Abstract: In a compressible unit a plurality of separating discs are provided and adapted to being capable, in a compressed state, of being mounted in and removed from a centrifugal separator rotor, which rotor during operation is rotatable about an axis of rotation. The unit includes a support, a pressure surface, between which the separating discs are disposed abutting against one another. Guide surfaces abut against the separating discs and control radial and polar position. At least one compression mechanism is adapted during compression of the unit to press the support and pressure surface towards one another so that the discs are compressed. During compression, the guide surfaces allow relative movement between the support and pressure surface and the separating discs, and are of at least sufficient extent in the compression direction for the position-controlling abutment between the guide surfaces and the separating discs to be maintained throughout the relative movement during the compression.

Abstract: The invention relates to a heat exchanger plate, and a plate heat exchanger including a plurality of heat exchanger plates. Each heat exchanger plate include a heat transfer area, an edge area, that extends around and outside the heat transfer area, and a number of portholes that extend through the heat exchanger plate and are located inside and in the proximity of the edge area. The porthole is defined by a porthole edge and has a center. The porthole edge has a first edge portion, that faces the edge area, and a second edge portion that faces the heat transfer area. The first edge portion has a corrugation seen from the center of the porthole. The second edge portion has a substantially plane shape seen from the center of the porthole.