What Is a Furnace Flue?

Flue pipe (flue pipe) is a tubular device for exhaust gas and smoke emission. Residential flue is a vertical pipe product used to exclude kitchen smoke or bathroom exhaust gas, also known as exhaust duct, ventilation duct, residential exhaust duct.

flue pipe, a duct in a chimney that sends flames and smoke to the outside space. Flue duct, a pipe product used to exclude smoke or turbid gas from the kitchen during cooking activities. Also called exhaust duct, ventilation duct,

Previously, most of the flues were

When the inlet flue gas is exhausted into the flue, it will meet the upper and lower layers of smoke. When the two air streams meet, it will form a vortex and an air curtain. This vortex and air blocking curtain will hinder the lower layer of smoke from going up. When the fire check valve is stuck with oil and fails to open, the smoke will be smoked indoors due to the obstruction of upward movement.

In order to overcome the technical problems of the above smoke and string smell, the solution adopted is to apply the principle of aerodynamic dynamic and static pressure conversion (

1. Article 6.8.2 of the "House Design Code" (GB50096-2011) requires that the exhaust duct product itself is a shaped exhaust duct product that can prevent the backflow of each layer. Article 6.8.2 of the "House Design Code GB50096-2011" also specifies that the exhaust duct product itself must have a backflow prevention structure.

2. The construction industry industry standard "Residential Kitchen and Bathroom Exhaust Duct" (JG / T194-2006) issued by the Ministry of Construction, applicable to exhaust gas ducts made of various raw materials (desulfurized aluminate cement and silicic acid) Raw materials other than salt cement must obtain relevant new material application certificates).

3. The building material industry standard "Glass Fiber Reinforced Cement Exhaust Pipe" issued by the National Development and Reform Commission (JC / T8542008) is applicable to sulphoaluminate cement and portland cement sandwiched with alkali-resistant glass fiber mesh cloth. Residential exhaust air duct. Sulfoaluminate cement and Portland cement are the raw materials for exhaust ducts with stable performance

4. Article 8.5.1 of the national standard "Code for Fire Protection in Architectural Design" (GB50016-2014) (2018 edition) stipulates that the following places or parts of the building shall be provided with smoke-proof facilities: (1) smoke-proof staircases and their front rooms; (2) Front room or shared front room of fire elevator room; (3) Front room and refuge floor (room) of evacuation aisle. For public buildings, factory buildings, warehouses and residential buildings with a building height of not more than 50m, the smokeproof stairwell's front room or shared front room meets one of the following conditions, the stairwell may not be provided with a smoke prevention system: ( 1) The front room or shared front room adopts open balconies and alcoves; (2) The front room or shared front room has openable external windows with different orientations, and the area of the openable external windows meets the area requirements for natural smoke exhaust. Article 8.5.2 stipulates that smoke exhaust facilities shall be provided in the following places or parts of the factory building or warehouse: (1) Category C production places with large personnel or combustible materials, the building area of the Category C factory building is greater than 300m², and there are often people staying or combustible Above-ground rooms with more objects; (2) Class D production workshops with a construction area of more than 5000m²; (3) Class C warehouses with an area of more than 1000m²; (4) Lengths of more than 20m in high-rise factory buildings (warehouses) with a height of more than 32m Evacuation walkways, evacuation walkways with lengths greater than 40m in other workshops (warehouses). Article 8.5.3 stipulates that smoke exhaust facilities shall be provided in the following places or parts of civil buildings: (1) Song, dance, entertainment, and entertainment venues located on the first, second, and third floors and with a building area of more than 100m²; Floor, underground or semi-underground song, dance, entertainment and entertainment venues; (2) Atrium; (3) Above-ground rooms in public buildings with a building area of more than 100m² and frequent stays; (4) Public buildings with a building area of more than 300m² There are many above-ground rooms; (5) Evacuation walkways with a length greater than 20m in the building. Article 8.5.4 stipulates that in a windowless room in an underground or semi-underground building (room) or above-ground building, when the total construction area is greater than 200m² or the construction area of a room is greater than 50m² , and there are often people staying or there are many combustibles, Set up smoke exhaust facilities. Article 12.3.3 stipulates that the mechanical smoke exhaust system and the tunnel ventilation system should be installed separately. When used together, the combined ventilation system shall have the function of quick changeover in the event of a fire, and shall meet the requirements of a mechanical smoke exhaust system. Provision 12.3.4: The mechanical smoke exhaust system installed in the tunnel shall meet the following requirements: (1) when full horizontal and semi-transverse ventilation methods are used, smoke can be discharged through the exhaust duct; (2) when vertical smoke exhaust methods are used, It should be able to quickly organize airflow and effectively exhaust smoke. The speed of exhaust smoke should be determined according to the most unfavorable fire scale in the tunnel, and the speed of longitudinal airflow should not be less than 2m / s, and should be greater than the critical wind speed. (3) The exhaust fan and the Auxiliary equipment such as dampers, mufflers, and soft joints through which the smoke flows should be able to withstand the designed tunnel fire smoke discharge temperature, and should be able to continuously operate normally at 250 ° C for no less than 1.0h. The fire resistance of the smoke exhaust pipe should not be less than 1.00h.

5. The mandatory provisions of Article 9.4.3 of the national standard "Code for Residential Buildings" (GB 50368-2005) stipulates that the installation of vertical shafts in residential buildings shall meet the following requirements: vertical shafts such as cable wells, pipeline wells, smoke exhaust ducts, and exhaust ducts. They shall be installed separately, and the wall of the shaft shall be made of non-combustible members with a fire resistance of not less than 1.00h.

6. The national standard "Engineering Technical Standards for Residential Exhaust Piping Systems (JGJ / T455-2018) makes clear provisions for the engineering design, construction and acceptance of residential kitchens, toilets and other exhaust piping systems. ^[2]

1) Design background

The heating furnaces of wellheads and depots in Tahe Oilfield, due to their internal structure, make it difficult to clean the flue. The long-term use causes the furnace system to fall, dripping water from the chimney, and tempering of the fire nozzle. The tube is cleaned.

The heating furnace of Tahe Oilfield is indirect heating with a fire-tube water jacket. Its combustion flue adopts a U-shaped structure. Therefore, after long-term operation of the heating furnace, carbon deposits are formed in the flue and furnace. The cleaning method of the factory plan is to use a heating furnace. The explosion-proof door or baffle at the end of the flue and the connection of the chimney is opened. The operator holds a long rod slightly larger than the flue of the heating furnace. The front end is fixed with a large cloth or cotton yarn. The operator extends the long rod into each flue. Inside, push and pull back and forth to achieve the purpose of clearing carbon deposits. Second, when manual cleaning fails to achieve the effect, a large-scale air compressor driven by a diesel engine is connected to the gas pipeline; manual cleaning is performed in the same way, and then the burner and the burner are removed to remove the air compressor. The gas outlet pipeline is back-purged by the furnace, and purges the carbon deposits accumulated in the U-shaped tube at the previous stage.

Because the flue is difficult to clean up, the on-site operation also uses a blasting method to perform a one-time treatment of the flue, stove, and chimney. That is, after a certain amount of natural gas is discharged, it is suddenly ignited, resulting in a small range of deflagration. The carbon deposits on the wall fall off to achieve the purpose of cleaning.

2) Reconstruction process flow chart

The blower uses the power of an electric air compressor to install a high-pressure 4-layer steel wire-wound rubber tube with a length of 6 meters and a diameter of 25 mm at its exit position, and an iron scraper with an adjustable diameter at the front end. The motor is equipped with an air switch that complies with oil field safety regulations. A 100-meter-long, 3 * 6 + 1 rubber-sheathed cable is used as a power transmission device. The base is rolled and supported by four solid rubber wheels. The outside is protected by a 2mm steel plate. It is mainly composed of motor and air compressor, cable and switchgear, purge pipe combination line, flue scraper, support and protective cover.

3) Process principle

(1) Design an air compressor that can be moved at any time by a pickup truck.

(2) Processing a set of cylindrical scraper that matches the flue of each type of heating furnace.

(3) Machining a set of pipeline connection devices matching air compressors and scrapers.

(4) Install a set of protection devices and cables and switchgear required for the power system to the air compressor.

(5) When working, connect the motor cable of the flue sweeper to the on-site secondary cabinet or pumping cabinet.

(6) Connect the purging line of the flue machine, first connect the high-pressure hose, connect the iron pipe with a certain length of wire buckle according to the model of the heating furnace, and finally connect the high-pressure hose with a scraper head of 50cm with the same diameter as the flue of the heating furnace.

(7) Remove the burner of the heating furnace, open the explosion-proof door of the heating furnace, and then pour the purge tube into the smoke tube in the flue. Activate the switch, and then scrape back and forth according to the amount of dust in the flue. Go deep into the other side of the pipe and clean it until no carbon deposits are discharged before proceeding to the next pipe. The purge machine only needs two people to cooperate with the operation. It can be cleaned in a short time, and it is completely clean. It does not need to be cleaned repeatedly. A reasonable cleaning cycle can be formulated according to the operating status of the heating furnace. ^[4]