指形管锅炉 Clarkson boiler

指形管组合式 thimble tube composite type

指形管燃油式 thimble tube-oil-fired type

指形管式火管锅炉 thimble fire-tube boiler

无座指形管 baseless subminiature vacuum tube

指形冷凝管 finger condenser ; finger-shape condenser ; shape condenser