US 1795579 A
Description (OCR text may contain errors)
March 10, 1931. Y 1,795,579
ROTARY PUMP Filed April 7, 1927 4 Sheets-Sheet 2 Ilill ug,
VIII/I14 F754 Law/0A5 Eg /2 Byflq fi -(M HTTOENEZS Patented 10, 1931 UNITED STATES PATENT ol-"rics LEONIDAS "P. STOREY, OF ST. PAUL, MINNESOTA, AS SIGNOB OF ONE-BALI TO WATEROU$ FIRE ENGINE WORKS, INC
CORPORATION OF MINNESOTA OBPORATED, OF ST. PAUL, A, A
ROTARY 2m Application filed April 7, 1927. Serial no. 181,752.
This device relates to improvements in ro'-- eliminate the necessity of such troublesome tary pumps, an object of the invention being to obtain a hydrostatic'balance of the pump rotors, in an axial direction, to prevent or 5 reduce friction .between the lateral faces of the rotors or gears and the. pump or pump heads.
The efiiciency of a rotary pump depends 'upon the close adjustment between the lat- 1 eral faces of the gears or rotors and the corresponding opposing faces of the body or of the heads of the pump. Y a f ()rdinarily the rotors are rigidly attached to the shafts, and revolve closely yet freely between the two pump heads, the total lateral clearance being approximately one thousandth of an'inch on each side. This is the running clearance. The shafts are supported in pairs usually attached either to'the pump heads or to the pump body. The hydraulic load is applied at right'angles to the axis of shaft which imposes a load fully radial on the bearings, which thus ordinarily function as radial bearings. However, where ball or 2 roller bearings are used, the end thrust capabilities of these bearings are sometimes utilized in an endeavor to mechanically adjust the rotors of the pump in an axial direction ,to obtain a certain predetermined relief between the lateral face of the pump and the corresponding face of the pumpv or'of the pump heads, thereby preventing or reducing the amount of frictional contact between m The general rule is that the more viscous the liquid the greater the clearance. The necessity for fine adjustment, coupled with the dissimilarity of the materials used in the con struction of the pump create conditions which vary with'changes in temperature and require a complete understanding and considerable mechanical ability on the part of the operator to obtain the proper adjustments. It is'an object of this invention to wear.
pumped. Water requires smaller clearance."
The rotors when left free to assume their own position between the pump heads will tend to drift axially against one of the heads thereby reducing the original clearance to zero on one side and doubling'the clearance on the opposite side. -Under these conditions,
the fluid on the pressure side of the pump is interposed between those faces which provide the larger clearance, resulting inpincreased friction and wear on the opposite face; This lessens the efliciency of the unit, and it is an object of this invention to prevent this end Moreover, when a lateral face of a rotor rubs the corresponding lateral faceof the pump head, no 'lu ricating film is had on the closed side and therefore, considerable friction is had between these faces. In order to counteract such conditions, the device herein provides automatically operable means whereby relief'on each side of the rotor is obtained; This is accomplished by providing means for equalizing the pressures on opposite sides of the rotors orgears. This area of relief is provided by forming recesses in the rotors or heads. By the device herein,
a condition of semihydraulic balance is cre; ated which when supplemented with the fluid filmcaused by the adhesion of the fluid to the revolving rotor, a condition of full hydraulic balance is arrived at, so that both lateral end' faces of the rotor automatically revolve free from metallic contact with the heads.
Objects of the invention are, therefore,-to reduce friction and-, ther efore, wear; to generally increase pump efliciency to increase life ofthe units; to reduce the cost of up-keep to eliminate mechanical adjustment; to pro-' vide a device whichfunctions properly with any and all liquids; which properly functlons regardless of changes of temperature which providesposit ive axial or lateral equihbr um; which eliminates the 'necesslty or Inmute micro-metric adjustments; WhlCh permits the 95 use of dissimilar materials in the manufacture of the pump without in any way affecting the proper operation; which enables a hi her pressure to be maintained, without excee :ng a safe pressure per umt area on any rubbing 10c surfaces; which eliminates the necessity for use of external thrust bearings; which is automatic in adjustment; which functions equally well in singular or multiple-rotor rotary pumps; which does not require external lubrication, and which is safe, simple and cer-' tain in operation.
Features of the invention include all the details of construction of the various forms described, as well as the broader features of the invention which provide means for automatically equalizing pressures on opposite lateral faces of the rotors, and on the delivery side of the pump.
Advantages of the device will be more fully set forth in the description of the drawings forming a part of this application and in said drawings a Figure 1 shows a longitudinal sectional view on the line 11 of Figure 2 illustrating one form of my invention;
Figure 2 is a view with one of the'pump heads removed showing the arrangement of the relief or equalizing passages;
Figure 3 shows a modification of the invention, taken on line 33 of Figure 4, inwhich the relief is obtained across the working faces of the rotors between the teeth;
Figure 4 is an elevation with one of the pump heads removed viewed in a direction indicated by line 4-4 of Figure 3 Figures 5 and 6 are views of another modification in which the faces of the rotors are recessed, this figure being taken on line 55 of Figure 6;
Figure 6 is an elevation viewed in a direction indicated by line 66 of Figure 5 Figure 7 shows another modification in which a single relief passage occupies the upper half and extends entlrely across the faces of the heads. This figure is a section talen approximately on line 77 of Figure 8; an
Figure 8 is an elevation with one of the heads removed, the view being in a direction indicated by line 88 of Figure 7.
The numeral 1 indicates the pump body, 2 represents the intake or suction'port, 3 indicates the discharge or pressure port. The body provides a pump rotor chamber 5, having properl fitted therein the gears or rotors 6, having t eir lobes or teeth 8 in meshed relation and designed in this instance to rotate in a direction of the arrow.
Each rotor is supported by a. shaft 10 which is journaled in the pump heads 16 as castings providing closure for the gear chamber. Each shaft is held in bearings one in each head. The bearings are shown at 2223, the glands -21 have threaded engagementwith lateral tubular extension 26 as stuifing boxes. Suitable packing 27 surrounds the shaft within the tubular space so formed. Bearings 22- 23 are of ordinary 06 ball type. The be 22 is z l by a removable plate 30 and the bearing 23 is capped by plate 31 carr ing a stufiing box 32 as shown. Each sha t 10 has connected thereto a synchronizing gear 35. The function ofthese meshed gears is to properly time the operation of the rotors so that the lobes or teeth are always properlyrelated.
In this form of the device, I provide semicircular depressions 40, two for each rotor, and these depressions are formed in the latn eral faces of the heads, two for each head and face toward the corresponding lateral faces of the rotors. These depressions or passages 40 are arranged on the pressure side of the pump and the pump heads are bored to pro- 89 vide the passages 41 each communicating with a passage 40 substantially as shown. The upper ends of the bores are plugged as at 45. Aligned cross bores 4647 are I provided which connect the pairs of bores 41.
During operation of the pump let it be supposed that the rotors drift into contact, for example with the head 16, the tendency would be to eject the li uid which normally lies between the rotor aces and the opposing faces of the head which would result in a detrimental frictional contact between the surfaces. In addition, inasmuch as more liquid, under these conditions, would tend to enter at the opposite side of the rotors between them and the opposing face of the head 15, the tendency would be to more forcibly engage the faces at the opposite side. However, as the result of semi-circular passages 40, and the ports 4146-47, an equalization of the pressure can take place which balances the rotor in proper relation to the lateral faces of the heads preventing the liquid film from being forced from between the opposing lateral surfaces. If the liquid film has been" momentarily destroyed or ex elIed, the device herein causes such equalization of pressure as will restore the film thus obtaining hydraulic balance. In the design of pump shown in Figures 1 1 and 2, the rotors have comparatively shallow teeth which permits the use of the semi-annular recesses shown at 40. However, the shapes of the rotors vary so that different pressure equalization means are necessary. For ex- 5 ample, if the teeth are long, the body of the rotor may be brought nearer the shaft; in other words, the indentations of the teeth may be of such depth as to materially reduce the lateral face areas of the rotor. For this rea- 1% son, the arrangements shown respectively in Figures 3, 4, 5, 6, 7 and 8 are devised. The forms of the invention shown in these figures would also be applicable to rotors having a solid body and laterally extending blades.
In the form of the invention shown in Figures 7 and 8, the rotor relief extends approximately fifty per cent of the lateral area of the rotors, and'this construction is adaptable to practically all kinds of pumps providing that l I the pump heads. These passages as depresner to obtain Althou h su stantially' the same type of rotor has con shown in all the figures of the drawing, it will be understood that the forms of the invention disclosed in Figures 3, 4, 5, 6, 7 and 8 are particularly designed for use where the rotor has a large lateral face area.
In the form of the device shown in Figures 3 and 4 the passages are provided in a maninter-coinmunication and equalization across the working faces ofthe gears, or between the teeth. 7
In this case radially arranged pockets or passages are provided in the lateral faces of sions facing toward the rotors are indicated at 50. In this instance the fluid can enter the pockets on both sides of the rotors, the intercommunication in this instance being had, as
before stated, across the working face of the rotor. .This is clearly shown in .Figure 4, where it will be seen that certain of the passages 50 are exposed between the rotor teeth and others are hidden behind the teeth.
Figures 5 and6 illustrate a form substantially the same as that illustrated in Figures 1 and 2 with the exception that the rotors themselves are provided on opposite side faces with the passages, as depressions, facing to? ward the pump heads. These depressions are indicated at and are radially arranged substantially in the same manner as those shown in Figure 4. Here an arrangement is provided whereby the depressions or passages 40 communicate with the depressions 55 of the rotors, when these depressions arrive in opposition to the depressions 40.
' In the modification shown in Figures 7 and 8, the faces of the heads or body of the pump are each providedwith a passage which in this instance is. formed by cutting away these surfaces downwardly to a point 61 diametric to and passing through the axes of the rotors. In this case'the clearance is had across the rotor face as in the forms shown in Figures 3, 4, 5 and 6.
The various bores and lateral depressions in the rotors and in thewalls of the pump heads, or in the walls of the pump body may be considered as passages arranged on the discharge side of thepump, between the lateral faces of the rotors and'pump body, and
these passages may in eachcase be viewed as intercommunicating in a manner to. obtain equalization of the hydrostatic pressure at opposite side faces of the rotors and between the lateral faces of the rotors and the corre sponding faces of the pump body or heads. Moreover, these various depressions and bores may be considered as conduits arranged -on the discharge side of the pump in opposition to the lateral faces of the rotors and 65" pump body or heads to provide intercommunicating passages for equalizing the pressure at opposite faces of the rotors.
By inspection of Figure 1, it will be noted that one of the constructional features of the pump is the arrangement of the bearings 22 "so that they are free to move inan axial direction to permit adjustment of the lateral faces of the rotors to maintain the fluid film between these lateral faces and the opposing corresponding faces of the heads. In other Words, the lateral faces of the bearings 22 are free from any axial abutment against the housin so that their movement in a direction axially of the shaft is permitted.
This is done for the reason above mentioned the corresponding conduits of each rotor intercommunicating through the body. a 2. In a rotary pump including a body having' a rotor chamber, intake and discharge passages communicating with the chamber,
rotors Within the chamber located between the passages, and passages arranged on the discharge side of the pump laterally with respect to the engaging faces of rotors and pump body, said last mentioned passages intercommunicating, to equalize pressure at opposite faces of the rotors, and thereacross at points beyond the periphery.
3. In a rotary pump including a'body having-a rotor chamber, intake and discharge passages communicating with the chamber and rotors within the chamber located be-' tween the passages, passages arranged on the discharge side of the pump at the lateral faces of rotors andpump body, said last mentioned passages arranged to intercommunicate at points beyond the working faces of the rotors.
4. In a rotary pump including a body having a rotor chamber, intake and discharge passages communicatin with the chamber, rotors within the chem er located between passages communicating with the chamber,
rotors within the chamber located between the passages, passages arranged on the discharge side of theapump laterally with respect to the engaging faces of the rotors and pump body, said last mentioned passages intercommumcating.
the passages, conduits arran ed on the dis- 6. In a rotary pump including a body having a rotor chamber, rotors in the chamber,
intake and discharge passages communicat- 7 ing with the chamber respectively at opposite sides of the rotors, conduits associated with lateral faces of each rotor to include a substantial area of each rotor face with corre sponding conduits on opposite sides of each rotor intercommunicating at a point beyond the periphery of the rotor.
7. In a rotary pump including a body having a rotor chamber, rotors in the chamber,
' intake and discharge passages communicating with the chamber respectively at opposite sides of the rotors, conduitsassociated with lateral faces of each rotor, and arranged radially to include a substantial area of each rotor face, with corresponding conduits on opposite sides of each rotor inter-communicating at apoint beyond the periphery of the rotor.
8. In a rotary pump including a body having a rotor chamber, rotors in the chamber,
1 c intake and discharge passages communicating with the chamber respectively at opposite sides of the rotors, conduits associated w1th lateral faces of each rotor, on-the pressure or delivery side of the pump and including a substantial area ofeach rotor face, with corresponding conduits on opposite sides of I each rotor inter-communicating at a point beyond the peripher of the rotor.
In witness whereo I have hereunto set my hand this 31st day bf March, 1927.
LEQNIDAS P. STOREY.