Abstract: A tunnel freezing system employs multiple high velocity refrigerated air impingement jets to quick freeze food products such as hamburger patties and fish or chicken filets. Ultra high molecular weight polyethylene blocks are provided with a multiplicity of internal jet nozzles. These blocks are located in air ducts located above and below a conveyor belt so that the topsides and bottomsides of food products are impinged with the high velocity jets of refrigerated air so as to break up the boundary layer around the products to effect a much higher rate of heat transfer. A dual conveyor line employs direct drive centrifugal fans to deliver high pressure refrigerated air to the air ducts. The air ducts are spaced apart so that return air can freely return to be re-refrigerated after impinging on the food products.

Abstract: A food processing system, particularly a spiral food freezing system, comprises a food processing section, a conveyor belt for conveying food products through the food processing section, and a conveyor belt tension reducer engaged with the conveyor belt to reduce tension in the conveyor belt at a selected location, such as at the commencement of an infeed section to the food processing section. The tension reducer is provided as an infeed assist drive that is engaged with the conveyor belt at the commencement of the system's infeed section to drive slack into the conveyor belt at the transition from a conveyor belt return section to the inlet section.

Abstract: A self-supporting conveyor belt a portion of the length of which follows a helical conveying path comprising a plurality of stacked tiers. The belt includes a plurality of interconnected pivotal link members by which the belt can either collapse or extend along a side edge thereof to follow a curved path. Secured to the link members are wire-formed spacers which extend between adjacent belt tiers, the wire-formed spacers of one tier abutting and supporting an immediately overlying tier. The spacers provide the belt stack with increased lateral stability to prevent destacking while permitting air flow therethrough comparable to prior art spiral belts without spacers and supported by rails.

Abstract: A helical conveyor system in a freezing unit, wherein cold air from an evaporator (20) is fan-forced upwardly through the turns of the conveyor mesh, a primary cold air flow (26) is directed upwardly through the turns of the conveyor mesh, and a secondary flow (28) of cold air is incident on the top turn of the helix. This has the advantage that the coldest air impinges on the product while the latter is still at its warmest.