Patent ID: 7823587

Claim:
A process for monitoring the valves of an anesthetic dispenser with a safety valve connected in series with a dispensing valve for dispensing the anesthetic in the form a vapor, as well as with a saturated vapor branch having a downstream dispensing gap and a mixed gas branch having a fixed bypass resistance, the process comprising the steps of: (a) providing a mixed gas branch connected to said saturated vapor branch via a dispensing gap; (b) providing a gas inlet; (c) providing a gas outlet; (d) providing a first bypass line and a second bypass line; (e) providing a ventilation duct which is open toward the environment, said ventilation duct being connected to said second bypass line; (f) providing a switching means for connecting said gas inlet directly with said gas outlet via said first bypass line and connecting said mixed gas branch and said saturated vapor branch to said ventilation duct via said second bypass line in a gas tightness check position and for connecting said gas inlet to said gas outlet via said mixed gas branch in a non-gas tightness check position; (g) opening the dispensing valve for an equalization time; (h) closing the safety valve and the dispensing valve and measuring the differential pressure between the saturated vapor branch and the mixed gas branch by means of a differential pressure sensor; (i) opening the safety valve or the dispensing valve and measuring the differential pressure between the saturated vapor branch and the mixed gas branch by means of the differential pressure sensor; and (j) closing the opened safety valve or the opened dispensing valve and comparing the difference between the differential pressures measured in steps (h) and (i) with a preset limit value, so that the valve not opened in step (i) is considered to be tight when the difference is below said preset limit value, wherein said steps (g), (h), (i) and (j) are performed when said switching means is in said gas tightness check position.