What is a bellows?
1. The classification of bellows:
The bellows can be roughly classified from the following three aspects:
1, according to the number of layers, it can be divided into single-layer metal bellows and double-layer metal bellows。 The single layer bellows have superior impact and compression resistance, while the double deck bellows are smaller than those of single-layer ones。 But no matter how it is classified, the quality of metal bellows is well known。
2, from the forming process of the classification of metal corrugated pipe can be divided into rolling forming, hydraulic forming mode, forming and welding deposition forming metal bellows, these are the advantages of the source in the metal bellows its good plasticity and toughness, so businesses can according to the needs of different sizes, the corrugated corrugated pipe design into different shapes suitable for use, performance and effect of different methods of metal corrugated pipe is pressed into a different.
3。 According to the use of welded metal bellows, it can be divided into air tightness type and winding type。 Air tight water density is a kind of metal bellows that specializes in gas gas or water heater。 It has good sealing ability and can avoid leakage of air leakage。 The winding metal bellows are mostly used to make the bellows of the magnetic card telephone or desk lamp, and the safety of this kind of bellows is very high。
翡翠棋牌Two. The main points of the use of bellows
Although the metal corrugated pipe culvert has many advantages, but if the installation is improper or the use is unreasonable, it can not achieve the ideal effect, and even bring economic loss. It is necessary to pay attention to the use of or modification
1, prevent the metal corrugated pipe culvert to bear the twisted shear, and should pay special attention to the screw joint nut.
2. The actual bending radius R is selected reasonably. R can be pressed to select: R=KRmin. The minimum bending radius is allowed for the bellows. K is a coefficient of experience. The K value is too small and the hose diameter is bending repeatedly. It is easy to produce fatigue damage and stress concentration. The K value is too large, which causes the waste of materials and brings difficulties to the layout. It is generally in 1~2. 2 within the range.
3, in the use of the process, to ensure that the hose weave net sleeve is not subject to mechanical damage such as knock, touch, grinding, collision and so on。
4, the correct selection of the nominal length of the metal bellows L。 The price of the bellows is higher and the length is too long, which will increase the unnecessary investment, increase the flow resistance, and may also cause additional vibration。 But the length is not enough, easy to bend in the weld joint, the metal bellows can not work in the natural bending state, the service life will be shortened。 The metal bellows for vertical movement configuration of two parallel segments should be pressed to determine: L=4R ten 0。 The 5S+ type: R a hose actual bending radius; a S corresponding to the hot plate in the opening and closing position of the distance between a hot plate opening height; a closed position and fixed ends of the hose center。 It is obvious that the fixed end of the metal bellows is set at the center height of the press and closed position, and the L is the shortest。
Three. The advantages of the bellows in Guizhou as the prestress metal bellows
1, the prestressed metal bellows with double thread, strong Phoenix stiffness than the single thread performance is good。
2。 Good adhesion to concrete and strong adaptability in engineering。 To ensure the steel wire channel has better quality, reach the line straight, smooth curves, steel beam for long-span bridges, its superiority is more prominent。
3, the loss of pipe friction is small. Due to the point contact between the prestressed metal bellows and the steel strands, the friction coefficient and the deviation coefficient of the pipe are small, thus reducing the friction loss and increasing the effective prestress. After many tests, the friction coefficient of the steel strand and the pipe wall is 0. 16~0. 22, the average is 0. 19; the deviation coefficient K value is (0. 6~1. 0) X10 a sl. The average is o. 8x10 a 3Zm. 4. The prestress metal bellows have high efficiency and remarkable economic benefit. The use of bellows can ensure the quality of the project, easy to operate, easy to wear, shorten the time limit, save investment, and have significant economic benefits.
四、使用金属波纹管的注意事项 采用金属波纹管能保证预应力管道有好的质量,并利于穿束,保证钢束位置。 1、由于卷好的金属波纹管长度较长,体积较大,一般是工程单位向厂方提规格、数量,由厂方带设备及材料到施工现场加工。这样既可大大减少波纹管的损耗(短头、碰伤、锈蚀等),又能满足需方的各项要求,并节约经费。 2、金属波纹管现场卷制好后,应存放在千燥场地,下面用档距为1。6m的木板多档架空,上面覆盖防雨油布等遮盖物,堆放高度不宜超过7m。 3、搬运过程中轻拿轻放,不得同其它材料、设备混装。如一次施工用量大,可使用木框架装运,而不宜直接用钢丝绳大捆绑扎吊运。 4、金属波纹管安装后,不得在管子上面堆放其它材料和杂物,以免管道受到碰压变形。
Four, attention should be paid to the use of metal bellows. Metal bellows can ensure good quality of prestressed pipes, and facilitate wear and ensure the location of steel bunches. 1, as the rolled metal bellows are long and large in volume, the general specification is for the engineering units to make specifications and quantities to the factory, and the factory will bring the equipment and materials to the construction site. This can greatly reduce the loss of bellows (short head, bruise, corrosion, etc.), and can meet the requirements of the demand side, and save funds. 2, metal bellows site rolled, should be stored in a dry place, the span is 1. 6m board file overhead, covered with tarpaulin rain cover, stacking height should not exceed 7m. 3, in the process of handling gently, not with other materials, mixing equipment. If a large amount of construction is used, it can be shipped with a wooden frame, but it is not suitable to be directly tied with a wire rope. 4. After the installation of the metal bellows, no other materials and sundries should not be stacked on the pipe, so as to prevent the pipe from being pressed and deformed.