Toru Iwao

Radiation power emitted from Ar torch short plasma as a function of in-put power in several kW

Abstract When the waste would be reduced by the arc plasma, the radiation power should be put down, because it is a great deal of loss. On the other hand, we can use it as a clean source for heating materials in a vacuum chamber. In this case, it is expected that the radiation becomes greater. In both cases the radiation power emitted from the arc plasmas has to be precisely controlled. We measured the radiation power emitted from a plasma torch as a function of the electric in-put power. The radiation power was measured to be 200–700 W for an in-put power of 2–4.4 kW and increased in proportion to the 1.8th power of the current or near 1.6th power of the in-put power. Therefore, the radiation power increases steeply with the in-put power. The radiation efficiency for a wall-stabilized arc model was 31% in the condition of 2 cm appearance plasma length, 100 A current and 4400 W in-put power. An equipment using a vacuum chamber for the plasma treatment of the hazardous wastes due to the radiation power emitted from torch plasma is proposed.

Anode attachment of torch plasma arc with high-speed lateral gas air and axial plasma gas argon

Torch plasma arcs have useful high-energy and high-current characteristics. Torch plasma arcs can be flexible even if exposed to high-speed laterally flowing gases. This study measured the length, voltage, input power, heat power and heat efficiency of a torch plasma arc to the anode to elucidate their influence upon the plasma torch arc anode attachment with a high-velocity laterally flowing gas. That velocity was varied from 0 to 60 m s−1. The axial plasma gas argon flow rates used were 4, 8 and 12 slpm. Consequently, the input power increased about 8000–16 000 W with these lateral gas air velocities. The heat efficiency decreased with lateral gas air velocity from about 50% to 25% at a current of I = 150 A. The torch plasma arc length, La, was ca 1 cm. The results of this study are applicable for providing electrical power from the ground to high-speed vehicles or vice versa and for reducing anode erosion by anode spot movement.

Radiation efficiency of Ar torch short plasma as function of length near 100 A

When reduction of waste and dissolution of iron are carried out by using arc plasma, we need to reduce the arc radiation power, because there are some cases of damaging the furnace wall due to the radiation. On the other hand, we can use it as a clean source for heating materials. In this case, its expected that radiation becomes greater. In both cases the radiation power from plasmas has to be precisely controlled. So, we measured the radiation power from torches with a plasma length from 1 to 3 cm. The radiation power decreased in proportion to the 1.8/spl sim/1.9th power of the current. The radiation power in a unit length decreases with the appearance plasma length. The radiation efficiency was 41% for the appearance plasma, 32% for the wall-stabilized arc model, and 20% for the plasma torch at 100 A and length of 3 cm.

Radiation efficiency of Ar torch short plasma near 70/spl sim/140 A

When reduction of waste and dissolution of iron are carried out by using arc plasma, one needs to reduce the arc radiation power, because there are some cases where radiation can damage the furnace wall. On the other hand, one can use it as a clean source for heating materials. The authors measured the radiation power from plasma torches. The radiation power increased in proportion to the 1.8-2.0 th power of the current. The radiation power in a unit length increases with the apparent plasma length. The radiation efficiency is 41% for an apparent plasma length of 3 cm and 31% for the whole plasma length of 3 cm due to a wall-stabilized arc model at 100 A.

Displacement of Torch Plasma Arc on Anode by External Magnetic Field

Summary form only given. The plasma arc has numerous applications in materials processing, metallurgy, welding and so on. Types of arc can be categorized by ambient pressure, arc current, and electrode geometry. The interaction of various arcs with applied dc magnetic fields has been researched extensively with regard to applications such as driven arcs, and magnetically balanced arcs. In these applications, the arc is normally moving in the surrounding atmosphere. The plasma arc is a kind of high current magneto-dynamics, and it is known that the arc mode is greatly changed by Lorentz force due to external magnetic field. However, there are few reports about this relation. To understand the quantification of a basic characteristic, the transformation of the plasma arc mode was obtained when an external magnetic field is applied. As the evaluating method of the plasma arc mode transformation, a momentum model was adopted. The momentum model can be calculated by the balance of plasma jet momentum and electromagnetic force. As a result, the displacement of a torch plasma arc on the anode is theoretically estimated to be proportional to magnetic flux density 2nd power of electrode gap and power of plasma current, which is very near to the measured result to be proportional to magnetic flux density, power of electrode gap and power of plasma current.

Radiation power emitted from Ar torch short plasma as a function of input power

We measured the radiation power emitted from a plasma torch as a function of the electric input power. The radiation power was measured to be 700/spl sim/1500 W for the input power of 4400/spl sim/7000 W and increased in proportion to the 1.83th power of the current or to near 1.55th power of the input power. Therefore, the radiation power increases steeply with the input power. The radiation efficiency for a wall-stabilized arc model was 41% in a condition of 2 cm in the appearance plasma length, 150 A in current and 7000 W in input power.

Radiation power emitted from Ar torch short plasma as function of input power in several kW

When reduction of waste and dissolution of iron are carried out by using an arc plasma, we need to decrease the arc radiation power, because there is the possibility of damaging the furnace wall due to the radiation. On the other hand, we can use it as a clean source for heating materials. In this case, its expected that radiation becomes greater. In both cases the radiation power from plasmas has to be precisely controlled. However there has been little reported on the radiation power from the torch plasma. So, we measured the radiation power from torches by using a power-meter.

Highly concentrated radiation from torch plasma for plasma treatment

The torch plasma generated by the plasma torch has the characteristics of high temperature and highly intense radiation. We focused on the radiation that has been ignored as a loss to treat the materials, especially hazardous wastes. The radiation power was 1540 W when the input power was 7000 W and the appearance plasma length was 2 cm at 1 atm. And then, the temperature of the radiation spot concentrated from torch plasma by a lens was measured. The increasing temperature of the radiation spot was 8.2 K. If all the radiation can be focused on the spot, this would lead to thousands of degrees in the temperature rise.

Radiation power of Ar torch short plasma as function of length near 100 A

Summary form only given. When reduction of waste and dissolution of iron are carried out by using arc plasma, we need to reduce the arc radiation power, because there are some cases of damaging the furnace wall due to the radiation. On the other hand, we can use it as a clean source for heating materials. In this case, its expected that radiation becomes greater. In both cases the radiation power from plasmas has to be precisely controlled. We measured the radiation power from a torch. The radiation power increased in proportion to the 1.8-1.0/sup th/ power of the current. The radiation power in a unit length increases with the appearance plasma length.