US2536638A - Glass-lined pump - Google Patents

Description

Jan. 2, 1951 o. w. GREENE 2,536,638

GLASS-LINED PUMP Filed June 1, 1946 4 Sheets-Sheet 1 INVEN TOR. 0270 h/ Greene Jan. 2, E95 1 0. w. GREENE 2536,38

GLASS-LINED PUMP Filed June 1. 1946 4 Sheets-Sheet 2 INVENTOR. 0/70 A/ GreEne Jan. 2, 1951 o. w. GREENE 2,536fi38 GLASS-LINED PUMP Filed June 1, 1946 4 Sheets-Sheet 3 ijwulil' IN V EN TOR.

B'Y WA 0. W. GREENE GLASS-LINED PUMP Jan. 2, 151

4 Sheets-Sheet 4 Filed June 1, 1946 INVENTOR. v 0770 WGr'ee/w Patented Jan. 2, 1951 GLASS-LINED PUMP Otto W. Greene, Rochester, N. Y., assignor to The Pfaudler Company, a corporation of New York Application June 1, 1946, Serial No. 673,850

15 Claims.

My invention relates to pumps and more particularly to pumps of the centrifugal or rotating impeller type suitable for use in the pumping of chemicals.

While the pump of my invention has primarily been developed for use in handling metal-attacking chemicals,'the principles thereof may be employed in the pumping of other liquids as. for example, where the liquid being pumped is substantially chemically inert insofar as attackin metals, but of a viscous character and likely to solidify on the walls of the pump, or of such nature that it is subject to contamination requiring that the pump be frequently cleaned. Notwithstanding the fact that glass is substantially impervious to almost all acid chemicals, insofar as I am aware, no one has successfully produced a commercially practical glass-lined pump.

Many reasons probably exist for this. One of these exists in the problem encountered when glass is employed, of properly balancing and supporting the glass-coated rotor or impeller.

Another exists in the problem of preventing access of the liquid being pumped to the drive shaft and the stuillng box. Still another exists in the securing and maintaining of adequate clearance between the rotating impeller and the sidewalls of the enclosing casing, necessitated by reason of the frangible character of glass and distortion under the heat of fusing the glass. Other conditions, not heretofore adequately provided for. exist in the securing of adequate and positive lubrication, and in the proper support and mounting of the pump to enable quick and easy dismantling thereof for the purpose of draining and cleaning the casing.

An object of my invention is to provide an improved and commercially practical glass-lined pump, which may be built at reasonable cost, and in which all the parts exposed to the corrosive action of the liquid being pumped are coated with lass.

Another object of my invention is to provide a pump for use in conveying liquids under temperature or pressure or both wherein a fluid, preferably an inert gas, is introduced into the casing under pressure at such point that and the casing is arranged so that the liquid being pumped is separated, or walled off by the inert gas, and the liquid is thereby prevented from gaining access to the stuiiing box and the drive shaft.

Another object of my invention is to provide a pump suitable for use in handling chemicals, wherein all the parts exposed to the liquid being pumped are coated with glass, and wherein means are provided for supporting and mounting the pump drive shaft and the pump impeller in a rigid plane of rotation, together with means for adjustably supporting the pump casing about the impeller so that the clearance between the casing and the rotating impeller unit may be adjusted without disturbing the rotating impeller unit or its drive shaft from its fixed, rotatably supported position.

My invention further contemplates a vertically mounted glass-lined chemical pump wherein the lower half of the pump casing may be quickly and easily disconnected from the upper half for the purpose of enabling access to the pump casing and impeller for the purpose of cleaning and draining the casing.

other objects and advantages of my invention I will be set forth in the appended claims and will be clear from the following description, when taken in connection with the accompanying drawings, in which:

Fig. 1 is an external perspective view of the chemical pumping unit of my invention, and showing the vertical adjustable mounting thereof and the drive therefore;

Fig. 2 is a vertical view of the chemical pumping unit with half of the unit shown in section;

Fig. 3 is an enlarged sectional view of a portion of Fig. 2 showing, in detail, the means for sealing the casing and protecting the stuflin box;

Fig. 4 is a front elevation with parts cut away showing the means for supplying lubricant to the stuffing box, and the means for supplying a fluid to the pump casing under pressure for the purpose of protecting the stuiling box and drive shaft;

Fig. 5 is a sectional view through the impeller hub looking down upon the blades, illustrating how the impeller is balanced. and showing how the blades are made alternately wide and narrow;

Fig. 6 is an enlarged sectional view of a portion of Fig. 2 showing how the lower half of the casing is releasably locked with respect to the upper half thereof;

Fig. 7 is a fragmental end elevation of the locking ring;

Fig. 8 is a fragmental top plan view thereof;

Fig. 9 is a view of a modified form of means for releasably locking the lower half of the casing with respect to the upper half, together with a, self sealing gasket, the arrangement being particularly adapted for use when more severe chemical service is encountered; and

Fig. is a sectional view showing one of the adjustable supports for the casing.

The chemical pump of my invention (Fig. 2) comprises a main casing part II, a cover part 12 and an impeller or rotor It. The impeller is connected to a drive shaft 14, in a maner presently described, which has mounted in driving relation at the upper end thereof (Fig. 1), as shown at ll, a multi-grooved pulley for the reception of v belts or any other suitable type of drive, indicated by the numeral H. The belts of the drive are arranged in driving relation with a grooved pulley I8 carried by a shaft (not shown), which is connected to a driving motor. The driving motor (not shown) is mounted on the rear of a support bracket It.

One of the important features of my invention lies in the fact that the unit is mounted vertically to facilitate the cleaning and draining of the pump when the suction pipe 2| and the cover plate l2 have been removed. This vertical arrangement is particularly important if the pump is employed for handling viscous liquids or other materials likely to solidify or agglomerate on the walls of the casing such as rubber latex, or if the pump is to .be used to convey various chemicals. Thorough cleaning and draining of the unit is essential where the pump is used for handling a second chemical likely to be contaminated by any residue remaining in the casing from the first liquid pumped. The vertical mounting of the unit is also important for other reasons as will presently appear.

To facilitate the vertical mounting of thepump unit, the main part II of the pump casing is carried by a support 22 which is preferably rigid with a main frame 23. The main frame is carried by side stands 24 with the pump suspended therebetween so that the unit is supported a suitable distance above the floor level to provide space to enable the cover plate 12 to be conveniently removed and dropped downward. The vertical suspension of the pump casing, in the manner above described, enables the independent adjustment of the pump casing with respect to the impeller for .the purposes which will presently appear.

The drive shaft I 4 extends vertically upward (Fig. 2) and has fixed thereto a shaft-wearing sleeve 26, the shifting of which upwardly along the shaft is limited by a shoulder ring 21 (Fig. 3) fitted to the shaft. The impeller has a hollow central hub 28, which has a bore 29 at its upper end in which a keyway 3| is cut. The impeller hub is connected to the drive shaft H by means of a Woodruif key 82 fitted to the keyway 3|, as shown most clearly in Fig. 3. The lower end of the drive shaft extends into a bore formed in the hub.

The lower end of the shaft sleeve 26 is provided with an annular recess 33 adapted to receive resilient packing 24 against which the annular end 26 of the hub of the impeller is adapted to seat so as to lock the packing in the recess. The drive shaft has a bore, as shown at 21. and extending internally and concentric with the shaft is an elongated stud 38 which is threaded into the casting forming the hub of the impeller, as shown at 39. The upper end of the stud projects through the shaft and is threaded to receive a nut 42, the lower face of which engages the end of the drive shaft, as shown at 42. The upper end of the elongated stud is provided with a wrench-receiving head 43 by means of which the elongated stud may be amass threaded into or out of the hub of the impeller in the manner shown at 39.

It will now be appreciated, upon threading the stud securely into the hub of the impeller and tightening down upon the nut ll against the end of the drive shaft so as to apply a pull in pressure, that since the movement of the shaft-wearing sleeve 26 with respect to the shaft is limited, the entire impeller may be drawn upward along the drive shaft so that the end 36 of the hub will seal against the packing 34. It will, moreover, be apparent that the impeller is fixed in assembled relation with respect to the shaft and the shaftwearingv sleeve, and that access of the liquid being pumped to the drive shaft is prevented by the seal formed between the end of the impeller hub and the lower end of the shaft sleeve. Moreover, access of the liquid being pumped to the hollow impeller hub is prevented.

The entire inner walls of the pump casing, as indicated at 44, are provided with a coating of glass or other vitreous materials which is impcrvious to almost all acid chemicals. Moreover,

each of the impeller blades together with the hub of the impeller is similarly provided with a glass coating, as indicated at 46, so that all parts of the pump exposed to the liquid being pumped are protected against corrosive action by the chemicals being pumped (except as will later appear).

The processes for applying the glass coating to the casing-and impeller, which may be of castiron or any other suitable metal, are well known. The cast-casing and impeller give the unit the necessary mechanical strength to withstand the pressures and shocks encountered. The glass surfaces may be easily cleaned with water or, in case the chemicals pumped are not soluble in water and tend to adhere to the glass walls, suitable solvents other than water may be employed without injuring the glass coating.

As shown most clearly in Fig. 1, bolted to the main frame 23 is a bearing shell 66. The bearing shell extends in surrounding relation with the drive shaft and has mounted therein a plurality of ball bearing assemblies 61. The bearing is provided with a ca 68 and a nut 69 is threaded on the lower end thereof. Since the bearing per se constitutes no part of my present invention, it will not further be described.

A stuihngbox ll extends in a concentric relation with the shaft sleeve 26, as shown most clearly in Figs. 2 and 3. The stumng box of a chemical pump is one of the greatest sources of pump failure due to attack by the chemicals on the packing and lubrication of the stufhng box. This difllculty I have overcome in a practical and novel manner as will hereinafter appear. Mounted in the stuffing box is a bearing assembly comprising rings 13, which have conical bearing surfaces 14. A cylindrical bearing element 18 is provided with cooperating conical bearing surfaces. The bearing serves to support and steady the drive shaft, minimize the load on the packing, and acts as a lantern lubricator to distribute lubricant. On

opposite sides of the bearing, the stuffing box is provided with rings of packing, which may be compressed by means of a packing gland, generally indicated by the numeral 11.

The packing glandcomprises a plurality of semi-cylindrical elements 18 extending around the shaft sleeve and which are engaged by a cap 19. Adjustable screw assemblies 8| are threaded into the end of the stuiling box casting and apply,

by means of springs, a yielding adjustable pressure on the stufllng gland and the packing. The packing employed may be of any suitable type in accordance with the conditions encountered but preferably an asbestos packing is used because asbestos is chemically substantially inert and suitable for either high or low pressures. For the purpose of enabling distribution of lubricant to the packing the bearing elements I3 and IQ are suitably grooved (not shown) for the reception of the lubricant, which is supplied to the stufling box in a manner presently described.

The main casing part II is provided with an opening through which the drive shaft for the impeller extends and is provided with a flange 83 adapted to receive a cooperating flanged collar 84. The lower end of the stufiing box is provided with a flange 86 and a suitable gasket I1 is interposed between the flange 83 of the casing and the flange 86 of the stuffing box. The gasket is compressed to form a seal between the facing surfaces of the flanges and the stufling box is held in rigid assembled relation with the pump casing by bolts, which extend through the flange 86 into the collar 84 (Fig. 1).

With the above described arrangement of stufiing box, upon removal of the bolts and loosening the packing gland, the entire stufling assembly may be lifted upward so as to enable access to the stufling box for removing hardened or worn packing and inspection of the shaft sleeve. By the use of a suitable gauge, the stufilng box may be reassembled with respect to the casing in concentric relation with the shaft sleeve. It will be particularly noted that the position of the drive shaft is fixed when the elongated stud is pulled in; that the stufling box is independently adjustable with respect to the drive shaft; and that the stufllng box is supported entirely by the pump casing.

Another of the problems encountered in the manufacture of a glass-lined pump arises in connection with the impeller blades and the assuring of clearance between the blades and the pump casing without undue loss in efficiency. This problem arises due to warpage and distortion unavoidably encountered during the application of the vitreous coating to the impeller. Only three impeller blades can be held in one rotational plane when distortion or warpage during the application of the glass coating has occurred.

In the drawings I have shown an impeller having six blades and I prefer, for reasons of efllciency, this number of blades. As will clearly appear from an examination of the blade sections of Fig. 5, the alternate blades are wide and narrow; the three wide blades being those which can be brought true to a rotational plane in the final machinin of the internal bore of the impeller. Briefly the method employed of making the impeller comprises first rough grinding the casting. The impeller is then assembled with respect to a special conical wood faced face plate which engages the three wide blades. After centering in the lathe the casting is turned and later ground and brought to balance. The heating is then glass coated and during this operation some distortion is impossible to avoid. However, the impeller is reassembled with respect to the wood face plate with the three wide blades in contact therewith. The hub of the impeller is then bored with the axis of the bore normal to the rotational plane of the blades. By making the intermediate blades narrower, an allowance is made for some distortion or these intermediate blades. With 0 distortion of the intermediate blades allowed for. clearance between the blades of the impeller and the casing walls can be secured in final assembly.

In addition to the problem of providing impeller blades, which will rotate in a true path of travel, the use of a glass coating on the casing walls and the impeller blades makes it impossible to employ conventional methods of providing for clearance between the casin walls and the rotating blades. This is frequently accomplished in conventional pumps by grinding the casing wall or impeller. Adequate clearance is extremely important for the reason that if the agitator blades should strike the casing sidewalls, chipping and breaking of the glass will occur exposing the metal, which will result in early failure in service. Because of this necessity of insuring adequate clearance, I have provided novel means for adjustin the pump casing with respect to the impeller. This enables the impeller and its drive shaft to be rigidly located and pulled in, as described above, and the adjustment of clearance to be accomplished without disturbing the impeller or drive shaft.

As shown in the drawings (Figs. 1 and 10) the main casing part II is provided with three upwardly projecting bosses 9|, each of which has a threaded bore 92. A stud S3 is threaded into each of the bores and extends through a threaded bore formed in the support plate 22. A nut 94 is threaded on the upper end of each of the studs 93, and engages a jack-screw it. The jack-screw 96 is provided with external threads 91 which cooperate with the threaded bore of the support plate 22. A pair of lock nuts 99 are threaded on the jack-screw, one On each side of the support plate 22. A wrench-receiving element is provided on the jack-screw by which the Jack-screw may be turned to thread the jackscrew into and out of the support plate.

When it is found, upon examination in a manner which will presently be made clear, that the clearance between the main casing part and the impeller blades is insufficient or toogreat, the main casing part may be raised or lowered, as required, by loosening the nut 94 and the lock nuts 99. After the clearance has been properly adjusted, the nuts are tightened against the support plate and the main casing part is then properly positioned and rigidly supported with respect to the impeller. If it is determined upon examination that the casing is cocked with respect to the impeller, one or more of the jackscrews may be adjusted until the clearance over the blades is uniform.

I have provided novel means for testing or determining the clearance between the impeller blades and the casing. Such meansmay comprise a loop or wire of a diameter in accordance with the desired clearance. For example. if it is desired that a one-sixteenth clearance be provided, a one-sixteenth inch diameter wire would be used. The, clearance wire has its ends fastened in a handle I01. To test the clearance, the clearance wire or gauge is inserted in the suction opening, as indicated in Fig. 2, and passed between the lower edges of the blades and the cover plate l2, and also ilooped over the ends of the blades and passed between the upper edges of the blades and the main casing part I I. As previously mentioned, three of the blades are adjusted in the final boring;operation so that they revolve in a true rotational plane. Moreover, the parts of the casing adjacent the blades are accurately 7 machined prior to fusing the glass and the methodemployed minimizes the efiects of distortion at the surfaces adjacent which the blades run. With the three wide blades rotating in a true plane and with the adjacent surfaces of the easing held true, substantially uniform clearance can be obtained over the blades by accurately ad- Justina the casing with respect to the impeller as'previously described.

The blade clearance should be tested, rotating the impeller by hand, each time any adjustment oi'wthe pump is made and before the pump is started, as it is essential that the glass surfaces of the blades or casing be not abraided or broken so as to permit access of the chemicals being pumped to the metal of the casing or blades. Itwill thus be apparent that I have provided novel means for not only adjusting the casin with respect to the rotating impeller, but also have provided novel means for testing the clearance and insuring that, in operating, the blades will not engage or strike against the casing sidewalls.

One. of the problems encountered in making a glass-coated pump impeller is that of securing accurate balance of the impeller. The usual method with metal impellers is to grind or file the impeller and the blades thereof until accurate balance is obtained. This method of balancing is impossible with a glass-coated impeller, nor is it possble to balance the impeller prior to the application of the glass coating with any assurance that, after the coating has been applied, the impeller will remain in balance. Not only is some distortion impossible to avoid but alsothe glass coating cannot be applied to a uniform thickness. In the pump of my invention, the balancing of the impeller is accomplished in a novel manner.

During the preliminary machining prior to the application of the glass coating the impeller is brought into approximate balance. Within the impeller hub, as shown most clearly in Fig. 5, I have provided a series of ribs I08, which extend preferably radially of the hub along the general lines of the blades. The ribs terminate short of the inner sidewalls I09 of the hub so as to provide a recess between the end of each rib and the inner sidewall of the hub.

One or more impeller balancing elements may i then be positioned between the ends of the ribs and the inner sidewalls of the hub. In Fig. I have shown one of the impeller balancing elements III in position. These balancing elements preferably comprise a rubber center of somewhat cylindrical shape, which is provided with an exterior lead sleeve. The impeller balancing elements may be then calked in position and will be distorted in the calking so as to shape themselves, as shown in Fig. 5, in accordance with the space available and be locked between the ends of the ribs and the inner sidewalls of the hub.

It will be appreciated that any number of balanction I have provided novel means for preventing the chemicals being pumped from gaining access to the stufiing box and shaft. In accordance with this phase of the invention, such means are part of, or operatezin cooperation with, the stumng box lubrication system.

The system is rovided with 9. preferably cylindrical lubricator IIIi, shown most clearly in Fig. 4, having a reservoir III for the reception of the lubricant. Preferably the lubricant employed is a good grade of mineral oil. The lubricator is provided with a window II8, through which a tube II9 extending into the lubricator is visible. The tube extends upward and projects from the lubricator through a fitting I2I and is connected by a fitting I22 to a tube I23. The tube or line I23 is provided with a globe or shut-oil valve I24 and a needle valve I26.

The line I23 is connected to a source of gas under pressure. Preferably an inert gas is employed, which will not corrode the metal parts with which it contacts nor have a deleterious effect on the lubricant. The source of gas is maintained at a higher pressure than will normally be required in the system; the exact amount of gas to balance the system required for the particular conditions encountered being regulated by the needle valve I26.

When the system is in operation, the inert gas is supplied through the tube H9 and bubbles upward through the lubricant, as indicated in Fig. 4.

This gives a visible indication that the system is in operation. The gas passes upward to the top of the lubricator through a connection I21 surrounding the tube II9 into the fitting I2I. The fitting I2I is connected by a line I28, and fittings I29 to a glass-walled tube or sight glass II. The sight glass I3\ is suitably sealed and supported in position by means of end plates I32 and tie rods I33 connecting the end plates.

The casing is provided with an opening I34 adapted to receive, in fluid tight arrangement, a fitting I36, which is connected to the sight glass as shown. By this arrangement, the inert or scavenging gas is supplied to the impeller casing under pressure and this pressure may be regulated by the needle valve I25 Lubricant is supplied to the reservoir I I"! through a fitting I, which may have a valve I42 therein, and any desired lubricant coupling I43 adapted to receive a lubrication pump may be employed. Lubricant, under the pressure of the gas supplied tothe reservoir II'I, flows through a line I to'a valve controlled fitting I46 (Fig. 2). The fitting I46 is connected through a bore I50 in the stuiilng box wall to a recess I formed in the bearing 13, 15.

It will be particularly noted that the opening I34 into the pump casing is remote from the ends of the blades of the impeller and is as close as possible to the hub thereof. The annular cone shaped space around the hub of the impeller is filled, during operation of the pump, with the scavenging gas supplied thereto, which is at a pressure sufficient to balance the liquid being pumped at the pressure thereof existent adjacent said cone shaped space. The pressure developed by a centrifugal pump increases in accordance with the square of the distance from the axis of the impeller. Thus, the gas pressure adjacent the annular space around the hub is considerably less than the pressure developed by the pump in the volute space I56 surrounding the impeller. For example, if the pressure developed by the pump is fifty pounds, it may be necessary to supply scavenging gas under a pressure of only ten pounds in order to balance or wall of! the fluid pumped and prevent it from gaining access to the stufling box.

It will be particularly noted that the hub of the impeller is closely spaced with respect to the wall of the main part of the casing II along the line I46. This close spacing of the parts forms an annular dam, which assists in preventing the liquid being pumped from entering the space above the darn. Preferably the scavenging gas pressure is regulated so that the darn approximately marks the line of separation between the scavenging gas and the liquid.

The action of the system on the fluid pumped and the scavenging gas is similar in some respects to that produced by a centrifuge. That is, the liquid pumped, being heavier than the gas, is thrown outward by the impeller. The lighter gas tends to "float" on the liquid nearer the center of rotation. Moreover, it will be noted that the space into which the gas flows is above the liquid, and thus gravity assists'in the action. The entire space surrounding the hub of the impeller is filled with the scavenging gas, forming a wall of inert gas, which prevents the liquid being pumped from gaining access to the stufling box. Under certain conditions of operation, the fluid in the space above the dam may be a frothy mixture of gas and liquid. However, the fluid adjac t the stuffing box is primarily or wholly a gas, ecause of the tendency of the lighter gas to rise and the centrifuge effect of the rotating impeller.

Lubricant flows to the stufling box through the line I44 and through the lubricant grooves provided in the bearing 13, 16. This lubricant is under a pressure slightly greater than that of the scavenging gas by reason of the fact that there is a head of liquid on the stufling box determined by the height of the surface of the liquid in the lubricator II6 above the stuffing box. This excess pressure is sufficient to insure that whatever leakage occurs is a leakage of lubricant through the stufling box into the pump. However, preferably thestatic head or pressure by which the pressure of lubricant exceeds that of the scavenging gas in the casing, is just approximately the amount of pressure required to overcome the resistance to the flow of lubricant and to force lubricant through the bearing lubrication grooves and through the packing. When properly arranged, the pressure of lubricant at the bottom of the stuffing box approximately balances the gas pressure within the pump casing so that no appreciable leakage or flow occurs in either direction.

In practice with the pump developing the desired pressure, the needle valve I26 is set so that no liquid is visible in the sight glass I3I. If liquid is visible in the sight glass, it is an indication that the gas is not reaching the casing because it is not at a pressure high enough to counterbalance the pump pressure. Upon opening the needle valve I26, the pressure of gas and also the pressure of lubricant will be increased so that the scavenging gas will force the fluid being pumped out of the sight glass I3I and occupy the space in the casing surrounding the hub of the impeller.

In a chemical pump, it is essential that the pump be capable of being thoroughly and quickly cleaned particularly when the liquid is pumped at an elevated temperature and tends to solidify when cold. With the pump of my invention after the suction pipe 2| has been removed, the lower half or cover of the casing may be quickly disconnected from the upper half and dropped downward to permit draining and cleaning of the casing. The suction pipe 2I is coupled to the suction of the pump by means of a pair of flanged rings I5I (Fig. 2) and I52 (Fig. 1), which are bolted together. The annular end of the suction of the pump is flanged, as shown at I53, to receive coupling element I5I and the end of the suction pipe is similarly flanged (not shown) so as to receive the coupling element I52. Packing I54 is inserted between the flange of thesuction pipe and the flange of the pump suction, which is compressed to form a seal when the coupling halves I5I and I52 are bolted together. The volute I56, wherein the kinetic energy imparted by the impeller is converted to pressure, is connected to a discharge pipe I (Fig. 1)

The quick locking and releasing means or breach lock for the two halves of the casing comprises an annular cylindrical ring I58 (Fig. 1), which extends around the periphery of the two halves of the casing. The ring has a lip I (Fig. 1) which extends around the ring, and engages an annular machined surface formed on the main part II of the casing. The ring is provided with a cut-out I59 into which project the teeth of a rack I6I. The rack is cut on the arc of a circle and is bolted, as indicated at I62, to the upper half or main part I I of the casing. The annular ring I58 is provided with a boss I63, which has a bore I64 (Fig. 6). A pinion I66 has its lower end journaled in the bore and the teeth thereof mesh with the teeth of the rack, as shown in Fig. 6. The lower end of the pinion has a groove or notch I68 cut therein, in which is seated the end of a set screw I69 for holding the pinion in its seat.

The lower periphery of the annular ring I58 has inwardly turned teeth I1I, which extend entirely around the inner circumference thereof. The lower face of the casing is provided with an annular flat surface I12 adapted to receive an annular ring I13, shown most clearly in Figs. 7 and 8. The annular ring I13 is bolted to the annular face I 12. The outer circumference of the annular ring I13 is provided with a plurality of cut-out notches I14, which correspond in number and location to the teeth I1I of the annular ring I56. interposed between each of the cutouts I 14 is a projection I16, which has an inclined cam surface adapted to cooperate with the teeth I1I to lock the halves of the casing together, and apply pressure between-them.

An annular ring of packing I11 lies in annular pocket formed between the casing halves so that when pressure is applied between the halves of the casing the packing is compressed and spread into this groove so as to securely seal the parts.

It will now be appreciated that when the parts are assembled, as shown in Fig. 6, that by applying a wrench to the wrench-receiving part I 8| of the pinion I66, the pinion will turn on the rack so as to rotate the annular ring I58 about the casing. This rotation shifts the teeth I1I with respect to the projections I16 so that the teeth register with the cut-outs I14 of the annular ring I13. When the teeth I1I 'are in registry with the cut-outs I14 the lower half of the casing, together with the anular ring I13, is free to be dropped downward.

When disassembling the casing, blocks should be positioned below the lower half of the casing for receiving the casing and preventing a jar likely to damage the glass inner wall. Upon removal of the cover or lower half of the casing, the casing may be drained and cleaned. Ii. de-

sired, when cleaning the casing, the pump impeller may be removed by loosening the nut I and unthreading the pull rod by applying a special tool to the her .1 43. Because of the quick and easy operation of the breach lock, the casing may be frequently and thoroughly cleaned without undue interruption of operations, which is essential, for example, if the pump is to be used for pumping different chemicals or if viscous liquids are handled.

After the pump has been cleaned, it may be quickly reassembled by the reverse of the operations, above described. When the teeth III engage the cam surfaces of the annular ring I13, continued rotation of the annular ring I58 applies pressure on the casing parts and on the packing I" to seal the annular joint between the two halves of the casing.

The above described breach lock is suitable for use when the pump is to be used for moderate chemical service. However, when severe chemical service is encountered I have found the casing lock, shown in Fig. 9, more satisfactory. The arrangement shown in Fig. 6 conceals any leakage which may develop and for this reason is not preferred when corrosive chemicals are being pumped. In arrangement of Fig. 9 each half of the casing is provided with an annular lip I81, which has a rounded cam surface. A plurality of locking elements, generally indicated by the numeral I88, are spaced around the periphery of the two halves of the casing. These locking elements I98 comprise a bolt I89 having a head I9I. A pair of clamps I92 are mounted on each of the bolts, each clamp having a down turne'd cam surface I93. A nut I9 is threaded on the end of each of the bolts and by drawing up on the nuts I94, the cam surfaces on the casing and the cam surfaces on the clamps are caused to cooperate to apply pressure between the halves of the casing.

When highly corrosive chemicals are encountered, making it desirable to use this type of casing lock, I have found two rings of packing I96, I91 more satisfactory. The packing I96 is of a material that is resistant to the particular chemical being pumped and may be somewhat porous. The packing I91 forms the seal to prevent leakage of the corrosive liquid which would be likely to corrode the locking elements I88. For the purpose of receiving the packing I96 each half of the casing is provided with a substantially flat surface I98 and an annular groove I99 for the reception of the packing I91. It will be particularly noted that the pressure developed by the pump tends to wedge the packing in position and increase the effectiveness of the seal.

While the casing lock, shown in Fig. 10, is less satisfactory than the breach lock above described from the standpoint of not being capable of as rapid application and removal, it may be employed for maintaining a seal between the halves of the casing under extremely severe chemical conditions. It will be particularly noted that with both sealing arrangements, pressure is applied on the packing so as to squeeze the packing and seal the annular parting between the two halves of the casing. In both arrangements shown for locking and sealing the two halves of the casing, the locking elements are applied externally of the casing. They are thus removed from contact with the chemicals being pumped and hence the possibility of corrosion thereof is minimized.

12 While I have shown and described the pre ferred form of my invention, it will be appreci-.

ated that various changes and modifications may be made, particularly in the form and relation of parts, without departing from the spirit of my invention as set forth in the appended claims.

I claim:

1. A pump of the character described comprising, in combination, a casing, an impeller having a hub mounted in said casing, a stuffing box, said casing having a chamber extending around the hub of the impeller, a shaft extending through the stuffing box into driving relation with the impeller, means forming a seal adjacent the end of the hub of the impeller for preventing access of fluid to the shaft, means forming a seal between the casing and said stuffing box to prevent leakage of fluid externally of the pump from said chamber, means for supplying lubricant to said stuffing box under pressure, and means for supplying an inert gas to said chamber under a pressure which bears a relationship to the pressure of the liquid being pumped and the pressure at which lubricant is supplied to said stuffing box.

2. A pump of the character described comprising, in combination, a casing, an impeller having a hub mounted in said casing, a stuffing box, said casing having a chamber extending around the hub of the impeller, a shaft extending through the stufling box into driving relation with the impeller, means forming a seal adjacent the end of the hub of the impeller for preventing access of fluid to the shaft, means forming a seal between the casing and said stuffing box to prevent leakage of fluid externally of the pump from said chamber, means for supplying lubricant to said stuffing box under pressure, means for supplying a fluid under pressure to said chamber, and means for regulating the pressure of said fluid and the pressure of said lubricant.

3. A pump of the character described comprising, in combination, a casing, an impeller having a hub mounted in said casing, a stufllng box, said casing having a chamber extending around the hub of the impeller, a shaft extending through the stufling box into driving relation with the impeller, means forming a seal adjacent the end of the hub of the impeller for preventing access of fluid to the shaft, means forming a seal between the casing and said stufling box to prevent leakage of fluid externally of the pump from said chamber, means for supplying lubricant to said stufling box under pressure, means for supplying a fluid under pressure to said chamber, means for regulating the pressure of said fluid, and means applying the pressure of said fluid on said lubricant to force lubricant to said stufling box under a pressure which bears a fixed relationship to said fluid pressure.

4. A pump of the character described comprising, in combination, a pump casing, an impeller having a drive shaft, a stufling box through which said shaft extends, means for supplying lubricant to said stufling box comprising a chamber connected to said stuffing box and having lubricant therein, means for supplying a gas to said chamber to maintain the lubricant supplied to the stuffing box under pressure, and means for supplying gas from said chamber to said casing at a point such that said gas ac- 13 cumulates in the casing between the liquid being pumped and the stufling box.

5. A pump of the character described comprising, in combination, a casing including a main casing part and a cover part having a suction opening, an impeller having blades and a hub, a drive shaft extending into said hub and slidably keyed with respect thereto, a sleeve fixed to said drive shaft, a rod extending through said drive shaft and fixed to the hub of the impeller, a sealing element between the end of the hub and said sleeve, means for pulling on said rod to draw said impeller along said shaft and thereby compress said sealing element between the end of the hub and said sleeve, a stuffing box extending concentric with the shaft, means including a sealing element for drawing the stufflng box into sealing relation with the main casing part, means including a plurality of adjustable elements for supporting and for adjusting said main casing part and said cover part with respect to the plane of rotation of the blades so as to provide clearance around the blades after the impeller has been fixed in position, and means including an opening in the main casing part communicating with the rearward side of the impeller for admitting a fluid under pressure to said casing to prevent access of the liquid being pumped to said stufiing box.

6. A pump of the character described comprising, in combination, a pump casing, an impeller mounted in said casing, a stufiing box, a shaft extending through said stufiing box into driving relation with the impeller, means for preventing the liquid being pumped from gaining access to the stufiing box comprising a chamber between the impeller and the stufling box, said chamber being sealed except for having access to a pressure point in the pump casing and said stuffing box, and means for supplying a fluid to said chamber under a pressure such that it substantially balances the pressure of the pump at the point to which the chamber pressure has access.

7. A pump of the character described comprising, in combination, a pump casing comprising castings having glass coated inner walls, an impeller comprising a casting having glass coated vanes mounted in said casing, a stuffing box, a shaft extending through said stufling box into driving relation with the impeller, means for preventing the liquid being pumped from gaining access to the stufling box comprising a chamber between the impeller and the stufiing box, means for supplying an inert fluid under pressure to said chamber, and means for regulating the pressure of said fluid to a pressure such that the liquid pumped cannot gain access to the stufiing box.

8. A pump comprising, in combination, a pump casing having an opening, a drive shaft extending through said opening, an impeller mounted in said casing having a hub spaced from the inner wall of the casing, a stuffing box having packing therein, means for preventing the liquid casing having an opening, a drive shaft extending through said opening, an impeller mounted in said casing having a hub spaced from the inner wall of the casing, a stufling box having packing therein, means for preventing the liquid being pumped from gaining access to the packing of the stufling box comprising a connection extending through the wall of the casing into the space between said hub and the casing, means for supplying a fluid under -pressure through said connection to provide a'barrier oi fluid under pressure in said space between the liquid being pumped and the packing in said stuiling box, means between said stufllng box and the margins of said opening for forminga seal, and'means between'said hub and the drive shaft for forming a seal.

10. A structure of'the character described comprising, in combination, a casing, a driven element mounted in said casing, a stufling box, a shaft extending through the stufling box into .driving relation with the driven element, said casing having a chamber extending around the shaft adjacent the stufling box, means forming a seal for preventing access of fluid to the shaft, means forming a seal between the casing and said stufiing box to prevent leakage of fluid externally of said chamber, means for supplying lubricant to said stufiing box under pressure, means for supplying a fluid under pressure to said chamber, means for regulating the pressure of said fluid, and means for applying the pressure of said fluid on said lubricant to force lubricant to said stufling box under a pressure which bears a fixed relationship to said fluid pressure.

11. A structure of the character described comprising, in combination, a casing, a driven element having a drive shaft, a stuffing box through which said shaft extends, means for supplying lubricant to said stuffing box comprising a chamber connected to said stufling box and having lubricant therein, means for supplying a gas to said chamber to maintain the lubricant supplied to the stufflng box under pressure, and means for supplying a gas from said chamber to said casing at a point such that said gas accumulates in the casing between the liquid in the casing and the stufiing box. 4

' 12. A pump of the character described comprising, in combination, a casing, an impeller having a hub mounted in said casing, a stufling box, said casing having a chamber extending around the hub of the impeller, a shaft extending through the stufling box into driving relation with the impeller, means forming a seal adjacent the end of the hub of the impeller for preventing access of fluid to the shaft, means forming a seal between the casing and said stufling box to prevent leakage of fluid externally of the pump from said chamber, means for supplying lubricant to said stuffing box under pressure, and means for supplying an inert gas to said chamber under a pressure which bears a relationship to the pressure of the liquid being pumped and the pressure at which lubricant is supplied to said stufling box.

13. A pump of the character described comprising, in combination, a casing including a main casing part and a cover part having a suction opening, an impeller having blades and a hub, a drive shaft extending into said hub and slidably keyed with respect thereto, a sleeve fixed to said drive shaft, a rod extending through said drive shaft and fixed to the hub of the impeller, a sealing element between the end of the hub and said sleeve, means for pulling on said rod to draw 1d said'impeller along said shaft and thereby compress said sealing element between the end of the hub and said sleeve, a stuiflng box extending concentric with the shaft, means including a sealing element for drawing the stufling box into sealing relation with the main casing part, and means including an opening in the main casing part communicating with the rearward side of the 1m peller for admitting a non-corrosive inert protective fluid under pressure to said casing to prevent access of the liquid being pumped to said stufllng box.

14. A pump comprising, in combination, a pump casing, an impeller having a hub mounted in said casing, a drive shaft, astufling box through whichsaid shaft extends into driving relation with the impeller, means for supplying lubricant to said stuiiing box, a dam iormed'in the casing adjacent the rotating impeller, a chamber formed in said casing defined by said dam and the adjacent walls of the casing and hub, and means for supplying an inert noncorroslve fluid to said chamber at a pressure such that it forms substantially a fluid barrier adjacent said damfor preventing access of the fluid being pumped to said stufilng box.

15. A pump comprising, in combination, a pump casing, an impeller having a hub mounted in said casing, a drive shaft, a stufling box through which" said shaft extends into driving relation with the impeller, means for supplying 16 lubricant to said stufling box, a dam formed in the casing adjacent the rotating impeller, a chamber formed in said casing defined by said dam and the adjacent walls of the casing and hub, means for supplying an inert non-corrosive fluid to said chamber at a pressure such that it forms substantially a fluid barrier adjacent said dam for preventing access of the fluid being pumped to said stufling box, and means for maintaining the pressure at which the lubricant is supplied to said stufling box at a substantially flxed amount above said fluid pressure.

OTIO W. GREENE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,600,149 Surjanlnofi Sept. 14, 1926 1,677,119 Kinyon July 10, 1928 1,791,849 Stauber Feb. 10, 1931 1,871,747 Schlachter Aug. 16, 1932 1,876,515 Emmet Sept. 6, 1932 2,091,492 Russell Aug. 31, 1937 2,190,670 Mann Feb. 20, 1940 2,283,263 Kates May 19, 1942 2,332,150 Hufl Oct. 19, 1943 2,347,386 Adams Apr. 25, 1944 2,386,898

Karassik Oct. 16, 1945

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