Double piston portioning apparatus

A method for successively supplying substantially equal portions of a flowable product from a source thereof to a delivery zone, said method including the steps of:

• applying said flowable product to a central compartment;
• directing flowable product from the compartment into a first cylinder which has a moveable first piston therein defining a first chamber, said first piston being moveable in a direction to permit the progressive increase in the volume of said first chamber while material is being directed to the first cylinder, until a predetermined maximum volume is reached;
• directing flowable product from the compartment into a second cylinder which has a moveable second piston therein defining a second chamber, said second piston being moveable in a direction to permit the progressive increase in the volume of said second chamber while material is being directed to the second cylinder, until a predetermined maximum volume is reached;
• causing the volume of the first chamber to decrease from said maximum volume thereof to a minimum volume, as the volume of the second chamber increases to said maximum volume thereof;
• causing the volume of the second chamber to decrease from said maximum volume thereof to a minimum volume, as the volume of the first chamber increases to said maximum volume thereof;
• said product being alternately directed into a respective chamber as the volume thereof increases, and alternately being delivered from each chamber as the volume thereof is caused to decrease;
• directing product delivered from a corresponding chamber during decrease of the volume thereof through the compartment to said delivery zone;
• and
• controlling the movement of the first and second pistons to increase and decrease the volume of the first and second chambers from pints externally of the chambers to cause the increase in volume of one chamber to be directly proportional to the decrease in the volume of the other chamber, and vice versa.