Votator(Scraped Surface Heat Exchenger)
The votator is a heat exchange equipment that is especially suitable for processing viscous, high viscosity, particle-containing liquids or liquid products that require certain crystallization applications. It is usually used for heating in food processing, petrochemical, pharmaceutical and other industries. With cooling, crystallization, pasteurization, retort, sterilization, gelation, concentration, freezing, evaporation and other continuous production processes. During the treatment process of the votator, the feed liquid is in contact with the heat transfer surface, and at the same time, the boundary layer of the feed liquid is continuously replaced by the new feed liquid through the continuous scraping of the heat transfer surface by the scraper. At the same time, it can avoid undesirable phenomena such as coking film on the heat transfer surface. Due to the scraping and stirring of the scraper, the materials can be fully mixed, so the votator has the advantages of high heat transfer efficiency and uniform heat exchange effect. The residence time in the votator heat exchanger is typically only a few seconds, so high temperature gradients can be used to transfer heat instantaneously with few other undesired side effects. Therefore, votators are favored by manufacturers of margarine, shortening,butter,candy and ice cream.
Structural Features of Votator
The main components of the Votator include rotating spindle, scraper, heat transfer cylinder, etc. An annular product layer formed by the material passing through the main shaft and the inner wall of the heat transfer cylinder; Water, steam, freon, ammonia and other heating or cooling 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 fits closely with the inner wall of the heat transfer cylinder under the action of product resistance and centrifugal force. The scraper continuously scrapes the heated materials on the inner wall surface of the heat transfer cylinder and continuously refreshes the inner wall heat transfer surface; Due to the effect of centrifugal force, the product is constantly forced to contact the updated inner wall surface of the heat transfer cylinder, which plays the role of mixing evenly while improving the heat transfer efficiency.
In most cases, the inner wall section of the heat transfer cylinder is circular, and the main shaft is concentric with the heat transfer cylinder. However, for processing products with strong viscosity or products that need to enhance the mixing effect, the heat transfer cylinder can be designed in o an oval shape, which can reduce the accumulation of materials in the cylinder, reduce overheating through the function of double cams, balance the stress and prevent the bending of the main shaft; The main shaft can also be eccentrically arranged in the middle of the heat transfer cylinder to reduce material accumulation and mechanical load.
Parameters of Votator
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 range of the material layer, and 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 characteristics of the product.
In order to improve the production capacity of the entire production line, multiple stators can usually be connected in parallel or in series to meet the production capacity requirements. There are a variety of voting machines on the market to meet specific processing needs. Therefore, it is important to determine the specific handling needs of the product and purchase the most suitable rollers. Since Votator is mainly used in the food processing industry, in its design principle, attention should also be paid to the material selection of parts that come in o contact with food. Food safety can only be better managed by ensuring the safety and reliability of Votator's hygienic design. Surface materials in contact with food must meet the requirements for the intended use of the food. For example, heat transfer cylinder coatings are non-toxic, non-cracking, non-peeling, corrosion-resistant, abrasion-resistant, non-absorbent, and can withstand the temperatures required for handling and thermal treatment (eg, freezing, sterilization). ). Most of the metals that make Votator and food contact are stainless steel, generally austenitic stainless steel and martensitic stainless steel. For non-metallic materials on surfaces that come in o contact with food, hygienic synthetic rubber, engineering plastics, silicon carbide, graphite and other materials are generally selected to meet the corresponding requirements of food processing and use.
What Does Votator Do？
The food processing, pharmaceutical, petroleum, and chemical industries often face viscous, highly viscous, granular liquids or liquid products that require specific crystallization processes. They usually need to complete the heating and cooling, crystallization, cold sterilization, cooking, sterilization, gelling, concentration, freezing, evaporation, and other processes of this liquid product. Its special construction, the scraped surface heat exchanger (Votator), is an ideal solution for these processes. A heat exchanger that uses a rotary scraper to stir the feed liquid, continuously shut off the heat transfer surface, and accelerate heat transfer efficiency and heat transfer uniformity. The rotary scraper is characterized by high heat transfer efficiency, high heating uniformity, and no coking film by continuous stirring to remove deposits on the heat transfer surface. Supported by manufacturers in food processing, pharmaceuticals, petroleum, chemicals and other industries.
At the ice cream factory, the appropriate ice cream mix is pumped in o the votator along with the air. By heat transfer of the refrigerant (usually ammonia, freon, or carbon dioxide) in the jacket of the baking machine and strong agitation of the scraper, the material completes the process of mixing, cooling, crystallization, and semi-solidification to fineness. with votator process, a smooth ice cream product with a good shape and a large overrun produced. Among the margarine makers, Votator is suitable for the oil and fat quenching process. Under very high cooling efficiency, the margarine completes the expansion, supercooling, and nucleation processes, and then to produce a fine glossy margarine product with specific ductility, stability, and dispersibility. Adjust the crystal shape through the (Pin Rotor) kneading process. Some food manufacturers have specified shear rates, high heat exchange efficiencies, and small particles in the production of certain stability, gelatinization of starch, mixing of emulsifiers, caramelization, and confectionery production of condensed cream sandwich products. Uses Votator characteristics such as Sterilization process in the manufacture of strawberry jam, pudding and others. Some chemical manufacturers use Votator for dewaxing (petroleum, grease), separation (xylene, chlorobenzene), and crystallization properties of high viscosity liquids for various buty acid preparation processes. Some large biogas plants plan to use Votator to recover waste heat and increase biogas production. Some cosmetic manufacturers use Votator's blending and crystallization capabilities to improve the process of making lotion-based lipsticks. Some gelatin manufacturers have used Votator to complete the process of gelatin concentration and gelation. Other food manufacturers are using votator in a continuous UHT process for high viscosity materials (yogurt, sucrose, dairy products, mashed potatoes, etc.). In addition, votators are used to study shear rates, pressures, temperatures, residence times, heat transfer coefficients, and other key production parameters.
1 Sullo A, Arellano M, Norton I T. Formulation engineering of water in cocoa – Butter emulsion [J]. Journal of Food Engineering, 2014, 142(11):100-110.
2 Rønholt S, Kirkensgaard J J K, Høyer K F, etc. The effect of capacity, rotational speed and storage on crystallization and rheological properties of puff pastry butter [J]. Journal of the American Oil Chemists Society, 2014, 91(1):29-38.
3 émilie Lefébure, Sébastien Ronkart, Brostaux Y, etc. Investigation of the influence of processing parameters on physicochemical properties of puff pastry margarines using surface response methodology [J]. LWT-Food Science & Technology, 2013, 51(1):225-232.
4 Miskandar M S, Man Y B C, Yusoff M S A, etc. Effect of scraped-surface tube cooler temperatures on the physical properties of palm oil margarine [J]. Journal of the American Oil Chemists' Society, 2002, 79(9):931-936.
5 S. Rønholt, Kirkensgaard J J K, K. F. Høyer, etc. The Effect of Capacity, Rotational Speed and Storage on Crystallization and Rheological Properties of Puff Pastry Butter [J]. Journal of the American Oil Chemists' Society, 2014, 91(1):29-38.
6 Luca D’Addio, Carotenuto C, Natale F D, etc. A new arrangement of blades in scraped surface heat exchangers for food pastes [J]. Journal of Food Engineering, 2012, 108(1):143-149.
7 Wang Y Y, Russell A B, Stanley R A. Mechanical damage to food particles during processing in a scraped surface heat exchanger [J]. Food and Bioproducts Processing, 2002, 80(1):3-11.
8 Rao C S, Hartel R W. Scraped surface heat exchangers [J]. Critical Reviews in Food Science & Nutrition, 2006, 46(3):207-219.
9 Chen J, Ma C, Ji X, etc. Mechanism of waste-heat recovery from slurry by scraped-surface heat exchanger [J]. Applied Energy, 2017, 207(1): 146-155.
10 Beri A, Pichot R, Norton I T. Physical and material properties of an emulsion-based lipstick produced via a continuous process [J]. International Journal of Cosmetic Science, 2014, 36(2):148-158.