초록 ▼

An apparatus for separating and collecting plasma from whole blood includes a volume monitoring system which provides a continuous display of the volume of plasma collected. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma

An apparatus for separating and collecting plasma from whole blood includes a volume monitoring system which provides a continuous display of the volume of plasma collected. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a difference signal. If the difference is determined to be positive and less than a predetermined maximum collection rate so as to constitute a valid collection increment, the difference is cumulatively added to previous collection increments in a cumulative display counter to provide a collected volume display, and the frequency of the present measurement interval is taken as a frequency of the preceding measurement interval for the next comparison. If the difference is negative, and therefore not a valid collection increment, then no increment is accumulated. If the difference exceeds the predetermined maximum collection rate, and is therefore not a valid collection increment, then no increment is accumulated and the frequency of the preceding measurement interval is not updated. Since the display counter is advanced only for valid collection increments, it provides a display of collected plasma volume, without regard to tare weight changes and physical disturbances to the collection bag.

대표청구항 ▼

In a collection apparatus for collecting a fluid in a collection container, wherein the fluid has a predetermined range of collection rates, a collection monitoring system comprises, in combination: weight responsive means including an electrical transducer in supporting relationship to said contain

In a collection apparatus for collecting a fluid in a collection container, wherein the fluid has a predetermined range of collection rates, a collection monitoring system comprises, in combination: weight responsive means including an electrical transducer in supporting relationship to said container for providing an output signal indicative of the weight of the collection container and the collected fluid container therein; comparison means for repetitively comparing successive output signals to develop difference signals indicative of changes in weight of the collection container over successive measurement intervals; and incrementing means responsive only to difference signals representing collection rates within the range of collection rates for producing collection signals indicative of incremental units of fluid volume added to the collection container.