DK144389B

DK144389B - CIRCULATORY PUMP IS AIR FOR HEATING AND USED WATER

Info

Publication number: DK144389B
Application number: DK122278A
Authority: DK
Inventors: P D Jensen
Original assignee: Grundfos As
Priority date: 1977-03-19
Filing date: 1978-03-17
Publication date: 1982-03-01
Also published as: FR2384138B3; DK122278A; FR2384138A1; DK144389C; DE2712155A1

Description

i 144389in 144389

Opfindelsen angår en cirkulationspumpe, især til opvarmnings- og brugsvandsanlæg, og hvor pumpehuset ved hjælp af en skillevæg er delt i et pumpekammer, som indeholder et løbehjul og et rotorkammer, som indeholder en rotor, 5 der indgår i en til pumpen hørende spalterørsmotor, og hvor pumpekammeret og rotorkammeret er forbundet med hinanden gennem lejespalten i et radialleje, hvilken skillevæg overskylles af den pumpede væske, f.eks. vand.BACKGROUND OF THE INVENTION The invention relates to a circulation pump, in particular for heating and domestic water systems, and wherein the pump housing is divided by means of a partition into a pump chamber which contains a impeller and a rotor chamber which contains a rotor which is included in a splice tube motor belonging to the pump, and wherein the pump chamber and the rotor chamber are connected to each other through the bearing slot in a radial bearing, which partition is flushed by the pumped liquid, e.g. water.

Sådanne pumpe anvendes først og fremmest til at fremkalde 1° tvungen cirkulation af vandet i opvarmningsanlæg samt brugsvandsanlæg. Skillevæggen hindrer passage frem og tilbage af vand mellem pumpekarameret og rotorkammeret, så at tilsmudsning af lejerne og dermed blokering af rotoren ungås. Skillevæggen sørger desuden for bortledning af størstede-len af den af motoren udviklede varme til det gennem pumpekammeret strømmende vand. Når varmebortledningen fra motoren er et problem, er det fordi, at kun ca. 20% af varmen i statorviklingerne (i spalterørsrummet) afgives direkte til omgivelserne. Resten af varmen må passere gennem motorens ΟΛ spalterør ind i rotorkammerets vand og derfra hen til skillevæggen, hvor den overføres til det gennem pumpekammeret pumpede vand.Such pumps are used primarily to induce 1 ° forced circulation of the water in heating systems as well as domestic water systems. The partition prevents the passage of water back and forth between the pump chamber and the rotor chamber, thus avoiding soiling of the bearings and thus blocking the rotor. In addition, the partition provides drainage of most of the heat generated by the engine to the water flowing through the pump chamber. When the heat dissipation from the engine is a problem, it is because only approx. 20% of the heat in the stator windings (in the gap pipe space) is delivered directly to the surroundings. The remainder of the heat must pass through the engine ter slit pipe into the water of the rotor chamber and thence to the partition wall where it is transferred to the water pumped through the pump chamber.

Vandtemperaturen i rotorkammeret vil til stadighed ligge over temperaturen af vandet, der passerer gennem pumpe- O c kammeret. Herved kan der opstå lejeproblemer, fordi der, hvis trykket i rotorkammerets vand falder til under en bestemt værdi, vil dannes dampblærer i vandet, så at man risikerer tørløb af lejerne, hvilket kan beskadige lejerne alvorligt. Der må også regnes med lejeproblemer, såfremt der i det vand, der skal pumpes gennem et opvarmningsanlæg, findes mange luftbobler. Disse vil nemlig i pumpekammeret blive trængt indad og samle sig ved pumpeakselens omkreds ved den ende af radiallejet, som vender mod pumpesiden, hvorved der er fare for, at dette leje løber tørt og efter en vis tid ødelægges.The water temperature in the rotor chamber will always be above the temperature of the water passing through the pump O chamber. This can cause bearing problems because if the pressure in the water of the rotor chamber falls below a certain value, vapor bubbles will form in the water, thus risking dry running of the bearings, which can seriously damage the bearings. Bearing problems must also be considered if there are many air bubbles in the water to be pumped through a heating system. Namely, these will penetrate into the pump chamber and collect at the periphery of the pump shaft at the end of the radial bearing facing the pump side, thereby causing the risk of this bearing running dry and being destroyed for some time.

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Pra USA patentskrift 3.067.690 kendes cirkulationspumper af spalterørstypen og med en skillevæg mellem pumpekammeret og spalterørsmotorens roterkammer, ved hvilke der til af-luftning af rotorkammeret og køling og smøring er tilveje-5 bragt en væskestrømning i rotorkammeret og forbi lejerne, idet der fra pumpens trykzone føres vand ind i rotorkammeret, -eventuelt gennem huller eller spalter i skillevæggen, og forbi lejerne og videre ind i pumpens sugerum. Selvom der er god køling og smøring, er der dog en vis fare for, at 10 den strømmende væske i rotorkammeret vil afsætte urenheder i lejerne.Pra United States Patent 3,067,690 discloses circulation pumps of the splice tube type and with a partition between the pump chamber and the rotor chamber rotor chamber, in which a flow of liquid is provided in the rotor chamber and past the bearings for venting of the rotor chamber and past the bearings. pressure zone, water is introduced into the rotor chamber, possibly through holes or gaps in the partition, and past the bearings and further into the suction room of the pump. Although there is good cooling and lubrication, however, there is some danger that the flowing fluid in the rotor chamber will deposit impurities in the bearings.

Endvidere er det fra tysk fremlæggelsesskrift 1.703.266 kendt at modvirke dannelsen af luftblærer omkring den roterende aksel i sådanne pumper ved at udforme en kanal i 15 akselen, hvorigennem luften kan afgå.Furthermore, from German Patent Specification 1,703,266 it is known to counteract the formation of air bubbles around the rotating shaft in such pumps by forming a duct in the shaft through which the air can discharge.

Endelig er det fra tysk offentliggørelsesskrift 2.529.399 kendt at udforme skillevæggen i sådanne pumper, således at de overskylles af det pumpede vand til forbedring af varmetransporten fra spalterørsrummet. Fælles for de kendte kon-20 struktioner er i øvrigt, at de er temmelig komplicerede.Finally, from German publication publication 2,529,399 it is known to design the partition in such pumps so that they are flushed by the pumped water to improve the heat transport from the slit pipe space. What is common to the known constructions is that they are rather complicated.

Formålet med opfindelsen er at anvise en cirkulationspumpe af den ovenfor nævnte art, som dels er meget simpelt udformet,dels hindrer tilsmudsning og tørløb af lejerne, og som desuden muliggør en meget effektiv varmeudveksling mellem 25 rotorkammeret og pumpekammeret gennem skillevæggen med hen blik på forbedring af varmetransporten fra spalterørsrummet.The object of the invention is to provide a circulation pump of the above-mentioned type, which is very simple in design and partly prevents soiling and dry running of the bearings, and which also enables a very efficient heat exchange between the rotor chamber and the pump chamber through the partition with a view to improving the heat transport from the slit pipe space.

Cirkulationspumpen ifølge opfindelsen er ejendommelig ved, at der findes mindst én kanal, der fører fra pumpens trykzone til radiallejets mod pumpesiden vendende ende. Herved 50 opnås foruden konstruktiv enkelhed en nedsat fare for tør løb, fordi det væsketryk,der opbygges ved pumpesiden af radiallejets spalte, vil være af samme størrelse som det, der findes i pumpens trykzone (og dermed altså svarende til summen af systemtrykket i anlægget og pumpetrykket), og dette 3 144389 tryk vil forplante sig ind i rotorkammeret, så at trykket her også bliver højt. Derved reduceres faren for uheldig dampdannelse i vidt omfang. Da der ikke er nogen væskestrømning gennem lejespalten, vil eventuelle luftblærer i 5 den pumpede væske ikke fremkalde tørløb af lejet. Endelig opnås en forbedret varmebortledning ved skillevæggen.The circulation pump according to the invention is characterized in that there is at least one duct leading from the pressure zone of the pump to the end of the radial bed facing the pump side. Hereby 50, in addition to constructive simplicity, a reduced risk of dry running is achieved, because the fluid pressure built up at the pump side of the radial bed slot will be the same size as that found in the pump pressure zone (and thus corresponding to the sum of the system pressure in the system and pump pressure) and this pressure will propagate into the rotor chamber so that the pressure here will also be high. This greatly reduces the risk of accidental vapor formation. Since there is no fluid flow through the bearing slot, any air bubbles in the pumped fluid will not cause dry running of the bearing. Finally, an improved heat dissipation at the partition is achieved.

Ifølge opfindelsen kan den eller de nævnte kanaler forløbe radialt og være afgrænset af. et ved siden af skillevæggen anbragt skiveformet ledeapparat, idet kanalens eller ka-nalernes yderste del, som danner indløbsåbningen,befinder sig i pumpens trykzone, medens kanalens eller kanalernes inderste del befinder sig ved et ringrum ved radiallejets lejespalte og strækker sig rundt om pumpeakselen og her via en slidsformet udløbsåbning kommunikerer med pumpe-15 kammeret. Derved opnås, at den væske, der strømmer gennem kanalen eller kanalerne, kan løbe tilbage til pumpekammeret, hvorved det modvirkes, at luftblærer kommer ind i lejespalten. Hertil kommer, at varmebortledningen via den pumpede væske øges, fordi det areal, via hvilket varmeover-20 gangen sker (nemlig via skillevæg + ledeapparat) øges.According to the invention, the said channel (s) may extend radially and be delimited by. a disc-shaped guiding device arranged next to the partition, the outer part of the duct or channels forming the inlet opening being in the pressure zone of the pump, while the inner part of the duct or ducts is at an annular space at the bearing gap of the radial bed and extends around the pump shaft and here communicates with the pump chamber via a slit-shaped outlet opening. This provides that the fluid flowing through the duct or ducts can flow back to the pump chamber, thereby preventing air bubbles from entering the bearing slot. In addition, the heat dissipation via the pumped fluid is increased because the area through which the heat transfer occurs (namely via partition + conductor) is increased.

Desuden kan ifølge opfindelsen tværsnittet af kanalens eller kanalernes indløbsåbning være større end tværsnittet af den eller disse kanalers udløbsåbning, hvorved opbygningen af et højt væsketryk ved lejespalten sikres.In addition, according to the invention, the cross-section of the inlet orifice of the duct or channels can be larger than the cross-section of the outlet orifice of the duct or channels, thereby ensuring the build-up of a high fluid pressure at the bearing gap.

25 Fremdeles kan ifølge opfindelsen ledeapparatet være rota tionssymmetrisk og have et centralt hul, hvis areal er større end tværsnitsarealet af pumpeakselen, hvilken sidste strækker sig gennem hullet, hvorhos udløbs åbningen for kanalen kan være bestemt af området mellem det cen-20 trale huls hulrand og pumpeakselens overflade. Derved fås en hensigtsmæssig afstrømning af væske fra kanalen til pumpekammeret.Still, according to the invention, the guide apparatus may be rotationally symmetrical and have a central hole, the area of which is greater than the cross-sectional area of the pump shaft, the latter extending through the hole, the outlet opening of the channel may be determined by the area between the central edge of the cavity and the pump shaft surface. This provides an appropriate flow of liquid from the duct to the pump chamber.

Endvidere er det ifølge opfindelsen hensigtsmæssigt, at yderdiameteren af ledeapparatet er 0,5-1,8 gange yder- 4 144389 diameteren af løbehjulet.Further, according to the invention, it is convenient that the outer diameter of the guide is 0.5-1.8 times the outer diameter of the impeller.

Ifølge opfindelsen kan ledeapparatet og skillevæggen mest hensigtsmæssigt være føjet sammen til en enhed ved hjælp af svejsning.According to the invention, the guide device and the partition can most conveniently be joined to a unit by welding.

5 Endelig kan der ifølge opfindelsen på skillevæggen eller ledeapparatet være tilvejebragt fremspring, som fastlægger afstanden mellem disse dele og dermed bredden af kanalen, hvorhos de steder, hvor skillevæggen og ledeapparatet er føjet sammen, findes ved de nævnte fremspring. Derved op-1Q nås yderst simpel konstruktion.Finally, according to the invention, projections may be provided on the partition or guiding device which determine the distance between these parts and thus the width of the channel where the places where the partition and the guiding device are joined are found at said projections. This results in very simple construction.

Opfindelsen forklares nedenfor under henvisning til tegningen, som viser en udførelsesform for centrifugalpumpen ifølge opfindelsen set fra siden delvis i snit.The invention is explained below with reference to the drawing, which shows a side view of the centrifugal pump according to the invention in partial section.

Den viste pumpe har et hus 1, som ved hjælp af en skille-15 væg 3, der rager i hovedsagen radialt ud fra huset l's længdeakse 2, er delt i et pumpekammer 4 og et rotorkammer 5, Pumpekammeret indeholder et løbehjul 8,medens kammeret 5 indeholder en rotor hørende til pumpens elektromotor. Elektromotorens aksel 6 - pumpeakselen - som 2Q bærer løbehjulet, er ført gennem skillevæggen 3, idet den er lejret i et radial-aksialleje 7 heri. Radiallejedelen 7' i dette leje er anbragt i en i skillevæggen 3 udformet skål, medens lejets indre ring 7” er fast forbundet med akselen 6. Mellem radiallejedelen 7’ og akselen 6 findes 25 en lejespalte 7a.The pump shown has a housing 1 which is divided into a pump chamber 4 and a rotor chamber 5 by means of a partition wall 3 extending radially out of the longitudinal axis 2 of the housing 1, the pump chamber contains a impeller 8, while the chamber 5 contains a rotor for the electric motor of the pump. The shaft 6 of the electric motor - the pump shaft - which 2Q carries the impeller is passed through the partition 3, being housed in a radial-axial bearing 7 therein. The radial bearing part 7 'of this bearing is arranged in a bowl formed in the partition 3, while the inner ring 7' of the bearing is fixedly connected to the shaft 6. Between the radial bearing part 7 'and the shaft 6 there is a bearing slot 7a.

Pumpen har et sugerum 9 og en trykzone 10. De indføjede pile viser vandets strømningsfaaner.The pump has a suction chamber 9 and a pressure zone 10. The inserted arrows show the flow taps of the water.

På den ene side af skillevæggen 3 er der monteret et ledeapparat 11, som fastlægger en i hovedsagen radialt indad- 30. forløbende kanal 12, Denne kanal forløber fra pumpens trykzone 10 til pumpesiden af radiallejet 7r, 7a.On one side of the partition 3 is mounted a guiding device 11 which defines a substantially radially inwardly extending channel 12. This channel extends from the pressure zone 10 of the pump to the pump side of the radial bearing 7r, 7a.

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Den radialt betragtet inderste ende af kanalen befinder sig i området for lejespalten 7a og danner et ringformet rum 12' rundt om pumpeakselen 6. Her har kanalen en udløbsåbning i form af en ringspalte 12b, som indmunder i pumpe-5 kammeret nær løbehjulets 8 nav.The radially viewed inner end of the channel is in the region of the bearing slot 7a and forms an annular space 12 'around the pump shaft 6. Here, the channel has an outlet opening in the form of a ring slot 12b which opens into the pumping chamber near the hub of the impeller 8.

Ledeapparatet 11 kan som vist have form som en rotationssymmetrisk skive, som er forsynet med et centralt hul, så at den nævnte udløbsåbning 12b fastlægges af det område, som befinder sig mellem hulranden og den overfor liggende 10 akseloverflade.As shown, the guiding device 11 may take the form of a rotationally symmetrical disc provided with a central hole, so that said outlet opening 12b is defined by the area located between the hole edge and the opposite shaft surface.

Trykket i trykzonen 10 svarer til summen af systemtrykket i anlaagget og det af løbehjulet 8 frembragte pumpetryk.The pressure in the pressure zone 10 corresponds to the sum of the system pressure in the system and the pump pressure produced by the impeller 8.

Dette tryk overføres gennem åbningen 12a og kanalen 12 til lejespalten 7a og ledes derfra ind i rotorkammeret 5, der 15 således i sammenligning med hidtil kendte pumper af denne art bliver undergivet et forholdsvis højt tryk. Derved udelukkes dampbobbeldannelse og de dermed følgende ulemper i rotorkammeret 5.This pressure is transmitted through the opening 12a and the duct 12 to the bearing slot 7a and is thereafter fed into the rotor chamber 5, which, in comparison with previously known pumps of this kind, is subjected to a relatively high pressure. This eliminates steam bubble formation and the resulting disadvantages in the rotor chamber 5.

Tyærsnittet af udløbsåbningen 12a er fortrinsvis større 20 end tværsnittet af udløbsåbningen 12b.The cross-section of the outlet opening 12a is preferably larger than the cross-section of the outlet opening 12b.

Det er bedst, såfremt ledeapparatets 11 yderdiameter er 0,5-1,8 gange løbehjulets 8 yderdiameter.It is best if the outer diameter of the guide 11 is 0.5-1.8 times the outer diameter of the impeller 8.

Hvis den væske, f,eks. vand, der skal pumpes, indeholder luftblærer, vil disse samle sig i løbehjulsrummets cen-25 trale del, altså først og fremmest ved akselens overflade mellem løbehjulet 8 og ledeapparatet 11. Den stadige væskestrøm gennem udløbsåbningen 12b i retning af løbehjulet 8 forhindrer dog, at luftblærerne kan nå ind til lejespalten 7a gennem åbningen 12b og fremkalde tørløb af lejet.If the liquid, e.g. water to be pumped contains air bladders, these will collect in the central part of the impeller space, that is, first and foremost at the shaft surface between the impeller 8 and the guiding device 11. However, the constant flow of liquid through the outlet opening 12b in the direction of the impeller 8 prevents the air bladders can reach the bearing slot 7a through the opening 12b and induce dry running of the bearing.

20 Det v;q afhænge af valget af tværsnitsforholdet mellem indløbsåbningen 12a og udløbsåbningen 12b, hvor meget vand der vil strømme hen over skillevæggen 3. Ved passende valgIt depends on the choice of the cross-sectional relationship between the inlet opening 12a and the outlet opening 12b, how much water will flow over the partition 3. If appropriate,

Claims

144389 of the cross-sectional ratio, an optimum heat exchange between the rotor chamber 5 and the pump chamber 4 can be obtained via the partition, depending on the operating conditions and structural features concerned.

5 To facilitate manufacture and assembly of the guide 11 and the partition wall 3, these are preferably of pressed steel plate. The parts are assembled by welding. On the partition or guiding device there may be formed projections 13 which determine the distance between these parts and thus the width 10 of the channel 12. At these projections there are the welds between the partition and the guiding apparatus. Instead of a single duct with a circumferential inlet opening 12a, several ducts with separate inlet openings may be provided, which last into the pressure zone 10. These ducts then run at the pump side of the radial bed into a single annular space so that there are symmetrical flow conditions in bearing slot 7a and in annulus 12 'plus outlet opening 12b (axis of symmetry is pump axis 2). A circulation pump, especially for heating and domestic water systems, and wherein the pump housing (1) is divided by means of a partition (3) into a pump chamber (4) containing a impeller (8) and a rotor chamber (5), which includes a rotor which is part of a splice tube motor belonging to the pump and wherein the pump chamber (4) and the rotor chamber (5) are connected to each other through the bearing slot (7a) in a radial bearing (7r), which partition is flushed by the pumped liquid, eg. water, characterized in that there is at least one duct leading from the pressure zone (10) of the pump to the radial bed (7 ', 7a) facing the pump side.

Pump according to claim 1, characterized in that it