US1943234A - Liquid and gas spray pump - Google Patents

Description

Jan. 9, 1934- w 13 (:ARTER 1,943,234

LIQUID AND GAS SPRAY PUMP Filed May 6, 1930 3 Sheets-Sheet 1 INVENTOR:

Jan. 9, 1934. w. D. CARTER LIQUID AND GAS SPRAY PUMP Filed May 6, 1930 3 Sheets-Sheet 2 INVENTOR Jan. 9, w CARTER 1,943,234

LIQUID AND GAS SPRAY PUMP Filed May 6, 1930 3 Sheets-Sheet 3 Fig. 8.

Fig. 5.

61 I8 2 27 i I rfingza 33 &

INVEN TOR Patented 1.... 9, 1934 UNITED STATE-S PATENT OFFICE 28 Claims.

This invention relates to that class of pumps described in my co-pendi-ng applications, Serial No. 91,712, now Patent No. 1,703,218 :of Feb. 26, 1929, and Serial No. 207,707, wherein several completely independent streams of fluid are pumped simultaneously, although it also embodies novel pumping means which may be employed to advantage in single-stream pumps.

The full combination is best illustrated in its application as a spray-pump for oil burner service, wherein a uniform amount of oil is maintained in the pump casing to provide the liquid seal and lubrication for the several independent pumping means as well as for supplying oil to be mixed with the air for atomizing or spraying into a furnace.

The general object of this invention is to obtain aquiet, compact pump capable of creating a high oil suction and positive 011 return pressure.

Another object is to devise a simple type of positive displacement plunger pump.

Another object is to provide automatic regulation of the eccentricity in order to control the pumping of liquid and air.

Another object is to make the feeding of liquid to the air completely independent of any variations in the pressures under which the other several pumping units may be operating.

Another object is to provide a combination thrust collar and valve plate whereby thorough lubrication and close fitting valve faces are maintained.

Still another object is to prevent splashing of liquid from "the casing by placing all stationary scoops on the lower side of the impeller and providing novel connecting passages thereto.

These and other objects are attained by the combination of parts illustrated in the accompanying drawings in which Fig. 1 is a vertical cross section of my spray pump taken on line 11 of Fig. 2, and illustrating the several co-operating pumping elements.

Fig. 2 is a top view of pump with cover removed, looking into the pump casing and showing a crosssection taken on line 2-2 of Fig. 1, except .to a

' pearance of the unit as a whole.

Fig. 6 is aside elevation of the distributor with the stem or axle upon which the impeller rotates.

Fig. 7 is a perspective view showing one side and the top of the impeller.

Fig. 8 is a diagrammatical horizontal section of the impeller and casing showing the action of a given discharge, plunger in relation to the casing and impeller, at four difierent positions during each .revolution of the impeller.

Referring now to the drawings in detail: 4 is a stationary distributor member containing various ports and communicating passages for conveying the several independent streams of fluid to and from the impeller 5. Impeller 5 is rotatably mounted on the stationary hollow axle 6 which is closed at its lower end and fixed at its upper open end to distributor 4. 7 is a bowl or casing fastened as by the set-screw 8 to the vertical shaft 9 of motor 10. The spring coupling 11 is pivotally attached at one end 12 to the casing 7, and at the other end 13 to the plunger 14 whereby rotation :is imparted from the casing through the plunger, to the impeller as hereinafter explained. The cover 15 is fastened by means of screws 16 to the casing so as to make a liquid tight joint with the casing. The central opening .17 in the cover allows distributor 4 to extend through to its point of attachment in the clamp 18.

The clamp is tightened by means of screw 19, and is fastened to the top plate 20 by means of screws 21 and 22. The housing-cover 23 supports the top plate '20 and is .in turn supported by the housing 24 to which it is fastened by means of screws '25.

The top plate '20 contains slotted holes 26 through which screws 27 pass and are threaded into housing cover 23, so as to permit a radial adjustment of the distributor 4 .and thereby to vary the eccentricity of impeller 5 in casing 7. I prefer to adjust the eccentricity in this manner although it is obviously practicable to hold the distributor 4 in fixed relation to the housing 24 and to move the motor 10 therein.

To iacil'itate the preferred adjustment when screws 27 are slightly loosened, the top plate 20 is provided with adjustment screws 28 bearing against the stationary screws 27. Screws 28 may be manually operated or may be provided with geared heads as indicated which will represent mechanical or automatic means for adjusting the eccentricity of the impeller when the pump is operating.

The base 29 (see Fig. 5) supports the motor 10 and forms the bottom for housing 24 which is fastened to the base by means of lugs and screws 30. Sound-mufiling holes 31 admit atmospheric air to the base, and pipe nipples such as 32 convey air from the cavity of the base to the inside of the housing 24. The bottom plate 33 is fastened by means of screws 34 to the base so as to make the latter substantially air tight, subject to the aforesaid controlled openings.

The weight of impeller 5 is carried by the stationary bottom valve-plate 35 which is securely fastened by suitable means to the axle 6. This valve-plate 35 contains the arcuate inlet channel 36 communicating with the oil return scoop 3'7, and arcuate discharge channel 38 connmmieating through hole 39 with the passage through the hollow axle 6. Valve-plate 35 also contains the annular feed channel 40 communicating through hole 41 with feed supply scoop 42. also contains the annular scavening groove 43 which is relieved to approximately atmospheric pressure through the hole 44.

The impeller 5 is of the enclosed type consisting of a hub with radially disposed vanes 45 between two circular side discs (see Figs. 1, 2 and '7). The impeller contains the radially disposed liquid suction cylinder or chamber 46 provided with the suction plunger 14, and liquid discharge cylinder or chamber 4'7 provided with discharge plunger 48. Plunger 14 contains a longitudinal passage 49 communicating as indicated between cylinder 46 and the whirling ring of oil in the casing; and plunger 14 likewise contains a hole at its outer end to receive the end 13 of spring coupling 11. The discharge plunger 48 is bored out longitudinally to receive the push-rod 82.

The upper disc of the impeller 5 contains a plurality of air ports 50 disposed in a circle about its axis of rotation and communicating individually with the several pockets formed between the vanes 45. Disposed on a smaller concentric ircle are two oil feed holes 51 extending diagonally through the hub of the impeller and communicating with the feed channel 40. Still closer to the axis and disposed on a circle concentric thereto, is the oil suction hole 52 communicating with the suction cylinder 46; and at a point outside of the lower valve face of distributor 4 is located the air equalizing hole 53 (see Figs. 2 and '7) which communicates through the metal of one of the vanes 45 from the top to the bottom side of the impeller.

The lower disc of impeller 5 contains the oil port 54 communicating with discharge cylinder 4'7.

55 is an oil supply pipe which is ordinarily connected to an oil storage tank, not shown in the drawings, and which n this specification will represent the source of oil supply.

56 is an oil return pipe, likewise connected with the storage tank, for returning surplus oil thereto.

The distributor 4 has formed therein the oil suction passage 57 communicating at one end with oil supply pipe 55 and at the other end with the arcuate suction port 58. A similar arcuate port 59 serving as an air-vent, is formed in the lower face of the distributor on the same radius as 58 and communicating through supply passage 60 with casing '7.

Also formed in the lower face of distributor 4 are the sealing channel 61 and the feed channel 62. Communicating with the feed channel 62 is a needle-valve 63. The annular space around the valve stem 64 is connected by means of hole 65 with the air discharge passage 66.

Formed in a larger circle, concentric to that of the feed channel 62 are the arcuate air inlet port 6'7 and the arcuate air discharge port 68. 68 communicates through passage 66 and the comiecting pipe 69 with the burner nozzle '70, while the air inlet port 67 communicates through the hole '71 with the casing '7.

A central oil passage '72 connects the bore of axle 6 to the return pipe line 56.

The oil hole '73 in the axle serves the dual purpose of providing lubrication for the impeller bearing and, by admitting air to the hollow axle 6 when the pump is not operating, prevents siphoning of the oil from the casing.

A conventional form of packing gland is provided at the upper end of the needle-valve stem 64. The stem is threaded into the distributor at '74 so as to permit adjustment therein.

'75 is a sound mufiling device, shown in the present case as a heavy felt washer resting against the cover 15 and prevented from revolving by means of a point on the end of screw 22.

The casing '7 is provided with inwardly extending flanges '76 and '77, the inside diameters of which determine approximately the revolving surface '79 of the oil in the casing. Flange '76 is cast integrally with casing '7 and flange '77 is fastened to casing '7 by means of screws '78. Flanges '76 and '77 form the sides of two separate annular chambers into which the open ends of scoops 3'7 and 42 extend. The cylindrical surface of the oil beneath flange '76 is determined by the location of return scoop 37 as indicated by line 81.

The plug prevents leakage of oil around the shaft when the pump is not running.

The operation of my pump is as follows:

When the motor 10 is energized, the casing '7 revolves on shaft 9 and the oil contained therein is thrown by centrifugal force against the sides of the casing. The inner surface of the oil in the upper part of the casing tends to assume a cylindrical shape as indicated by the circular line '79. It is best to prime the pump initially by pouring a certain amount of oil into the casing the pumping of air but also serves to lubricatev the pump and to seal the plungers where they enter the periphery of the impeller.

The spring coupling 11 transmits rotation from the casing '7 to the impeller 5 though the medium.

of the suction plunger 14. Inasmuch as suction plunger 14 is held by centrifugal force against the wall of the casing it will be apparent that the end 13 of the spring coupling will revolve The oil in the If:

about substantially the same center as the other end 12 thereof which is pivotally attached to the casing. There will be a slight recurring accel-y eration and. retardation however of the end 13 relative to the end 12 owing to the eccentricity of the impeller axis relative to the casing but.

Under certain conditions, for instance, where more gradual starting of the pump is desired, I prefer to omit the spring coupling 11 and to transmit rotation from the casing through the frictional contact of the outer end of plunger' 14 which bears by centrifugal force against the wall of easing 7. The impact of the revolving liquid against the outer end of the plunger, etc., is sufficient to start the wheel rotating slightly, whereupon the plunger is thrown outward by centrifugal force; and the driving friction becomes cumulative as the centrifugal force increases, until full speed is reached.

Inasmuch as the plunger 14 is slidably attached to the impeller, the ecentricity of the latter may be varied with respect to the center of rotation of the casing without affecting the relative rotation of the impeller and easing 7. This is one of the important features of this invention.

Assuming the distributor 4 together with the axle 6 and bottom valve-plate to be fixed in a given position whereby a certain eccentricity is maintained between the axes of impeller 5 and casing 7, it will be apparent that the vanes will dip more deeply into the revolving cylinand rotating in the direction of the arrow from left to right as indicated in the upper half of Fig. 2, the vanes 45 gradually recede from the surface of the oil, and air is-thereby sucked into the pockets through ports and the 00- operating arcuate air suction port 67 in distributor 4. The air thus drawn in is usually supplied indirectly from the atmosphere through the muflled ports 31 in the base, from whence it enters the housing through the mufiling nipple 32, and after passing through the felt muiiler '75 enters the opening 17 in the cover 15 and passes through the port 71 in the distributor as indicated by the arrows. Some of the air may be shunted through the armature of the motor 10 as indicated in Fig. 5 in order to cool the motor.

The pulsations in the air caused by the rapid uncovering of ports, ordinarily causes considerable noise in this type of pump unless equipped with successive surge chambers with mufiled communicating passages between them. For instance, some of the sound producing pulsations are confined by the felt washer 75 and absorbed in the cavity of easing 7 inside of the revolving ring of oil. This heavy section of felt, which fits snugly against the top of the revolving casing, forms a superior throttling medium, since it offers little frictional resistance either to the casing against which it bears, or to the air filtering through it. And the resilience of the particles of which it is made tends to deaden and destroy in a large measure the sound waves which would otherwise emanate from the casing.

Most of the sound waves which do escape K through the felt 75 are absorbed in the greater cavity of housing 24, where they are confined by the restricted nipple 32. formed in the base 29 absorbs any appreciable remaining vibrations so that scarcely any noise from either the pump or motor escapes through the plurality of air throttling holes 31 in the base.

Just as the oil in the pockets between theh vanes of impeller 5 has a radial component of motion relative to the pockets, so the plungers The third chamber 14 and 48 have a 'reciprocating'motion relative to their respective cylinders 46 and 47 formed in impeller 5. It will be apparent that the stroke of these plungers will vary according to the extent of the eccentricity of the impeller in the casing '7. Consequently the amount of oil pumped by the plungers will increase or decrease with similar variations in the amount of air pumped.

The course of the oil is as follows: When plunger 14 moves outward as it will do when travelling from left to right as indicated in the upper half of Fig. 2, oil will enter the cylinder 46 through passage 52 in impeller 5, which will be supplied through arcuate suction port 58 and the passage 5'? communicating with the supply pipe 55. As plunger 14 continues to move through the other half of its cycle from right to left as indicated on the lower half of Fig. 2 (below line 11) it will be forced into the cylinder 46 and the oil will then be expelled partly through arcuate supply port 59 and the communicating passage 60 into casing 7, but mostly through the hole 49 in the plunger directly into the casing.

The passage through 60 is provided primarily as an outlet for air which may be sucked in from the supply pipe line before the latter is fully primed. If it were not for this outlet connecting with the inner end of cylinder 46 the latter would often become air bound, since it would be difficult to compress the air sufliciently to expel it through the seal formed by the whirling ring of oil in casing '7.

On the other hand the discharge of oil through hole 49 in the plunger on its inward stroke is 110 facilitated by the centrifugal force acting upon it, and this same centrifugal force on the oil acts as a check to the centripetal movement of oil from the casing into the cylinder on the outward stroke of the plunger. At the same timev 11-5- the more direct course of the oil through passage 52 and cylinder 46 eliminates the shock and hammer which a complete reversal of flow therein would cause.

Instead of relying entirely upon the centrifugal force exerted by a body of liquid in the outer end of a radially disposed chamber to suck in additional liquid at the inner end of the chamber, I have, in this invention, substituted heavier metal plungers for the liquid plungers disclosed in my Patent No. 1,906,740, issued May 2, 1938, and thereby am able to increase the suction power of the pump and at the same time to reduce its diameter. In some cases however the weight of therevolving liquid and the diameter of the impeller are such as to obtain sufficient suction with liquid pistons, but there always exists a certain amount of turbulence of the liquid entering and leaving the cylinder which tends to lessen the suction power of the pump. This turbulence is avoided by means of suction plungers having a discharge passage formed through them, and this passage may even be so large that the plunger becomes a mere guiding shell for the liquid plungers contained therein,

and a conduit for flow in an outward direction.

This revolving discharge conduit, which in its preferred form is illustrated as passage 49 formed in plunger 14, could be incorporated in the wall of the impeller, or otherwise to communicate similarly in a radial direction between cylinder 46 and a point outside of the surface 79 of the whirling ring of liquid in the casing; and

it would still operate as a centrifugal check valve to permit the flow .of liquid only outward in a radial directionassuming of course that the pump is designed so that the centrifugal force is equal to or greater than the suction required to draw the liquid from the source of supply.

As the increasing volume of oil in casing 7 flows over the inner edges of flanges '77 and 76 it is caught by the surplus return scoop 37 and carried into the arcuate channel 36 in bottom valve plate 35. Return discharge plunger 48 moves similarly to suction plunger 14 since ,it is continually forced outward, not only by centrifugal force, but also by the oil pressure derived through the scoop 37 on one half of its cycle and by the discharge pressure on the other half, and it is forced inward by the eccentric movement of the wall of the casing. quently the oil in arcuate channel 36 will enter the cylinder 47 when port 54 is in register therewith, when the plunger is moving from left to right. On the remaining half of its cycle port 54 will be in register with arcuate discharge channel 38 which communicates by means of hole 39 with the bore of axle 6, passage 72, and therefrom through connecting pipe 56 back to the source ,of supply. It will thus be seen that a continuous supply of oil is circulated through the casing 7 from the source of supply.

The capacity of the return pump cylinder 4'7 is made greater than that of the supply cylinder 46 in order to prevent flooding the casing. It is therefore necessary for the former to discharge some air in addition to the oil entering the dis charge scoop 37 in order to maintain uniform operation of the pump, and this air is supplied through the hole 53 in the impeller. 7

In the meantime feed scoop 42, projecting into the revolving ring of oil contained in that part of the casing sheltered from turbulence by flanges '76 and '77, picks up arelatively small quantity of oil and delivers it under pressure through passage 41 to the annular channel which registers at all times with the diagonal feed passages 51 extending through impeller 5. The outlets from ports 51 in the top disc of ,impeller 5 are disposed in a circle concentric to, and registering at intervals during each revolution with, the arcuate feed channel 62 in the lower face of distributor 4. The rapidly recurring discharges of oil into channel 62 tend to prevent clogging of the needle-valve 63 communicating therewith, and the oil fed through the needle-valve is carried through thepassage around the valve stem 64 to the oil feed passage 65 which conducts it into the air passage 66' through which it is carried with the air to the minute space between the adjacent faces of the impeller 5 and distributor 4-particularly in the segment between the arcuate oil suction channel 58 and the air suction port 6'7." It will be noted that a projection of the sealing groove 61 extends on a smaller radius between the oil suction channel 58 and the arcuate oil feed channel 62 thereby preventing the suction pressure obtain ing in channel 58 from affecting through leakage, the amount of oil fed through 62 to the burner as aforesaid.

It has been found that any obstruction to the Ifree whirling oil in the casing, immediately sur- Consefeed channel I rounding the impeller, -c'auses turbulence and eddy currents which impair the air-pumping function of the pump. For this reason both stationary scoops 3'7 and 42 have been separated by means of flange 77 from the upper chamber of the casing; and in order to maintain an undisturbed and uniform depth of oil around the open end of thefeed scoop 42, the second flange '76 has been provided to separate feed scoop 42 from the return scoop 37. Flange 77 serves the further function of maintaining a definite cylindrical surface for the oil revolving in the upper part of the casing substantially irrespective of normal variations in the amount of oil pumped from the source of supply, so long as the amount supplied exceeds the amount sprayed. Such variations in oil supply might be due to different oil levels in the supply tank or to air leakages through a siphon breaker used in connection with the system, etc. Usually the amount of oil circulated is considerably in excess of the amount fed to the nozzle.

Another feature of this invention consists in the introduction of a push-rod 82 inserted longitudinally into the hollow end of discharge plunger 48 in order to prevent the latter from bearing directly against the Wall of casing '7. In following the travel of the outer end of the suction plunger 14 with respect to the casing, in its travel from left to right at the top of Fig. 2, it must be apparent that the initial spot on the casing against which the plunger bears will move faster than the end of the plunger, due to the eccentricity of the impeller in the casing. On the other hand in traveling from right to left the end of the110 plunger 14 will travel faster than the opposing wall of the casing. This necessitates a sliding action between the end of the plunger and the casing. The friction caused between the suction plunger 14 and the casing is insignificant 115, owing to the complete lubrication of the point of contact, the small weight of the suction plunger, and to the fact that the suction at the inner end of the plunger diminishes its pressure against the discharge strokedepending upon the elevation of the storage tank etc.

The outer end of the push-rod 82, after sliding for a few revolutions of the pump, soon reaches a position at which it may oscillate with respect to the outer end of this hollow plunger without sliding on the casing wall, while the inner end pushes against a socket formed inside of the opposite end of the plunger. This construction eliminates friction and improves the running qualities of the pump. 7

Although I prefer to employ push-rods shaped as indicated in Fig. 1, straight rods with rounded ends asin Fig. 8, or even rollers or other freely oscillating bearing means, may be interposed between the plunger and the casing.

While only one suction'plunger and one discharge plunger are shown in the drawings for the parts.

In adjusting this pump to the varying requireinents of a given furnace it is often desirable to regulate from time to time the amount of oil and air fed into the fire-box. This may be done manually by varying the eccentricity of the impeller in the casing as above described, or by Opening or closing the needle-valve 64 to adjust the oil feed. It is often desirable however to make the oil and air adjustment automatic, in which case a control motor of conventional type may be geared to screw 28 whereby the eccentricity of the impeller may be varied automatically. The amount of oil fed to the nozzle is influenced not only by the needle-valve, but also by the depth of submergence of the open end of feed scoop 42, whereby the pressure exerted at the needle-valve may be changed. Consequently by turning screw 28 in the direction to increase the eccentricity of the impeller in the casing, more oil, by increasing the submergence ofscoop 42, and more air are simultaneously fed through nozzle into the fire-box, and by reversing the operation a reduction of both oil and air is effected.

Where the expression pumping element is used herein, it will be understood to mean one of the cooperating parts of a pumping mechanism without which no pumping action would result.

Various features of this invention may be employed without using the whole combination shown. Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the U. S..is:--

1. In a rotary air-pumping device, the combination of a rotatable casing for holding a revolving ring of liquid, air-pumping means in the casing, a liquid pumping element for supplying additional liquid to the casing, a discharge pumping element revolving with the casing, and means for supplying liquid to said discharge pumping element from the ring of liquid for discharging surplus liquid from the casing.

2. In a rotary pump, a casing, said casing having means for retaining a revolving ring of liquid, a rotatable wheel eccentrically mounted in the casing, the wheel having radially disposed chambers formed therein opening at the periphery and comunicating ports formed near the axis of the wheel, plungers in the chambers, said plungers being alternately thrown outward against the casing by centrifugal force and pressed inward by the casing, so as to pump fluid through the ports.

3. In a rotary pump, a rotatable casing for holding a revolving ring of liquid, a rotatable wheel eccentrically mounted in the casing, the wheel having radially disposed chambers formed therein, radially disposed plungers having their inner ends extending into the chambers and their outer ends bearing against the casing whereby a reciprocating pumping action is obtained by the plungers in the chambers, a conduit having its open end in the revolving liquid, and valvular means communicating with the other end of the conduit and with the chambers to conveyliquid to the chambers.

4. In a rotary pump, a rotatable casing for holding a .revolving ring of liquid, a rotatable wheel eccentrically mounted in the casing, the

wheel having a chamber formed therein, a plunge er having one end extending into the chamber and the other end bearing against the casing whereby reciprocating pumping action is ob-' tained by movement of the plunger in the chamber, and means for transmitting rotation from the casing to the wheel.

5. In a rotary pump, a rotatable casing for holding a revolving ring of liquid, a rotatable wheel eccentrically mounted in the casing, the wheel having radially disposed chambers formed therein, radially disposed plungers having their inner ends extending into the chambers and being guided by the walls of the chambers and having their outer ends bearing against the inner wallof the casing whereby a reciprocating pumping action is obtained by the plungers in the chambers, and means connecting one of the plungers to the casing for transmitting rotation between the casing and the wheel.

6. In a rotary air pump, a casing for holding a revolving ring of liquid, a rotatable impeller in the casing, the impeller being eccentrically mounted with respect to the revolving liquid, the impeller having radially disposed pockets formed in the periphery thereof opening into the liquid whereby air is compressed in the pockets, the impeller also having radially disposed liquid pumping chambers formed therein, plungers in the chambers, and means for transmitting a reciprocating motion to the plungers with respect to the chambers so as to compress liquid in the chambers simultaneously with the compression of air in the pockets.

7. In a rotary pump, a rotatable casing for holding a revolving ring of liquid, a rotatable wheel eccentrically mounted in the casing, the wheel having chambers formed therein, plungers having one end extending into the chambers, means cooperating with the other ends of the plungers for transmitting a pumping action to the plungers in the chambers, the chambers being sealed around the plungers by the ring of liquid.

8. In combination, a rotatable impeller for combined air and liquid pumps consisting of a cylindrical shaped body having radially disposed pockets formed in the periphery thereof and air ports disposed ina circle around the axis of rotation communicating with the pockets, the body. having formed therein also separate chambers in the periphery thereof and liquid admission ports communicating with the chambers, said liquid admission ports being disposed in a circle substantially concentric to but separated from the air ports, liquid pumping plungers in the chambers, and means for supplying liquid to the surface of the body between the concentric circles of ports in order to minimize leakage of air from the air ports to the oil ports therein.

} 9. In a rotary pump, the combination of a casing, a wheel mounted to rotate in the casing on an axis eccentric to the wall of the casing, the wheel having radially disposed chambers formed therein extending inwardly from the periphery thereof, plungers in the chambers, and pivotal means cooperating between the plungers and the casing to transmit positive centripetal motion from the wall of the casing to the plungers substantially as set forth.

10. In a rotary pump, the combination of a casing, a wheel mounted to rotate in the easing on an axis eccentric to the wall of the casing, the wheel havingradially disposed chambars formed therein extending inwardly from the periphery thereof, plungers in the chambers, the plungers having pockets opening at their outer ends and extending into the plungers, push-rods extending into the pockets, the pushrods bearing at one end against the bottom of the pockets and at the other end against the casing whereby the plungers are prevented from touching the casing when thrown outward by centrifugal force, the push-rods being smaller in diameter than the pockets in order to permit them to oscillate in the pockets.

11. In a rotary air pumping unit having a liquid seal, the combination of a rotatable pump casing, an air-pumping impeller in the casing, a motor for driving the impeller, a stationary housing enclosing the casing and motor, and liquid pumping means actuated by the motor for maintaining a circulation of sealing liquid through the casing.

12. In a rotary air pump, a pump casing having an air inlet port formed therein, an air pumping impeller in said casing, a housing enclosing said casing and communicating with said port, an air discharge conduit passing through said casing and said housing and communicating between said impeller and the outside of said housing, a hollow base supporting said housing, said base having a baflied air inlet opening formed therein, said base having another baflled opening formed therein communicating with said housing whereby sound producing pulsations emanating through said inlet ports are absorbed in the successive housing and base cavities.

13. In a rotary air pump, a pump casing having an air inlet port formed therein, an air-pumping impeller in said casing, a housing enclosing said casing and communicating with said port, an air discharge conduit passing through said casing and said housing and communicating between said impeller and the outside of said housing, said housing having an air inlet opening formed therein, said opening being provided with air-baffling means whereby sound producing pulsations emanating through said inlet port are confined substantially to the air within said housing.

14. In a rotary air pump, a rotatable casing for holding a revolving ring of liquid, a rotatable impeller in said casing, said impeller being eccentrically mounted with respect to said casing, said impeller having pockets and communicating ports formed therein for the passage of air to and from said pockets, a stationary housing enclosing the said rotatable casing, distributing means for admitting air intermittently from said housing to said ports, said housing having an air inlet opening formed therein, and air baffling means adjacent to said opening whereby sound producing pulsations are confined substantially to the air within said housing.

15. In a rotary pump, the combination of a revolving casing, a stationary axle in the casing with its axis parallel to the axis of the casing, the axle having a longitudinal passage formed therein, a wheel rotatably mounted on the axle in the casing, the wheel having pumping means therein and communicating ports formed in a face thereof, and a valve-plate with a passage formed therein communicating with the passage in the axle and with the ports in the wheel, said valve-plate being supported on one end of the axle.

16. In a rotary pump, the combination of a rotatable casing, a wheel having a radially disposed chamber opening into the periphery thereof and a port formed in one side of the wheel communieating with the chamber, the wheel also having a second radially disposed chamber opening into the periphery thereof and a second port formed in the opposite side of the wheel communicating with the second chamber, a stationary distributor conduit having valve-ports formed in a face thereof adjacent to and communicating with the first said port in the wheel, an axle rotatably supporting the wheel, the axle being attached at one end to the distributor conduit, the axle having a passage formed therethrough communicating with the conduit, and a valve-plate adjacentto the side of the wheel opposite to the distributor conduit, the valve-plate being fastened to the free end of the axle, the valve-plate having passages formed therein communicating with the passage through the axle and with said second port so as to circulate fluid through the casing.

17. In a rotary pump, the combination of a revolving casing for holding a whirling ring of liquid, the casing having an opening formed in one side thereof, a rotatable impeller in the casing, stationary supporting means for the impeller, the supporting means extending through said opening and through said impeller, the supporting means having a discharge passage formed therein extending through the impeller, and a stationary liquid scoop carried by the supporting means and communicating with the passage, said scoop being located at the side of the impeller opposite to the opening in the casing.

18. In combination, a source of liquid supply, a revolving casing, an annular flange extending inwardly from the wall of the casing, two pumping elements driven in unison, one of which draws liquid from the source of supply and delivers to the revolving casing on one side of the flange and the other of which draws liquid from the opposite side of the flange and delivers to the source of supply, the inside diameter of the flange thereby determining the approximate surface of the liquid in the casing.

19. In combination, a source of liquid supply, a revolving casing, two positive-displacement pumping-elements driven in unison, one of which draws liquid from the source of supply and delivers to the revolving casing and the other of which draws liquid from the revolving casing and delivers to the source of supply, the last named pumping element having a greater pumping capacity than said first pump.

20. In combination, a source of liquid supply, a nozzle, a revolving casing, three pumping elements mounted within and coacting with the revolving casing and driven in unison therewith, one of which elements draws liquid from the source of supply and delivers to the casing, one of which elements in combination with communicating means draws liquid from the casing and delivers to the source of supply, and the third of which elements draws air from said revolving casing and delivers to the nozzle.

21. In a rotary pump, the combination of a casing, reciprocating pumping means cooperating with the casing and mounted to rotate in the casing on an axis eccentric to the wall of the easing, the pumping means comprising a cylinder and a plunger and a radially disposed conduit for conveying liquid on the pressure stroke from the cylinder to the peripheral part of the casing, and a stationary liquid supply conduit communiq eating during the suction stroke with the cylinder.

22. In a rotary air-pump, an impeller, a rotatable casing enclosing the impeller, the casing having an air inlet opening formed therein, an air discharge conduit extending through said opening and communicating with said impeller, and air-baiiling means surrounding said conduit and adjacent to said air inlet opening for confining sound producing pulsations to the inside of said casing.

23. In a rotary pumping device, the combination of a casing for holding a revolving ring of liquid the inner free surface of which liquid tends to assume cylindrical shape, conduit means in said casing extending substantially beneath said surface of said ring of liquid for withdrawing a uniform supply of liquid from said ring of liquid, a discharge pumping element a discharge conduit in said casing, said discharge conduit communicating with said pumping element and having an inlet orifice located at said inner free surface of said revolving liquid to convey surplus liquid from said ring of liquid to said pumping element, and means for supplying additional liquid to said casing.

24. In a rotary pumping device, the combination of a casing for holding a revolving ring of liquid the inner free surface of which liquid tends to assume cylindrical shape, a wheel having pockets formed therein, said wheel being eccentrically mounted to rotate in said casing, conduit means in said casing extending substantially beneath said surface of said ring of liquid for withdrawing a supply of liquid from said ring of liquid, a discharge conduit in said casing, said discharge conduit having an inlet orifice located beneath said wheel at said inner free surface of said revolving liquid to convey surplus liquid from said ring of liquid, and a third conduit leading from a source of liquid supply and communicating with said wheel.v

25. In a rotary pump, a rotatable power-driven member having an annular friction driving surface formed thereon, a wheel mounted to rotate on an axis eccentric to said driving surface, a fluid-pumping element having a friction driven surface cooperating between said wheel and said friction driving surface whereby rotation of said wheel is efiected simultaneously with a pumping action between said element and said wheel.

26. In combination, a power shaft, a rotatable casing for retaining a fluid therein, said casing being driven by said shaft, a wheel in said casing, said wheel being mounted to rotate on an axis eccentric to said casing, and mechanical friction means for transmitting rotation from said casing to said wheel.

27. In a rotary pump, a rotatable casing for holding a revolving ring of liquid, a rotatable wheel in the casing cooperating with the ring of liquid, a housing enclosing the casing, a means covering the housing for varying the axis of the wheel with respect to the axis of said ring of liquid.

28. In a pumping mechanism of the character described, a casing, a first conduit for supplying liquid to the casing from a source of supply, a second conduit for returning liquid from the casing to said source of supply, a third conduit communicating with the casing, a pumping element within the casing, the rotation of said casing forming a ring of liquid therein, an air inlet to the casing, said pumping element being arranged to supply liquid to said ring fromthe first conduit and to pump excess liquid from the ring to said second conduit and to pump liquid from said ring in combination with air to the third conduit and connecting means to feed excess liquid to said pumping element for delivery to the second conduit.

WILLIAM DOUGLAS CARTER.

CERTIFICATE OF GORREGTIQN,

Patent No. 1,943,234. January 9, 1934.

WILLIAM DOUGLAS CARTER.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows? Page 1, lines 3 and 4, strike out "Patent No. 1,703,218 of Feb. 26, 1929, and Serial No. 207,707 and insert instead Patent No. 1,906,740 of May 2, 1933, and Serial No. 270,707, now Patent No. 1,856,316 of May 3, 1932; and line 63, strike out the comma af- Ier dischargefl page 2-, line 20, for "scavening" read scavenging; and that the said Letters Pateni shouici'be read with these corrections therein that the same may conformjto the record of the ease in the Patent Office.

Signed and sealed this 24th day of July, A. D. 1934.

Bryan M. Battey (Seal) Acting Commissioner of Patents.

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