Lundgren D A, Gunderson T C
Am Ind Hyg Assoc J. 1975 Dec;36(12):866-72. doi: 10.1080/0002889758507358.
It was experimentally demonstrated that Gelman Type A and "Microquartz" filters are efficient collectors of nonvolatile particles at high temperatures. Submicron particles penetrated more than large particles, and most at the highest filtration velocity tested of 51 cm/sec. In all tests, however, aerosol penetration was never more than about 0.10%. Nonvolatile particles penetrated less with increasing temperature filter loading. Particles with vaporization points below the sampling temperature, including H2SO4, can vaporize, pass through the glass fiber filters, and then recondense when cooled below their dew points. Therefore, the definition of "particulate matter" must be based upon a prescribed temperature. Hot stack gases, sampled at different filter temperatures, should not necessarily be comparable. Particulate emission standards must involve a suitable reference temperature to allow proper enforcement. Filtration efficiencies calculated by theoretical equations change dramatically with small changes in assumed average filter fiber diameter and/or particle size (or size distribution) used in the calculations. Pinholes not visible to the naked eye do not appear to effect penetration of glass fiber filters enough to significantly alter stack sampling results. Effect of temperature on filtration of non-volatile particles simply resulted in an increasing collection of submicron particles with increasing temperature. The main problems encountered at elevated temperatures were vaporization of volatile particles and mechanical leakage of the filter holder.
实验证明，盖尔曼A型过滤器和“微石英”过滤器在高温下是高效的非挥发性颗粒收集器。亚微米颗粒比大颗粒穿透性更强，在测试的最高过滤速度51厘米/秒时穿透性最强。然而，在所有测试中，气溶胶穿透率从未超过约0.10%。随着温度和过滤器负载增加，非挥发性颗粒的穿透性降低。汽化点低于采样温度的颗粒，包括硫酸，会汽化，穿过玻璃纤维过滤器，然后在冷却至露点以下时重新凝结。因此，“颗粒物”的定义必须基于规定的温度。在不同过滤器温度下采样的热烟囱气体不一定具有可比性。颗粒物排放标准必须涉及合适的参考温度，以便正确执行。通过理论方程计算的过滤效率会随着计算中假设的平均过滤器纤维直径和/或颗粒尺寸（或尺寸分布）的微小变化而显著变化。肉眼不可见的针孔似乎对玻璃纤维过滤器的穿透性影响不足以显著改变烟囱采样结果。温度对非挥发性颗粒过滤的影响仅仅是随着温度升高，亚微米颗粒的收集量增加。在高温下遇到的主要问题是挥发性颗粒的汽化和过滤器支架的机械泄漏。
