over the accumulation belt 2 is decelerated again until it comes to a stop the rate of deceleration is also based on the size of the desired gap 11 the person skilled in the art understands that the accumulation belt needs not come to complete stop after each positioning of a container only if one set of containers 1 on the accumulation conveyor 3 is completed the accumulation conveyor 3 comes to a complete stop and two pusher arms 16 grab the containers and feed them to the sealing unit not depicted fig2 shows the unit 2 for feeding containers to be sealed according to fig1 but with an additional sensor 10 which is located upstream of sensor 5 this sensor 10 measures the distance 12 between two containers 1 and 1 u2032 on the feeder conveyer 4 if this distance 12 is smaller than the minimum gap needed for the handover of tray 1 before tray 1 u2032 is coming to the handover position as well the control unit slows down motor 13 of the feeder conveyor 4 to give the accumulation conveyor 3 enough time to increase the distance between tray 1 and 1 u2032 before tray 1 u2032 is in the handover position to the accumulation conveyor this increases the distance between containers 1.