This hot tube heat exchanger is mainly composed by frame, hot tube, tube plate, smoke box, and other accessories.

This heat exchanger is vertically positioned, and the hot tubes are vertically arranged on the tube plate. When working, the cold fluid and cold fluid are flowing in reverse directions. With the orifice plate on the heat exchanger as the boundary, one side is the channel of hot fluid and the other side is the channel of cold fluid. The heat from the hot fluid is transferring to the cold fluid through the hot tubes. In this way, the air and gas are heated. The orifice plate is parallel with the gas flow direction. For the convenience of transportation, one set of equipment can be disassembled into several parts. In view of the sealing performance of the equipment, each equipment is an independent whole, and they will be assembled into a whole set of equipment on the site.

Hot tube is a kind of heat transfer element with high thermal conductivity. It transfers heat through the evaporation and condensation of working medium in the fully enclosed vacuum shell. It has a series of advantages, such as extremely high thermal conductivity, good isothermal characteristics, heat flux isothermal characteristics, heat transfer in remote distance, and controllable temperature. The hot tube heat exchanger composed by hot tubes has the advantages of high heat transfer efficiency, compact structure, small fluid resistance loss, easy control of dew point corrosion, etc. At present, hot tubes and hot tube heat exchangers have been widely applied in metallurgical, petrochemical industry, electric power, ceramics, transportation, textile, machinery, and other industries. They have been used as the energy saving equipments in the utilization of heat energy in waste heat recovery and technological process. Obvious economic benefits have been achieved.

Typical gravity hot tube is shown in Fig.1. Firstly vacuum the enclosed tube, and fill in suitable amount of working medium at this state. After absorbing heat, the working medium will be transferred into steam with the form of evaporation and boiling. Under the effect of pressure difference, the steam will condensate into liquid after rising to the heat releasing section of the hot tube, and its heat will be transferred to heat released cold fluid. The condensed liquid will return to the heating section along the inner wall of the hot tube under the effect of weight.

It will vaporize again after being heated. Cycling like this, the heat will be continuously transfers from one end to the other. The thermal resistance in the hot tube is very small due to the heat transfer by phase changing. Compared with silver, copper, aluminum and other metals, the hot tube with unit weight can transfer heat with several orders of magnitude more than that of metals. So, small temperature difference can acquire larger heat transfer rate. It also has the characteristics of simple structure and one-way heat conduction. Due to the special mechanism of hot tube, the heat exchange between hot fluid and cold fluid is realized outside the tube, and this is convenient for enhanced heat transfer. In addition, the internal of hot tube is generally vacuumized, so the working medium can be easily boiled and evaporated, so the hot tube can be started very quickly.

The heat transfer element of hot tube can be used with one piece and in combination. According to the conditions of the user’s site, it can be formed into various types of heat exchangers while equipping with corresponding flow structures. Hot tube heat exchanger has the advantages of high heat transfer efficiency, small resistance loss, compact structure, reliable working, low maintenance cost, etc. It has been widely used in space technology, electronics, metallurgy, power, petroleum, chemical and other industries. Hot tube heat exchanger can be divided into integral type, separate type and combined type.

 

Beijing Chinese Translation Service Company has translated many documents about Integral Hot Tube Air and Gas Heat Exchanger.

 

该热管换热器主要由框架、热管、管板、烟箱及部分附件组成。

本换热器为立式布置，热管垂直布置在管板上。工作时热流体和冷流体逆方向流动，以换热器中孔板为分界线，一侧为热流体通道，另一侧为冷流体通道，通过热管将热流体热量传给冷流体侧，即而将空、煤气加热。孔板与气流流向保持平行，方便运输前提下，一套设备分解成几个部分，考虑设备的密封性，每台设备都是独立的整体，现场组对成整套设备。

热管是一种具有高导热性能的传热元件，它通过在全封闭真空壳内工质的蒸发与凝结来传递热量，具有极高的传热性、良好的等温性、热流密度等温性、可远距离传热、可控制温度等一系列优点。由热管组成的热管换热器具有传热效率高、结够紧凑、流体阻力损失小、有利于控制露点腐蚀等优点。目前热管及热管换热器已广泛应用于冶金、石油化工、电力、陶瓷、交通、轻纺、机械等行业中，作为废热回收和工艺过程中热能利用的节能设备，取得了显著的经济效益。

典型的重力热管如图所示，在密闭的管内先抽成真空，在此状态下充入适量工质，工质吸热后以蒸发与沸腾的形式转变为蒸汽，在压差作用下，在升至热管放热段结成液体，其热量传递给放热冷流体。冷凝液在重力的作用下，沿热管内壁返回到受热段，

并再次受热汽化，如此循环往复，连续不断的将热量由一端传向另一端。由于是相变传热，因此热管内热阻很小，热管的高导热能力与银、铜、铝等金属相比，单位重量的热管可多传递几个数量级的热量，所以能以较小的温差获得较大的传热率，且结构简单，具有单向导热的特点，特别是由于热管的特有机理，使冷热流体间的热交换均在管外进行，这就可以方便地进行强化传热。此外，由于热管内部一般抽成真空，工质极易沸腾与蒸发，热管启动非常迅速。

热管这种传热元件，可以单根使用，也可以组合使用，根据用户现场的条件，配以相应的流通结构组合成各种形式换热，热管换热器具有传热效率高、阻力损失小、结构紧凑、工作可靠和维护费用少等多种优点，它在空间技术、电子、冶金、动力、石油、化工等各种行业都得到了广泛的应用。热管换热器又分为整体式、分离式和组合式。

 

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