Cold brewing, the counterpart to traditional hot brewing of coffee and tea, has been around the world for many years and is popular for its unique texture and taste. The production process of cold brew beverages is based on the principle of low-temperature extraction, that is, under vacuum condition, the boiling point of water is much lower than that of normal pressure (100°C) to brew beverages at low pressure and temperature. In addition, the nitrogen-enriched drinks that have appeared in recent years are filled with high-pressure nitrogen after cold brewing, which has greatly changed the texture, taste and visual effects of drinks such as coffee and tea. (Figure 1 Schematic diagram of vacuum pressure automatic control solution) The solution shown in Figure 1 can control the vacuum degree and high pressure of the beverage container separately, in which a vacuum gauge and a pressure gauge are used to measure the vacuum degree in the beverage container and the nitrogen pressure during nitrogen filling respectively. In the above solution, two closed-loop control loops are designed for vacuum degree and pressure control respectively. In order to reduce cost and volume, the common part of these two closed-loop loops is the inlet and outlet valves and controllers, and the independent part is vacuum gauges and pressure gauges. (1) Automatic control of vacuum degree In the process of controlling the vacuum degree, first turn on the vacuum pump and the high-pressure air source. At this time, the high-pressure air source may not be connected, or the normal pressure atmosphere may be used. When the gas outlet rate of the container is greater than air intake rate, a low-pressure vacuum will naturally form in the container state. Then the controller makes a comparison according to the set vacuum value or program and the collected vacuum gauge signal. The controller outputs the control signal according to the PID control algorithm according to the difference after comparison, and adjusts the opening of air intake valve and exhaust valve at the same time. The measured value of vacuum gauge quickly approaches and equals the set value, thereby realizing the dynamic adjustment of vacuum degree control. It should be noted that because different coffees and teas have different requirements on the vacuum degree and change speed during the low-temperature brewing process, the controller must have a programmable design function, and the valve needs to have a faster adjustment speed. (2) Automatic control of nitrogen filling high pressure After completing the vacuum degree control process and the low-temperature brewing process, the nitrogen filling process and high-pressure control process can be directly carried out, and vacuum pump can be turned off at this time. When the air outlet rate of container is lower than air intake rate, a high pressure state will naturally form in the airtight beverage container. Similarly, the controller compares the collected pressure gauge signals according to the set pressure value or program. The controller outputs the control signal according to PID control algorithm according to the difference after comparison, and simultaneously adjusts the opening of air intake valve and the exhaust valve, so that the measured value of pressure gauge quickly approaches and equals the set value, thereby realizing the dynamics of high pressure control. It should also be noted that since different coffees and teas have different requirements on the pressure and change speed during the nitrogen filling process, the controller must also have a programmable design function, and the valve must also have a faster adjustment speed. In order to reach the engineering realization of design content of solution shown in Figure 1, according to the above vacuum pressure control requirements, a corresponding vacuum pressure control system is configured, and the specific structure is shown in Figure 2. (Figure 2 Schematic diagram of vacuum pressure automatic control system) KaoLu's QKL-B4H Proportional Pressure Regulator is a device used to maintain or control the pressure of a fluid (such as gas or liquid) within a desired range. It is commonly used in industrial and manufacturing processes where maintaining a constant pressure is critical to ensuring quality and consistency in the end product. KaoLu's QKL-B4H Proportional Pressure Regulator features high speed, high accuracy 0.05% F.S , and high resolution 1kPa, and most importantly ultra-stable at target pressure. Customers have used our electronic controller to replace expensive dekstop pressure controller (consult for customised spec). If you're interested in KaoLu's QKL-B4H Proportional Pressure Regulator, please contact us!