Most private houses and summer cottages are equipped with autonomous heating systems that run on gas, solid and liquid fuels. The efficiency of heating the coolant largely depends on the quality of the output of combustion products and the volume of fresh air entering the furnace. When the boiler is turned off, it becomes necessary to close the outlet channel so that warm air from the room is not sucked into it and foreign objects do not get into the furnace. To accomplish these tasks, a chimney damper is used - a simple but effective device invented many centuries ago almost simultaneously with the appearance of the first stoves. The part can be supplied with the boiler or purchased separately. If you have ordinary household tools and the ability to handle them, you can make a damper for a chimney oven with your own hands. To do this, you should familiarize yourself with the purpose, principle of operation and manufacturing technology of this device.
Definition of the concept of a damper for a chimney
A chimney damper is a device with the help of which the channel leading from the firebox for the removal of combustion products is completely or partially blocked. The product can be used in heating and ventilation systems. The chimney valve works in a similar way to a water ball valve embedded in a water supply system.
By performing various manipulations with the gate, the size of the pipe section is adjusted. This allows you to increase the draft to quickly warm up the room or reduce it in order to save fuel and maintain the combustion process at the desired level. Chimney valves are made of rigid metal that can withstand temperature changes, mechanical stress and corrosion.
Device and principle of operation
Because the chimney valve is exposed to high temperatures, moisture and chemicals, the part is made of cast iron or stainless steel, high performance materials.
Structurally, the chimney damper is a shut-off equipment consisting of a body and an adjustable element having a different configuration and adjustment technology. Adjustment of the intensity of movement of furnace gases is carried out by shifting the valve horizontally or around its axis. The valve is made according to the configuration of the pipe and can be installed in channels of rectangular, square and circular cross-section.
The principle of operation consists in adjusting the draft by expanding or narrowing the branch duct. When firing up and to reach the maximum temperature in the furnace, the valve completely releases the pipe. When the required temperature is reached and to switch the oven to a long-term burning mode, the damper closes the chimney until the optimum ratio of incoming air and exhaust of furnace gases is achieved. In the periods between using the boiler, the device is in a closed state.
The range of application of the dampers is practically unlimited. They are mounted in potbelly stoves, heating boilers, sauna stoves. The installation of dampers allows you to prevent the blowing of combustion products into the room when a reverse draft is formed.
Types of chimney dampers
Different types of dampers can be used to regulate the flow of combustion products. The choice is made based on the configuration of the channel and the material of its manufacture.
The following design solutions are possible:
- Retractable installation. The product is a round or rectangular plate moving along guides inside the pipe. Due to the presence of openings inside the channels, the frame is kept in the nest, keeping itself as tightly in the pipe as possible. Adjustment is made by pushing the plate back and forth to achieve the desired result. Most often, retractable devices are used in square brick pipes. In circular ducts, they also perform their functions effectively.
- Throttle valve. The classic rotary damper for the chimney consists of a steel or cast iron plate rotating around its axis. The rod is inserted into the holes in the pipe walls and is not removable. The gas flow is adjusted by rotating the frame to a certain angle, after which the product is fixed. Various models are equipped with manual or electric drive, including remote control.
The air damper can be an independent or auxiliary element of the chimney. Its task is to close the chimney against strong gusts of wind even after the end of the firebox. The thrust is adjusted by the force of the spring that connects the pipe to the damper. It is not difficult to make such a gate for a chimney with your own hands, but it will bring a lot of benefits.
Advantages and disadvantages
Like any engineering structure, stove dampers have their pros and cons.
The advantages include:
- the ability to adjust traction;
- saving fuel by reducing the volume of air supply to the furnace;
- preservation of the heat of the furnace after the chimney is closed;
- blocking wind blowing.
Disadvantages of designs:
- throttle-type products are unreliable, may wedge and not close from the adhesion of soot;
- rotary devices make it difficult, and sometimes make it impossible to clean the channels;
- correct adjustment requires experience and skill.
With proper installation and proper handling, the dampers make it possible to make the boiler furnace more convenient, economical and safe.
Methods for installing a damper for a chimney
There are the following rules and methods for installing a gate in a chimney:
- in brickwork - at a height of 60-80 cm from its base;
- in a steel pipe - joint to joint (in sockets) in a section that is not insulated;
- height from the outlet of the metal chimney - at least 150 cm in order to prevent thermal deformation;
- the flap should move in the grooves and rotate on the rod freely, without getting stuck;
- making a hole in the valve for the release of carbon monoxide gases with early blocking of the channel.
In all cases, marks must be made on the damper handle, with the help of which its position in the pipe is monitored.
Making a damper with your own hands
The initial stage in the manufacture of a valve on a chimney pipe with your own hands is to take measurements and draw up a drawing. On the basis of the project, the calculation of materials and equipment is made.
For work you will need:
- drill, grinder, welding machine;
- a hammer;
- vice;
- pliers;
- core;
- tape measure, compasses, marker;
- stainless steel sheet 2.5-3 mm;
- rod for the frame.
Particular attention should be paid to the size of the product. The bar holes must match exactly horizontally. You should take an allowance of 1-2 mm, since the steel expands when heated. The frame should not touch the inner edges of the guides, and the throttle valve should not touch the pipe walls. Before final fixing, check the product in all operating modes.
