| 摘要 |
For testing the tightness of the gas withdrawal system of a gas analysis device, the gas withdrawal system is sealed, the measuring gas pump is switched on for a period which is safely sufficient to achieve the maximum underpressure. During this time, a flow meter measures the flow. The pump is then switched off and is switched on again after a predetermined time. In the event of a leak, the gas which has penetrated into the withdrawal system is conveyed so that the flow meter determines a flow. By means of comparing the amplitudes of the two flow meter signals it can be established whether and to what magnitude a leak is present. The invention is applied in vehicle exhaust gas measuring devices. <IMAGE> |
