[Medium glass] Flat glass is generally divided into tempered glass, semi-tempered glass and annealed glass according to the difference of surface compressive stress. According to the American ASTMC1048-1997b standard, the surface compressive stress range of various glasses is: tempered glass >69MPa (10,000psi), semi-tempered glass: 24MPa (3500psi) ~ 52MPa (7500psi). China's "tempered glass for curtain wall" The national standard for semi-tempered glass also has clear requirements for stress. The semi-tempered glass is 24-60 MPa, and the tempered glass is 90 MPa or more. (1) Tempered glass The traditional method of inspecting tempered glass is the impact test. GB9963 and GB9656 stipulate that the number of fragments in the range of 50mm'50mm must be greater than 40. The test shows that there is a good correspondence between the surface stress value and the number of fragments in the stress range of tempered glass. The surface stress value corresponding to the number of 40 fragments is about 82 MPa. The homogenized tempered glass should be used in high-rise buildings. . (2) Heat reinforced glass Heat-enhanced glass is often referred to as "semi-tempered glass" in China. It is very common in construction and has good wind pressure resistance. Such glass, after being destroyed by natural disasters, tends to stay in the window frame without falling, while at the same time ensuring that it does not blew. ASTM stipulates that the stress range of the heat-strengthened glass is 24-52 MPa, and the stress of the tempered glass must be greater than 69 MPa. Glass with a stress in the range of 51-69 MPa is a waste product, and it cannot be used as tempered glass or as a heat-strengthened glass. (3) Tempered safety glass A lot of experience has shown that when tempered glass is used in safety glass applications, its surface stress value is usually greater than 105 MPa. A common example is automotive glass. If the stress is less than 105 MPa, although the number of fragments can still meet the relevant standards, the glass strength is slightly insufficient. (4) Hot bending glass Hot-bending glass is an annealed glass that requires as little internal stress as possible to ensure that the glass does not break due to excessive uneven stress. The stress in the bending part is concentrated, and the surface stress is about 15 MPa, which is easy to cause glass cracking. The surface stress should be reduced to below 7 MPa, which basically solves the problem of cracking at the corner.
What material is a HEPA filter?
HEPA filter: HEPA (High Efficiency Particulate Air Filter) filter, namely high-efficiency air purifier, is a multi-layer purification technology that can filter more than 99.97% of dust particles with a particle size exceeding 0.3 μm. HEPA filters have the characteristics of good filtering effect, good sealing performance and long service life, and are widely used in semiconductor manufacturing factories, liquid crystal electronics factories, modular clean rooms and other occasions requiring ultra-high cleanliness.
HEPA filter media is a kind of synthetic fiber material, which is made of high-performance, high-strength fibers. At the same time, advanced production technology is used to ensure its highly deepened dust holding capacity and ideal low-resistance performance. HEPA filter media compared with other filter materials, high-efficiency filter cotton has higher filtration efficiency and better performance. High-efficiency filter media has its own special structure, which can not only effectively accommodate more dust, but also effectively improve the efficiency of filtration.
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