A machine for packaging products (11) with film (12) made of heat shrinkable material, comprises a body (13) containing a lower portion (14) of a shrinkage chamber which houses, wrapped in film (12), a product (11) to be packaged, and a cover (16), hinged to said body (13) and defining an upper portion (17) of the shrinkage chamber. Disposed in the shrinkage chamber (14, 17) are a heating unit (22) and a ventilating unit (26, 27) to create air circulation (29, 30, 31) inside said chamber. The ventilating unit (26, 27) is situated above the heating unit (22) to generate, when in operation, at least a flow of air (31) through the heating unit (22) in the direction of the bottom of the shrinkage chamber (14, 17).
A packaging machine using a heat-shrinkable film comprises a frame (14, 16) for peripheral sealing of a film (19) segment and a tunnel (21) disposed alongside the frame, in which means (27) for air circulation is arranged, which air is heated by electrical heating elements (28) for shrinkage of the sealed film which is introduced into the tunnel. The machine comprises means (34) for detecting a condition associable with the presence in the machine of a product wrapped in a film to be shrunk. This detecting means (34) upon detection of said condition produces a signal (33) for temporary actuation of the hot-air circulation means (27).
A system for sealing a packaging wrapper around an object directs a flow of heated air to end flaps of the wrapper to move the end flaps into sealing contact with a body section of the wrapper to substantially enclose the object. The system includes an oven, a conveyor, a source of heated air and a means for deflecting the flow of heated air to the conveyor to seal end flaps of the wrapper with a body section of the wrapper. In use, an object surrounded by the wrapper body section is moved through the oven on a conveying surface of the conveyor, and heated air is moved through the oven bypassing the conveying surface to a region below the conveying surface. The heated air flow then encounters the means for deflecting the heated air flow, which directs the air flow upward and through the conveying surface to impact and move the end flaps into sealing contact with the wrapper body section.
