US2121110A - Rotary pump or compressor - Google Patents

Description

June 21, 1938. QB. YATES ROTARY PUMP OR CQMPRESSORv 7 Filed May-27, 1935 2 Sheets-Sheet 1 INVENTOR 'CHARLEJ" E L/ATLJ' BY ATTORNEY Patented June 21, 1938 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to rotary pumps or compressors and more particularly to that type of pumping equipment which consists of an enclosed cylindrical chamber in which is a hollow rotative sleeve. This sleeve has two or more symmetrically positioned transverse bores each of which con-' tains a piston which may be reciprocated therein by means of an eccentrically positioned shaft which passes longitudinally through the assembled parts and is journalled in the ends of the enclosing chamber. The aforenamed parts are so located and proportioned that rotation of the shaft causes oscillation of the pistons in their respective chambers and rotation of the sleeve at a speed which is one-half that of the eccentric shaft. 'Ports provide ingress and egress for the pumped medium.

Known machines of this type have been so constructed as to take in and discharge the pumped fluid through oppositely positioned ports in the outer casing. This has limited the ratio between the piston diameter and the sleeve di ameter to such dimensions as will insure that the piston chamber is not at any time open to both the intake and discharge ports. The general dimensions have also been limited to provide that the pistons shall'each provide a continuous cutcit between the adjacent parts of the sleeve interior. The construction disclosed herein includes but one casing wall port, hence the limitation of ratios is not required. Also this construction does not require that the pistons maintain continuous interior walls, therefore there are no ratio limitations for that reason.

Machines-of this class have hitherto required packing glands of heavy and complicated construction due to the pressure which builds up in the interior of the sleeve assembly. The construction disclosed herein makes this portion a part of the suction line to the compressing members thereby maintaining low pressures therein and making power-consuming, expensive packing glands unnecessary.

at all times to their maximum efiiciency if the discharge head has been a variable, and it has been necessary to open the discharge port at an average point and sufl'er losses at either lower or higher pressures. The improved construction herein disclosed permits the operation at any 5 head with maximum efilciency. Generally speaking the object of this invention is to provide new and useful improvements in the art of this class of rotary pump that will remove dimensional limitations, make the useof 1O complicated packing glands unnecessary, make sure that the pump will be able to function whenever power is applied and insure maximum efiiciency against any head pressure.

Referring to the drawings;

Figure 1 is a longitudinal cross-section of the compressor except the shaft which is shown in elevation;

Figure 2 is an end-view cross-section through 2-2 of Figure 1; e

Figure 3 is an enlarged partial cross-section through 3-3 of Figure 1 showing the inclusion of restrictive valves in the discharge ports; and

Figure 4 shows the compressor in assembly with an oil separator-container. 5

The pump consists of an enclosed cylindrical chamber I I as shown in Figure 1, with a sleeve i2 therein which is a running fit. This sleeve may be supported entirely by the chamber or be so journalled as to have its weight carried free of the chamber without interference with its rotation therein. This sleeve has two transverse bores l3 and l 3' at right angles to each other. In each of these bores is a piston l4 and M which is a running fit in the bore. The length of the piston with relation to the thickness of the sleeve wall is such that when one end of the piston is at the outward end of its travel the other end is partially withdrawn from the inner end of the bore in the sleeve. Their dimensions and design are such 40 that a suiflciently continuous bearing in the sleeve is provided throughout the entire oscillatory travel of the piston without offering a barring wall around or by the piston at any time. Thedriving shaft l5 passes longitudinally through the sleeve and symmetrically placed eccentrics I6 6 and I6 thereo'n locate in the bores provided in the pistons. The journals for the shaft in the ends of the chamber are eccentric to the bore of the enclosing chamber to the amount of onequarter of the full stroke of the pistons; the centers of the shaft eccentrics are also the same distance from the center of the driving shaft.

' A suitable port opening Ill and Il opposite each piston is provided in the wall of the enclosing d5 chamber, so located as to be radially in line with the end of the piston.

If the discharge head is to vary restrictive valves I8 may be placed in these ports as shown in Figure 3.

When ,using this type of compressor against pressures which are such that it is necessary that the piston open the discharge port ll before the pressure in the piston bore [3 has equalled that in H, the more highly compressed fluid is restrained from entering the bore [3 by valve l8. This valve will lift when the pressure in bore 13 exceeds that in port I1. Similarly, it will close as soon as the piston H has reached its maximum outward radial travel thereby preventing any return of compressed fluid to the interior of the pump.

Where required a suitable means IQ for sealing against oil or fluid passage is provided at the end of the chamber through which the driving shaft extends for connection to a propelling unit. This seal is not required if the pump is taking air at atmospheric pressure, if the suction pressure is the same as that surrounding the pump exterior or if the driving unit is tightly sealed into a common chamber with the pump assembly.

Lubrication is arranged in a manner which provides the ample supply of 011 required for pumps of this class and in such a way that it may not accumulate detrimentally as follows. An oil container 20 is provided either as a part of the chamber structure or separate therefrom and a conduit 2| is provided from the bottom of this container to the open end-22 of the hollowed drive shaft. Obviously any increase in pressure at the entry to the drive shaft 22 or within the oil chamber 20 will cause a flow of oil from the container to the hollow shaft. This pressure may be induced either by means of an auxiliary oil pump or, more simply, by subjecting the interior of the oil container to the discharge pressure of the pump. Such a means is shown in Figure I for purposes of illustration though no claims are made in this connection except in combination with the other parts of this application. As shown the oil container 20 serves the dual purpose of reservoir and oil separator, as the excess oil coming through through a labyrinthian channel before permitting it to leave the container at 24, this to insure the complete elimination of oil from'the discharge. The oil which has been introduced into the hollow shaft underpressure is released under the bearings in the interior of the pump through suitable ducts 25 and is distributed to all points of the interior by means of capillary and centrifugal action. In certain applications it may be desirable to reduce the oil pressure on the journals and other moving parts to a portion of that prevailing in the lubricant chamber. A suitable means for accomplishing this is the subject of another application.

In Figure 4, 28 is a one-way restrictive valve to allow the easy travel of fluid into the interior of the sleeve 26 through conduit 29 but to restrain any outward tendency through the conduit.

In operation the drive shaft l5, pistons l4 and I4 and sleeve l2 co-act and inter-act to produce a smooth even motion. The pistons are oscillatedby the shaft eccentrics and in turn they rotate the sleeve. This brings the compression chambers opposite their respective discharge ports at the proper time and carries them aw y from the ports at the point of maximum outward piston travel.

The intake to the compression chambers is through the hollowed axial interior 26 of the sleeve and over the top of each end of each piston at the inward end of its travel, and by the sides of the piston through openings 21. It is obvious that there can be no pressure in the interior of the sleeve in excess of the suction pressure, consequently the need for complicated gland structures is eliminated,they are not wholly unneccessary but undesirable.

It is equally obvious that with this improved method of construction that it is unnecessary to provide a continuous closure of the axial opening at any point, it actually is now undesirable. An

I unrestricted opening will allow free passage of incoming fluid to the intake openings above the pistons.

It is equally apparent that lubricant or other liquids which might impede action cannot accumulate in the sleeve interior as such liquids are centrifugally carried to the inner periphery of the sleeve and scavenged outwardly over the piston tops twice per revolution of the rotor assembly.

What is claimed is:

1. The combination of a cylindrical casing hav-- ing end walls and a channel through one of said walls, a rotor within said casing having a cylindrical bore extending longitudinally therethrough and forming within said rotor an inlet passage in communication with said channel, said rotor having a plurality of chambers diametrically disposed therethrough, pistons in said chambers and extending across said bore, said pistons being so proportioned to said rotor that there is free opening from one end of said rotor to the other through said bore, said pistons being adapted to open communication from said bore to said chambers at the extremities of their strokes, means to reciprocate said pistons and rotate said rotor including a longitudinal shaft extending through said bore and eccentrically disposed therein, said shaft having eccentrics thereon journalled-directly in said pistons, said shaft having a lubricant passage therein, means in said channel to restrict the movement of fluid to the incoming direction, said casing having discharge ports, means cooperative with said discharge ports to restrict the movement of fluid therethrough toan outward direction, a lubricant chamber, a pressure passage from said outlet ports to said chamber, and a second lubricant passage from said lubricant chamber through one of said end walls to said first lubricant passage in said shaft, said shaft having lubricant holes from said first lubricant passage to the bearing surfaces of said shaft.

2. The combination of a cylindrical casing having exhaust ports, a rotor within said casing having a central bore extending longitudinally therethrough and forming an inlet passage therein for gaseous fluid, said rotor having a plurality of compression chambers extending diametrically therethrough and in angular relation to each other, pistons in said chambers and adapted at the inner ends of their strokes to provide openings between said chambers and said passage, and means to reciprocate said pistons in said chambers and thereby rotate said rotor while exhausting fluid from said inlet passage through said openings, said driving means including a drive shaft eccentrically disposed through said of the travel of said pistons, and means to reciprocate said pistons in said chambers and thereby rotate said rotor while drawing fluid from said bore through said openings, said driving means including a drive shaft eccentrically disposed through said bore and having thereon eccentrics rotatably fitted in bores in said pistons.

4. The combination of a cylindrical casing having end walls and an inlet channel through one of said walls, a rotor within said casing having a cylindrical bore extending longitudinally therethrough in communication with said inlet channel, said rotor having a plurality of chambers diametrically through said rotor, pistons in said chambers and normally extending across said bore, said pistons being so proportioned to said bore that there 'is free opening around said pis-. tons from one end of the rotor to the other longitudinally, said pistons being adapted to open communication from said free opening to said chambers at the bottom of their stroke, whereby a fluid to be compressed may be conducted to said chambers, and means to reciprocate said pistons including a longitudinal drive shaft eccentrically-disposed throughv said bore and carrying eccentrics rotatably fitted in bores in-said pistons, said casing having discharge means adapted to conduct compressed fluid from said chambers.

5. The combination of a cylindrical casing having end walls and a channel through oneof .said walls, a rotor within said casing having a cylindrical bore extending longitudinally therethrough and forming therein an inlet passage in communication with said channel, said rotor having a plurality of chambers diametrically through said rotor, pistons in said chambers and extending across said bore, said pistons being so proportioned to said rotor that there is free opening from one end of the 'rotor to the other longitudinally, means to reciprocate saidpistons, said means including a longitudinal drive shaft eccentrically disposed through said bore and carrying eccentrics journalled directly in said pistons, said pistons being adapted to open fluid communication between said bore and said chambers at the extremities of their strokes, said casing having discharge ports, and means cooperative with said ports to restrict the movement of fluid therethrough to an outward direction.

6. The combination of a cylindrical casing having end walls and a channel throughone of said walls, a rotor within said casing having a cylindricalbore extending longitudinally therethrough and forming therein an inlet'passage in communication with said channel, said rotor having va plurality of chambers dlametricallythrough said rotor, pistons in said chambers and extending across said bore, said pistons being so proportioned to said rotor that there is free opening from one end of the rotor to the other longitudinally, said pistons being adapted to open communication between said bore and said chambers at the extremities of their strokes, means in said channel in the casing to restrict the movement of fluid to the incoming direction,

said casing having discharge ports, means associated with said discharge ports to restrict the movement of fluid to an outward direction, a

drive shaft jpurnalled in said end walls and eccentrically disposed through said bore, and eccentrics on said drive shaft, said. eccentrics being journalled directly in said pistons.

CHARLES E YATES.

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