In the rural areas of China, there are many types of wood-saving stoves all over the country according to the local living habits, traditional culture and economic conditions. Firewood-saving stoves can be divided into the following categories according to different criteria:
According to the way of construction, they can be divided into handmade masonry stoves and commoditized stoves; commoditized ones generally come with hot water, water tanks, and smoke pipes.
By the way of ventilation to help combustion, can be divided into self-pulled air stove and forced ventilation stove (with wind box or fan).
According to the different relative positions of the chimney and the stove door, can be divided into the front of the wind stove (i.e., the chimney and the stove door on the same side) (and the back of the wind stove that is, the chimney and the stove door on the opposite side of the chimney and the stove door).
By the number of pots, it is divided into single, double and multi-pot stoves.
By fuel, divided into hard wood stove and soft wood stove.
Second, the technical points of firewood and coal stove
Rural firewood and coal stove should follow the following design principles. First, it has excellent cooking function, the second is discharged into the indoor pollutants at least, the third is to be able to adapt to a variety of tender and save wood and coal, the fourth is the structure to adapt to the use of habit, beautiful, hygiene and safety, the fifth is the northern cold areas should be waste heat for indoor space heating, the sixth is the investment is small and durable structure.
1. Technical route (process)
In order to improve the thermal efficiency of wood stove, minimize heat loss, in order to achieve the purpose of saving wood, save time, it is necessary to figure out the fuel in the wood stove combustion process of heat generated by a variety of specific destination, and targeted transformation. According to the structure and characteristics of the wood stove, the heat loss of the wood stove is mainly exhaust heat loss, chemical and mechanical incomplete combustion heat loss, ash take away the heat loss as well as the stove body, the pot body heat storage and so on.
From the structural aspect of the stove type, the old-style wood stove structure is unreasonable, incomplete combustion, poor thermal insulation, heat loss, so the thermal efficiency is low. Its main shortcomings are: "two big" (stove door is big, stove big), "two no" (no chimney, no grate), "a high" (hanging fire high, generally around 30 centimeters). Compared with the old-fashioned firewood stove, the provincial firewood stove has the advantages of "two small" (smaller door and chamber), "two have" (grate and chimney), and "one low" (lower fire) (Figure 6-1), and its structure is comparable to that of the old-fashioned firewood stove (Figure 6-1). -1), the structure is more reasonable, there is a complete ventilation system, can get more adequate combustion. Due to the setting of the heat preservation layer, increase the fire stopping ring, prolong the high temperature smoke gas flow in the stove chamber of the return journey and time, so that the heat loss is reduced, the thermal efficiency is improved, both save firewood and masonry to save firewood stove methods and drawings - red leaf - Ri Zhi Zhai save time, and safety and hygiene, easy to use. According to the tests and surveys around the country, save firewood stove is generally more than the old-fashioned firewood stove to save firewood l / 3 ~ l / 2, save time 1/4-1 / 3.
From the thermodynamic principle, save firewood stove basically reached the energy saving of the three conditions: First, the fuel can be fully combusted, so that the chemical energy in the fuel is more completely converted into heat energy. Secondly, the heat transfer and insulation effect is good, so that the effective utilization of the calorific value is larger, the heat dissipation of the calorific value is smaller. Third, the waste heat can be better utilized to minimize the exhaust waste heat and other heat losses. This is the important reason why the wood-saving stove can save energy.
2. The main technical aspects and points
(1) the characteristics of the components and equipment. The basic structure of wood-saving stoves includes the stove body chamber, air intake ducts, grates, chimneys and so on.
(2) The main performance parameters of the technology. According to the living habits and cooking methods in rural areas around China, the wood-saving stove should generally have the following performance characteristics:
First, the ignition is easy to start the fire quickly. In order to increase the temperature of water or food, such as boiling water or heating during food processing, it is required to ignite easily, start the fire quickly, save time and labor.
Second, the continuous heating efficiency and adjustable temperature. Cooking process, the need for a certain temperature, continuous heating for a period of time, and adjustable temperature. For example, steaming, cooking, frying food, the three different only lies in the maintenance of the temperature is not the same, with the deep-fried need to be higher than the temperature of the steaming.
Third, safety and health and good insulation. Direct use of radiant heat and conduction heat processing food, such as baking, cooking, frying food, the need for wood stove stove mouth does not smoke, stove insulation, waste heat can be utilized.
Fourth, high thermal efficiency. General firewood stove thermal efficiency should be more than 25%, while the new firewood stove requires thermal efficiency to be higher than 30%, and can adapt to the local basic living energy requirements.
Three, the structure of wood-saving and coal-saving stove
Methods and drawings of masonry wood-saving stove - Red Leaf - Nichijisai
Wood-saving stove construction diagram
①Chimney position Chimney is preferably set in the ridge of the house, and above the ridge of the house more than 0.5 meters.
② increase the grate in order to make the burning of paddle, coal, the air required to supply the appropriate way to reduce the air into the door of the stove, increase the air through the layer of firewood, improve the frustration of the stove, the general position of the grate as shown in Figure 8-1.
Methods and drawings for building wood-saving stoves - Red Leaf - Nichijisai
In order to increase the area of air intake, easier removal of ash and to prevent the untenderness of all the firewood and coal fall into the ash chamber, the general use of the structure of the grate as shown in Figure 8-2 form. And appropriately narrow the stove door, so as to avoid too much cold air into the stove.
Four, the design of the combustion chamber
One is to determine the shape. The shape of the combustion chamber is mainly columnar, pot-bottom shape, crescent-shaped and arc. Column structure is the simplest, while the arc of the best combustion performance, according to local habits of choice to determine.
The second is to determine the volume of the combustion chamber. The diameter of the upper mouth is generally taken on the diameter of the pot 60% -70%, the height of the combustion chamber should be based on the local user requirements for the heat load and the use of customary correct design. Height is too small, each time to add less firewood, inconvenience, but also because the combustion chamber volume is too small to make the firewood burning incomplete; height is too large, the fire dispersion, the stove chamber temperature is too low, affecting the combustion and heat transfer.
Three is to increase the stop fire. Stopping the fire has to make the resistance to smoke flow and chimney pumping force to match, to avoid volatile components in the case of incomplete combustion is pumped away, to guide the smoke back around the bottom of the pot around a long time, so that the role of combustion and heat transfer time is sufficient. Stop the fire that is to control the gap formed between the bottom of the pot and the upper edge of the combustion chamber, prompting more flue gas from the stove door at the larger gap into the return flue, and then relocated back to the bottom of the pot into the smoke outlet method.
In short, the energy-saving stoves, fuel-efficient stove design to have both good burning, heating strength is sufficient, fuel-efficient and easy to use and other characteristics.
Fifth, the promotion of wood-saving stove matters needing attention
Promotion of wood-saving stove most need to pay attention to is how to correctly carry out the external construction of wood-saving stove:
The first step is to build the stove body. The stove body mainly plays the role of heat preservation and bear the weight of the pot. Stove body diameter size can be determined in this way: that is, with the internal diameter of the combustion chamber plus the bilateral thickness of the combustion chamber structure, plus the thickness of the thermal insulation layer, the sum of the three is the internal diameter of the stove body size. The exterior of the stove body should be done neatly, face flat, in order to facilitate painting.
The second step is to build the stove door. The role of the stove door is to add fuel and observation of combustion, its position should be lower than the smoke outlet 3 to 4 centimeters, if higher than the smoke outlet, there will be prairie smoke phenomenon. General rural stove door 12 centimeters high, 14 centimeters wide, burning grass stove door can be larger, burning coal stove door can be smaller. In order to prevent heat loss from the stove door, the stove door should be installed on the movable baffle with observation holes.
The third step is to build the stove. Usually protrudes from the stove body 4-8 cm, made a kind of drip edge, not only convenient to use, but also beautify the stove shape. When building the stovetop, also pay attention to the inner mouth left 3-4 centimeters, in order to do the edge of the pot.
The fourth step is to wipe the edge of the pot. The edge of the pot is close to and support the structure of the iron pot, often made of hard clay or mixed clay. Generally, the thickness of the edge of the pot is 25-30 centimeters, wipe the edge of the pot is 20-25 centimeters, small pots, especially small pots 15-20 centimeters. Wipe the pot edge, should be wiped while using the pot test, and strive to wipe tight, do not run out of gas; pot edge beyond the height of the stove surface should be controlled within 3 centimeters, in order to increase the heating area of the pot.
The fifth step is to build a chimney. The chimney has a certain amount of pumping power, can ensure that the combustion chamber into the sufficient air, and will be combustion process of exhaust gas to the atmosphere. The height of the chimney of household stoves is about 3 meters, and the inner diameter of the outlet is 12 to 18 centimeters. A gate should be provided at an appropriate position in the chimney to control the adjustment of the chimney's draw, and ash holes should be left at the base of the chimney. If prefabricated chimneys are used, the internal diameter should not be less than 16 cm. In general, the chimney should be 0.5 meters above the ridge.
The sixth step is painting. Painting should be in the stove test after passing, general stove surface, smoke outlet and other parts of the best use of l:3 cement mortar painting. Stove surface such as tile, generally should be in the stove of various performance to meet the technical requirements and stove body after drying.