Lunchbox ice packs yog cov khoom siv cua txias uas siv dav hauv kev khaws zaub mov, kev thauj mus los kho mob, thiab tub yees txhua hnub. Lawv lub hauv paus ntsiab lus cua txias feem ntau yog nyob ntawm qhov nqus cua sov thaum lub sijhawm hloov pauv ntawm cov khoom siv tshuaj refrigerant sab hauv, yog li tswj hwm qhov qis - qhov kub thiab txias. Kab lus no yuav tham txog cov ntsiab lus ntawm cov tshuaj lom neeg tseem ceeb thiab lawv cov txheej txheem ntawm kev ua ntawm cov khoom noj khoom haus noj su.
Lub ntsiab Chemical Compositions
Lunchbox ice packs feem ntau siv hom tshuaj lom neeg hauv qab no ua cov tub yees:
1. Inorganic ntsev Hydrate
Cov ice pack refrigerants feem ntau yog aqueous daws ntawm ammonium nitrate (NH₄NO₃) lossis ammonium chloride (NH₄Cl). Cov ntsev no tau txais cov tshuaj tiv thaiv endothermic thaum yaj hauv dej, ua rau poob qis hauv qhov kub thiab txias. Piv txwv li, ammonium nitrate absorbs mus txog 26.5 kJ / mol ntawm tshav kub thaum yaj, txaus kom txo cov tshuaj kub hauv qab 0 degree. Tsis tas li ntawd, sodium acetate (CH₃COONa) trihydrate (CH₃COONa·3H₂O) kuj yog ib qho kev tivthaiv, uas tshwm sim los ntawm kev hloov pauv hloov pauv, txhais tau tias nws tuaj yeem rov ua dua tom qab cua sov, tso cai rau rov siv cov pob khov nab kuab.
2. Polymer Gel-Cov tub yees
Cov pob khov nab kuab niaj hnub no feem ntau siv cov khoom sib xyaw ntawm cov polymers thiab dej, xws li sodium polyacrylate (PAA) lossis polyvinyl cawv (PVA). Cov polymers nqus dej los tsim cov gel thiab maj mam tso lub zog txias los ntawm lub cev adsorbing dej molecules. Cov pob dej khov no feem ntau tsis tas yuav ua kom lub tub yees ua ntej - txias, tuaj yeem siv rau hauv chav sov, thiab muaj kev nyab xeeb, ua rau lawv tsim nyog rau kev khaws zaub mov.
3. Phase Change Materials (PCMs)
Qee qhov siab - cov pob khov khov kawg siv cov khoom hloov pauv hloov pauv, xws li paraffin wax lossis fatty acids (xws li stearic acid). Cov khoom no tau dhau los ua cov khoom ua kua- theem hloov pauv ntawm qhov kub thiab txias (piv txwv li, 5℃~ 18 degree), nqus cov cua sov ntau, yog li tswj tau qhov ruaj khov qis - qhov kub thiab txias ib puag ncig. Qhov zoo ntawm cov ntaub ntawv hloov pauv theem (PCMs) yog kev tswj qhov kub thiab txias thiab rov siv dua.
Cooling Mechanism thiab Preservation Effect
Lub hauv paus ntsiab lus txias ntawm cov pob khov nab kuab feem ntau yog ua raws li cov tshuaj tiv thaiv kab mob endothermic lossis theem hloov cov tshuaj tiv thaiv endothermic:
• Dissolution endothermic cov tshuaj tiv thaiv (xws li ammonium nitrate): Thaum cov ntsev yaj, lawv cuam tshuam cov qauv siv lead ua lattice, siv cov cua sov nyob ib puag ncig thiab ua rau kub poob sai.
• Kev nqus dej ntawm lub cev (piv txwv li, polymer gel): Cov khoom siv polymer nqus dej thiab tsim cov gel, maj mam tso lub zog txias los ntawm dej evaporation lossis adsorption.
• Theem hloov endothermic cov tshuaj tiv thaiv (xws li, paraffin wax): cov khoom siv nqus cua sov thiab hloov mus rau hauv cov kua hauv lub xeev thaum lawv ncav cuag lawv qhov melting point, tswj qhov kub tsis tu ncua.
Hauv cov ntawv thov noj su, cov hnab ntim dej khov feem ntau yog muab cais tawm ntawm cov zaub mov kom tsis txhob muaj kev sib cuag ncaj qha uas tuaj yeem ua rau zaub mov ntub lossis lwj. Lawv lub sijhawm ua kom txias txias yog feem ntau 2-6 teev, nyob ntawm qhov kub thiab txias ntawm lub ntim dej khov.
Kev nyab xeeb thiab Environmental Friendliness
Thaum cov khoom ntim dej khov (piv txwv li, ammonium nitrate) muaj qhov ua kom txias txias, tuaj yeem ua rau tawv nqaij lossis zaub mov khaus. Yog li ntawd, cov khoom siv niaj hnub no feem ntau siv tsis yog - cov tshuaj lom polymers lossis zaub mov- qib PCMs. Cov ice packs rov qab siv tau (xws li sodium acetate lossis PVA gel) muab cov txiaj ntsig zoo ib puag ncig los ntawm kev txo qis kev siv ib zaug - siv cov yas.
Lunchbox ice packs muaj ntau yam tshuaj muaj pes tsawg leeg, suav nrog cov ntsev inorganic, polymer gels, thiab cov ntaub ntawv hloov theem. Lawv cov txheej txheem cua txias feem ntau vam khom rau cov tshuaj tiv thaiv endothermic lossis cov txheej txheem hloov theem. Kev xaiv cov khoom ntim dej khov uas tsim nyog yuav tsum tau xav txog cov kev xav tau ntawm tub yees, kev nyab xeeb, thiab ib puag ncig tus phooj ywg los xyuas kom meej cov khoom noj tshiab thaum lub sij hawm thauj thiab khaws cia. Nyob rau hauv lub neej yav tom ntej, nrog rau kev nce qib hauv cov ntaub ntawv tshawb fawb, kev ua kom zoo dua thiab muaj kev nyab xeeb dua cov ntawv ntim dej khov yuav ua kom zoo dua qub rau kev txuag zaub mov.
