Flow monitoring method and apparatus

• US 4,467,844 A
• Filed: 06/24/1982
• Issued: 08/28/1984
• Est. Priority Date: 06/24/1982
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter Travenol Laboratories Incorporated
• Inventors: Di Gianfilippo, Aleandro, Figler, Alan A.
• Primary Examiner(s): Bell, Jr., Houston S.
• Application Number:
  US06/391,758
• Time in Patent Office: 796 Days
• Field of Search: 141/1, 141/83, 141/9, 141/99-107, 141/237-248, 141/94-96, 141/367, 141/368, 141/351-362, 177/50, 177/1, 177/70, 177/80, 177/121, 177/137, 177/164, 177/210 R, 177/211, 222/39, 222/52, 222/77, 340/606, 340/613, 73/296, 604/65, 604/66, 604/67, 604/DIG. 12, 604/DIG. 13
• US Class Current: 141/1
• CPC Class Codes: G01F 23/20 by measurement of weight, e.g. to determine the level of stored liquefied gas
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2035/00217 involving measurement of weight

Abstract

The present invention provides an economical quick and accurate method and apparatus for transferring and monitoring a preselected amount of fluid from a fluid source container to a receiving container. The method and apparatus monitors the flow rate of the fluid to be transferred by measuring the weight change of the receiving container per unit time.

A weight sensor monitors the weight of the receiving container at various time intervals. The weight information received by the control module at the various time intervals is compared to each other and to predetermined values for the detection of no flow, low flow or high flow conditions.

Claims

1. A fluid transfer and monitoring apparatus for delivering a predetermined amount of fluid from at least one fluid source adapted to contain a fluid, to a fluid receiving container adapted to receive fluid from said fluid source, through motive means operatively adapted to transfer said fluid from said fluid source to said receiving container, the improvement comprising:

means for detecting a first base weight of said fluid receiving container at a first instant of time and a second weight of said fluid receiving container at a second instant of time later than said first instant of time;

means for comparing said first and second weights; and

alarm means responsive to said comparison means for initiating an alarm when said second weight is not greater than said first weight thereby indicating lack of fluid flow from said fluid source to said receiving container.

2. The apparatus of defined in claim 1 including:

sensing means for sensing the operation of said motive means; and

said detecting means initiating detecting said first base weight and said second weight responsive to said sensing means sensing the operation of said motive means.

3. The apparatus as defined in claim 2 wherein said means for detecting includes weight sensing means for sensing the weight of said receiving container.

4. The apparatus as defined in claim 3 wherein said weight sensing means is a load cell.

5. The apparatus as defined in claim 3 wherein said weight sensing means is a strain gauge.

6. The apparatus as defined in claim 3 wherein:

said means for comparing includes further comparing means for comparing said first and second weights against a predetermined weight change; and

said alarm means including low flow indicator means for indicating low flow when said weight change between said first and second weights is less than said predetermined weight change.

7. The apparatus as defined in claim 6 wherein said alarm means further includes high flow indicator means for indicating high flow when said weight change between said first and second weights is greater than said predetermined weight change.

8. The apparatus as defined in claim 7 including delay means for determining said second instant of time later than said first instant of time.

9. The apparatus as defined in claim 3 wherein:

said means for comparing include further comparing means for comparing a correlate of said first and second weights against a correlate of a predetermined weight change; and

said alarm means including low flow indicator means for indicating low flow when said correlate of said weight change between said first and second weights is less than said correlate of said predetermined weight change.

10. The apparatus as defined in claim 9 wherein said alarm means further include high flow indicator means for indicating high flow when said correlate of said weight change between said first and second weights is greater than said correlate of said predetermined weight change.

11. The apparatus as defined in claim 7 wherein:

said motive means is operated at a first operational speed for delivering a portion of said predetermined weight; and

said motive means is operated at a second operational speed, slower than said first operational speed, for delivering a final portion of said predetermined weight.

12. The apparatus as defined in claim 11 wherein said second operational speed delivers small amounts of fluid in pulses for the final portion of said predetermined weight to accurately obtain said predetermined weight.

13. The apparatus as defined in claim 1, 2 or 6 wherein there is provided a plurality of solution sources.

14. A method for precisely monitoring fluid transfer of a predetermined amount from at least one fluid source, to a fluid receiving container, by motive means, comprising:

detecting a first base weight of said receiving container at a first instant of time and detecting a second weight of said receiving container at a second instant of time later than said first instant of time;

comparing said first and second weights; and

activating an alarm when said second weight is not greater than said first weight, thereby indicating lack of fluid flow from said fluid source to said receiving container.

15. The method as defined in claim 14 further including:

delivering said at least one fluid by operating said motive means;

sensing the operation of said motive means; and

initiating detection of said first base weight and said second weight responsive to the sensing of the operation of said motive means.

16. The method as defined in claim 15 wherein detecting said first and second weights is accomplished by a load cell.

17. The method as defined in claim 15 wherein detecting said first and second weights is accomplished by a strain gauge.

18. The method as defined in claim 15 including:

comparing said first and second weights against a predetermined weight change; and

activating an alarm for a low flow condition when said weight change between said first and second weights is less than said predetermined weight change.

19. The method as defined in claim 18 further including activating an alarm for a high flow condition when said weight change between said first and second weights is greater than said predetermined weight change.

20. The method as defined in claim 17 including:

comparing a correlate of said first and second weights against a correlate of a predetermined weight change; and

activating an alarm for a low flow condition when said correlate of said weight change between said first and second weights is less than said correlate of said predetermined weight change.

21. The method as defined in claim 20 further including activating an alarm for a high flow condition when said correlate of said weight change between said first and second weights is greater than said correlate of said predetermined weight change.

22. The method as defined in claim 19 further including:

operating said motive means at a first operational speed for delivering a portion of said predetermined weight; and

operating said motive means at a second operational speed, slower than said first operational speed, for delivering a final portion of said predetermined weight.

23. The method as defined in claim 22 wherein operating said motive means at said second operational speed includes delivering small amounts of said fluid in pulses for the final portion of said predetermined weight to accurately obtain said predetermined weight.

24. The method as defined in claim 14, 15, 19 or 23 including transferring fluids to said receiving container from a plurality of fluid sources.