US2068570A - Rotary pump - Google Patents

Description

A. A. ROSS ROTARY PUMP Jan. 19, 1937.

Filed Sept. 14, 1933 Inventor: Aubveg ARoss, by 34%, z? WW4,

His Attorney.

Patented Jan. 19, 1937 UNITED STATES ROTARY PUMP Aubrey A. Ross, Marblehead, Mass., assignor to General Electric Company, a. corporation of New York Application September 14, 1933, Serial No. 689,409

Claims.

The present invention relates to rotary pumps for conveying or compressing a fluid, more particularly to the kind of pumps having a pump chamber and a rotor projecting into and being 5 eccentrically arranged with the pump chamber and defining slots for guiding a plurality of pistons which are in engagement with the wall of the chamber.

The opject of my invention is to provide an improved construction and arrangement of the kinds of pump above specified which is simple in manufacture and eflicient in operation.

A more specific object of my invention is to provide a construction having a rotor fastened to the shaft of a gearing or a turbine or like prime mover having axial play wherein no leakage occurs due to the axial play of the prime mover shaft.

For a consideration of whatI believe to be novel and my invention, attention is directed to the following description and the claims appended thereto, in connection with the accompanying drawing.

In the drawing, Fig. 1 is a perspective view,

partly broken away, of a pump embodying my invention; Fig. 2 is a sectional side view of the pump shown in Fig. 1; Fig. 3 shows the elements of the pump disassembled; Fig. 4 shows a sectional front view of a modification embodying my invention; Fig. 5 is a front view with certain parts removed of a further modification; and Fig.

6 shows a part of Fig. 5 to an enlarged scale.

My improved pump comprises the following elements, best shown in Fig. 3: an inner end plate In having a central bore provided with annular grooves I2, a rotor or carrier or runner I3 having a threaded shaft l4 and a plurality of slots l5 defining segmental projections l6, l1, |8, |9, a sealing plate 20 having openings 2| of a cross section corresponding to that of the segmental projections I6 to I9, an annular pump casing 22 having two lateral openings 23 and 24 provided at substantially diametrically opposite points and two recesses 25 and 26 at its inner surface defining ports communicating with the openings 23 and 24 respectively, a guide member or roller 21 and a plurality of pistons or piston members or rollers' 28, 29, 30 and 3|, another sealing plate 32 having the same shape as the sealing plate 28 and an end plate 33.

Referring now to Fig. 1, I have shown the elements of the pump assembled with the rotor driven by a prime mover having a shaft 34 and a casing 35. The prime mover may be a gearing, a turbine or the like. The inner end plate ll) of the pump is fastened to the casing 35 by means of bolts 36. The rotor I3 is screwed with its threaded shaft |4 into an axial bore of the shaft 34. An intermediate annular portion 31 of the rotor is packed against the inner grooved surface l2 of the end plate l0. In the grooves I2 I may provide any suitable packing or I may provide a sliding fit between the rotor member 3'! and the plate I0. In the latter case it is preferable to make the plate ID of bronze, the rotor 31 being made from steel. The pump casing 22 together with the outer end plate 33 are fastened to the inner end plate II] by means of bolts 38. The projections l6, l7, I8 and IQ of the rotor project into the pump chamber defined by the pump casing 22 and are eccentrically arranged therewith, the arrangement being such that in a certain position of the rotor one of the segmental projections, in the present instance projection I8 (Fig. 2), defines a slight clearance or a sliding fit with the inner surface of the pump chamber at a point intermediate the ports 25 and 26, whereas another segmental projection I6 defines a large clearance with the inner surface of the pump chamber at a point. diametrically opposite the small clearance defined by segment I 8. It will be readily understood that these relations vary in accordance with the number of segmental projections and the arrangement of the ports 25 and 26. Provided in the center of the pump chamber is the guide member or roller 21 and located in the slot defined by the segmental projection are the pistons 28, 29, 30 and 3|, in the pres znt instance shown as rollers having the same diameter as the roller 21 and being in constant engagement with the latter as well as with the inner wall of the pump chamber. The inner and outer ends of the segmental projections project through the openings 2| of the sealing plates 20 and 32 respectively, the arrangement being such that the segmental projections have a sliding fit in the openings of the sealing plates. The rollers or pistons 28 to 3| are located intermediate the sealing plates with their end faces slidably engaging the corresponding faces of the sealing plates. The latter are located in eccentric annular recesses 39 and 39a. in the faces of the pump casing, the sealing plates being restrained from axial movement, whereas the rotor with the projections may move axially.

-Fastened in the openings 23 and 24 of the pump casing 22 are conduits 40 and 4| respectively. The elements are arranged to permit operation of the pump in both directions. Assuming clockwise rotation of the prime mover shaft 34 and the rotor l3, the operation of the pump is as follows:

The two pistons 30 and 29 together with the segmental projection I9 and the cylindrical contour of the pump chamber form a somewhat crescent-shaped space 42 in commiuiication with the port 26 and the inlet conduit 4|. As the rotor together with the pistons rotate in clockwise direction, the space 42 increases, creating a vacuum and causing fluid to enter through the conduit 4! and the port 26. Said space increases until it reaches a maximum. In the position shown in Fig. 2 such maximum space is defined between the pistons 28, 29 together with the projection l6 and the wall of the pump chamber. In this condition said maximum space does not communicate with the inlet port. As the rotor and the pistons, which together form in substance displacement means, rotate further, communication is established between said maximum space and the port 25, whence the-space decreases, thereby causing fluid to be compressed and expelled through the port 25 and the outlet conduit 40. This is a known operation of pumps of the kind specified.

An important feature of the arrangement just described is that all pistons are in constant engagement with the central roller or guide member 21 as well as the wall of the pump chamber. The pump therefore does not depend upon centrifugal forces exerted on the pistons and acts at low as well as at high speeds.

Another important feature is the provision of the sealing plates. These plates .permit axial play of the rotor without thereby causing leakage of v the pump. It will be readily understood from a consideration of Fig. 1 that without the plates leakage would occur during axial movement of the rotor because such movement would establish a direct communication between the inlet and the outlet of the pump. No such communication is possible with my arrangement as long as the axial play of the rotor is less than the thickness of the sealing plates. This is a distinct advantage in that it permits the rotor of the pump being directly screwed into the shaft or if desired form a part of the shaft of a prime mover having axial play without necessitating the provision of special coupling means between the pump and the prime mover shaft.

The guide member or roller 21 of the arrangement just described remains in concentric relation with the pump chamber during operation of the pump. This permits fixation of the guide member with the outer end plate 33. Such an arrangement has been shown in the modification of Fig. 4 which comprises a drive shaft 45, a pump rotor 46 fastened to the drive shaft 45, an inner end plate 41 corresponding to the plate ID of Fig. 1, a pump casing 48 corresponding to the casing 22 of Fig. 1 and an outer end plate 49 corresponding to the end plate 33 but difiering therefrom in that it has attached to it a. central guide member 50 corresponding to the roller 21 of Fig. 1. The rotor 46 has projections extending through sealing plates 5| and 52. The sealing plate 5| is similar to the plates 20 and 32 in Fig. 1, whereas sealing plate 52 differs from said plates by the provision of a central hole 53 having a diameter larger than the diameter of the central guide member or shaft 50. This is necessary because the plate 52 rotates together with the rotor eccentrically about the guide member 50. Adjacent projections have parallel sides defining a slot for accommodating piston members. The operation of the pump is similar to that described above in connection with Figs. 1 and 2.

In Fig. 5 I have shown a modified arrangement of a pump structure with the end plate and the end sealing plate corresponding to members 33 and 32 respectively of Fig. 1 removed. The structure comprises a casing 60 defining an annular chamber 6|. Eccentrically disposed within the annular chamber 6| is a rotor 62 having a central bore 63 and a plurality of slots 64. A guide member or roller 65 is located within the bore of the rotor in concentric arrangement with the pump chamber. A piston shown as a plate or vane 66 is located in each slot. Each vane has cylindrically formed end surfaces engaging the guide member or roller 65 and the wall of the pump chamber. The inner surface-of the pump chamber is recessed at opposite portions to form ports 61. The ports are connected to channels 68 and 69, acting as inlets and outlets of the pump.

The cylindrical end surfaces of the vanes or plates reduce to a minimum frictional losses during the operation of the pump. In case the thickness d (Fig. 6) of the plates is comparatively great in relation to the length D of the plate, such a plate may be manufactured in a simple manner by cutting segmental portions 10 from a cylindrical body as indicated by dotted lines in Fig. 6. The use of plates 66 instead of rollers 28 to 3| (Figs. 1 and 2) permits the provision of a great number of vanes or plates in a comparatively small pump space. The operation of the pump shown in Fig. 5 is similar to that described above in connection with Figs. 1 and 2.

Having described my invention together with the apparatus which I now consider to represent the best embodiments thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a rotary pump, a casing defining an annular pump chamber having inlet and outlet ports, a rotor with a drive shaft eccentrically arranged with and projecting into the chamber and having radial slots and axial projections, a guide member centrally disposed in the chamber, a plurality of pistons, each piston being slidably arranged in one of the slots of the rotor and en-. gaging the guide member and the inner wall of the chamber, and sealing means for preventing flow of fluid from the outlet towards the inlet during axial play of the rotor, the sealing means including a plate having openings receiving the axial projections.

2. In a rotary pump, a casing defining an annular pump chamber having inlet and outlet ports, a rotor eccentrically arranged with and projecting into the chamber and having axial projections and radial slots, 2. guide member centrally disposed in the chamber, and a plurality of piston members slidably arranged in said radial slots in the rotor and in constant engagement with the guide member and the wall of the chamber, and sealing means comprising a rotatable plate facing the end faces of the piston members and having recesses receiving the axial projections formed between adjacentislots of the rotor to prevent leakage between the inlet and the outlet during axial play of the rotor.

3. In a rotary pump, a casing forming an annular chamber with ports, a rotor having a plu- 75 rality of radial slots to define projections and being eccentrically arranged in the chamber to slidably engage the chamber wall at a point intermediate the ports, a guide roller provided in the center of the chamber, a roller in each slot engaging the guide roller and the inner wall of the chamber, and two plates having openings for receiving both ends of each projection to prevent leakage during axial movement of the rotor.

4. In a rotary pump, a casing forming an annular chamber with ports, a rotor having a plurality of radial slots to define segmental projections and being eccentrically arranged in the chamber, an end plate with a guide member fixed thereto and projecting centrally into the chamber, a plurality of pistons in the slots, each piston engaging the guide member and the chamber wall, and a sealing plate arranged in a recess of the casing and having openings receiving the ends of the projections to permit axial play of the rotor without affecting the pumping action.

5. In combination, a prime mover shaft subject to axial play during operation, a pump having a casing with an inlet and an outlet diametrically opposite the inlet, a rotor eccentrically arranged in a, chamber defined by the casing, the rotor having axial play in the casing, and having a portion rigidly secured to the shaft, and sealing means for the pump to prevent leakage between said inlet and outlet during axial play of the prime mover shaft, the sealing means including a plate rotatably disposed in an eccentric recess of the casing and having openings receiving end portions of the rotor and forming a sliding fit therewith to permit relative axial movement between the end portions and the sealing plate.

AUBREY A. ROSS.

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