glass vacuum tube

with 3.3 lineary expansion,good waterproof and acid-resistant,for solar collector,chemical pipe,gifts and crafts making purpose
Specification:
Structure
All-glass double-tube co-axial structure
Glass material
High borosilicate 3.3 glass
External pipe diameter and thickness
dia.=47±0.7mm &=1.6mm dia.=58±0.7mm &=1.6mm
dia.=70±0.7mm &=2.0mm
Internal pipe diameter and thickness
dia.=37±0.7mm &=1.6mm dia.=47±0.7mm &=1.6mm
dia.=58±0.7mm &=1.6mm
Pipe length
1500mm 1600mm 1800mm1900mm 2100mm
Absorptive coating property
Structure
AL/AL-ALN(H)/AL-ALN(L)/ALN
Sediment method
Single target magnetron sputtering plating
Specific absorption
as=0.88~0.92(AM1.5)
Emission ratio
0.05~0.075(80°C±5°C)
Vacuum tightness
P≤5.0×10-³Pa
Idle sunning property parameters
Y= 220 ~ 260m²°C/KW
Average heat loss coefficient
Ult=0.86W/m
2