US3531218A - Ejector - Google Patents

Description

Sept. 29, A1970 J. l.. WARNER EJEGTOR Filed June 27, 1968 FIG-) 'l'. ulm

A 'l In United States Patent Office 3,531,218 Patented Sept. 29, 1970 3,531,218 EJECTOR John L. Warner, Simsbury, Conn., assigner to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed June 27, 1968, Ser. No. 740,610 Int. Cl. F041? 00, 5 /48 U.S. Cl. 417-183 6 Claims ABSTRACT OF THE DISCLOSURE The areas of the primary and secondary nozzles are concomitantly changed by pivotally mounted flaps extending from the end of a duct supplying the primary uid which is movable from a closed to a full open position while cooperating with the wall of the second passage to define a secondary nozzle, movable to a full closed and opened position.

BACKGROUND OF THE INVENTION This invention relates to ejector pumps and particularly to variable geometry ejector pumps.

As is Iwell known in the art, ejectors are utilized to raise the pressure level of one fluid stream with another higher pressure level stream toz some pressure level intermediate between the two. It isI known to provide ejectors that include variable area primary nozzles but having xed secondary nozzles. Thisv has its shortcomings due to the fact that when there is sufficient pressure and flow through the secondary'nozzle without the need of the primary nozzle, the fixed secondary nozzle offers a resistance to the ow and hence, results in a pressure drop thereacross. In this extreme the ejector loses efficiency and in certain applications, particularly where an aircraft engine is utilized, this results in engine pentalties. This is also true in the other extremity of the pressure range where flow from the secondary nozzle is not required and all the Itlow from the primary nozzle is needed. To this end I have found that these problems can be obviated by opening of the primary nozzle to its full unrestricted area and concomitantly closing the secondary nozzle and vice versa which results in a wider use of the pressure range. Hence, it is possible to obtain greater utilization of the ejector since it is operable over a wider pressure range than the heretofore known types of ejectors. Furthermore at intermediate positions of primary and secondary nozzle opening, more favorable combinations of areas can be achieved again providing greater utilization of the ejector at points other than the design condition.

SUMfMAiRY OF INVENTION BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a view partly in schematic, partly in elevation and partly in section illustrating a preferred embodiment of the present invention.

FIG. 2 is a sectional,view taken along the lines 2 2 of FIG. 1. A

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment is shown in FIGS. 1 and 2 where the ejector generally illustrated by numeral '10 controls the flow of bleed air from the jet engine schematically shown by numeral 12. As is known, it is desirable to bleed pressure from the engine at the lowest stage of the compressor section. But at certain flight conditions, the lower stages are not capable of supplying suii'icient pressure. Hence, the higher stages of the compressor are then bled olf to fuliill the demand.

Hence, in accordance with this invention the ejector comprises a primary nozzle 16 connected to the hi-stage bleed via line 14 and a secondary nozzle 18 via line `20 both nozzles being disposed within sections of pipes 22 and 24, respectively and both sections being rectangular in cross section.

A pair of flaps 26` are pivotally mounted to the downstream end of pipe 22. The adjacent Wall of pipe 24 is also reduced and purposely shaped to define with the back side of flaps 26 an efficient nozzle. Suitable linkage is attached in any suitable manner to the flaps and is connected to a suitable actuator shown in blank box 30 by link 32.

In the position shown, the primary nozzle is closed and the secondary nozzle 10` is wide open such that no restriction to the flow is imposed resulting in no pressure drop. The flaps are movable to an unrestricted flow position of the primary nozzles as shown by the dash lines to accommodate a blockage of `flow from the secondary nozzles. In the immediate positions of aps 26, the flow from the primary nozzles induces flow from the secondary nozzles and functions as a typical ejector. In this manner the flaps serve as a means for obtaining the characteristics of an ejector while obtaining full unrestricted flow from either the primary or secondary nozzles.

A check valve 36 disposed in line 20 assures that flow from the hi-stage bleed doesnt divert back to the engine.

It has been found that in certain air-conditioning systems for aircraft the precooler utilized to cool the bleed air before admittance to the main heat removal system can be eliminated by use of the present invention. In the preferred embodiment the discharge bleed air controlled by the ejector 10 is delivered to a suitable air-conditioning system (not shown).

In this embodiment preferably the ejector would be operated as a function of the air-conditioning system requirements. A suitable controller shown in blank and illustrated by numeral 3'8` would sense these pressures and control actuator 30. A shut-olf valve 40y actuated by suitable actuator 42 may be employed to shut-olf the hi-stage bleed at certain conditions. A temperature sensor 44 may also be employed to limit the temperature downstream of ejector 10.

It should be understood that the invention is not limited to the particular embodiments shown and described herein, but that various changes and modifications may be made without departing from the spirit or scope of this novel concept as defined by the following claims.

I claim:

1. An ejector having a primary nozzle and a secondary nozzle, means for concomitantly varying the area of the primary nozzle and the area of the secondary nozzle, and said primary nozzle and said secondary nozzle are movable to opened and closed positions and when fully opened said primary and secondary nozzles impose substantially no pressure losses to the fluid passing therethrough when in the full opened position.

2. An ejector comprising, in combination:

a secondary nozzle;

duct means connecting said secondary nozzle to a low pressure source;

a primary nozzle in said duct means;

additional duct means connecting said primary nozzle to a pressure source relatively higher than said low pressure source;

a movable member attached to one of said duct means simultaneously varying the area of said primary and secondary nozzles such that when said nozzles are in the full opened position substantially no pressure loss will be incurred thereby, and

said movable member being movable to close either said primary nozzle or said secondary nozzle.

3. An ejector as claimed in claim 2 wherein said movable member defines with the wall of said duct means a secondary nozzle.

4. An ejector as claimed in claim 2 wherein said movable member is mounted on said additional duct means to deliue a primary nozzle.

'5. An ejector as claimed in claim 4 wherein said movable member includes a pair of complementary symmetrical elements pivotally mounted at the end of said additional duct and movable to block off ow therefrom.

6. An ejector in combination with a jet engine having stages of compression comprising:

a rst duct having connection means to a lower stage of said stages of compression;

a second duct having a portion disposed in said first duct and having connection means to a higher stage of said stage of compression;

movable means defining primary and secondary nozzles and concomitantly changing the areas of said nozzles; and

means for positioning said movable means from a full open to a full closed position such that ow through said secondary nozzle passes without any substantial pressure losses when said means fully opens said secondary nozzle and ow through said primary nozzle passes without any substantial pressure losses when said means fully opens said primary nozzle.

References Cited UNITED STATES PATENTS MARK NEWMAN, Primary Examiner W. J. KRAUSS, Assistant Examiner U.S. Cl. X.R. 417-185

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