Exhaust System

      A functioning exhaust system is critically necessary to keep the laboratory room clear of CO and CO2 emission.  The difficulty in creating an exhaust system is due to three main issues: the somewhat large vibrations of the running engine, the extremely high temperatures of the exhaust gasses- upwards of 400F, and the high pressures of the exhaust gasses.  The solution was a one-piece design to reduce the number of joints that needed to be sealed.   

      An exhaust manifold, which consists of a steel flange welded to a steel pipe 7” in length, sits on the motor end.  This manifold is sealed to the engine with an exhaust gasket made of copper.  The copper coils of the waste heat recovery heat exchanger are located on the length of pipe that is connected to the flange.  Additionally, the manifold is welded to a 24” length of 2” diameter flexible steel hose that allows the engine to vibrate freely on it engine mounts.   

      This flexible steel hose, which bends upwards, is welded to a 7-foot length of 2.25” diameter steel pipe.  By welding the hose on both ends, fittings are kept to a minimum.  The 7-foot length of steel pipe is then welded to a swaged 90º mandrel-bend followed by another 4-foot length of exhaust pipe.  This single-piece exhaust system is suspended and supported by anchors in the ceiling.

      The exhaust is piped into an 18” square duct in the wall.  The duct extends upwards 2 feet before exiting to the street, 20 feet above the level of the sidewalk.  On the lab side, this duct is sealed with a sheet-metal plate fitted with a welded pipe that has a 2” diameter.  The sheet is secured to the wall with bolts and sealed with silicone sealant at the edges.  The exhaust pipe from the engine slides over the fitting in the sheet metal plate and is sealed with high temperature chimney adhesive cement.