The “Holo-Scru” Processor is an indirect heat exchanger comprising of a series of rotating helical ducts or hollow flights. Heat is transferred via a heat exchange agent through the inner surfaces of the hollow flights and shaft. And since the principle of the conveyor is employed – the particles of the material within the mass are subjected to continuous movement by the helices and are constantly changing location. This causes them, as they move through, to come into frequent and repeated contact with the surface containing the heat exchange agent. The slow, rotation, conveying, interfolding and dispersing action increase the heat exchange with the product. The motion is however so mild and gentle that there is no dusting nor particle degradation.
The “Holo-Scru” is widely used for cooling, heating, drying and other operations where heat transfer is involved. Heat transfer agents such as refrigerants, water, steam or hot oil provide for a wide range of processing temperatures. Since assembly may be arranged in tiers, the heat exchange agent for heat sensitive products can be introduced into each tier individually at the desired temperature.
In this way shock treatment can be controlled and undesired chemical reactions avoided. In a continuous operation, by using the proper temperature in each tier, the product can be progressively heated or cooled to meet specific processing requirements. Therefore the “Holo-Scru” transfers energy to the product by conduction.
The “Holo-Scru” Processor has a large heat transfer surface per lineal foot. This area divided into the cubical volume per lineal foot results in an effective layer thickness of approximately one inch. The effective layer of material one inch deep is continuously dispersed over the heat transfer surface by the rotating helical ducts (flights). This means that high rates of heat transfer may be obtained with materials and under conditions otherwise impossible to achieve economically.
The compact design of the “Holo-Scru” Processor not only requires minimum space, but because a number of tiers can be stacked vertically, ground or floor space can be saved. Probably no other heat exchanger requires as little space.
The “Holo-Scru” heat transfer areas are covered with the material being processed, and therefore the thermal efficiency is the much higher than other types of heat exchangers.
Although the “Holo-Scru” Processor can be furnished with a single screw, the standard configuration for most application consists of two or four hollow helical screws. The assembly of the trough and screws – with suitable bearings, synchronizing gear, heat transfer agent connections and material inlet and outlet ports – constitutes a tier. The overall length of a tier ranges from 8 to 27 feet.
According to the particular application, a “Holo-Scru” Processor may consist of one or more tiers. The tiers may be placed one above the other or when necessary, may be strung out horizontally as conveyor system.
The screws are built to suit the application and the diameters can range from 6” – 48” and built of material such as steel, stainless steel, monel and other alloys.
The heart of the “Holo-Scru” Processing System is explained below. The heat exchange agent first moves through a rotary joint and into the hollow shaft of the rotor, down the entire length of the assembly. It then turns into the helical outer portion of the unit, returning through the series of hollow flights to the starting point. Thus, the continuous spiral conveyor action combines the heating or cooling effect of the agent within the conveyor itself. Two or four such units, intermeshing, are normally used. The walls of the troughs are employed as additional heat transfer surfaces.