And because the national standard vacuum tube is of high borosilicate glass 3.3 to soften; high borosilicate glass 3.3 to about 800 degrees high temperature to soften the coating from the mouth of that film. In high temperature, not easy to fall off, long service life. The three is to look at the vacuum tube transparency check to see whether the tube is bright, can see at a glance the coating layer, the vacuum tube has no similar fog feeling should be between the outer wall and the coating layer. The four is to look at the edge of the silver mirror layer at the bottom of the vacuum tube is not a burr burr phenomenon. The vacuum tube shows its high vacuum degree, good heat preservation performance round edge. Qi, which indicates that the vacuum degree is low, poor thermal insulation properties. The five is listening to the murmur, close to the vacuum tube with a nozzle to noise ear, if the noise is strong, that the vacuum tube is higher.
The vacuum tube of.1.8m is about 2.2Kg; the vacuum tube of 1.92m is about 2.4Kg; the vacuum tube of 2.1m is about two 2.6Kg., and the distance between the coating layer and the nozzle is far and near,
Quality inspection, vacuum solar collector with the naked eye, it is a vacuum tube vacuum tube produced by weight, will use some high borosilicate glass 3.3 according to the national standard
