US2392543A - Pump - Google Patents

Description

J. MERCIER Jan. 8, 1946.

PUMP I Filed May 15, 1940 Li "Iii? fnbeflior: JEAN MERE/ER remedies. s, 1946 UNITED STATES PATIENT, orFlcE' Jean Mercier, Neuilly-sur-Seine, Francepvested in the Alien Property Custodian ApplicationMay 15, 1940, Serial No. 335,386 I In France June 22, 1939 I 7 Claims. ,(01. 103-5) The present invention relates to pumps for liquids, more especially for use on aircrafts.

A pump of the considered type is shown in my French Patent 809,826." Pumps of this type when used on aircraft do not work satisfactorily when the oil to be pumped becomes cold and consequently less fluid. The suction exerted by the device.

plungers may then become insufilcient and this I disturbance is particularly inconvenient if the low temperatures are accompanied by a drop of 3 the atmospheric pressure. This drawback can a angles to the axis of revolution and no liquid'is be obviated according to theinvention by utilizing the centrifugal force exerted by the rotating parts of the pump.

According to the invention the liquid to be supplied to the'pump is introduced into the central part. The aforesaidforcethere produces a suction effect which facilitates the arrival of liquid.

Under the action of the same force the liquid is carried to the periphery. The pressure exerted on the liquid, thus, rises fromthe center towards the wall of the casing. The liquid to be fed to the cylinders is isolated at the point of highest pressure and from there conducted into the individual feed channel of each-cylinder.

For that purpose I have found it advantageous to provide an annular wall ,disposed at a short distance from the wallet the casing, and reaching up to a point immediately adjacent the turning parts of the pump. I thus create a peripheral groove into which the oil is forced and from which it is withdrawn near the bottom into th feed channels of the individual cylinders.

However, the same purpose can be obtained by leading the feed channels of the cylinders up to a point adjacent the turning parts of the pump.

to the factthat the space located beyond the tion,- said' push-piece bearing against the cam and being subjected to the thrust of an elastic Therefore, this pump ensures regulation of the discharge pressure,- since the inclination of the' cam depends upon the value of said pressure. For a given maximum value of this discharge pressure, the camis at right any longer discharged by the pump,

In the pumps of the known type, the inlet and outlet conduits or channels werefprovided at one end of the pump and they were directly connected with.the ends of the cylinders containing the pistons. Now, this arrangement, although it gave very satisfactory results under ordinary working. conditions, has been found to be insufficient in the case of very high Working speeds ofthe pump,

and especially when re-starting a pump which has been stopped for a certain time. This is du'e pistons ends and which contains the cam is, in

hand, to the conduits 01; channels through which This structure insures regular supply of liquid to the cylinders'and facilitates restarting of the pump after a period of idleness. r i

A pump of this kind includes a plurality of parallel pistons, preferably disposed along'generatric'es of a circular cylinder, and. actuated by means of a rotating cam. This cam is mounted to oscillate with respect to a piece, intended to give itits rotary movement, about an axis perpendicular'to the axis. of rotation of'said cam with respect to. saidpieee. The oscillations of the cam about said axis of rotation are produced, "in the direction which tends to reduce the inclinationof the cam, by the reaction of the pistons resulting from the action of the liquid that is discharged and of the return springsand, in

the opposed direction, which tends to increase the inclination of the cm, by the action of'a sliding pushpiece parallel to the axis. of revolu- 5 this latter case, nearly empty and must be connected, on the one hand, toa special conduit serving to ensure the restarting, and, on the other the inflow of fluid to the cylinders takes place. i

The general object of" the present invention is to provide a pump. of the type above mentioned which is better adapted to meetthe requirements vide a pump of this type working in a perfectly smooth and regular manner.

According to'an essential feature of the present invention, the supply conduit or conduits of the pump open directly into the space containing thecam and located beyond the piston heads, and the particular and individual inlet conduits or channels provided for each cylinder respectively open into the peripheral zoneof the abpve mentioned space surrounding the cam.

a It, will be readily understood that in the case of a very quick rotation of the parts contained in the space surrounding the cam, there is pro*.

duced,,under the effect of the centrifugal force I resulting" from this rotation, extra-pressure in'the above mentioned peripheral zone. If the an automatic cylinders are fed with fluid coming from this zone, two advantages are obtained:

(a) First, the feed remains always perfectly regular, and 1 (b)- Re-starting becomes an easy operation, automatically obtained without any special device, owing to the above mentioned pressure,

.vicinity. of conduits I8, which ensures a correct which is established as soon" as the parts of the pump are started rotating.

Other features of the present invention will result from the following detailed description of specific embodiments thereof.

A preferred embodiment of the present, invention will be hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which: a

Figure 1 is an axial sectional view of a pump of the type above mentioned made according to the invention. Fig. 2 is a cross-sectional view taken on line 22 of Fig. 1 and Fig. 3 is a detail sectional view taken on line 3-3 of Fig. 2.

In the embodimentof the invention shown by the drawing, the pump includes a plurality of cylinders I, in which are slidably mounted pistons 2 subjected to the action of return springs 3 bearing on the one hand against the block 4 in which the cylinders are provided, and, on the other hand, against pieces S'belonging to the pistons. These pistons 5 carry the balls 6, flattened on one side, which bear on a cam I. This cam restarting, which is a very interesting result obtained without any special device.

In'view of ensuring a sufficient pressure at the inlet check valves, it is preferable to incline the inlet conduits, taking of course into account the direction of revolution of the pump. Also, I may make these conduits with the shape of blades, especially at the inlet end thereof.

The end portion Iaof the cam may be made of the shape of the blades of a turbine, which further'drives the liquid toward the periphery. The cam I is rotated by the tube I3 which is supported on bearings I4 and I5. Thus the blade portion IA and the end portion of the tube I 3 on which the cam is mounted will rotate with a turbine'eflect to drive. the liquid to the inner tensive circulation of the liquid in the casing.

includes two plates 8 and 9, which are capable of rolling with respect to each other, owing to the provision of ball bearings I0. Plate 9 is pivoted at I I to a lateral piece I2, carried by a tube l3 which is caused to rotate about the axis of the apparatus by meansof any-suitable motor, not shown. This tube is mounted on bearings I4 and IS. The plate 9 is normally forced outward from its pivotal support II by a piston lb 1 slidably mounted on a shaft Id and pressed outwardly by a spring and clutch arrangement 1c.

. parts of the pump and connected through channels I9 with the ends of the respective cylinders I. Channel 20, provided with check valves 2| connects the ends of the respective cylinders l with the discharge 22.

The operation of the pump above described is as follows:-

As a rule it is identical to that of the pump described in the above mentionel French patent. Tube I3, brought in rotation and driven by any suitable motor, rotates cam 89, the inclination the fluid fed by the pump.

The fluid is in space I6 surrounded by the casing 28, to which it is fed through tube II. It is driven in rotation and 'under the effect of the centrifugal force it is expelled into the peripheral zone of space I6 which is in communication with channels or grooves I8. An extra-pressure is produced in the zone in question and it is clear that, under these conditions, cylinders I are. fed with fluid under a given pressure. Furthermore, when the pump is being restarted after having been stopped for 'a more or less considerable period of time, the rotation of the elements present in space I6 produces an overpressure in the Blades 24 may also be provided onithe outer surface of the pump body and they further improve the c 00ling..

A.n orifice 25, of small cross section, may be provided in the push piece acting on cam 1, so as to deaden the oscillations produced by the reciprocating movemnt of this push piece. The rotation of the cam and revolving head is utilized for turbine action. One or more blades may be added on the periphery of the cam to enhance turbine action. The turbine action creates a suction effect at the center of the cam which draws fluid into the pump. This fluid is carried' mix or circulate within the casing and thus lose its pressure, This would defeat the purpose of the inventionwhich is to facilitate the intake of the fluid through tube IT by suction andfeeding of fluid to the cylinders under pressure.

Screen D isolates feeding fluid, adjacent to the point of highest pressure (Hi), from the rest of the fluid in pump, so that the centrifugal pressure'developed forcesfluid through channels I8 into cylinders I.

To avoid loss of charge when fluid is forced down through an annular groove 26, curved blades as shown in Figs. 2 and 3, may be provided to guide the fluid.

The suction force in the center of the swash "plate-(9) and the expulsion of part of thefluid of which is variable according tothe pressure of r through port or ports 23 is of great advantage since it insures a constant flow of fluid through the pump even after the swash plate is concentric; so that no pumping is effected. This circulation of liquid cools the pump which might otherwise become overheated, or'retain suflicient heat in the fluid inthe reservoir in case of'aircraft where frequently the pump must operate under extreme cold.

The introduction of fluid under pressure into' and form of the parts without departing from the principle of the present invention 'as comprehended within the scope of the appended claims.

What I claim is:

1. A pump which comprises a pump casing, a plurality of cylinders arranged in circular series around the longitudinal axis of said casing. in one portion thereof, a piston associated with-each cylinder and extending into said casing, a revolving head journalled in the other portion of said casing, a cam carried by said revolving head and contacting the'heads of said pistons, sa'ld' cam .being, at least in its normal position, inclined with respect to said axis, means for supplying fluid to the central portion of said casing at a point distant from the periphery thereof, a circular wall close to the periphery of said casing extending axially from a point adjacent said cam to the opposite end of said cylinders and forming a peripheral groove along the periphery of said casing, a conduit extending from each said cylinder to saidgroove and means to discharge fluid from said cylinders through at least one second discharge port in said casing.

2. A pump which comprises a pump casing, a plurality of cylinders arranged in circular series around the longitudinal axis of said casing in one,

portion of said casing, a piston associated with each cylinder and extending into said casing, a

revolving head journalled in the other portion ofsaid casing, a cam carried by said revolving head and contacting the heads of said pistons, said cam being, at least in its normal position, in-

cent said cam to the opposite end of said cylinders and forming a peripheral groove along the periphery of said casing, a conduit extending from each said cylinder to said groove and means to discharge fluid'from said cylinders through at least one second discharge port in said casing,

3. A pump which comprises a'pump casing, a plurality of cylinders arranged in circular series around the longitudinal axis of said casing in one portion of said casing, a piston associated with each cylinder and extending into said casing, a revolving head Joumalled in the other portion of said casing, a cam carried by said revolving head and contacting the heads of said pistons, said cam being, at least in its normal position, inclined with respect to said axis, means for supplying fluid to the central portion of said casing at a point distant from the periphery r thereof, a conduit extending betweeneach of said cylinders and a point adjacent the periphery of said cam and means to discharge fluid from'said cylinders. l

4. A pump according to claim 3, m which said conduits are inclined in a direction opposed to the. rotary flow of fluid engendered by the rotafeeding fluid from said source to said chambers at a pressure greater than that at which the fluid istaken from said source, and a cam means in said chambers for increasing the pressure of said fluid while said cam remains in an eccentric position during rotation and for automatically stopping the increase oi said fluid pressure when a predetermined maximum pressure forces said cam to be positioned in a-concentrie position during rotation.

6. In a device of the character described. the

combination with a source of fluid of a series of fluid receiving chambers disposed in parallelism at equal distances mm a common axis, booster means rotatable about said common axis for feeding fluid from said source to said chambers at a pressure greater than that at which the fluid is taken from said source, and means in said chambers for increasing the pressure of said fluid and means for automatically stoppi theincrease of said fluid pressure when a predetermined maximum pressure is attained.

7. A. pump which comprises a pump casing, a

I plurality of cylinders arranged in circular series around the longitudinal axis of said casing in one portion thereof, a piston associated with each cylinder and extending into said casing, a revolving head journalled in another portion of said casing, a cam'carried by said revolving head and .contacting the heads of said pistons, said cam being, at least in its normal position, inclined cured to the periphery of said cam to increase its turbine action.

JEAN

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