Abstract: The present invention relates to an impingement freezer (1) comprising an outer housing (2) having side walls (3), ceiling (4) and floor (5), where the outer housing (2) comprises gas condition means (6), preferably for cooling gas and encloses a high-pressure chamber (7) formed by one or more ventilators (8) for circulating the gas, side panels (9) and a perforated plate (10), where the high-pressure chamber (7) is positioned so that the perforated plate (10) is facing a conveyor belt (11) for transporting products allowing the gas to be impinged through the perforated plate (10) onto the conveyor belt (11), which is arranged in a zone (19) between the perforated plate (10) and a plate member (12), and where the side walls (3) and the side panels (9) provides a return access channel (18) for the circulated gas, and the zone (19) is provided with at least one open side (20), which is open towards the return access channel (18).