US2842159A - Injector valve - Google Patents

Description

w. l. SPRAGUE July 8, 1958 INJECTOR VALVE Filed Feb. 25, 1955 r E *mmm Q l om v m. l mv om a. Nm

E s lll Nv NN .l www 1l| fav-@m RNE@ United States Patent INJECTOR VALVE Wesley I. Sprague, Davenport, Iowa, assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application February 23, 1955, Serial No. 490,014

3 Claims. (Cl. IS7-513.7)

This invention relates to injectors of the type in which a jet of iluid propelled into a passage past an opening draws another fluid through the opening into the passage. It has been found especially suitable for use in oxygen regulators which supply oxygen mixed with varying proportions of air, for example, to breathing masks of high altitude aviators. In certain types of such regulators the oxygen under pressure passes through an injector in which it entrains air, forming a mixture of air and oxygen for breathing. The quantity of oxygen required by the aviator, and the correct proportion of oxygen to air, both vary with changes in altitude, requiring an arrangement which provides for changing these factors as the altitude changes.

It has been found that previous injector arrangements for this purpose have not maintained the correc-t airoxygen ratio, as the rate of oxygen supply was varied in accordance with altitude changes, to the degree of accuracy that is desirable. An object of the invention is to provide an injector arrangement that will produce with greater accuracy the correct proportions 4and quantities of entraining and entrained fluids respectively as the rategof supply of the entraining lluid varies.

This rate of supply is generally adjusted by varying the pressure at which the entraining uid, which is oxygen in the specific example used herein, is supplied to the injector. With known types of injector nozzles it has been found that variations in the supply pressure, while they vary the amount of entraining fluid discharged from the nozzle, kdo not produce the entrainment of a properly varied amount of the entrained uid. A further object of the invention is therefore to provide a nozzle struc` ture that will be aifected by variations in uid supply pressure so as to produce a variable jet of such character that the rate of entrainment will befimproved. This is in general accomplished in accordance with the present invention by providing a supplementary nozzle structure. A purpose of the invention is to provide such a structure in an effective for-m, and in particular to provide an arrangement for varying the action of such structure in accordance with variations in the supply pressure of the entraining fluid, such as oxygen.

The invention is especially adapted for use with injectors provided with a fixed nozzle, the rate of discharge from which varies with variations in the rateof the supply pressure. A purpose of the invention is to provide a supplemental nozzle that will coact with the fixed nozzle to produce the results indicated. In the preferred form the supplemental nozzle structure is annular and concentric with the fixed nozzle, having a coaxial discharge opening. A purpose of the invention is to provide means for discharging through the supplemental nozzle an amount of entraining lluid which varies with the pressure. A related object is to employ such pressure to vary the amount of fluid discharged through ya supplemental nozzle and to vary the position of the latter noza lCC zle for this purpose in accordance with variations in said pressure.

The preferred arrangement for this purpose involves the connection of the supplemental nozzle structure to a piston arrangement biased against the entraining Huid pressure. A specific feature is to arrange a biasing spring engaging the piston structure in yieldable opposition to said iuid pressure. A related object is to utilize a fixed nozzle to provide a sealing seat for the supplemental nozzle, with the latter biased toward the seat.

It has been found that under certain circumstances the volume and proportions of the fluid mixture vary satisfactorily up to a certain entraining fluid supply pressure. An object of the invention is to provide a primary nozzle structure that will be operative up to the latter pressure, and a supplemental nozzle structure through which supplemental fluid'will be injected when `the supply pressure rises above the indicated value. A

more speciiic object is to provide an arrangement in which the annular piston-controlled supplemental nozzle is held against a sealing seat up to a selected entraining fiuid pressure, above which it is progressively moved away from such seat by said pressure to provide a correspondingly increased entraining uid ilow. A related object is to provide means for adjusting the minimum pressure at which uid will pass through the supplemental nozzle.

While the invention is especially advantageous for injectors provided with supplemental nozzles, it includes features that are not limited to such structures. An object of the invention is to provide an improved owregulating arrangement of the indicated type that is suitable for use with single nozzle injectors. Moreover, one embodiment of the invention is adapted for use as a relief blow-olf for pressure-opening valve. An object, therefore, is to provide a novel structure that may be used for these purposes; and a related object is to provide a structure that may be used either as a pressureopening valve or as a nozzle.

Other objects are to provide aneiective sealing seat for the xed nozzle and the supplemental nozzle structures, to provide an ecient seal for the piston arrangement, to dampen the tendency of the injector to chatter, and to accomplish any or all of the above mentioned objects by means of a structure that is relatively simple and practical, compact, durable, and adapted for use in standard apparatus employing injectors, such as oxygen regulators.

The foregoing and other objects andadvantages of the invention will appear more fully from consideration of the detailed description which follows, in conjunction with the accompanying drawing wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawing is for the purposes of illustration and description and is not to be construed as defining the limits of the invention. In the drawing:

Fig. 1 is a longitudinal central section through an embodiment of the invention operating as an injector, showing the fixed nozzle open and the supplemental nozzle in closed inactive position; and

Fig. 2 is a similar View with the supplemental nozzle open and in operation.

The illustrated embodiment is of the type suitable for use in oxygen regulators, one form of regulator of this type being illustrated in U. S. Patent No. 2,630,817, Pauly et al., issued March l0, 1953. The regulator includes a body 10, which may form part of the main regulator body and is provided with a cylindrical bore 11 into -which the injector housing cylinder 1-2 tits. The fixed injector 13 comprises a retaining block 14 fitting within cylinder 12 and provided with an annular flange 1'5 bearing against the feed end of cylinder 12 and fitting in bore 11. A sealing ring 16 is located between flange 15 and shoulder 17 on the body 10. The nozzle structure assembled in housing cylinder 12 is held in place in said body by a discharge pipe 18 having its inner end 19 threaded into the bore 11 and bearing against the discharge end of cylinder 12, pressing fiange 15 and ring 16 against shoulder 17 and locking cylinder 12 in place.

The fixed injector 13 comprises a fixed nozzle 2) in'- cluding a cylindrical body 21 axially threaded into block 14, provided with a feed passage 2.2 and having a tapered tip 23 through which extends an axial discharge passage 24 substantially smaller than feed passage22.

The supplemental nozzle 25 comprises a generally cylindrical body 26 slidably fitting in housing cylinder 12 and provided with a supplemental feed passage 27 terminating in a reduced end portion of body 26. The frustoconical wall 28 of said end portion has a slightly wider angle than the frusta-conical wall 29 of tapered tip 23, converging toward the latter and arranged to contact said tip only in a zone 28a immediately adjacent the outer end thereof, in which the two walls 2S and 29 may have the same taper and fit flat against each other throughout said zone. The end wall 30 of body 26 forms an acute angle with wall 28, and zone 28a, to produce a thin plate orifice 31 whose diameter is not less than that of passage 24, and advantageously is slightly greater. Wall 30 may comprise an annular inner zone 32 substantially normal to the axis of discharge passage 24, and an outer zone 33 sloping slightly in the direction of discharge relative to the inner zone 32.

Spring means is provided for biasing the supplemental nozzle 25 toward the fixed nozzle 20; and a seal is also advantageously provided between sliding nozzle 25 and the inner wall of housig cylinder 12 to prevent leakage of oxygen past nozzle 25 along the latter wall. In the arrangement illustrated, an O-ring 34 of resilient material such as rubber is seated in annular recess 35 in the outer face of the supplemental nozzle 25; and a spiral compression spring 36 extends along the inner face of cylinder 12, around a reduced section 37 of nozzle 25' and bears against the O-ring 34 at one end of the spring, the other end of which bears against shoulder 38 formed at the abutting face of pipe end 19.

With this arrangement the portion of housing cylinder 12 beyond the valve structure forms a mixing chamber 39; and an air inlet arrangement connected to this chamber is provided. In the form illustrated this inlet comprises a cylindrical inlet passage 40 formed in the body and extending through a registering opening in cylinder 12. The discharge pipe 18 provides a discharge passage 41 from said chamber.

1In operation, oxygen introduced through feed passage 22 is discharged through passage 24 into mixing chamber 39, where it entrains air from passage 40 and the mixture is discharged through passage 41. During initial operation at lower pressures the supplemental nozzle 25 is held tightly against the xed nozzle 20 in zone 28a to seal passage 27, so that all of the oxygen travels through passage 24. Nozzle body 21 is provided with openings 42 connecting the feed passage 22 with piston chamber 43 between body 21 and the inner wall of cylinder 12 and in communication with passage 27, so that oxygen under pressure builds up in the chamber 43. However, spring 36 initially holds the nozzle 25 in seated position against fixed nozzle 20, preventing any material escape of oxygen between the nozzles; and O-ring 34 under spring pressure prevents leakage around nozzle 2S. However, as the feed pressure builds up, it finally overcomes the spring pressure and the friction of the O- ring 34 and shifts supplemental nozzle 25 endwise so that oxygen is discharged not only through passage 24 of the fixed nozzle 20 but also around-said nozzle through. passage 27 and orifice 31 of the supplemental nozzle 25, the amount of oxygen traveling through this passage being dependent upon the feed pressure. The latter amount will of course vary with the pressure, being increased as the pressure increases, and vice versa; and the thin plate character of orice 31 will produce a clean jet with a minimum of turbulence in mixing chamber 39, thereby assuring the proper entraiment of air from passage 46. The air and oxygen combine in chamber 39 and the mixture is discharged through passage 41.

The nozzle structure is arranged so that the pressure at which the supplemental nozzle 25 opens can be adjusted by screwing the nozzle 20 to right or left in retaining block 14, thereby varying the compression of spring 36. The same adjustment may be used to change the position of the outlet end of passage 24 relative to the air inlet passage 40, thereby obtaining the best location for maximum uniform entrainment of air.

The disclosed construction is arranged for eflcient and economical manufacture and assembly, the parts being inserted successively from the right of Fig. l and held in position by screwing pipe 18 into place. lt has been found in practice that with this arrangement the desired uniform maintenance of the proper proportion between oxygen and air, and the desired rate of 'flow of the mixture, are maintained throughout a wide range of rates of oxygen supply, with corresponding changes in feed pressure and in the relative proportions of air entrained by the oxygen.

While the invention is particularly advantageous in connection with a double nozzle injector valve structure as described, it is also suitable for use in similar structures for other purposes. For instance, by closing the discharge passage 24 of fixed nozzle 20 in suitable manner the device is adapted for use as a relief valve, for which purpose the air inlet 40 will of course be unnecessary. For this purpose the spring 36 is designed and arranged to apply suitable pressure to the supplemental nozzle structure 25, so that the latter, analogous in this instance to a valve head, will lift when the pressure of the fluid supplied to passage 22 rises above the selected relief value.

This arrangement may also function as a variable flow nozzle, which may be used as an injector in the manner described. ln this instance the entire fluid flow travels through passage 27 and orifice 31, the size of the passage and consequently the rate of flow varying in accordance with pressure. When designed for this type of operation, spring 36 may be arranged either to allow nozzle 25 to open when any appreciable pressure is applied to the fluid in passage 22, or to open at a predetermined minimum pressure as already described.

For these uses provision is made for closing passage 24 or the adjacent portion of passage 22. This may be accomplished in various ways. In the form illustrated, butterfly valve 44 is pivoted in body 21 of the fixed nozzle and proportioned to close passage 22 beyond openings 42, or to leave said passage fully or partly opened, in accordance with the setting of valve 44. The latter valve is advantageously mounted under sufficient friction so that it will maintain in operation the position at which it is initially set.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the parts Without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

I claim:

1. An injector comprising a housing provided with a bore, a pressure chamber in said bore connected to a source of fluid supply under pressure, a nozzle structure including a nozzle element provided with a tapered end terminating in a fiuid discharge aperture and slidably fitting in said bore, a stationary closing member for said discharge aperture carried by the housing and including an elongated body having a tapered end coaxial with said aperture, said closing member having a coaxial passage communicating with the pressure chamber and the tapered end terminating in said aperture and registering 'with the tapered end of the nozzle element to form a closure seal when said ends are in contact, and means for yieldably biasing said nozzle element toward the closure member to bring said ends into contact, said nozzle ele ment being yieldable under fluid pressure to permit iluid from said chamber to pass through said aperture at a rate varying with the displacement of the nozzle element by fluid pressure.

2. An injector comprising a housing provided with a bore, a pressure chamber in said bore connected to aA source of uid supply under pressure, a nozzle structure including a nozzle element fitting in said bore located at one side of the pressure chamber and provided with a jet-producing fluid discharge aperture, an inlet for entrained uid adjacent to the path of the jet, a stationary closing member for said discharge aperture carried by the housing, means yieldably biasing the nozzle element toward and against the closing member against uid pressure in said chamber, arranged to yield under predetermined fluid pressure to move the nozzle element away from the closed position and increase flow through the nozzle in accordance with increases in uid pressure, and means including an annular member of yielding resilient material carried by the nozzle element in continuous engagement with said element and the adjacent face of the bore, for providing a seal and damping vibrations of said element.

3. An injector as claimed in claim 2 in which the biasing means is a spiral compression spring bearing against and compressing the annular resilient member.

References Cited in the le of this patent UNITED STATES PATENTS 333,651 Matthews Ian. 5, 1925 1,539,271 Pokorny May 26, 1925 1,900,514 McLean Mar. 7, 1933 2,406,178 Walley Aug. 20, 1946 2,645,242 Monnch Iuly 14, 1953 2,755,246 Whitlock July 17, 1956 l FOREIGN PATENTS 785,809 France May 27, 1935 872,910 Germany Apr. 13, 1953

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