Labconco Open Combination (Macro) Kjeldahl Systems 2123Series - Manual (Page 14)

Chapter 2: Installation
Product Service 1-800-522-7658 10
WARNING: Acid-resistant duct must be used on the exhaust connection on
your Kjeldahl Apparatus.
(Duct Area in Square Feet) x (Average Airflow Velocity in feet per minute)
= (Air Volume CFM)
(Pi) x (radius²) x (117 FPM) = 25 CFM
The exhaust stack rising from the piping assembly must be vented to the outside
atmosphere via acid-resistant, sealed duct work and a remote blower (not
included). If the remote blower pulls more than 25 CFM at the measurement
point (48” above flexible coupling), close the damper shown in Fig. 2-6 to reduce
airflow to the recommended 25 CFM.
Highly corrosive fumes produced from boiling sulfuric acid will flow through
the ductwork, so acid-resistant duct must be used. Polyvinyl chloride (PVC)
or fiberglass duct is recommended. The exhaust duct work must be supported
independent of the Kjeldahl System to avoid distortion of the piping assembly.
Digestion Rack Drip Shield
The digestion heaters are located in a drip shield and constructed of stainless steel
which is resistant to acid attack. Liquid acid spills that occur can be drained to an
acid-resistant container with the drip tube located on the left side of the digestion
rack.
Digestion Rack Drip Tube
Figure 2-7
Duct Acid Drip Tube