241 GB/T 13756-1992 三足式离心机型式和基本参数 Three-column centrifuge--Types and basic parameters
242 GB/T 13928-1992 微型往复活塞空气压缩机 Reciprocating piston micro air compressor
243 GB/T 13929-1992 水环真空泵和水环压缩机试验方法 Methods of testing for water-ring vacuum pumps and compressors
244 GB/T 13930-1992 水环真空泵和水环压缩机气量测定方法 Methods for the measurement of volume flow of gas of water-ring vacuum pump and compressor
245 GB/T 13931-1992 电除尘器 性能测试方法 Methods of performance tests for electrostatic precipitators