Fluid flow meter

Abstract

A fluid flow meter comprising a housing having a pair of fluid ports and defining therebetween a fluid flow path; a flexible membrane defining a pair of opposing faces and being mounted in the fluid flow path such that the pair of faces simultaneously define with the housing fluid impermeable seals at at least two different locations along the flow path, the membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume; apparatus for generating electrical signals corresponding to flexure of the membrane; and monitoring apparatus for receiving the electrical signals and thereby determining a fluid flow rate along the flow path.

I claim: 
     
       1. A fluid flow meter comprising: a housing having a pair of fluid ports and defining therebetween a fluid flow path:   a flexible membrane defining a pair of opposing faces and being mounted in said fluid flow path such that said pair of faces simultaneously define with said housing fluid impermeable seals at at least two different locations along said flow path, said membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume varying as a function of flow rate;   means for generating electrical signals corresponding to flexure of said membrane; and   monitoring means for receiving the electrical signals over a measured period of time, determining the rate of said electrical signals, determining the volume of said quanta based upon said electrical signal rate, and thereby determining a fluid flow rate along said flow path.   
     
     
       2. A fluid flow meter according to claim 1, and wherein said membrane further defines a pair of edges lying in respective planes substantially parallel to the direction of fluid flow and said fluid flow path has a uniform cross-sectional configuration along at least part of its length, said fluid impermeable seals being defined therealong. 
     
     
       3. A fluid meter according to claim 2, and wherein said part of said flow path length having a uniform cross-sectional configuration has a rectangular cross-sectional configuration and is defined by first and second pairs of parallel walls, said membrane being disposed therebetween such that said respective planes in which said membrane edges lie are aligned substantially parallel to said first pair of walls. 
     
     
       4. A fluid flow meter according to claim 3, and wherein said fluid impermeable seals are defined at at least three locations along said flow path. 
     
     
       5. A fluid flow meter according to claim 4, and wherein said membrane edges are spaced from said first pair of walls by substantially a fluid boundary layer thickness. 
     
     
       6. A fluid flow meter according to claim 5, and wherein said membrane has a rectangular configuration and is oriented such that its longitudinal axis lies parallel to the direction of flow. 
     
     
       7. A fluid flow meter according to claim 6, and wherein said membrane is operative to permit passage of discrete quanta of fluid by flexure in wavelike fashion, said membrane having first and second ends mounted in said housing, said flow meter further including at least one guide member adjacent to at least one of said ends for assisting the wavelike flexure of said membrane. 
     
     
       8. A fluid flow meter according to claim 7, and wherein said membrane first and second ends are mounted for partial rotation about respective first and second axes parallel to said second pair of walls and passing through said first pair of walls. 
     
     
       9. A fluid flow meter according to claim 8, and wherein said housing is configured to permit deposition of debris from said fluid at a location upstream of said membrane but downstream of an adjacent fluid port. 
     
     
       10. A fluid flow meter according to claim 9, and wherein each of said walls defines an inward-facing surface having antistatic and hydrophobic properties. 
     
     
       11. A fluid flow meter according to claim 7, wherein said flow meter includes a pair of guide block having rounded inner faces in opposing relationship adjacent at least one of said ends. 
     
     
       12. A fluid flow meter according to claim 7, wherein said at least one guide member comprises an elongated member. 
     
     
       13. A fluid flow meter according to claim 42, wherein each of said guide blocks further .[.comprise.]. .Iadd.comprises .Iaddend.a fluid permeable extension mounted to said guide block inner face. 
     
     
       14. A fluid flow meter according to claim 1, and wherein said membrane comprises a layer of piezoelectric material. 
     
     
       15. A fluid flow meter according to claim .[.11.]. .Iadd.14.Iaddend., and wherein said membrane also comprises a pair of metallized layers surrounding said layer of piezoelectric material. 
     
     
       16. A fluid flow meter according to claim 15, and wherein said piezoelectric material is polyvinylidene fluoride. 
     
     
       17. A fluid flow meter according to claim 15, and wherein said metallized layer comprises discrete metallized portions provided at predetermined discrete locations on said membrane. 
     
     
       18. A fluid flow meter according to claim 1, and wherein said means for generating comprises first and second electrical contacts mounted, respectively, onto a surface of said membrane and in association with said monitoring means and such that an electrical signal is generated upon release of a single quantum of fluid. 
     
     
       19. A fluid flow meter according to claim 1, and wherein said flexible membrane comprises magnetized material and said means for generating comprises a magnetic head operative to generate and electrical signal upon sensing proximity of said membrane thereto. 
     
     
       20. A fluid flow meter according to claim 1, and wherein said monitoring means includes means for identifying electrical signals generated by flexure of said membrane upon release therefrom of a single quantum of fluid. 
     
     
       21. A fluid flow meter according to claim 1, and wherein there is also provided means for sensing the temperature of said fluid. 
     
     
       22. A fluid flow meter according to claim 21, and wherein said monitoring means also includes means responsive to said temperature sensing means for providing an alarm indication when the temperature of the fluid reaches at least a predetermined temperature. 
     
     
       23. A fluid flow meter according to claim 1, and wherein there is also provided means for sensing the pressure of the fluid. 
     
     
       24. A fluid flow meter according to claim 23, and wherein said monitoring means also includes means responsive to said pressure sensing means for providing an alarm indication when the pressure of the fluid reaches at least a predetermined pressure. 
     
     
       25. A fluid flow meter according to claim 1, and also including remote data collection means and wherein said monitoring means also includes means for providing fluid flow data thereto. 
     
     
       26. A fluid flow meter according to claim 31, wherein said remote data collection means comprises automatic dialing means operatively connected to a telephone communications systems. 
     
     
       27. A fluid flow meter comprising: a housing having a pair of fluid ports and defining therebetween a fluid flow path;   a flexible membrane having varying thicknesses along at least part of its length defining a pair of opposing faces and being mounted in said fluid flow path such that said pair of faces simultaneously define with said housing fluid impermeable seals at at least two different locations along said flow path, said membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume;   means for generating electrical signals corresponding to flexure of said membrane; and   monitoring means for receiving the electrical signals and thereby determining a fluid flow rate along said flow path.   
     
     
       28. A fluid flow meter comprising: a housing having a pair of fluid ports and defining therebetween a fluid flow path;   a flexible membrane defining a pair of opposing faces and being mounted in said fluid flow path such that said pair of faces simultaneously define with said housing fluid impermeable seals at at least three different locations along said flow path, said membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume;   said membrane further defining a pair of edges lying in respective planes substantially parallel to the direction of fluid flow and said fluid flow path having a uniform cross-sectional configuration along at least part of its length, said fluid impermeable seals being defined therealong;   said part of said flow path length having a uniform cross-sectional configuration having a rectangular cross-sectional configuration defined by first and second pairs of parallel walls, said membrane being disposed therebetween such that said respective planes in which said membrane edges lie are aligned substantially parallel to said first pair of walls;   said membrane edges being spaced from said first pair of walls by substantially a fluid boundary layer thickness; and   said first pair of walls being made from a flexible material;   means for generating electrical signals corresponding to flexure of said membrane; and   monitoring means for receiving the electrical signals and thereby determining a fluid flow rate along said flow path.   
     
     
       29. A fluid flow membrane to claim 28, wherein each of said pair of side walls defines a space adjacent to a portion of said membrane. 
     
     
       30. A fluid flow meter according to claim 28, wherein said flexible material is a flexible elastomer. 
     
     
       31. A fluid flow meter comprising: a housing having a pair of fluid ports and defining therebetween a fluid flow path;   a flexible membrane defining a pair of opposing faces and being mounted in said fluid flow path such that said pair of faces simultaneously define with said housing fluid impermeable seals at at least three different locations along said flow path, said membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume;   said membrane further defining a pair of edges lying in respective planes substantially parallel to the direction of fluid flow and said fluid flow path has a uniform cross-sectional configuration along at least part of its length, said fluid impermeable seals being defined therealong;   said part of said flow path length having a uniform cross-sectional configuration having a rectangular cross-sectional configuration and being defined by first and second pairs of parallel walls, said membrane being disposed therebetween such that said respective planes in which said membrane edges lie are aligned substantially parallel to said first pair of walls;   said membrane edges being spaced from said first pair of walls by substantially a fluid boundary layer thickness;   each of said first pair of walls comprising a roughened surface;   means for generating electrical signals corresponding to flexure of said membrane; and   monitoring means for receiving the electrical signals and thereby determining a fluid flow rate along said flow path.   
     
     
       32. A fluid flow meter comprising: a housing having a pair of fluid ports and defining therebetween a fluid flow path;   a flexible membrane defining a pair of opposing faces and being mounted in said fluid flow path such that said pair of faces simultaneously define with said housing fluid impermeable seals at at least two different locations along said flow path, said membrane being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume;   means for generating electrical signals corresponding to flexure of said membrane; and   monitoring means for receiving the electrical signals and thereby determining a fluid flow rate along said flow path;   said monitoring means including means for identifying electrical signals generated by flexure of said membrane upon release therefrom of a single quantum of fluid;   said monitoring means also including means for determining the rate of fluid flow based upon electrical signals received over a measured period of time; and   said monitoring means also comprising means for storing a predetermined value of volume for a single quantum of fluid flow, means for calculating a fluid flow rate corresponding to a number of electrical signals received over a measured period of time, means for comparing said predetermined value for said single quantum with a reference value of volume based upon the flow delivery characteristics of said meter at said first rate of flow, means for adjusting said predetermined value to said reference value of volume based upon the flow delivery characteristics of said matter, and means for repeatedly adjusting the predetermined value of volume of a single quantum of fluid so as to obtain an increasingly more accurate value of flow.   
     
     
       33. A fluid flow meter according to claim 32, and wherein said monitoring means also includes means for calculating an adjusted quantum volume according to the sensed temperature of the fluid. 
     
     
       34. A fluid flow meter according to claim 32, and wherein said monitoring means also includes means for calculating an adjusted quantum volume according to the sensed pressure of the fluid. .Iadd. 
     
     
       35.  A fluid flow meter as in claim 1, wherein the membrane further comprises means for reinforcing against fatigue stresses. .Iaddend..Iadd.36. A fluid flow meter as in claim 35, wherein the membrane has an end for mounting in the housing and the reinforcing means comprises a thickened cross-section at the end of the membrane. .Iaddend..Iadd.37. A fluid flow meter as in claim 1, wherein the membrane has a pair of edges lying in respective planes substantially parallel to the direction of fluid flow, wherein the fluid flow path is defined by at least one pair of walls, and wherein the pair of edges of the membranes are spaced from the pair of walls respectively by substantially a fluid boundary layer thickness. .Iaddend..Iadd.38. A fluid flow meter as in claim 37, wherein each of the pair of walls comprises a roughened surface. .Iaddend..Iadd.39. A fluid flow meter as in claim 1, wherein the membrane has first and second ends mounted in the housing and wherein the flow meter includes a pair of guide blocks having rounded inner faces in opposing relationship adjacent at least one of the ends. .Iaddend..Iadd.40. A fluid flow meter as in claim 39, wherein each of the guide blocks further comprises an extension mounted to each of the guide block inner faces, said extension allowing fluid to pass therethrough. 
     
     
        .Iaddend..Iadd.41.  A fluid flow meter as in claim 27, wherein the membrane has a thickened end for reinforcing against fatigue stresses. .Iaddend..Iadd.42. A fluid flow meter as in claim 27, wherein the monitor means further comprises means for compensating for non-uniformity of the volume of the quanta of fluid at different flow rates. .Iaddend..Iadd.43. A fluid flow meter as in claim 42, wherein the compensating means comprises means for storing respective values of the volume of the quanta of fluid at different flow rates. .Iaddend..Iadd.44. A fluid flow meter as in claim 27, wherein the membrane having first and second ends mounted in the housing and wherein the flow meter includes a pair of guide blocks having rounded inner faces in opposing relationship adjacent at least one of the ends. .Iaddend..Iadd.45. A fluid flow meter as in claim 44, wherein each of the guide blocks further comprises an extension mounted to each of the guide block inner faces, said extension allowing fluid to pass therethrough. .Iaddend..Iadd.46. A fluid flow meter as in claim 28, wherein the membrane further has means for reinforcing against fatigue 
     
     
        stresses. .Iaddend..Iadd.47.  A fluid flow meter as in claim 46, wherein the reinforcing means comprises a thickened cross-section at an end of the membrane for mounting to the housing. .Iaddend..Iadd.48. A fluid flow meter as in claim 28, wherein the monitor means further comprises means for adjusting the determined fluid flow rate to offset changes of the volume of the quanta of fluid at different flow rates. .Iaddend..Iadd.49. A fluid flow meter as in claim 48, wherein the adjusting means comprises means for storing respective values of the volume of quanta of fluid at different flow rates. .Iaddend..Iadd.50. A fluid flow meter as in claim 28, wherein the membrane has first and second ends mounted in the housing and wherein the flow meter includes a pair of guide blocks having rounded inner faces in opposing relationship adjacent at least one of the ends. .Iaddend..Iadd.51. A fluid flow meter as in claim 50, wherein each of the guide blocks further comprises an extension mounted to each of the guide block inner faces, said extension allowing fluid to pass therethrough. 
     
     
        .Iaddend..Iadd.52.  A fluid flow meter as in claim 31, wherein the membrane has first and second ends mounted in the housing and wherein the flow meter includes a pair of guide blocks having rounded inner faces in opposing relationship adjacent at least one of the ends. .Iaddend..Iadd.53. A fluid flow meter as in claim 52, wherein each of the guide blocks further comprises an extension mounted to each of the guide block inner faces, said extension allowing fluid to pass therethrough. .Iaddend..Iadd.54. A fluid flow meter as in claim 31, wherein the monitor means further comprises means for adjusting the determined fluid flow rate to offset changes of the volume of the quanta of fluid due to changes of the flow rate. .Iaddend..Iadd.55. A fluid flow meter as in claim 54, wherein the adjusting means comprises means for storing respective values of the volume of quanta of fluid at different flow rates. .Iaddend.