Detailed introduction
　　1. Definition: Stirring yoghurt production line equipment is a kind of yoghurt product which mixes jam excipients and yoghurt gel after fermentation, and then puts it into cups or other containers, then cools and ripens. The main strains are Lactobacillus bulgaricus and Streptococcus thermophilus.
　　II. Equipments Process of Stirred Yoghurt Production Line
　　1. Principle of production:
　　Under the action of lactase, lactose is first decomposed into molecular monosaccharides and lactic acid is further produced under the action of lactic acid bacteria; lactic acid transforms colloidal calcium phosphate in casein colloidal particles into soluble calcium phosphate, which decreases the stability of casein colloidal particles, and at PH4.6-4.7, casein agglutinates and precipitates to form yoghurt.
　　2. Process flow
　　(1) After filtering, the fresh milk is put into the heating cylinder. When the milk is preheated to 50-60 degrees, half of the white sugar used for production is added into the milk. The temperature is raised to 70 degrees. The homogenization pressure is controlled at 18-20 MPA0, then the temperature is kept at 90 degrees for 10 minutes. After that, the temperature is lowered to 43-45 degrees and the temperature is kept constant. The strains used for production are added into the milk according to 3% of the fresh milk volume. Fermentation for 3-5 hours, fermented milk PH control in 3.8-4.15 is better, stop fermentation. Cool rapidly below 30 degrees, stirring slowly.
　　(2) Preparation of stabilizer mixture: 1/2 of white sugar for production is mixed with stabilizer, protein sugar, potassium sorbate, and dried. When stirred, it is sprinkled into 80-85 degree hot water (95% of the water required for production) to prevent powder bonding. If a colloid block appears, it can be crushed through colloid mill once, such as soaking the stabilizer mixture for 3-5 hours in advance, the effect is better. It is then cooled to 25-35 degrees.
　　(3) Mixing fermented milk and stabilizer mixture at low temperature (usually 25-35 degrees) and evenly measuring its acidity, PH is above 4.2. For example, 2/3 of the citric acid diluent (5% of the water used to dilute citric acid in production) is mixed and sprinkled into the feed solution to measure its acidity until the PH of the feed is about 4.
　　3. Block diagram of process flow
　　(1) 3. Major equipment and instructions (no less than three)
　　1. Main equipment for yoghurt production: a homogeneous mechanical equipment B plate sterilization technology equipment C fermenter
　　2. Explanation of Yogurt Production Equipment
　　A, Name: Homogenizer is mainly used for tissue dispersion in biotechnology, sample preparation in medicine, enzymatic treatment in food industry, pharmaceutical industry, cosmetics industry, paint industry and petrochemical industry. The device adopts stainless steel system, which can effectively separate the surface of the sample and the microorganisms included. The sample is packed in a disposable sterile homogeneous bag, and does not contact the instrument. It meets the requirements of fast, accurate and good repeatability.
　　Application of Homogenizer in Food Processing:
　　1-Drive Shaft 5-Inhalation Valve 9-Exclusion Valve 2-Body 6-Homogeneous Valve 3-Sealing Gasket 7-Stem 4-Piston 8-Pressure gauge 9-Exclusion Valve
　　The working principle of homogenizer:
　　1. Precision matching of rotor and stator, claw structure of working head (made of rotor and stator forgings), bidirectional suction, high shearing efficiency. Intermittent high shear dispersed emulsifier is a kind of high frequency, strong circumferential tangential velocity, angular velocity and other comprehensive kinetic energy efficiency through high speed and smooth rotation of the rotor. Under the action of the stator, strong and reciprocating hydraulic shearing, friction, centrifugal extrusion, liquid flow collision and other comprehensive effects are formed in the reasonable narrow gap between the stator and the rotor, and the material is reciprocating in the container. Work on the process, and ultimately get the product.
　　2. Homogenizer features: stable operation, low noise, easy cleaning, flexible, continuous use, superfine dispersion and emulsification of materials. It can be widely used in emulsification, homogenization and dispersion of industrial production. · It can make the material refined and mixed under the triple action of extrusion, strong impact and pressure-loss expansion. This equipment is an important equipment in food, dairy and beverage industries. · Homogenization of milk, soybean milk and other dairy beverages under high pressure can significantly refine the fat globules in the milk, make the products easy to digest and absorb after eating, and improve the use value. · When used in the production of ice cream and other products, it can improve the fineness and looseness of the liquid, and obviously improve its internal texture. · Used in the production of emulsion, gel, juice and slurry, it can prevent or reduce the grading of the material, improve the appearance of the material, make it brighter in color, stronger in fragrance and more mellow in taste.
　　3. Application of homogenizer in raw milk: 16.7-20.6 MPa crushes large fat ball into small fat ball under strong mechanical action. Make it evenly and uniformly dispersed in milk. It can effectively prevent the fat ball from floating. In the production of pasteurized milk. Generally, the homogenizer is located in the first heat recovery section of sterilization. In the production of indirectly heated ultra-high temperature sterilized milk, the homogenizer is located before sterilization. In the production of directly heated ultra-high temperature sterilized milk. Homogenizer is located after sterilization. Therefore, sterile homogenizer should be used. Homogenization not only prevents fat globules from floating, but also has some other advantages: after homogenization, the diameter of milk fat globules decreases, which is easy to be digested and absorbed by human body. Homogeneity softens milk protein clots. Promote digestion and absorption. In the production of cheese by enzyme, homogenization can accelerate the coagulation of milk and make the flavor of dairy products more consistent.
　　Homogenizer Operating Rules
　　1. Start-up: Turn on the cooling water and turn on the power switch. The handle of the secondary valve and the handle of the primary valve are loosened, and 2/3 hot water is injected into the hopper (water temperature 75-85 C). Then start the electric vehicle, make the material pipe water flow out normally, and circulate with the hot water in the hopper, so that the homogenizer preheat to the ideal temperature and wait for the material.
　　2. Homogenizer Pressure: Second-stage valve first boost. When there is no abnormal noise in the machine, the hot water is emptied, and then the material is added. Attention should be paid to ensuring continuous feeding and discharging of homogenizer when adding materials to avoid air mixing. When the mixture of material and water is discharged, the material of the material pipe and hopper is recycled and the secondary valve handle is gradually tightened. Then the pressure gauge shows the corresponding pressure value, and then the secondary valve handle is tightened gradually until the pressure gauge shows the required pressure value. Be careful not to exceed the upper limit of its rated pressure. The primary valve is boosting. Gradually tighten the pressure gauge of the first valve handle until the pressures are shown.
　　3. Discharge: After completing the above operation procedure, the material pipe is connected to the material container.
　　4. Pressure relief: At the end of the load operation of the homogenizer, all the working valve shanks must be loosened. First, the first-class valve shank is loosened, then the second-class valve shank is loosened, so that the pressure gauge is shown to be zero.
　　5. Cleaning: After the homogenizer works, clean the material of pump body and working valve body with clean water (using hot water, water temperature 65-75 C), and drain the water.
　　6. Shutdown: Cut off the power supply and turn off the cooling water.
　　Homogenizer Maintenance
　　1. The starting and pressing steps of the machine shall be specified in accordance with the operating procedures.
　　2. After the machine is used, the material passage should be cleaned in time with clean water, especially at the contact of valve seat and valve core, to clean the residual material and prevent sticking, so as to ensure the normal operation of the next start-up.
　　3. If the machine is out of service for a long time, a complete CIP cleaning should be done before use. Wednesday is a single alkali cleaning, and Friday is a complete CIP cleaning.
　　4. Check the location of lubricating oil in gearbox and crankcase frequently. The lubricating oil should be kept clean. When deterioration or failure is found, new oil and new sealing ring should be replaced in time.
　　5. Homogenizer is overhauled quarterly.
　　6. When cleaning the homogenizer, brushes, wire balls and other cleaning appliances shall not be used.
　　B. Name: Plate sterilization technology and equipment
　　The key component of plate sterilization equipment is plate heat exchanger, which is composed of many stamped sheet metal. In the production of dairy products, juice drinks, cool drinks, beer and ice cream, HTST and UHT are widely used, and they can also be used for cooling.
　　Specification Model: KA 0.6C-GZ-30MJ
　　The main components of plate sterilization technology and equipment are sheet heat exchanger, boundary plate, guide rod, compression plate, support, compression screw, sealing gasket and temperature control device.
　　Working Principle: Plate heat exchanger is composed of many stainless steel sheets overlapped and combined together. There are rubber gaskets between the plate and the plate to ensure sealing and make a certain gap between the two plates. After compaction, the corner holes on all plates form a fluid passage. The cold and hot fluids flow on both sides of the heat transfer plate and exchange heat to heat the material to sterilize temperature.
　　Operational specifications:
　　(1) assembly. Clean the heat exchanger plate, check whether the sealing washer is in good condition, hang in sequence, place the holes in the right direction, then rotate the handle, edge blank holder correction, press the plate evenly to make it neat and well sealed.
　　(2) Pressure test and disinfection. Pass in the water of rated pressure, carefully check whether there is leakage, then release the water, pass in the high pressure steam, disinfect for 5 minutes.
　　(3) operation. The hot and cold fluids are fed into the heat exchanger separately to control the pressure and flow rate. At the beginning, the temperature of the output fluid may not meet the requirements. When the temperature is normal, it can be put into operation.
　　(4) parking. First stop the flow of high temperature fluid, then stop the flow of low temperature fluid until the fluid in the heat exchanger is exhausted.
　　(5) cleaning. The fluids used for heat exchange have different properties, and their cleaning processes are also different. For the production of dairy products, alkali, acid and hot water are generally used for cleaning.
　　Use precautions:
　　(1) The equipment must be adjusted, otherwise it will affect the heating of the feed liquid and cause coking.
　　(2) Check the shape and cleaning condition of each heat transfer plate regularly, and check the sealing performance of each sealing gasket. If aging, all the gaskets should be replaced in time.
　　(3) When compacting heat transfer plate, the degree of compaction should be uniform and appropriate so as not to leak. If too much force is exerted, the sealing ring will easily lose its elasticity and aging.
　　(4) When replacing the washer, the back of the new washer should be wooled with fine sand paper, cleaned with organic solvent, then coated with adhesive, dried slightly, put into the tank, pressed around, and then lightly pressed.
　　(5) Each control instrument shall be operated by a special person in strict accordance with the operating rules.
　　C. Name: Fermentation Tank
　　Fermentation tank refers to the device used for microbial fermentation in industry. Its main body is the main cylinder made of stainless steel plate, its volume is 1 m3 to hundreds of m3. Strict and reasonable structure should be paid attention to in design and processing. It can withstand steam sterilization, has certain operational flexibility, minimizes internal accessories (avoid dead angle), has strong material and energy transfer performance, and can be adjusted to facilitate cleaning, reduce pollution, suitable for the production of a variety of products and reduce energy consumption.
　　Specification Model: SY-3020
　　Main components:
　　Tank: Mainly used for cultivation of fermentation bacteria, with good sealing (to prevent bacterial contamination). There is stirring slurry in the tank, which is used for stirring bottom ventilation continuously during fermentation process. There are control sensors on the top plate of the air or oxygen tank used for the growth of bacteria. The most commonly used ones are pH electrode and DO electrode, which are used to monitor fermentation in fermentation process. Variation controllers of liquid pH and DO are used to display and control fermentation conditions, etc.
　　Working principle:
　　The main components of the self-priming fermentation tank are self-priming agitator and guide wheel. The air tube is connected with the rotor. Before the rotor starts, the rotor is immersed in liquid, and then the motor is started to rotate. Because the rotor rotates at a high speed, the liquid or air is thrown to the outer edge of the impeller under the action of centrifugal force. In this process, the fluid gains energy. The faster the rotor rotates, the faster the linear speed of rotation is. The larger the kinetic energy of the fluid (which also contains gas) is, the greater the static pressure energy is when the fluid leaves the rotor, and the greater the negative pressure in the center of the rotor. Therefore, the air is continuously absorbed and thrown to the outer edge of the impeller, and the gas and liquid are evenly distributed through the stator. Because of the stirring effect of the rotor, the gas-liquid mixture flow (turbulence) forms on the outer edge of the impeller, which causes the air just leaving the impeller to split into tiny bubbles in the fermentation broth of continuous circulation, and mix, tumble and diffuse into the whole tank in the turbulent state. Therefore, the rotor has two functions of stirring and aerating at the same time.
　　Use precautions:
　　1. If air leakage occurs at the joint of intake pipe and outlet pipe, fillers should be added or replaced when the tightening joint does not solve the problem.
　　2. Pressure gauges and safety valves should be inspected regularly, and should be replaced or repaired in time if any faults occur.
　　3. When cleaning the fermenter, please brush it with a soft brush instead of scraping it with a hard tool, so as not to damage the surface of the fermenter. The supporting instruments should be checked once a year to ensure normal use.
　　4. Electrical appliances, instruments, sensors and other electrical equipment are strictly prohibited from direct contact with water and steam to prevent dampness.
　　5. When the equipment stops using, it should be cleaned in time to exhaust the residual water in the fermentation tank and pipelines. The lid of fermentation tank and hand hole screw should be loosely developed to prevent permanent deformation of sealing ring.
　　6. Operating Platform, Constant Temperature