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All Glass Vacuum Tube

      Surromax solar energy vacuum tube adopts all-glass double tube co-axial structure, made of high borosilicate 3.3 glass, super vacuum which achieves 2×10-3Pa..
     The vacuum tube is similar to a conventional Dewar flask, which consists of two borosilicate glass tubes, with perfect chemical and thermal shock resistance. The outside of the inner tube that is closed at one end and sealed at the other end of the outer tube, is coated with a sputtered solar selective layer. The annular space between the outer tube and inner tube is evacuated that virtually eliminates heat loss caused by conduction and convection.



Techniques & Features :

1. Excellent performance of absorbing, but low heat loss, Especially adapted to sever cold regions,(super heat preservation).

        Surromax successfully introduced the Advanced Solar Selective Coating, which achieves the greater thermal efficiency and better thermal stability innovatively. The solar selective coating absorbs most solar radiation as well as suppresses the thermal emittance loss from the coating. With the help of DC magnetron sputtering technology, the absorptance of 0.94 - 0.96 and emittance of 0.04 - 0.06 has been achieved. The main absorbing wavelength ranges from 0.35μm to 3.0μm

2. Excellent resistance of burst.
   Improved molecule structure of plated selective coating, attributed to DC magnetron sputtering technology, makes the highest of vacuum tube working temperature as high as 500℃, effectively preventing the coating from bursting, aging, discoloring, function attenuating because of long time burn under the sun, prolonging its life span to 15 years.

   Furthermore, the special material plated on tube coating is activated promptly once sun irradiates. The upper surface of semi-cylinder of tube heated by sunshine directly, and the under surface heated by reflected ray at the same time, have different temperatures, so the thermal force propels the water to cycle in the tube rapidly. Consequently, the water circulation in the tube which is made of toughened high borosilicate 3.3 glass balances the temperature and prevents tube from burst.

3.Excellent resistance of corrosion, long life span ( up to 15 years)

Standard PYREX high borosilicate glass with coefficient of linear expansion 3.3×10-6/℃, complies with international ISO1776 acid proof Grade 1, ISO695 alkali proof above Grade 2. It can resist the hailstone with Diameter 25mm, resisting pressure 1MPa.

4.Reducing the fouling on the tube wall, keeping water clean.

Adopts water deionizing equipment HYDRANAUTISS (HAIDENENG) imported from America, the resistivity of deionized water reachs 10 Megohm, keeping the tube surface cleaner and the absorptance higher.

. Specification:

Models

Classic vacuum tube

Triple vacuum tube

  

  

Structure

All glass double tube co-axial structure

Glass material

High borosilicate 3.3 glass

Outer tube diameter and thickness

Ф47±0.7mm/Ф58±0.7mm

Inner tube diameter and thickness

Ф37±0.7mm/Ф47±0.7mm

Tubes length

1500±4mm/1800±4mm

Material of coating

AL/N/AL

Al N/Al N-SS/Cu

Absorptance

0.90~0.94

0.94~0.96

Vacuum

P≤2×10-3pa

P≤2×10-3pa

Transmittance of Outer Tube

0.93

0.93

Stagnation temperature (height)

250~270℃

270~300℃

Heat-loss coefficient

≤0.6w/ m2*℃)

≤0.3w/ m2*℃)

Bearing hailstone ability

hailstone diameterФ25mm

hailstone diameterФ25mm

Pressure-endure ability

1MPa

1MPa

Life span

15 years

15 years

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