The main purpose of degassing in an RH unit is to remove the dissolved hydrogen content in liquid steel . presently the minimum hydrogen level aſter treatment has been as low as 0.6ppm. this is achieved with the help of a strong ejector condenser system capable of aaining a vacuum level of less than 1m bar within 3 minutes and a recirculang rate of liquid seel equivalent to 127tons per minute The two steel pipes are the inlet and the outlet snorkels both of them are completely lined with refractory. The inlet snorkel is equipped with a number of gas injecon pipe arranged in the lower secon. The reacon vessel is desined such that the liquid steel is raised through the inlet snorkel and falls back into the steel ladle aſter degassing through the outlet snorkel. The degassing process is started aſter both snorkels are sufficiently immersed into the liquid steel. Before snorkel immersion the injecon of inert gas. Usually argon, is started in the gas pipe of the inlet snorkel. Argon act as a liſter gas to increase the molten steel velocity which is entering into the inlet snorkel. Aſter achieving the required immersion depth of the snorkel, the reacon vessel is evacuated by means of a vacuum pump system which is connected to the reacon vessel through off take duct. The liquid steel density at 1600deg C is assumed at 6.94 tons per cubic meters. This unit shall be high carbon rail steel, low carbon, medium carbon, line pipe steel, ultra low carbon , extra deep drawing quality, boiler, high tensile grades and low alloy steel. The unit shall operate with a nominal het size of 175tons of liquid steel. The plant is desined to aain a minimum vacuum level of 0.67m bar. Design parameters of RH degasser: Type fixed treatment staon Average heat weight (tons) 175 Minimum vacuum level 0.1torr Final hydrogen content <1.5ppm Vacuum system steam ejectors and condensers Circulaon speed (t/min) 127 Preheang tempertureof RH vessel 1400deg C Liſt gas argon Vessel liſting hydrolic system