Thaum PFA (Perfluoroalkoxy) Sheath rhaub yog siv los boil 37% Hydrochloric Acid ntawm 85 degree, Dab tsi yog qhov siab tshaj plaws ntawm phab ntsa tuab los tiv thaiv thermal degradation ntawm Polymer ntawm Resistance Wire Interface?
Tso lus
Nyob rau hauv boiling 37% hydrochloric acid ntawm 85 degree, PFA (perfluoroalkoxy) sheath heaters cia siab rau lub polymer cov tshuaj tiv thaiv. Txawm li cas los xij, qhov ntsuas kub ntawm cov hlau tsis sib haum yog siab dua li qhov kub ntawm cov kua qaub vim yog cov cua sov. PFA pib mos ntawm 260℃thiab degrades sai tshaj 300 degree. Qhov siab tshaj plaws tso cai phab ntsa tuab kom cov hlau sib txuas kub hauv qab 260℃yog 1.0 hli rau lub zog ceev ntawm 10 W / cm². Cov phab ntsa Thicker nce qhov kub thiab txias thoob plaws PFA, tsa cov hlau kub thiab ua rau cov polymer degradation.
Mechanism ntawm Thermal Degradation hauv PFA Sheaths
Qhov kub poob thoob plaws PFA phab ntsa yog ΔT=(q × t) / k, qhov twg q yog cua sov flux, t yog phab ntsa thickness, thiab k yog PFA thermal conductivity (0.25 W / m·K). Rau cov kua qaub kub ntawm 85 degree, 1.0 hli phab ntsa ntawm 10 W / cm² muab ΔT=(100,000 × 0.001) / 0.25=400 degree, ua rau cov hlau kub ntawm 485℃-zoo tshaj li 260℃softening point. Txawm li cas los xij, qhov kub ntawm cov hlau yuav tsum raug xam kom raug; cov qauv saum toj no qhia tau hais tias txawm tias 1.0 mm yog tuab heev. Hauv kev xyaum, PFA cov cua sov xav tau ntau cov phab ntsa nyias.
Quantitative Wire Temperature raws li kev ua haujlwm ntawm phab ntsa Thickness
Rau boiling 37% HCl ntawm 85℃nrog 10 W / cm² zog ceev:
| Phab ntsa Thickness (mm) | ΔT Hla PFA (degree) | Hlau Kub (degree) | PFA Txoj Cai |
|---|---|---|---|
| 0.2 | 80 | 165 | Muaj kev nyab xeeb |
| 0.3 | 120 | 205 | Muaj kev nyab xeeb |
| 0.4 | 160 | 245 | Safe (ze li txwv) |
| 0.5 | 200 | 285 | Degradation pib |
| 0.6 | 240 | 325 | Kev degradation hnyav |
| 0.8 | 320 | 405 | Kev ua tsis tiav sai |
Phau Ntawv Qhia Phab Ntsa Thickness Ntau Tshaj
| Lub zog ceev (W / cm²) | Maximum Phab Ntsa Thickness (mm) rau Hlau Temp<260°C | Phab ntsa pom zoo (mm) |
|---|---|---|
| 5 | 0.7 | 0.5 |
| 8 | 0.45 | 0.4 |
| 10 | 0.35 | 0.3 |
| 12 | 0.3 | 0.25 |
| 15 | 0.25 | 0.2 |
Ua ib qho kev qhia tshwj xeeb
Rau lub rhaub PFA hauv boiling 37% HCl ntawm 85 degree, qhia ib phab ntsa thickness ntawm 0.3-0.4 hli kom cov hlau kub hauv qab no 260℃ntawm 10 W / cm². Cov phab ntsa tuab dua yuav ua rau thermal degradation ntawm PFA ntawm cov hlau sib txuas. Los ntawm kev tswj cov phab ntsa thickness, tus engineer tiv thaiv polymer tsis ua hauj lwm.
