Device for connecting an hydrocyclone

The connection unit to mount a hydrocyclone (1) to a distribution/collection system to deliver and extract a liquid, has a tubular piece (4) with a groove around it at the mounting side. A radial projection is at the groove, with an outer diameter (10) which is smaller than the inner diameter (9) of the connection opening, and to lie within the distribution/collection system when installed. A ring seal (3) extends into the distribution/collection system from the outside, with an outer diameter (8) which is larger than the inner diameter (9) of the connection opening and is clamped when the groove of the tube piece (4) is in the installed position. A clamp applies a durable force between the radial projection and a pressure piece (7) fitted outside the distribution/collection system to give the seal (3) an axial compression. The tubular piece (4) has an outer cone, which transits into the groove at its largest diameter which is at least 4 mm larger than the diameter of the groove. The maximum outer diameter of the radial projection is at least 6 mm smaller than the diameter of the groove and is at most 2 mm smaller than the inner diameter (9) of the connection opening. The radial projection has a chamfer to ease the insertion into the connection opening. The tubular piece (4) has a threading to take a screw pressure nut (13) which is tightened to press against the pressure section (7) and give the axial compression to the seal (3). The pressure section (7) is a component part of the pressure nut (13). A clip can be inserted into a groove at the tubular piece (4) to transfer an axial force on to the seal, directly or indirectly. The tubular piece (4) is a component part of the hydrocyclone to be connected, or a connection (19) for the hydrocyclone (1) is screwed to the tubular piece (4), and the extension of the threading is the threading for the pressure nut (13). The screw connection is by a collar sleeve (16) which is rotated to tighten or loosen the connection through the partial left and right threads. The tubular piece (4) can have a hose nipple. The connection opening can have an edge which is not smooth and the groove is smooth. The seal compensates for the irregularity between them by elastic distortion.