Remote electrical monitoring of gas activated blood pumps
US3974825A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 1, 1975 |
| Grant date | Aug 17, 1976 |
| Priority date | — |
| Expiry date | Oct 1, 1995 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M2205/3334
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An electrical capacitance measurement system for monitoring at a distance the instantaneous blood volume within the body of an air or gas activated blood pump. Electrical capacitance changes within the pneumatic blood pump frequency modulates an oscillator, and the extraneous capacitances encountered are incorporated as electrical, integral components in oscillator operation. An inductor, placed within or in close proximity to the pump, and the relatively small electrical capacitance within the pump form an oscillator tank which primarily determines oscillator frequency. By thus creating a tank at the site of measurement, active and other oscillator components can be placed at a distance from the pump, and undesirable cable capacitances can conveniently be incorporated as participating feedback capacitors. Preferably, an electrically protective shield is attached to the outside of the pump which electrically shields the pump and which provides a capacitance larger than the sensing capacitance to provide a linear relationship between the sensing capacitance and the sensor output. The Clapp oscillator principle has been employed as it permits the separate location of the sensing, fre…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.