Possible alternatives of locating a gas separating unit in layouts of plants for preparing gas for transporting and for field booster compressor stations (BCS) are examined. Designs of a gas cleaning unit of the first separation stage with a built-in lock interceptor based on vertical apparatuses are presented. The dynamics of development of separating equipment for protecting BCS is discussed. The problem of ambiguities in current normative-technical documents relating to technical specifications of gas preparing equipment before the BCS is identified. Any field gas preparing plant is provided with a separating unit that ensures the desired degree of gas cleaning from liquid and solid (mechanical) impurities and protects the next equipment. Usually, the products recovered from the reservoir include: • liquid (water, methanol, condensate, etc.) and mechanical impurities (in varying degrees in various objects); • salts dissolved in stratal water; and • liquid locks whose volume depends on the diameter and length of the gathering line and the ground relief. Ingress of liquid locks into field objects is common for both gas and gas condensate deposits. Note that the gas parameters (pressure, throughput, temperature, liquid content, etc.) before the input separation units vary considerably with time. In general, at booster compressor stations (BCS), an additional separating unit is not provided past complex gas preparation plants (CGPP): the technology and equipment of the plants ensure cleaning of the gas. An exception may be drying with a solid sorbent, in which case a filter may have to be installed after the adsorber. When a BCS is constructed and installed before a CGPP, the gas pumping unit (GPU) needs to be protected from liquid and mechanical impurities. The protective unit may be of two versions.