1。 Structure and Features The high-efficiency prefabricated overhead kang structure consists of lower kang column, kang bottom plate, kang wall, inner kang column, kang tip smoke barrier, kang inner cold wall insulation layer, kang tip smoke insertion plate, kang panel, kang surface mud, kang eaves and kang wall bricks. Through scientific design, the high-efficiency prefabricated overhead kang furnace has the heating performance of large heat utilization area and fast heat transfer. It has the uniform temperature performance of suitable heat on the kang, under the kang, at the kang head and at the kang tip; And has heat preservation performance of prolonging heat dissipation time. These three performance characteristics are the fundamental reasons for the high efficiency and energy saving of overhead kang. 2 Material selection The floor-standing kang is made of bricks and adobe. Although the thermal performance is good, the design of kang body is not satisfactory because of its small area, low strength and short service life, and it is difficult to standardize and finalize the design. Therefore, it is necessary to find an ideal kang body material. According to the requirements and experience of human body, the temperature of the kang surface should be 25 30 degrees Celsius, and the temperature after each fire should be 8 65438 05 degrees Celsius, which requires the kang body material to have the following properties: certain mechanical strength, long service life, firmness and durability; The materials are easily available, the price is cheap, and users can afford it; It has certain heat storage performance and heat transfer performance. The materials of high-efficiency prefabricated overhead kang are selected according to the availability of materials and the thermal performance index of materials. See the table below.
As can be seen from the table, slate is the most ideal material for sports, followed by concrete slab, and its mechanical strength is also better than brick and adobe. Slate is good, but limited by the source of br/ material, it is not easy to popularize in a large area. Therefore, in addition to slate in resource-rich areas, concrete slabs can also be used for efficient prefabrication and assembly of overhead kang, as well as the determination of slab size and the requirements of steel bars. For example, the optimal size of each slab and the number of slabs used must be determined before prefabrication and beating. Its measurement method: measure in the house with kang. Take the actual size of the user's kang length MINUS 50 mm divided by 3, which is the length of a kang board; The width of the kang board is 600 mm and the thickness is 50 mm, so three kang boards of this specification are needed. Multiplying the length of the kang board by the width of 500mm and the thickness of 50mm requires three kang boards. In other words, the length of the kang is 50 mm, and then divided by 3 mm times 600 mm times 50 mm. The total number of such kang boards is 15. (The length of the kang is 50 mm) Divide it by 3 and multiply it by 500 mm and then multiply it by 50 mm * * *. When in use, 9 kang bottom plates are 600 mm wide, 6 kang panels are 600 mm wide and 3 kang panels are 500 mm wide. The total number of upper and lower boards of the whole overhead kang is 18. 6.5 mm is better for reinforcement. Take a 1000 mm *600 mm *50 mm (length and width) kang board as an example. The arrangement of steel bars is shown in the following figure.
4. Standards and requirements of materials used for cement concrete kang boards: cement requires that the production dates of 325# and 425# should be within 3 months; Medium and coarse sand to be washed should be free of weeds and soilless when used; Stones need gravel or pebbles with a diameter of15 30 mm. The curing period before use must be kept for more than 28 days. 5. The proportion of cement, sand and stone in the cement concrete kang board requires that the kang board be hollowed out with cement concrete: if the kang board is hollowed out with 325# cement, the cement, sand and stone can be synthesized according to 1:2:2; If 425# cement is used to hit the kang board, cement, sand and stone can be synthesized according to 1:2:3. 6. Material preparation sequence for laying kang Before laying high-efficiency prefabricated overhead kang, the specific preparation sequence is as follows: (1) Laying cement concrete kang board more than 25 days in advance or preparing shaped slate and red brick kang board in advance. (2) Remove Laokang 1 0 weeks in advance. At the same time, it is also required to lay a cement concrete floor under the kang, and then build an overhead kang after the kang is lifted and the cement is completely solidified. (3) Prepare other materials: 1 m3 medium sand; 0.6 cubic meters of clay; 200 bricks; Two bags of 425# cement; 0.2 cubic meters of fine slag; Cigarette board; Kang wall brick 50 pieces 70 pieces 152 model.
Tuesday, 4 March 2008
Go and have a look. Very detailed.
The second construction technology of hanging kang: the key points of building hanging kang.
Treatment of the ground under the hanging kang
The bottom of the hanging kang is supported by several columns. These pillars in contact with the ground are under great pressure. If the ground is not properly handled and sinks, cracks will appear in the whole kang body or in some parts, which will affect the heat of the kang and even cause soot poisoning. Therefore, the quality of foundation treatment under the hanging kang is the key link of the effective life of the kang. Whether building a new house or an overhead kang in an old house, leave the smoke outlet of the stove and the smoke inlet of the chimney well, and then build the kang when it is hygienic. The key is to deal with the foundation under the fulcrum to avoid sinking.
2. Lofting and masonry method of hanging kang ground column
(1) pay-off method. When laying hanging kang, the setting-out position should be determined according to the size of the hanging kang plate prepared in advance. Operation sequence: measure the length and width of each kang board with a ruler, and then draw the position grid of each kang board with strokes on the ground below the hanging kang, so that the positions of the nine kang boards are clear and accurate, and each pillar is required to be placed in the center of the intersection of the kang boards. (2) Masonry requirements. When laying kang floor columns, the gap between the floor and the floor should be aligned with the center line of the column, and the middle column plane 1/4 is just at the corner of the floor. Stay wires should be used when laying. The ash port on the kang tip and kang can be slightly larger, and the ash port under the kang can be slightly smaller, so that the kang tip is slightly higher than the kang, and the kang is slightly higher than the kang, with a height difference of 20-30 mm. The bottom column is120mm *120mm * (350 370mm (length * width * height).
3 Laying and sealing treatment of hanging kang board When laying hanging kang floor, you should first select a cement kang board with straight edges and complete corners and put it on the outside. Hold it steady when placing it, starting from the inner corner, and then put it down steadily. After placing the kang and the kang, measure whether the width of the kang and the kang are consistent. Straighten the bottom corner of the cement kang board at the outer mouth of the kang wall with iron wire to lay a good foundation for building the kang wall and plastering. The whole kang floor will not be unstable and pried after installation. After the bottom plate of the overhead kang is placed, the gap in the bottom plate shall be leveled with 1:2 cement mortar. Then the mixed grass, sand and mud are synthesized according to the ratio of 5: 1, and the upper layer of the bottom plate is smoothed to a thickness of10 mm; Then put the screened dry fine slag on it for leveling and tamping to achieve the effects of compactness, smoothness and heat preservation.
4 masonry requirements of kang wall
The masonry type of hanging kang wall is divided into flat type, and the upper and lower outlets are indented along the middle. The kang wall must be laid by pulling wires, and can be laid by 1:2 cement mortar and vertical bricks. The building height of the kang wall is 260mm at the kang head and 240mm at the kang head. When laying, soak the red brick in advance to determine the type and height; The size of ceramic tiles should be selected in advance to meet the requirements of sports.
Layout and requirements of kang column brick
The number of kang column bricks depends on the size of kang board. Before placing column bricks in the kang, a layer of dry and fine slag ash can also be laid on the upper floor of the kang. Screen it flat with a sieve, and then put the brick column on the kang surface. The column brick in the middle of the kang is slightly lower than the column bricks on the upper and lower sides of the kang1015 mm. At the same time, the inner wall of kang is built on the inner wall of cold wall or other walls, which is not only the pillar of kang panel, but also the insulation wall of cold wall. The height of column brick in kang is kang head120mm x120mm x180mm, and kang head 160mm (length x width x height). Kang's column brick layout is shown in the following figure.
Heat preservation treatment of Kang 6 partial cold wall
The external wall in contact with the hanging kang is a cold wall, and this part of the wall should be insulated to avoid the burning of the stove or the heat of the kang due to frosting, ice hanging, water supply and ventilation. When laying this part of the fence in the kang, bricks should be erected, the mortar mouth should be placed horizontally, and a 50mm wide gap should be left with the inner wall of the cold wall. Heat preservation refractory materials such as perlite or dry fine slag ash should be put in, tamped with wooden sticks, and then smoothed with fine grass and sand.
7 the size of the smoke barrier behind the kang
A rear smoke barrier is added at the top of the hanging kang, and the structure of slow-flow herringbone smoke separation wall at the top of the kang is adopted. This smoke separation treatment can prevent the smoke at the kang tip from directly entering the chimney, so that the smoke at the kang tip, especially the smoke at the entrance of the chimney, changes from rapid flow to slow flow, prolongs the heat dissipation time of the smoke at the kang tip, reduces the smoke exhaust temperature, and eliminates the upper and lower dead corners of the kang tip. The herringbone smoke screen on the top of the overhead kang can be made of precast cement or red brick. The herringbone smoke barrier is 420 mm X 160 mm X50 mm, and its internal angle is about 150 degrees. According to the suction of the chimney, the distance between the two ends of the smoke screen and the kang tip wall can be determined to be 270 mm× 340 mm. The contact part between the top surface of the smoke barrier and the kang surface should be sealed with mortar, and no smoke is allowed to escape.
8 Installation requirements of smoke baffle at smoke outlet of kang head
In order to keep warm and reduce heat loss, a smoke screen must be installed at the smoke outlet at the tip of the kang. Installation and operation method of tobacco board: firstly, put the selected tobacco board with flexible switch at the smoke outlet of kang, and level the bottom with water, silt and ash. When the inner wall of the kang is to be built on both sides, the height of the top of the smoke plate should not be higher than the height of the two sides of the wall, but slightly lower than 5 mm. The pull rod of the cigarette board can be led out from the kang wall, and the contact points at both ends must be horizontal. The outer side of the kang wall at the kang tip can be made into a ring shape or a T shape, which is convenient for opening and pushing. After installation, don't walk around at will to avoid loosening and affecting the cement solidification effect.
The third construction technology of hanging kang: hanging kang construction method
Before placing the hanging kang, the kang panel should be sealed to solve the problem that the lower part and two sides of the kang panel are not tight and avoid smoke leakage. The operation method is as follows: when placing the kang board, the screened and mixed grass sand mud is used, and a layer of fine grass sand mud with millimeter thickness is coated on the top surface of the inner wall of the kang around, so that the lower part of the kang board contacting with the wall is covered with a layer of mud, and then the grass sand mud extruded from the kang board is connected with the kang surface mud and smoothed to achieve the effect of tilting and tightening around the kang board.
2 Proportion and thickness requirements of Kang surface mud
Proportion of hanging kang surface mud: the first mud is made of coarse medium sand and clay according to the ratio of 5: 1; For the second time, medium fine sand and clay were used to synthesize mud according to the ratio of 4: 1. Hang kang kang surface mud requires two times, the first time is sediment, and leveling and compaction are required when plastering kang surface mud. The thickness of the kang is 55 mm, and the thickness of the kang tip is 35 mm. When the mud is 80% dry for the second time, it shall be leveled, added with appropriate amount of white plaster, with a thickness of 5 mm, and it shall be smooth and crack-free after the mud is plastered for the second time. Practice and experiments show that the material used for hanging the kang surface mud is sand mud, the thickness of the kang head is 60 mm, the thickness of the kang tip is 40 mm, and the average thickness is 50 mm, which has the best effect, is beneficial to the heat storage and insulation of the kang body, and can better solve the problem of hanging the kang in the middle of the night and cooling quickly.
3 Kangti tile
To hang kang kang wall with ceramic tiles, we should first find the bottom and cement mortar pits, and find the edges and corners in advance where there are edges and corners. The patterns on the surface of ceramic tiles should be cut and set in advance. Tiles should be soaked in water first, and the soaking time depends on the degree of dryness and wetness of cement-soil pits. Then paste mortar on the back of the ceramic tile and stick it on the kang wall, and tap it gently by hand until it is solid or reaches the required plane. Pay attention to the alignment gap, find a good pattern and strive for a flat surface. Pay attention to the fact that after the tiles on the kang wall are set, the fire cannot be burned for 7 days during the curing period.
The fourth construction technology of hanging kang: adjustment of thermal performance of hanging kang
1. Technical measures to improve the utilization rate of heat energy in the kang 1 The bottom of the kang is overhead, and the bottom is cancelled to increase the heat dissipation area. The floor-standing kang only radiates heat from the kang surface, and the improvement of room temperature mainly depends on indoor floor heating and heating stove. However, the bottom of the hanging kang is overhead, which cancels the pad soil of the kang hole, so that the heat dissipation of the kang body is changed from the original side to the upper and lower sides, and the heat lost by the heat conduction of the original floor-standing kang hole pad soil is also dissipated indoors, which improves the room temperature and the thermal efficiency of the kang. According to the actual measurement, hanging kang can increase the room temperature by 4-5 degrees Celsius compared with floor-standing kang without increasing any auxiliary heating facilities and fuel consumption.
2. Increase the heat gained by the kang body. The heat obtained is determined by the length of heat exchange time between flue gas and kang body, the size of heat exchange area, the residence time of flue gas in kang, the flow rate of flue gas and other factors. The measured results show that the high-temperature flue gas entering the kang body at high speed through the throat of the trumpet-shaped flue gas inlet can quickly spread throughout the kang body and exchange heat with the kang body, thus ensuring sufficient heat exchange time and uniformly heating the kang body. Because the hanging kang cancels the front smoke distribution and small kang holes, it reduces the support points, increases the contact between the smoke and the kang body panel, and enhances the heat exchange between the smoke and the kang body.
3. Reasonably adjust the intake and exhaust temperature. The temperature of flue gas entering the kang directly affects the temperature of the kang, which in turn directly affects the comprehensive thermal efficiency of the kang. In the past, because of the pursuit of thermal efficiency of the cooker, it was simply thought that the greater the fire resistance of the cooker, the better. Although the thermal efficiency of the furnace has improved, the furnace has trapped too much heat, so the kang is often not hot, and it is cold in winter, which leads to the situation of changing the past and changing it again. Hanging the kang requires reasonable collocation of the kang stove, appropriate reduction of the fire resistance of the stove, ensuring that the smoke temperature entering the kang is 400 500 degrees Celsius, and the smoke temperature at the tip of the kang is controlled at 50 80 degrees Celsius, so that the kang body can get enough heat.
Secondly, the technical measures to improve the average temperature performance of kang surface are one of the sensitive indexes to measure the thermal performance of kang. Due to the limitation of the hole size and blocking method, the floor-standing fire kang is easy to form the defects of hot kang head, cold kang head, middle of hot kang, cold kang head, cold kang bottom or one hot and one cold. Hanging kang can solve this problem ideally, and can achieve the effect of full and uniform heat of kang.
1 The artificial resistance of the kang body in a local kang hole was cancelled, and the uneven temperature between kang holes was eliminated.
2. Because the smoke vortex formed by the front smoke separation chamber and various barriers is eliminated, only the rear smoke separation wall is arranged in front of the kang head and the smoke outlet, which ensures that the smoke fills the whole kang body and makes the temperature on the kang surface more uniform.
3. Adjust the temperature of the kang surface through the thickness of plastering material. When the kang is exposed to high temperature smoke for the first time, the temperature of the kang is higher than other parts. In order to improve this situation, two measures have been taken: first, when building the bottom plate of the kang, the tip of the hanging kang is slightly higher than the kang head by 20mm；; When the kang panel is erected, the kang head is slightly higher than the kang head by 20 mm, so that an isosceles trapezoid space with a large kang head is formed from the kang head to the kang head. Because the smoke quantity decreases with the gradual decrease of temperature, there will be no bad combustion phenomenon. Second, when plastering the kang surface, the plastering thickness of the kang head is 60 mm, the plastering thickness of the kang tip is 40 mm, and the average plastering thickness is 50 mm, which ensures the uniform temperature of the kang surface.
The third is the technical measures to improve the thermal insulation performance of kang body. The kang should not only have certain temperature rising performance and temperature equalization performance, but also have certain heat preservation performance. These measures are as follows.
1 There is a cavity inside the hanging kang, and the oven door, throat, smoke outlet and chimney form a smooth flue. If no technical measures are taken, the heat gained by the kang after the ceasefire will be discharged from the channel in the form of convection heat exchange. Therefore, the requirements for hanging kang are as follows: first, smoke screens should be installed at smoke outlets; The second is to install an iron oven door at the oven door, and close the smoke plate and the iron oven door after the ceasefire, so that the whole kang body forms a closed thermal system.
2 Heat preservation and heat storage performance of the kang body The heat capacity is adjusted by plastering the materials on the kang surface. The main material of kang body is generally cement concrete slab or special-shaped slate, and its heat capacity is fixed. If sand mud is used as plastering material, according to theoretical calculation and practical experience, it is proved that the average thickness of plastering surface is mm, and if it is too thin, the temperature of kang will increase quickly and the temperature will decrease quickly.