Single drop separator

• US 4,148,718 A
• Filed: 10/19/1977
• Issued: 04/10/1979
• Est. Priority Date: 06/10/1976
• Status: Expired due to Term

• Current Assignee: Coulter Electronics, Inc.
• Original Assignee: Coulter Electronics, Inc.
• Inventors: Fulwyler, Mack J.
• Primary Examiner(s): Hill, Ralph J.
• Application Number:
  US05/843,696
• Time in Patent Office: 538 Days
• Field of Search: 209/3, 209/11, 209/111.5, 209/111.7, 209/127 R, 209/127 A, 209/127 C, 239/3, 239/15, 346/75, 346/1
• US Class Current: 209/3.1
• CPC Class Codes: B03C 5/02 Separators
• CPC Class Codes: B03C 9/00 Electrostatic separation not provided for in any single one of the other main groups of this subclass
• CPC Class Codes: G01N 15/12 by observing changes in resistance or impedance across apertures when traversed by individual particles, e.g. by using the Coulter principle
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1019 Associating Coulter-counter and optical flow cytometer [OFC]
• CPC Class Codes: G01N 2015/1406 Control of droplet point
• CPC Class Codes: Y10S 209/906 Pneumatic or liquid stream feeding item

Abstract

A method and apparatus for forming a separate single drop wherein a fluid stream is formed in air and an electrical charge or radiant energy is applied to the stream at a particular location in order to disturb the stream and create a single drop. The drop may be formed surrounding a particle and the drop may be charged when formed, then deflected for separate collection.

Claims

1. A method for selectively separating small particles suspended in a fluid including the steps of:

forming a moving fluid stream in air having a substantially constant velocity with said particles asynchronously spaced in said stream, sensing a particle in said moving fluid stream, and applying one of an electrical pulse and a quantum of radiant energy to said stream in air at a particular location when said sensed particle passes through said particular location for asynchonously disturbing said stream and creating a single isolated droplet from said stream surrounding said particle separated from the preceding and succeeding fluid stream.

2. The method of claim 1 wherein said electrical pulse is applied by an electrode communicating with said fluid stream.

3. The method of claim 1 wherein said radiant energy is applied by directing a high intensity light beam into said fluid stream.

4. The method of claim 1 wherein said radiant energy is applied by a heat probe communicating with said fluid stream.

5. The method of claim 1 wherein one of said electrical pulse and radiant energy is applied for a predetermined duration and has a predetermined amplitude.

6. The method of claim 5 wherein said electrical pulse is a voltage in a range of 50 to 250 volts in amplitude.

7. The method of claim 5 wherein said electrical pulse is a voltage applied for a predetermined duration in the range of 5 to 50 microseconds.

8. The method of claim 5 wherein said electrical pulse is a voltage which rises abruptly from a first level to a second level, decreases slowly to a third level between said first and second level, and decreases from said third level to said first level abruptly.

9. The method of claim 5 wherein said electrical pulse is a voltage pulse having a predetermined duration, said pulse having a higher initial voltage than terminal voltage.

10. The method of claim 1 wherein said droplet is created by separating from said fluid stream at a second location and further including the step of applying a second electrical pulse at said second location as the droplet separates from said fluid stream for charging said droplet.

11. The method of claim 10 further including the step of deflecting said separated and charged droplet.