US1000615A

US1000615A - Air-pump.

Info

Publication number: US1000615A
Application number: US54049010A
Authority: US
Inventors: Charles W Mcgary
Original assignee: HERBERT L HILDRETH
Current assignee: HERBERT L HILDRETH
Priority date: 1910-01-28
Filing date: 1910-01-28
Publication date: 1911-08-15
Anticipated expiration: 1928-08-15

Description

C. W. MoGARY.

Am PUMP.

l APPLICATION FILED JAN. 28, 1910.

" Patented Aug. 15,1911.

3 SHEETS-SHBET 1.

' I 0; W. M'OGARY.

Patented A 171g. 15, 1911. 3 SHEETS-SHEET 2.

j 5&5 '.Zfaz/vwavf: man@ y ya i l v fwy.

C. W. MGGARY.

AIR PUMP.

APPLICATION IILED JAN. 28, 1910.

1,000,615. v 'PatenteaAugfmlgll'f s SHEETS-SHEET 3.

A,UNITED STATES Pnr1ri-sfi- OFFICE.

CHARLES W.

MUGARY, F EVRETT, MASSACHUSETTS, wASSlKarNOIR, 0F ONE-HALF p HERBERT LIHILDRETI-I, OF BOSTON, MSSACHUSETTS AIR-PUMP.

` Specification of Letters Patent.

. Patented Aug. 15,1911.

Application inea January l2e, 1910. serial no. 540,490.-

.the following is a specification, reference being had therein to the accompanying drawings. Y O

My invention relates to air pumps or blowersjof the class in which two-rotating members or rotors inclosed in a casing cooperate to draw air in through a suction opening .and expel it under an increased pressure through a discharge opening. As heretofore constructed, so faras is known to me, blowjer's of this classhave been'able to compressl the air to a manimum pressure of only ei ht orten pounds tothe square inch, after whlch an increase in the speed of the rotors does not increase .the lamount of compression to any considerable extent. As a. result of this fact, it has been necessary to usereciprocat-Y ing air pumps where 4the vpressure desired f was greater than the amount stated. The

failureof rotary blowers as heretofore constructed to produce a pressure above ei ht or ten pounds is believed to havebeen 'ue to the fact that the pockets ofthe female rotor.

operate to carry out of the chamber in whichv the compressed air is contained a certain amount of the air under pressure, and the proportion which the amount of alr carried outb'y the female rotor bears to the amount carried in by the malerotor increases as the pressure in thedischarge outlet increases,

` so that'at a certain speed as mu'ch air. is car,-

i attempts have 'been comparatively ineifectual for the pur ose '.intended, and have ried` out by the female rotor as carried in by the malefrotor. Some attem ts have been made tOeauSethecompressed air in the pockets of the female rotor to' be discharged into the pockets of theniale rotor but such great-1y lessened th strength-of the rotating parts which must be very great to venable the rotors to run at the high speedsA required.` v l My improvedrotary air pump 1S provided with-rotors ofnovel construction which practically eliminate all pockeltnig of compressed' air anditis found in practice that an air pump embodying my construction will delllver compressedair at a pressure very much in excess of any which it has heretoforebeen possible to obtain without the use of a reciprocating air pump, so far asis known tome.

The invention will be fully understood from the following description taken in connection with` the accompanying drawings, and the niel features are pointed out and clearly defined in the claims at the close of the specification. f

In the drawings-Fi ure 1 is a vertical section of va device embo ying my invention. Figs. 2 to 5 inclusive are sections on line .2-2, Fig'. 1, showing the rotors in various successivepositions.- Fig. 6 also shows a modification intended to give an uneven or jerky suction. Figs. 7 and 8 are details showing the construction of the leakage portby means of which the' machine is kept from pounding when running at high speed: Fig. 9 is avertical section through the casing of invention, the rotors .being shown in elevashown'at 1l; the female rotor at 12; and the sov male rotor at 13.l The said casing is con- '1 `struc'ted in any convenient mannerand fits the peripheries and ends of the rotors /very closely so as to prevent' the escape of air between the proximate surfaces ofthe casing and rotor.l v Inpractice I nd it convenient to grind-in the/rotors by the use of pow-` deredemery or some other suitable abrading substance. In the'form shown in the drawings, the female f rotor is. supportedmn an axle ,14 and'themale rotor on-'an axle 15,

said members being rotated atequal speeds bypmeans of gears .16 and 17, respectively, power beingv applied to .the pulley 18.

While I have shown the two rotors as .being driven with equal speeds, it will be obvious that they ymaybe driven at. different vspeeds off rotation, 1f desired for 'any reason, so long` perlpheral'speeds'.

' The air.` to be'compressed through ,pipe 19 on the suction side of the Sthey are designed to `have the same,

is drawn in 7s "y a modified form -of air pump embodying my blower'and discharged'through pi e 2O on the'discharge side. .The casing onv 0th the suction and discharge sides is made to foll flow the circumference of the rotors as far fas possible, as will be plainly seen from Figs.

- 2 to 5 inclusive. The casing is shown as cnd` air through the discharge pipe.

ing on -the discharge side in a groove 28, which assists in the escape vof the compressed The male rotor is constructed with a plurality of longitudinal projections or blades '21, 22y and 23 which are in construct-ion practicall-y gear teeth. In practice I find three to be a convenient number of these blades.

follows what may be termedl the addendum circle, so that the periphery of the rotdr iits 4closely to the interior 0f the casing.

The pockets in the.female rotor are of a depth equal to the lbngth of the blades so that the ends of the blades contact with the bottoms of the pockets and the peripheral portion of the female rotor between two adjacent pockets contacts with thefperipheral portion of the male 'rotor lying between the roots of two adjacent blades. From this it will be seen that there is no end clearance and that the addendum circle ofthe female rotor contracts with the root circle of the male rotor. The blades or teeth and thecorresponding walls of the pockets are so constructed as to remain in contact witheach other constantly either on the walls cron the bottomof the pocket from the time the blade enters the pocket until it leaves it, so that there is the least possible leakage between 'the rotors.

By .this'means the compressed air containedv l 'j in the pocket which is open to the discharge side o the blower is forced back into the discharge side of the blower by the bladef which is entering the pocket. As the two rotors are always in contact with each other and the point of contact progresses alon the- `root circle of the male rotor up the si c of,

rthe blade, along the point ofthe blade, down the other side of theA blade, and again along the root circle toward the next blade, it will be seen that the compressed air is constantly forced backward'froln the point of contact and no escape,- except to the discharge side, ispermltted. I nd in actual .zpractice that the .contact between the-male and female members `may be made'so perfect -thatno'escapepf air` into.. the suction side of the air pump iS. tobe observed. I have accomplished this by making the blade to corres ond in shape with involute gear teeth slighty -modiied at the point. and base to prolong .the time of contact untilthe end of the tooth strikes the bottom ofthe pocket.

'It will be understood, of course, that the pockets of the female rotor also carry small quantities of air to the discharge side of the air pump, but the pockets between the bladesof the' male rotor carry in by far the greater. proportion of the air.

A It will be seen that when the position shown in Fig. 2, the air between the blades 22 and' 23 is at substantially at- Vmospheric pres'sure,"and that the air in the space between

blades

23 and 21 is at atmospheric pressure, except for any leakage-- the parts are in which may have occurred from` the discharge 'side ofthe air pump. As soon as. the blade 21 passes-the extreme edge 27 of the casing, the air under pressure from the discharge side rushes into the said space and raises the pressure untjfl/ it is equal to the pressure on the discharge side. Thereafter the forward movement of the blade 23 compresses all the air in said space and on the discharge side of the air pump until the blade 23 itself passes out of contact with the edge 27 of the casing. If the blades are fitted closely enough to give a maximum efliciency, it is found 'that pounding results due to the sud den inrush of air 'under pressure .into the space between the two adjacent blades. T o

prevent this pounding, I form a small leakage portV 28, .see Figs. 7 and 8, so that the compressed air from the discharge side of the air pump begins to iow slowly into the and. compact so that the parts may be run ata very high speed without danger of in jury from centrifugal force, but the constructiondoes not prevent the parts being made hollow if desired.

In Fig. 9 I haveshown -two rotors pro- 'vided with blades and pockets which are substantially spiral gearteeth. While such construction is somewhat more expensive to produce, it is believed that itwould tend to Vincrease materially'the quiet operation of .the blower as the pressure in the discharge side. ofthe blower is raisedless suddenly than in the forms shown in the other vfigures.

In' Fig.'6 there is shown a slight modification of'fmy rotary air pump adapted especially vfor use Uin connection withgasolene carbureters in which it is desirable t0 suck air through a carbureter', thereby causing it to 'forma mixture with gasglene introduced in the formvof a jet and to compress.

saidmixture" for-use in the cylinders of' an internal combustion .engine Under these conditions it is desirable that the suction on Ithe carlmreter be irregular at slow speeds as itis found in practice that a steady current of air moving withless than a certain Velocity will not break up the` jet of gasolene and form the desired mixture. It 1s, therefore, desirable that the suction be irregular or jerky, as thereby the formation. of the mixture at slow speedsis greatly improved. To accomplish this result, I place the suction opening 35 part way down the casing of the male rotor and make lsuch suction openin in the form of a narrow port which is close at times by the end of the blade of the male rotor. W'hen the parts are in the position shown in Fig. 6, thef'urther movement of the blade 2l of the male rotor forns a partial vacuum in the space back of said blade,

l said vacuum becoming more perfect as the saidlblade approaches the port`35. /As soon vas the blade passes the port, the gasolene miXturc rushes in suddenly to filll the Vacuum.

.at slow speeds.I 'At high speeds, littleor no difference will be seen in the action over. that of theform shown in the other figures.

lVhat I claim is:

l. In a rotary :air pump, the combination 0f a female rotor and 'a male rotor, said female rotor being provided with adseries of peripheral 'pockets and said male-rpatffi' being provided`with a corresponding series of blades equal in numberwith the pockets of the female rotor, the distances between the pockets of the female rotorbeing greater thanthe width ofthe pockets and the distanc'cs between they teeth of the male rotor casing having` two intersecting cylindri-v being greater than the width of the teeth, the spaces between the pockets ofthe female rotor being solid and the spaces .between the teeth of the male rotor being hollow,l the radius of sweep of4 the teeth of the male rotor being the same as the radi'usfof sweep of the body of the female rotor, said two rotors having their axes of rotation parallel with each other and spaced apart so that the teeth of theI male ro o will :mesh with and bottom in the pockets of the female rotor during the' rotation andthe peripheries of the bodies' of thetwo rotors will have a sliding Contact with each other'and cal chambersparallel with each other and opening into each other at their intersecing portions, the interior diameter of In this form, a little clearance is made between the female/rotor and the cas-v oth the diameter of the circle swept by said rotors whereby there is a close sliding tit of the rotors wit-hin said cylindrical chambers and'v permitting rotation of the rotors,

2. In a rotary fair'pump, the combination of a-female rotor and a male rotor, said fc- Inale rotor being provided .with a series of `peripheral pockets and said male rotor being provided with La corresponding series of blades equal in number with the pockets of the female rotor, the distances between the pockets of the female rotor being greater than lthefwidth of t-he pockets and the distances betweenthe -teeth of the mal'erotor being greater than the-width lof the teeth, the spaces between the pockets of the female rotor being solid and the spaces between the teeth of the male rotor being hollow, the radius of sweep of the teeth of t-he male rotor being the same as the radiusot' sweep ofl the body of the -female rotor, said two rotors having their axes of rot/ation parallel with each other and spaced'apart so that the teeth of themale rotor-will mesh with and bottom in t-hepockets of theA female rotor during the rotation 'andy the peripheries of t-he bodies of the.V two rotors will have a sliding contact with each other and a casing having two intersecting cylindrical chambers parallel wit-li each other and opening into each other at their intersecting portions, the interior diameter of both chambers being equal to eadh other and to the diameter of the circle swept by said rotors whereby there is-a 'close sliding fit of'the rotors within said cylindrical chambers and `cliambersloeing equal to each other-'fand to v permitting rotation of the rotors, said case ing having an inlet opening and a discharge -open1ng, s aid rotors-being at all times in lcontact with each other at some point between the inlet and the discharge openings.

3. In arotary air pump, the combination of a femal'erotor and a male rotor, said female rotor being provided with a series of peripheral pockets and said male rotor being --provided with a corresponding series of blades equal in number with the pockets of the female rotor, t-he distances between the pockets of t-he female rotor being greater than the *width of the pockets and the distances between the' teeth of the male rotor being greater than the width of the teeth, y

the spaces between the pockets of the female rotor being' solid and the spaces between the teeth of the male rotor being hollow, the radius of sweep fof the teeth of the male rotor beingthe lsame as the radius ofsweep ofthe body of the female rotor, said twlo' rotorshaving theiraxes of rotation parallel with each other and spaced apart so that the teeth of the male rotorwill mesh with the pockets of the femalrotorduring the rotation andthe peripheries of the bodies of the two rotors will Contact with each iso - cylindrical cham ers parallel with each rotors.

other and a, casin having two intersecting chambers and permitting rotation of the 10 other and opening into. each other attheir In testimony whereof I aiixx rny sgnaitersecting port-ions, the interior diameter ture, in presence of'two Witnesses.

=' of both. chambers being equalto each other CHARLES W. MCGARY. and to the diameter of the circle swept by Witnesses: said rotors whereby there is' a close shdin GEORGE P. DIKE,

lit of the rotors within said cylindrica ALICE H. MORRISON.