Bioreactor vessel having an optical foam sensor

A bioreactor comprising:

• a vessel having a flexible outer wall for containing fluids, the flexible outer wall having an inner surface facing into the vessel;
• a supply of antifoaming agent communicating with the vessel;
• a metering pump for selectively conveying the antifoaming agent to the vessel;
• at least one window mounted to a frame, the frame being welded or bonded to the inner surface of the flexible outer wall of the vessel and having a flange penetrating through the flexible outer wall of the vessel at a position in said outer wall of the vessel so that the window is above the fluids contained in the vessel, said window comprising an outer side and an inner side and being transparent to light from the visible and ultraviolet spectral range;
• an illumination and detection unit having a housing reversibly coupled to the flange that penetrates through the flexible outer wall of said vessel, the illumination and detection unit further comprising at least one first light source of visible light disposed in the housing to direct light through the window and into the vessel, at least one photodetector in the housing and external of the vessel and disposed to detect reflected light from said first light source that is reflected in the vessel and to generate a reflection signal;
• a control unit connected to the photodetector and to the metering pump and operative to actuate the metering pump for conveying the antifoaming agent into the vessel when the reflection signal generated by the photodetector exceeds a threshold value indicative of a specified level of foaming in the vessel and
• the illumination and detection unit further comprises a coupling surface comprising a sealing plate that is transparent to light from the visible and ultraviolet spectral range, and the sealing plate including an electric heating device that is temperature controllable.