DK150717B

DK150717B - Wear-resistant impeller, specifically for use as a sprocket for sputtering of highly abrasive material or as a rotor wheel in a centrifugal type agitator or pump

Info

Publication number: DK150717B
Application number: DK543476AA
Authority: DK
Inventors: Orla Straarup; Klaus Erik Gude
Original assignee: Niro Atomizer As
Priority date: 1976-12-02
Filing date: 1976-12-02
Publication date: 1987-06-01
Also published as: DK150717C; DK543476A

Description

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Patent nr. 138.344 angår et slidfast løbehjul, navnlig til brug som forstøverhjul til forstøvning af opslemninger af stærkt slidende materiale eller som rotorhjul i en omrører eller pumpe af centrifugaltypen, indeholdende et centralt nav og et hermed koncentrisk, ringformet skålformet rum, der afgrænses af hjulets hovedsageligt cylindriske sidevæg, hvori der er udformet et antal udslyngningsåbninger foret med slidfaste bøsninger, samt af et omkring navet anbragt omdrejningslegeme og af en, hjulets bund dækkende, ringformet plade af slidfast sintret materiale.Patent No. 138,344 relates to an abrasion-resistant impeller, in particular for use as an atomizer wheel for atomizing slurries of highly abrasive material or as a rotor wheel in a centrifugal-type agitator or pump containing a central hub and a concentric annular cup-shaped space defined by the wheel. mainly cylindrical sidewalls, in which a plurality of projecting openings are lined with abrasion-resistant bushes, and of a rotating body arranged around the hub and of a wheel-bottom annular plate of wear-resistant sintered material.

Ifølge hovedpatentet er et sådant løbehjul ejendommeligt ved, at den ringformede sintrede plade er fastspændt forneden ved inder- Λλπ nf Λλϊ-ι V* ΛνττΛ/ί tr< o γτλ 1 Ί rr4- λττ Ί η O ΐ /1ΩΤΤΏΓΓ ΛΓΓ Ί ΜτΠ" *ΐ ΓΓ+- Vinl 150717 2 i afstand fra hjulbunden, og at det nævnte omdrejningslegeme er aksialt forskydeligt på navet.According to the main patent, such a impeller is peculiar in that the annular sintered plate is clamped at the bottom by inner Λλπ nf Λλϊ-ι V * ΛνττΛ / ί tr <o γτλ 1 Ί rr4- λττ Ί η O ΐ / 1ΩΤΤΏΓΓ ΛΓΓ Ί Μτ ΐ ΓΓ + - Vinl 150717 2 spaced from the wheel bottom and said rotary body is axially displaceable on the hub.

I forhold til de fra beskrivelserne til de danske patenter nr. 117.820 og 124.566 samt til dansk patentansøgning nr. 6521/73 kendte løbehjul af samme art opnås herved, at faste partikler fra opslemningen ikke kan trænge ind mellem pladens ydre periferi og indersiden af sidevæggen, og at sidevæggen samtidigt kan følge nedbøjning af hjulbunden uden deformationspåvirkning af den sintrede plade, hvilket medfører en ganske betydelig forlængelse af levetiden for et forstøverhjul af den omhandlede art.Compared to the known impellers of the same kind known from the specifications of Danish Patents Nos. 117,820 and 124,566 and to Danish Patent Application No. 6521/73, the result is that solid particles from the slurry cannot penetrate between the outer periphery of the plate and the inside of the sidewall. and that the sidewall can simultaneously follow deflection of the wheel bottom without deformation influence of the sintered plate, which results in a very considerable extension of the life of a nebulizer wheel of the kind in question.

Idet det har vist sig, at den nævnte virkning og den heraf følgende forlængelse af levetiden også kan opnås på anden måde end angivet i hovedpatentet er et slidfast løbehjul af den nævnte art ifølge opfindelsen ejendommeligt ved, at den ringformede sintrede plade er holdt i afstand fra hjulbunden, og at der er tætsluttende forbindelse mellem pladens ydre periferi og den neder ste del af indersiden af den hovedsageligt cylindriske sidevæg, hvorhos pladen er monteret mellem navet og sidevæggen med fast forbindelse til den ene af disse to dele og mulighed for relativ bevægelse i forhold til den anden del, idet løbehjul som angivet i patent nr. 138.344 er undtaget herfra.While it has been found that the said effect and the consequent extension of the lifetime can also be obtained by other means than in the main patent, a wear-resistant impeller of the kind according to the invention is peculiar in that the annular sintered plate is kept away from the bottom of the wheel, and that there is a tight connection between the outer periphery of the plate and the lower part of the interior of the substantially cylindrical sidewall, the plate being mounted between the hub and the sidewall with fixed connection to one of these two parts and the possibility of relative movement in relation to one another. to the second part, except that the impeller as disclosed in patent 138.344.

Ved en udførelsesform for løbehjulet ifølge den foreliggende opfindelse opnås en enkel og forholdsvis billig fremstilling ved, at den ringformede sintrede plade er fastspændt ved hjulets nav, og at der mellem pladens ydre periferi og indersiden af den hovedsageligt cylindriske sidevæg er anbragt en pakningsring, der tillader relativ bevægelse mellem sidevæggen og pladen. Der bliver herved mulighed for relativ bevægelse direkte mellem den ydre periferi af den sintrede plade og hjulets sidevæg, således at der til undgåelse af deformationspåvirkning af den sintrede plade ikke behøver at træffes særlige foranstaltninger til forbindelse af den sintrede plade med det nævnte omdrejningslegeme, der sædvanligvis er stål.In one embodiment of the impeller according to the present invention, a simple and relatively inexpensive manufacture is obtained in that the annular sintered plate is clamped at the wheel hub and that a gasket ring is provided between the outer periphery of the plate and the inside of the substantially cylindrical sidewall. relative movement between the side wall and the plate. This allows relative movement directly between the outer periphery of the sintered plate and the sidewall of the wheel, so that, in order to avoid deformation of the sintered plate, no special measures need be taken to connect the sintered plate with said rotary body, which is usually is steel.

Opfindelsen forklares i det følgende nærmere under henvisning til tegningen, hvor fig. 1 viser et forstøverhjul installeret i et spraytørringsanlæg , og fig. 2 og 3 viser aksiale snitbilleder af en udførelsesform for forstøverhjulet ifølge opfindelsen, henholdsvis i ubelastet tilstand og med en antydet nedbøjning af hjulbunden.The invention will now be explained in more detail with reference to the drawing, in which 1 shows an atomizer wheel installed in a spray drying system, and FIG. Figures 2 and 3 show axial sectional views of an embodiment of the atomizer wheel according to the invention, respectively in unstressed condition and with a suggested bending of the wheel bottom.

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Fig. 1 på tegningen viser et spraytørringsanlæg af den art, der f.eks. er kendt fra beskrivelsen til dansk patent nr. 129.602. Gennem et føderør 1 føres en opslemning af et stærkt slidende materiale til et forstøverhjul 2, der er installeret foroven i et tørrekammer 3, i hvis bund der gennem et rør 4 indføres en tørregas, f.eks. i form af røggas. Fra tørrekammeret 3 bortledes røggassen gennem et rør 5 til en cyklone 6, medens det spraytørrede produkt udtages gennem en tragt 7 i tørrekammeret 3's bund og et til dennes bund sluttet udledningsrør 8, hvortil der også er sluttet et forbindelsesrør til en udslusningsanordning 9 i cyklonen 6's bund.FIG. 1 of the drawing shows a spray drying plant of the kind which e.g. is known from the specification of Danish Patent No. 129,602. Through a feeding tube 1, a slurry of a highly abrasive material is passed to a nebulizer wheel 2 installed at the top of a drying chamber 3, in the bottom of which a drying gas, through e.g. in the form of flue gas. From the drying chamber 3, the flue gas is discharged through a pipe 5 to a cyclone 6, while the spray-dried product is withdrawn through a funnel 7 in the bottom of the drying chamber 3 and a discharge pipe 8 connected thereto, to which a connecting pipe is also connected to a leaching device 9 in the cyclone 6. bottom.

Under anlæggets drift roterer forstøverhjulet 2 med betydelig hastighed samtidigt med, at hjulets bund udsættes for varmepåvirkning fra den gennem røret 4 tilførte tørregas, der kan have en temperatur på 1200-1400°C. Herved vil hjulets bund blive nedbøjet ved periferien.During operation of the system, the nebulizer wheel 2 rotates at considerable speed, at the same time as the bottom of the wheel is subjected to heat pressure from the drying gas supplied through the pipe 4, which may have a temperature of 1200-1400 ° C. This will lower the bottom of the wheel at the periphery.

Ved kendte forstøverhjul af den art, der f.eks. er omhandlet i beskrivelserne til de førnævnte danske patenter nr. 117.820 og 124. 566, vil denne belastning af hjulbunden medføre, at den sintrede bundplade, der for at modstå slidpåvirkning fra det opslemmede materiale i hjulets skålformede rum er anbragt oven på selve hjulbunden, som følge af den førnævnte faste indspænding mellem hjulets nav og periferi udsættes for større trækspændinger, end det sintrede materiale kan tåle, således at pladen efter forholdsvis kort tids drift viser tilbøjelighed til at revne langs radier.In known atomizing wheels of the kind which e.g. are disclosed in the descriptions of the aforementioned Danish patents Nos. 117,820 and 1244. 566, this load on the wheel bottom will result in the sintered bottom plate which, in order to withstand wear and tear from the suspended material in the bowl-shaped compartment of the wheel, is placed on top of the wheel bottom itself, which as a result of the aforementioned fixed tension between the hub and periphery of the wheel is subjected to greater tensile stresses than the sintered material can withstand, so that the plate, after a relatively short period of operation, shows a tendency to crack along radii.

Dette problem afhjælpes ved forstøverhjulet ifølge opfindelsen, hvoraf en udførelsesform er vist i fig. 2. Det viste hjul har i princippet den udformning, der for eksempel er kendt fra beskrivelsen til dansk patent nr. 124.566. Hjulets hovedsageligt plane bund 10 er ved hjælp af et centralt nav 11 fastgjort på enden af en aksel 12, hvis frie ende stikker gennem bunden 10, og hvorpå der er skruet en møtrik 13. Til hjulbunden 10's periferi er ved hjælp af skruer 14 fastgjort hjulets cylindriske sidevæg 15*, hvori der i det viste eksempel er udformet to rækker udslyngningsåbninger, som angivet ved 16 og 17, hvilke udslyngningsåbninger er foret med bøsninger 18 af slidfast, f.eks. sintret materiale og indsat i stålbøsninger 19 på en sådan måde, at de slidfaste bøsninger 18 rager et stykke inden for indersiden af sidevæggen 15', således som det er kendt fra beskrivelsen til det sidstnævnte patent. Til overkanten af den cylindriske sidevæg 15 er ved hjælp af skruer 21 fastgjortThis problem is remedied by the atomizer wheel according to the invention, an embodiment of which is shown in FIG. 2. The wheel shown in principle has the design known, for example, from the specification of Danish Patent No. 124,566. The substantially flat bottom 10 of the wheel is secured by means of a central hub 11 to the end of a shaft 12, the free end of which extends through the bottom 10 and on which is screwed a nut 13. To the periphery of the wheel bottom 10 is secured by means of screws 14 cylindrical sidewall 15 * wherein in the example shown two rows of projecting openings are formed, as indicated at 16 and 17, which projecting openings are lined with wear-resistant bushings 18, e.g. sintered material and inserted into steel bushings 19 in such a way that the wear-resistant bushings 18 protrude within the interior of the side wall 15 ', as is known from the specification of the latter patent. To the top of the cylindrical sidewall 15 is secured by screws 21

Claims

The annular cover plate 20 of the wheel, which has in the center about the shaft 12, an aperture for placing a funnel 22, which is only illustratively illustrated, for supplying the suspended material to be treated in the atomizer wheel. The interior of the wheel around the hub 11, in a known manner, forms an annular cup-shaped space, which is defined inwardly by a shaft 12 and the upper part of the hub 1, arranged in the embodiment shown mainly conical rotating body 23 'and downwards to withstand wear and tear of a hub. annular plate 24 'of sintered material, e.g. alumina, tungsten carbide or silicon carbide. In the illustrated embodiment, the annular sintered plate 24 'is clamped at the hub of the wheel, having an inwardly facing collar 33, the underside of which rests against a shoulder-shaped ledge 34 of the hub 11 over an intermediate packing ring 35, while its upper side forms abutment. for the underside of the tapered rotary body 231 screwed directly onto the upper end of the hub 11 having an external thread 37 thereto, a sealing ring 36. Also provided between the upper face of the collar 33 and the underside of the body 23 the outer periphery of the plate 24 'is provided in a circumferential groove at the inner side of the substantially cylindrical side wall 15' of a gasket ring 38 which at the same time prevents solid particles from slurry from entering the space between the side wall 15 'and the plate 24 'and allows relative movement between the sidewall 15' and the plate 24 'to allow the sidewall as shown in FIG. 3 can follow deflection of the wheel bottom 10 without deformation of the sintered plate 24 'which is clamped to the hub. The outer shape of the sintered plate 24 ', as with the impeller according to the main patent, may advantageously be such that the underside facing the wheel bottom is substantially planar while the upper surface is hyperboloid shaped and together with the side surface of the tapered rotary body 23' forms an unbroken, inner trumpet-shaped restriction wall in the bowl-shaped compartment of the wheel.

1. Durable impeller, in particular for use as an atomizer wheel for atomizing slurries of highly abrasive material or as a rotor wheel in a centrifugal type stirrer or pump, comprising: