Modern metallurgical enterprises are interested in producing products with minimal unit costs, which include the costs of refractory materials. Reduction of unit costs is possible by increasing the durability of the lining of the metallurgical unit. One of the ways to increase durability is to increase the thickness of the working lining. However, for circulating vacuum degasser, the increase in the thickness of the lining of the submersible snorkels is limited by the size of the steel ladle and the technological parameters of steel processing. To solve the problem of changing the geometric dimension of submersible snorkels, it is necessary to study the processes of removing hydrogen from the melt. The paper considers the issues of calculating the rational dimensions of the inlet snorkel of the vacuum chamber of the circulating vacuum degasser. To determine the rational dimensions, a physical simulation of the metal processing process by vacuum in a circulating vacuuming unit was applied. The relationship between the technological parameters of the circulating vacuum system and the size of the inlet snorkel is determined. Based on the revealed patterns, the design of the inlet pipe was changed, which made it possible to reduce the specific costs of refractory materials without changing the technological parameters of vacuum steel processing.