A screw heat exchanger combines two tasks in one machine: it conveys bulk materials, slurries, or pastes and heats or cools them at the same time. The component can operate as a cooling screw, a heating screw, or a continuous tempering section, thus often replacing a combination of a conveyor, heat exchanger, and mixer. In this guide, you will learn how a screw heat exchanger works technically, which designs and heat transfer fluids are available, and in which industries the heating or cooling screw shows its strengths.<\/p>\n\n\n\n
A screw heat exchanger, also called a thermal screw or thermal screw conveyor, is a screw conveyor with an integrated heat transfer surface. As the bulk material moves through the trough, a heat transfer medium flows in parallel through hollow components of the screw. Through direct contact with the metal surfaces, heat is either introduced into the product (heating screw) or removed from the product (cooling screw). The process is indirect, meaning the product and the heat transfer medium do not come into contact with each other.<\/p>\n\n\n\n
Key Features of a Screw Heat Exchanger at a Glance:<\/p>\n\n\n\n
Heat exchanger screw, thermal screw conveyor, cooling screw conveyor, and heating screw conveyor all describe the same operating principle. In English, the term screw heat exchanger<\/em> common.<\/p>\n\n\n\n Heat transfer occurs through three possible contact surfaces:<\/p>\n\n\n\n Depending on the requirements, plant manufacturers combine these three surfaces individually or together. With generous design, screw heat exchangers achieve fill levels of up to 90 percent and thus a very good surface-area-to-volume ratio. This is a key advantage over conventional plate heat exchangers or fluidized bed coolers: screw heat exchangers require significantly less installation space.<\/p>\n\n\n\n The medium used depends on the target temperature, the bulk material, and the existing infrastructure. Common options include:<\/p>\n\n\n\n Screw heat exchangers come in various designs, which are adapted to the properties of bulk materials and process requirements:<\/p>\n\n\n\n SEGLER's spiral heat exchangers can be configured in the following variants:<\/p>\n\n\n\n A heating or cooling screw combines several process steps in one machine. This offers concrete advantages for operators:<\/p>\n\n\n\n SEGLER supplies screw heat exchangers for four key industries. While the requirements vary significantly, the basic principle remains the same.<\/p>\n\n\n\n In the chemical industry, screw heat exchangers, specifically cooling screws, are an integral part of many processes. Typical applications include:<\/p>\n\n\n\n Corrosive and abrasive media are contained through material selection, coatings, and cladding.<\/p>\n\n\n\n In the food industry, the heating screw performs tasks such as hygienizing, conditioning, and controlled heating of powders, granules, or pastes. A cooling screw, for example, is used after drying or baking processes to bring the product to storage temperature before packaging. The construction meets the requirements of Hygienic Design:<\/p>\n\n\n\n In the energy and environmental sectors, cooling screws are primarily used for the removal and temperature control of hot residual materials: bed ash and fly ash from incineration plants, pyrolysis products, or residues from thermal recovery processes. Heating screws, in turn, are used for the pre-drying of sewage sludge and similar sludges, as well as for process steps in biomass and alternative fuel processing. The robust design can withstand high temperatures and abrasive media.<\/p>\n\n\n\n In the case of mineral raw materials, fertilizers, salts, or building materials, screw heat exchangers are used for controlled temperature management downstream of reactors, dryers, or mills. Here, too, the screw heat exchanger replaces the in-line arrangement of a conveyor and a heat exchanger, reducing the footprint in the process.<\/p>\n\n\n\n An economic design is based on empirical procedures, supported by thermodynamic calculations and tests with the original bulk material. The following input parameters determine the design and size:<\/p>\n\n\n\n On this basis, screw diameters, pitch, rotational speed, material, and heat exchange surface area are dimensioned. For critical bulk materials, a test in the technical center is recommended to realistically evaluate heat transfer coefficients and adhesion behavior.<\/p>\n\n\n\n Mechanically, both machines are identically constructed. The difference lies solely in their function: a cooling screw removes heat from the bulk material, while a heating screw adds heat. The same machine can be operated in both directions via the heat transfer medium and its flow temperature.<\/p> <\/div> Operating Principle: How a Screw Heat Exchanger Works<\/h2>\n\n\n\n
\n
Heat transfer fluids<\/h3>\n\n\n\n
\n
Designs: Single-wall, double-wall, and special designs<\/h2>\n\n\n\n
\n
Design Options for SEGLER<\/h3>\n\n\n\n
\n
Advantages of Screw Heat Exchangers at a Glance<\/h2>\n\n\n\n
\n
Fields of application: In which industries do helical heat exchangers work<\/h2>\n\n\n\n
Chemistry<\/h3>\n\n\n\n
\n
Groceries<\/h3>\n\n\n\n
\n
Energy and Environment<\/h3>\n\n\n\n
Raw and basic materials<\/h3>\n\n\n\n
Design: What counts when planning a heating or cooling screw<\/h2>\n\n\n\n
\n
Frequently Asked Questions about Shell and Tube Heat Exchangers<\/h2>\n\n\n\n