Three Layer Evacuated Tubes

Evacuated glass tube Models: 58×1800 Structure: Three Target Outer tube diameter: 58±0.7mm Inner tube diameter: 47±0.7mm Outer Tube thickness: 1.6±0.15mm Inner tube thickness: 1.6±0.15mm Tubes length: 1800±10mm Material of coating: Copper, Aluminum, Stainless Steel coating: Three Targets Coating Absorptance :≥0.92 Emittance: ≤0.06 Vacuum: less than 5.2×10-4Pa Transmittance of Outer Tube :0.92 Stagnation temperature (height): 270~300℃ Heat-loss coefficient: less than 0.5 w (m2*℃) Bearing hailstone ability: 30mm steel ball from 450mm