What is a Votator ?
The Votator also known as scraper heat exchanger or scraped surface heat exchanger, Votator can be used in almost any continuous treatment process of pumpable fluid or viscous liquid. Most of the Votators adopt the design that the main shaft drives the scraper to rotate and scrape the heat transfer cylinder, while the other Votator does not adopt the design of rotating main shaft. The scraping effect is realized by a cylinder at the end pushing the scraper to move back and forth periodically along the axial direction of the heat transfer cylinder. In addition, there is a terlotherm series vertical scraper type heat exchanger of terlet company in the Netherlands. Its multiple groups of scrapers can scratch the inner and outer surfaces of the material gap layer at the same time, so as to strive for a larger heat transfer area in the valuable production workshop site.
The main components of Votator include rotating spindle, scraper, heat transfer cylinder, etc. The material passes through the annular product layer formed by the main shaft and the inner wall of the heat transfer cylinder; Water, steam, freon, ammonia and other heating or refrigeration media flow through the medium layer outside the heat transfer cylinder; The scraper can float on the rotating spindle. When the motor drives the spindle to rotate, the scraper closely fits the inner wall of the heat transfer cylinder under the action of product resistance and centrifugal force. The scraper continuously scrapes the materials heated on the inner wall surface of the heat transfer cylinder and constantly refreshes the heat transfer surface of the inner wall; Due to the centrifugal force, the product is constantly forced to contact the refreshed inner wall surface of the heat transfer cylinder, which plays the role of stirring and mixing evenly while improving the heat transfer efficiency. In most cases, the cross section of the inner wall of the heat transfer cylinder is circular, and the main shaft and the heat transfer cylinder are set concentrically. However, for processing very sticky products or products that need to enhance the mixing effect, the heat transfer cylinder can be designed as an ellipse, which can reduce the accumulation of materials in the cylinder, reduce overheating through the action of double cams, balance the stress and prevent the main shaft from bending; The main shaft can also be eccentrically arranged in the middle of the heat transfer cylinder to reduce material accumulation and mechanical load.
The main parameters of the Votator include the structure and material of the scraper, the number of scrapers in the circumferential direction of the main shaft, the contact angle between the scraper and the heat transfer cylinder, the annular channel gap of the product layer, the gap of the heat transfer medium layer, the diameter of the heat transfer cylinder, the length of the heat transfer cylinder, the material of the heat transfer cylinder and the pressure resistance range of the material layer, Different processing technologies (such as oil quenching, pasteurization, heating and crystallization) have different requirements for the design of the Votator. The specific details of its design depend on the processing technology characteristics of the product.
In order to increase the production capacity of the whole processing line, several Votators can usually be connected in parallel or in series to meet the production capacity requirements. Due to the wide variety of commercial Votators, they can meet specific processing needs. Therefore, the key is to determine the specific processing needs of products and purchase the most suitable Votators. As the Votator is mainly used in the food processing industry, its design principle also needs to pay attention to the material selection of its parts in contact with food. Only by ensuring the safety and reliability of the hygienic design of the Votator can we better control the food safety. The surface materials in contact with food shall meet the expected use requirements of food. For example, the coating of heat transfer cylinder shall be non-toxic, crack free, anti peeling, corrosion-resistant, wear-resistant and non absorbent, and can withstand the temperature required for processing and heat treatment (such as freezing, sterilization, etc.). Most of the metal contacting the Votator with food is made of stainless steel, generally austenitic stainless steel and martensitic stainless steel. For non-metallic materials on the surface in contact with food, generally choose sanitary synthetic rubber, engineering plastics, silicon carbide, graphite and other materials, and meet the corresponding requirements for food processing and use.
What Does Votator Do ？
Food processing, pharmaceutical, petroleum and chemical industries often face some viscous, highly viscous, granular liquid products or liquid products that require a certain crystallization process. They usually need to complete the heating and cooling, crystallization, pasteurization, cooking, disinfection, gel, concentration, freezing, evaporation and other processes of such liquid products. Because of its special structure, the scraped surface heat exchanger （Votator）, It is an ideal solution to complete these processes. It is a heat exchanger that agitates the material liquid with the help of a rotary scraper and continuously scrapes the heat transfer surface to accelerate the heat transfer efficiency and heat transfer uniformity. The rotating scraper constantly stirs and continuously removes the deposits on the heat transfer surface, which makes it have the characteristics of high heat transfer efficiency, high heating uniformity and no coking film. It is favored by manufacturers in food processing, pharmaceutical, petroleum, chemical and other industries.
In the ice cream production plant, appropriate ice cream mixing raw materials are pumped in o the Votator together with the air. Through the heat transfer of the refrigeration medium (usually ammonia, Freon or carbon dioxide) in the jacket of the Votator and the strong stirring of the scraper, the materials complete the mixing, cooling, crystallization and semi solidification process, so as to obtain fine and smooth ice cream products with good shape and high expansion rate. In the manufacturer of margarine, the Votator is applied to the quenching process of grease. Under the extremely high cooling efficiency, the grease completes the inflation, supercooling and nucleation process, and then the crystal shape is adjusted through the kneading process, so as to produce fine and glossy margarine products with certain ductility, stability and dispersibility. Some food manufacturers use the characteristics of Votator, such as certain shear rate, high heat exchange efficiency and small particle damage, to apply it to the production of cream sandwich products with certain stability, starch gelatinization, emulsifier mixing, caramelization and concentration in candy production and sterilization process in strawberry jam, pudding and other production. Some chemical manufacturers use the Votator for the crystallization performance in highly viscous liquids, and apply it to the processes of dewaxing (petroleum, oil and fat), separation (xylene and chlorinated benzene) and preparation of various fatty acids. In some large-scale biogas plants, it is planned to use Votator to recover waste heat to increase biogas production capacity. Some cosmetics manufacturers use the mixing and crystallization functions of the Votator to improve the production process of lotion based lipstick. Some gelatin manufacturers use the Votator to complete the gelatin concentration and gel process. Other food manufacturers use Votators to complete the continuous ultra-high temperature sterilization process for highly viscous materials (yogurt, sucrose, dairy products, mashed potatoes, etc.). In addition, Votators are also used to study the shear rate, pressure, temperature, residence time, and Heat transfer rate and other key production parameters.
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