| 摘要 |
<p>A system is disclosed for providing an interconnection between two needle valves such that movement of either needle valve, in opening or closing thereof, is affected or limited by movement of the other valve. The invention is particularly suited to an anesthesia machine wherein separate supplies of oxygen (O2) and nitrous oxide (N2O) are fed to individual needle valves which are then individually adjusted to provide a desired mixture of N2O and O2 for administration to a patient to anesthetize the same. The system herein disclosed interconnects the individual needle valves such that the O2 needle valve may be opened fully without restriction, however, when the N2O valve is open, the interconnection provides that closing of the O2 valve will, at a predetermined point, also correspondingly close the N2O valve, thus preventing the percentage of N2O in the mixed gas from raising above a set value, i.e. one at which sufficient oxygen for a respirable mixture is assured. Similarly, the N2O valve is prevented, through the same interlock system, from being opened beyond a point where the N2 O percentage could exceed such limit. Again, when the N2O valve reaches the predetermined point, further opening of the N2O valve also opens the O2 valve such that the flow can be increased by further opening of the N2O valve but the percentage of N2O and O2 will thereafter remain constant. In addition, the overall system has a further preventative feature where the flow of oxygen cannot be set below a predetermined value so that sufficient oxygen flow to the patient is assured.</p> |
