Method and apparatus for treating a liquid mixture

• US 5,082,560 A
• Filed: 03/09/1990
• Issued: 01/21/1992
• Est. Priority Date: 03/20/1989
• Status: Expired due to Term

• Current Assignee: Odis Irrigation Equipment Ltd.
• Original Assignee: Odis Irrigation Equipment Ltd.
• Inventors: Marrache, Albert, Eli, Nissim
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): MCCARTHY, NEIL
• Application Number:
  US07/457,547
• Time in Patent Office: 683 Days
• Field of Search: 210/738, 210/787, 210/788, 210/198.1, 210/199, 210/205, 210/206, 210/512.1, 210/498, 210/193
• US Class Current: 210/206
• CPC Class Codes: C02F 1/5281 Installations for water purification using chemical agents

Abstract

A method and apparatus for treating a liquid mixture to separate a clarified fraction therefrom leaving a concentrated sludge fraction involve injecting a flocculent material into the liquid mixture; and inletting the liquid material and the flocculent maerial tangentially into a vertical tank having a perforated plate spaced from its upper end dividing the tank into an upper chamber and a lower chamber, a to produce a flow in the lower chamber having a rotational velocity in the horizontal direction adjacent the outer periphery of the lower chamber, and a lower rotational velocity in the horizontal direction adjacent the center of the lower chamber. The holes in the perforated plate define reduced-area passages from the lower chamber to the upper chamber producing a vertical flow of low velocity in the lower chamber and of higher velocity through the passage in the perforated plate.

Claims

1. Apparatus for treating a liquid mixture to separate a clarified fraction therefrom leaving a concentrated sludge fraction, comprising:

a vertical tank having a perforated plate spaced from its upper end dividing the tank into an upper chamber and a lower chamber;

means for injecting a flocculent material in the liquid mixture;

a tangential inlet in said lower chamber of the vertical tank at a location substantially above its bottom for inletting the liquid mixture and flocculent material tangentially into the lower chamber to produce a flow in said lower chamber having a rotational velocity in the horizontal direction adjacent to the outer periphery of said lower chamber, and a lower rotational velocity in the horizontal direction adjacent to the center of said lower chamber;

the holes in said perforated plate defining reduced-area passages from the lower chamber to the upper chamber producing a vertical flow of low velocity in the lower chamber and of higher velocity through said passages, whereby the flocculent material flocks with most of the solid particles in the liquid mixture at the lower part of the lower chamber and with the remaining solid particles at the upper part of the lower chamber, such that a clarified fraction passes through the holes in the plate to the upper chamber, leaving a concentrated sludge fraction in the lower chamber;

a radial outlet in the upper chamber for outletting the clarified fraction therefrom to produce a radial flow of the clarified fraction in the upper chamber radially across the perforated plate thereby permitting settling of solid particles in the clarified fraction through the perforated plate back to the lower chamber; and

an outlet in the bottom of the lower chamber for outletting the concentrated sludge fraction therefrom.

2. The apparatus according to claim 1, wherein said perforated plate is a flat horizontal plate.

3. The apparatus according to claim 1, wherein said outlet in the lower chamber outletting the concentrated sludge fraction therefrom comprises a conical funnel at the lower end of the lower chamber.

4. The apparatus according to claim 3, wherein said tangential inlet into the lower chamber is located approximately midway between said perforated plate and the upper end of said conical outlet at the lower end of the lower chamber.

5. The apparatus according to claim 1, wherein said means for injecting a flocculent material into the liquid mixture comprises:

a mixing vessel having an inlet pipe connected to the source of the liquid mixture, and an outlet pipe connected to the tangential inlet of the tank;

and an injector connected to said inlet pipe for injecting the flocculent material into the liquid mixture before it enters said mixing vessel such that the flocculent material is mixed with the liquid mixture before the latter is introduced into said tangential inlet of the vertical tank.

6. Apparatus for treating a liquid mixture to separate a clarified fraction therefrom leaving a concentrated sludge fraction, comprising:

a vertical tank having a perforated plate spaced from its upper end dividing the tank into an upper chamber and a lower chamber;

a tangential inlet in said lower chamber of the vertical tank at a location substantially above its bottom for inletting the liquid mixture and flocculent material tangentially into the lower chamber to produce a flow in said lower chamber having a rotational velocity in the horizontal direction adjacent to the outer periphery of said lower chamber, and a lower rotational velocity in the horizontal direction adjacent to the center of said lower chamber;

the holes in said perforated plate defining reduced-area passages from the lower chamber to the upper chamber producing a vertical flow of low velocity in the lower chamber and of higher velocity through said passages, whereby the flocculent material flocks with most of the solid particles in the liquid mixture at the lower part of the lower chamber and with the remaining solid particles at the upper part of the lower chamber, such that a clarified fraction passes through the holes in the plate to the upper chamber, leaving a concentrated sludge fraction in the lower chamber;

a mixing vessel having an inlet pipe connected to the source of the liquid mixture, and an outlet pipe connected to the tangential inlet of the tank;

an injector connected to said inlet pipe for injecting the flocculent material into the liquid mixture before it enters said mixing vessel such that the flocculent material is mixed with the liquid mixture before the latter is introduced into said tangential inlet of the vertical tank;

a radial outlet in the upper chamber for outletting the clarified fraction therefrom to produce a radial flow of the clarified fraction in the upper chamber radially across the perforated plate thereby permitting settling of solid particles in the clarified fraction through the perforated plate back to the lower chamber; and

an outlet in the bottom of the lower chamber for outletting the concentrated sludge fraction therefrom.

7. The apparatus according to claim 6, wherein said perforated plate is a flat horizontal plate.

8. The apparatus according to claim 6, wherein said outlet in the lower chamber outletting the concentrated sludge fraction therefrom comprises a conical funnel at the lower end of the lower chamber.

9. The apparatus according to claim 8, wherein said tangential inlet into the lower chamber is located approximately midway between said perforated plate and the upper end of said conical outlet at the lower end of the lower chamber.