Non-invasive flow measurement

Abstract

An elastomeric acoustic coupler formed by molding a thermoplastic or silicone rubber into a recess of a surgical cassette housing. The coupling has a raised pad to aid in the removal of all air between the transducer and the fluid conduit, and to provide an efficient transmission of an ultrasound signal into the fluid conduit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front perspective view of the cassette of the present invention.

FIG. 2 is a rear perspective view of the cassette of the present invention.

FIG. 3 is an exploded perspective view of the cassette of the present invention.

FIG. 4 is a partial cross-sectional view of the cassette of the present invention.

FIG. 5 is a front perspective view of a surgical console that may be used with the cassette of the present invention.

FIG. 6 is a detailed view of the preferred elastomeric acoustic coupler of the present invention showing a semi-cylindrical raised pad.

FIG. 7 is a detailed view of an alternative elastomeric acoustic coupler showing a circular raised pad.

FIG. 8 is a detailed view of an additional alternative elastomeric acoustic coupler showing a “bread loaf” shaped raised pad.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention and their advantages are best understood by referring to FIGS. 1-3 of the drawings, like numerals being used for like and corresponding parts of the various drawings.

Cassette 10 of the present invention generally includes valve plate 12, body 14 and cover 16. Valve plate 12, body 14 and cover 16 may all be formed of a suitable, relatively rigid, thermoplastic. Valve plate 12 contains a plurality of openings 18 and pumping channel 20 that are sealed fluid tight by elastomers 22 and 24, forming a plurality of fluid paths. Ports 26 provide connectors between cassette 10 and surgical console 100 for the various irrigation and aspiration functions of cassette 10. Such functions may require the use of filter 28. Attached to body 14 is ultrasound reflector 30 and reflector cover 32. Acoustic reflector 30 and reflector cover 32 may be molded as one piece and are located on body 14 to align with transmission window 125 in recess 36 along fluid passage 34 formed in valve plate 12 when valve plate 12 is assembled onto body 14 in the manner shown in FIG. 3. Located within recess 36 on valve plate 12 is elastomeric acoustic coupler 38.

Elastomeric acoustic coupler 38 preferably is formed by over molding an elastomeric material, such as a thermoplastic elastomer or silicone rubber, within recess 36 of valve plate 12. Such a construction method eliminates the need for adhesives to attach elastomeric acoustic coupler 38 to valve plate 12 and ensures the removal of any air from between elastomeric acoustic coupler 38 and valve plate 12.

As best illustrated in FIGS. 6-8, elastomeric coupler 38 consists of body 206, and tab 208 extending from the lower edge of body 206. A lip 200 surrounds the periphery of body 206 and tab 208. The height of lip 200 is preferably about 0.037 inches. A raised central pad 202 is disposed in the approximate center of body 206 and extends downward through the center of tab 208. The height of raised pad 202 is preferably between about 0.030 inches and about 0.050 inches. A thin web 204 of elastomeric material connects raised pad 202 to lip 200. FIG. 6 illustrates the most preferred embodiment where the portion of raised pad 202 disposed on body 206 is semi-cylindrical shaped. In this embodiment, the top and bottom edges of raised pad 202 are co-linear with the interior edge of lip 200. FIG. 7 shows an alternative embodiment wherein the portion of raised pad 202 disposed on body 206 is circular shaped. FIG. 8 shows an additional alternative embodiment wherein the portion of raised pad 202 disposed on body 206 is “bread loaf” shaped.

Recess 36 is located adjacent to fluid passage 34 in valve plate 12 and aligned with acoustic reflector 30 and reflector cover 32 when valve plate 12 is assembled on body 14. When cassette 10 is installed in cassette receiving portion 110 of console 100, ultrasound transducer 120 presses against elastomeric acoustic coupler 38, and tightly compresses raised pad 202 between ultrasound transducer 120 and fluid passage 34. This provides an acoustic coupling between transducer 120 and fluid passage 34, thus allowing the use of ultrasound transducer 120 to measure the fluid flow rate in fluid passage 34. It has been discovered that the disclosed shape of raised pad 202, as described hereinabove, greatly increases the effectiveness of coupler 38.

From the above, it may be appreciated that the present invention provides improved apparatus and methods for using acoustic technology to measure flow rates. An invention such as this eliminates the need for the user to apply the couplant material to the device under use, thereby preventing any misuse of the device. Moreover, an invention such as ensures repeatable contact between the transducer, the couplant, and the fluid conduit, and ensures the removal of air between the transducer and the couplant, as well as between the couplant and the fluid conduit. Furthermore, an invention such as this will provide a higher signal to noise ratio for the transmitted ultrasound signal, will require zero settling time of the elastomer material while under pressure by the ultrasound transducer, will provide good sensitivity for ultrasound signal transmission and reception, and will allow high flow rate measurement reliability.

It is believed that the operation and construction of the present invention will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims.

Claims

1. An elastomeric acoustic coupler, comprising: a body;a lip surrounding a peripheral edge of said body;a raised central pad disposed proximate a center of said body; anda web connecting said pad to said lip.

2. The elastomeric acoustic coupler of claim 1 wherein said raised pad is semi-cylindrical shaped.

3. The elastomeric acoustic coupler of claim 1 wherein said raised pad is circular shaped.

4. The elastomeric acoustic coupler of claim 1 wherein said raised pad is bread loaf shaped.

5. The elastomeric acoustic coupler of claim 1 wherein a height of said lip is approximately 0.037 inches.

6. The elastomeric acoustic coupler of claim 1 wherein height of said pad is between about 0.030 inches and about 0.050 inches.

7. The elastomeric acoustic coupler of claim 1 further comprising a tab connected to said body.

8. The elastomeric acoustic coupler of claim 1 wherein said raised pad has a portion that extends onto said tab.

9. A surgical cassette, comprising: a cassette body having a plurality of fluid passages, wherein one of said plurality of fluid passages has a recess disposed therein; andan acoustic coupler disposed in said recess, said coupler having: a body;a lip surrounding a peripheral edge of said body;a raised central pad disposed proximate a center of said body; anda web connecting said pad to said lip.

10. The surgical cassette of claim 9 wherein said raised pad is semi-cylindrical shaped.

11. The surgical cassette of claim 9 wherein said raised pad is circular shaped.

12. The surgical cassette of claim 9 wherein said raised pad is bread loaf shaped.

13. A surgical system, comprising: a surgical console, the surgical console having a cassette receiving portion;an ultrasonic transducer located in the cassette receiving portion of the surgical console, the ultrasonic transducer adapted for measuring fluid flow in a fluid passage;a surgical cassette having a plurality of fluid passages; andan acoustic coupler attached to the cassette, the acoustic coupler acoustically coupling the ultrasonic transducer to the cassette when the cassette is installed within the cassette receiving portion of the surgical console so as to allow the ultrasonic transducer to measure fluid flow in at least one of the plurality of fluid passages in the cassette, said acoustic coupler having:a body;a lip surrounding a peripheral edge of said body;a raised central pad disposed proximate a center of said body; anda web connecting said pad to said lip.

14. The surgical system of claim 13 wherein said raised pad is semi-cylindrical shaped.

15. The surgical system of claim 13 wherein said raised pad is circular shaped.

16. The surgical system of claim 13 wherein said raised pad is bread loaf shaped.