In order to know the temperature rating of double-walled pipe, we need to figure out what the temperature is resistant to temperature, as well as to the types of double-walled pipe, the double-walled tube the temperature rating is the number?

We usually refer to the temperature levels talking about the operating temperature and temperature rating of double-walled tube. Operating temperature; the temperature is the important parameter through double-walled tube, sometimes referred to as the working temperature setpoint temperature, the casing refers to normal, continuous operation of the temperature, the processing temperature is in front of two double-walled tube capable of contractile reflects the temperature, we take the double-walled tube Φ6 example, the double-walled tube is slowly heated hot air gun, starts when the temperature reaches 84 deg.] C, the start of shrinkage reflects the double-walled tube, then slowly shrink to Φ5, Φ4, when the temperature a final reduction temperature 120 ℃, fully retracted into the double-walled tube [Phi] 3, the above object in a tight, and then heating the machining process is over, and then mounting the double-walled tube parts to put the above air conditioner and the like, for normal working, it's working environment, such as our sleeves normal operating temperature is -55 ℃ to 125 ℃, because we know that a lot of the time, the product will be sold to go around, some local environmental colder, and some the place is hot, then it has a certain scope, our nominal temperature of the product to show that it is working properly at this temperature, once Live a normal temperature, it may not be able to guarantee the life and not be able to work properly, we are here talking about normal temperature heat shrink tubing is double-walled pipe insulation can play a temperature protection, over this temperature will not be able to play a role;

Next we will talk about what temperature levels have double-walled tube?

When double-wall heat shrinkable tube shrink than to know that we have learned classification of double-walled tube: green double-walled tube; thick soft rubber cold shrink double-walled pipe; double-wall thick-walled tube; military standard double-wall tube; automotive wiring harness half hard type double-walled tube; double-walled tube of high shrinkage ratio. Corresponding to the temperature levels we are double-walled tube: temperature 110 ℃ double-walled tube, temperature 125 ℃ double-walled tube, double walled tube temperature 135 deg.] C. Of course, special requirements, short term or double-walled tube require a relatively high temperature to achieve some long term, can special order.

Performance of the double-walled heat shrink tubing:

characteristic vehicle for heat-shrinkable tube is: a heat-shrinkable, double-walled, the hot melt adhesive double plastic tube.

Such double-wall heat shrinkable tube is divided into outer and inner layers, the outer layer of high pressure low density polyethylene and ethylene - vinyl acetate copolymer mixture (EVA), the inner layer is very thin hot-melt adhesive glue seal resin. When the tubing set into the surface of such a double-wall heat shrinkable tubing diameter larger than the tube state, positioned after the heating, the double-walled heat shrink tubing will shrink to a predetermined size, the inner layer by hot melt adhesive, the heat shrinkable tube and tubing close together, without any intermediate gaps. This pipeline protection methods can greatly improve the life of the tubing.

Use of double-wall heat shrinkable tube:

the first double-wall heat shrinkable tube shrink tube heat shrinkable tube wall is only a single one this time, mainly used in electrical equipment and cooling equipment as a protective electrical connector. Later, the United States Raychem (Raychem) company, dedicated to the production of the automotive industry, double-wall heat shrink tubing. Because not only provides excellent corrosion resistance, but also provides protection and friction parts related parts, and is especially suitable for compact small car, it has been widely used in Japan and South Korea of Japanese models. In particular vehicle chassis parts are fitted with double-wall heat-shrinkable tube, effectively prevents the corrosion of sand and mud brake tubing.

In addition, as the double heat shrinkable tube with high hardness and wear resistance, a protective pipe is formed in the outer layer, to avoid direct friction with other parts of the steel, so many foreign car companies are specified: the installation of bis layer portion of heat shrink tubing allows for interference between parts. Now more and more small-scale installation of high-power engine on the market as well as "ABS" and power steering, a small space is also more crowded, brake tubing arrangement also become more complex, often between the tubing as well as interference problems between the tubing and related parts, particularly the installation of a "ABS" bundled tubing portion 6 is difficult to ensure sufficient clearance between the tubing, thereby causing friction between the tubing and the bump is indeed very big security risk, use double-wall heat shrink tubing make this issue the appropriate solution.

Double-wall heat shrinkable tube quality:

Since the double-wall heat shrinkable tube heat shrinkable tube has played such an important role, so the quality of the double-wall heat shrink tubing is crucial, the use of counterfeit heat shrink tubing will result in fatal consequences. For example: There are some temperature interval between the thermal shrinkage temperature of the heat shrinkable tube with high softening and melting temperature of the heat-shrinkable tube, so the heat shrink tubing and then heat shrinking process to maintain good any form, with the movement on the warming region the air inside the heat-shrinkable tube may be evacuated. But inferior in heat shrink tubing while heating to a temperature of shrinkage has been softened and melted, so often the air is enclosed in the heat shrinkable tube, the performance of the surface of the heat-shrinkable tube Gegedada, it is necessary to eliminate the bubbles shrink tube in a softened state in when using needle garish deflated, because thermal shrinkage during cooling of the tube, which pinhole formation of many voids in the heat-shrinkable tube and scarring the surface, and therefore inferior heat shrink tubing reach the protective effect of the tubing.

Further only in a radially contracted, substantially no axial contraction Eligible heat shrink tubing in heat shrinkage, after machining the finished good consistency, while the poor thermal shrinkage tube axially only large, even axial elongation , heat shrinkable tube finished level after processing missing. Phenomenon often occurs when the pipe clamp is not installed on the assembly line is often the cause of poor quality is to use heat-shrinkable tubing. In this case, measures often used an elongated blade to cut the heat-shrinkable tube, the upper surface of the problem is solved, in fact, greater damage to the tubing as the tubing during operation will scratch organic coating , resulting in tubing coating completely destroyed. Therefore, the quality of heat shrink tubing is essential.

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汽车专用双壁热缩管的耐温等级介绍

要想知道双壁管的耐温等级，首先我们要弄明白耐温是耐什么温度，以及有哪几类双壁管，这些双壁管的耐温等级各是多少？

我们通常所说的耐温等级讲的是双壁管的工作温度及额定温度。工作温度；这个温度是贯穿双壁管重要的一个参数，工作温度有时也指额定温度，就是指套管能够正常的、连续的工作的温度，前面两个温度是指加工双壁管能够起收缩反映时的温度，我们还是拿Φ6双壁管举例，把双壁管用热风枪慢慢加热，当温度开始达到84℃，双壁管开始起收缩反映，然后慢慢收缩到Φ5、Φ4，当温度达到终缩温度120℃，双壁管完全收缩到Φ3，紧紧地缩在物体上面，然后加工加热这个过程就结束了，然后把套上双壁管的这个零部件安装到空调等上面，进行正常的工作，它的正常工作环境，比如说我们套管的正常工作温度为-55℃到125℃，因为我们知道，很多时候，产品会销售到各地去，有的地方环境比较寒冷，有的地方比较炎热，那么它都有一定的适用范围，我们的产品温度的标称就表明其在这个温度下都是可以正常使用的，一旦超过正常使用温度，就不一定能够保证寿命，不一定能正常工作，我们这里说的正常温度热缩管就是双壁管能够起到绝缘防护的温度，超过这个温度就不一定能够起到作用；

接下来我们就来谈谈双壁管有哪些耐温等级？

在了解热缩双壁管收缩比的时候我们已经了解到双壁管的分类：环保双壁管；柔软厚胶低温收缩双壁管；厚壁双壁管；军标双壁管；汽车线束半硬型双壁管；高倍率收缩双壁管。对应的我们双壁管的耐温等级有：耐温110℃双壁管、耐温125℃双壁管、耐温135℃双壁管等。当然如有特殊要求，短期内或者长期内需要双壁管达到某种比较高的温度，可以特殊订制。

双壁热缩管的性能：

汽车专用热缩管的特性为：热收缩、双层壁、内有热熔型胶粘剂的双层塑料管。

这种双壁热缩管分为内外两层，外层为低密度高压聚乙烯和乙烯-醋酸乙烯共聚合物（EVA）的混合物，内层是很薄胶黏性很强的热熔型密封树脂。当这种双壁热缩管以大于油管直径状态下套入油管表面，定位后再加热，双壁热缩管便会收缩到预定尺寸，通过内层的热熔胶，把热缩管和油管紧密的连接在一起，中间没有任何间隙。这种油管保护方法，可使油管的使用寿命大大提高。

双壁热缩管的使用：

最初热双壁热缩管缩管只有单壁热缩管这一种的时候，主要是应用在电器设备和制冷设备上作为电气接头的保护。后来美国Raychem（瑞侃）公司，生产处专用于汽车行业的双壁热缩管。由于不仅提供了优良的防腐性能，还提供了与相关零件摩擦部位的防护，因此特别适用于结构紧凑的小型汽车，所以在日本和韩国的日系车型中被大量使用。特别是在车辆底盘部位都加装了双壁热缩管，有效的防止了砂石及泥水对制动油管的腐蚀。

另外由于双层热缩管有较高的硬度和耐磨性能，在油管外面形成一种保护层，避免了钢管与其他零件的直接摩擦，因此许多国外的汽车公司都规定：在加装了双层热缩管的部位允许零件之间的干涉。现在市场上的小型加装大功率发动机以及“ABS”和助力转向的越来越多，是的狭小的空间也更加拥挤，制动油管的布置也变得越来越复杂，经常出现油管之间以及油管与相关零件之间的干涉问题，特别是加装了“ABS”部位6支油管捆绑在一起很难保证油管间有足够的间隙，由此造成油管之间的磕碰和摩擦，确实是极大的安全隐患、双壁热缩管的应用使这一问题得到相应的解决。

双壁热缩管的质量：

由于双壁热缩管高温热缩管起到如此重要的作用，因此双壁热缩管的质量就至关重要，伪劣热缩管的使用将造成致命的后果。例如：优质热缩管的加热收缩温度与热缩管软化熔融温度之间有一段温度的区间，因此热缩管在加热收缩过程中任然保持较好的形态，随着加温区域的移动就可以将热缩管内部的空气排空。但是劣质热缩管在加热到收缩温度的同时已经软化熔融，因此经常有空气被封闭在热缩管中，表现为热缩管表面的疙疙瘩瘩，为了消除气泡就需要在热缩管处于软化状态的时候用钢针扎眼放气，因为热缩管冷却过程中的收缩，这些针眼在热缩管表面形成许多疤痕和空洞，因此劣质热缩管达不到对油管的保护作用。

另外合格的热缩管在加热收缩时只是在径向收缩，轴向基本不收缩，加工后成品一致性很好，而劣质热缩管不仅轴向收缩很大，甚至还有轴向伸长的，加工后的成品热缩管层次不齐。在装配线时经常发生油管卡子装不上的现象往往就是使用了劣质热缩管的原因。在这种情况下往往采取用刀片伸长出的热缩管切掉的措施，表面上问题解决了，实际上对油管的伤害更大，因为在操作过程中会有油管的有机涂层刮伤，造成油管涂层的完全破坏。因此热缩管的质量至关重要。