A liquid dispensing device includes a dispensing head, an outlet valve and a nozzle. The dispensing head includes an inlet valve, a piston and a piston chamber, an actuator for controlling the piston, and a buffer or bladder. The outlet valve has a defined minimum opening pressure and is in direct fluid communication with either the buffer or bladder, or both the buffer or bladder and the piston chamber. The nozzle, with a defined throughput, is in fluid communication with the outlet valve. A volume of the piston chamber, a volume of the buffer, a pressure response of the buffer, the throughput of the nozzle, and the minimum opening pressure of the outlet valve are together arranged to restrict the outlet pressures of liquid droplets exiting the nozzle within a defined range of from (P??P) to (P+?P), where P is a nominal pressure and ?P a maximum pressure variation.

A packaging device, particularly for packaging trays containing food products or technical materials in a controlled atmosphere and by means of a film of plastic material, comprising an upper chamber and a lower chamber, which can be fastened by mutually superimposing them and are each provided internally with a plurality of heat-sealing and/or cutting and/or die-cutting elements arranged concentrically, the lower chamber being provided centrally with a plurality of supporting elements for a tray.

The invention relates to a packaging machine including a sealing device, said sealing device comprising at least a first and an individually controllable second sealing tool for producing a first and a second seal uniting a lower web with a top web.