Solar energy Glass Tube

Main specification: Diameter:：￠37、￠47、￠58、￠70.
Suitable for any kinds of routine tube that can gather the solar energy, and its characteristics are: the coefficient of expansion is small, it is capable to bear the difference in temperature so, the capability is very good.
Detailed Product Description
1)Main composition:
a)Sio2：80±0.5%
b)B2O3：13±0.2%
c)Al2O3：2.4±0.2%
d)Na2O（+K2O）：4.3±0.2%
2)Chemical properties:
a)Coefficent of mean linar thermal expansion (20/300℃):3.3±0.1(10-6K-1)
b)Transformation temperature:525±15℃
c)Working point：1.260±20℃
d)Softening point：820±10℃
e)Density at 20℃：2.23g/cm2
f)Hydrolytic resistance at 98℃：ISO719-HGB1
g)Hydrolytic resistance at 121℃：ISO720-HGA1
h)Acid resistance class：ISO1776-1
i)Alkali resistance class：ISO695-A2