US3709428A - Centrifuge vent - Google Patents

Abstract

A continuous flow, annulus type centrifuge which includes a vent to provide an escape path for air or gas accumulation.

Description

[ 51 Jan. 9, 1973 [56] References Cited UNlTED STATES PATENTS [54] CENTRIFUGE VENT [75] Inventor: Jack W. Abbott, Huntington Beach,

Calif.

The Garrett Corporation, Los An- 239,659 4/1881 Houston at geles, Calif. 2,985,361

5/196! Smith................... 11/1965 Assignee:

3,2l9,264 Cox 221 Filed:

April 13, 1970 [21] App], No: ,27926 Primary Examiner-Jordan Franklin Assistant Examiner-George H. Krizmanich Att0rney--Albert J. Miller and John N. Hazelwood annulus type centrifuge which invide an escape path for air or gas T C A R T S B A m WP 0 m St UH 03 UV .ma MS mm 5 1| [AC AMQnR 9/ 1 1 llS 3 4 3 ,0 ZMSZ 2 m n M W30 i 2 mu R mm 9 "1 nm/, muwA mm29 u U/ 3 n 1 "NW2 mn c Ar. "3 8 "ms I C l sm UIF 1]] 218 555 [[l.

accumulation.

5 Claims, 1 Drawing Figure CENTRIFUGE VENT BACKGROUND OF THE INVENTION equal to that developed in the outer annulus. For a high speed centrifuge, the pressure in the outer annulus may reach several thousand psi and to rely upon the main feed pump becomes impractical because of the extremely high discharge head required.

SUMMARY OF THE INVENTION A vent tube is incorporated into the inlet of the continuous flow centrifuge to provide an escape path for any gas accumulated or trapped between the inner and outer radius of the centrifuge. A pressure relief valve may be associated with this vent.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is a cross-sectional view of the centrifuge of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated, the centrifuge includes an outer shell 12 and an inner drum or barrel 14 supported within the outer shell 12 by a plurality of spaced studs 16 and piloting rings 18. An inlet 20, including pump 21, provides access to the space between the inner barrel 14 and outer shell 12. The inlet 20 is supported by bearings 22 and includes rotary seals 24. The outlet 26 at the opposite end of the centrifuge 10 is likewise supported by bearings 28 and includes rotary seals 30. A drive system such as the belt 32 (around the outlet 26) driven by a prime mover (not shown) can be used to rotate the centrifuge. Flow splitter 34 is provided at the bottom of the centrifuge 10 between the outer shell 12 and the inner barrel l4 and includes fluid discharge 36. Outlet 26 and discharge 36 include valves 38 and 40 respectively.

Extending downward through the inlet 20 into the area between the inner barrel 14 and the outer shell 12 is the vent tube 42. This vent tube 42 includes valve 44 which may be a simple gate valve or a pressure relief valve controlled by the pressure at the lower end of the vent.

The centrifuge I0 is designed for continuous flow and may be utilized to either remove small particles (particularly in the submicron region) from a slurry provided there is sufficient difference in density between the particles and the slurry or to separate two nonmiscible fluids having a sufflcient density differencc.

During start-up of the centrifuge 10, the mixture of fluids, for example, oil and water is pumped through the centrifuge from inlet 20 to outlets 26 and 36. As the rotational speed of the centrifuge is increased, the flow path from the inner radius to the outer radius will usually be blocked by air bubbles 50 in this region. At

the high speeds for which this centrifuge is designed, the pressure in the outer annulus will reach several thousand psi which makes it uneconomical to overcome this blockage by forcing the air through this centrifuge with the pump 21. By opening the valve 44, these air bubbles can be removed through the vent 42 and permit the flow of the oil-water mixture through the centrifuge.

Once steady state operation of the centrifuge is accomplished, which is that illustrated, entrained air may tend to collect in this same region between the inner and outer radius and again cause some restriction if not blockage. This build up of air bubbles 50 can again be relieved by venting through vent 42. The valve 44 can serve as a pressure relief valve such that it will open and permit venting when the pressure at the lower end of the vent 42 exceeds a certain predetermined value. To be effective, this vent tube must be: at least 5 percent of the inlet flow area but not more than 15 percent, with 10 percent being preferable. The vent should be positioned in the center of the inlet tube and must exceed downward to the region where the fluid turns outward.

The separation of the lighter fluid (oil) from the heavier fluid (water) is accomplished by the flow splitter plate 34 which collects the lighter density oil and discharges it through discharge 36, while the higher density water flows around the flow splitter plate 34 and out through outlet 26.

In this manner the high speed centrifuge can be easily started without the requirement for an extremely high discharge head pump and can be run continuously without air or gas bubbles restricting flow.

While specific embodiments of the invention have been illustrated and described, it is to be understood that these embodiments are provided by wayof example only and that the invention is not to be constructed as being limited thereto, but only by the proper scope of the following claims.

What I claim is: 1. A centrifuge comprising: an outer cylindrical drum having a central axially extending inlet means at one end thereof and a central axially extending outlet means at the opposite end thereof;

means to rotatably support said outer cylindrical drum; i

a cylindrical inner drum concentrically disposed within said outer cylindrical drum forming an outer annular flow path between said inner and outer drums and a radial flow path in the area of said inlet means; and I a vent tube disposed within the central axially extending inlet means, said vent tube having an end extending to the radial path and spaced from one end of the inner drum to provide an escape path for air or gas accumulations.

2. The centrifuge of claim 1 and in addition valve means operably associated with said vent tube.

3. The centrifuge of claim 2 wherein said valve means is gas pressure responsive means.

4. The centrifuge of claim 2 wherein the flow area of said vent tube is between 5 and 15 percent of the flow area of said outer cylindrical drum inlet means.

5. The centrifuge of claim 2 wherein the flow area of said vent tube is approximately 10 percent of the flow area of said outer cylindrical drum inlet means.

Claims (5)

1. A centrifuge comprising: an outer cylindrical drum having a central axially extending inlet means at one end thereof and a central axially extending outlet means at the opposite end thereof; means to rotatably support said outer cylindrical drum; a cylindrical inner drum concentrically disposed within said outer cylindrical drum forming an outer annular flow path between said inner and outer drums and a radial flow path in the area of said inlet means; and a vent tube disposed within the central axially extending inlet means, said vent tube having an end extending to the radial path and spaced from one end of the inner drum to provide an escape path for air or gas accumulations.

2. The centrifuge of claim 1 and in addition valve means operably associated with said vent tube.

3. The centrifuge of claim 2 wherein said valve means is gas pressure responsive means.

4. The centrifuge of claim 2 wherein the flow area of said vent tube is between 5 and 15 percent of the flow area of said outer cylindrical drum inlet means.

5. The centrifuge of claim 2 wherein the flow area of said vent tube is approximately 10 percent of the flow area of said outer cylindrical drum inlet means.

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