| 摘要 |
<p>Process for controlling the flow of a fluid through a valve having a given section and a movable valve member, in which the pressures of the fluid which are upstream Pupstream and downstream Pdownstream of the valve and the position d of the valve member are measured, then the real flow Qreal of the fluid is calculated and compared with a set value Q0, the difference signal Qreal-Q0 commanding the displacement of the valve member in the desired direction, said process comprising effecting the real flow calculation by measuring the ratio R=Pupstream/Pdownstream which is compared with a predetermined value R and calculating the product Qsonic=kxPupstreamxd so that when R>R0, the product Qsonic is directly compared with a set value Q0, the difference signal Qsonic-Q0 commanding the displacement of the valve member in the desired direction whereas, when R<R0, the ratio R is converted into a digital signal whose value corresponds to the address of a memory whose content is converted into an analog correction signal which, after multiplication by Qsonic, represents a value proportional to the flow Qsubsonic of the fluid at the subsonic rate, this value Qsubsonic being then compared with the set value Q0, the signal Qsubsonic-Q0 commanding the displacement of the valve member in the desired direction.</p> |
