CA1205682A

CA1205682A - Start-up device for multistage pumps and turbopumps with steady diffuser

Info

Publication number: CA1205682A
Application number: CA000379119A
Authority: CA
Inventors: Pierre Boussuges
Original assignee: Neyrpic SA
Current assignee: Neyrpic SA
Priority date: 1980-06-06
Filing date: 1981-06-05
Publication date: 1986-06-10
Also published as: FR2484025A1; FR2484025B1; AR224073A1; BR8103231A

Abstract

PRECIS DE LA DIVULGATION:

Pompe ou turbine-pompe multiétages à diffuseur fixe et démarrant roues noyées, comprenant: un dispositif auxiliaire placé au-niveau de l'étage inférieur, cet étage inférieur comprenant une roue suivie d'un diffuseur fixe.
Des moyens sont prévus dans ce dispositif auxiliaire pour créer un grand nombre de jets d'eau sous pression créant un écran d'eau dans un espace annulaire situé entre la sortie de la roue et le diffuseur. Des moyens sont égale-ment prévus pour effectuer un démarrage de la pompe soit à
débit partiel soit à débit nul. Cette disposition permet de diminuer la puissance de barbotage au cours du démarrage roues noyées. PRECISION OF DISCLOSURE:

Diffuser multi-stage pump or turbine-pump fixed and starting wet wheels, comprising: a device auxiliary placed on the lower level, this level lower comprising a wheel followed by a fixed diffuser.
Means are provided in this auxiliary device for create a large number of pressurized water jets creating a water screen in an annular space located between the wheel outlet and diffuser. Means are also provided to start the pump either at partial flow or zero flow. This provision allows reduce the bubbling power during start-up drowned wheels.

Description

~S68~
La presente in~e~tion se rapporte aux pompes et tur-bines-~ompes multietages a difEuseur ~ixe utilisees dans les ins-tallations hydroelectriques, et concerne plus specialement un dispositif permettant dlen faciliter le demarrage.
Le demarrage des pompes ou des turbines-pompes en pompe, lorsque ces machines sont à plusieurs etages et a diffu-seurs fixes, s~effectue actuellement toujours roues no~ees, au~
tant en raison des difficultes que rencontrerait dans llautre cas l'implantation de tuyauteries de vidange dleau et d'amenee d~air comprime, qu~en raison des probl~mes que creeraient les instabili-tes qui seraient dues à l'evacuation brutale de l'air sous la pous-see de l'eau au moment du renoya~e.
La sequence classique de demarrage de telles pompes ou turbines-pom.pes consiste, le robinet de garde etant ~e~me, a dé-marrer la pompe soit à l'aide.d'un moteur synchrone auxiliaire, soit à l'aide de son moteur synchrone fonctionnant alors, gr~ce à des equipements speciaux ou à un surdimensionnement des bobina-~es du rotor, en moteur synchrone. On augmente alors progressi-vement la vitesse jusqu~ parvenir à la vitesse de s~nchronisme.
On couple alors le moteur synchrone et l~on ouvre progressivement le robinet de garde jusqu'à ce ~e l~on obtienne le debit no~inal.
La puissance fournie à debit nul au voisinage de la ~itesse de synchronisme, appelee " puissance de barbotage" est souvent, dans le cas des pompes à diffuseurs fixes, une fraction non négligea-ble de la puissance nominale, et peut atteindre 90~ de celle~
Il en résulte d'une part un echauffement de l~eau ~ debit nul ~ui risque d'entralnerl par une dilatation differentielle de certaines pièces de la turbine entre parties fixes et parties mobiles, l'en-dommagement de certaines de ces pieces, et d~autre part une neces-sité de surdimensionnement du moteur utilisé pour le demarrage,que celui-ci soit un moteur auxiliaire, le rnoteur principal de la turbine-pompe, ou le moteur synchrone principal de la pompe slil 1, ,.~, . .

~L2~

s'agit d'une pompe classique.
Selon la présente invention, il est prévu une pompe ou turbine-pompe multiétages à diffuseur fixe et démarrant roues noyées, comprenant:
- un dispositif auxiliaire placé au-niveau de l'étage inférieur, cet étage inférieur comprenant une roue suivie d'un diffuseur fixe, - des moyens prévus dans ce dispositif auxiliaire pour créer un grand nombre de jets d'eau sous pression créant un écran d'eau dans un espace annulaire situé
entre la sortie de la roue et le diffuseur, - des moyens pour effectuer un démarrage de la pompe soit à débit partiel soit à débit nul.
~'écran d'eau ainsi créé limite alors au dëmarrage le frottement fluide sur le diffuseur fixe relatif à
l'étage considéré, ainsi que les recirculations à travers les aubages dudit diffuseur, ce qui permet de diminuer de manière non négligeable le couple de barbotage.
L'invention sera mieux comprise à l'aide de la description suivante d'un exemple de réalisation non limitatif, appliqué au démarrage en pompe d'une turbins-pompe à trois étages et à diffuseurs fixes, en référence aux dessins annexés dans lesquels:
- la figure 1 est une vue schématique en coupe longitudi-nale de la turbine-pompe de l'invention, - la figure 2 est une représentation schématique agrandie du dispositif d'injection de jets d'eau équipant la pompe de la figure 1, - la figure 3 est une vue développée de l'anneau d'in-jection de jets d'eau équipant le dispositif d'injection de la figure 2, - la figure 4 est une vue développée d'une variante d'anneau dlinjection pouvant équiper le dispositif d'injection de la fi-~2C~5S~Ad gure 2~
- la fi~ure 5 represente sc~emati~uement une.var.iante de dispo-sitif a'i~jection de iets d'eau pou~ant equiper la pompe de la figure 1, - la fi~ure 6 est une vue developpee du tronc de cone dlinjec~
tion de jets d'eau equipant-le dispositif d'injection de la figure 5.
On reconnait sur la representation schematique de la figure 1 une turbine-pompe hydroelectrique a trois éta~es, com-portant, dans le sens de l'ecoulement lorsque la machine, comme c'est le cas pour l'invention, fonctionne en pompe:
- un aspirateur 1 dlarrivee d'eau, - un premier etage comportant une roue a aubes 2 suivie d'un diffuseur fixe 3, - un premier circuit de retour 4 servant à amener l'eau vers 1 second etage, - un second etage comportant une roue à aubes 5 et un diffuseur fixe 6, - lln second circuit de retour 7 permettant d'amener l'eau jus~
qu'au troisième etage, - un troisième et dernier etage comportant une roue a aubes 8 et un diffuseur fixe 9, - un clrcuit de sortie, ou " bache" , comportant u~ avant-dif-fuseur 10 et une volute 11, une conduite forcee de refoulement 12 munie d'un robinet de ~arde 13.
L'ensemble de ces elements, ~ l'exception de l'aspi--rateur et de la volute qui sont dissymetriques, est par ailleurs de revolution autour de l'arbre 14 de la machin~.
Conformément ~ l'invention, l'eta~e in~erieur de ~a machine est muni d'un dispositif perme~-tant d'injecter de bas en haut et parallelement a l'arbre 14, une centaine de jets dleau 12~S~ 2 SOU5 press'io~ 16 dans ~lespace an~ulaire 15 separant la roue 2 du diffuseur 3. Ce dispositif~ qui sera decrit plus en details en reference aux ~igures 2 et 3 est constitue essen-tiellement par un anneau distributeur dleau 17, ou collecteur, muni d~une arrivee d'eau sous pression 18 et perçe a sa partie superieure d'un grand nombre de canaux 19 permettant l~ejection des jets d'eau 16. Pour amener l'eau sous pression en 18, on utilise une canalisation de dérivation 20, ou " b~-pass~ r qui raccorde l'entrée 18 ~ la conduite d'évacuation 12, soit en 21 ~ l'amont du robinet de garde 13, soit en 22 a l~aval de celui-ci, selon que les robinets sphériques 23 et 24, places sur les canalisa-tions 25 et 26 sont respectivement le premier ouvert et le second ~erme ou le premier ferme et le second ouvert.
Dans le cas o~ l'on souhaitera effectuer le démarra-ge de la pompe ~ debit nul, c~est-~-dire avec le robi~et de gar-de 13 totalement ferme, on prendra la derivation de by~pass 20 en 22, donc en ouvrant le robinet 24, le robinet 23 étant fermé, la pression d'eau d'injection par les canaux 19 etant alors fonc~
tion de la hauteur de chute résiduelle par rapport au bassin su-perleur. Par contre, pour un demarrage à debit partiel, a~ec lerobinet de garde 13 leg~rement o'uvert, on prendra avantageusement la derivation en 21, le robinet 23 étant ouvext et le robinet 24 ferme, ce qui evite en particulier la perte de charge dans le robinet de garde 13.
La coupe schematique de la figure 2 montre plus en dé-tails le dispositif auxiliaire dlinjection de iet~ d~eau de la Eigure 1.
Comme on le voit sur le dessin le collecteur annulai-re 17 est constitué de deux pieces 27 et 28 La pi2ce annulaire 27 s'appuie sur le corps de l'aspirateur 1; l'étanchéité entre la partie f'ixe 27 et la roue 2 est assuree par un joint 29. Par ail-leurs, la partie superieure de la piece 27 est usi~ee de ~aniere ~2~ z à former une roue dentee 30 à dents axi~les, dont 1~ fi~ure 3 en represente une vue developpee~ ce qui permet de definir par appui sur l'autre pièce 28 une serie de canaux verticaux 19 de passage des jets 16. Comme mentionne precedemment, ~es jets d'eau sous pression 16 permettent de former, dans l~espace 15, un écran d'eau li~se permettant dlisoler la roue 2 du diffuseur 3 et de diminuer ainsi la puissance de barbotage La figure 4 montre une variante avantageuse de la roue dentée 30 de la figure 2. Selon cette variante, les dents definissant les canaux 19 sont inclinées par rapport a l~hori~
zontale d'un angle avantageusement situé aux alentours d~une txen~
taine de degres, et en tous cas inferieur à 90 degres~ de maniare a diriger les jets 16 dans le sens tendant à ~aire tourner en pom-pe les aubes de roue 2. De la sorte, les jets 16 de l~ ention ont, outre leur fonction de cration d'un ecran d~eau, une fonc-tion d'aide au demarrage de la pompe.
Les figures 5 et 6 montrent une variante du disposi-tif selon les figures 2 et 4, se differenciant de celles-ci par le fait que la roue aentée 30 est une roue tronc6nique, les ca-naux 19 etant alors non seulement inclines, comme on le voit sur la figure 6, d'environ 30 degres par rapport a l'~orizontale, mais etant en outre inclinés d'approximativement la même valeur par rapport à la verticale et vers la gauche, c'est-a-dire vers la roue 2, les deux angles d'inclinaison etant en tous cas infé-rieurs ~ 90 degrés. La demanderesse a trouvé que cette disposi-tion permettait aux jets 16 d'encore mieux assister le démarra-ge en pompe de la machine, tout en créant dans l'espace 15 un écran dleau aussi efficace que celui créé par les configurations de roues dentées 30 selon les figure~ (2, 3) et (2, 4).
Il va de soi que l~invention nlest pas ~imitée aux réalisations qui viennent d'etre décrites ~ titre d~exemple. En particulier, ces réal:isations ne comportent qu'un dispositif .

s6~z 117, l9) d~injection de jets d~eau ~ers le haut dans l~es~ace 15 place a la partie inferieure de celui-ci~ a de soi qulon pourrait aussi bien placer un te'l dispositif en outre ou unique ment à la partie superieure de cet espace 15, injectant alors des jets 16 diriges ~ers le bas. Toutefois~ une telle dispo~
sition poserait des probl8mes supplementaires d~encombrement de sorte que la disposition decrite precedemment a ete trou~ee pre~
ferentielle et d'une efficacite suffisante. On pour~ait aussi munir tout ou partie des autres etages d'un disposit.i~ de crea~
tion d~un rideau d~eau selon l'invention, mais leur efficacite serait toutefois moindre que sur lletage inferieur en raison de la diminution de la puissance des jets 16 sur les étages sui~tants~
il serait dans ce cas souhaitable d~adjoindre sur chaque canal 20 une pompe auxiliaire perme~tant d~augmenter la puissance des jets 16. ~ S68 ~
This in ~ e ~ tion relates to pumps and tur-bines- ~ multi-stage pumps with diffuser ~ ixe used in the ins-hydroelectric plants, and more specifically concerns a device to facilitate start-up.
Starting pumps or pump-turbines in pump, when these machines are multistage and diffused fixed sisters, are currently still running no ~ ees wheels, at ~
both because of the difficulties that would otherwise arise installation of water drainage and air supply pipes compresses, that because of the problems that instability would create which would be due to the brutal evacuation of the air under the push see water at the time of the reseeding.
The classic starting sequence for such pumps or turbines-pom.pes consists, the guard valve being ~ e ~ me, has de-start the pump either with an auxiliary synchronous motor, either with its synchronous motor operating then, gr ~ ce to special equipment or to oversizing of the coils-~ es of the rotor, in synchronous motor. We then gradually increase the speed until reaching the synchronization speed.
We then couple the synchronous motor and gradually open it the guard valve until ~ el ~ we get the flow no ~ inal.
The power supplied at zero flow near the ~ itesse de synchronism, called "bubbling power" is often, in the case of pumps with fixed diffusers, a significant fraction ble of nominal power, and can reach 90 ~ of that ~
This results on the one hand in a heating of the water ~ zero flow ~ ui risk of internalization by differential dilation of certain turbine parts between fixed and moving parts, the damage to some of these parts, and on the other hand a need sizing of the engine used for starting, whether this is an auxiliary engine, the main engine of the turbine pump, or the main synchronous motor of the slil pump 1, ,. ~,. .

~ L2 ~

it is a conventional pump.
According to the present invention, there is provided a fixed-stage pump or turbine-pump with fixed diffuser and starting wet wheels, comprising:
- an auxiliary device placed at the lower floor, this lower floor comprising a wheel followed by a fixed diffuser, - means provided in this auxiliary device to create a large number of pressurized water jets creating a water screen in an annular space located between the wheel outlet and the diffuser, means for starting the pump either partial flow or zero flow.
~ 'water screen thus created then limits to starting the fluid friction on the fixed diffuser relative to the stage considered, as well as the recirculations through the blades of said diffuser, which makes it possible to reduce by not negligible the bubbling torque.
The invention will be better understood using the following description of an exemplary embodiment not restrictive, applied to the pump start-up of a pump-turbine with three stages and fixed diffusers, with reference to annexed drawings in which:
- Figure 1 is a schematic view in longitudinal section -nale of the pump-turbine of the invention, - Figure 2 is an enlarged schematic representation of the water jet injection device fitted to the pump of figure 1, - Figure 3 is a developed view of the information ring jection of water jets fitted to the injection device of figure 2, - Figure 4 is a developed view of a variant ring injection which can equip the injection device with the fi-~ 2C ~ 5S ~ Ad gure 2 ~
- the fi ~ ure 5 represents sc ~ emati ~ uement une.var.iante available If the water jets can be used to equip the pump with Figure 1, - The fi ~ ure 6 is a developed view of the trunk of cone dlinjec ~
tion of water jets equipping the injection device figure 5.
We recognize on the schematic representation of the Figure 1 a hydroelectric turbine pump has three stages, bearing, in the direction of flow when the machine, as this is the case for the invention, operates as a pump:
- a vacuum cleaner 1 water supply, - a first stage comprising a paddle wheel 2 followed by a fixed diffuser 3, - a first return circuit 4 used to bring the water to 1 second floor, - a second stage comprising a paddle wheel 5 and a diffuser fixed 6, - lln second return circuit 7 for bringing the water to juice ~
that on the third floor, a third and last stage comprising a paddle wheel 8 and a fixed diffuser 9, - an output clrcuit, or "tarpaulin", comprising u ~ before-dif-fuseur 10 and a volute 11, a forced discharge line 12 fitted with a shut-off valve ~ arde 13.
All of these elements, except for the aspi--rator and volute which are asymmetrical, is also of revolution around the shaft 14 of the thing ~.
In accordance with ~ the invention, the eta ~ e in ~ erieur of ~ a machine is provided with a perme device ~ -to inject from bottom to high and parallel to the tree 14, a hundred water jets 12 ~ S ~ 2 SOU5 press'io ~ 16 in ~ space an ~ ulaire 15 separating the wheel 2 of the diffuser 3. This device ~ which will be described in more detail with reference to ~ Figures 2 and 3 is essentially constituted by a water distributor ring 17, or collector, provided with a pressure water inlet 18 and pierces at its upper part a large number of channels 19 allowing the ejection of the jets of water 16. To bring the water under pressure at 18, we use a bypass line 20, or "b ~ -pass ~ r which connects the inlet 18 ~ the evacuation pipe 12, ie at 21 ~ upstream guard valve 13, or at 22 al ~ downstream thereof, according to that the ball valves 23 and 24, placed on the pipes-25 and 26 are the first open and the second respectively ~ erme or the first farm and the second open.
In the event that we wish to carry out the start-pump ge ~ zero flow, that is ~ ~ say with the robi ~ and gar-from 13 completely firm, we will take the derivation of by ~ pass 20 at 22, therefore by opening tap 24, tap 23 being closed, the injection water pressure through the channels 19 then being functional ~
tion of the residual height of fall in relation to the pearler. On the other hand, for a partial flow start-up, at ~ ec lerobinet de garde 13 leg ~ rement o'uvert, we will take advantageously the branch at 21, the tap 23 being open and the tap 24 closes, which in particular prevents pressure drop in the guard valve 13.
The schematic section in Figure 2 shows more in detail tails the auxiliary injection device of iet ~ of water from the Figure 1.
As can be seen in the drawing, the collector canceled re 17 consists of two parts 27 and 28 The annular part 27 rests on the body of the vacuum cleaner 1; the seal between the fixed part 27 and the wheel 2 is provided by a seal 29. By the way theirs, the upper part of the part 27 is usi ~ ee of ~ aniere ~ 2 ~ z to form a toothed wheel 30 axi ~ teeth, of which 1 ~ fi ~ ure 3 represents a developed view ~ which allows you to define support on the other part 28 a series of vertical channels 19 of passage of jets 16. As mentioned previously, ~ jets of pressurized water 16 make it possible to form, in space 15, a water screen li ~ allowing dlisolate the wheel 2 of the diffuser 3 and thus reduce the bubbling power Figure 4 shows an advantageous variant of the toothed wheel 30 of FIG. 2. According to this variant, the teeth defining the channels 19 are inclined relative to the ~ hori ~
zontal of an angle advantageously located around ~ a txen ~
taine of degrees, and in any case less than 90 degrees ~ way to direct the jets 16 in the direction tending to ~ turn the pump eg the wheel vanes 2. In this way, the jets 16 of the ention have, in addition to their function of creating a water screen, a function help to start the pump.
Figures 5 and 6 show a variant of the arrangement tif according to Figures 2 and 4, differentiating from these by the fact that the toothed wheel 30 is a frustoconical wheel, the ca-nals 19 then being not only inclined, as seen on FIG. 6, of about 30 degrees relative to the horizontal, but being further inclined by approximately the same value with respect to the vertical and to the left, i.e. towards wheel 2, the two angles of inclination being in any case less laughing ~ 90 degrees. The Applicant has found that this provision tion made it possible for the jets 16 to better assist the start-up pumping of the machine, while creating in space 15 a water screen as efficient as the one created by the configurations of toothed wheels 30 according to the figures ~ (2, 3) and (2, 4).
It goes without saying that the invention is not imitated achievements which have just been described ~ as an example. In particular, these realizations only have one device .

s6 ~ z 117, l9) injection of water jets upwards into the ace 15 place at the lower part of it ~ has qulon might as well place a device further or unique lie at the upper part of this space 15, then injecting jets 16 directed ~ downwards. However ~ such an availability ~
sition would pose additional congestion problems of so that the provision described above has been hole ~ ee ~
sufficient and sufficiently effective. We also for ~
provide all or part of the other floors with a disposit.i ~ of crea ~
tion of a curtain of water according to the invention, but their effectiveness would, however, be less than on the lower track due to decreasing the power of the jets 16 on the following stages ~ ~
in this case it would be desirable to add on each channel 20 an auxiliary pump allows both to increase the power of the jets 16.

Claims

The embodiments of the invention, concerning the-which an exclusive property or privilege is claimed, are defined as follows:

1. Multi-stage pump or turbine-pump with diffuser fixed and starting wet wheels, comprising:
- an auxiliary device placed at the lower floor, this lower floor comprising a wheel followed by a fixed diffuser, - means provided in this auxiliary device to create a large number of pressurized water jets creating a water screen in an annular space located between the wheel outlet and the diffuser, means for starting the pump either partial flow or zero flow.

2. Multi-stage pump or turbine-pump depending on the claim 1 comprising, in the direction of flow when the machine is operating as a pump:
- a water intake vacuum cleaner, - a first stage including a paddle wheel followed by a fixed diffuser, - a first return circuit used to bring water to a second floor, - a second stage comprising an impeller and a fixed diffuser, - a second return circuit allowing to bring water to the third floor, - a third stage including an impeller and a fixed diffuser, - an output circuit, comprising a pre-diffusion sister and a scroll, and - a forced discharge line fitted with a guard valve.

3. Pump or turbine-pump according to the claim tion 2, all of the above, with the exception of the vacuum cleaner and the volute which are asymmetrical, is of revolution around the machine shaft.

4. Pump or turbine-pump according to the claim tion 3, in which said water jets are injected bottom up and parallel to the machine shaft.

5. Pump or turbine-pump according to the claim tion 4, in which said auxiliary device comprises:
a water distributor ring, provided with a water inlet under pressure and drilled at its top a lot channels allowing the ejection of said water jets, a bypass line which brings the pressurized water to said entry connects by pipes said entry to the discharge pipe, i.e. upstream of the guard, either downstream of it, depending on whether taps spherical, placed on said pipes, are the first open and the second closed or the first closed and the second open.

6. Pump or turbine-pump according to the claim tion 5, wherein said water distributor ring comprises takes two pieces, one of the pieces leaning on the body of the vacuum cleaner and being fixed, a seal ensuring the watertight head between this fixed part and the wheel, this part fixed having an upper part which is machined so to form an input wheel defining by pressing on the be a part of said channels for the passage of water jets.

7. Pump or impeller-pump as claimed cation 1, wherein said auxiliary device is placed at the bottom of said annular space so as to inject said water jets upwards.

8. Pump or impeller-pump as claimed cation 1, wherein said auxiliary device is placed at the top of said annular space so as to inject said water jets downwards.

9. Pump or turbine-pump according to the claim tion 1, in which each stage is provided with such a device auxiliary positive.

10. Multi-stage pump or turbine-pump according to claim 1, characterized in that said arrangement auxiliary device is equipped with an injection device a large number of water jets.

11. Pump or impeller-pump as claimed cation 10, characterized in that said information device jection is equipped with vertically oriented channels.

12. Pump or impeller-pump as claimed cation 10, characterized in that said injection device tion is equipped with channels located in the vertical plane and inclined to the horizontal in the direction of rotation tion of the pump from an angle less than 90 degrees.

13. Pump or impeller-pump as claimed cation 12, characterized in that said angle of inclination naison is worth about 30 degrees.

14. Pump or impeller-pump as claimed cation 10, characterized in that said injection device tion is equipped with inclined channels on the one hand relative the vertical towards the wheel, and on the other hand by relative to the horizontal in the direction of rotation of the pump, angles less than 90 degrees.

15. Pump or turbine-pump according to the claim tion 14, characterized in that said angles of inclination both have a value of about thirty degrees.

16. Pump or impeller-pump as claimed cation 1, characterized in that said water curtain is created from a derivation from the conduct of delivery either upstream of the guard valve in the case starting the partial flow pump, either downstream of this in the case of starting at zero flow.