Submerged evaporator comprising a plate heat exchanger and a cylindric casing where the plate heat exchanger is arranged

The invention provides a a heat plate exchanger (4) used in a submerged evaporator (14) that may operate with markedly increased capacity, where the evaporator (14) does not require more space than other known types and have a smaller filling volume of refrigerant (10) than prior art units. The plate heat exchanger (4) is built up with an outer contour that substantially follows the lower contour of the casing (6) and the liquid level in operation of the primary refrigerant (10) which plate heat exchanger (4) comprises plates (34), which plates (34) are provided with a pattern of guiding grooves (36). With such design, much less space is occupied than with prior art types of submerged evaporators. The reason is that the internal volume is better utilised. Typically, there is a cylindric casing (6) with welded or screwed on ends (22), where internally there is mounted a plate heat exchanger (4) having a part cylindric shape and an external diameter which is between 5 and 15 mm less than the internal diameter of the casing (6). Hereby is achieved a submerged evaporator (14) with reduced filling of refrigerant (10).