CA1310189C - Method of finish machining the surface of irregularly shaped fluid passages - Google Patents
Method of finish machining the surface of irregularly shaped fluid passagesInfo
- Publication number
- CA1310189C CA1310189C CA000570466A CA570466A CA1310189C CA 1310189 C CA1310189 C CA 1310189C CA 000570466 A CA000570466 A CA 000570466A CA 570466 A CA570466 A CA 570466A CA 1310189 C CA1310189 C CA 1310189C
- Authority
- CA
- Canada
- Prior art keywords
- fixture
- restrictive
- passage
- abrasive
- passageway
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000003754 machining Methods 0.000 title claims abstract description 20
- 239000012530 fluid Substances 0.000 title claims description 54
- 238000000034 method Methods 0.000 title claims description 29
- 230000002093 peripheral effect Effects 0.000 claims description 27
- 239000002245 particle Substances 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 239000002861 polymer material Substances 0.000 claims description 3
- 229920001296 polysiloxane Polymers 0.000 claims description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 3
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 3
- 229910052580 B4C Inorganic materials 0.000 claims description 2
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims description 2
- 239000010431 corundum Substances 0.000 claims description 2
- 229910052593 corundum Inorganic materials 0.000 claims description 2
- 239000010432 diamond Substances 0.000 claims description 2
- 229910003460 diamond Inorganic materials 0.000 claims description 2
- 239000000428 dust Substances 0.000 claims description 2
- 239000002223 garnet Substances 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 2
- 239000011257 shell material Substances 0.000 claims description 2
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 8
- 238000005299 abrasion Methods 0.000 description 14
- 239000000463 material Substances 0.000 description 14
- 238000005498 polishing Methods 0.000 description 10
- 238000010276 construction Methods 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 239000003082 abrasive agent Substances 0.000 description 4
- 230000009969 flowable effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 238000005304 joining Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000005381 potential energy Methods 0.000 description 2
- 241000237074 Centris Species 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical class CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000003822 epoxy resin Chemical class 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000005495 investment casting Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000647 polyepoxide Chemical class 0.000 description 1
- 229920002635 polyurethane Chemical class 0.000 description 1
- 239000004814 polyurethane Chemical class 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
Landscapes
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention is based upon the performance of abrasive flow machining through pump casings and, more particularly, through volute casings whereby the internal surface friction of the casing is substantially reduced to consistently effect a minimal internal friction, operation after operation, and whereby the industry standards for internal friction values for pumps may be established.
The present invention is based upon the performance of abrasive flow machining through pump casings and, more particularly, through volute casings whereby the internal surface friction of the casing is substantially reduced to consistently effect a minimal internal friction, operation after operation, and whereby the industry standards for internal friction values for pumps may be established.
Description
'''" 13101~q A METHOD OF FIN~SH MACHINING THE SURFACE
OF IRREGULARLY SHAPED FLUID PASSAGES
~CRGROUND OF THE INVENTXON
A pump may be defined as a machine or apparatus which imparts energy to a fluid flowing there through. All pumps basically fall into one of two categories or types of pumps: positive displacement pumps and dynamic pumps.
Positive displacement pumps embody one or more chambers and operate by forcing a set volume of fluid from the inlet pressure section of the pump into the discharge portion of the pump, i.e., alternating action of filling and emptying the chambers or chambers with the fluid.
Representative types of positive displacement pumps include reciprocating pumps such as those having piston/plunger type construction, metering construction and diaphragm construction, and rotary pumps such as those having screw rotor type construction and intermeshing gear wheel construction. Reciprocating pumps operate intermittently whereas rotary pumps operate continuously.
Dynamic pumps operate by developing a high fluid velocity and converting the velocity into pressure in a diffusing flow passage. Representative types of dynamic pumps include horizontal or vertical centrifugal pumps, axial pumps and turbine pumps.
Centrifugal pumps comprise a wide class of pumps which in their most essential form consist of two ~asic components. A first component comprises a rotating element, including an impeller mounted on a shaft which is in turn supported by bearings and driven through a flexible or rigid coupling by a driver. A second component comprises a stationary element comprised of a casing, stuffing bo~ and bearings. The casing includes suction and discharge nozzles, supports the bearings, and houses the rotor assembly.
As fluid enter a centrifugal pump, it is forced by atmospheric or other pressure into a set of rotating vanes which constitute an impeller. The impeller imparts tangential acceleration to the fluid and discharges the 1 3 1 0 1 ~9 EH:22B:CAN
~- fluid at a relatively high velocity at its periphery. The velocity the fluid is then converted into pressure energy or pressure head by means of a volute or by a set of stationary diffuser vanes surrounding the impeller periphery. Pumps having volute casings are generally referred to a volute centrifugal pumps have no valves, fluid flow is uniform and free of low-frequency pulsations.
In a closed system such as a centrifugal pump, the principle of conservation of energy states that the total energy input is equal to the total energy output from that system. Bernoulli's equation in its more general form for total mechanical energy balance can be stated as follows:
(Equation 1) P1 + Z1 + V1 + Ep = P2 + Z2 + V2 + FL
where:
P1 is pressure energy at the point of entrance, Zl is potential energy at the point of entrance, V1 is kinetic energy or velocity head at the point of entrance, Ep is pump energy, P2 is pressure energy at the point of exit, Z2 is potential energy at the point of exit, V2 is kinetic energy or velocity head at the point of exit, and FL is friction loss between the point of entrance and point of exit.
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II1 order to determine the power requirement ~f a given pump, Bernoulli's equation can be used in ~he following restated form:
(Equation 2) Ep = (P2 - P1) + (Z2 - Zl) + (V2 - V1) + FL
5It is readily apparent that if friction loss (FL) can be reduced within a given pump, the power requirement for that pump will also be reduced, and considerable savings in operation costs can be realized.
Those skilled in the art have long known that if the friction of a fluid flow through the interior of a centrifugal pump were reduced, the savings in terms of reduced power requirement would be substantial. Since most, if not all centrifugal pump casings are cast~metal, the interior surface of the casings contain variations including surface roughness, pits, nicks, gouges, blow holes, or positive metal. All of these variations will substantially impede fluid flow, i.e., result in substantial friction loss.
Up to now, the only means of remedying these surface variations consisted of manual operations including the utili~ation of files and rotary burr tools, sanding and grinding. These methods, however, are effective largely as corrective measures for gross variations or imperfections.
Single cast pump casings present another problem in that the interior surface of the casing is largely inaccessible to manual operations. Even where the interior surface of the casings is accessible, the difficulty of manual operations in terms of control, uniformity and the degree of physical dexterity required renders the finish on the interior surface of a so-called "finished" casing largely untreated. Further, performance of manual operations on the interior surface of a pump casing is a time consuming task and renders the "finished" article quite expensive.
The present practice by industry is to accept the internal surface variations of casings as unavoidable and compensate for the energy loss due to friction by utilizing - drivers with increased power output capabilities. The result is a higher cost of operation which is attributable .
` 1310189 to higher energy requirements and higher maintenance consists due to increased wear and stress of the moving parts of the pump.
The foregoing serves to illustrate the state of the art and the problem addressed and solved by the present invention.
It is an object of an aspect of the present invention to provide a method of working the interior surface of pump casings to reduce internal fluid flow friction of dynamic pumps.
It is an object of an aspect of the invention to provide such a method to reduce the internal fluid flow friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide a method of providing and ensuring a consistent level of minimal internal fluid flow friction of dynamic pumps.
An object of an aspect of the invention is to provide a method of providing and ensuring a uniform level of minimal internal fluid flow friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide a method of providing industry with a standard of minimal internal fluid flow friction of dynamic pumps.
An object of an aspect of the invention is to provide a method of providing industry with a standard of minimal internal friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide parts and components which have been worked to effect minimal internal fluid flow friction in dynamic pumps.
An object of an aspect of the invention is to provide parts and components which have been worked to '` ' '' ' ~ ~; ' ~ ' ' `
'"' ' 13lol89 effect minimal internal fluid flow friction in centrifugal volute pumps.
The present invention is based upon the performance of abrasive flow machining through pump casings and more particularly, through volute casings whereby the internal surface friction of the casing is substantially reduced to consistently effect a minimal internal friction, operation after operation, and whereby the industry standards for internal friction values for pumps may be established.
An aspect of this invention is as follows:
A method of abrasive flow machining the surface of irregularly shaped fluid passages comprising:
placing a restrictive fixture within the fluid passageway of the irregularly shaped fluid passage to equalize the cross-sectional area throughout the length of the fluid passageway;
extruding a visco-elastic abrasive medium through the fluid passage;
removing said restrictive fixture; and removing said visco~elastic abrasive medium from the irregularly shaped fluid passage.
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~RIEF DESCRIPTION O~ THE DE~WI~GS
Fig. l is a side, cross-sectiona:L view of a typical centri~ugal pump showing the impeller, casing and volute.
Fig. 2 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig. 3 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig. 4 is a cross-sectional view of a centrifugal pump with the impeller removed and with the rostrictive fixture in place.
Fig. 5 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig 6 is a cross-section view of a centrifugal pump with the impeller removed showing an alternate embodiment of the restrictive fixture.
Fig. 7 is a sectional view taken generally along line 7-7 of Fig. 6 showing the mounting plate, inlet passageway and peripheral passageway.
DETAI~ED DESC~IPTION O~ INVENTION
Abrasive flow machining is a process for working metals and related materials. It is particularly useful for machining and honing the edges and surfaces of such materials. Some of the operations realizable using this process include deburring, radiusing, resizing, polishing and other related material finishing operations.
Unlike any other machining process~ abrasive flow machining employs non-Newtonian semi-solid polymer compositions as the abrasive carrying medium. The physical properties of this medium include viscoelasticity and rheological dilatancy. Accordingly, the viscosity of the medium increases with increased shear stress, and when the shear is removed, the viscous properties return wholly or partially to their original state. It is therefore apparent that abrasive flow machining as employed in the present method does not include flow of abrasives suspended .
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or slurrie(~ Ln fluid media such as cutting fluids, honing fluids, gas streams and the like, but rather is limited to non-Newtonian semi-solid polymer compositions which form stable, non-separating intermixtures with solid particulate 5 abrasives whose flow is characterized by rheological dilatancy.
The rheopetic medium employed in the present method enables substantially non-abrasive flow at low shear conditions by plastic deformation, and substantially high abrasive flow by quasi-solid plug flow properties when shear conditions are high. Accordingly, abrasion is effected only on those surfaces or areas where high shear conditions exist. Other surfaces or areas having low shear conditions are relatively unaffected.
The medium employed in the present method is a semi-solid, visco-elastic, rheopectic polymer material which has the consistency of putty. It is important -to note that the medium used must have sufficient body at high pressure and low velocity to provide backing for the abrasive particles so that the abrasive particles are pressed against the surface to be treated with sufficient force to obtain the desired result. One suitable medium is silicone putty, i.e., borosiloxane, of a grade indicated by the General Electric Company as SS-91. This material has a bounce or rebound of 25 to 50 percent when a twelve gram ball of the putty at 21.1 to 25.6 degrees Centigrade is dropped from a height of 254 cm onto a smooth surfaced soapstone block.
This material has a resilience of 10 to 20 percent when measured with a Bashore Resiliometer o~ the Precision Scientific Company of Chicago, at room temperature and with a special 14.18 g drop weight. This material has a penetration of 1.5 to 10 mm in five seconds when measured with a Precision Universal Penetrometer with a 0.635 cm diameter, 30.5 cm, ~7.5 gram test rod with no external loading. These tests were made at least twenty-four hours after the batch of putty was dropped or first formed in order to ensure reliable testing results.
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Silicone putty, by strict definition, is a solid. It exhibits, however, many characteristics of a fluid. It is compressible and, therefore, expandable. Under pressure, it becomes less flowable and behaves more like a solid. It conforms exactly to whatever confines it, and thus, ensures abrasion of all surface areas of the passageway where ever high shear conditions exist, i.e. passageway areas where flow is restricted and/or peripheral passageway areas where changes in the direction of flow occur.
Additives can be added to the putty to render it more plastic and flowable or more stiff and tough and less flowable, depending on the desired flowability. For example a small amount of plasticizer or softener can be added to the putty to render it slightly more plastic and flowable than when it was originally dropped or formed. If stiffening or more toughness and, therefore, less flowability is desired, a hardening agent such as tetrafluoreothylene, more commonly known as Teflon, in the form of small beads, powder or levitated talc can be added to the putty.
The abrasive used with the medium will, of course, depend, upon the result desired. A suitable abrasive for use in working on steel is silicon carbide. A widely used abrasive is aluminum oxid~. Other suitable abrasives include boron carbide, titanium carbide, diamond dust, rouge, corundum, garnet, alundum, glass and, in certain applications, softer materials such as fiber or shell material. Normally, the content of abrasive material per part of putty material will be from about two parts to about fifteen parts by weight. typically, abrasive particle size range from `1000 mesh to 8 mesh. Larger size abrasive particles effect deeper cuts per grain.
Accordingly, if faster cutting time with possibly a rougher final surface finish is desired, larger size abrasive particles would be suitable. Depending on the result desired, however, a mixture of abrasive particle sizes can be used with the putty.
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In the present lnvention, it is generally desirable to employ coarse abrasive particles in the rage between 10 mesh and 30 mesh. Using an abrasive media containing abrasive particles of such size will effect both machining and polishing action with a smooth surface finish as the result. It is also possible to employ abrasive ~low machining or polishing in multiple steps - the initial stage being conducted with an abrasive medium containing larger sized abrasive particles and subsequent abrasive flow operations being conducted with abrasive media containing finer abrasive particles. Whether or not a single, double or multiple steps are used in performin~
abrasive flow machining or polishing will depend upon the desired result as well as considerations of efficiency.
For example, a two-step operation wherein the workpiece is initially abrasive flow machined or polished with an abrasive medium containing larger sized abrasive particles and then subsequently abrasive flow polished with an abrasive medium containing finer abrasive particles may be desirable where the result desired is a fine, reflective finish and the target surface of the workpiece contains multiple burrs and large imperfections.
It is to be noted that the intermixture of putty and abrasive particles should yenerally be of a uniform consistency in order to obtain maximum abrasion efficiency.
The cutting efficiency of the intermixture of putty and abrasive particles is, however, surprisingly tolerant to material content changes. For example, the material removed by the abrasive media becomes part of the abrasive media, and the abrasive media as a whole can tolerate as much as 10 percent or higher by volume of such removed material before cutting performance is affected.
In order to apply abrasive flow machining to a workpiece, the typical practice is to hold the workpiece between a pair of hydraulically closed cylinders so as to confine, direct and restrict the media flow so that the areas or surfaces of the workpiece where abrasion is desired form the greatest restriction in the media flow , ' ', . :
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path. By extruding the abrasive media back and forth across the target surface of the workpiece from one ~edia cylinder to the other, abrasive action is produced where flow is restricted passing through or across the workpiece.
Other means o~ confining, directing and restricting the media flow apparatus or multiple cylinder apparatus may also be used such, being within the ordinary skill of the art.
In the case of a substan-tially cylindrical pipe, the operation of polishing the wall surface the pipe passageway is relatively easy since the cross-sectional area of the pipe passageway is uniform. This uniformity in cross-sectional area ensures uniform shear rate on the abrasive media along and throughout the length of the pipe passageway. Accordingly, abrasive action on the wall surface of the pipe passageway is uniform and can result in a highly polished wall surface. In the case of abrasive flow machining or polishing the wall surfaces of passages having varying cross-sectional areas, however, the process becomes more complicated. As previously noted, the wall surface at the point of greatest restriction within a passageway will receive the greatest amount of abrasion.
In the case of passages with varying corss-sectional areas, abrasion is effected predominantly where the cross-sectional area is the least in size.
In the case of volute casings, the fluid passageway isdesigned with a consistently changing passage size to increase or decrease the pressure buildup of the fluid flowing through it during operation, i.e., the cross-sectional area of the fluid passageway increases from theinlet opening towards the outlet opening. To properly abrasive flow machine or polish such a passageway, the cross-sectional area must be held constant throughout the length of the passageway, i.e., the restrictiveness of the passageway must be held at a constant~ If the cross-sectional area of the passageway is not held at a constant throughout the length of the passageway, then those areas with the most restrictiveness (least cross-sectional area) 1 3 1 0 1 ~9 EH:22B:CAN
would experience more abrasion than the less restrictive areas (larger cross-sectional area).
In the method of this invention, a special restrictive fixture i9 place with the passageway of the volute casing.
This special restrictive fixture is designed to effect a constant cross-sectional area along the entire length of the passageway, i.e., the shape of the restrictive fixture corresponds obversely to the shape of the passageway so as to equalize the cross-sectional area along the entire length of the passageway. The configuration of the restrictive fixture resemoles a negative image of the volute fluid passageway at reduced scale. As such, when the restrictive fixture is placed in position inside the volute casing, a gap is established between the restrictive figure and the wall of the fluid passageway of the volute casing. ~ccordingly, when the restrictive fixture is placed with the passageway of the volute casing, it mates with the passageway in such a way that the peripheral wall surface of the restrictive fixture and the peripheral wall surface of the fluid passageway define the boundaries of the peripheral passageway through which extrusion media travels.
The inlet for the extrusion media can be located near the center of the casing, i.e., more or less centered with the shaft, such being a convenient site for the location of an inlet. The restrictive fixture will accordingly be adapted to have an inlet opening near its center from which extends an inlet passage joining the inlet opening with the peripheral passageway.
The cross-sectional area of the inlet opening and inlet passageway is a function of the cross-sectional area of the peripheral passageway. In all instances, however, the cross-sectional area of the inlet opening and inlet passageway must be greater than the cross-sectional area of the peripheral passageway.
The restrictive fixture as used in the present method is formed by casting using either urethane, polyurethane, epoxy resin compounds, and other like materials. These l/
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~ materials are less susceptible to abrasion than the iron-cast casting. In all instances, the restrictive fixture should be made from a composition which is less susceptible to abrasion than the material of the workpiece. Otherwise, the utility lifetime of the restrictive fixture will be decreased due to increased rate of deformation.
The restrictive fixture as used in the present invention is held in place by mounting the restrictive fixture onto a mounting plate.
The mounting plate used may be the face plate of the centrifugal pump, but other suitable means such as sealer plates may be used, such being within the ordinary skill of the art. After formation and removal from the mold the restrictive fixture is mounted on a mounting plate, after which the mounting plate-restrictive fixture assembly is mounted on the volute casing. Alternatively, the volute casing can be mounted on the mounting plate-restrictive fixture assembly. With the cross-sectional area of the fluid passageway being now held at a constant throughout the length of the volute passageway, the surface of the fluid passageway of the volute casing is ready for abrasive flow machining or polishing.
As previously noted, in order to apply abrasive flow machining or polishing to a workpiece, it is a typical practice to hold the workpiece between a pair of hydraulically closed cylinders so as to confine, direct and restrict the media flow to the area or surface of the workpiece where abrasion is desired. By extruding the media back and forth between the two directly opposed media cylinders, across the target area or surface of the workpiece, abrasive action is produced where media flow is restricted passing through or across the target area or surface area of the workpiece.
Since the cross-sectional area of the fluid flow passageway of a volute casing fitted with a restrictive fixture is substantially equalized throughout the length of the passageway, abrasive flow machining or polishing can be accomplished in much the same way as with a cylindrical /~
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pipe. One opening of the volute casing is fitted and sealed to one hydraulically closed cylinder, and the other opening of the volute casing is fitted and sealed to another hydraulically closed cylinder. Abrasive media consisting of the intermixture of putty and abrasive particles is then extruded back and forth from one media cylinder to another through the peripheral passageway of the casing. Since the cross-sectional area of the peripheral passageway is constant throughout the length of the passageway, restrictive forces or shear stress on the abrasive mixture remains constant and effects uniform abrasive action on the surface of the peripheral passageway of the casing along the entire length of the passageway.
It is to be noted that with the use of abrasive flow machining or polishing, the peripheral surface areas of the passageway where abrupt changes in flow direction occur experience more abrasion. In the case where the inlet for the extrusion media is located near the center of the casing, the restrictive fixture would, as previously noted, be adapted to have an inlet opening near its center from which extends the inlet passage joining the inlet opening with the peripheral passageway. If the inlet passage is adapted in a straight line from the central inlet opening to the peripheral passageway, thereby rendering the inlet passageway perpendicular to the peripheral passageway then the surface area of the peripheral passageway where the inlet passage intersects with the peripheral passageway would experience greater abrasion, said intersection being where an abrupt change in flow direction occurs, e.g., almost 90 change in flow direction.
The restrictive fixture of the present invention avoids this problem of abrupt change in flow direction by confining all such flow changes to areas within the restrictive fixture. The configuration of the inlet passage within the restrictive fixture is such that the media flow where the inlet passage intersects with the peripheral passageway is rendered tangential to the peripheral passageway. Accordingly, abrasion on the /~
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surface area Gf the perlpheral passageway where the inlet passage intersects with the peripheral passageway is non-excessive and uniform with abrasion on the surface area of the rest of the peripheral passageway.
Depending on the result desired, the extrusion pressure and operation time may be varied. For example, the extrusion pressure can be varied anywhere from 0.34 bar to 124.11 bar. Actual extrudlng operation time can vary from seconds to hours. Further, the flow rate of the extruding media can also be varied to meet specific requirements.
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A centrifugal volute pump casing shown in Fig. 1 was obtained by investment casting. The casing was fitted with a mold-cast restrictive fixture having a spiral configuration conforming to the interior of the volute casing by attachment of the restrictive fixture onto a mounting plate and fitting the restrictive fixture and mounting plate assembly onto the casing. The restrictive fixture was cast in such size and shape so that when it was put in place inside the volute casing, the cross-sectional area throughout the length of the volute fluid passageway remained constant. The casing was then mounted on an abrasive flow machine. The machine was loaded with an abrasive medium comprising borosiloxane loaded with 2 parts by weight of silicon carbide in a 50-50 mixture of 16 mesh and 24 mesh per part of siloxane. The casing was then abrasive flow machined/polished for 5-minutes under a pressure of 41.37 bar. The casing was then removed from the machinery, the restrictive fixture removed, and then cleaned. A smooth surface finish was thus obtained on the polished area of the volute fluid passageway. The casing was assembled with the impeller and face plate and fitted for testing. The results showed a power requirement decrease from 15 horsepower to 14 horsepower.
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OF IRREGULARLY SHAPED FLUID PASSAGES
~CRGROUND OF THE INVENTXON
A pump may be defined as a machine or apparatus which imparts energy to a fluid flowing there through. All pumps basically fall into one of two categories or types of pumps: positive displacement pumps and dynamic pumps.
Positive displacement pumps embody one or more chambers and operate by forcing a set volume of fluid from the inlet pressure section of the pump into the discharge portion of the pump, i.e., alternating action of filling and emptying the chambers or chambers with the fluid.
Representative types of positive displacement pumps include reciprocating pumps such as those having piston/plunger type construction, metering construction and diaphragm construction, and rotary pumps such as those having screw rotor type construction and intermeshing gear wheel construction. Reciprocating pumps operate intermittently whereas rotary pumps operate continuously.
Dynamic pumps operate by developing a high fluid velocity and converting the velocity into pressure in a diffusing flow passage. Representative types of dynamic pumps include horizontal or vertical centrifugal pumps, axial pumps and turbine pumps.
Centrifugal pumps comprise a wide class of pumps which in their most essential form consist of two ~asic components. A first component comprises a rotating element, including an impeller mounted on a shaft which is in turn supported by bearings and driven through a flexible or rigid coupling by a driver. A second component comprises a stationary element comprised of a casing, stuffing bo~ and bearings. The casing includes suction and discharge nozzles, supports the bearings, and houses the rotor assembly.
As fluid enter a centrifugal pump, it is forced by atmospheric or other pressure into a set of rotating vanes which constitute an impeller. The impeller imparts tangential acceleration to the fluid and discharges the 1 3 1 0 1 ~9 EH:22B:CAN
~- fluid at a relatively high velocity at its periphery. The velocity the fluid is then converted into pressure energy or pressure head by means of a volute or by a set of stationary diffuser vanes surrounding the impeller periphery. Pumps having volute casings are generally referred to a volute centrifugal pumps have no valves, fluid flow is uniform and free of low-frequency pulsations.
In a closed system such as a centrifugal pump, the principle of conservation of energy states that the total energy input is equal to the total energy output from that system. Bernoulli's equation in its more general form for total mechanical energy balance can be stated as follows:
(Equation 1) P1 + Z1 + V1 + Ep = P2 + Z2 + V2 + FL
where:
P1 is pressure energy at the point of entrance, Zl is potential energy at the point of entrance, V1 is kinetic energy or velocity head at the point of entrance, Ep is pump energy, P2 is pressure energy at the point of exit, Z2 is potential energy at the point of exit, V2 is kinetic energy or velocity head at the point of exit, and FL is friction loss between the point of entrance and point of exit.
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, 1 3 1 0 ~ ~9 EH:22B:CAN
II1 order to determine the power requirement ~f a given pump, Bernoulli's equation can be used in ~he following restated form:
(Equation 2) Ep = (P2 - P1) + (Z2 - Zl) + (V2 - V1) + FL
5It is readily apparent that if friction loss (FL) can be reduced within a given pump, the power requirement for that pump will also be reduced, and considerable savings in operation costs can be realized.
Those skilled in the art have long known that if the friction of a fluid flow through the interior of a centrifugal pump were reduced, the savings in terms of reduced power requirement would be substantial. Since most, if not all centrifugal pump casings are cast~metal, the interior surface of the casings contain variations including surface roughness, pits, nicks, gouges, blow holes, or positive metal. All of these variations will substantially impede fluid flow, i.e., result in substantial friction loss.
Up to now, the only means of remedying these surface variations consisted of manual operations including the utili~ation of files and rotary burr tools, sanding and grinding. These methods, however, are effective largely as corrective measures for gross variations or imperfections.
Single cast pump casings present another problem in that the interior surface of the casing is largely inaccessible to manual operations. Even where the interior surface of the casings is accessible, the difficulty of manual operations in terms of control, uniformity and the degree of physical dexterity required renders the finish on the interior surface of a so-called "finished" casing largely untreated. Further, performance of manual operations on the interior surface of a pump casing is a time consuming task and renders the "finished" article quite expensive.
The present practice by industry is to accept the internal surface variations of casings as unavoidable and compensate for the energy loss due to friction by utilizing - drivers with increased power output capabilities. The result is a higher cost of operation which is attributable .
` 1310189 to higher energy requirements and higher maintenance consists due to increased wear and stress of the moving parts of the pump.
The foregoing serves to illustrate the state of the art and the problem addressed and solved by the present invention.
It is an object of an aspect of the present invention to provide a method of working the interior surface of pump casings to reduce internal fluid flow friction of dynamic pumps.
It is an object of an aspect of the invention to provide such a method to reduce the internal fluid flow friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide a method of providing and ensuring a consistent level of minimal internal fluid flow friction of dynamic pumps.
An object of an aspect of the invention is to provide a method of providing and ensuring a uniform level of minimal internal fluid flow friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide a method of providing industry with a standard of minimal internal fluid flow friction of dynamic pumps.
An object of an aspect of the invention is to provide a method of providing industry with a standard of minimal internal friction of centrifugal volute pumps.
An object of an aspect of the invention is to provide parts and components which have been worked to effect minimal internal fluid flow friction in dynamic pumps.
An object of an aspect of the invention is to provide parts and components which have been worked to '` ' '' ' ~ ~; ' ~ ' ' `
'"' ' 13lol89 effect minimal internal fluid flow friction in centrifugal volute pumps.
The present invention is based upon the performance of abrasive flow machining through pump casings and more particularly, through volute casings whereby the internal surface friction of the casing is substantially reduced to consistently effect a minimal internal friction, operation after operation, and whereby the industry standards for internal friction values for pumps may be established.
An aspect of this invention is as follows:
A method of abrasive flow machining the surface of irregularly shaped fluid passages comprising:
placing a restrictive fixture within the fluid passageway of the irregularly shaped fluid passage to equalize the cross-sectional area throughout the length of the fluid passageway;
extruding a visco-elastic abrasive medium through the fluid passage;
removing said restrictive fixture; and removing said visco~elastic abrasive medium from the irregularly shaped fluid passage.
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~RIEF DESCRIPTION O~ THE DE~WI~GS
Fig. l is a side, cross-sectiona:L view of a typical centri~ugal pump showing the impeller, casing and volute.
Fig. 2 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig. 3 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig. 4 is a cross-sectional view of a centrifugal pump with the impeller removed and with the rostrictive fixture in place.
Fig. 5 is a cross-sectional view of a centrifugal pump with the impeller removed and with the restrictive fixture in place.
Fig 6 is a cross-section view of a centrifugal pump with the impeller removed showing an alternate embodiment of the restrictive fixture.
Fig. 7 is a sectional view taken generally along line 7-7 of Fig. 6 showing the mounting plate, inlet passageway and peripheral passageway.
DETAI~ED DESC~IPTION O~ INVENTION
Abrasive flow machining is a process for working metals and related materials. It is particularly useful for machining and honing the edges and surfaces of such materials. Some of the operations realizable using this process include deburring, radiusing, resizing, polishing and other related material finishing operations.
Unlike any other machining process~ abrasive flow machining employs non-Newtonian semi-solid polymer compositions as the abrasive carrying medium. The physical properties of this medium include viscoelasticity and rheological dilatancy. Accordingly, the viscosity of the medium increases with increased shear stress, and when the shear is removed, the viscous properties return wholly or partially to their original state. It is therefore apparent that abrasive flow machining as employed in the present method does not include flow of abrasives suspended .
1 3 1 0 ~ 89 EH:22B:CAN
or slurrie(~ Ln fluid media such as cutting fluids, honing fluids, gas streams and the like, but rather is limited to non-Newtonian semi-solid polymer compositions which form stable, non-separating intermixtures with solid particulate 5 abrasives whose flow is characterized by rheological dilatancy.
The rheopetic medium employed in the present method enables substantially non-abrasive flow at low shear conditions by plastic deformation, and substantially high abrasive flow by quasi-solid plug flow properties when shear conditions are high. Accordingly, abrasion is effected only on those surfaces or areas where high shear conditions exist. Other surfaces or areas having low shear conditions are relatively unaffected.
The medium employed in the present method is a semi-solid, visco-elastic, rheopectic polymer material which has the consistency of putty. It is important -to note that the medium used must have sufficient body at high pressure and low velocity to provide backing for the abrasive particles so that the abrasive particles are pressed against the surface to be treated with sufficient force to obtain the desired result. One suitable medium is silicone putty, i.e., borosiloxane, of a grade indicated by the General Electric Company as SS-91. This material has a bounce or rebound of 25 to 50 percent when a twelve gram ball of the putty at 21.1 to 25.6 degrees Centigrade is dropped from a height of 254 cm onto a smooth surfaced soapstone block.
This material has a resilience of 10 to 20 percent when measured with a Bashore Resiliometer o~ the Precision Scientific Company of Chicago, at room temperature and with a special 14.18 g drop weight. This material has a penetration of 1.5 to 10 mm in five seconds when measured with a Precision Universal Penetrometer with a 0.635 cm diameter, 30.5 cm, ~7.5 gram test rod with no external loading. These tests were made at least twenty-four hours after the batch of putty was dropped or first formed in order to ensure reliable testing results.
~ 3 1 0 1 89 EH:22B:CAN
Silicone putty, by strict definition, is a solid. It exhibits, however, many characteristics of a fluid. It is compressible and, therefore, expandable. Under pressure, it becomes less flowable and behaves more like a solid. It conforms exactly to whatever confines it, and thus, ensures abrasion of all surface areas of the passageway where ever high shear conditions exist, i.e. passageway areas where flow is restricted and/or peripheral passageway areas where changes in the direction of flow occur.
Additives can be added to the putty to render it more plastic and flowable or more stiff and tough and less flowable, depending on the desired flowability. For example a small amount of plasticizer or softener can be added to the putty to render it slightly more plastic and flowable than when it was originally dropped or formed. If stiffening or more toughness and, therefore, less flowability is desired, a hardening agent such as tetrafluoreothylene, more commonly known as Teflon, in the form of small beads, powder or levitated talc can be added to the putty.
The abrasive used with the medium will, of course, depend, upon the result desired. A suitable abrasive for use in working on steel is silicon carbide. A widely used abrasive is aluminum oxid~. Other suitable abrasives include boron carbide, titanium carbide, diamond dust, rouge, corundum, garnet, alundum, glass and, in certain applications, softer materials such as fiber or shell material. Normally, the content of abrasive material per part of putty material will be from about two parts to about fifteen parts by weight. typically, abrasive particle size range from `1000 mesh to 8 mesh. Larger size abrasive particles effect deeper cuts per grain.
Accordingly, if faster cutting time with possibly a rougher final surface finish is desired, larger size abrasive particles would be suitable. Depending on the result desired, however, a mixture of abrasive particle sizes can be used with the putty.
1 3 1 0 1 89 EH:22B:C~N
In the present lnvention, it is generally desirable to employ coarse abrasive particles in the rage between 10 mesh and 30 mesh. Using an abrasive media containing abrasive particles of such size will effect both machining and polishing action with a smooth surface finish as the result. It is also possible to employ abrasive ~low machining or polishing in multiple steps - the initial stage being conducted with an abrasive medium containing larger sized abrasive particles and subsequent abrasive flow operations being conducted with abrasive media containing finer abrasive particles. Whether or not a single, double or multiple steps are used in performin~
abrasive flow machining or polishing will depend upon the desired result as well as considerations of efficiency.
For example, a two-step operation wherein the workpiece is initially abrasive flow machined or polished with an abrasive medium containing larger sized abrasive particles and then subsequently abrasive flow polished with an abrasive medium containing finer abrasive particles may be desirable where the result desired is a fine, reflective finish and the target surface of the workpiece contains multiple burrs and large imperfections.
It is to be noted that the intermixture of putty and abrasive particles should yenerally be of a uniform consistency in order to obtain maximum abrasion efficiency.
The cutting efficiency of the intermixture of putty and abrasive particles is, however, surprisingly tolerant to material content changes. For example, the material removed by the abrasive media becomes part of the abrasive media, and the abrasive media as a whole can tolerate as much as 10 percent or higher by volume of such removed material before cutting performance is affected.
In order to apply abrasive flow machining to a workpiece, the typical practice is to hold the workpiece between a pair of hydraulically closed cylinders so as to confine, direct and restrict the media flow so that the areas or surfaces of the workpiece where abrasion is desired form the greatest restriction in the media flow , ' ', . :
, I 3 1 0 1 ~ ~ E~1 22B CAN
path. By extruding the abrasive media back and forth across the target surface of the workpiece from one ~edia cylinder to the other, abrasive action is produced where flow is restricted passing through or across the workpiece.
Other means o~ confining, directing and restricting the media flow apparatus or multiple cylinder apparatus may also be used such, being within the ordinary skill of the art.
In the case of a substan-tially cylindrical pipe, the operation of polishing the wall surface the pipe passageway is relatively easy since the cross-sectional area of the pipe passageway is uniform. This uniformity in cross-sectional area ensures uniform shear rate on the abrasive media along and throughout the length of the pipe passageway. Accordingly, abrasive action on the wall surface of the pipe passageway is uniform and can result in a highly polished wall surface. In the case of abrasive flow machining or polishing the wall surfaces of passages having varying cross-sectional areas, however, the process becomes more complicated. As previously noted, the wall surface at the point of greatest restriction within a passageway will receive the greatest amount of abrasion.
In the case of passages with varying corss-sectional areas, abrasion is effected predominantly where the cross-sectional area is the least in size.
In the case of volute casings, the fluid passageway isdesigned with a consistently changing passage size to increase or decrease the pressure buildup of the fluid flowing through it during operation, i.e., the cross-sectional area of the fluid passageway increases from theinlet opening towards the outlet opening. To properly abrasive flow machine or polish such a passageway, the cross-sectional area must be held constant throughout the length of the passageway, i.e., the restrictiveness of the passageway must be held at a constant~ If the cross-sectional area of the passageway is not held at a constant throughout the length of the passageway, then those areas with the most restrictiveness (least cross-sectional area) 1 3 1 0 1 ~9 EH:22B:CAN
would experience more abrasion than the less restrictive areas (larger cross-sectional area).
In the method of this invention, a special restrictive fixture i9 place with the passageway of the volute casing.
This special restrictive fixture is designed to effect a constant cross-sectional area along the entire length of the passageway, i.e., the shape of the restrictive fixture corresponds obversely to the shape of the passageway so as to equalize the cross-sectional area along the entire length of the passageway. The configuration of the restrictive fixture resemoles a negative image of the volute fluid passageway at reduced scale. As such, when the restrictive fixture is placed in position inside the volute casing, a gap is established between the restrictive figure and the wall of the fluid passageway of the volute casing. ~ccordingly, when the restrictive fixture is placed with the passageway of the volute casing, it mates with the passageway in such a way that the peripheral wall surface of the restrictive fixture and the peripheral wall surface of the fluid passageway define the boundaries of the peripheral passageway through which extrusion media travels.
The inlet for the extrusion media can be located near the center of the casing, i.e., more or less centered with the shaft, such being a convenient site for the location of an inlet. The restrictive fixture will accordingly be adapted to have an inlet opening near its center from which extends an inlet passage joining the inlet opening with the peripheral passageway.
The cross-sectional area of the inlet opening and inlet passageway is a function of the cross-sectional area of the peripheral passageway. In all instances, however, the cross-sectional area of the inlet opening and inlet passageway must be greater than the cross-sectional area of the peripheral passageway.
The restrictive fixture as used in the present method is formed by casting using either urethane, polyurethane, epoxy resin compounds, and other like materials. These l/
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.
1 3 I n 1 ~9 EH:22B:CAN
~ materials are less susceptible to abrasion than the iron-cast casting. In all instances, the restrictive fixture should be made from a composition which is less susceptible to abrasion than the material of the workpiece. Otherwise, the utility lifetime of the restrictive fixture will be decreased due to increased rate of deformation.
The restrictive fixture as used in the present invention is held in place by mounting the restrictive fixture onto a mounting plate.
The mounting plate used may be the face plate of the centrifugal pump, but other suitable means such as sealer plates may be used, such being within the ordinary skill of the art. After formation and removal from the mold the restrictive fixture is mounted on a mounting plate, after which the mounting plate-restrictive fixture assembly is mounted on the volute casing. Alternatively, the volute casing can be mounted on the mounting plate-restrictive fixture assembly. With the cross-sectional area of the fluid passageway being now held at a constant throughout the length of the volute passageway, the surface of the fluid passageway of the volute casing is ready for abrasive flow machining or polishing.
As previously noted, in order to apply abrasive flow machining or polishing to a workpiece, it is a typical practice to hold the workpiece between a pair of hydraulically closed cylinders so as to confine, direct and restrict the media flow to the area or surface of the workpiece where abrasion is desired. By extruding the media back and forth between the two directly opposed media cylinders, across the target area or surface of the workpiece, abrasive action is produced where media flow is restricted passing through or across the target area or surface area of the workpiece.
Since the cross-sectional area of the fluid flow passageway of a volute casing fitted with a restrictive fixture is substantially equalized throughout the length of the passageway, abrasive flow machining or polishing can be accomplished in much the same way as with a cylindrical /~
- , 1 3 1 n 1 89 E;H:22B:CAN
pipe. One opening of the volute casing is fitted and sealed to one hydraulically closed cylinder, and the other opening of the volute casing is fitted and sealed to another hydraulically closed cylinder. Abrasive media consisting of the intermixture of putty and abrasive particles is then extruded back and forth from one media cylinder to another through the peripheral passageway of the casing. Since the cross-sectional area of the peripheral passageway is constant throughout the length of the passageway, restrictive forces or shear stress on the abrasive mixture remains constant and effects uniform abrasive action on the surface of the peripheral passageway of the casing along the entire length of the passageway.
It is to be noted that with the use of abrasive flow machining or polishing, the peripheral surface areas of the passageway where abrupt changes in flow direction occur experience more abrasion. In the case where the inlet for the extrusion media is located near the center of the casing, the restrictive fixture would, as previously noted, be adapted to have an inlet opening near its center from which extends the inlet passage joining the inlet opening with the peripheral passageway. If the inlet passage is adapted in a straight line from the central inlet opening to the peripheral passageway, thereby rendering the inlet passageway perpendicular to the peripheral passageway then the surface area of the peripheral passageway where the inlet passage intersects with the peripheral passageway would experience greater abrasion, said intersection being where an abrupt change in flow direction occurs, e.g., almost 90 change in flow direction.
The restrictive fixture of the present invention avoids this problem of abrupt change in flow direction by confining all such flow changes to areas within the restrictive fixture. The configuration of the inlet passage within the restrictive fixture is such that the media flow where the inlet passage intersects with the peripheral passageway is rendered tangential to the peripheral passageway. Accordingly, abrasion on the /~
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!
1 3 1 0 1 ~ ~H:22B:c~N
surface area Gf the perlpheral passageway where the inlet passage intersects with the peripheral passageway is non-excessive and uniform with abrasion on the surface area of the rest of the peripheral passageway.
Depending on the result desired, the extrusion pressure and operation time may be varied. For example, the extrusion pressure can be varied anywhere from 0.34 bar to 124.11 bar. Actual extrudlng operation time can vary from seconds to hours. Further, the flow rate of the extruding media can also be varied to meet specific requirements.
/~
1 3 1 0 1 ~9 EH 22B:CAN
A centrifugal volute pump casing shown in Fig. 1 was obtained by investment casting. The casing was fitted with a mold-cast restrictive fixture having a spiral configuration conforming to the interior of the volute casing by attachment of the restrictive fixture onto a mounting plate and fitting the restrictive fixture and mounting plate assembly onto the casing. The restrictive fixture was cast in such size and shape so that when it was put in place inside the volute casing, the cross-sectional area throughout the length of the volute fluid passageway remained constant. The casing was then mounted on an abrasive flow machine. The machine was loaded with an abrasive medium comprising borosiloxane loaded with 2 parts by weight of silicon carbide in a 50-50 mixture of 16 mesh and 24 mesh per part of siloxane. The casing was then abrasive flow machined/polished for 5-minutes under a pressure of 41.37 bar. The casing was then removed from the machinery, the restrictive fixture removed, and then cleaned. A smooth surface finish was thus obtained on the polished area of the volute fluid passageway. The casing was assembled with the impeller and face plate and fitted for testing. The results showed a power requirement decrease from 15 horsepower to 14 horsepower.
.
Claims (11)
1. A method of abrasive flow machining the surface of irregularly shaped fluid passages comprising:
placing a restrictive fixture within the fluid passageway of the irregularly shaped fluid passage to equalize the cross-sectional area throughout the length of the fluid passageway;
extruding a visco-elastic abrasive medium through the fluid passage;
removing said restrictive fixture; and removing said visco-elastic abrasive medium from the irregularly shaped fluid passage.
placing a restrictive fixture within the fluid passageway of the irregularly shaped fluid passage to equalize the cross-sectional area throughout the length of the fluid passageway;
extruding a visco-elastic abrasive medium through the fluid passage;
removing said restrictive fixture; and removing said visco-elastic abrasive medium from the irregularly shaped fluid passage.
2. The method of claim 1 wherein the visco-elastic abrasive medium comprises an intermixture of abrasive particles and a semi-solid, visco-elastic, rheologically dilatant polymer material having the consistency of putty.
3. The method of claim 1 wherein the restrictive fixture comprises a mold-cast, abrasive-resistant fixture, said fixture having a configuration which is obversely related to and reduced in scale relative to the irregularly shaped fluid passage.
4. The method of claim 1 wherein the irregularly shaped fluid passage is a volute passage of a centrifugal pump.
5. The method of claim 4 wherein the restrictive fixture comprises a mold-cast, abrasive-resistant fixture having a spiral configuration.
6. The method of claim 2 wherein the semi-solid, visco-elastic, rheologically dilatant polymer material is a silicone putty.
7. The method of claim 2 wherein the abrasive particle is selected from a group consisting of silicon carbide, boron carbide, aluminum oxide, titanium carbide, diamond dust, rouge, corundum, garnet, alundum, glass, shell material and mixtures thereof.
8. The method of claim 2 wherein the size of the abrasive particle is less than 8 mesh.
9. The method of claim 1 wherein the restrictive fixture comprises a passage for media flow, characterized in that the configuration of said passage within said restrictive fixture renders the direction of media flow tangential with the surface of said peripheral fluid passageway in the area where said passage intersects with the peripheral fluid passageway.
10. The method of claim 3 wherein the restrictive fixture comprises a passage for media flow, characterized in that the configuration of said passage within said restrictive fixture renders the direction of media flow tangential with the surface of said peripheral fluid passageway in the area where said passage intersects with the peripheral fluid passageway.
11. The method of claim 5 wherein the restrictive fixture comprises a passage for media flow, characterized in that the configuration of said passage within said restrictive fixture renders the direction of media flow tangential with the surface of said peripheral fluid passageway in the area where said passage intersects with the peripheral fluid passageway.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000570466A CA1310189C (en) | 1988-06-27 | 1988-06-27 | Method of finish machining the surface of irregularly shaped fluid passages |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000570466A CA1310189C (en) | 1988-06-27 | 1988-06-27 | Method of finish machining the surface of irregularly shaped fluid passages |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1310189C true CA1310189C (en) | 1992-11-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000570466A Expired - Lifetime CA1310189C (en) | 1988-06-27 | 1988-06-27 | Method of finish machining the surface of irregularly shaped fluid passages |
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| Country | Link |
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| CA (1) | CA1310189C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116285896A (en) * | 2023-03-22 | 2023-06-23 | 南京航空航天大学无锡研究院 | A liquid abrasive for additive manufacturing of special-shaped parts and preparation method thereof |
-
1988
- 1988-06-27 CA CA000570466A patent/CA1310189C/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116285896A (en) * | 2023-03-22 | 2023-06-23 | 南京航空航天大学无锡研究院 | A liquid abrasive for additive manufacturing of special-shaped parts and preparation method thereof |
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