Approximately what inches-of-mercury vacuum reading corresponds to the 25 mm Hg absolute recovery level for low-pressure appliances?

解析

25 mm Hg absolute is a deep vacuum equal to roughly 29 inches of mercury vacuum on a compound gauge, since atmospheric pressure is about 760 mm Hg, or 29.9 inches Hg. That is far deeper than the 0 to 15 inches Hg levels that 40 CFR §82.156 Table 1 sets for very-high-, high- and medium-pressure appliances. It reflects how completely a low-pressure chiller must be emptied.