US2918009A - Injection-compressor apparatus - Google Patents

Description

' Dec. 22,1959 M; CREVOISIER 2,918,009

INJECTION-COMPRESSOR APPARATUS 4 Sheets-Sheet 1 I 211 fa Filed Jan. 2a, 1958 Dec. 22, 1959 Filed Jan. 28, 1958 4 Sheets-Sheet 2 w mQ m QE

1959 M. CREVOISIER INJECTION-COMPRESSOR APPARATUS 4 Sheets-Sheet 3 Filed Jan. 28, 1958 1959 M. CREVOISIER 2,918,009

INJECTION-C OMPRESSOR APPARATUS Filed Jan. 28, 1958 4 Sheets-Sheet 4 r" A 2,918,009 Ice Patented Dec. 22, 1959 2,918,009 INJECTION-COMPRESSOR APPARATUS Marcel Crevoisier, Paris, France, assignor to Societe Nouvelle Dieny & Lucas, Paris, France, a French society Application January 28, 1958, Serial No. 711,727

Claims priority, application France February 1, 1957 8 Claims. (Cl. 103-7) This invention relates to fluid compressors or pumps of the type wherein. auxiliary inlet means are provided for injecting into the main or primary stream of fluid being. compressed, an additional or secondary fluid required to be intimately mixed and compressed with the main fluid. y

In the past such devices have had only limited application-to situations wherein the secondary fiuid injected into the main fluid stream was sometimes a coolant fluid and sometimes a lubricating fluid, such as oil. It is a general object of this invention to extend the range of usefulness of injection-compressors of the specified type by the provision of novel and improved features therein whereby such apparatus will be applicable to many fields inwhich the use of such apparatus was notheretofore feasible.

The injection-compressors or pumps contemplated herein are of the vane-type generally comprising a stator or body with a cylindrical chamber having inlet and outlet means for the main fluid connected therewith, and a rotor mounted in excentric relation within the chamber and having a set of slidable vanes projecting in. a generally radial direction from the rotor periphery into engagement with the wall of the stator chamber so that, on rotation of the rotor, the vanes will sweep the fluid from said inlet to said outlet while simultaneously compressing said fluid owing to the separate fluid-tight compartments of decreasing capacity defined between adjacent vanes. One or more secondary inlet orifices are formed in an end wall of the stator chamber and a slot or aperture is provided in the periphery of the rotor at a suit able point between two adjacent vanes thereof and is adapted, during each revolution of the rotor, to register with said secondary inlet to inject secondary fluid into the stream of primary fluid undergoing compression.

It is an object of this invention to provide improved apparatus for mixing two or more fluids in accurately metered proportions and to compress the resulting mixture. It is a related object to provide a novel and improved injection-compressor system particularly useful in connection with the supplying of fuel to internal combustion engines.

In accomplishing the above objects of my invention I provide improved means, in an injection-compressor of the type described, for accurately and smoothly adjusting the effective cross-sectional area of the secondary fluid inlet means. A related object which my invention accomplishes is the provision of such adjusting means which can conveniently and efficiently be operated automatically by means of a servo-system of any appropriate kind.

In conventional injection-compressors it is generally necessary to reduce the output pressure of the compressor below the nominal value that is attainable therewith in order to make a predetermined amount of negative pressure available within the compressor for eifectively drawing-in the secondary fluid. It is also an objectof the invention to eliminate this objectionable limitation and make it possible to operate an injection-com"- pressor at full nominal pressure while still providing for efficient injection of the secondary fluid. With this object in view my invention may provide (as known per se) a recess in the wall of the stator chamber adjacent the primary or main fluid inlet in order to ensure that each rotor compartment is properly filled with the main or primary fluid as it sweeps past said inlet, but such recess, in accordance with the invention, is of reduced circum ferential extent so as to define a zone of vacuum sealed off from the main fluid inlet, and an outlet and the secondary fluid inlet means are position in that vacuum zone. In this way the negative pressure is held at a uniform value regardless of the rate at which the primary fluid is pumped, and hence the secondary fluid is injected under conditions that do not depend on the rate of delivery of the compressor.

The above, and further objects, features and advantages of the invention, will appear in the following detailed description of embodiments thereof, given for pur-- poses of illustration but not of limitation, with reference to the accompanying drawings wherein:

Fig. l is an axial sectional view of a first embodiment.

Fig. 2 is a sectional view on line II-II of Fig. 1.

Fig. 3 is a detail section through a flange of the compressor, on line IIIIII of Fig. 1.

Fig. 4 is a fragmentary elevational view of the compressor flange shown in section of Fig. 3. p Fig. 5 is a transverse sectional view on line V-V of Fig. 6, and showing another embodiment of a compressor according to the invention.

Fig. 6 is an axial sectional view of the secondary inlet control arrangement in the embodiment of the invention shown in Fig. 5.

Fig. 7 is a sectional view of an arrangement for controlling the cross-sectional area of a secondary inlet in a third embodiment of the invention.

Fig. 8 is a section on line VIII-VIII of Fig. 7.

Fig. 9 is a cross sectional view generally similar to that of Fig. 2, but illustrating another feature of the invention.

Fig.- 10 is a cross sectional view generally similar to that of Fig. 1, but illustrating still another embodiment of the invention.

. Fig. 11 is a sectional view taken along the line XI-XI of Fig. 10.

. Referring first to Figs. 14, it will be seen that the vane-type pump or compressor there illustrated comprises a stator assembly made up of spaced flanges 1a and 1b retained in assembled relationship by an intermediate spaced member 2 which is formed with a cylindrical recess 3 therein. Rotatably mounted in the stator, assembly is a shaft 5 which is olf center with respect to the recess 3 and is journalled in the flanges 1a and 1b. Secured on shaft 5 is a cylindrical rotor member 4 which is coaxial with the shaft and arranged to be substantially tangent with the wall of recess 3 at one point, the lowermost point of said recess as shown in the drawings. Formed in the rotor member 4 are a plurality of slots in which vanes 6 are slidable. While the slots and vanes might extend radially with respect, to the rotor, and

such an arrangement, is shown in Fig. 9 later described, in the embodiment now being described the slots and the vanes are directed angularly as shown. An inlet for primary fluid, e.g. air, is provided in spacer member 2 at 7 for connection with a source of the fluid, and an outlet 8' is provided in spacer member 2 and is connectable with equipment in which the compressed fluid mixture is to' be utilized. The rotor 4 is assumed to be rotatably drivenin the counterclockwise direction, as viewed in Fig. 2, as indicated by the arrow 9. I

A cylindrical metering chamber 12is formed. in the. stator flange 1a in a direction normal to the axis of rotor rotation and is connected at one side, through duct 16 the primary fluid inlet 7, considered in the direction of rotor rotation. A slot (Fig. 2) is cut in a point of the periphery of the rotor 4 to register with the orifices 11 during every revolution of the rotor. As will be later described, the recess 18 is adapted, during operation of the system, to be filled with secondary fluid which is to be injected into the primary fluid through bore 12 and inlet orifices 11.

Y The metering chamber 12 has means therein for ad justing the total efiective cross-sectional area of the secondary inlet orifices 11. In the embodiment being described, said adjusting means comprises a plunger 13 fitting closely in the cylindrical chamber 12 and adjustable therein by means of a set screw 14 acting in opposition to a spring 15 so as to uncover a desired number of the orifices 11.

' Secured with screws to the outer side of flange 1a and extending over the recess 18 is a two-part valve casing 17, and a flexible diaphragm 19 is clamped across the recess 18 between the periphery of the casing 17 and the flange, so as to define a chamber 26 in the valve casing. The chamber 26 is connected by way of a duct 28 with an inlet 27 formed in the flange 1a and connectable with a source of secondary fluid, e.g. liquid fuel. Secured centrally of the diaphragm 19 is a valve element 20 having an axial bore 21 and seatable against a seat 22 supported in a bushing member 24 screwed into the center of the outer part of casing 17. Radial ducts 25 extend through the sides of the bushing member 24. A spring 23 tends to apply the valve element 20 against its seat 22. In this seated condition it will be seen that the recess 18 communicating with the metering chamber 12, is sealed off from the outer chamber 26 which communicates with the inlet 27 and is at all times filled with secondary fluid.

In operation, rotation of the rotor 4 in the counterclockwise direction, as viewed in Fig. 2, results in drawing primary fluid into chamber 3 through the inlet 7 and compressing it in the compartments defined between the successive vanes 6 while said fluid is swept towards and into the discharge outlet 8. As the slot 10 is brought into registry with those orifices 11 which are uncovered by the plunger 13, a negative pressure is communicated by way of said orifices to the recess 18 so that thedia phragm 19 and valve element 29 are drawn leftward (as viewed in Fig. 1), thereby establishing communication between recess 18 and the outer chamber 26 whereby secondary fluid is drawn into chamber 12 by way of ducts 25, axial bore 21, recess 18 and duct 16 and an accurately metered amount of this fluid is drawn from chamber 12 into chamber 3 through orifices 11 every time said orifices are uncovered by the slot 16 in the rotor. This secondary fluid is then intimately mixed with the primary fluid undergoing compression within the rotor compartment in which the slot 10 is provided. Therefore, a compressed mixture of primary'and secondary fluid in accurately predetermined proportions is discharged by way of outlet 8.

In the embodiment partly illustrated in Figs. 5 and 6, the plunger-type metering device formed by the plunger 13 of the first described embodiment is replaced by a rotatable disc-type metering device which includes a disc 29 formed with an arcuate cutout 30 adapted to uncover a variable number of the orifices 11. The disc 29 is rotatable in the flange 1a about an axis parallel tothe rotor axis. An actuating rod 31 projecting axially from the disc 29 is operable manually or mechanically for adjusting the total effective cross-sectional area of the orifices. As shown, rod 31 is journaled in a bushing 32 which is screwed in an outer bushing 33 screwed in turn into a bore of the flange 1a, and a spring 34 acts I 37a into the stator chamber.

between the disc 29 and a dual sealing assembly including washers 35 and an intermediate seal 36, for applying the disc 29 against the orifices. The chamber defined at the right of the disc 29, as viewed in Fig. 6, is herein connected, by way of the duct 12, with the recess 18 and remaining structure for admitting secondary fluid which structure may be similar to that shown in Figs. 1 to 4.

In Figs. 7 and 8, the means for adjusting the total eflective cross-sectional area of the orifices 11 comprises a valve member 37 rotatable in a bore 37a formed in flange 1a normal to the rotor axis as in the first embodiment described, with the orifices 11 opening from bore The inner end of bore 37a communicates with the duct 12 for admitting the secondary fluid and the rotatable valve member 37 is hollow and is slotted at 38 so as to uncover a variable number of the orifices 11 disposed in a row at an angle to the axis of the valve member 37. The uncovered orifices 11 communicate with the duct or bore 12 by way of the slot 38 and hollow interior of valve member 37. An operating shank 39 secured to member 37 is journalled in a guide bushing 40 screwed in the flange 1a. A spring 41 acting between bushing 40 and a spring seat 42 applied against member 37 through a seal ring 43 biasses the valve member toward the right, as viewed in Fig. 7. Shank 39 may be actuated manually or mechanically.

Fig. 9 illustrates another advantageous feature of the invention. As there shown a recess 44 is formed in the cylindrical wall of the stator chamber adjacent to the primary inlet 7. Such a recess is also shown to be present in the embodiment of Fig. 1, and its primary purpose is to provide an extended area filled with primary fluid in contact with the rotor so as to facilitate the filling of each rotor compartment as it sweeps past the inlet. However, it will be noted that in Fig. 9 the angular extent of recess 44 is substantially smaller than the angular extent of each rotor compartment, e.g. recess 44 may have an extent of 30 where the rotor compartments are 60 in extent as shown. In this way there is provided a zone 45 which is at no time in communication with the inlet 7 or with the outlet. The secondary inlet orifices 11 are formed in this zone 45. Since the degree of negative pressure obtained in the zone 45 remains substantially constant at all times during rotation of the rotor regardless of the volume of fluid it will be seen that the amount of secondary fluid drawn in can be made substantially independent of the rate of delivery of the primary fluid.

In the embodiment illustrated in Figs. 10 and 11, the rotor is formed with radial slots 10 and 10a at the peripheries of its opposite side walls. The flange 1a has orifices 11 therein cooperating with slot 10, as in the previous described embodiments. Moreover, the flange 1b has orifices 11a formed in the path of the slot 10a and which communicate with a conduit 12a formed in the flange 1b in a direction normal to the rotor axis.

Moreover, the rotor 4- has a bent conduit 46 extending through it, said conduit opening at one end into the suction zone of the compressor and, at its other end, at the side wall of the rotor opposite the flange 1b. Said flange 1b has orifices 11b formed in it, which are located in the path of the end of the conduit 46 opening at the side surface of rotor 4, and which communicate with a conduit 12b parallel to the conduit 12a.

Conduits 12a and 1212 are arranged in the same manner as the conduit 12, i.e. each conduit communicates with a source of auxiliary fluid through a conduit 16a or 16b respectively, and they are provided with means for metering or varying the total eflective cross-sectional area of the orifices 11a or 11b.

Said metering means may comprise for example'the plunger 13 of the embodiment of Figs. 1-4 or the rotatable valve member 37 of the embodiment of Figs. 8 and 9. In the embodiment of Fig. 11 a micrometric plunger 47 has been provided which is slidably mounted in each of the conduits 12a or 12b and has a radially opening, longitudinally extending groove 48 adapted to receive a finger or set screw 49 screwed in the flange 1b. The plunger 47 is thus prevented from rotating within the conduit. The plunger 47 has secured to it a threaded member 50 which is screwed in a plug or cap member which is also threaded externally and is screwed in the conduit 12a or 12b. The internal and external threadings of the cap 51 are slightly different so that on. screwing said cap into the conduit, the member 50 of the plunger 47 will be displaced longitudinally by a distance which is a function of the difference in pitch of the cap threadings.

In the embodiment of Figs. and 11, it is possible to inject into the main compressed fluid, three different auxiliary or secondary fluids, the rates of flow of the fluids delivered through the conduits 12a and 12b being regulated by means of the related caps 51.

It is found that an injection-compressor embodying the improvements of my invention is suitable for many useful purposes. Thus, in combustion-engine fuel supply systems the novel apparatus may be used for mixing combustion air, serving as the primary fluid, with liquid fuel constituting the secondary fluid. The resulting combustible mixture has extremely desirable combustion characteristics in view of the intimate mixing obtained and furthermore it is inherently pre-heated owing to the temperature elevation generated by the compression. Liquid fuels of comparatively high viscosity, e.g. an Engler viscosity of 7 at 20 C., have been successfully used in a fuel supply system embodying the injectioncompressor of the invention.

Further advantageous uses of the novel injection-compressor is in the mixing and compression of spray-paint mixtures for use in spray-guns and the like, and also in refrigeration systems where the primary fluid is the gaseous cooling medium and the injected secondary fluid is the same medium in liquefied form.

The above applications of the injection-compressors embodying the invention are not exhaustive since many additional useful applications can be found in various fields of engineering wherever a mixture of two or more fluids in accurately predetermined proportions and at superatrnospherie pressure is required.

What I claim is:

1. Apparatus for providing a mixture of at least two fluids in metered proportions and under pressure com prising a stator having spaced apart side walls and a cylindrical wall extending between said side walls to define a stator chamber, said stator further having an inlet and an outlet for a primary fluid which open into said stator chamber at circumferentially spaced apart locations, a rotor rotatable in said stator chamber about an axis which is eccentric with respect to said cylindrical wall and fitting closely against said side walls, vanes slidably projecting from the periphery of said rotor into engagement with said cylindrical wall so that separate compartments of varying capacity are defined between the successive vanes to displace primary fluid from said inlet to said outlet while simultaneously compressing the fluid in response to rotation of the rotor, at least one metering chamber in said stator, means for connecting said metering chamber to a source of a secondary fluid,

said stator having at least one series of orifices opening from said metering chamber into said stator chamber at one of said side walls of the latter and being arranged along a substantially arcuate line which is radially inside the periphery of said rotor, said rotor having at least one peripheral cutout opening radially into one of said compartments and also opening against said one side wall of the stator chamber to successively register with said orifices during each revolution of said rotor, and a valve member in said metering chamber being displaceable to open and close said orifices successively, thereby to vary the total eflective cross-sectional area of said orifices.

2. Apparatus as in claim 1; wherein said metering chamber has a cylindrical portion arranged with its axis parallel to the axis of said stator chamber and with a flat radial face through which said orifices open; and wherein said valve member is in the form of a circular disc urged axially against said flat radial face and having a peripheral cutout for uncovering said orifices successively upon turning of said disc.

3. Apparatus as in claim 1; wherein said metering chamber is cylindrical and arranged with its axis normal to the axis of said stator chamber, said orifies opening from the cylindrical surface of said metering chamber.

4. Apparatus as in claim 3; wherein said valve member is in the form of a cylindrical plunger movable axially in said metering chamber, and said orifices are spaced apart along the metering chamber to be progressively covered and uncovered in response to axial movement of said plunger.

5. Apparatus as in claim 3; wherein said valve member is in the form of a hollow cylindrical body rotatable in said metering chamber and having a slot extending over a portion of the periphery of said body, and said orifices are spaced in the circumferential direction of said cylindrical surface of said metering chamber so that said slot of the cylindrical body progressively uncovers the orifices upon rotation of said hollow cylindrical body.

6. Apparatus as in claim 1; wherein said stator has at least two metering chambers opening into said stator chamber through respective series of orifices in said opposite side walls of the stator chamber.

7. Apparatus as in claim 1; wherein said cylindrical wall of the stator chamber has an arcuate recess therein connected with said inlet and having an angular extent which is related to the angular extent of said compartments so that said arcuate recess is always out of communication with said orifices.

8. Apparatus as in claim 1; wherein said means for connecting said metering chamber to a source of secondary fluid includes means for conducting the secondary fluid to said metering chamber and having a shut-off valve interposed therein and spring urged to a closed position, and means responsive to a reduced pressure in said metering chamber upon rotation of said rotor to open said shutoff valve and permit the entry of the secondary fluid into said metering chamber.

References Cited in the file of this patent UNITED STATES PATENTS

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