How does the pasteurized yogurt processing equipment achieve temperature control? The most important thing in the process of pasteurization is the control of temperature. If the temperature is too low, the sterilization is not complete, and if it is too high, it will destroy the nutrients. Therefore, the temperature requirements of the pasteurization processing equipment are very high.
Constant pasteurization temperature is maintained by a temperature controller that works on the steam regulating valve. Any drop in product temperature will be detected by a sensor on the product line before the holding tube. Then, the sensor sends this signal to the controller, and the controller will open the steam regulating valve to provide more steam to the water, which can increase the temperature of the circulating water and prevent the product temperature from falling.
The length and volume of the holding tube are calculated based on the known holding time, the hourly production capacity of the device, and the size of the tube (generally refers to the tube of the pasteurization device). The dimensions of the holding tube are given in Section 6.1. Generally, the holding tube should be covered with a stainless steel cover to prevent people from being burned when touching and also to prevent heat radiation.
It must be ensured that the milk has undergone sufficient pasteurization before leaving the plate heat exchanger. If the sterilization temperature drops below 72 ° C, the non-pasteurized milk must be separated from the pasteurized milk. In order to achieve this, a temperature sensor and a liquid flow steering valve are installed downstream of the holding tube. If the temperature sensor detects that the milk passing through it is not sufficiently heated, the steering valve will return the non-pasteurized milk back Balance trough.
As mentioned above, the product is mainly cooled by heat recovery and heat exchange. The greater efficiency of heat recovery is about 94-95%, which means that the lower temperature obtained from heat recovery cooling is about 8-9 ° C. The milk is cooled to 4 ° C for storage and requires a cooling medium of about 2 ° C. If the final temperature is higher than 3-4 ° C, only ice water is required. To achieve lower temperatures, it is necessary to use saline or alcohol solutions to prevent the danger of freezing the cooling medium.
The cooling medium is circulated from the refrigeration equipment of the dairy factory to the cold-required parts as shown in Figure 7.4. The flow rate of the cooling medium entering the pasteurizer should be controlled to maintain a constant product outlet temperature. This can be achieved through a regulation cycle. This cycle includes a temperature sensor on the product outlet line, a temperature controller on the control board, and a regulating valve on the cooling medium inlet line. The controller changes the position of the regulating valve based on the signal from the sensor.
The signal from the sensor is directly proportional to the temperature of the product from the pasteurizer. This signal is usually connected to a temperature recorder on the control panel and recorded on a recording paper. The pasteurization temperature and the opening and closing of the steering valve were also recorded.
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