Abstract: The present invention relates to a probe unit comprising a probe (2) having a probe window (3) having a contact surface for facing a high pressure fluid flow, the probe unit comprising a probe housing (1) containing the probe including the probe window, the probe being moveable relative to the probe housing between a first position wherein the window is exposed to the fluid flow and a second position wherein the probe is enclosed by said housing and a space (11) is defined between said housing and said probe, said housing having an outer part into said fluid flow, said probe unit comprising sealing means (4, 5, 7) adapted to seal said defined space from said fluid flow when the probe is in said second position. The probe unit also comprises pressure adjustment means for reducing the pressure within said space and cleaning means (6, 9) for cleaning said probe when within said space.

Abstract: The present invention relates to a probe unit comprising a probe (2) having a probe window (3) having a contact surface for facing a high pressure fluid flow, the probe unit comprising a probe housing (1) containing the probe including the probe window, the probe being moveable relative to the probe housing between a first position wherein the window is exposed to the fluid flow and a second position wherein the probe is enclosed by said housing and a space (11) is defined between said housing and said probe, said housing having an outer part into said fluid flow, said probe unit comprising sealing means (4, 5, 7) adapted to seal said defined space from said fluid flow when the probe is in said second position. The probe unit also comprises pressure adjustment means for reducing the pressure within said space and cleaning means (6, 9) for cleaning said probe when within said space.

Abstract: The present invention relates to a system for removing deposits from measuring instruments measuring chosen characteristics of a fluid medium contained in a pipe or container, the measuring instrument comprising a window (10) and a first surface (12) having contact with said medium, said first surface (12) being positioned on one end defining a probe head (2) of an elongated member (13) adapted to be extending through the wall (6) of said pipe or container, the outer end of said member (13) being positioned outside said wall (6), the cleaning system comprising an acoustic transducer (5) positioned on the other end of said elongated member (13), wherein said acoustic transducer (5) is acoustically coupled to the elongated member (13) so as to couple acoustic energy thereto, the acoustic energy propagating along said member (13) to the end (2,12) of the probe (1) being in contact with the fluid inside the pipe or container, the resulting vibrations of which removing any contaminations from said window (10) by i