Introduction to food machinery
Food industry is the first major industry in the world manufacturing industry. In this extended industrial chain, the modernization level of food processing, food safety and food packaging is directly related to the quality of people's lives and is an important symbol reflecting the degree of national development. From raw materials, processing technology, finished products, packaging to final consumption, the entire flow process is complex, interlocking, each link is inseparable from the international first-class quality assurance and information flow trading platform.
1, The concept of food machinery and classification
Food machinery is to agricultural and sideline products as raw materials for processing edible products used in the mechanical installation and equipment. Food processing industry includes a wide range of ground, such as sugar, beverages, dairy products, pastries, candy, eggs, vegetables, fruit, aquatic products, oils and fats, spices, bento food, soy products, meat, alcohol, canned food, etc., each industry has the corresponding processing equipment. According to the performance of food machinery can be divided into general-purpose food machinery and special food machinery two categories. General food machinery, including raw material disposal machinery (such as cleaning, de-mixing, separation and selection of machinery and equipment), solid and powder disposal machinery (such as crushing, cutting, crushing machinery and equipment), liquid disposal machinery (such as multi-phase separation machinery, mixing machinery, homogenizer emulsification equipment, liquid quantitative proportioning machinery, etc.), drying equipment (such as a variety of atmospheric pressure and vacuum drying machinery), baking equipment (including a variety of fixed box type, Rotary, chain-belt baking equipment) and a variety of tanks used in the processing process.
2, Food machinery commonly used materials
Food production has its own unique way, which is characterized by: contact with water, machinery subjected to high temperatures; often operate at high or low temperatures, machinery in a temperature difference in the environment; direct contact with food and corrosive media, the machinery material wear and tear larger. Therefore, in the selection of food machinery and equipment materials, especially food machinery and food contact materials, in addition to consider the general mechanical design to meet the mechanical properties such as strength, rigidity, vibration resistance, etc., but also need to pay attention to the following principles:
Should not contain elements harmful to human health or food can produce chemical reactions.
Should have a high resistance to rust and corrosion.
Should be easy to clean and can be maintained for a long time without discoloration.
Should be able to maintain good mechanical properties in high and low temperatures.
According to the above principles, the use of materials in the food machinery industry are:
Stainless steel
Stainless steel is an alloy steel that can resist corrosion in the air or chemically corrosive media. The basic composition of stainless steel is an iron-chromium alloy and an iron-chromium-nickel alloy, in addition to other elements can be added, such as zirconium, titanium, molybdenum, manganese,, platinum, tungsten, copper, nitrogen, etc.. Due to the different composition, corrosion resistance properties are different. Iron and chromium are the basic components of various stainless steel, practice has proved that when the steel contains chromium in more than 12%, it can resist the corrosion of various media, the general chromium content of stainless steel does not exceed 28%. Stainless steel has the advantages of corrosion resistance, stainless steel, no discoloration, no deterioration and attached food easy to remove and high temperature, low temperature mechanical properties, and so on, and therefore in food machinery is widely used. Stainless steel is mainly used in food processing machinery pumps, valves, pipes, tanks, pots, heat exchangers, concentration devices, vacuum containers, etc. In addition, in addition to food processing machinery, food cleaning machinery and food transportation, preservation, storage tanks and because of its rust will affect the food hygiene apparatus, also use stainless steel.
Steel
Ordinary carbon steel and cast iron are not good corrosion resistance, easy to rust, and should not be in direct contact with corrosive food media, generally used in equipment to bear the load of the structure. Iron and steel are ideal materials for wear components that are subjected to dry materials, because iron-carbon alloys can have various wear-resistant metallographic structures by controlling their composition and heat treatment. Iron itself is harmless to human body, but when it meets tannin and other substances, it will discolor food. Iron rust can cause mechanical damage to human body when it is flaked in food. Iron and steel materials have their unique advantages in wear resistance, fatigue resistance, impact resistance, etc. Therefore, they are still widely used in food machinery in China, especially flour making machinery, pasta making machinery, puffing machinery, etc. In the steel used, the most amount of carbon steel, mainly 45 and A3 steel. These steels are mainly used in the structural parts of food machinery, and the most used cast iron material is gray cast iron, which is used in the machine seat, press roll and other places that require vibration and wear resistance. Ductile iron and white cast iron are used where the overall mechanical properties are high and wear resistance is required, respectively.
Non-ferrous metals
The non-ferrous metal materials in food machinery are mainly aluminum alloy, pure copper and copper alloy, etc. Aluminum alloy has the advantages of corrosion resistance and thermal conductivity, low temperature performance, good processing performance and light weight. The types of foodstuffs to which aluminum alloy is applicable are mainly carbohydrates, fats, dairy products and so on. However, organic acids and other corrosive substances can cause corrosion of aluminum and aluminum alloy under certain conditions. Corrosion of aluminum and aluminum alloy in food machinery, on the one hand, affects the service life of the machinery, on the other hand, the corrosive substances into the food and endanger people's health. Pure copper, also known as purple copper, is characterized by a particularly high thermal conductivity, so it is often used as a heat-conducting material, which can be used to manufacture a variety of heat exchangers. Although copper has a certain degree of corrosion resistance, but copper on some food ingredients, such as vitamin C has a destructive effect, in addition to some products (such as dairy products) also due to the use of copper containers and odor. Therefore, it is generally not used in direct contact with food, but is used in equipment such as heat exchangers or air heaters in refrigeration systems. In general, food machinery and equipment, once with the above non-ferrous metals for the manufacture of direct contact with food parts or structural materials, is increasingly corrosion-resistant and good hygiene properties of stainless steel or non-metallic materials to replace.
Non-metallic
In the structure of food machinery, in addition to the use of good metal materials, but also the extensive use of non-metallic materials. The use of non-metallic materials in food machinery and equipment is mainly plastic. Commonly used plastics are polyethylenes, polypropylene, polystyrene, polytetrafluoroethylene plastic and phenolic plastic containing powder and fiber filler, laminated plastic, epoxy resin, polyamide, various specifications of foam, polycarbonate plastic, etc., in addition to a variety of natural and synthetic rubber. In the food machinery selection of plastic and polymer materials, should be based on the food medium in the health and quarantine requirements and the relevant provisions of the national health and quarantine authorities to allow the use of materials to choose. In general, where direct contact with food polymeric materials should ensure that absolutely non-toxic and harmless to humans, should not bring bad odor to food and affect the taste of food, should not dissolve or swell in the food medium, not to mention the chemical reaction with food. Therefore, food machinery should not be used in low molecular polymers containing water or containing hard monomers, because such polymers are often toxic. Some plastics work in aging or high temperature, such as high-temperature sterilization, can decompose soluble monomers and diffuse into the food, so that food deterioration.
3, The selection of food machinery principles and requirements
The production capacity of the equipment should meet the requirements of the scale of production. In the selection or design of equipment, its production capacity to adapt to the production capacity of other equipment in the entire production process, so that the equipment has the highest efficiency in use, not running time is reduced to a minimum.
1, Does not allow the destruction of raw materials inherent nutrient content, should also increase the nutrient content.
2, Does not allow the destruction of the original flavor of raw materials.
3, Conforms to food hygiene.
4, The quality of the product produced by the equipment should meet the standard.
5, Performance possible, with reasonable technical and economic indicators. The equipment should also be able to minimize the consumption of raw materials and energy, or have a recycling device to ensure that the production has zui low cost. Low pollution to the environment.
6, In order to ensure the hygienic conditions of food production, these machinery and equipment should be easy to disassemble and wash.
7, Generally speaking, the appearance of the single machine size is small, light weight, the transmission part is mostly installed in the rack, easy to move.
8, As these machinery and equipment and water, acid, alkali and other contact opportunities are more, the requirements of the material should be able to anti-corrosion and rust prevention, and direct contact with the product parts, should be used stainless steel materials. Electric motors should be selected moisture-proof type, and the quality of the self-control components is good and has good moisture-proof performance.
9, Due to the variety of food factory production and can type more, the requirements of its machinery and equipment is easy to adjust, easy to change the mold, easy maintenance, and as far as possible to do a machine multi-purpose.
10, Require these machinery and equipment safe and reliable, easy to manage, simple to operate, easy to manufacture and less investment.
Post time: Apr-01-2023