Vacuum Pump Degassing Equipment in Steel Vacuum
Vacuum degassing system of molten steel requires the characteristics of large air extraction, high vacuum degree and short time from atmospheric pressure to 180-100 mm mercury column. In order to meet the requirement of vacuum degassing of molten steel, steam jet pump or mechanical pump are mainly used at present.
Mechanical pump is through its studio volume periodically increase and decrease, mechanical inhalation and discharge of gas. Mechanical pumps are suitable for low vacuum (760-1 mm Hg residence) and medium vacuum (1-10-3 mm Hg column). Because mechanical pumps have small exhaust capacity under medium vacuum, strong susceptibility to dust discharge, oil sealing is easily polluted by condensation vapor, and moving parts are easily damaged, so mechanical pumps are only used in small capacity vacuum degassing equipment for molten steel.
Steam jet pump is widely used in vacuum degassing equipment of molten steel at present. Compared with mechanical pump, it has the following advantages:
(1) Under the vacuum required by the vacuum treatment of molten steel, it has a large capacity of pumping air. At present, a large-scale steam jet pump of 800 kg/h has been designed and manufactured in China.
(2) Suitable for extracting dusty gas without setting up a huge dust removal system.
(3) It is simple in structure and occupies a small area. It can not even occupy the production area. It is installed between the pillars in the workshop.
(4) Because there are no moving parts, the operation is safe and reliable, and the maintenance is simple.
(5) The investment in cemetery construction is relatively low, and the steam and water supply facilities needed can be supplied by the power network of metallurgical plants or waste heat boilers.
(6) Generally speaking, because steam jet pump consumes a lot of steam and cooling water, its operation cost is higher, but considering the depreciation of fixed investment, the operation cost is not necessarily higher than that of mechanical pump.
Steam jet pump