US2642003A - Blower intake port - Google Patents

Description

June 16, 1953 J. E. WHITFIELD 2,642,003

BLOWER INTAKE PORT Filed Dec. 16, 1949 4 SheetsSheet l 5 4 3 INVENTOR.

JOSEPH E.WHITF|ELD Attorney June 16,1953

Filed Dec. 16, 1949 J. E. WHlTFl ELD BLOWER INTAKE PORT 4 Sheets-Sheet 2 'FiG.4

lwmroa JOSEPH E .WHITFIELD June 1953 J. E. WHITFIELD BLOWER INTAKE PORT 4 Sheets-Sheet 3 Filed Dec. 16, 1949 INVEN TOR. JOSEPH E. WHITFIELD BY A f forncy J. E. WHITFIELD 2,642,003

June 16, 1953 BLOWER INTAKE PORT Filed Dec. 16, 1949 '4 Sheets-Sheet 4 INVENTOR. EIYQSEPH E .WHITFIELD Aflorney Patented June 16, 1953 UNITED STATES PATENT OFFICE 2,642,093 BLOWER INTAKE Pom Joseph E. Whitfield, Erie, Pa assigner vto Bead Standard ,Goigporation, a ce'rporatien of Dela n -D cember 16, 1949, Se ia N 1 1 .95

J2 .Glaims.

This invention relates generally to fluid pumps, motors, blowers, compressors andsi ar devices of the type employing rotary engagingme'mbers provided with helical intermeshing'threads, and more particularly to the housing whichenclos'es .and cooperates with the rotary members to pro- ,duce a fluid device havingdefmite operating characteristics.

Fluid devices of the type described have a pair of rotatably mounted rotors provided with complementary 'intermeshing helical threads" and grooves preferably of such configuration to provide a continuous seal line therebetween and which cooperate with the walls of the chambers in which they rotate to form fluid pocketslthat .advance from one .end of the chambers to the other. When operating as a motorthe fluid pressure on the faces of the rotary ,membersj propels them, and when operating aSa Dump, blower or compressor the fluid is propelled by therotation :of the intermeshin rotors.

The male rotor, referred to asthe main rotor, has preferably all .or full addendum threads with the pitch :circle being substantially at the root diameter. The female rotor, referred to as the gate rotor, has its complementary threads ,all or full dedendum with the pitch circle being v substantially at its outside diameter. Thesecompleof the helical main rotorthreadsj-are generated mentary intermeshing helical threads form acontinuous seal witheach-other since thec'urved sides or described by the continuouscrest edgesof the helical threads of thegate rotor, and the euryed troughs .of the gate rotor a e generated or described by the continuous crest edgesof the helical threads'of themain rotor. -These rotarymembers are shown and described in :my United, States Patent 'No.12,28'7,'716, granted June 23, 19,42.

The -intermeshing rotary members .operate ,in parallel cylindrical chambers which mergeinto one another, 'formingr-a larger chamber, somewhat in the formcf -a flgure 8.:in cross section. Theoretically, the rotary members -forma continuous-seal with each other :and theirperipheral surfaces seal with the walls of their respective chambers. Actually it is desirablethat they have a running clearance to prevent actual contact, and this clearance depends'on the-sizeof the apparatus. However,the-clearance is so small that an effective seal is provided. This spaced-relation of the rotors is maintained by timinggears although they are capableof driving one another.

The ports are'located at diagonal corners ;of the housing or casing and extend over-a portion of the ends and sides of ,thetwo chambers-to provide both axial and radial communication with the rotary members. If the ports are the same size and shape at each end, the direction of rotation of the rotary members determines which is the inlet and which is the outlet. In the present invention, oneof the ports and its passage is particularly designed to serve as the intake, and the rotary members are therefore rotated in a direction so'that the pockets formed by the rotors together with their chamber walls advancefrom this intake end of the chambers to the'other or tle end 9f th c am er The present invention has as its primary object, the provision of a device of the type described having improved performance through an improved fluid intake port and port passage construction particularlyadapted to facilitate flow of fluid into the pockets formed by rotation of theprotors.

In devicesof ,he ty e described, wherein the fiuidintake provides for radial admission of fluid to the rotors, it has been found that the rotor threads, during that part of their rotation which is outwardly toward the intake, have a tendency to reverse the fluid flow and throw it out of the intake, passage, thus impedin entrance of fluid to therotor pockets during rotation of the rotor threads. .It is an object of the invention to provide an'improyedintake passage construction that overcomes vthisobjection and that, furthermore, ,does not interfere with axial admission of fluid wher the intake portis formed for axial as well as radial admission of fluid to the rotors.

Another object of the invention is to provide an improved intake passagefor facilitating radial admissionof fluid to the rotor pockets. At the high speed ofrotation of the rotor members, it

. ;is apparentthatthey are in communication with cross section, -gfrom'the inlet port to the end of the-passage where said passage merges with the end wall and sides of the casing. Thus the momentum of the incoming air tends to force the air into the more confined space formed as the rotor threads approach the casing wall.

Other objects and advantages of the invention will become apparent from the following description when read in connection with the accompanying drawings, in which Figure 1 is a longitudinal, vertical sectional view taken through the axes of the rotary members of the device, with parts shown in elevation;

Figure 2 is a side elevation of the device with the rotor members removed showing the novel fluid intake construction, with parts broken away to show the outlet port; v

Figure 3 is a sectional view taken on the line 3-3 of Figure 2 with the rotors removed; a

Figure 4 is a sectional view taken on the line 44 of Figure 2 with the rotors shown in section;

Figure 5 is a sectional view taken on the line 5-5 of Figure 2 with rotors removed;

Figure 6 is a sectional view taken on the irregular line 6-5 of Figure 3;

Figure 7 is a sectional view taken on the irregular line 'll of Figure 3;

Figure 8 is a sectional view taken on the line 8-8 of Figure 2;

Figure 9 is a sectional view taken on the line 9--9 of Figure 2;

Figure 10 is a sectional View taken on the line ill-40 of Figure 3; and

Figure 11 is a sectional view taken on the line ll--ll of Figure 2.

Referring now to the drawings, particularly to Figure l, the blower includes a housing i6 transversely split into the two housing sections ii and- I2. The housing sections it and ii are rigidly secured together by suitable means, as by the bolts 13, shown in Figure 5, that extend through the mating peripheral flanges i i and 15. The housing It encloses a pair of parall l cylindrical chambers i6 and IT which intersect to form a large common chamber, the cross section of which is substantially in the form of a figure 8.

Mounted for rotation in the housing iii are a pair of meshing helical rotors, a female or gate rotor I8 in the chamber i i and a male or main rotor IS in the chamber H. The main rotor is preferably has two threads while the gate rotor l8 preferably has four, making the ratio one to two. The threads of the main rotor extend through substantially 180 while the threads of the gate rotor extend through substantially 90. A minimum practical clearance is provided between the peripheral envelope of the rotors and the wall of the housing Ill. The profiles of the rotors l8 and i9 may be made in accordance with the disclosure in my United States Patent No. 2,287,716, granted June 23, 1942; wherein the crest edges of the main rotor threads generate the adjacent sides of the gate rotor grooves and the crest edges of the gate rotor threads generate the curved sides of the main rotor threads.

The gate rotor 18 is mounted for rotation in the bearing and bearing carrier assemblies 2% and 2|, received respectively in a sleeve :2 preferably integrally formed with end wall 23 of housing section i! and a sleeve 2 preferably integrally formed with and extending between inner and outer end walls '25 and 28 of housing section :12. The main rotor it is mounted for rotation in the bearing and bearing carrier assemblies 2? and 23,

received respectively in a sleeve 2Q preferably integrally formed with end wall 23 of housing section H and a sleeve 35 preferably integrally formed with and extending between inner and outer end walls 25 and 28 of housing section l2. A minimum practical clearance is provided between the end faces of the rotors i8 and I9 and the housing end walls 23 and 25.

Timing gears 35 and 32 are mounted on the shafts of the gate rotor l8 and the main rotor it, respectively, for synchronizing the operation of the rotors. The drive (not shown) for the rotors is connected to the extended shaft portion 33 of the main rotor is on that side opposite the timing gear 32.

The housing section I! is provided, at its end adjacent the end wall 23 and on one side of a plane intersecting the axes of the rotors l8 and [9, with a discharge passage 3 having an outlet opening 9 and terminating at its inner end in a discharge port 35 formed by relieving adjacent portions of the end wall 23 and side wall of housing section i i, as best shown in Figure 2.

The housing section 22 is provided, at its end adjacent the end wall 25 and on the opposite side of a plane intersecting the axes of the rotors i8 and iii'with an inlet passage 3% having an inlet opening 8 and terminating at its inner end in an inlet port 3? formed by relieving adjacent portions of the end wall 25 and side wall of housing section 52. The peripheral extent of the end wall 2t; is, as best shown in Figure 3, defined by the line connecting points marked a, b, c, d, e, g, and that portion of end wall 25 defined by the line a, b, c, d, e, f, 9, forms an edge of the port 3?.

Now, by looking particularly at Figures 1 and 3 it will be seen that, the space between the edge of the port 3? defined by the line a, b, c, d, e, j, g, and the peripheral envelope of the rotors l8 and it, forms with the outer end wall 26, the side wall of housing section l2 and the outside wall of the sleeves 2t and 39, a chamber 33 that is substantially in the shape of a figure 3 and that provides for axial admission of fluid to the worl ing spaces or pockets bounded by the threads of the rotors l8 and 29 as the pockets pass the port edge a, b, c, d, c, f, 9, during rotation of rotors l8 and I9.

As best shown in Figures 3, 6 and 7, the chamber it constitutes part of the inlet passage 38 and the arrows A and B in Figures 6 and 7, respectively, show the direction of the fluid through the passage 38 axially into the rotor pockets. The terminal portions of the 3-shaped chamber 38 are, as best shown in Figures 1, S and 7, closed by sloping wall portions 35 and Ml joining the innor and outer end Walls 25 and 25. The sloping wall portions 39 and All prevent the formation of eddy'currents and rovide for a free and continuous fiow of fluid into the ends of the rotor pockets.

In order to further direct the fluid into the ends of the rotor pockets a sloping wall portion 4! is provided that joins the inner and outer end walls ticularly to Figure 10 the letters '0, w and :r, y,

z indicate the longitudinal extent of the relieved 7 portion of the side wall of housing i2 and represent edges of port 3?.

The peripheral extent of the relieved portions of the side wall of housing 12 are best'shownin Figures 3 and 4 and extend from g to n and from o to a, and represent theperipheral extent of the port 31. The relieved portions of the side wall of housing [2 included between g, n and 0, a and extending back from the inner end'wall 25 to 12, w and as, y, 2 therefore constitute the portion of port 31 that provides for radial admission of fluid to the rotor pockets.

Walls 42 and 43 of the inlet passage 36 extend in a generally tangential direction from the periphery of the rotors l8 and I9 from the port radially and axially through inlet port 31 to the rotor pockets. 7

Referring again to Figures 3 and 4, it is evident that the portion of chamber 44 included between wall 42 and the peripheral envelope of rotor l8 tapers toward port edge a or in other words in the direction of fluid flow to the pockets of rotor l8, and that portion of chamber 45 included between wall 43 and the peripheral envelope of rotor 19 tapers toward port edge 9 or in other words in the direction of fluid flow to the pockets of rotor IS.

The design of the intake port as set forth above is important in supplying the rotor pockets with a full volume of fluid. Because of the high speed of rotation of the rotors a centrifugal force is created that normally tends to throw the incoming fluid out of the rotor pockets. How-ever, as the rotor l8 rotates from the position shown in Figure 4 in the direction of the arrow, the rotor pocket that is shown communicating with the intake port of passage 36 remains filled since the fluid tending to escape because of the centrifugal action is confined by the wall 42 that forms with the peripheral envelope of the rotor, a chamber of progressively decreasing cross sectional area.

The wall portions 46 and 41 of passage 36, as

best shown in Figures 2, 5, 8 and 9 slope from the inner marginal edge of walls 42 and 43, respectively, inwardly to the periphery of the rotors I8 and I9. These sloping walls 46 and 41 together with the wall portions 5| and 52 bound chambers 48 and 49, as best shown in Figure 5, which form continuations, respectively, of the chambers 44 and 45. By sloping the wall portions 46 and 47, it is apparent that a greater peripheral area of the rotors is opened up to admit fluid to the rotor pockets, and at the same time, these wall portions 46 and 4! guide the fluid into the rotor pockets.

Disposed centrally of the passage 36 and extending longitudinally from the passage walls 46 and 41 to the plane of the housing inner end wall 25, is a wedge shaped deflector member 53. The diverging faces 54 and 55 of the deflector meet in a ridge 56 adjacent the inlet opening 8 of the passage 36, and slope, respectively, toward the walls 42 and 43 of the passage 36 as they extend inwardly thereof. The deflector 53 is preferably integrally formed with the side wall of the housing section l2 and as can best be seen in the sectional views 3, 4 and 5, the wall 51 of the deflector 53 opposite the ridge 56 fits 6 closely the contour of the rotors l8 and I9 with a minimum practical clearance and forms a part of the housing side wall.

The edge defining the junction of the wall 51 and the sloping wall 54 of deflector 53' lies approximately in the horizontal plane passing through the axis of gate rotor l3, while the edge defining the junction of the wall 51 and the sloping wall 55 of deflector 53 lies approximately in the horizontal plane passing through the axis of main rotor l9.

It will be seen, referring particularly to Figure 4, that the deflector 53 directs the fluid through the passage 36 into the chambers 44 and 45 in the direction of rotation of the rotors i8 and [9, the direction of rotation being indicated by the arrows. Rotating in the direction shown, the leading faces of the rotor threads as they emerge from beneath the wall 51 of deflector 53 and travel inwardly away from the inlet opening 8 of the passage 36, they sweep the fluid into the rotor pockets, assurin a full volume of fluid for subsequent delivery to the discharge passage 34.

Again referring to Figure 4, it will be seen that the deflector 53 preventsthe leading faces of the rotor threads, as they travel outwardly toward the inlet opening 3 of the passage 36,

from throwing the fluid out of the passage 35. In other words, without the deflector 53, a portion ofthe fluid enteringflthe passage 36 would be thrown out, and would prevent a full volume of fluid from entering the rotor pockets, resulting in lowered capacity and efi'iciency.

It will be observed, referring particularly to Figure 4, that as a new pocket forms due to rotation of the rotors, this pocket is covered radially by the wall 51 of the deflector 53 but is open axially for admission of air between the outer end of the deflector 53 and the wall 4| as shown in Figure 2. When the rotor threads emerge from under the wall 51, a rotor thread of each of the rotors l8 and I9 being shown in emerging position in Figure 4, the rotor pockets are opened for radial as well as axial admission of air.

The porting arrangement as shown in the drawings provides a device of the compressor type, since the rotor pockets are sealed against communication with both the inlet and outlet ports 31 and 35 for a period of time during rotation of the rotors l8 and [9, in which time the rotor pockets will be reduced in volume as the meshing of the rotor threads advance toward the discharge end of the device. In other words, Opening of the pockets to the outlet port 35 is delayed for a time after the rotor pockets are sealed from the inlet port 31, and the duration of delay determines the degree of compression of the fluid within the pocket before it is discharged. 7

It will be obvious, that the device can readily be converted to eliminate compression of the fluid by extending one or both ports 35 and 31, so that delay in communication between the ports is eliminated, and the invention is of course equally applicable to a device of this type.

I claim: 1. In a fluid device of the character described,

a housing structure including side walls and end walls defining a pair of parallel cylindrical chambers to form a common chamber, adapted to receive intermeshing spiral lobed and grooved rotors cooperating with each other and the housing structure to form fluid pockets that progress from one end of the housing to the other during rotation of said rotors, intake and outlet ports in opposite end portions of said housing, said intake port having portions thereof in both said side and end walls to expose portions of the ends and peripheral envelopes of said rotors, an intake passage provided with wall portions registering with the edges of said housing side and end walls defining said intake port, said intake passage walls extending in a laterally outward direction with respect to the plane common to the axes of said rotors, to provide for admission of fluid therethrough in a radial direction to said rotors, the peripheral extent of the port in said housing side Wall being such as to expose the greater portion of the peripheral envelope of the intermeshed rotors, and the wall portions of said intake passage that register with the longitudinally extending port edges in said housing side wall sloping progressively away from the peripheral envelope of the intermeshed rotors from the last named port edges toward the inlet end of said intake passage, to provide at the inner end of said intake passage between said sloping wall portions and the peripheral envelope of said intermeshed rotors a pair of branching tapered passages for radial admission of fluid to the rotor pockets in a generally tangential direction, the wall portion of said intake passage that registers with the port edges in said housing end Wall being offset in an axial direction with respect to the ends of said intermeshed rotors, and a deflector in said intake passage having a pair of diverging sides disposed respectively to direct radially admitted fluid to said respective branching tapered passages, said deflector being Wholly in that portion of said pas sage radially outward of said intermeshed rotors.

2. Apparatus according to claim 1 in which the deflector is disposed Wholly between planes passing through the axes of the rotors and which planes are normal to the plane common to the axes of the rotors.

JOSEPH E. WHITFIELD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 514,659 Morgan Feb. 13, 1894 1,319,776 Kerr Oct. 28, 1919 1,751,703 Long Mar. 25, 1930 2,243,874 Lysholm June 3, 1941 2,287,716 Whitfield June 23, 1942 2,410,172 Lysholm Oct. 29, 1946 2,425,000 Paget Aug. 5, 1947 2,474,653 Boestad June 28, 1949 2,477,002 Paget July 26, 1949 FOREIGN PATENTS Number Country Date 437,042 Great Britain Oct. 23, 1935

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