Abstract: The composite seal structure includes a carrier ring and a seal element housed in an annular groove formed between a circumferential outer wall and two side walls of the carrier ring. The seal element has a first region in surface-to-surface contact with the annular groove and a second, seal-ing region protruding from the annular groove. A fastening arrangement couples the seal element and the carrier ring to one another. The fastening arrangement comprises a plurality of fastening pins circumferentially arranged around the axis of the carrier ring. Also disclosed is a method for manufacturing the seal structure.

Abstract: The composite seal structure includes a carrier ring and a seal element housed in an annular groove formed between a circumferential outer wall and two side walls of the carrier ring. The seal element has a first region in surface-to-surface contact with the annular groove and a second, seal-ing region protruding from the annular groove. A fastening arrangement couples the seal element and the carrier ring to one another. The fastening arrangement comprises a plurality of fastening pins circumferentially arranged around the axis of the carrier ring. Also disclosed is a method for manufacturing the seal structure.

Abstract: A sensor arrangement used for measuring fouling and/or erosion in a machine. A first piezoelectric transducer, a first plate and eventually a first support member form a first vibrating mass. After electrically stimulating the first piezoelectric transducer, the first vibrating mass starts vibrating mechanically and consequently the first piezoelectric transducer generates an electric resonance vibration; the electric resonance vibration is at a resonance frequency depending on the mass of the first vibrating mass. If the mass of the first vibrating mass changes due to fouling and/or erosion by a flow of working fluid in the machine, also the electric resonance vibration frequency changes; such vibration frequency change may be measured and the corresponding mass change may be determined by comparison with a vibration frequency of a second vibrating mass not exposed to the flow of working fluid in the machine.

Abstract: In a machine, for example a centrifugal compressor, erosion and/or corrosion of a part of the machine exposed to a working fluid to be processed by the machine is/are monitored; a corrosion probe and/or an erosion probe is/are suitably positioned inside the machine; the corrosion probe and/or the erosion probe is provided with a measurement element that is exposed to the working fluid when the machine operates; the measurement element is made of the same material of the part to be monitored so that the measurement element and the part are eroded and/or corroded in the same or similar way and/or at the same or similar rate. Corrosion and/or erosion data detected by the probe are transmitted from the probe to an electronic unit.