Patent ID: 7337836

Claim:
A heat exchanger comprising: plates having a pattern of grooves, and inlet and outlet connections, placed so as to form a pack and brazed together so as to form separate channels for two media between alternating pairs of plates; a separation zone having a blocked-off space formed by a barrier of valleys and peaks in contact with each other in alternate pairs of plates at a distance from the connections, a brazing at the edges of the plates and a brazing at the connections, which blocked-off space cannot be reached by any one of the media except during leakage, in such a way that the medium which is not to reach and flow through the respective connection is blocked at the barrier between one pair of plates, whereas the other medium can flow through the separation zone in adjacent channels in surrounding pairs of plates and through the respective connection; and a leakage vent extending from the blocked-off space to the exterior.