Gas/Liquid Separator

This patent application is copending with my related patent application entitled "Combined Centrifugal Force/Gravity Gas/Liquid Separator" filed on the same date as subject patent application.

1. Field of the Invention

The present invention relates generally to gas/liquid separators, and more particularly to gas/liquid separators that use centrifugal force to separate the gas from the liquid.

2. Description of the Prior Art

A gas/liquid separator (also called a hydrocyclone) facilitates the separation of gases from gas/liquid mixtures. One type of gas/liquid separator is known as a centrifugal separator. Typically, the gas/liquid mixture is introduced into a conical housing where the mixture is forced to spin therein. As the mixture is spun, the heavier liquid moves due to centrifugal force, to the walls of the housing while the gas, being lighter, migrates inward. In the case of conical housings, efficiency of separation is usually only about 50% because some of the liquid remains entrained within the gas while separated liquid exits the apex of the cone via gravity. The residual gas/liquid mixture flows out through the center of the cone through a hollow outlet tube called the vortex finder. See, for example, Suh, et al, U.S. Pat. No. 4,617,031, issued Oct. 14, 1986. Attempts at improving separation efficiency while increasing flow volume include increasing the size of the separating vessel or using a multiplicity of small volume separators in tandem. However, either of these options results in greater equipment costs and space requirements.

Accordingly, it is an object of the present invention to provide a gas/liquid separator that achieves high efficiency gas separation while minimizing cost and space requirements.

It is another object of the present invention to provide a high efficiency gas/liquid separator that is capable of handling high volume flow rates.

Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.

In accordance with the present invention, a gas/liquid separator is provided. The separator includes a hollow cylindrical separator body having: 1) an inlet port in a top sidewall thereof for receiving a tangential inflow of a gas/liquid mixture, and 2) an outlet port in a bottom sidewall thereof for allowing liquid separated from the mixture to tangentially exit the cylindrical separator body. The inlet port and outlet port are located 90.degree. apart. A hollow cylindrical vortex finder is positioned concentrically within the cylindrical separator body. The vortex finder has: 1) first gas entrance ports aligned with the inlet port of the separator body for receiving a primary gas flow separated from the mixture, and 2) second gas entrance ports aligned with the outlet port of the separator body for receiving a secondary gas flow separated from the mixture. The cylindrical vortex finder is further provided with means to allow the primary and secondary gas flows to exit same.

FIG. 1 is a perspective view of the gas/liquid separator according to the teachings of the present invention;

FIG. 2 is a cross-sectional view at the point where the inlet flow line connects to the separator body to reveal a rectangular inlet port;

FIG. 3 is an isolated, side view of the hollow, cylindrical vortex finder provided concentrically within the separator body of the present invention;

FIG. 4 is a top view of the separator body with its end cap removed for viewing separated gas and separated liquid flow therein; and

FIGS. 5(a)-5(d) are graphs showing the experimental separation efficiencies for four different flow rates passing through a gas/liquid separator designed according to the present invention.

Referring now to the drawings, and in particular to FIG. 1, a perspective view of the gas/liquid separator is shown and is referenced generally by the numeral 10. Separator 10 includes a hollow, cylindrical separator body 12 capped at either end by end caps 14a and 14b which may be used to mount separator 10 in a gas/liquid flow system (not shown). The perspective view of FIG. 1 is further cut away at a central portion thereof to reveal a hollow, cylindrical vortex finder 16 passing concentrically through separator body 12.

At the top of separator body 12, an inlet flow line 20 is connected thereto in a tangential fashion. Inlet flow line 20 introduces a tangential flow of a gas/liquid mixture into separator body 12. The gas/liquid mixture is indicated by flow arrow 100. At the point where inlet flow line 20 connects to separator body 12, as shown in the cross-sectional view of FIG. 2, a rectangular inlet port 22 is provided in the side wall of separator body 12 having a height H and a width W. Rectangular inlet port 22 serves to squeeze the incoming flow 100 into a rectangle in order to make same a tangential flow within separator body 12. For good tangential flow, the height-to-width ratio, or H:W, for port 22 is preferably at least 2:1.

At the bottom of separator body 12, an outlet flow line 30 is provided. Outlet flow line 30 allows liquid separated from the gas/liquid mixture of flow 100, as indicated by flow arrow 201, to exit separator body 12 in a tangential fashion. At the point where outlet flow line 30 connects to separator body 12, a rectangular outlet port (not shown) is provided in the side wall of separator body 12 to communicate with outlet flow line 30. The rectangular outlet port communicating with outlet flow line 30 is dimensioned to be identical with rectangular input port 22 and faces in a direction that is offset by 90.degree. with respect to rectangular inlet port 22.

Gas separated from the gas/liquid mixture of flow 100 leaves separator body 12 via vortex finder 16. Shown in greater detail in the isolated side view of FIG. 3, vortex finder 16 is provided with a plurality of identically sized and shaped gas entrance ports 18 located around vortex finder 16 at both the upper 16a and lower 16b ends thereof. The ports 18 located at the lower end 16b of vortex finder 16 are symmetrical with the ports located at the upper end 16a. Symmetry is with respect to the center 16c of vortex finder 16. Accordingly, a description of ports 18 at the upper end 16a is sufficient to describe the ports 18 at the lower end 16b.

In particular, the ported area of gas entrance ports 18 at the upper end 16a of vortex finder 16 should be approximately equal to that of rectangular inlet port 22 of separator body 12. Furthermore, the length L of each port 18 is preferably equal to the height H of rectangular inlet port 22, and should also be aligned top-to-bottom in the same horizontal plane of rectangular inlet port 22.

Three ports 18 are provided in the upper end 16a of vortex finder 16 and are spaced (on center) 120.degree. apart from one another. Each port 18 can be thought of as two vertically aligned slot portions 18a and 18b of respective slot widths W.sub.a and W.sub.b and respective longitudinal lengths L.sub.a and L.sub.b. Slot portion 18a is dimensionally wider and longer than slot portion 18b.

The operation of the present invention will now be described with reference to FIGS. 1-4. A gas/liquid mixture 100 is introduced tangentially into separator body 12 via rectangular inlet port 22. The resulting flow created in separator body 12 is shown in FIG. 4. FIG. 4 is a top view of separator body 12 with end cap 14a removed for purposes of description. As gas/liquid mixture flow 100 enters separator body 12, the heavier liquid separates from the mixture and moves to the outermost portion of separator body 12 as indicated by solid flow arrows 200. Simultaneously, the lighter gas separating from the liquid, spins around vortex finder 16 as shown by dashed flow arrows 300. A uniformly shaped cylinder of separated gas is thereby formed in separator body 12.

Since both rectangular inlet port 22 and the rectangular outlet port communicating with outlet line 30 are identically sized, the cylinder of separated gas 300 remains stable thereby improving separation efficiency. The separated gas 300 exits the separator body 12 via the gas entrance ports 18 located at the upper 16a and lower 16b ends of vortex finder 16. The separated gas exits vortex finder 16 via a gas exit port located in end cap 14a as indicated by flow arrow 301 in FIG. 1.

The stability of the cylinder of separated gas 300 within separator body 12 is also due to the horizontal alignment of the ports 18 with the respective rectangular ports in the sidewalls of separator body 12. Also, by making the area of the respective rectangular ports equal to the combined area of the correspondingly aligned ports 18 in vortex finder 16, the stability of the cylinder of separated gas 300 and therefore, separation efficiency, are further enhanced. Finally, the symmetry between the upper 16a and lower 16b ends of vortex finder 16 also contribute to the stability of the cylinder of separated gas 300.

Separation efficiency for the above described design is best shown by way of experiment. The dimensions used for the various ports of separator 10 as shown in FIG. 3 are as follows:

A gas/liquid mixture consisting of helium/water (0.1 to 3 cubic feet per minute of gas and a flow rate of one of 100, 140, 160 or 200 gallons per minute of liquid) was submitted to the separator designed according to the above description and dimensions. Separation efficiency results are presented for the above mentioned flow rates respectively in FIGS. 5(a)-5(d). It is clear that the above design achieves approximately 100% separation efficiency regardless of the flow rates between 100-200 gallons per minute. Other flow rates/gas flow rates could easily be accommodated by adjusting the dimensions of the rectangular inlet/outlet ports and those of the vortex finder.

It will also be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.