| 摘要 |
<p>PURPOSE: To create a low-concn. mixture of an exact concn. by dividing a high purity diluent gas to first and second portions, mixing the first portion and a high-concn. standard gas to form a middle-concn. gaseous mixture and diluting the streams dividing the same by the second portion. CONSTITUTION: After the pressure of gaseous raw material 1 is controlled, the gaseous raw material is refined to form the high purity diluent gas. This high purity diluent gas is divided to the first portion 16 and the second portion 17. The flow rate of the at least one high-concn. standard gas 6 is controlled and the first portion 16 and the standard gas 6 are mixed to form the middle- concn. gaseous mixture 8. This gaseous mixture 8 is divided to the first stream 9 and the second stream 10. The first stream 9 is diluted by the second portion 17 to form the low-concn. gaseous mixture 22. The pressure of the second stream 10 is controlled and the pressure of the low-concn. gaseous mixture 22 is controlled. Consequently, the low-concn. mixture having a desired exact concn. of one or several species in the gaseous raw material is produced.</p> |
