Why does the flue gas flue appear to be inverted

The construction industry is a large industry, and there are a lot of building materials used in it. When building houses, flue gas ducts are used in many places, especially in some hotels, restaurants and other places. The flue gas ducts are mainly used As far as the role of smoke exhaust, but sometimes when in use, there will be oil and smoke backflow, then what is the cause? Let's analyze the reasons for the phenomenon of oil backflow in the flue gas duct.
It is probably due to the problem of the sealing surface material: because of the different valve types, the sealing method and material requirements are different, but this problem is not taken into account in the actual operation process, and some follow-up problems have occurred. For ordinary wedge gate valves, the material, fixing method, and grinding method of the copper ring should be explained. Sometimes, before using this kind of product, those who don't know or know whether it can be used, cause problems in the process of use. The improper use of soft-seal gate valves, and the physical, chemical and hygienic testing data of the valve plate rubber lining materials show that there are some situations where this type of product is not suitable for use. Some products, especially rubber, have very high requirements for hygiene, anti-aging performance, and wear resistance. However, if they do not meet the requirements, they will have a very large impact.
I believe that after our analysis, everyone should understand the reasons for the phenomenon of oil fume backflow in the flue gas duct. When using the flue gas duct, we must consider various aspects and find a suitable method to operate. Moreover, the construction method is also very important. If the construction method is wrong, there will be a lot of follow-up effects. Of course, the more important thing is the smoke. For airway quality problems, some manufacturers sell flue gas flue at low prices, and builders purchase those cheap flue gas flue because of the low cost, but the impact on users is very large.