Labconco Open Combination (Macro) Kjeldahl Systems 21237 Series - Manual (Page 12)

Chapter 2: Installation
Product Service 1-800-522-7658 9
Water Aspirator Exhaust System
For models with a Water Aspirator
For correct operation, the water aspirator’s 3/4" NPT connection must be
connected to a 3/4" supply line with a minimum of 60 psi line pressure.
The water aspirator system is sized for use with a nominal 3" dia. line. The
aspirator discharge pipe terminates with a 3" dia. PVC coupling to drain and a 1-
1/2" dia., 45
° vent coupling for connection to an air roof vent. The discharge
drain for the aspirator must be acid proof, the discharge water will be acidic. The
drain should be capable of carrying up to 6 gpm (23 lpm) of discharge without
backing up over the 45
° air vent connection on the aspirator. See plumbing
diagram.
The 1-1/2" dia. vent line must be vented to the roof, which prevents an airlock
from occurring within the fume removal manifold and prevent back pressure from
building up within the aspiration system. This vent must be acid resistant
material; acid fumes will be exhausted to the outside through this vent line.
As previously mentioned the drain line must be free of back pressure to prevent
closing of the atmosphere vent and stopping the removal of the acid fumes
through the manifold. The drain on the water ejector system should be a sealed
installation to avoid fumes in the laboratory.
Inside the water aspirator, the position of the water nozzle relative to the fume
manifold is factory set and should not require field adjustments for normal
conditions. Care should be taken to maintain this “set” position when connecting
the water line to the aspirator and should be checked periodically to be maintained
in optimum working condition.
Figure 2-4