The flue pipe is a tubular device for exhaust gas and smoke emission, and the residential flue is used for exhaustkitchenFlue gas orTOILETThe vertical pipe products of waste gas are also called exhaust ducts, ventilation ducts and residential exhaust ducts.
flue pipe，chimneyA duct in which flame and smoke are sent to the outer space.A flue is a pipe product used to remove smoke from kitchen cooking activities or turbid gas from toilets.Also called exhaust duct, ventilation ductResidential exhaust duct。Residential flue is the main part of the exhaust pipe system shared by kitchen and toilet.[1]
Since the national standard《Residential Building Code》、《Code for Fire Protection Design of Buildings》Such mandatory provisions stipulate that the fire resistance limit of the flue in residential buildings should not be less than 1.00h. Since it is difficult for the cement prefabricated flue to reach the requirement that the fire resistance limit should not be less than 1.0h, in order to prevent the accumulation of oil dirt in the residential flue from becoming a fire hazard for a long time, the flue is mostly made of high-strength glass magnesium refractory flue plates by mechanized assemblyHigh strength fire-resistant smoke exhaust ductThe variable pressure gas extraction component shall be set inside the flue, and the type inspection must be carried out according to the national standard Fire Resistance Test Method for Ventilation Ducts GB/T17428-2009, and the fire resistance limit shall be more than 1.0h;High strength fire-resistant smoke exhaust duct has the characteristics of light deadweight, high strength, no deformation, good fire-resistant performance, strong resistance to flexible impact, easy installation, good sound insulation performance, and not easy to damage.It is widely used in kitchen exhaust and toilet exhaust of residential buildings and public buildings.[1]
Application principle
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When the flue gas at the air inlet is discharged into the flue, it will meet the flue gas discharged upward from the lower layer, and the two streams of air will meet to form a vortex and air curtain. The vortex and air blocking curtain will hinder the upward movement of the flue gas at the lower layer. Once the fire check valve is stuck by oil stains and fails to open, the flue gas will flow into the room due to the upward movement obstruction
In order to overcome the above technical problems of smoke and smell, the solution is to use the dynamic static pressure conversion principle of aerodynamics（Bernoulli theorem）, byJiangsu Ziwei Construction Technology Research InstituteThe developed combined variable pressure fire-resistant smoke exhaust duct is equipped with a patented variable pressure check component for air extraction and accelerated airflow in the flue, so that the flue gas can complete the dynamic static pressure conversion at a specific location, so that the exhaust outlet of the kitchen or toilet where the smoke exhauster cannot be turned on is in a negative pressure state, and the principle of Bernoulli's theorem is used to form a suction force, so as to eliminate vortex and air blockage curtain,Solve the problem of gas and smell passing through the flue.This product can effectively solve the problems of gas vortex, gas curtain blockage, smoke backflow and smoke smell, meet the needs of residential engineering construction, and has the functions of smoke prevention, backflow prevention, fire resistance and fire prevention, reaching the leading level of similar products in China.This achievement was listed as the national construction industry scientific and technological achievements promotion project in 2012.[1]
Current standards
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1、《Code for residential design》Article 6.8.2 of (GB50096-2011) requires that the exhaust duct product itself is a stereotyped exhaust duct product that can prevent backflow of all layers.Article 6.8.2 of Code for Design of Residential Buildings GB50096-2011 also specifies that the exhaust duct product itself must have a backflow prevention structure.
2. The industrial standard of construction industry, Exhaust Duct of Residential Kitchen and Toilet (JG/T194-2006) issued by the Ministry of Construction is applicable to exhaust ducts made of various raw materials (exceptsulphoaluminate cement andportland cement Other raw materials must obtain relevant new material application certificates).
3、National Development and Reform CommissionThe issued building materials industry standard "Glass fiber reinforced cement exhaust pipe" (JC/T854-2008) is applicable to the use of sulphoaluminate cement and Portland cementAlkali resistant glass fiberResidential smoke exhaust duct made of mesh.Sulphoaluminate cement and Portland cement are exhaust channel raw materials with stable performance.
4. National standards《Code for Fire Protection Design of Buildings》Article 8.5.1 of (GB50016-2014) (2018 Edition) stipulates that the following places or parts of the building shall be equipped with smoke prevention facilities: (1) smoke prevention staircase and its antechamber;(2) Front room of fire elevator room or shared front room;(3) The front room and refuge floor (room) of the refuge corridor.For public buildings, factory buildings, warehouses and residential buildings with a building height of no more than 50m and a building height of no more than 100m, when the front room or shared front room of the smoke prevention staircase meets one of the following conditions, the staircase may not be equipped with a smoke prevention system: (1) The front room or shared front room adopts open balcony and concave corridor;(2) The front room or shared front room has openable external windows with different orientations, and the area of openable external windows meets the area requirements of natural smoke vents.Article 8.5.2 stipulates that the following places or parts of the plant or warehouse shall be equipped with smoke exhaust facilities:;(2) Class D production workshop with a building area of more than 5000m2;(3) Class C warehouse with an area of more than 1000m ²;(4) Evacuation walkways with a length of more than 20 m in high-rise buildings (warehouses) with a height of more than 32 m, and evacuation walkways with a length of more than 40 m in other buildings (warehouses).Article 8.5.3 stipulates that the following places or parts of civil buildings shall be equipped with smoke exhaust facilities: (1) song and dance entertainment screening and entertainment venues located on the first, second and third floors with a building area of more than 100m ², and song and dance entertainment screening and entertainment venues located on the fourth floor or above, underground or semi underground;(2) Atrium;(3) Above ground rooms with a building area of more than 100m ² and frequent people staying in public buildings;(4) Above ground rooms with a building area of more than 300m2 and more combustibles in public buildings;(5) Evacuation walkways longer than 20m in the building.Article 8.5.4 stipulates that when the total building area is more than 200m ² or one room is builtWhen the building area is more than 50m ², and people often stay or there are many combustibles, smoke exhaust facilities should be set.Article 12.3.3 stipulates that mechanical smoke exhaust system and tunnel ventilation system should be set separately.In case of shared use, the shared ventilation system shall have the function of rapid conversion in case of fire, and shall meet the requirements of mechanical smoke exhaust system.According to 12.3.4, the mechanical smoke exhaust system set in the tunnel shall meet the following requirements: (1) When full transverse and semi transverse ventilation modes are adopted, smoke can be discharged through the exhaust duct;(2) When the longitudinal smoke exhaust mode is adopted, it shall be able to quickly organize air flow and effectively smoke exhaust. The smoke exhaust wind speed shall be determined according to the most unfavorable fire scale in the tunnel, and the longitudinal air flow speed shall not be less than 2m/s and shall be greater than the critical wind speed;（3）Smoke exhaust fanThe auxiliary equipment such as air valve, muffler and soft connector through which the smoke flows shall be able to withstand the designed tunnel fire smoke emission temperature, and shall be able to operate continuously and normally at 250 ℃ for no less than 1.0h.The fire resistance limit of smoke exhaust pipe shall not be less than 1.00h.
5. National standards《Residential Building Code》Article 9.4.3 of (GB 50368-2005) stipulates that the setting of shafts in residential buildings shall meet the following requirements: cable shafts, pipe shafts, smoke exhaust ducts, exhaust ducts and other shafts shall be set independently, and the shaft walls shall be made of non combustible components with a fire resistance rating of not less than 1.00 h.
6. The national standard Technical Standard for Residential Exhaust Pipe System Engineering (JGJ/T455-2018) clearly stipulates the design, construction and acceptance of exhaust pipe system engineering for residential kitchens, toilets and the like.[2]
construction technology
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technological process
(1) During the construction of the main structure, the ventilation flue shall be reserved according to the position of the design drawingHolesThe size of the hole is 50~80mm more than the peripheral size of the component.The reinforcement in the reserved holes shall be reserved at the same time.
(2) Before installation, hang a plumb line from the hole on the top floor according to the size of the ventilation flue to ensure the verticality of the flue during installation.
(3) When installing on the first floor, first use 1:2cement mortarLevel the ground.After the first pipe socket is grouted, pour C20 concrete about 40cm high into the pipe;After the final setting of concrete, the upper ventilation flue shall be installed.
(4) The lower opening of the connector shall be grouted at the upper opening of the lower flue diaphragm, and its four sides shall also be grouted.The ventilation flue shall be supported by layers.Construction method: after the upper and lower pipes are aligned with the grout, the interface of the upper and lower ventilation flue is generally located at the floor, so the Ф 12 rebar is welded at the embedded steel plate at the root of the pipe and welded with the reserved rebar of the hole, which is supported on the floor base.
(5) The joint surface of the upper and lower sections of the ventilation flue is coated with polymer cement slurry (108 glue: cement=6:1);The joints between the ventilation flue and the floor slab shall be roughened in advance, cleaned, and then the formwork shall be erected, and filled with C20 fine stone micro expansion concrete.
(6) The concrete surface at the joint shall be about 3cm lower than the floor.After filling the concrete, store water on the concrete surface for curing.
(7) After cleaning the foot position of the ventilation flue, make two coats of 851 with a thickness of 2mmPolyurethane waterproof coating20cm high;Or a reinforced concrete water retaining base surface of 1:2.5 cement mortar shall be tamped around the foot of the ventilation flue. The water retaining base surface shall be batched and polished before the floor cement sand finishing layer.The reinforcement shall be reserved when tamping fine aggregate concrete for sealing.
(8) Before batching or finishing, a net shall be hung around the ventilation flue.
(9) The joint between the two floors of the ventilation flue shall be coated with polymer cement paste on the joint surface of the upper and lower ventilation flue, and then the exposed part of the joint shall be coatedGalvanized steel wire meshAnd weld the embedded steel plates of the upper and lower pipes with Φ 6 reinforcement.
(10) After the ventilation flue is installed on the roof, anti back flow hoods required by different series of products shall be installed according to the design requirements.[3]
matters needing attention
(1) Before installation, the ventilation flue must be checked to see if the model and floor number are consistent;Check whether the reserved holes of each floor slab are vertically aligned from top to bottom, or they shall be treated to meet the requirements before installation.
(2) The ventilation flue shall be installed before the floor pavement and wall ceiling painting.The installation shall be carried out layer by layer from bottom to top, and attention shall be paid not to drop sundries into the ventilation flue.[3]
Design and Application of Flue Purger
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1) Design background
Tahe OilfieldThe internal structure of the heating furnace at the wellhead and station makes it difficult to purge and clean the flue. Long term use of the heating furnace causes problems such as the decline of the heating furnace system, water dripping from the chimney, and backfire of the burner;It is difficult to clean the flue U-tube by manual cleaning.
The heating furnaces in Tahe Oilfield are all indirectly heated by fire tube type water jacket, and the combustion flue is of U-shaped structure. Therefore, carbon deposits are formed in the flue and furnace channel after the long-term operation of the heating furnace. The first cleaning method of the plant regulations is to open the explosion-proof door or baffle at the end of the flue and the connection between the flue and the flue, and the operator holds a long rod slightly larger than the flue of the heating furnace,The front end is fixed with large cloth or cotton yarn with iron wire, and the operator will go deep into each flue and push and pull the long rod back and forth to clean the carbon deposit.Second, when the manual cleaning can not achieve the effect, the diesel engine will be used to drive the large air compressor to connect the gas pipeline;First, clean it manually in the same way, and then remove the nozzle and burner. Back purge the air compressor gas outlet pipeline from the furnace, and purge the carbon deposits accumulated at the U-tube in the earlier stage.
Because it is difficult to clean the flue, the on-site operation also uses the form of burning and blasting to deal with the flue, furnace flue and chimney at one time, which is to discharge a certain amount of natural gas and ignite it suddenly, resulting in a small range of deflagration, and use the explosion vibration to make the carbon deposit on the pipe wall fall off, so as to achieve the purpose of cleaning.
The purging machine uses the power of the electric air compressor to install a high-pressure four layer steel wire wound rubber pipe with a length of 6 meters and a diameter of 25 mm at its outlet, and an iron scraper with a diameter that can be adjusted at any time is installed at its front end. The motor is installed with an air switch that meets the safety specifications of the oil field. The 100 meter long, 3 * 6+1 rubber sheathed cable is used as the power transmission device,The base is provided with four solid rubber wheel rolling movable supports, and the outside is protected by 2mm steel plate.It is mainly composed of motor andAir compressor, cable and switch device, purging pipe assembly line, flue scraper, support and protective cover.
3) Process principle
(1) Design a pickup truck that can be moved at any timeAir compressor。
(2) Process a set of cylindrical scrapers matching the flue of each type of heating furnace.
(3) Process a set of pipe line connecting device matched with the air compressor and scraper.
(4) Add a set of protection device and cables and switch devices required by the power system to the air compressor.
(5) When working, connect the motor cable of the flue blower to the secondary cabinet or the starting cabinet of the pumping unit on site.
(6) Connect the purging pipeline of the flue machineHigh pressure hoseAccording to the model of the heating furnace, connect the iron pipe with a certain length of thread, and finally connect the high-pressure rubber pipe with a scraper head of 50cm with the same diameter as the flue of the heating furnace.
(7) FirstHeating furnace burnerDismantle, open the explosion-proof door of the heating furnace, and then put the purging pipe into the smoke pipe in the flue. Start the switch, and then scrape back and forth according to the amount of ash in the flue. You can go deep into the other side of the smoke pipe for cleaning until no carbon deposits are discharged, and then continue to clean the next smoke pipe.The purging machine only needs two people to cooperate with the operation, and can be cleaned in a short time and completely without repeated cleaning. A reasonable ash cleaning cycle can be formulated according to the operating conditions of the heating furnace.[4]
