Abstract: A non-return valve which upon reversal of the flow direction is rapidly closed without impingement of the valve member on the seat with a bang comprises a stationary valve guide bush wherein the valve member is adapted for axial displacement and whereby between the valve guide bush and the valve member there is provided a slotted space such that the closing movement of the valve member is damped just before it impinges on the seat.

Abstract: The present invention relates to a tube sheet comprising two parallel interspaced sheet members which are provided with aligned bores through which at least partly with interposition of sleeves, extend tubes or tube sections. The sleeves are provided with internal chambers which through openings in the sleeve wall communicate with the space between the sheet members. The tube plate according to the present invention is highly resistant to thermal shocks in that the internal chambers in the sleeves extend to beyond at least one of the sheet members, in particular the thermally heaviest loaded part.