US2306951A - Pump - Google Patents

Description

PUMP

Filed July l, 1939 3 Sheets-Sheet 1 iii .9

w@ Q Q@ @l l j@ i a@ "1g-7L 6.6

g /V E7 @o 1 l i I I A 19 AMK@ L'" n I l@ v /L ,aP-ira@ awww@ aafmwu -QMm-@ g@ @Mouw/1145 s G m N N E J C.

Dee., 29, 1942.

Filed July 1, 1939 3 Sheets-Sheet 2 Inventor ffrnegj Dec. 29, E942.v l. c. JENNINGS PUMP Filed July l; 1939 3 Sheets-Sheet 3 [n1/@n for IRVNG c-JENNNG'S,

Patented Dec. 29, 1942 UNITED STATES PATENT OFFICE PUMP Irving C. Jennings, South Norwalk, Conn. Application July 1, 1939, Serial No. 282,494

3 Claims.

This invention relates to pumps, and more particularly to improvements in pumps of the centrifugal air or gas compressor or vacuum pump type, whereby to increase pressure capacities with reduced or limited volume capacities.

In the conventional centrifugal compressor, a rotor is revolved in the casing, and the air is introduced at the center of the rotor from which it is expelled into a volute and discharged. The air passing through the rotor acquires a pressure and Velocity, and is discharged from the rotor under higher pressure. This principle is well un derstocd in centrifugal pumps.

A centrifugal compressor of this character is essentially a large volume, low pressure machine for the reason that one of the great losses in the compressor is the skin friction of the rotor, Which is the same for a small capacity pump as for a large one. Therefore, to obtain a reasonable efflciency, large volumes have to be handled. Also due to the lightness of the gas being pumped and the limitation of the strength of material which limits the diameter and the speed of the rotor, it is essentially a low pressure machine.

Where higher pressures are required, it is customary to mount several of these rotors o-n a single shaft, each with its own casing and the air is discharged in series through the various rotors and casings. Such an assembly requires a very expensive structure since the bearings for the drive shaft have to be widely separated to permit the insertion of the several rotors, and as the deection of the shaft is as the cube of the length, the shaft has to be large in diameter, thus necessarily reducing the size of the inlet passages in the pump.

It is accordingly a primary object of the present invention to devise a pump that utilizes but a single rotor and casing, to handle higher pressures and lower volumes than is possible in conventional pump structures, with .the corollary function that permits the operation of the rotor at lower speeds for developing the same pressure. To this end, the pump of the invention is provided with a multi-stage housing, having means to return the centrifugal discharge to the rotor inlet, through a series of stages.

Another object contemplates means for building up, and maintaining a pressure in the fluid being pumped, and repeatedly returning same to the rotor at decreased velocities.

Inasmuch as rotary pumps of the character here involved are, because of their nature, subject to appreciable wear on the moving parts, another feature has been incorporatedin the present invention which allows for adjustment between the rotary pumping member and the casing to compensate for wear at the outer periphery of the pumping member; and to provide additional adjustment at the inner periphery of the pumping member to compensate for wear on the inner periphery 0f the pumping member. The mechanism and means for accomplishing these ends, ensures, by adjustment of the clearance between the periphery of the rotor and the casing, maintenance of a sufficiently tight t as to minimize leakage between stages. Also, clearance at the inlet can be taken up by axially adjusting the relative position of the port cone and the rotor.

It is essential in operating rotors at high speeds that they be made of strong material and if the current rotor construction were followed they would be constructed entirely of steel, all of which promotes expensive equipment. It is also important to make the rotor as light as possible to reduce the stress in the rotor due to centrifugal forces. Hence an object of the invention, directed to a solution of these problems includes the provision of a composite rotary pumping member, or rotor, having the parts thereof that require great strength and machining to be made of steel, and use of the steel parts as a foundation upon which to assemble and secure the other parts that may be made of lighter material such as aluminum.

With the foregoing and other objects in view the invention further consists of a novel construction, combination, and arrangement as will be hereinafter more specifically illustrated and described in the accompanying drawings and specification, but it is here pointed out that the invention is not specifically limited to these details beyond the scope of the claims hereunto appended.

In the drawings wherein like reference characters indicate like parts throughout the several views:

Fig. 1 is a front elevation of the pump looking at the inlet.

Fig. 2 is a side elevation, partly in section through the pump taken substantially on the plane of line 2-2 of Figure 1.

Fig. 3 is an elevation, partly in section, having the parts shown in section taken substantially on the plane of line 3 3 of Figure 2, and the other parts in end elevation.

is substantially on the plane of line 3 3 of Figure 2, and the other of which planes is substantially along the line of 4-4 of Figure 2.

Fig. 6 is a fragmentary developed section along an irregular plane passing through line 6-5 of Figure 5.

Referring more particularly to the drawings, A indicates the general assembly, comprising a center part II, which is an annular member to one side of which is secured the distributing head plate I2, and to the other side of which is secured the back plate I3, both plates being secured by the customary bolts I4. The casing A is supported on a pedestal or base I which is preferably formed as part of the center part II; When parts II, I2, and I3 are bolted to-gether they form the stator of the pump, including the pump chamber I3 (Fig. 2).

A drive shaft I'I, from a prime mover M, illustrated herein as an electric motor, extends through a conventional stuiiing box I8 secured to the back plate i3, into the pump chamber I6. The inner end of the drive shaft is keyed to the hub I9 preferably formed integral with a disc 2G, secured to the impeller or rotor I, which in the form of the invention shown is a rotor of a centrifugal pump. The rotor I is locked to the drive shaft by nut 22 threaded on the end of the shaft. It follows then that the rotor I is mounted for rotation on the drive shaft in the pump chamber I6.

It is a feature of the present invention to construct the pumping member, or rotor I, so as to provide a strong and machineable foundation, upon which are mounted the lighter parts requiring less strength. This feature may be accomplshed by making the disc and hub I3 of steel,V while that portion of the rotor carrying the centrifugal chambers 23 may be made of aluminum, or other light metal, in the form of an vannulus 65 having vanes 33 on one face with a shroud 6.1 cooperative with the vanes to form the chambers 23. The annulus 65 is` bolted, as at 24, in a recess 25 about the margin of the disc 23. A rotor I is thus provided, which is of a composite nature having requisite strength where required, yet with a light weight construction effective to reduce stress in the rotor occasioned by centrifugal forces.

By constructing the rotor or pumping member I in this fashion, a cavity or pocket 26 is provided at the inner periphery of the chambers 23, all of which register with this cavity at their inner ends. At their outer ends, the chambers 23v terminate in an inclined periphery, which bears, against an inclined face of a wedge-shaped, wear compensating rim 2l and this rim is disposed in a clearance space 28 between the peripheryv of the rotor and the ilat wall 29 of the part ii of casing A, at the periphery of the pump cha-rnber i6. Adjustable lock bolts 3e in the back plate I3 have their inner ends bearing against theedge of rim, 21 to move the rim in the space 28 axially of the rotor I, take up wear, and provide proper running clearance. This rim may be made of soit bronze, phenol composition products such as Bakelite or other suitable materials. For the purpose to presently appear, the Wear compensating rim 27, is provided with openings 3i, which register with the outer ends of the chambers 23 of the rotor I, on one side, and the ends of the expanding passages in the center part II of casing A, to be presently described, on the other side of the rim.

Inv thel pump illustrated four stages of treatmore stages of treatment.

ment for the medium being pumped are shown, but it is to be understood that the present invention will operate equally as well with two or To carry out this feature there is a distributing cone or port section D formed in the head plate I2, in the pump inlet. This port or cone section D includes an inwardly projecting ported member 32, preferably, but not necessarily, shaped as a cone, formed on the inside of head plate i2, and this ported cone member conforms in shape with respect to, and fits into the cavity 26 of the pumping member or rotor I, the rotor I being revolvable about the member 32.

The head plate I2 also carries a series of conduits or passages 33, 34, 35, and 36, which compartments are circumferentially spaced from one another. The walls for these conduits are preferably cast integral with the head plate I2, and correspond in number to the number of stages of treatment applied to the medium being pumped.

The conduit 33 is the initial or main inlet to the pump, and has its outer end terminating in the walls of a pipe It that merge with a flange 4I adapted for connection with the suction line to the pump. The inner ends of the conduits 33, 34, 35, and 35, terminate at the port member 32, which is partitioned to provide four separate radially directed ports 33a, 34a, 35a, and 36a, and these ports communicate with the inner ends of the centrifugal chambers 23.

It is contemplated that the medium to be pumped will enter the inlet 33, pass through the port 33a, from whence it will pass into the centrifugal chambers of the rotor, and thence be discharged centrifugally to the next stage of the pump, acquiring velocity and pressure as it passes through each stage and is expelled at the periphery of the rotor by centrifugal force.

To this end, the center portion II of the casing A is provided with a series of expanding passages correspondlng in number to the number of stages under treatment, in the present instance four, which passages are indicated at 44, 45, 46 and 4l. One end of each passage Will register with the periphery of the chambers 23 through its respective opening 3| in the rim 21.

The passage 4i will merge at its end into an outwardly flaring discharge conduit 48 extending from the portion II of the casing, this discharge terminating in a flange 49 for connection to a discharge line.

The main purpose of the passages 44, 45 and ,r 46 is to establish communicationl between the periphery of the rotor where centrifugal force discharges the medium passing through the r0- tor, and the passages 34, 35 and 36 Ywhich lead to successive stages in the pump through ports 34a, 35a and 36a, respectively, while the passage 4'1 establishes4 communication from the final stage to the ultimate discharge at 48. These conduits or passages 44, 45, 4B and 41 have the additional function oi' converting Velocity into pressure as the fluid being pumped passes through the pump, due to their peculiar shape.

Since these passages all have the same shape, it` is believedV that a description of the one Will enable those skilled in the art to understand the other. Selecting the passage 44Y (Fig. 4) for illustration, the shape thereof is in the form of a horn, Which progressively increases in diameter from the feathering end 44u to the Wide end 44D. The Widening. ofthe passage advances in the direction ofv the, rotation of the. rotor I, and the Fluid being pumped will enter the inlet 33, pass through port 33a into the chambers 23 of rotor I, where it acquires velocity and pressure. It is then discharged into passage 44, which expands in the direction of ow, whereby the fluid is gradually slowed up to change its velocity energy into pressure. The fluid is then led into the conduit 34, at 34D, and back to the center of the rotor at port 34a, which is the inlet to the next stage.

The fluid then passes through the same cycle in its second stage, acquiring additional velocity A and pressure, and is discharged from the second stage into the passage 45, slowed up therein and reintroduced at 35a into the third stage. Again, the cycle is repeated with the attendant increase in pressure and velocity until it enters the fourth stage at 36a from which it will be discharged into the expanding discharge conduit 48, when the velocity head is changed to pressure and added to the static head.

The passage 41 differs from the other passages 44, 45 and 46 only in that, instead of having communication with a port in the cone 32, this passage merges into the discharge 48. It will be seen that the axis of the discharge 48 extends in a direction substantially tangential to the major axis of the passage 41. Passage 41 communicates with the outer ends of the chambers 23 through its opening 3| in wear ring 21 corresponding in position with the passage just as in the cases of the other passages 44, 45 and 45.

Provision is made to compensate for wear between the port member 32 of the section D (see Figure 2) and the inner periphery of the rotor I. As wear occurs the rotor I may be positioned nearer to the cone 32 either by adjustment of the bearings supporting theshaft I1, or by removing gaskets under the peripheral flange of part l2, which is integral with 32, or by inserting shims in the recess 25 between the rotor sections 65 and 23. Since the pocket 25 is of inverted frusto-conical shape, and the yport cone 32 which extends into the cavity is of a corresponding shape, it is obvious that a proper take-up of any wear will be effected readily. Any change of position of the rotor I will require readjustment of the rim 21 to eliminate leakage and provide proper running clearance at the periphery of the rotor.

It might be noted that the passage 44 and the compartment 34 form one continuous duct, the passage 45 and compartment 35 form a second duct, and the passage 46 and compartment 36 form a third duct. These ducts have their corresponding ends at one end in communication with the outer ends of the chambers 23, and have their other ends in communication with the inlet side of the chambers, in advance of the respective points of communication with outer ends of the chambers. At least apart of the advanced portion of each of the ducts, for example, that portion between the narrow end 44a and wider end 44h in passage 44, progressively widens to reduce the Velocity and increase the pressure of the medium being pumped.

The volume handled by the rotor I will be roughly about one-quarter of that handled by a single rotor of the same dimensions and speed of rotation which discharges air around its entire periphery, but the air will be delivered at approximately four times the pressure. The machine therefore becomes available for higher pressures and lower volumes, or it may be cperated at lower speeds for the same pressure. Of course the invention is not restricted to four stages; there might be any number from two up.

The drawings show a centrifugal compressor. rhe same idea could be used in connection with a Sirocco fan, which would discharge at lower pressures but the same advantages of eiiicient operation at higher relative pressure and lower volume and slower speed, with reduction in noise, would be secured. Also, the same idea could be applied to a liquid pump. The multi-stage rotor shown could be staged with an additional rotor of several stages to obtain a still higher pressure. Also, the shaft of the impeller might be mounted on bearings or driven by a flexible coupling byl any prime mover.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

l. A pump comprising a casing, a head carried by the casing, a pumping member mounted for rotation about a part of the head and having an inner and outer portion, said pumping member being provided with chambers, means establishing communication between the head and the chambers at the inner portion of the pumping member, said casing being provided with fluid conducting passages, means establishing communication between the passages and the chambers at the outer portion of the pumping member, said communication means between the passages and chambers including a wedge-shaped rim in the casing co-acting with the outer portion of the pumping member, and means on the casing to adjust the rim to regulate clearance at the outer portion of the pumping member.

2. A centrifugal pump comprising a stator, said stator being provided with a chamber, a rotor mounted in the chamber, means in the chamber between the rotor and the stator to regulate the clearance occasioned by wear, said means including a wedge-shaped rim disposed about the periphery of the rotor, said rotor having a mating surface cooperative with said rim, and means on the stator to move the rim axially of the rotor.

3. A pump comprising a casing, a head carried by the casing, a pumping member mounted for rotation about a part of the head and having an inner and outer portion, said pumping member being provided with chambers, means establishing communication between the head and the chambers at the inner portion of the pumping member, said casing being provided with fluid conducting passages, means establishing communication between the passages and the chambers at the outer portion of the pumping member, said passages being shaped to diminish flow of iiuid therethrough, said communication means between the passages and chambers including an adjustable wedge-shaped rim in the casing coacting with the outer portion of the pumping member, and means to adjust the rim to regulate clearance at the outer portion of the pumping member.

IRVING C. JENNINGS.

Images