腐蝕問題一直是自控儀表中的難題,危害十分嚴(yán)重,有的自動化系統(tǒng)因此不得不改為手動,而且還得頻繁地更換被腐蝕的儀表及設(shè)備。因此,耐腐蝕問題一直是國內(nèi)外廠家及設(shè)計院關(guān)注的問題。
Corrosion has always been a difficult problem in automatic control instruments, and the harm is very serious. Therefore, some automatic systems have to be changed to manual, and corroded instruments and equipment have to be replaced frequently. Therefore, corrosion resistance has always been a concern of domestic and foreign manufacturers and design institutes.
一、耐腐蝕材料
1、 Corrosion resistant materials
(1)橡膠有一定的耐腐蝕性,而且價格便宜。因此在溫度不高的情況下被廣泛地用在耐腐蝕設(shè)備的調(diào)節(jié)閥上,五、六十年代便產(chǎn)生出了襯橡膠的隔膜閥。為調(diào)節(jié)大流量的腐蝕介質(zhì),進而又產(chǎn)生了襯膠蝶閥。但橡膠并不完全耐腐蝕,且使用溫度,耐壓條件受到一定的限制。
(1) Rubber has certain corrosion resistance and is cheap. Therefore, it is widely used in regulating valves of corrosion resistant equipment under low temperature. In the 1950s and 1960s, rubber lined diaphragm valves were produced. In order to regulate the corrosive medium with large flow, a rubber lined butterfly valve is produced. However, the rubber is not completely corrosion resistant, and the use temperature and pressure conditions are limited.
(2)聚四氟乙烯(外文簡稱為F4、PTFE),是當(dāng)今好的耐腐蝕材料,被稱為“耐腐蝕”。它具有非常優(yōu)良的耐蝕和耐熱性能,可在-250~250℃溫度內(nèi)長期使用。除在高溫高壓下氟元素和熔融狀態(tài)的堿金屬對它有腐蝕作用,某些鹵化物或芳香烴使其有輕微的膨脹外,其它諸如強酸(包括濃硝酸和水)、強堿、強氧化劑、油脂、酮、醚、醇等即使在高溫下也對它不起作用。它幾乎可以抵抗所有化學(xué)介質(zhì)而不受其腐蝕。
(2) Polytetrafluoroethylene (F4, PTFE for short in foreign languages) is a good corrosion resistant material today, known as the "king of corrosion resistance". It has excellent corrosion resistance and heat resistance, and can be used for a long time at - 250~250 ℃. Except that fluoride and molten alkali metal corrode it under high temperature and pressure, and some halides or aromatic hydrocarbons cause slight expansion, other strong acids (including concentrated nitric acid and aqua regia), strong alkalis, strong oxidants, oils, ketones, ethers, alcohols, etc. do not affect it even under high temperature. It can resist almost all chemical media without being corroded.
(3)聚四氟乙丙烯是一種耐腐蝕、耐溫性能更好的新型材料,具有高度的化學(xué)穩(wěn)定性和優(yōu)良的耐化學(xué)腐蝕力,如耐強酸、強堿、強氧化劑等。它還有突出的耐熱、耐寒性,可長期使用在溫度-00~250℃環(huán)境下;同時,還有不粘連、不吸水、不燃燒等特點。此外,該材料具有較好的流動性,可內(nèi)襯于部件表面作為耐腐蝕材料使用。
(3) Polytetrafluoroethylene propylene is a new material with better corrosion resistance and temperature resistance, which has high chemical stability and excellent chemical corrosion resistance, such as strong acid, strong alkali, strong oxidant, etc. It also has outstanding heat resistance and cold resistance, and can be used for a long time under the temperature of - 00~250 ℃; At the same time, there are no adhesion, no water absorption, no combustion and other characteristics. In addition, the material has good fluidity and can be lined on the surface of components as a corrosion resistant material.
(4)早在二三十年代,國外便有耐蝕合金如哈氏合金、蒙乃爾合金,而國內(nèi)五六十年代才起步。把耐腐蝕合金用在調(diào)節(jié)閥領(lǐng)域是從八十年代開始的,但因耐腐蝕合金價格太貴而無法被廣泛推廣使用。
(4) As early as the 1920s and 1930s, there were corrosion resistant alloys such as Hastelloy and Monel abroad, but in the 1950s and 1960s, they started in China. The use of corrosion-resistant alloys in the field of control valves began in the 1980s, but the price of corrosion-resistant alloys is too expensive to be widely used.
二、耐腐蝕閥系列
2、 Corrosion resistant valve series
(1)全四氟耐蝕單座調(diào)節(jié)閥
(1) Full tetrafluoro corrosion resistant single seat regulating valve
全四氟耐腐蝕單座調(diào)節(jié)閥采用金屬外殼與聚四氟乙烯鑲嵌的結(jié)構(gòu)形式。金屬外殼一般用碳鋼或不銹鋼,閥體內(nèi)部與介質(zhì)接觸的部分(容腔、通道、節(jié)流件等)全部采用聚四氟乙烯,將閥體材料與腐蝕性介質(zhì)隔離開來,從而使腐蝕性問題得到了較好的解決,尤其是在硫酸、鹽酸、濕氯氣等介質(zhì)中使用效果尤為突出。該產(chǎn)品于92年獲得了國家。
The metal shell and PTFE inlaid structure form are adopted for the all PTFE corrosion resistant single seat regulating valve. The metal shell is generally made of carbon steel or stainless steel. The parts inside the valve body that are in contact with the medium (chamber, channel, throttle parts, etc.) are all made of PTFE, which separates the valve body material from the corrosive medium, so that the corrosive problem can be solved better, especially in sulfuric acid, hydrochloric acid, wet chlorine and other media. This product obtained the national patent in 92.
(2)襯氟O型球閥
(2) Fluorine lined O-ring ball valve
襯氟球閥又稱水處理專用球閥,主要用于強堿、水處理(脫鹽水)的兩位控制裝置中。它采用內(nèi)襯氟塑料方式,將耐腐蝕材料內(nèi)襯于閥體內(nèi),保證與各種強腐蝕介質(zhì)接觸的部分均為氟塑料,將腐蝕介質(zhì)與閥體材料隔離開;在結(jié)構(gòu)上,由于球閥的球芯是一個剛度好、可靠性好的零件,從根本上解決了過去隔膜閥的隔膜片不可靠的缺陷,提高了閥的可靠性并延長了使用壽命。因此,襯氟球閥是替代隔膜閥的佳產(chǎn)品。
Fluorine lined ball valve, also known as special ball valve for water treatment, is mainly used in the two position control device for strong alkali and water treatment (desalted water). It is lined with fluoroplastics, and the corrosion-resistant materials are lined in the valve body, so as to ensure that the parts contacting with various strong corrosive media are fluoroplastics, which separates the corrosive media from the valve body materials; In terms of structure, the ball core of the ball valve is a part with good rigidity and reliability, which fundamentally solves the problem of unreliable diaphragm of diaphragm valve in the past, improves the reliability of the valve and extends its service life. Therefore, fluorine lined ball valve is a good substitute for diaphragm valve.
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