Blow moulding machine with variable intermediate pressure level

An apparatus for shaping plastics material pre-forms into plastics material containers, said apparatus comprising at least one blow mould, inside which the plastics material pre-form is capable of being expanded by being acted upon with a gaseous medium, a stressing device which acts upon the plastics material pre-forms with the gaseous medium, a first pressure reservoir which provides the gaseous medium for the preliminary blow moulding of the plastics material pre-form at a first pressure, a second pressure reservoir which provides the gaseous medium for the intermediate blow moulding of the plastics material pre-form at a second pressure, wherein the second pressure is higher than the first pressure, and a third pressure reservoir which provides the gaseous medium for the final blow moulding of the plastics material pre-form at a third pressure, wherein the third pressure is higher than the second pressure,

• wherein
• the apparatus has a measuring instrument which determines at least one value which is characteristic of a consumption of the gaseous medium, and a control device which changes at least the second pressure in a manner dependent upon the consumption of the gaseous medium.