Title: Supply milk fresh-keeping frozen water, low temperature frozen water system engineering, low temperature chiller, ultra low temperature frozen water.
(Lingfu Electromechanical-Refrigeration System Overall Solution Leader)
The milk factory mainly uses low-temperature frozen water system, which is used for the rapid cooling of the post-pasteurization section and the refrigerated storage of fresh milk.
 
Milk is a haven for microbial activity. According to the test, the newly squeezed milk is not treated at room temperature. After 12 hours, the microbial content per milliliter of milk can reach 114000, and by 24 hours, it has soared to 1.3 million per milliliter. That's why milk spoilt so easily. Therefore, the milk disinfection and preservation technology is very important.
 
Disinfection of 1. milk
In the production process, the milk that has just been squeezed is generally put into the milk tank and cooled quickly to inhibit the reproduction of microorganisms and extend the duration of the antibacterial properties of the milk. The cooled milk needs to be sent to the factory for processing in time. That is, after filtration, purification, cooling, homogenization, sterilization and packaging processes, it has become the daily drinking of sterilized milk. Sterilization is an important process for the production of sterilized milk. Pasteurization is generally adopted (invented by German microbiologist Louis Pasteur in the 1850 s, hence the name). This method is divided into two kinds of low temperature and high temperature disinfection method. The low-temperature disinfection method is to put the milk in a special pasteurizer and heat the milk to 62 ℃ ~ 65 ℃ for 30 minutes; the high-temperature disinfection method is to heat it to 73.8 ℃ ~ 76.6 ℃ for 1~10 minutes, or 82.2 ℃ for no more than 5 minutes. It is then rapidly cooled to 10°C. The purpose of cooling is to prevent the reproduction of residual spores and to maintain the quality of the milk. In addition, the use of soil can also achieve the purpose of disinfection. That is, after boiling with a strong fire, a cream film is rapidly formed on the surface of the milk (subject to the fact that the milk does not overflow), just like a cloth covering the waves. Calculated from the formation of lipid film, and then cook for 15 minutes, you can achieve the effect of pasteurization.
Milk disinfection must be strictly controlled temperature and time. Otherwise, it will not achieve the purpose of disinfection, but also destroy the nutritional content of milk. This is because: first, long-term high-temperature boiling will change the protein in milk from sol state to gel state, thus causing a large amount of protein coagulation and precipitation; Second, calcium in fresh milk is electrostatically combined with casein to form casein calcium that can be digested and absorbed by human body. Compared with sterilized milk, casein in long-term boiled milk is reduced by about 20%, and calcium is changeable as calcium salt that is difficult to be digested and absorbed by human body; third, long-term boiling will also make lactose coking decomposition, low nutritional value; four is the destruction of vitamin A and other vitamins. Therefore, the sterilized milk is in principle directly to drink, do not have to boil. If you need to heat up, just put the bagged cow in hot water at 50 ℃ ~ 60 ℃ for a while.
Preservation of 2. Sterilized Milk
Sterilized milk is not easy to store at room temperature. Milk * afraid of the sun. Under sunlight, vitamin A, carotene, vitamin B1 and vitamin B12 contained in milk will be destroyed, so it is better to keep away from light and refrigerate. According to the test, the milk is cooled to 13 ℃ and can be stored for 12 hours. Therefore, the temporarily undrinkable bags of sterilized milk can be placed in the refrigerator, but not in the freezer. Because once the milk is frozen and then heated to dissolve, the separation of fat and protein will occur, solidification and precipitation will occur. At this time, the oil will float up, the milk taste will change, and the nutritional value will also decrease. If the milk bought back is self-employed, it should not be kept after boiling and disinfection. If you want to save, you can use a small container, sealed storage, but the time should not be too long.
At present, bagged and bottled milk sold in the market are made by dairy processing enterprises after purchasing fresh milk from dairy farms and professional cattle farmers, and then sterilized and processed. There are two methods for manufacturers to disinfect milk. One is the high-temperature instantaneous heating method, with a temperature of 135 ℃. The second is pasteurization. Pasteurization involves treating milk at 62-63°C for 30 minutes, or heating to 72-73°C for 20 seconds. If the package is well sealed, the bottled milk can be stored at room temperature for several months to one year after leaving the factory. The shelf life of bagged milk is 2-3 days in summer and 5-7 days in winter.
A senior engineer surnamed Zhang from a dairy manufacturer said that liquid milk can be divided into three types according to the production process: sterilized milk, sour milk, and pasteurized milk. In terms of disinfection methods alone, there are "pasteurized milk" and "ultra-high temperature sterilized milk. As far as the packaging form is concerned, it can be roughly divided into four kinds: plastic bags, Tetra Pak, cartons and plastic bottles. Among them, Tetra Pak bottles are divided into pillow type (bag) and brick type (box), both of which are made of 5-7 layers of paper and aluminum foil composite packaging produced by Tetra Pak Company in Sweden. According to experts, the shelf life of milk, drinking methods and packaging have a great relationship, different packaging and disinfection methods determine the shelf life of milk.
Pasteurized milk: also called pasteurized milk. Sterilization at about 80°C for a few seconds is "short-acting milk", which needs to be stored at low temperature, and the shelf life is generally 1-7 days; when the storage temperature exceeds 4°C, the bacteria in the milk can still reproduce, so it cannot be stored for a long time at room temperature. Pasteurized milk, including full-fat, partially skimmed three products, suitable for fast disinfection, high frequency of purchase of families.
Bagged milk is cheap, so it is suitable for delivery to thousands of households and has become a breakfast food for many families. The appearance of the house-shaped fresh milk is packed with paper materials that are dark and conform to the concept of environmental protection, and adopts the international common "cold chain control method", that is, the whole process from fresh milk extrusion to production, storage, transportation and sales is carried out under low temperature conditions, and the shelf life can reach 7 days. One of its characteristics is "fresh": from milk extrusion to product filling within 8 hours; second, the production process is advanced and scientific, the nutritional ingredients are well preserved, and the nutritional indicators are higher than ordinary bagged milk. The house-shaped milk with rich flavor and mellow taste is a fine product in fresh milk, and its price has begun to approach ordinary people after a substantial adjustment. However, because it is still at a disadvantage in price, house milk will not be able to replace cheap bagged sterilized milk for a long time.
Ultra-high temperature (pillow bag/brick box) sterilized milk: also called high temperature milk. Using instant ultra-high temperature sterilization method, in a production line, the sterilization of packaged materials, packaging box forming and packaging are completed at one time, that is, from packaging forming to product filling process, are carried out in the sealed sterile area. The Tetra Pak carton with 5-7 layers of protective film protects the vitamins in milk from the sun. The ultra-high temperature instant sterilized fresh-keeping milk packaged by Tetra Pak is "long-lasting milk" with a long storage period, which can reduce the frequency of consumers to buy. The product itself does not need to be refrigerated, and the shelf life at room temperature is generally 8 months, but the premise is that once the package is opened in the unopened state, it should be placed in the refrigerator for refrigeration, and try to drink it within 3-4 days. Tetra Pak pillow packaging is economical and more suitable for going out to carry.
Milk needs to be cooled quickly at high temperature after sterilization. Generally, low-temperature frozen water is used for heat exchange. Lingfu Electromechanical specializes in designing and constructing pasteurization cooling water systems with rich experience.

Detailed Description of Unit Products
for you recommend chilled water circulation system, (industrial refrigeration unit); refrigerator, freezer, cooling machine, frozen water machine, ice water machine, cooling water device, circulating water cooling system manufacturers collectively referred to as chiller. The refrigeration system of the chiller is composed of refrigerant, compressor, condenser, expansion valve, evaporator, throttling element and five main parts. Can be customized according to the use of ultra-low temperature type (can be as low as minus -40 ℃ ~ 130 ℃) using multi-machine technology, making the refrigeration system stable performance, energy saving, environmental protection, large flow, low noise.
Refrigerant: R22 does not burn or explode, lubricating oil dissolves each other, and its solubility changes with the type and temperature of lubricating oil, so the refrigeration system using R22 must have oil return measures.
Compressor: The compressor is the power of the refrigeration cycle. It is driven by a motor and rotates continuously. In addition to pumping out the vapor in the evaporator in time to maintain low temperature and low pressure, it also increases the pressure and temperature of the refrigerant vapor through compression to create Conditions for transferring the heat of the refrigerant vapor to the external environment medium. That is, low-temperature and low-pressure refrigerant vapor is compressed to a high-temperature and high-pressure state, so that air or water at room temperature can be used as a cooling medium to condense the refrigerant vapor.
Condenser: The condenser is a heat exchange device. Its function is to use the ambient cooling medium (air or water) to take away the heat of the high-temperature and high-pressure refrigeration vapor from the compressor, so that the high-temperature and high-pressure refrigerant vapor is cooled and condensed into high-pressure and normal-temperature refrigerant liquid. It is worth mentioning that the condenser in the process of the refrigerant vapor into a refrigerant liquid, the pressure is unchanged, still high pressure.
Throttling element: The high-pressure and normal-temperature refrigerant liquid is directly sent to the low-temperature scale evaporator, and the pressure of the refrigerant liquid is reduced according to the saturation pressure and saturation temperature-corresponding principle, thereby reducing the temperature of the refrigerant liquid. The high-pressure and normal-temperature refrigerant liquid passes through the pressure-reducing device-throttling element to obtain low-temperature and low-pressure refrigerant, and then it is sent to the evaporator to absorb heat and evaporate. The chiller uses capillary tubes and expansion valves as throttling elements.
Evaporator: The evaporator is also a heat exchange device. After throttling, the low-temperature and low-pressure refrigerant liquid evaporates (boils) into vapor, absorbs the heat of the cooled medium, and reduces the temperature of the medium to achieve the required temperature effect and the purpose of circulating refrigeration.

1. Stable performance: multiple compressors are used in parallel, and each compressor has an independent cooling system circuit, I .e. evaporator and condenser are completely independent; All compressors are commanded by a unified microcomputer control system, turned on and off one by one, and will never interfere with each other. In addition, all brand models are made of original imported originals, and the failure rate of single machines is extremely low. Considering the above reasons, it can ensure that this series of models have highly stable performance and can be selected under continuous operation for many years] without purchasing other spare machines.
2. Power saving and energy saving: multiple small and medium power compressors are used in parallel, and the interference to the power grid during opening and closing is extremely small. With the change of load, the unit will automatically determine the number of starting up to ensure that the opened compressors are in excellent working condition, thus effectively saving electric energy.
3. Long service life: The evaporator and condenser are designed very reasonably and are placed above the compressor. During the entire operation, most of the lubricating oil always stays in the compressor to ensure good lubrication of the compressor.
Chilled water circulation systems are widely used: industry, agriculture, surface treatment, electroplating, laser, printing, food, beverages, cosmetics, toys, chemicals, hardware, building materials, automobiles, electronics, electrical appliances, electromechanical and other 16 major industries, more than 30 Industries; high-power chillers are widely used in hotels and office buildings for central air conditioning, plastic cooling, food preservation, bath temperature reduction, medical storage and other industries.
Protective devices:
1, lack of phase, reverse phase protection device; 2, compressor overload protection device; 3, high and low pressure protection device; 4, water shortage automatic alarm device; 5, low temperature, anti icing protection device; 6, insufficient water flow protection device; 7, automatic temperature control system
Chilled water circulation system (industrial refrigeration unit) structural characteristics

Water-cooled box type design, the water tank is built into the unit, the bottom is equipped with movable casters, the appearance is beautiful, the installation position and equipment can be changed at will, can be placed in the production workshop, and has multi-stage energy adjustment suitable for supporting small and medium-sized production equipment (this model needs to be equipped with corresponding cooling water tower and cooling pump).