Open Combination and Hooded Combination Kjeldahl units have digestion and distillation components for nitrogen determination in one space-saving apparatus. 
 
Open Combination Kjeldahl units are supported by a sturdy, tubular steel framework, with the distillation apparatus mounted above the digestion portion. Models are available with the capacity to digest and distill up to 12 samples at a time (Six-Place Open Combination Kjeldahl unit shown). 
 
Hooded Combination Kjeldahl units enclose the distillation and digestion apparatus so that process heat may be contained and vented from the laboratory. The hood surrounding the apparatus includes three collars: one for remotely-located acid exhaust blower connection, one for hood heat exhaust blower connection, and one for auxiliary-air blower inlet connection. Models are available that digest and distill up to 18 samples at one time. 
 
Kjeldahl units require a remote blower to exhaust fumes.