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Ventilation and air conditioning duct production and installation points
Ventilation and air conditioning duct production and installation points
1. Unable to connect: Because the air duct cannot be connected, it has many advantages such as tight connection joints, good quality of joints, light weight of joints, material saving, simple construction process, saving man-hours, easy to achieve full mechanization, automatic construction, low construction cost and many other advantages, so it has been widely promoted. application. At present, there are dozens of unconnected forms of air ducts, and new forms are still emerging, but according to their structural principles, they can be divided into five types: socket, insert, bite, iron flange and hybrid connection. Unable to connect is mainly used for ducts with small side length, there are C-shaped insert connection and S-shaped insert connection. For the air ducts with smaller specifications, the air ducts whose large side length is less than 450mm are connected by C-shaped inserts, and the air ducts whose large side length is greater than 450mm and less than 1000mm are connected by vertical S-shaped inserts. The ends of the inserts are riveted with the air duct, and then sealant is applied to the gap to ensure the tightness of the air duct. The basic measures to improve the construction quality of the wind passenger can not be connected are as follows:
1. According to the requirements of the specification, strictly control the use range of each flangeless joint, such as "S" and "C" shaped inserts, the long side of the rectangular air duct is not more than 630mm, and the vertical bite is no more than 100mm. The vertical bite is 90 The width of the sticking angle should be consistent with the height of the vertical bite, and the 90 degree should be accurate. When the interface joint is connected to the flanging, it should be tapped one by one in sequence, and the back should be cushioned with a square iron, so that the flanging elevation is flat and the 90-degree line is flat.
2. Strictly follow the duct size tolerance requirements. If the counterpart is obviously misplaced, the insert will be misaligned; the small mouth will fall into the large mouth, which will cause it to fail to fasten or the joint will be skewed and twisted. The inserts should not be deflected obviously, and the opening seam should be in the middle. Regardless of whether the inserts or the flanging of the pipe end bites should be accurate and pressed tightly, the connection joints will be neat and tight in the future.
3. The four-sided tube ends of the flanging should be flush on one side. The small tube can be folded out with a folding machine at one time, and the flanging should be the same width on the entire extension line. This is also necessary for the duct interface to be straight when installing the docking.
4. Except for the iron flange spring clips (including iron flange inserts), which are installed with sealing gaskets on the butting surface of the installation, most of them apply sealant outside the joints after the connection is completed, and clean the seams before applying the glue. The sealant can not be replaced with putty, lime paste, etc., and the special plastic sealing bag for air ducts should be used.
5. The support and hanger for air duct installation shall be set according to the specification requirements. After the air duct is connected, the air leakage test of the air duct shall be carried out according to the requirements of the specification level.
2. Flange connection: For the connection between two sections of air ducts, angle steel flanges are used in China. This labor-intensive and expensive method has been used for many years. The flange connection of air ducts in the air-conditioning project of this building draws on foreign advanced technology and The technology, combined with its own reality, adopts the connection method of TDF and TDC.
1. The TDF connection is that the two ends of the air duct itself form flanges, and then the two sections of air duct are connected by flange angle and flange clamp.
a. The 4 corners of the duct are inserted into the flange corners;
b. Fill sealant evenly around the flange surface formed by the duct edge;
c. The combination of flanges, and the flange clips are inserted from the 4 corners of the flange;
d. 4 flange corner tightening bolts;
e. Clamp the flange clamp together with the two flanges together with a hand vice;
f. If the distance between the flange clamp and the flange angle is 1500mm, use 4 flange clamps; if the flange side length is 900-1200mm, use 3 flange clamps; if the flange side length is 600mm, use 2 flange clamps; If the flange length is less than 450mm, use a flange clamp in the middle.
2. The TDC connection is a plug-in duct flange connection. This connection method is suitable for the connection of the large side length of the air duct between 1500-2500mm.
a. According to the length of the four sides of the air duct, prepare 4 flanges respectively;
b. Four flange strips and four flange corners are inserted into the four sides of the air duct;
c. Check and adjust the flatness of the flange mouth;
d. The flange strip and the air duct are riveted with hollow rivets;
e. The combination of two sections of duct. Fill the flange surface with sealant evenly, combine the two flanges and insert the flange clamp, tighten the bolts at the four flange corners, and finally use a hand vise to clamp the flange clamp together with the two flanges.
f. For larger air ducts on the common floor, when the length of the large side of the air duct exceeds 2500mm, angle steel flanges are still used.
3. Common problems of wind control and safety and their prevention and treatment
(1) The material does not meet the quality requirements
1. Phenomenon: The surface of the plate is uneven, the thickness is uneven, and there are obvious indentations, cracks, blisters, scarring and rust;
2. Harmfulness: When the system is running, the air duct leaks air, causing undue loss of air conditioning load and affecting the service life of the air duct; the surface of the air duct vibrates and generates noise.
3. Reason analysis: Before making the air duct, the quality inspection of the materials used was not carried out; the thickness of the steel plate was not measured.
4. Prevention and control measures: first check the material factory certificate and material quality certificate, then check the appearance of the material; measure the thickness of the steel plate.
(2) Inaccurate warping, twisting and elbow angles of air ducts
1. Phenomenon: The two opposite planes of the rectangular air duct are not parallel, and the two ends are not parallel; the corners are not straight; the diagonals are not equal; the bite is not strict.
2. Harmful: Uneven force on the air duct connection, uneven air duct after installation, loose flange gasket, air leakage in the system, loss of air conditioning load, and shortened service life; affecting air ducts and tuyere The exact installation location.
3. Reason analysis: inaccurate lofting of board blanking; air ducts are parallel in pairs, and the length and width of the sheets on the opposite side are not equal; the width of the bite at the four corners of the air duct is not equal; the setting of the bite seam is wrong, and the bite is manually The seam force is different; no corresponding reinforcement measures have been taken.
4. Prevention and control measures: When unfolding the blanking, the sheet should be strictly squared, and the length, width and inspection diagonal of each sheet should be checked to make their deviation within the allowable range; the blanked sheet, The two sheets on the opposite side of the air duct should be superimposed to check the accuracy of the size; the reserved size of the bite of the sheet must be correct to ensure the same width of the bite; the bite seam is set at the four corners, and the bite seam is manually seamed When it is used, use a wooden hammer to tighten the central parts of both ends of the bite, and then evenly tighten it along the entire length; implement the relevant provisions of the national standard "Code for Construction and Acceptance of Ventilation and Air Conditioning Engineering".
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