Means for counting drops

• US 4,635,281 A
• Filed: 11/23/1984
• Issued: 01/06/1987
• Est. Priority Date: 11/23/1984
• Status: Expired due to Fees

• Current Assignee: Jones J. Paul
• Original Assignee: Jones J. Paul
• Inventors: Jones, J. Paul
• Primary Examiner(s): Heyman, John S.
• Application Number:
  US06/674,406
• Time in Patent Office: 774 Days
• Field of Search: 377/21, 250/577, 604/251, 604/253
• US Class Current: 377/21
• CPC Class Codes: A61M 5/1689 Drip counters
• CPC Class Codes: G01F 3/00 Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow measuring a proportion of the volume flow G01F5/00

Abstract

A light source to project a light beam along an axis to a receiver means intermediate the source and the receiver to cause the light to refract so that the light reaching the receiver is substantially reduced; means to periodically introduce a quantity of liquid into the area where the light is refracted, the liquid changing the amount of refraction whereby the light reaching said receiver is substantially increased; and means to detect each said change in light at said receiver and count same.

Claims

1. For use with means to permit a body of clear fluid to move downwardly drop by drop, mechanism to count the number of drops comprising:

a pair of elongated members made of light conducting material;

on each said member, a gap surface formed as a light refractive grating;

means supporting said members to extend in a generally vertical direction with said gap surfaces facing one another to form a generally vertically extending gap;

each member, at the top end of said gap, being formed with a slanted surface, the slanted surfaces facing one another and forming a guide to receive each of said drops and direct each drop into said gap;

said slanted guide surfaces attracting the fluid of a drop impinging thereon with the attraction forces between the fluid and the slanted surfaces and the cohesive force of the fluid, providing that the fluid moves down through the guide as a unitary mass into the gap under the influence of gravity;

said gap surfaces attracting the fluid of the drop entering the gap with the attraction forces between the fluid and gap surfaces providing that the fluid moves down as a unitary mass through the gap under the influence of gravity;

a light source adjacent to one of said members and a light receiver adjacent to the other of said members, the light source being oriented to project a beam of light through said first member, through said gap, through said second member, and thence to said light receiver;

said gap surfaces, in the absence of said liquid therebetween, refracting the light from the source so that the quantum of light received by the light receiver is less than the quantum of light from the source, and with the presence of said liquid between said gap surfaces changing the amount of said refraction whereby the quantum of light received by the receiver is substantially increased, said increase in light reaching the receiver signifying the presence or absence of a drop in said gap; and

means connected to said receiver and operative as a function of said change in light to count the number of changes and thereby count the number of drops passing through said gap.

2. Mechanism for use with means to permit body of clear fluid to move downwardly drop by drop, the mechanism comprising:

a pair of elongated members made of light-conducting material;

on each said member, a gap surface formed as a light refractive grating;

on each member, supporting means supporting the member to extend in a generally vertical direction and respectively supporting the members with said gap surfaces facing one another to form a generally vertically extending gap;

said supporting means for each elongated member being connected to its member at least in an area opposite the gap surface and in the connection area being integral with the member and being made of light-conducting material;

each member, at the top end of said gap, being formed with a slanted surface, the slanted surfaces facing one another and forming a guide to receive each of said drops and direct each drop into said gap;

said slanted surfaces attracting the fluid of a drop impinging thereon with the attraction forces between the fluid and the slanted surfaces and the cohesive force of the fluid providing that the fluid move down through the guide as a unitary mass into the gap under the influence of gravity; and

said gap surfaces attracting the fluid of the drop entering the gap with the attraction force between the fluid and gap surfaces providing that the fluid moves down as a unitary mass through the gap under the influence of gravity.

3. A method of detecting the presence of a clear liquid medium:

forming and projecting a light beam along an axis from a source of light to a receiver of light;

intermediate said source and said receiver, causing the light to refract so that the light reaching the receiver is substantially reduced;

periodically introducing a quantity of liquid into the area where the light is refracted, the liquid changing the amount of refraction whereby the light reaching said receiver is substantially increased; and

detecting each said change in light at said receiver and counting each change.

4. In a drip chamber for a medical infusion system:

a hollow, generally vertically extending housing having a top wall, a bottom wall, and a side wall which form a chamber, the side wall including first and second flat walls of uniform thickness which are parallel to one another and the parallel walls being made of light conducting material;

means on said top wall permitting clear fluid to fall, drop after drop, into said chamber;

means on said bottom wall permitting fluid in the chamber to exit therefrom;

a first elongated member of said chamber and integral with said first parallel wall and made of the same material as said first parallel wall;

a second elongated member inside of said chamber and integral with said second parallel wall and made of the same material as said second parallel wall;

on each said member, a gap surface formed as a light refractive grating and the respective gap surfaces facing one another to form a generally vertically extending gap;

each member, at the top end of said gap, being formed with a slanted surface, the slanted surfaces facing one another and forming a guide to receive each of said drops and direct each drop into said gap;

said slanted surfaces attracting the fluid of a drop impinging thereon with the attraction forces between the fluid and the slanted surfaces and the cohesive force of the fluid providing that the fluid move down through the guide as a unitary mass into the gap under the influence of gravity;

said gap surfaces attracting the gluid of the drop entering the gap with the attraction force between the fluid and gap surfaces and the cohesive force of the fluid providing that the fluid moves down as a unitary mass through the gap under the influence of gravity;

a light source adjacent said first parallel wall and a light receiver adjacent said second parallel wall, the light source being oriented to project a beam of light through said parallel wall, through said first member, through said gap, through said second member, through said second parallel wall, and thence to said light receiver;

said gap surfaces, in the absence of said liquid therebetween, refracting the light from the source so that the quantum of light received by the light receiver is less than the quantum of light from the source and the presence of said liquid between said gap surfaces changng the amount of said refraction whereby the quantum of light received by the receiver is increased, said change in light reaching the receiver signifying the presence or absence of a drop in said gap; and

means connected to said receiver and operative as a function of said change in light to count the number of changes and thereby count the number of drops passing through said gap.