On the roofs of private houses and apartment buildings, businesses, office buildings visible chimney. They end with caps of different shapes, often beautiful, to give additional aesthetic exhaust design. Headroom chimney - functional additional element.
appointment
Dymnikov serve several functions:
- Protect the chimney from being destroyed by the action of rain, snow and wind.
- Protects pipes and boilers from precipitation, which may negatively affect their work.
- Closes the channel from birds, leaves and debris.
- Normalize pressure, serve to enhance traction, protect against reverse thrust effect.
- Protect the roof from sparks that matters for solid fuel boilers.
materials
The material from which the head part is made affects the durability. Distributed samples of steel, copper, and zinc-titanium alloy:
- Steel visors for chimneys cheapest. But they have a short lifespan. After 5 - 10 years, this additional element will need to be changed. When operating the boilers TT-term steel cap service even fewer (3 - 5 years). Galvanized iron even less durable. It burns quickly. Using a stainless steel end walls will extend the life of up to 30 years. This material is resistant to corrosion and high temperatures. But its price is higher.
- Brass caps - as leaders and aesthetics. The high cost of copper products is justified by their longevity (50 years). The only caveat - for their installation will be required as copper fasteners and hardware. With other metals, copper will react, oxidized, leading to deterioration in tip attachment points.
- Zinc-titanium construction also worked well with similarly high price.
Not so long ago appeared on the market additional elements of the roof of the polymers. The relatively low price of these peaks did not pay off. The polymer is not sufficiently heat-resistant, atmosferostoek, besides fragile. Time-tested options for copper, zinc, titanium, and stainless steel are spent for their money.
types of end walls
Chimney caps are varied forms. There are two basic types of end walls: the simple visor (various configurations) and deflector.
Normal headroom, which is a lid covering the top of the chimney, protects against dust and moisture. When properly installed on 15% -20 increases the beneficial effect of the ventilation system. Sometimes it several forms:
- gable;
- hipped;
- gambrel;
- umbrella;
- flat;
- conical cap.
Gabled and hipped - the simplest kinds of caps onto the pipe. Resemble conventional roof of a house. Well with a pipe protection. They are easy to make his own.
In hip hood and 4-way, 2 of which are triangular, 2 - trapezoidal. Most installed on square and rectangular tubes. Provides good protection for the chimney, snow facilitates convergence.
Flat headroom to mount the easiest, but it is the least effective. Snow layer on its surface may deform the product, lead to a rapid failure of the attachment locations. Caps umbrella and differ only in the cone angle of inclination of the ramp. At less delayed tapered snow, but its function of protection and increased thrust are both operate. To make the hands of such a cap on the chimney of galvanized sheet is easy.
Attention! For the functioning of headroom you need to follow a few rules of installation. Main: distance between the upper edge and the lower edge of the chimney hood should be 10 cm. Minimal distance impede the passage of exhaust gases and smoke will contribute more blowing boiler. Distance of 10 cm the test of time, it is not recommended to change.
Pros and cons of the spark arrestor
Sometimes between the chimney and the cap is installed spark arrester. Most often, this function is performed by a metal mesh. This is true for boilers using solid fuel. In addition to protecting the roof and the environment from possible sparks mesh additionally protects the chimney from the garbage, does not allow the birds to sit on its edge.
But the spark arrestor mesh, there are downsides. Together with the smoke exits steam, as one element of the combustion products. With the heat, winter it condenses on the cold metal tip and the grid, immediately turning into ice. As a result of glaciation spark arrester prevents the further exit of smoke. Creates a reverse thrust. Moreover, smoke and gases enter the premises and can lead to poisoning. To avoid this, the grid cells should be large. But sometimes this is not enough. For boilers with high efficiency spark arrestor installation should be completely excluded.
types of baffles
Worse simple headroom operate at air flows upwards. Shot cap, they repel each other and are moved towards the pipe rising from the mainstream smoke. Increases the pressure at the top of the chimney, topples traction. More efficient in this case are deflectors.
This design with a diffuser, designed to catch the wind, scatter it flows and output. Thus, vacuum is created within the baffle, which ensures that the hot air flows upward from chimney flock. Some stabilization of the pressure at the top of the chimney give the usual headroom. But if they increase cravings by 15 - 20% compared with the open pipe, the diffuser to increase this percentage up to 30 - 40%.
There are several types of deflectors:
- TsAGI.
- Wolpert - Grigorovich.
- H-shaped deflector.
- Rotary: ball-shaped weather vane.
Central Aero-Hydrodynamic Institute has developed a universal model of the deflector. It consists of a fixed on the chimney of the ring and connected to it with an umbrella cylindrically shaped screen. Falling within the bottom structure of the wind flows dispersed, striking the cover hood and the cylinder wall, and then out through the gaps between them. The chimney is protected from rain and strong wind direction.
It has disadvantages:
- In calm weather traction deteriorates.
- When severe frosts small distance between the umbrella and the cylindrical screen may freeze, preventing the passage of smoke.
Deflector Wolpert-Grigorovich looks like bunk "skirt". Its lower part - a cylinder or a truncated cone, the top - cone 2, forward and reverse. The curved surface of the diffuser is effective at low winds.
H-shaped deflector outlines like the letter N. The flue channel is connected with a transverse pipe of the same diameter at both ends of two pipes which are parallel chimney. Wind currents may enter only in the side channels. Most of them immediately goes up, without disturbing the waste products of combustion. The remaining part, getting into the transverse channel, is not able to create a serious pressure and output together with the smoke. Excluded smoke. The visor in such a construction is not required since the lateral mouth of the protected pipe.
Round turbine in calm weather goes on, without impeding the exit of smoke from its vents. Under the action of the wind as it rotates, creating a reduced pressure inside and increasing thrust. Baffles having aerodynamic properties to rotate around its axis under the action of air flows. Protects wind vane or vane flue mouth by wind currents, which are forced to bypass it, creating a vacuum.
Rotating vents are usually installed where using gas heating equipment. they are not recommended for boilers mounted on TT high temperature waste smoke.
From all this we can conclude:
- If the head part is mounted on the chimney of the boiler to TT, it is sufficient to be a simple cap made of copper, zinc, titanium or stainless steel. The grid is better not to install in areas with a very frosty winter to avoid freezing.
- For heating boilers with gas vents are permitted to improve traction. In areas with frequent winds, located on high ground, their susceptibility to air flow will be most welcome.
- End walls on the brick chimney pipe with side ducts, particularly of the equipment with high efficiency, it is desirable to make gable or hip without closing the exhaust gas passage.
installation technology
There are rules governing the height of the chimney, taking into account the distance from the ridge. Wrong calculation of height will reduce traction and even to reverse the movement, that is, to a smoky environment. If the path of air flow will be ridged roof slope, it is such an effect and turn.
Technology regulates:
- On a flat roof chimney height should be at least 0.5 m.
- In the gable, hipped roofs and hipped chimney spaced from the ridge to a distance of 1.5 m, it should be higher at 0.5m.
- If the pipe to the ridge of 1.5 - 3 m, the chimney mouth may be flush with the ridge horizontally.
- If the chimney duct is spaced from the ridge of more than 3 m, then the angle between them should not be greater than 10 degrees.
If desired, the cap or deflector for the flue pipe can be made with your own hands, if there is at least minimal experience with metal, metal scissors, stainless steel sheet, measuring instruments (ruler, roulette). First the layout and drawing the future of the deflector. Blanks cut from cardboard or stiff paper, then transferred to the stainless steel sheet.
Attention! When calculating the dimensions should be remembered that the upper part of the tip should be greater than 10 cm tube, the distance between the pipe and the cover - 10 cm.
Making the cap in a conical tube for chimney
Procedure:
- First, the pipe length is measured circumferentially, is deposited on the cardboard. To make it easy to put the base on the flue, added 30 - 40 mm. The strip of this length will justify-clamp.
- The radius of the tube is measured, a circle is drawn with an allowance of 15 mm for protruding edges. Sector is drawn from the center of the arc of about 120 mm. This wedge cut.
- The edges of all the individual parts fit together, fastened klopochnym connection.
- Feet mold made of narrow strips of steel, slozhonnyh 2 - 3 for the strength of the layer.
- The supports are attached to the umbrella and the yoke.
- Junctions are primed, the finished product is painted anti-corrosion paint.
Making deflector Grigorovich - Wolpert
It is made by analogy with the conical cap:
- Made two umbrellas, connected to each other edges. In the upper cone makes an incision along the edges for attachment to him stands. The diameter of the cones twice the diameter of the chimney pipe.
- The deflector has a width and a height of 1.5 to 1.6 diameter of the flue. The outer cylinder is made similar to the diffuser cylinder. Turning preform dock their rivets.
- Tabs connected umbrella with a diffuser, the entire structure is inserted into the outer cylinder.
