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Borosilicate glass

Update:2014-11-27 15:11:22      Click:
  • Brand:   YAOGUO SOLAR
  • Model:   58*1800
  • Online ordering
Product introduction

The solar transmittance ratio (τ) of glass tube is not less than 0.89 in the new national standard. This is physical-chemical performance index for borosilicate glass 3.3.   
The average thermal expansion coefficient α (20℃~300℃)of borosilicate glass 3.3 equals(3.3±0.1)×10-6K-1, we usually call it borosilicate glass 3.3, "AM 1.5" is namely air mass 1.5.
    All the SVT manufacturers will say that the raw material they use is "borosilicate glass 3.3", but if the material is not the "borosilicate glass 3.3" or the material contains too much other element (such as Fe), the color of their tubes will wear other colors (e.g. green), The solar transmittance ratio of tubes made from impure "borosilicate glass 3.3" will be much lower than 0.89, therefore, the performance of SVT will be impacted seriously.
A. refined quartz sand
a. component: SiO2≥99.3%, Fe2O3≤0.03% 
b. granularity: 60 mesh passing rate=100%, 60-140 mesh passing rate ≤80%, 200 mesh passing rate≤5%.
c. moisture≤0.5%
B. borax
a. component: B2O3≥47%,    Na2O≥21%   , Fe2O3≤0.005%                   
C. boric cid
a. component: B2O3≥56%,       Fe2O3≤0.01%,
1 Specifications and Tolerances            Unit: mm

2. Material
2.1. Tube should be made from borosilicate glass 3.3
2.2. After being processed, the blackening of stripes are not allowed to appear in processing position.
3. physical-chemical performance
3.1. The average thermal expansion coefficient
а(20Co—300C0)=(3.3±0.1)*10-6K-1
3.2. Density
ρ(20C0)=2.23±0.02g/cm3
3.3. Internal stress
A birefringent optical path difference≤180 nm cm-1
3.4. Hydrolytic resistance
3.4.1. hydrolytic resistance grade Ⅰ at 98 C0.
3.4.2. hydrolytic resistance grade Ⅰ at 121 C0.
4. Appearance requirements.
4.1. Asbestos moulage, gloves moulage, rust moulage, oil moulage and offset printing should not appear on the surface of tubes
4.2. Recrystallization is not allowed
4.3. Air line
4.3.1. The width of air line is not allowed to be greater than 0.5 mm, air lines of width 0.5 mm or above are not allowed to appear in the range 150 mm to both ends.
4.3.2. outer tube: air lines of 40 mm long or above do not allow to exist, air lines of 20-40 mm long are not allow to exist more than two on the entire tube. Air line of 5-20 mm does not allow existing more than two in the range 200 mm in tube length direction; no more than five below length of 5 mm.
4.3.3. Inner tube: the number of air lines of 20-50 mm long does not allow to exceed 2 on the entire tube. air line of 5-20 mm does not allow to exist more than 2 in the range 200 mm in tube length direction ; no more than 10 below length of 5 mm.
4.3.4. knot: knots Φ≥2 mm are not allowed to exist, knotsΦ<2 mm are not allowed to exceed 2 in the range 200 mm in tube length direction
4.3.5. stone: stones of Φ≥1 mm are not allowed to exist. stonesΦ0.5-1 mm are not allowed to exceed 1 on the entire tube, stonesΦ<0.5 are not allowed to exceed 1 in the range 200 mm in tube length direction.
4.3.6 Straight line: The serious straight line is not allowed, if necessary, physical standard sample can be sealed.
4.3.7. Scratch: slight scratch is allowed unless the length exceed 100 mm, the cumulative length exceed 200 mm.
   Borax, boric acid purchased by our company are high-quality raw materials imported from Turkey. Refined quality quartz sand is purchased from Anhui Fengyang. Strictly control the quality of procurement, each batch of raw material has the original documents to be found. We promise customers do the sampling and testing of raw materials at any time. So the borosilicate glass we produce are better than the national quality inspection standards.

 

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