US3650637A

US3650637A - Asymmetrical jet ejector

Info

Publication number: US3650637A
Application number: US31897A
Authority: US
Inventors: David W Amick
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-04-27
Filing date: 1970-04-27
Publication date: 1972-03-21
Anticipated expiration: 1989-03-21

Abstract

An asymmetrical jet ejector having a bend along the conduit axis in the direction of the primary fluid flow and an inlet at the inner radius of the bend for the secondary fluid. The differential pressure at the inlet between the pressure of the secondary fluid and the primary fluid at the inner radius of the bend produces a flow of the secondary fluid into the conduit. The energy in the primary flow thereby induces and entrains the flow of the secondary fluid.

Description

llnited States Patent Amiclt Mar. 211, 1972 541 ASYMMETRIHCAL JET EJECTOR 2,068,363 1/1937 Wetmore et a1. ..417/1s1 x 2,382,391 8 1945 B ..41 1 72 Inventor: David w. Amick, 6437 Meha St., Sprmg- 7/ 98 field 22150 Primary Examiner-Carlton R. Croyle [22] Filed: Apr. 27, 1970 Assistarit Examiner-Richard E. Gluck Attorney-R. S. Sciascia and Q. E. Hodges [21] Appl. No.: 31,897

[57] ABSTRACT [52] U.S. Cl ..417/151 An asymmetrical jet ejector having a bend along the conduit [51] llnt. Cl .JFMf 5/00 axis in the direction of the primary fluid flow and an inlet at [58] Field ol'Search... ....417/151, 169, 170, 198, 197, the inner radius of the bend for the secondary fluid. The dif- 7 19 95 94 17 150 173 179 1 1 125 ferential pressure at the inlet between the pressure of the secondary fluid and the primary fluid at the inner radius of the [56] References Cited bend produces a flow of the'secondary fluid into the conduit. The energy in the primary flow thereby induces and entrains UNITED STATES A N S the flow of the secondary fluid.

3,215,088 11/1965 Schlichtigo ..417/151 5 Claims, 4 Drawing Figures Patented March 21, 1972 2 Sheets-Sheet l INVENTOR. DA VID W. AMICK ATTORNEY Patented March 21, 1972 2 Sheets-Sheet 2 INVENTOR.

DAVID W. AMICK AT TORNE Y ASYMMETRICAL JET EJECTOR The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.

SUMMARY OF THE INVENTION A jet ejector or jet purnp are names given to those devices which use a primary fluid'to pump a secondary fluid. This invention relates to a jet ejector and specifically relates to an asymmetrical jet ejector having a conduit with a bend in the axial direction of the primary flow and an inlet for the secondary fluid at one side of the axis of primary flow. Prior art jet ejector pumps used axis-symmetric primary and second fluid conduits. The fluid flowing in the primary conduit induced the secondary fluid flow and ejected the fluids in the direction of the exhaust port. Variations of the axis-symmetric jet ejector introduced the secondary flow at an angle to the primary flow, however the primary flow was in a substantially straight axial direction and performance was in no way dependent upon the point in the primary fluid flow at which the secondary fluid was introduced.

This invention utilizes a well known principle that fluid flowing through a bend in a pipe or conduit will experience a minimum pressure at its point of greatest flow velocity, at the inside of the turn, and maximum pressure at the point of minimum flow velocity, at the outside of the turn. The point of lowest pressure, at the inside of the turn is utilized to inject a secondary fluid flow at that point so that the differential pressure between the pressure of the secondary fluid and the pressure of the primary fluid is maximum and maximum secondary fluid flow is obtained. The conduit downstream of the bend in the direction of flow can be the shape of a variable area diffuser. As described hereinafter, the variable area diffuser smooths the flow through the conduit, causing the velocity of the fluid through the conduit to be substantially uniform and thereby enhances the efficiency of the jet action pump.

Accordingly, it is one object of this invention to provide a new and improved jet ejector pump.

It is a second object of this invention to provide a new and improved jet ejector pump which will operate under a variety of conditions including unsteady flows, compressible and incompressible fluids, dissimilar fluids and rotational and unrotational flows.

It is a third object of this invention to provide a new and improved jet ejector pump for steam power plant condensers, and gas turbine exhaust eductors to ventilate engine compartments and jet water pumps for deep wells.

These and other objects of the invention will be apparent from the accompanying drawings in which:

FIG. 1 is a schematic view of one embodiment of the jet ejector having a conduit turn in the primary fluid axial flow direction and a secondary fluid inlet at the inner radius of the turn and at an angle of 45 degrees to direction of primary fluid flow. The ejector downstream of the turn is a constant area diffuser. The schematic shows the velocity profiles of the flow at particular stages in the flow.

FIG. 2 is a schematic view of a second embodiment of the jet ejector having a conduit turn in the primary fluid axial flow direction and a secondary fluid inlet at the inner radius of the turn and at an angle of 45 degrees to the direction of primary fluid flow. The ejector, downstream of the turn, is a variable area diffuser. The schematic shows the velocity profiles of the flow at particular stages in the flow.

FIG. 3 is a cross-sectional view of a third embodiment of the invention and is in accordance with the schematic of FIG. 1. In this embodiment, the secondary fluid inlet is perpendicular to the direction of primary fluid flow and the conduit downstream of the turn is in the shape of a constant area diffuser.

FIG. 4 is a cross-sectional view of a fourth embodiment of the invention and is in accordance with the schematic of FIG.

1. In this embodiment, the secondary fluid inlet is parallel to the direction of primary fluid flow and the conduit downstream of the turn is the shape of a constant area diffuser.

Reference is now made to FIG. 1 showing one embodiment of the jet ejector pump made from an integral and continuous conduit 9 having a primary fluid flow portion 11 with a primary fluid flowing through sectionll in the direction denoted by arrow 10 and with a velocity profile at stage A shown by the arrow 13. Downstream of the primary flow there is a bend 12 in the conduit. The velocity profile of the primary fluid flow through the bend at stage B is shown by the arrow 15. At the inner radius 16 of the bend 12 an entrance port 17 is provided for the secondary fluid flow. The velocity profile of the secondary fluid flow is shown by arrow 19. Downstream of the bend and the entrance port 17 is conduit section 14. The cross-sectional area of section 14 is substantially equal to the combined cross-sectional areas of the bend 12 and the entrance ports 17. The velocity profile of the combined primary and secondary flow in section 14 is shown at stage D by arrow 21. The direction of the combined primary and secondary flow is shown by arrow 22, the direction of primary flow in the bend is shown by arrow 8 and the direction of the secondary flow entering at port 17 is shown by arrow 20.

In operation of the jet ejector the primary fluid flow 10 is introduced by any suitable means. The velocity of the primary fluid in section 11 is shown by arrow 13 to be substantially equal over the cross section of conduit 11 and decreasing slightly for that portion of the flow closest to the inner surface of the conduit. The primary flow is turned in the direction of section 14 by the bend 12. As shown by the velocity profile at stage B the velocity of the flow will be greatest at the inside radius of the turn 16 as smallest at the outside radius of the turn 18. As is well known, where the velocity is greatest at 16 the pressure of the fluid will be least and where the velocity is least at 18 the pressure of the fluid will be greatest. The secondary fluid enters at port 17 in the direction shown by arrow 20. Port 17 lies in a plane which intersects the bend in the conduit and which lies at an angle of degrees to the direction of the primary fluid flow as shown by arrow 10 and is defined by edge 41 of bend 12 at inner radius 16 and by edge 42. The rate or velocity at which the secondary fluid enters the conduit at port .17 will depend upon the differential pressure existing between the secondary fluid at port 17 and the pressure of the primary fluid at the inner most radius 16 of the bend 12. The secondary fluid may be introduced under a pressure greater or less then ambient or may be at ambient pressure.

The energy of the primary fluid in the turn is thereby used to induce and entrain the secondary fluid entering at port 17. The combined primary and secondary fluid flow then continues downstream of bend 12 through conduit section 14, the

velocity profile of the fluid flow in conduit 14 shown at stage D by arrow 21. The fluid flow is in the direction shown by arrow 22.

Reference is now made to FIG. 2 showing a second embodiment of the jet ejector pump 9 in schematic form and substan tially as shown in FIG. 1 wherein like reference characters designate like or corresponding parts.

Conduit section 14 downstream of the bend and the secondary fluid entrance port 17 is substantially equal in cross-sectional area to the combined crosssectional area of the bend 12 and the entrance port 17. Continuous and integral with section 14 is conduit section 23 in the shape of a variable area diffuser. Conduit section 24 is continuous and integral with conduit section 23 and is of a constant cross-sectional area equal to the maximum cross-sectional area of the diffuser at stage C.

The diffuser 23 smoothes the combined flow of primary and secondary fluids through it and makes the flow velocity substantially uniform through conduit 24, as shown by velocity profile 21 at stage D. The smooth flow obtained in the direction of arrow 22 by using a diffuser, enhances the efficiency of the pump. Placement of the diffuser may be at the edge 42 of the secondary fluid inlet port or may be placed downstream of the port 17 with a continuous and integral connecting conduit section 14, as shown.

Reference is now made to FIG. 3 showing a third embodiment of the jet ejector pump, the embodiment being in accordance with the schematic of FIG. 1. This second embodi ment is shown in cross-sectional view and substantially as shown in FIG. 1 wherein the reference characters designate like or corresponding parts. In this embodiment the secondary fluid flow entrance 50 lies in a plane perpendicular to the direction of primary fluid flow and is defined by the edge 51 of bend 12 at inner radius 16 and by lip 52 continuous and integral with conduit 14.

Reference is now made to FIG. 4 showing a fourth embodiment of the jet ejector pump the embodiment being in accordance with the schematic of FIG. 1. This second embodiment is shown in cross-sectional view and substantially as shown in FIG. 1 wherein the reference characters designate like or corresponding parts. In this embodiment, the secondary fluid flow entrance port 60 lies in a plane parallel to the flow of the primary fluid as shown by arrow 10, and is defined by edge 61 at the inner radius 16 of bend l2 and by edge 62 of conduit section 14.

The invention is not limited to the embodiments shown herein. These preferred embodiments are provided in accordance with the patent laws to completely disclose to one skilled in the art how to make and use the invention. The preferred embodiments may be varied as follows: The entrance port of the secondary fluid may assume any angle with respect to the direction of the primary fluid flow and is not considered limited to the embodiment showing the three angles of zero, 45, and 90, with respect to the primary fluid flow direction. Also the jet ejector pump may be used with or without the diffuser 24 shown in the schematic of FIG. 2. In addition the jet ejector pump may be used with the secondary fluid entrance port at any angle with respect to the direction of the primary fluid flow, the invention not being limited to the embodiment shown in FIG. 2. The primary or secondary fluids may be either compressible or incompressible. The primary and secondary fluids may be dissimilar fluids. The primary and secondary fluid flow may be steady or may be unsteady or either one may be unsteady with the other steady. Either the primary or secondary fluids may be rotational or irrotational. The bend 12 may be any angle of turn relative to the direction of the primary flow, a minimum angle of turn is only required to produce a varying velocity profile within the turn. The shape of the duct may be circular, rectangular, or any other shape which is convenient to the application. The pressure of the secondary fluid may be greater or less then ambient pressure or may be at ambient pressure.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A jet ejector pump comprising:

a pumping means;

means having at least two axes and transporting said pumping means in at least two nonparallel axial directions and being continuous in at least the area of directional change;

means at said area of directional change for introducing a fluid to be pumped into said transporting means;

said pumping means responsive to said change in the direction of said transporting means whereby a fluid to be pumped is introduced by said pumping means into said transporting means at the said area of directional change and entrained with said pumping means;

said pumping means being a fluid flowing through said transporting means;

said transporting means is a conduit, said conduit having a constant inner radius and a constant outer radius at said area of directional change; and said fluid flowing through said area of directional change in said conduit having a minimum pressure and maximum flow at said constant inner radius and a maximum pressure and a minimal velocity at said constant outer radius.

2. The jet ejector pump of claim 1 wherein said fluid to be pumped is introduced to said conduit at said inner radius and;

said maximum flow is equal to or less than the flow rate of said pumping fluid entering the area of directional change.

3. The jet ejector pump of claim 2 where said fluid to be pumped is introduced parallel to the direction of said fluid flowing through said transporting means where it enters the area of directional change.

4. The jet ejector pump of claim 2 wherein said fluid to be pumped is introduced at an angle greater than zero and less than to the direction of said fluid flowing through said transporting means where it enters the area of directional change.

5. The jet ejector pump of claim 2 wherein said fluid to be pumped is introduced at an angle of 90 to the direction of said fluid flowing through said transporting means where it enters the area of directional change.

Claims

1. A jet ejector pump comprising: a pumping means; means having at least two axes and transporting said pumping means in at least two nonparallel axial directions and being continuous in at least the area of directional change; means at said area of directional change for introducing a fluid to be pumped into said transporting means; said pumping means responsive to said change in the direction of said transporting means whereby a fluid to be pumped is introduced by said pumping means into said transporting means at the said area of directional change and entrained with said pumping means; said pumping means being a fluid flowing through said transporting means; said transporting means is a conduit, said conduit having a constant inner radius and a constant outer radius at said area of directional change; and said fluid flowing through said area of directional change in said conduit having a minimum pressure and maximum flow at said constant inner radius and a maximum pressure and a minimal velocity at said constant outer radius.

2. The jet ejector pump of claim 1 wherein said fluid to be pumped is introduced to said conduit at said inner radius and; said maximum flow is equal to or less than the flow rate of said pumping fluid entering the area of directional change.

4. The jet ejector pump of claim 2 wherein said fluid to be pumped is introduced at an angle greater than zero and less than 90* to the direction of said fluid flowing through said transporting means where it enters the area of directional change.

5. The jet ejector pump of claim 2 wherein said fluid to be pumped is introduced at an angle of 90* to the direction of said fluid flowing through said transporting means where it enters the area of directional change.