Abstract: In a plate heat exchanger having a frame plate and a pressure plate, at least one of these plates has holes for flow of the heat exchanging media to and from respective passages in the pack of heat exchange plates. Each of these holes has a lining of corrosion-resistant metal comprising a hollow cylinder with thin flanges at its opposite ends engaging opposite sides of the frame plate or pressure plate. One of these flanges has a seamless connection with the hollow cylinder and is sealingly compressed between a heat exchange plate and an undepressed surface of the inner side of the adjacent frame plate or pressure plate. Lining of the hole is effected by plastically deforming a metal disc into a hollow cylinder with a flange at one end, inserting the other end of the cylinder through the hole to engage the flange with said undepressed surface, and then providing said other end of the cylinder with a flange engaging an undepressed surface of the outer side of the frame or pressure plate.

Abstract: In a method and an apparatus for safe-guarding a press (1) by monitoring the press motion, use is made of the fact that the force exerted by the press is an almost invariable function of the position of the upper press platen in relation to the lower press platen. The force exerted by the press is continuously sensed during each pressure stroke by means of transducers (6). The instantaneous value of the force is compared in a monitoring unit (10) with a reference force value, calculated during the first pressure stroke, at each one of the subsequent positions of the upper press platen of the press in relation to the lower press platen thereof. This comparison is repeated for each such position during the pressure stroke. The monitoring unit (10) directly interrupts the press motion if, on comparison, the sensed force value in any position deviates from the reference force value by more than a predetermined amount.