Stepping motor control procedure for achieving variable rate, quasi-continuous fluid infusion
US4474309A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 22, 1981 |
| Grant date | Oct 2, 1984 |
| Priority date | — |
| Expiry date | Oct 22, 2001 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M2205/12
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A control procedure for governing the incremental step operation of a pump stepping motor (74) employed in conjunction with a parenteral fluid metering device (2) is disclosed. The control procedure enables fluid to be pumped from the metering device (2) in non-pulsatile, essentially continuous fashion by suitably adjusting the stepping motor speed to compensate for the interruption of fluid flow which occurs during the refill phase (P.sub.R) of each pumping cycle (C). Adjustment of the stepping motor speed also compensates for non-linearities otherwise introduced into the fluid flow as a result of the camming mechanism (76,78) utilized to convert rotary stepping motor movement into rectilinear pumping movement. Operating power for the stepping motor is conserved by drawing relatively large amounts of current through the stepping motor (74) only at the outset of each incremental step while drawing relatively smaller amounts of current through the stepping motor (74) during the remaining interval between incremental steps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.