US2147194A - Rotary vacuum pump - Google Patents

Description

Feb. 14, 1939. B, R E| 5 v2,147,194

` ROTARY VACUUM PUMP Filed Dec. 2, 1935 2 Sheecs-Sheet 1 lBY \'&\

AT oRNEY v Feb. 14, 1939. B. R. ELLS 2,147,194

ROTARY VACUUM PUMP Filed Dec. 2. 1935 2 SheetsFSheat 2 TTogNEY Patentes Feb. 1,4, 1939 ROTARY VACUUM PUMPv Burdick R. Ells, Los Angeles, Calif., assignor to Harry F. Langlois and Herbert N. Langlois, coY partners doing business as Langlois Bros.

Application December 2, 1935, serialA No. 52,499`

' 1 claim. (omen- 207) My invention has reference generally to rotary pumps, and particularly, although not necessarily, to rotary vacuum pumps of the type in which oil from a reservoir is supplied to the pump cylinder for the purpose of lubricating and sealing the piston and its vanes against passage of air thereby in order that the pump may be eflir-` cient in its formation of a vacuum.

, In pumps of this character as heretofore proposed, the quantity of oil supplied to the cylinder is ixed, and Where the pump is designed, for

` example, to supply oil to the cylinder in quantity suicient to produce an adequate sealI of the piston and its vanes when the piston is rotating at a l5 mean speed, the oil is insufficient for higher piston speeds, and in excess for lower piston speeds. An insuiiicient oil supply results in leakage past the piston and vanes of air or any other gas upon which the pump is operating, while an excessive oil supply results in such an accumulatio`n in the cylinder as to compel the oil. to be compressed before it is ejected from the cylinder.

In compressing the oil added resistance is offered to rotation of the piston; the oil becomes heated causing dilution thereof; and there is effected such an intimate intermixing ofoil and air as Ato 'form a` froth which as exhausted from the pump results in a great waste of oil. Furthermore, in previous vacuum pumps the mode of oil circulation 'lacks uniformity in distribution through the cylinder and around the piston and its vanes. This results in inadequate sealing of the piston and vanes so that the vacuum producing eiciency of the pump is greatly lowered.

It is a purpose of my invention to provide, in a' rotary pump, means by which oil is supplied automatically lto the cylinder thereof in a predetermined quantity which is directly variable in accordance with the rotational speed of the piston so that irrespective of the speed at which the pump is operating, oil in quantity sufficient only to eect adequate sealing of the piston and its vanes, is supplied to the cylinder.

It is also a purpose of my invention to provide, A in-a rotary pump, means by which the oil supplied vto the cylinder is distributed uniformly to opposite side'sof the piston so as to effect and maintain at all, times, proper sealing of all parts of the piston and its vanes. A further purpose ofmy inventionis toA provide an oil lter'particularly. adaptable to vacuum. pumps, although not necessarily, which is characterized .by its ability to separate the oil from 'theairinamannertoretaintheoilagainstbeing xed head of `,the cylinder, and the removable exhausted from the pump, and yet not impede the exhaust of air therefrom.

A further purpose of my invention is a provision of a device adapted f or use in conjunction with the oil filter above referred to, to distribute 5 the oil-laden air as exhausted from the cylinder of the pump, uniformly over the surface of the lter in order that the latter may function eifectively to separate the oil from the air.

I will describe only one form of rotary vacuum 10 pumpembodying my invention, including one form 'of filter and one .form of spreader, and will then point out the novel features in the claim.

In the accompanying drawings: Fig. 1 is a view showing in vertical longitudinal 15 section one form of rotary vacuum pump embodying my invention and including one form of filter and one form of spreader. v

Fig. 2 is a sectional View taken on the line 2 2 Off` mg. 1. 0

, Fig. 3 is a fragmentary sectional view taken on 2 the -line 3--3 of Fig. 2.

Fig. 4 is a detail perspective view of the spreader shown in Figs. 1 and 2.

With specic reference to the drawings, my l 5 inlet 2I is provided for the cylinder through which air or other gas is admitted to the cylinder, and this air afterbeing compressed in the cylinder is adapted to be exhausted into the reservoir I'I throughkan outlet `22 and finally to atmosphere through an exhaust port 23. I

That part 24 ofthe casingwhich forms the plate I8 are constructed to receive bearings 25 and 26, respectively, in which a shaft 2'I is journaled. A stuiing box 28 is bolted to the casing to confine the bearing 25 in proper position, and this box is formed with the usual packing nut 29, gland 30 and packing 3|, I

As shown in Fig. 1, the-.shaft 21 is eccentric of the cylinder I6, and fixed to the shaft by a pin 32 is a piston 33. This piston is concentric of the 50 shaft but eccentric ofthe cylinder, and itis provided with a plurality of vanes 34Y which are mounted to move radially in the piston'when the latter is rotated, as will be understood.

'I'he piston I3 is constructed to provide pockets 3S and 33 in the opposite sides thereof, and each pocket extends from the axis of the piston to a point spaced from the periphery'thereof, so that the vanes extend V-intp the pockets, as shown in/ Fig.- 1. Spiral springs 3'l are contained within the pockets to yieldably urge the vanes outwardly so that their outer ends at all times contact with the annular wall of the cylinder.- e Oil fromla suitable source (not shown) is supplied to the reservoirl'l through a pipe 38 to maintain an oil levelin the reservoir corresponding to that of'the pipe. From the reservoir, the oil can gravitate .into the pocket 36 through a feed port 39 (Fig. 2) formed in the cylinder head 24 and lhaving its exit, or lower end entering the cylinder at a point "in the side thereof which is traversed by those side edges ofthe vanes 3 within the 'area defined by the pocket.

As best shown in Fig. 1, the lower end of the port 39 is to the right of the outlet ,22 in orderv that the negative. pressures produced by and at the rear of ther-evolving vanes 34 may be utilized lto accelerate the iiow of oil through the feed port,

' as will be more fully described hereinafter.

`Part of the, oil supplied to the pocket 3S from the feed port is distributed to the other pocket 35 by the provision of ducts 40 in the piston Winch vare located atpoints spaced equidistantly about the circumference-of' the pockets.J Each duct extends obliquely of the piston with its entrance end in advance of itsexit end in respect to the induce charges of airor other gas into the cylin'- direction of rotation of the piston. In th pres- A ent instance, I have shown three such ducts, al-

though any number may be used depending upon conditions and requirements. It is important, however, that the respective diameters of the feed port 39 and the ducts 40 be such that the com-v bined oil receiving capaci-ty of the ducts` be equal to substantially one-half the capacity ofthe feed port with a given head of oil in the reservoir.

In the operation of the pump, theA piston is driven through the shaft 21, in a clockwise direction as when viewed in Fig. 1, to successively der through the inlet 2 I. These charges are then compressed in the cylinderv by the piston and vanes,"and 1inally exhausted through the outlet 22. In this manner the pump functions to produce a vacuum in respect to any air or gas receptacle to which the inlet 2i is connected.'

. Prior to and during operation of the piston, oil from the reservoir gravitates through the feed port 39 to fill the pocket 36. By rotation of the A piston oil from the pocket 36 is impelled through the several ducts 40 tobe uniformly distributed:

in the pocket 35. This impelling eifect is produced by obliquely positioning the ducts in the l' piston as previously described herein.

As the piston speed is variable in accordance with` the degree of v.vacuum itis desired to produce, while the gravitation ow of oil is hired, other means Athan gravity must be provided to increase the oil supply to the cylinder in orde'r to I adequately lubricate and effectively seal the piselo ' eral vanes when rapidly revolved..a negative" -pressure of sufficient degree-.is formed to accelerate thevoil iiow through the feed port.' As the Vvane speed increases withvthe piston speed the negative pressure at the feed-'port is increased proportionately to accelerate the oil flow accordingly. Thus, the oil supply'to the pocket 34 is caused to vary with the piston speed, and in this manner the cylinder is supplied with olivariable in quantity from .a minimum at low piston speed to a maximum at high piston speed.

By proper design of the feed port and vanes, and maintaining a proper head of oil in the reser` voir, at no timeA will the quantity of oil supplied to the cylinder be excessive, but just sufficient to adequately lubricate and seal vthe piston and vanes, so as to maintain the pump at its highest degree of efficiency.

. Not only do the ducts 40 serve tol conduct and impel oil fromone pocket to the other, butthey,

function to vary the oil ow therethrough inI direct accordance with variation in speed of the piston. Where 'the relative oilcapacity of the.

feed port and ducts is as previously described herein,y the amount of oil distributed to `the pocket 35 will be substantially half of that suplplied to the pocket 36, at any and all piston a solid support.` or back made of vtwo metal plates 4I and 42 welded vto each otheri The lower V plate isperforated to receive tufts 43 of wire or any other suitable material, and the wires of each` -tuft diverge to their free ends so that the latter are spaced one from the other. \Brackets, 44, 44, 'are welded to the upper plate 4I, and by screws 45, 45, they are secured to the inner side of the pump casing. to support the filter horizontally within the oil reservoir and directly over the outlet 22. i

In practice, thenlter functions as rouws: As

the stream .of oil bearing air exhausts from lthe pump outlet it impinges against the tufts, and is thus minutely subdivided by .the wires torcause the oil to be retained between the wires and thus separated from the air. back functionsI as a baille to retard the llow of oil and airI and spread the stream laterally so Vfilter embodying myl invention. whichcomprises f- The filter support vor that that oil not separated by" the wires the stream moves upwardly, is retained Vbetween the wires as the stream'moves horizontally beneath the filter back. As the oil collects onthe wiresl it falls back into the reservoir to be recirculated through theA pump.

For the purpose of distributing the oil-bearing air uniformly over the under surface of the filterso that a more complete vfiltering of oil from air,`

'is effected, I provide a fluid spreader which comprises a tubular bodyl 46 supported horizontally beneath the lter by a short length of pipe 41 which "extends into'the outlet 22 andjis secured therein `by a screw .48. The body 46 is provided in its top witha longitudinal slot 49 which, as

lshown in Fig. 4, decreases in width fromv its ends to its ce'nter or medialportion.

It is' at this medial portion of the filter body that the uid stream from the-pumpenters the body through the pipe '41, and as the slot is -re stricted at this .point the body serves to spread the streamv in opposite directions along the length of the body to be emitted `uniformly along 9,147,104 3. ,indem d port lending from the bottom oftheV reservoir downwardly toaaid cylinder at one siciek of the piston so as to deliver oil to one of said pockets; vanes movable radially in the piston so .lonlyonefrmotrotarylnnnnoneformofoil as to have sweeping contact with the lower end 5 5 lter,'and oneform ofspreadenea'ch my invention, it :im he mom-iam changesandmayhemadeherein .without departing from the spirit of my invenof said port to produce suction in the port and to thereby accelerate the ow of oil to said` pocket'i'rom the reservoir in direct proportion tionand the spirit 'andsoope of the appended to the revolving movement of the vanes; and auxiliary pumping means comprising ducts ex- 10 tending `ohlieluely in the direction of rotation 5m through the piston f rom one pocket to the other adjacent the outer edges thereof for impeliing oil from that pocket to which oil issupplied to the other pocket. A y g .v v BURDICK R;

I claim: f,

q A rotary pump having a vertically disposed cylinder, a horizontal shaft rotatable in the cylinder; a vertically disposed prkton in the cyl-v 15 inderamixedtosajdhaft; pocketsonefin each side of thepiston; oilrelervoir above the cyl-

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