Throttle valve is one of the important parts in the cold storage system, helping to regulate the amount of refrigerant to maintain a stable temperature. Proper installation and adjustment of the expansion valve not only ensures the performance of the cold storage but also helps save energy and prolong the life of the device. In this article, Tan Long will guide you how to adjust cold storage throttle valve accurately and efficiently, helping the cooling system operate optimally.
What is a thermal expansion valve?
Throttle valve The heat has the task of reducing the pressure and temperature of the medium as it passes through, helping refrigeration system reach the required temperature. Thermal expansion valve Works by receiving temperature signals from the refrigerant after leaving the evaporator and automatically adjusting the valve opening to regulate cooling capacity.
Throttle valve commonly used in industrial cold storage, refrigeration systems and are often imported from reputable manufacturers. There are two types The thermal expansion valve is a balancing valve. inside and outside balance valve.
Structure and operating principle of thermal expansion valve
Internal thermal expansion valve
Often used in small capacity refrigeration system, where the evaporator has little pressure loss.
Working principle: Refrigerant passes through the valve, reducing pressure and temperature. The temperature after leaving the evaporator will adjust the valve opening to maintain the appropriate temperature in the cold room.
External thermal expansion valve
For use with large capacity refrigeration system, where there is a large pressure loss after the evaporator.
Working principle: The external balancing valve regulates the pressure at the evaporator outlet, helping to maintain stable cooling performance, prevent overheating and protect the system.
Balanced throttle valve In addition to helping overcome performance problems in large capacity refrigeration systems, ensuring the system operates more efficiently and durably.
Classification of common cold storage expansion valves today
Simple throttle
This is the most basic type of valve, usually consisting of a small piece of pipe with a cross-section of 0.4-5mm, length 0.4-0.8mm, twisted to reduce area. They are usually made of copper or copper alloy, with protective coating for increased durability. This type of valve is popular in small refrigeration system like air conditioner and home refrigerator, due to its simple and efficient structure.
Thermal expansion valve
This type of valve regulates the refrigerant flow based on the temperature change at the measuring point, allowing for more precise temperature control. Thermostatic expansion valves are widely used in industrial refrigeration system and medium and large scale civil, thanks to the ability to automatically adjust according to temperature.
Electronic expansion valve
This is the most advanced type of valve, using multiple measuring signals in the system to regulate flow. refrigerant. Electronic throttle valve has complex structure, allows more precise and automatic adjustment, often used in cooling system Large, modern, high performance and energy saving.
How to adjust the cold storage throttle valve correctly and most accurately
Before learning how to adjust cold storage throttle valve, you need to understand the concept of “superheat” (overheating). Superheat is the temperature difference between when the refrigerant leaves the evaporator (T1) and when it starts to evaporate in the evaporator (T0). If the superheat is too high, the final temperature of the compression process will increase, which may damage the lubricating oil and affect system performance. Therefore, superheat should be maintained within the range 5°C to 7°C.
How to adjust cold storage throttle valve follow these steps:
- T1 temperature measurement: Measure the outlet temperature of the evaporator, near the thermocouple.
- Measure Po pressure: Use a pressure gauge to measure the pressure Po near the thermocouple or at the compressor suction.
- Find temperature T0: Consult the parameter table to find the evaporation temperature T0 from the pressure Po.
- Superheat calculation: Superheat = T1 – T0. If superheat is less than 5°C, the throttle valve should be closed. If it is greater than 7°C, the valve should be opened more.
- Monitor and adjust: Check back after an hour and repeat the process if necessary.
Note: The number of valve adjustment turns depends on the valve type. For example, TE2 valve need adjustment 4°C/cycle, while TE5 or TE12 is 0.5°C/cycle. You can also use the app Ref Tools for more precise adjustment after measuring the parameters T1, Po, and T0.
Things to know when adjusting the throttle valve
To keep the machine running smoothly and protect the throttle valve and other parts, you need to note the following:
- Select the appropriate valve: Make sure the throttle valve is compatible with your machine model.
- Cleaning and maintenance: When not in use, clean the valve thoroughly and store it carefully.
- Avoid damp places: Do not leave the valve in a damp or wet place to avoid rust.
- Continuous operation limitations: Avoid operating the machine continuously for long periods of time to protect the machine's life.
- Regular check: Regularly check valves to detect and handle problems promptly. Ensure oil source is clean and free of dirt.
Through this article, Tan Long introduced the structure, operating principles and how to adjust cold storage throttle valve. Hope the information in this article will be useful to you. If you have any questions about how to adjust cold storage throttle valve or industrial cold storage, please contact us via hotline: (+84) 933357058 – Mr. Thinh.
