| 摘要 |
<p>1,109,660. Gas chromatography. I. HALASZ. 7 Sept., 1965 [8 Sept., 1964], No. 38276/65. Heading B1L. [Also in Divisions F2 and G3] Automatic control of the inlet pressure of a gas chromatography column is effected by means of a valve 3 having member 26 controlled by a membrane 22 which is supported by adjustable spring 19, gas being bled from line 1 through valve 13 and pressure reducing system 7 to counterpressure chamber 6 of valve 3, thereby permitting an exponential pressure rise with time for the carrier gas passing through line 1 and gas chromatography column 5. In Fig. 2 (not shown), the gas is bled from a point in line 1 before valve 3 instead of after and in this case the pressure increase is proportional to the ratio of two hyperbolic tangent functions of time. In Fig. 3 (not shown) the principal column 5 is subjected to a temperature programme-thus affecting the flow resistance of the column. Additional gas is bled from line 1 through subsidiary column 27 under the same conditions as those obtaining in principal column 5. This gas bleed operates valve 28 so that on increase of temperature in the column and hence increase of flow resistance, the pressure in chamber 15 is lowered and valve 28 closed. As a result, less carrier gas from 7 escapes at valve 30, and hence valve 3 is opened so that the pressure of the carrier gas at the column inlet 5a is increased to compensate for the increased resistance of the column 5. The response times of the control circuits of the invention may be lengthened by the addition of side chambers of various volumes.</p> |
