| 摘要 |
<p>The device does not depend on a connection to the cylinder, but provides a calculated value for the quantity of gas remaining on the basis of measured parameters. The portable device provides an independent indication of the amount of oxygen remaining in a gas cylinder, whilst the external pressure is constant. It comprises a support (1) carrying at least one table of values, addressed by a cursor as a function of the pressure within the gas cylinder, and a fixed flow rate. A display window (3) shows directly the quantity of oxygen remaining within the cylinder as a function of these two values. The device may operate by use of a slide-rule type device whereby the cursor points to specific figures within a table. Alternatively the device may be an electronic processor with a memory, in which case the pressure and flow rate parameters may be entered via a keypad, and the resulting quantity of oxygen displayed on an electronic display panel.</p> |
