DK172985B1

DK172985B1 - Centrifugal pump, especially for heavy manure

Info

Publication number: DK172985B1
Application number: DK97496A
Authority: DK
Inventors: Ole Horsager
Original assignee: Ansager Staldrens
Priority date: 1996-09-10
Filing date: 1996-09-10
Publication date: 1999-11-01
Also published as: AU4199697A; DE19781992T1; DK97496A; WO1998011352A1

Description

i DK 172985 B1in DK 172985 B1

Den foreliggende opfindelse angår en centrifugalpumpe og i første række en gyllepumpe til svær gylle. Der er i den forbindelse typisk tale om et pumpeaggregat med en øvre bære-del, som fastholder et motor- eller gearhus, hvorfra der 5 strækker sig et akselrør et godt stykke nedad til et pumpe-hus, der i sin underside har en central indtagsåbning og i øvrigt er udformet som et centrifugalpumpehus med et tangen-tialudløb, som er tilsluttet et opadførende stigror. Dette strækker sig parallelt med akselrøret op til bæredelen, hvor 10 det fastholdes og er afsluttet med en rørbøjning, hvortil der kan sluttes en videreførende slange. Gennem akselrøret strækker sig en drivaksel, som driver en pumperotor i form af en cirkulær plade med nedragende skovlplader indvendigt i pumpehuset .The present invention relates to a centrifugal pump and, first of all, to a heavy manure slurry pump. In this connection, it is typically a pump assembly with an upper support part which retains a motor or gear housing, from which a shaft extends a good distance downwards to a pump housing having a central inlet opening at its bottom side. and, moreover, is configured as a centrifugal pump housing with a forceps-tial outlet, which is connected to an upwardly extending stirrer. This extends parallel to the shaft tube up to the support portion, where it is retained and terminated by a tube bend to which a further hose may be attached. A drive shaft extends through the shaft tube, which drives a pump rotor in the form of a circular plate with projecting vane plates inside the pump housing.

15 Aggregater af denne type benyttes typisk til overpumpning af gylle mellem to tanke, dvs. pumpen bør have en sådan ydelse, at den ikke alene kan presse gyllen op til den afleverende rørbøjning, men også vidretrykke gyllen gennem et slangestykke af mærkbar længde.Aggregates of this type are typically used for over-pumping manure between two tanks, ie. the pump should have a performance such that it can not only push the slurry up to the delivering pipe bend, but also push the slurry through a hose piece of appreciable length.

20 Det er en almindelig erfaring, at den slags pumper kan drives til præstering af et pumpetryk på ca. 2 bar, hvilket er i underkanten af det ønskelige for etablering af et godt afleveringsflow fra pumpen. Der er foreslået mange forskellige radialforløb af rotorens skovlplader, fra lige udstående 25 forløb til kraftigt bagudbøjede forløb i forhold til rotationsretningen, ligesom det er forsøgt at øge rotationshastigheden og/eller rotordiameteren ud over de gængse værdier, som typisk er henholdsvis ca. 1.000 omdr./min. og ca. 0 50 cm.It is a common experience that such pumps can be operated to achieve a pump pressure of approx. 2 bar, which is at the lower end of the desirable for establishing a good delivery flow from the pump. Many different radial paths of the rotor vane blades have been proposed, from equally protruding 25 to strongly backward bending relative to the direction of rotation, and attempts have been made to increase the rotational speed and / or rotor diameter beyond the usual values, which are typically approx. 1,000 rpm and approx. 0 50 cm.

Der er ved sådanne tiltag opnået visse marginale forbedrin-3 0 ger, men dog ikke mere end at pumpetrykket fortsat kan angives som værende "ca. 2 bar".Such measures have achieved some marginal improvements, but no more than that the pump pressure can still be stated as being "about 2 bar".

I forbindelse med opfindelsen har det været særligt påfaldende, at det ikke nytter stort at øge rotationshastigheden af pumperotoren. Dette må udlægges derhen, at der optræ-35 der et kavit at ionsproblem bestående i, at der ved bagsiderne af skovlvingene opbygges et vacuum, som bliver desto mere udpræget, jo hurtigere rotationen foregår, henholdsvis jo større rotordiameteren er. Dette vacuum optræder som en direkte DK 172985 B1 2 modkraft imod motorens rotation, således at der for en for-j øgelse af pumpeydelsen skal tilføres urealistisk megen ener- gi.In connection with the invention, it has been particularly striking that it is not of great use to increase the rotational speed of the pump rotor. This must be interpreted there as a cavity problem, in that a vacuum builds up at the rear of the vane blades, which becomes the more pronounced the faster the rotation takes place and the larger the rotor diameter, respectively. This vacuum acts as a direct counter-force to the rotation of the motor, so that for an increase in pump performance unrealistically high energy must be supplied.

j På denne baggrund er det ved opfindelsen overvejet, hvor- | 5 ledes det nævnte kavi tat ionsproblem kan undgås, og det er herved fundet, at dette er opnåeligt ved en særlig profilering af skovlpladerne set i disses omdrejningsretning mere end i deres radialretning. Der vælges fortrinsvis et kun svagt buet radial forløb af de aktive skovlplader, men det me-10 re væsentlige er, at der ved bagsiden af skovlpladerne er anbragt skråtstillede udfyldningsplader, der fra den frie bagsidekant af hver skovlplade strækker sig bagud/indad mod rotorpladen på en sådan måde, at vingetværsnittet generelt har udpræget trekantform, nemlig med en i omløbsretningen stejlt-ϋ 15 stående forside og en derfra markant bagudskrånende bagside.In view of the foregoing, it is contemplated by the invention how- | 5, the said cavitation problem can be avoided and it is found that this is attainable by a special profiling of the vane plates seen in their direction of rotation more than in their radial direction. Preferably, only a slightly curved radial course of the active vane plates is selected, but more importantly, at the rear of the vane plates, inclined fill plates are provided which extend from the free rear edge of each vane plate rearward / inward toward the rotor plate of in such a way that the wing cross-section generally has a distinct triangular shape, namely with a steeply-ϋ 15 front face and a marked rearwardly inclined rear side therefrom.

Det er dog netop ved gyllepumper fundet vigtigt, at skovlvingerne ved deres indvendige ender danner en kilefor-mig, skærende kant beliggende i en vis afstand fra rotorpladens centrum. Fortrinsvis skal denne kant være skråtstillet i 20 radialt udadgående retning bort fra rotorpladen, og dette rimer udmærket med, at den enkelte skovlplade ved sin bagside kan være forsynet med den nævnte skrånende bagplade på en sådan måde, at denne ved også at være radialt indadskrånende fra vingens ydre ende ind til den indre ende af vingen kan 25 være bagudskånende og dog møde den indre vingekant i en skarp og ligefrem skærpet vinkel. Set vinkelret ind mod rotorpladen vil således den enkelte skovlvinge være trekantformet, med en i rotationsretningen stejltstående forplade og en derfra bagudskrånende bagplade, som yderst er langt bagudskrånende fra 30 vingepladen og inderst danner en skarp vinkel dermed.However, it is precisely found by slurry pumps that the vane blades at their inner ends form a wedge-shaped, cutting edge located at some distance from the center of the rotor plate. Preferably, this edge must be inclined in a radially outward direction away from the rotor plate, and this rhymes well with the fact that the individual vane plate at its rear can be provided with said inclined rear plate in such a way that it can also be radially inwards from the outer end of the wing to the inner end of the wing can be rearward-facing and yet meet the inner wing edge at a sharp and even sharpened angle. Thus, viewed perpendicular to the rotor plate, the individual blade blade will be triangular in shape, with a steeply facing face in the direction of rotation and a rearwardly sloping backplate, which is extremely far backwardly inclined from the blade plate and at the very least forms a sharp angle thereof.

Det for opfindelsen mere væsentlige er, at den skrånende vingebagside helt øjensynligt medfører en mærkbar svækkelse af kavi tat ionsvirkningen, idet det er konstateret, at en pumpe udført i henhold til opfindelsen kan præstere et pumpetryk 35 på omkring det dobbelte af det hidtil accepterede, hvor ellers forbedringer på blot ganske få procent er opfattet som bemærkelsesværdige.More important for the invention is that the sloping wing back side evidently causes a noticeable weakening of the cavitation effect, as it is found that a pump made according to the invention can produce a pump pressure 35 of about twice that previously accepted, where otherwise improvements of just a few percent are considered notable.

DK 172985 B1 3DK 172985 B1 3

Det er endda fundet relevant, at man for opnåelse af det forhøjede pumpetryk benytter en rotor med en lidt mindre diameter end normalt, f.eks. blot 40 cm. Ved samme krafttilførsel vil så rotoren snurre lidt hurtigere, men nu uden at 5 kavitationsproblemet forringer det forbedrede resultat mærkbart .It has even been found relevant that in order to achieve the elevated pump pressure a rotor with a slightly smaller diameter than normal, e.g. just 40 cm. At the same power supply then the rotor will spin slightly faster, but now without the cavitation problem, the improved result noticeably deteriorates.

Opfindelsen forklares i det følgende nærmere under henvisning til tegningen, på hvilken fig. 1 er et nedefra set perspektivbillede af et pumpeag-10 gregat af relevant kendt type, fig. 2 et planbillede af pumperotoren deri, fig. 3 et perspektivisk billede af samme, fig. 4 et perspektivbillede af en enkelt pumpeskovl på denne rotor, og 15 fig· 5 et planbillede af en foretrukket skovlform.The invention will now be explained in more detail with reference to the drawing, in which: FIG. 1 is a bottom perspective view of a pump assembly 10 of relevant known type; FIG. 2 is a plan view of the pump rotor therein; FIG. 3 is a perspective view of the same; FIG. 4 is a perspective view of a single impeller on this rotor; and FIG. 5 is a plan view of a preferred impeller.

Det i fig. 1 viste pumpeaggregat omfatter et centrifugal-pumpehus 2, som har et ikke vist pladeloft og er afsluttet opadtil med en konisk topplade 4, samt et tangentialudløb 6, hvorfra et afgangsrør 8 strækker sig op til en øvre bæredel 20 10, ved hvilken dette rør fortrinsvis er videreført i en rør bøjning 12 for tilkobling til en ikke vist slange. Bæredelen 10 fastholder desuden en drivenhed 14, der kan være en elektromotor eller en hydraulikmotor, henholdsvis en gearkasse, drevet ved tilslutning til et hydraulisk eller mekanisk 25 kraftudtag på en traktor. Mellem denne drivenhed 14 og toppen af pumpehuset 2 er anbragt et akselrør 16, gennem hvilket der strækker sig en drivaksel til drift af en i pumpehuset 2 lejret pumperotor 18. Så vidt beskrevet er dette aggregat helt konventionelt.The FIG. 1, a pump assembly 2 comprises a centrifugal pump housing 2 which has a plate ceiling not shown and is closed upwardly with a conical top plate 4, and a tangential outlet 6, from which a discharge pipe 8 extends up to an upper support part 20, whereby this pipe is preferably is carried on in a pipe bend 12 for connection to a hose not shown. In addition, the carrier portion 10 maintains a drive unit 14 which may be an electric motor or a hydraulic motor or a gearbox, respectively, driven by connection to a hydraulic or mechanical 25 PTO on a tractor. Between this drive unit 14 and the top of the pump housing 2 is arranged a shaft tube 16 through which extends a drive shaft for operating a pump rotor 18, which is mounted in the pump housing 2.

30 Pumperotoren 18 er som vist i fig. 2 og 3 en cirkulær plade 20, der ligger øverst i pumpehuset 2 og er forsynet med lige nedragende skovlblade 22, der på kun let buet måde strækker sig fra et punkt PI på pladen 20 i kort afstand uden for dennes tilslutning 24 til den nævnte drivaksel til et 35 punkt P2 ved periferien af pladen 20. Den indadvendende kant 24 af skovlbladene 22 er afskåret på udadskrånende måde på strækningen mellem Pi og et ydre mellempunkt P3. Denne afskæ- DK 172985 B1 4 ring kan dog eventuelt forløbe gennem en buet overgang i stedet for gennem et knækpunkt P3.The pump rotor 18 is shown in FIG. 2 and 3 is a circular plate 20 which is located at the top of the pump housing 2 and is provided with straight protruding vane blades 22 which extend in a slightly curved manner only from a point P1 on the plate 20 for a short distance outside its connection 24 to said drive shaft to a 35 point P2 at the periphery of the plate 20. The inward edge 24 of the vane blades 22 is cut outwardly on the line between Pi and an outer intermediate point P3. However, this cutoff may possibly proceed through a curved transition rather than through a break point P3.

j Det for opfindelsen ekstra væsentlige er, at skovlbladene 22 ved deres frie topkanter er forbundet med bagsideplader ! 5 26, som med et mere eller mindre plant forløb strækker sig bagud til en forbindelseslinie 28 ved rotorpladen 20, hvorved denne skrå bagplade som tydeligst vist i fig. 2 vil dække et trekantområde bagved den tilhørende skovlvinge 22, med en tilhørende grundlinie vist mellem inderpunktet PI og et yder-10 punkt P4.It is particularly important for the invention that the vane blades 22 at their free top edges are connected to backing plates! 5 26, which extends rearwardly to a connecting line 28 at the rotor plate 20 with a more or less flat course, whereby this inclined back plate as most clearly shown in FIG. 2 will cover a triangle area behind the associated vane blade 22, with an associated baseline shown between the inner point P1 and an outer point P4.

Det er herved en bestående mulighed, at det indre forkantparti 24 kan fremstå i kantskærpet form, således at denne kant ved rotationen af rotoren 18 kan virke sønderdelende på grovklumper i den pumpede gylle.Hereby, there is a permanent possibility that the inner leading edge portion 24 may appear in edge-sharpened form, so that this rotation, during rotation of the rotor 18, may disintegrate on coarse chunks in the pumped slurry.

15 Imidlertid er det en konstateret hovedvirkning, at de bagudskrånende dækplader 26 bevirker en så mærkbar reduktion af kavitationseffekten i pumpen, at denne på overraskende måde er i stand til at yde et stort set fordoblet pumpetryk.However, it is a major effect that the backward-facing cover plates 26 produce such a noticeable reduction in the cavitation effect in the pump that it is surprisingly capable of providing a substantially doubled pump pressure.

Oven i købet er dette opnåeligt ved brug af en reduceret 20 diameter af pumpehuset 2 og rotoren 18, hvorved der endda er tale om en billiggørelse af konstruktionen.In addition, this is attainable by the use of a reduced diameter 20 of the pump housing 2 and the rotor 18, thereby even lowering the construction.

Det er ved opfindelsen en oplagt mulighed, at der kan spekuleres og eksperimenteres med den nærmere formgivning af såvel skovlpladerne 22 som disses bagplader 26, og opfindel-25 sen rummer ingen begrænsning i så henseende. Det kan nævnes, at vingerne i en foretrukket udførelse jfr. fig. 5 har det nævnte knækkede forløb af skovlpladen 22, medens bagpladen 26 har et buet forløb, ved hvilket den ikke når helt ud til knækområdet, men til gengæld kan være fuldstændig plan.It is an obvious possibility in the invention that speculation and experimentation can be speculated upon with the design of both the blade plates 22 and their back plates 26, and the invention 25 has no limitation in this regard. It may be mentioned that the wings of a preferred embodiment cf. FIG. 5, said broken course of the vane plate 22, while the back plate 26 has a curved course, in which it does not reach all the way to the crack region, but in turn can be completely flat.

30 Opfindelsen rummer et yderligere aspekt ved brugen af det fra pumpehuset konisk opragende loft 4, idet denne detalje er medvirkende til, at der på oversiden af pumpehuset 2 ikke kan aflejres gylleklumper, som nu naturligt vil ledes ned til den aktive underside af pumpehuset, hvor sådanne klumper kan ind-35 ledes til rotoren 18 gennem en nedre, central åbning 3 i en udefra indragende bundplade 5, fig. 1. Det kan dog foretrækkes, at der ved overgangen mellem den nævnte loftplade og rotorhuset 2 forekommer boltesamling, som er let at adskille DK 172985 B1 5 for afmontering af huset 2 og rotoren 18, ifald denne skal tilses eller repareres.The invention includes a further aspect of the use of the ceiling 4 conical projecting from the pump housing, this detail contributing to the fact that on the upper side of the pump housing 2 slurry lumps cannot be deposited, which will now naturally be directed down to the active underside of the pump housing, where such lumps may be introduced to the rotor 18 through a lower central opening 3 in an externally projecting base plate 5; 1. However, it is preferable that at the transition between said ceiling plate and the rotor housing 2 there is a bolt assembly which is easily separable for removal of the housing 2 and the rotor 18, if it has to be inspected or repaired.

Som nævnt er opfindelsen især knyttet til gyllepumper, men den vil dog ligesåvel være relateret til alle mulige an-5 dre væskepumper i den udstrækning det er nyt at supplere rotorskovlene med de bagsidedækkende skråplader 26.As mentioned, the invention is particularly related to slurry pumps, but it will however also be related to all possible other liquid pumps to the extent that it is new to supplement the rotor vanes with the rear cover slanting plates 26.

Claims

A centrifugal pump especially for slurry and corresponding "heavy" fluids, with a rotating impeller disc carrying protruding radial ribs which form pump wings which may be more or less curved in the radial direction, characterized in that the radial ribs seen in the rotational direction are designed with a conventional face steeply raised from the wheel disc in conventional manner while at the rear they are provided with a rearwardly inclined cross-sectional profile.

Pump according to claim 1, characterized in that a sloping back plate extends in such a way that it occupies a markedly sloping position relative to the steep front of the rib, while inwardly meeting the surface of the wing 15 at a sharp edge near the center of the impeller disc , but at a radial distance therefrom and preferably with an outward sloping edge.

Pump according to claim 1, characterized in that the diameter of the pump disk is relatively small, namely preferably only approx. 40 cm.