【正文】 增濕或干燥等。空調(diào)工程中廣泛使用的噴淋室，可以認(rèn)為是它的一種特殊形式。但是，它也有對水質(zhì)要求高、占地面積大、 水泵 耗能多等缺點(diǎn)：所以，目 前在一般建筑中，噴淋室已不常使用或僅作為加濕設(shè)備使用。 (4)混合式冷凝器 這種設(shè)備一般是用水與蒸汽直接接觸的方法使蒸汽冷凝。內(nèi)裝 固體 填充物，用以貯蓄熱量。換熱分兩個(gè)階段進(jìn)行。第二階段，冷氣體通過火格子，接受火格子所儲(chǔ)蓄的熱量而被加熱。通常用兩個(gè)蓄熱器交替使用，即當(dāng)熱氣體進(jìn)入一器時(shí)，冷氣體進(jìn)入另一器。也用于化學(xué)工業(yè)，如煤氣爐中的空氣預(yù)熱器或 燃燒室 ，人造石油廠中的蓄熱式裂化爐。 陶瓷換熱器 陶瓷換熱器 是一種新型的列管式高溫?zé)崮芑厥昭b置，主要成份為碳化硅，可以廣泛用于冶金、機(jī)械、建材、化工等行業(yè)，直接回收各種 工業(yè)窯爐 排放的 850－ 1400℃ 高溫?zé)煔庥酂?，以獲得高溫助燃空氣或工藝氣體。在結(jié)構(gòu)上成功地解決了熱補(bǔ)償和較好地解決了氣體密封問題。 陶瓷換熱器的生產(chǎn)工藝與窯具的生產(chǎn)工藝基本相同，導(dǎo)熱性與抗氧化性能是材料的主要應(yīng)用性能。 陶瓷換熱器在金屬換熱器的使用局限下得到了很好的發(fā)展， 因?yàn)樗^好地解決了耐腐蝕，耐高溫等課題 。壽命長，維修量小，性能可靠穩(wěn)定，操作簡便。以板代管制成的換熱器，結(jié)構(gòu)緊湊，傳熱效果好，因此陸續(xù)發(fā)展為多種形式。接著英國用 釬焊 法制造出一種由銅及其合金材料制成的 板翅式換熱器 ，用于飛機(jī)發(fā)動(dòng)機(jī)的散熱。在此期間，為了解決強(qiáng)腐蝕性介質(zhì)的換熱問題，人們對新型材料制成的換熱器開始注意。此外，自 60年代開始，為了適應(yīng)高溫和高壓條件下的換熱和節(jié)能的需要，典型的管殼式換熱器也得到了進(jìn)一步的發(fā)展。 換熱器按傳熱方式的不同可分為混合式、蓄熱式和間壁式三類。由于兩流體混合換熱后必須及時(shí)分離，這類換熱器適合于氣、液兩流體之間的換熱。 蓄熱 式換熱器是利用冷、熱流體交替流經(jīng)蓄熱室中的蓄熱體 (填料 )表面，從而進(jìn)行熱量交換的換熱器，如煉焦?fàn)t下方預(yù)熱空氣的蓄熱室。以回收冷量為目的的同類設(shè)備稱蓄冷器，多用于空氣分離裝置中。 間壁式換熱器根據(jù)傳熱面的結(jié)構(gòu)不同可分 為管式、板面式和其他型式。 換熱器中流體的相對流向一般有順流和逆流兩種。逆流時(shí)，沿傳熱表面兩流體的溫差分布較均勻。 在完成同樣傳熱量的條件下，采用逆流可使平均溫差增大，換熱 器的傳熱面積減??；若傳熱面積不變，采用逆流時(shí)可使加熱或 冷卻流體 的消耗量降低。 當(dāng)冷、熱流體兩者或其中一種有物相變化 (沸騰或冷凝 )時(shí)，由于相變時(shí)只放出或吸收汽化潛熱 ，流體本身的溫度并無變化，因此流體的進(jìn)出口溫度相等，這時(shí)兩流體的溫差就與流體的流向選擇無關(guān)了。 在傳熱過程中，降低間壁式換熱器中的熱阻，以提高傳熱系數(shù)是一個(gè)重要的問題。 增加流體的流速和擾動(dòng)性，可減薄邊界層，降低熱阻提高給熱系數(shù)。為了降低污垢的熱阻，可設(shè)法延緩 污垢的形成，并定期清洗傳熱面。 譯文 Fixed tube sheet heat exchanger overview Heat exchanger according to the structure can be divided into: fixed tube sheet heat exchanger, the heat exchangers。 stuffing box type heat exchanger. Fixed tube sheet heat exchanger by both the shell and tube sheet. Because of its simple structure, more extensive use. Fixed tube sheet heat exchanger is a kind of implementation of heat transfer between material of energysaving equipment, is in the oil, chemical, petrochemical, metallurgical, power, light industry, food industry universal application of a process equipment. In oil refining, chemical equipment heat exchanger total equipment number about 40%, accounting for a total investment of 30%45%. In recent years, with the development of energy saving technology, applied domain expands ceaselessly, use of heat exchanger in high temperature and low temperature heat recovery to bring significant economic benefits. Structure principle Fixed tube sheet heat exchanger tube side and a shell side, flowing of fluid with different temperature, heat transfer through the heat exchange is pleted. When the two fluid temperature difference larger, in order to avoid high temperature stress, usually in the proper position on the shell, a pensation coil ( expansion joint). When the shell and tube bundle heat expansion at the same time, pensation ring slow elastic deformation to pensate for the temperature stress caused by thermal expansion. One, fixed tube sheet heat exchanger structure and characteristics 1, fixed tube sheet heat exchanger. Fixed tube sheet heat exchanger is posed of a tube box, shell, tube sheet, pipe and other parts, the structure is pact, exhaust pipe is more, in the same diameter larger, manufacture is simple. Fixed tube sheet heat exchanger structure is arranged in a shell tube, both ends of the pipe bundle by welding or expansion method will pipe fixed on the tube plate, both ends of the tube plate and shell are welded together, shell import and export pipe is directly welded on a casing, pipe plate outer circumference and the cover flange bolts the import and export of pipe, tube and head directly welded together, the tube bundle heat exchanger tube length according to a plurality of baffle. This kind of heat exchanger tubes can be divided into any number of partition process. In 2, the characteristics of fixed tube sheet heat exchanger Fixed tube sheet heat exchanger has the advantages of simple structure, low manufacturing cost, convenient cleaning pipe, tube can be divided into a plurality of process, the shell can be divided into two, wide range of specifications, it is widely used in engineering. Shell cleaning difficulties, for dirty or corrosive medium is used. When the expansion difference is bigger, can be arranged in the casing expansion joint, due to reduced pipe, shell and the thermal stress caused by temperature difference. Fixed tube sheet heat exchanger is characterized by: The smaller, bypass seepage II, fings use less, low cost。 The heat transfer area ratio, heat exchangers 20% ~ 30%. In 3, the disadvantage is the fixed tube sheet heat exchanger: First, shell and tube wall temperature difference, shell and tube wall temperature is t = 50 C, when t = 50 DEG C must be in the shell body setting expansion joint。 The shell can not, mechanical cleaning。 In 3, the mechanical design of fixed tube sheet heat exchanger Fixed tube sheet heat exchanger design except for the most critical heat exchanger plate outside, still have two sides, we called the frame plate and the pressure plate frame plate, lateral not movable wall plate, pressure plate heat exchanger plate on the other side of the tie rod bolt to adjust the position of the wall panels can be used。 column。 the frame plate and the uprig