Patent ID: 7144233

Claim:
A scroll fluid machine comprising: a housing; a driving shaft having an eccentric axial portion at one end and extending axially of the housing from a center; an orbiting scroll comprising an orbiting end plate having an orbiting wrap and being rotatably mounted to the eccentric axial portion; a fixed scroll fixed to the housing and comprising a fixed end plate having a fixed wrap and a discharge hole extending radially, a gas sucked from an outer circumference of the housing being compressed toward a center of the housing in a sealed chamber formed between the orbiting wrap and the fixed wrap to discharge the compressed gas via the discharge hole; and a silencer fitting in the discharge hole of the fixed end plate and having a smaller-diameter inlet hole and a larger-diameter expansion hole to expand or decompress the compressed gas outwards radially, said silencer comprising an adjusting nut having an introduction tube longitudinally of the nut and fitting in the expansion hole of the silencer to vary effective length of the silencer thereby preventing noise effectively.