Production of expanded food crackers

An apparatus for making puffed crackers from a starch-containing raw material by pressure-baking and expanding the raw material within a heated mould, said apparatus comprising:

• a) a heatable stationary upper mould plate having extending therefrom and stationary therewith one or more downwardly directed upper die elements, said upper mould plate is adapted to be adjustably fixed to an upper frame end of said apparatus;
• b) a heatable lower mould plate having one or more upwardly directed die or punch elements arranged in registry with said one or more downwardly directed upper die elements, said lower mould plate is adapted to be moved upwardly and downwardly relative to said stationary upper mould plate and having a carrier member movable therewith;
• c) an optionally heatable intermediate mould plate disposed between said upper mould plate and said lower mould plate and having one or more die holes arranged in registry with said one or more downwardly directed upper die elements and said one or more upwardly directed die or punch elements, said intermediate mould plate is adapted to be moved upwardly and downwardly relative to said upper mould plate and said lower mould plate such that either one or both of said downwardly directed upper die elements and said upwardly directed die or punch elements are caused to be slidably received in said one or more die holes so as to define mould cavities therein;
• d) means for driving and expanding said heated mould, said driving and expanding means is directly connected to said lower mould plate for moving the same and comprises one or more hydraulic cylinder piston unit mounted beneath said lower mould plate, said one or more hydraulic cylinder piston units having a drive shaft connected to said carrier member of said lower mould plate and said drive shaft and carrier member are disposed vertically in line and with the longitudinal axis of said apparatus;
• and
• e) said hydraulic piston cylinder units having stepped interior chambers of different volume to selectively vary the flow of hydraulic fluid therefrom whereby the velocity of the piston cylinder units is caused to be moved in a downward direction at a rate greater than in an upward direction following baking of raw material within said heated mould.