Throttle valve Air conditioner is an important part of the cooling system, responsible for creating cold air in the cold block. This article, Tan Long will explore with you the structure and function of throttle valve air conditioner and how to handle it when this part has problems. Let's Tan Long Find out more!
What is a throttle valve?
Throttle valve is a type of valve used to regulate the amount of fluid flowing through a hydraulic system. Its main function is to control the speed and pressure of the fluid. As the fluid passes through the valve, the speed increases, then decreases, and the pressure increases but does not return to its original level, causing the density of the fluid to change due to the pressure change.
Classification of common throttle valves
Simple throttle, or throttle tube, manual throttle
Throttle valve Simply, throttle tubes and manual throttle valves are the most basic types of valves, usually consisting of a piece of pipe with small cross section (0.4-5mm), long (0.4-0.8mm), are twisted to reduce the area. They are usually made of copper or copper alloy and are shielded for increased durability. This type of valve is often used in small refrigeration systems such as air conditioners and household refrigerators, thanks to its simplicity and efficiency in regulating flow. refrigerant.
Thermal expansion valve
Thermal expansion valve is a type of valve that operates based on temperature changes at the measuring point to regulate the flow of refrigerant passing through the valve. This structure allows the thermostatic expansion valve to adjust more accurately based on the actual temperature of the system. This type of valve is widely used in industrial refrigeration system and civil on medium and large scale, thanks to the ability to automatically adjust flow according to temperature, helping the system operate more efficiently.
Electronic expansion valve
Electronic expansion valve is the most advanced type of valve, using one or more signals measured at different locations in the refrigeration system to refrigerant flow control. The complex and high-tech structure of the electronic expansion valve allows it to adjust the flow more precisely and automatically. This type of valve is often used in large refrigeration system, modern with high technology content, ensuring optimal performance and energy saving.
Throttle valve structure
The air conditioner valve has a rather complex structure, consisting of many parts that play an important role in regulating the flow of refrigerant gas. Specifically, the main parts are:
- Valve body: This is the part that contains the internal components of the valve, usually in the shape of a cylinder or rectangular box.
- Input and output: The two valve connectors have different sizes and thread types depending on the valve type, ensuring tight connection with other parts in the refrigeration system.
- Valve disc: This part is responsible for blocking the refrigerant gas and can move up and down to adjust the flow of refrigerant gas passing through the valve.
- Spring: This part helps push the valve disc up and down, with different stiffness depending on the valve type to ensure accuracy in flow regulation.
- Control: This part receives signals from temperature or pressure sensors to adjust the opening of the valve disc, ensuring the system operates stably and efficiently.
Main operating principle of throttle valve
The throttle valve operates on the following principle:
- When the air conditioner is running, refrigerant from the compressor flows into the valve through the inlet.
- The valve disc opens partially to allow refrigerant to flow, depending on the stiffness of the spring and the signal from the controller.
- The refrigerant flows out of the valve through the outlet at a lower pressure and flow rate than when it entered.
- The refrigerant gas continues to travel to the evaporator, where it evaporates and cools the air.
- When the ambient temperature or cooling demand changes, the controller sends a signal to adjust the valve disc opening, increasing or decreasing the refrigerant flow to maintain cooling performance.
Signs of a Throttle Valve Problem and How to Fix It
Signs of recognition
The air conditioner valve can become clogged with dirt, oil, debris, or other contaminants that have settled on the valve plate or spring. When the valve is clogged, you may notice the following signs:
- Air conditioner does not cool or cools unevenly: The system does not reach the desired temperature or heat distribution is uneven.
- Compressor is running weakly or making loud noises: The compressor is not working efficiently or is making unusually loud noises.
- The refrigerant gas pressure at the inlet and outlet of the valve is approximately equal: There is no significant pressure difference between the inlet and outlet of the valve.
- The refrigerant temperature at the valve outlet is higher than normal: The refrigerant gas does not reach the required temperature after passing through the valve, resulting in reduced cooling performance.
How to fix
If the expansion valve is only clogged and not seriously damaged, you can fix it yourself to get the air conditioner working properly again, by:
Turn off the power: Turn off the air conditioner and unplug it from the power outlet.
Check throttle valve: This determines the location and cause of the blockage.
Cleaning the valve:
- If the valve is covered with dust, rust, or dirt, use a damp cloth or cotton ball to clean the valve surface. You can also use a specialized cleaning solution to clean the inside of the valve.
- If the valve is frozen, use a hair dryer or hot water heater to thaw it.
Check and add refrigerant:
- If the valve is losing refrigerant, use a pump to replenish refrigerant in the system.
- Use a pressure gauge to check the refrigerant pressure and adjust if necessary.
Replace or repair:
If the valve is severely damaged, replace the valve or contact the service center for repair.
Select throttle valve with external balancing diaphragm
In the field cold storage, throttle valve is an important part of the system. The main task of throttle valve is the flow regulator solvent (liquid) from high pressure, high temperature area to low pressure, low evaporation temperature area. In addition, it also regulates the flow solvent to feed into the evaporator.
To manage the amount of steam with high resistance in cold storage system, External balancing throttle valve is used. Selection of suitable throttle valve depends on the following parameters:
- Evaporation temperature
- Condensing temperature
- Cooling capacity Q0
- Type of refrigerant in the refrigeration system
There are many different types of expansion valves on the market, below is an example of a Danfoss external balancing expansion valve for cold storage systems, with the following specifications:
- Refrigerant used: NH3
- Cooling capacity: Q0 = 39.6 kW
- Evaporation temperature: t0 = -28°C
- Condensing temperature: tk = 38°C
Some habits of using air conditioner to prevent damage
To protect the expansion valve as well as other parts of the air conditioner, you should apply some good usage habits to help the air conditioner operate more durably:
- Regular air conditioner cleaning: At least once every 3 months. This helps prevent valve blockage and protects your health.
- Do not let the air conditioner run continuously for too long: Let the machine rest for at least 15 minutes after every 4 hours of operation to avoid overload, overheating and loss of cold air, thereby reducing the risk of valve failure and compressor.
- Adjust the temperature appropriately: Set the temperature according to your needs and weather conditions, avoid setting it too high or too low to prevent freezing or melting, which will affect the operation of the valve and evaporator.
- Regular valve inspection and maintenance: At least once every 6 months, check and maintain to promptly detect and fix problems such as damage or blockage, ensuring the performance and life of the air conditioner.
Throttle valve is an important part of cooling system, which helps regulate the flow and pressure of refrigerant. Regular maintenance and proper use will help prolong the life and performance of the valve. Choosing the right valve for your system is important to ensure efficient operation.
