Mini-silencer for IC engine driven portable chain saws - has diffuser pipe discharging to expansion chamber and two flow reversals in outlet

摘要

The mini-silencer, esp. for IC engine driven chain saws, comprises a two-part casing forming an expansion chamber. Gas enters this through a diffuser pipe (4) pref. curved and with sideways outlet openings (6) set offcentre close to one chamber wall. In the centre, two parallel ducts (8) of differing cross-section carry most of the gas from near the inlet pipe entry point (5) to a receiver (9) near the opposite end of the chamber; some gas enters this directly through a sideways opening (11). Flow is then reversed, going up a duct (13) secured to the casing. The transfer opening (12) is fitted with a spark trap (16). A further flow reversal, by the duct end wall (14') leads the gases to the outlets, along-side the duct.