies whose operating current exceeds 100 A. These include professional models designed for long-term continuous operation in production conditions.

The design of standard plasma torches for manual and mechanized cutting, where the operating current does not exceed 100 A, includes an air cooling system. At such operating parameters, less heat is generated, so conventional air cooling is sufficient for the device.

Photo 8. Process of manual plasma cutting of sheet metal

Classification of plasma torches by purpose:

• For manual cutting - supplied assembled with a cable-hose package, inside of which there are power cables for connecting to a power source and tubes for coolant circulation.

Photo 9. Appearance of the device for manual plasma cutting.

• For automatic cutting – they are installed on special transverse movement mechanisms in the design of industrial equipment.

Photo 10. Plasma cutter installed on a gantry plasma cutting installation

On automated CNC plasma cutting lines, the plasma torch is installed on a special portal unit, which ensures the movement of the working head in the transverse and longitudinal direction. The design of hand-held plasma torches does not provide for the possibility of stationary mounting - during the work process, the cutter holds the device in his hands.

Safety precautions

The waterjet cutting process is not particularly dangerous. The distance from the tube from which the jet comes out to the surface being treated is only 2.5 mm. This eliminates the impact of the jet on the hand. When the water pressure exceeds the permissible limit, a relief valve opens, which reduces the pressure to operating pressure. However, certain safety precautions should be observed when working on machines.

• Do not expose your body to the jet under any circumstances. Such a jet is capable of cutting metal 150 mm thick, let alone a hand. While working, keep your hands as far as possible from the cutting area. Before turning on the machine, make sure there are no foreign objects in the cutting path.
• Protect your eyes and hearing. Be sure to wear safety glasses and earplugs (or headphones).
• Do not place your hands on your desk.

The leaders in the production of waterjet cutting machines are the American companies Jet Edge, Flow, OMAX, and the Italian WaterJet Corp Inc. and Caretta Technology, Dutch Resato, Czech PTV, Swedish Waterjet Sweden, Finnish ALICO, Swiss Bystronic.

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