What Is a Steel Flue?

Gas combustion equipment with closed furnaces, such as water heaters, boilers or some industrial furnaces, must be exhausted in a timely manner. ^[1] Exhaust duct refers to the channel that eliminates the smoke generated by the coal burning stove. ^[2]

Exhaust Flue Product Classification

(1) According to the structure of the flue gas duct, the flue gas duct is divided into a main branch (PYZ) type that shares the main flue with a branch flue and a single setup (PYD) for each household type.

(2) According to the length of each section, the smoke exhaust duct is divided into three types of 0.9, 1.0m and the height (H) as the length, and the codes are 09; 10; 27; 28; 29; 30.

(3) The exhaust duct is divided into three types according to the direction of the smoke inlet, and its code is L, R, F. L means that the smoke inlet is on the left, R means that the smoke inlet is on the right, and F means that the smoke inlet is on the front. Without this symbol, there is no such item. Smoke inlet

Visually inspect the inner and outer surfaces of the exhaust duct for exposed bars, honeycombs, hollow drums, and collapse.

Each dimension of the exhaust duct shall be measured with a steel tape measure with an accuracy of 1 mm.

The lateral bending of the flue shall be measured by a special straightness deviation measuring instrument or a metal ruler or wooden ruler with a length not less than the length of the flue.

The verticality of the two sides and sides of the exhaust duct is measured with a curved ruler.

The crack should be measured with a magnifying glass no less than 20 times. ^[3]

Due to the high temperature of the fire, the comprehensive performance of the material of the tunnel structure system is severely reduced, which will inevitably lead to the serious reduction of the bearing capacity and high temperature safety performance of the flue structure system, and the working state of the system will change accordingly.

Although the structural design of the top of the flue duct and the design of the anchored connection of the planted bars have been successfully applied in foreign tunnels for a long time, there are still many risk factors. For example, the Pufende Mountain Highway Tunnel in Austria has a total length of 6.75 km. It is designed to use full lateral ventilation. During a fire, the air is exhausted through the exhaust vent. The air duct and the exhaust duct are divided by a middle partition. The concrete structure adopts the connection method of cast-in-situ "colt" with the lining. In 1995, a fire broke out in a rear-end collision between a large truck and a small car. The fire lasted for nearly 1 hour and directly injured 4 people. The temperature near the source of the fire in the tunnel reached 1 000 ° C for a time, causing up to 25 The top partition of m collapsed, so it can be seen that the structure needs to be protected by fire protection.

Under the action of fire load, the top diaphragm deformed completely under the normal temperature. This is because under the action of fire, the top partition plate generates a very uneven temperature field along the cross-section height direction. Under the effect of thermal stress, on the one hand, the top bulkhead will have uneven expansion and deformation; on the other hand, the structural performance of the material will be deteriorated at high temperatures, and the structural rigidity will be reduced, which will increase the top bulkhead deformation. Due to the restriction of geometric deformation at the end of the top bulkhead, the axial force of the top bulkhead under fire is greatly increased. It is well known that the higher the temperature near the surface of the top partition, the faster the top partition will be damaged by compression or even collapsed. The experiment reached the following conclusions:

(1) In the case of a tunnel fire, the maximum temperature of the flue gas on the surface of the top bulkhead can reach 600 ~ 1 000 , and when the smoke exhaust valve is opened for centralized smoke exhaust, the top bulkhead structure is on both sides.

(2) In the case of a fire for 2 hours, the critical temperature at which the top diaphragm is damaged by compression is 650 ~ 700 :

(3) According to the results of FDS analysis, under the condition that the flue gas cannot be discharged through the exhaust duct, the temperature of the entire lower surface of the top partition can be as high as 900 , and the damage thickness of the concrete accounts for about half of the design thickness of the top partition. The force is severely reduced, which is likely to cause the top bulkhead to collapse.

(4) In a fire, within 10 m of the fire source as the center, the concrete boundary temperature of the lower surface of the top bulkhead is about 1 000 ° C, and the structural temperature is about 900 ° C during 2 hours of the fire, and the damage thickness is about 8-9 cm, will cause the top bulkhead structure to collapse. ^[4]

Everyone is concerned about the problem that if the exhaust pipe is directly discharged from the public exhaust pipe, there may be a trouble: skewer. That is to say, the taste of other kitchens will be skewed into their own homes. Many people have this experience, so some students have considered opening a different mouth to exhaust smoke directly from the beginning of the decoration, and the exhaust outlet of the public exhaust duct Blocked.

This really solves the problem of skewers, but it also brings a new problem: the smoke outlets of each house are different, the styles are different, and the colors and patterns are various. The whole community will look very uncoordinated and difficult to see in the future. In order to keep the whole neat and beautiful, I will give you a suggestion for your reference. as follows:

The public flue is still used for exhausting smoke. A device called a flapper valve is installed at the smoke exhaust port of the house. When the cooker hood is turned on, the flapper valve is opened to discharge the smoke normally. After cooking, close the flapper valve and exhaust the smoke at home. The tunnel and the public flue are now separated.

Note: The flapper valve is a device often used in the factory, and it is rarely used in home decoration. So many people are not familiar with it. In fact, this is a very simple device. It is very cheap by itself (I have nt bought it, but it is also expected to Just tens of dollars), and it is something that won't break all year round.

The smoke-proof flue exhaust duct relates to a flue exhaust duct installed in a wall of a civil house, and is composed of a flue duct and a flue joint. The flue joint has a rectangular parallelepiped shape, and a square flue hole is opened in the vertical direction at the inner end, and a chimney hole and an ash hole are vertically opened at the upper and lower portions of the outer end, respectively. The flue is made up of two or more sections of flue pipes connected end to end. The flue pipe is a square long pipe with two ends open, the lower end is a flat mouth, and the upper end is provided with a square slot that matches the lower end of the previous section of the flue pipe. The utility model has the advantages of convenient and reliable installation, strict interface, and can effectively prevent string smoke. In addition to being widely used as a smoke exhaust duct for civil houses, it can also be used as an air duct.