How does the car membrane tank (expansion tank) and what functions are performed?

Ironically, the Internet can find thousands of articles on thermostats and radiator, but few people remember about such important details in the cooling system, as the diaphragm expansion tank.The way he is visually simple design and primitive features, but its presence is very powerful for every car.Often motorists caught in cases where the engine temperature sensor provides exorbitant values.But few of us know about the causes.So today we'll talk about what are the membrane expansion tanks and how they work.

Design features

This item is a container made of plastic, equipped with special rubber hose through which the liquid is delivered, and sensors to determine its level in the tank.In addition, each tank is equipped with a through diaphragm pressure valve.Generally, it can be seen in the top cover of the container.Why is it needed?His presence is very important for each expansion tank.It throughput valve regulates pressure in the vessel at different temperatures.The coolant, as water tends to expand at high temperatures.So, if the engine is heated up to 110 degrees Celsius or more, the pressure increases significantly antifreeze.And lest there was an explosion of capacity, there is a special valve which regulates and these values.That's why when overheated motor does not need to immediately open this part - a little of what it will pop up under the influence of pressure in an unknown direction, splashed boiling antifreeze to the driver, so still and the motor is no longer cool.

How does the diaphragm expansion tank car?

When the engine is hot all its components.Accordingly, the coolant temperature also increases.And because the system is completely sealed inside it creates a critical pressure.The device cooling the engine is starting to expand and accumulate in the membrane tank excess air, which was formed when the temperature jump.Once the container is formed in a critical pressure (but not such that the container is about to explode), the valve starts to open and release the accumulated air.Gradually, the compression ratio of the liquid falls.The walls of the container, in turn, does not allow a liquid to spread or evaporate.

winter, diaphragm tank, too, plays an important role.At low temperatures, the engine cools down immediately.Together with this the pressure in the engine cooling system.To this marker was not too low (less than atmospheric) in the vessel inlet valve opens and draws air into the system.Due to this plastic container is not compressed to form tubes, and the coolant level is normal.

Conclusion As you can see, a membrane tank, despite its primitive structure, performs a very important function and plays a significant role in the life of the car.