An
exhaust emission control device is provided which can reliably absorb
thermal expansion difference between a particulate filter and a
selective reduction catalyst without causing deposition of
urea.The
exhaust emission control device has a particulate filter 5 and a
selective reduction catalyst arranged in parallel with each other in such a manner that entry ends of them are directed to the same direction, an S-shaped communication passage 9 being provided for introduction of the
exhaust gas 3 discharged from the
discharge end of the particulate filter into an entry end of the adjacent
selective reduction catalyst through turndown,
urea water being addible upstream of the communication passage 9. A mixing
pipe 10 providing a straight portion of the communication passage 9 is provided at its intermediate portion with a double-
pipe portion 18 constituted by overlapped inner and outer pipes 16 and 17 which are relatively stretchable and retractable, the outer
pipe 17 having a terminal end secured to an outer periphery of the inner pipe 16 and being provided at an appropriate position with an axially expansible and contractible
bellows 19, a sealing ring 20 being fitted over an outer periphery of a terminal end of the inner pipe 16.