聯(lián)系電話
135 8826 8698
新聞動態(tài)
化工泵液態(tài)烴泵機(jī)械密封選用要求及注意事項
2019-07-25 10:39
化工泵的種類很多，具有耐腐性能的離心泵，磁力泵。對于特殊工況中液態(tài)烴泵的使用機(jī)械密封的選用很重要，液態(tài)烴介質(zhì)是一種低溫液化氣體，具有低沸點(diǎn)、低粘度、高蒸汽壓等特性。在這種工況下應(yīng)用的機(jī)械密封，會使密封材料出現(xiàn)冷脆性，大氣中的水汽會在密封裝置的大氣側(cè)面上凍結(jié)，摩擦副端面液膜容易汽化等。尤其是當(dāng)介質(zhì)稍有泄漏，漏出的液態(tài)烴在大氣側(cè)立即汽化，帶走大量熱，機(jī)械密封環(huán)境溫度急劇下降，使用一般的密封材料，如橡膠或聚四氟乙烯普遍變脆，導(dǎo)致密封失效，泄漏增大而不可收拾。
There are many kinds of chemical pumps, such as centrifugal pumps and magnetic pumps with corrosion resistance. The selection of mechanical seals for liquid hydrocarbon pumps under special conditions is very important. The liquid hydrocarbon medium is a low temperature liquefied gas with low boiling point, low viscosity and high vapor pressure. The mechanical seal used under this condition will make the sealing material appear cold brittle, the water vapor in the atmosphere will freeze on the side of the sealing device, and the liquid film at the end of the friction pair is easy to vaporize. Especially when the medium leaks slightly, the leaked liquid hydrocarbon vaporizes immediately at the atmospheric side, takes away a lot of heat, and the temperature of mechanical seal environment drops sharply. The use of general sealing materials, such as rubber or PTFE, generally becomes brittle, leading to seal failure, leakage increases and irremediable.
所以在選擇液態(tài)烴泵時機(jī)械密封使用要求及注意事項很重要，有些企業(yè)采用雙端面機(jī)械密封，在介質(zhì)和大氣端設(shè)一隔離室，其間通以封油以緩和低溫的影響。但這種結(jié)構(gòu)復(fù)雜且需配封液系統(tǒng)。據(jù)經(jīng)驗，使用波紋管機(jī)械密封比較好，主要表現(xiàn)在用屬波紋管和柔性石墨代并輔助密封圈，解決了密封圈材料發(fā)生冷脆而失彈及緩沖作用的問題，如DBM型、YH604/606/609型等。
So it is very important to use mechanical seal when choosing liquid hydrocarbon pump. Some enterprises adopt double-end mechanical seal and set up an isolation chamber at the media and atmosphere end, during which oil is sealed to alleviate the effect of low temperature. But this kind of structure is complex and needs sealing fluid system. According to experience, it is better to use bellows mechanical seals, which are mainly manifested in replacing bellows and flexible graphite with auxiliary sealing rings. The problems of cold brittleness, elasticity loss and cushioning of sealing ring materials are solved, such as DBM type, YH604/606/609 type, etc.
1、金屬波紋管材料選用耐低溫、塑性及韌性好的哈-C,AM350，Carpenter20等;
1. Metal bellows are made of Ha-C, AM350 and Carpenter 20 with good low temperature resistance, plasticity and toughness.
2、由于在低溫條件一下，摩擦副端面的汽化對機(jī)械密封，性能影響很大，除選取較合適的材料外，合理選用端面比壓(主要是波紋管的壓縮量，一般比通常使用中所給的壓縮量大15%一30%為宜)，在機(jī)械密封元件靠近大氣側(cè)通入25℃左右的冷卻水，以改善摩擦副潤滑環(huán)境。
2. Because the vaporization of the end face of the friction pair has a great influence on the performance of the mechanical seal at low temperature, besides choosing suitable materials, it is advisable to reasonably select the specific pressure of the end face (mainly the compression of the bellows, which is 15% to 30% larger than the compression that is usually given in use). The mechanical seal element is put into the air side at 25 C. About the cooling water to improve the lubrication environment of friction pairs.
3、摩擦副l材料在兩種特殊情況下選用:
3. Material of friction pair L is selected in two special cases:
a.對連續(xù)運(yùn)轉(zhuǎn)的設(shè)備，介質(zhì)內(nèi)若含較多的固體顆粒，此時選用“硬對硬”結(jié)構(gòu)(在實際中選了YG6-YG6)較好，一般連續(xù)運(yùn)轉(zhuǎn)壽命8000h以上;
For continuous operation equipment, if there are more solid particles in the medium, the "hard-to-hard" structure (YG6-YG6 is selected in practice) is preferable. Generally, the continuous operation life is more than 8000 hours.
b.對間歇性的運(yùn)轉(zhuǎn)一設(shè)備，摩擦副選用碳化鎢或碳化硅對特種石墨。
B. For intermittent running equipment, tungsten carbide or silicon carbide are selected as friction pairs for special graphite.
