Part 1: Understand the problems and types of residential flue before installation.
Flue is an important part of residential ventilation system. The Code for Residential Design issued by Ministry of Construction 1999 regulates the design of flue. However, there are still problems in the design of smokeless corridors in many buildings, and smoking, odor and cross-pollution in community houses are serious.
First, the reasons for the poor flue in the big kitchen
The General Principles for the Design of Civil Buildings stipulates that the height of the flue protruding from the roof should not be less than 0.6m However, the implementation of this provision is different in some places. Some houses with flues are designed as single flue type, which is easy to cause oil fume backflow and odor. In addition, in some buildings, in order to increase the kitchen area, the cross-sectional area of vertical flue is reduced, and there is no mechanical smoke exhaust device, which makes the flow of smoke exhaust system very small and leads to poor smoke exhaust.
Second, understand the classification of residential flue.
At present, residential flues are generally divided into single flue type, primary and secondary flue type, variable pressure type and check valve type.
Single flue type: it consists of a simple rectangular smoke pipe, which passes through all floors of the house vertically. Each floor of the house has an air inlet connected to the range hood, and the bottom floor is supplemented by an air outlet. Its principle is that under the push of the range hood, the smoke from each floor will be discharged into the flue, and due to the effect of smoke temperature, rising buoyancy will be generated in the flue, and the smoke will be discharged from the air outlet of the roof.
Primary and secondary flue: The primary and secondary flue consists of two rectangular flue pipes with parallel sections, which vertically pass through all floors. The secondary flue is provided with an air inlet connected with the range hood on each floor of the house, and the secondary flue joins the main flue at a certain distance from the air inlet, and the bottom of the main flue is provided with an air outlet. The principle is that the smoke is pushed into the secondary flue through the range hood. At the temperature of the smoke, the smoke rises a certain distance by the driving force and buoyancy of the range hood, then enters the main flue and is discharged from the roof.
Variable pressure type: each layer of flue is made into different cross-sectional forms, the lower flue is exhausted through the primary and secondary flue, and the flue near the roof is used as a single flue to directly discharge the oil smoke into the flue. Its purpose is to change the cross-sectional form of flue as much as possible, make use of various physical laws of flue gas flow, keep the airflow moving upwards, and prevent flue gas from flowing backwards and crossing each other to the greatest extent.
Non-return valve type: The non-return valve type flue is to install a composite non-return valve with the interface function of the range hood at the air inlet of each layer of the single-pipe flue, so as to force the flue gas to move in one direction, thus solving the problem of cross-connection of flue gas, but this will slightly affect the smoke exhaust effect of the range hood.
Part II: Matters needing attention in correctly installing kitchen flue.
Some owners are worried that the flue at home smells bad, and they don't know why. Sometimes this is a problem left over from construction mistakes.
So what problems should the owner pay attention to during construction? First, the auxiliary flue must be preserved.
Every kitchen has a flue, and at the same time, the flue also has the main and auxiliary points. The main flue runs through the whole building and the auxiliary flue is relatively independent. Generally, the lampblack at home will enter the auxiliary flue first, and then enter the main flue through the small holes in the partition.
This can ensure that the fumes of every household are isolated. However, if the auxiliary flue is directly connected with the main flue, it will lead to the phenomenon of backward smoke or cross smoke due to too low pressure. Second, the construction details should pay attention to the problem
First of all, it is very important to choose the installation position of the range hood. The shorter the pipe, the better. Some owners will pull the pipe longer for the sake of beauty. After turning off the range hood in this way, there will be a lot of oil smoke in the pipeline that can't be discharged and then poured back indoors. In addition, in order not to destroy the original main and auxiliary flue, its opening direction cannot be changed at will, and it must be drilled in the auxiliary flue.
Third, pay attention to safety when opening the window to smoke.
In order to avoid the problem of smoke crosstalk, some owners gave up the original flue and directly opened holes in the windows to smoke. This is ok, but there are a few points to pay attention to.
First of all, before opening a hole in a window or wall, it must be approved by the property; Secondly, pay attention to safety issues,
Generally, the end of the exhaust pipe is metal. If the hole is too small, metal heat transfer may cause the glass to burst and hurt pedestrians. Moreover, the smoke exhaust pipe leads to the window, and the strong north wind blowing on the face will lead to the backflow of oil smoke. It is best to extend the pipeline and nest it downward, so as to prevent rainwater from flowing into the pipeline when it rains, and to keep the windshield out. Four, check valve door often change.
If the auxiliary flue has been removed, or it is necessary to better prevent the flue gas from falling back, then use the flue check valve. In general, the function of the check valve of the range hood is not obvious, but installing the check valve in the flue can protect the range hood, so that the flue gas in the flue will not flow back to the pipeline and the range hood. However, after installing the check valve, it should be cleaned regularly, otherwise it will make the check valve open and lose its function. It is best to replace the flue check valve every two years or so.
Part III: Analysis of the causes of unreasonable design and installation of exhaust duct.
The unreasonable design and installation of kitchen smoke exhaust pipeline often leads to poor smoke exhaust in the kitchen, which directly affects the use of lampblack purifier. The main reasons are as follows:
First, the ventilation area of the main smoke exhaust pipeline is not enough
According to the engineering experience, the wind speed in the main smoke exhaust pipe should not exceed 15m/s, otherwise the smoke exhaust system will be easily blocked after running for a period of time. In the operation practice of oil fume purifier, most cases are caused by insufficient ventilation area of smoke exhaust pipeline, and the gas flow in the pipeline is above15m/s.
Second, the cross-sectional area of the pipeline becomes smaller.
Because the smoke exhaust pipeline passes through the building beam, the ventilation cross-sectional area of the pipeline becomes smaller, and the resistance on the cross-section increases, resulting in poor airflow.
Third, the exhaust pipe accumulates after use.
When the smoke exhaust pipe passes through the building beam or avoids other equipment pipes, a section of smoke exhaust pipe will be lower than the plane of the whole smoke exhaust pipe. After a period of use, the oil-water mixture will accumulate in the lower section of the smoke exhaust pipeline, which will directly affect the smooth smoke exhaust.
Fourth, the low-level smoke exhaust is not smooth.
Kitchen fumes from different floors are discharged through the same main pipe. The kitchen near the exit has a good smoke exhaust effect, and the kitchen on the lower floor is not smooth.
Verb (abbreviation of verb) suggests to equip with an exhaust fan.
For kitchens with large oil fume, it is recommended to equip them with exhaust fans. There are three commonly used smoke exhaust fans: axial fan, fan main casing and centrifugal fan.
The unreasonable design and installation of kitchen smoke exhaust pipeline often leads to poor smoke exhaust in the kitchen, which directly affects the use of lampblack purifier. The main reasons are as follows:
First, the ventilation area of the main smoke exhaust pipeline is not enough
According to the engineering experience, the wind speed in the main smoke exhaust pipe should not exceed 15m/s, otherwise the smoke exhaust system will be easily blocked after running for a period of time. In the operation practice of oil fume purifier, most cases are caused by insufficient ventilation area of smoke exhaust pipeline, and the gas flow in the pipeline is above15m/s.
Second, the cross-sectional area of the pipeline becomes smaller.
Because the smoke exhaust pipeline passes through the building beam, the ventilation cross-sectional area of the pipeline becomes smaller, and the resistance on the cross-section increases, resulting in poor airflow.
Third, the exhaust pipe accumulates after use.
When the smoke exhaust pipe passes through the building beam or avoids other equipment pipes, a section of smoke exhaust pipe will be lower than the plane of the whole smoke exhaust pipe. After a period of use, the oil-water mixture will accumulate in the lower section of the smoke exhaust pipeline, which will directly affect the smooth smoke exhaust.
Fourth, the low-level smoke exhaust is not smooth.
Kitchen fumes from different floors are discharged through the same main pipe. The kitchen near the exit has a good smoke exhaust effect, and the kitchen on the lower floor is not smooth.
Verb (abbreviation of verb) suggests to equip with an exhaust fan.
For kitchens with large oil fume, it is recommended to equip them with exhaust fans. There are three commonly used smoke exhaust fans: axial fan, fan main casing and centrifugal fan.