DK148848B

DK148848B - Self-priming centrifugal pump

Info

Publication number: DK148848B
Application number: DK260683A
Authority: DK
Inventors: Hans Kristensen
Original assignee: Svanehoej Pumpefabrik A S
Priority date: 1983-06-08
Filing date: 1983-06-08
Publication date: 1985-10-21
Also published as: DK148848C; DK260683D0; DK260683A

Description

1488A81488A8

Opfindelsen angår en selvansugende centrifugalpumpe med luftudskiller omfattende et kammer dannet af en skillevæg og den ene ende af pumpehuset, i hvilket kammer løbehjulet er anbragt, og hvori pumpens suge-5 ledning udmunder, og kammeret har to afgange, der er udformet således, at de tillader en rotation af en væskering langs pumpehusets periferivæg, og hvor pumpehuset i øvrigt fungerer som udluftningskammer og tilsluttet pumpens trykledning.The invention relates to a self-aspirating centrifugal pump with air separator comprising a chamber formed by a partition and one end of the pump housing, in which the chamber the impeller is arranged and in which the suction line of the pump opens and the chamber has two outlets which are designed so that they permits a rotation of a liquid ring along the peripheral wall of the pump housing and wherein the pump housing otherwise acts as a vent chamber and connected to the pump pressure line.

10 Pumper af denne type er kendt fra beskrivelsen til dansk patentansøgning nr. 857/67, de to britiske patentskrifter 536 627 og 559 086 samt tysk patentskrift 842 893. Ved disse kendte pumper indsættes der en kontraventil i sugeledningen for at forhindre, at 15 pumpehuset suges væsketomt, når pumpen standses.10 Pumps of this type are known from the specification for Danish patent application 857/67, the two British patents 536 627 and 559 086 and German patent 842 893. These known pumps insert a non-return valve in the suction line to prevent the pump housing fluid is sucked empty when the pump is stopped.

Skulle det alligevel ske, er det nødvendigt at opspæ-de pumpen op før start. Ved de kontraventiler, der benyttes, kan det ikke udelukkes, at de gror fast eller tilstoppes, så de ikke lukker helt tæt, hvorved 20 pumpehuset kan suges væsketomt. Formålet med opfindelsen er at angive en sådan konstruktion af pumpen, at risikoen for, at pumpehuset kan suges væsketomt reduceres betydeligt.Should this still happen, it is necessary to dilute the pump before starting. With the non-return valves used, it cannot be ruled out that they are stuck or clogged so that they do not close completely, so that the pump housing can be sucked fluid-empty. The object of the invention is to provide such a construction of the pump that the risk that the pump housing can be sucked fluidly is significantly reduced.

Pumpen ifølge opfindelsen er ejendommelig ved, at der 25 fra sugeledningen er ført en kanal ud til pumpehusets periferivæg i en afstand, så mundingen med sikkerhed er dækket af væskeringen ved pumpens opstart. Dette sikrer mod, at pumpen tømmes helt for vand. Ved opstart af pumpen dannes en væskering ved periferivæg-30 gen, som lukker for kanalen, således at der ikke kan slippe luft ind til løbehjulet og ødelægge selvansug- 148848 2 ningsevnen. Når pumpen stoppes, udlignes trykket i suge- og trykledningen, når vandstanden i pumpehuset falder til et niveau under kanalen. Konstruktionen har den fordel, at man i princippet kan undvære en 5 kontraventil i sugeledningen for at forhindre pumpen i at tømmes helt for væske.The pump according to the invention is characterized in that a channel is led out from the suction line to the peripheral wall of the pump housing, so that the mouth is safely covered by the liquid ring at the start of the pump. This ensures that the pump is completely drained of water. At the start of the pump, a liquid ring is formed at the peripheral wall, which closes the duct so that no air can enter the impeller and destroy self-sufficiency. When the pump is stopped, the pressure in the suction and pressure line is equalized as the water level in the pump housing falls to a level below the duct. The construction has the advantage that, in principle, one can avoid a check valve in the suction line to prevent the pump from being completely emptied of liquid.

I det følgende skal der med henvisning til tegningen beskrives et udførelseseksempel for opfindelsen.In the following, an embodiment of the invention will be described with reference to the drawing.

10 På tegningen viser: fig. 1 et aksialt snit gennem en udførelsesform for pumpen ifølge opfindelsen, og fig. 2 et vandret snit gennem pumpen.10 In the drawing: FIG. 1 is an axial section through an embodiment of the pump according to the invention; and FIG. 2 is a horizontal section through the pump.

15 Den på tegningen viste pumpe består af et i det væsentlige cirkulært pumpehus 1 med en overdel 2 og en fod 3 for fastmontering. Overdelen 2 har en tilslutningsstuds 4 for en trykledning og en anden tilslutningsstuds 5 for en sugeledning. Tilslutningsstudsen 20 5 for sugeledningen ender i pumpehuset 2 i en flange 6.The pump shown in the drawing consists of a substantially circular pump housing 1 with an upper part 2 and a foot 3 for fixed mounting. The upper part 2 has one connecting rod 4 for a pressure line and another connecting rod 5 for a suction pipe. The suction line connector 20 5 ends in the pump housing 2 in a flange 6.

I pumpehuset 2 er der et kammer 7, hvori pumpens løbehjul 8 er anbragt. Kammeret begrænses af pumpehu-. sets endevæg 9 og en skillevæg, der udgøres af ti 1 -25 slutningsstudsens flange 6 og en ring 10 uden om denne tætnet med en tætningsring 11. I kammeret 7 er der to porte 12,13.In the pump housing 2 there is a chamber 7 in which the impeller 8 of the pump is arranged. The chamber is limited by the pump housing. the end wall 9 of the set and a partition which is constituted by the flange 6 of the closing bracket 6 and a ring 10 around it sealed with a sealing ring 11. In the chamber 7 there are two gates 12,13.

3 168848 Løbehjulets aksel er placeret inden i sugeledningens tilslutningsstuds 5 og går gennem sidevæggen uden for pumpehuset, idet der i sidevæggen er anbragt et leje og en mekanisk akselpakning med oliebad 15, der er 5 fuldstændigt lufttæt.The shaft of the impeller is located within the suction line 5 of the suction pipe and passes through the side wall outside the pump housing, with a bearing and a mechanical shaft gasket with oil bath 15 which is 5 completely airtight.

Ved pumpehusets overside er en kanal 16, der fører fra tilslutningsstudsen 5, der er en del af sugeledningen, og ud til pumpehusets periferivæg.At the upper side of the pump housing is a conduit 16 leading from the connector nozzle 5, which is part of the suction line, out to the peripheral wall of the pump housing.

Når pumpen startes, suges der på grund af undertryk-10 ket ved omløbshjulets midte luft fra sugeledningen.When the pump is started, due to the suppression at the center air of the impeller, the suction line is sucked.

Kanalen 16, der over pumpehuset 1 står i forbindelse med trykledningen 4 og den atmosfæriske luft, lukkes hurtigt på grund af den væskering, der skabes i pumpehuset, således at der ikke ad den vej kan slippe 15 luft ind til omløbshjulet. Den luft, der suges fra sugeledningen, vil blandes med vandet i kammeret 7, og blandingen vil strømme ud gennem porten 13. På grund af den store trykgradient i pumpehuset vil den med væsken udslyngede luft søge ud gennem tryklednin-20 gen 4. Den ved pumpehusets periferi roterende væskering vil således i alt væsentligt være fri for luft.The duct 16, which communicates above the pump housing 1 with the pressure line 4 and the atmospheric air, is quickly closed due to the liquid ring created in the pump housing, so that 15 air will not be allowed to enter the circulation wheel. The air drawn from the suction line will be mixed with the water in the chamber 7 and the mixture will flow out through the port 13. Due to the large pressure gradient in the pump housing, the air discharged with the liquid will escape through the pressure line 4. the peripheral rotating liquid ring of the pump housing will thus be substantially free of air.

Fra væskeringen strømmer der hele tiden luftfri væske gennem porten 12 og ind i kammeret 7, hvor den blandes med den tilstrømmende luft fra sugeledningen og 25 strømmer ud gennem porten 13. Når sugeledningen er tømt for luft, virker begge portene 12,13 som afgange for den tilsugede væske.From the liquid ring, air-free liquid constantly flows through the port 12 and into the chamber 7, where it mixes with the flowing air from the suction line and 25 flows out through the port 13. When the suction line is emptied of air, both ports 12,13 act as outlets for the suction fluid.

Når pumpen standses dør væskeringen ud og undertrykket i sugeledningen 5 udlignes, idet kanalens 16 mun-30 ding frilægges, således at der suges luft ind fra 148848 4 trykledningen over pumpehuset. Dette sikrer, at der altid står væske tilbage i pumpehuset, når pumpen standses. I princippet kan man undvære den sædvanlige kontraventil i sugeledningen. At man alligevel ønsker 5 den i mange situationer, skyldes at den udøver en drøvlende virkning over for tilbageløbende væske, når pumpen standses, selvom kontraventilen ikke slutter fuldstændigt tæt.When the pump is stopped, the liquid ring dies out and the negative pressure in the suction line 5 is equalized, the mouth of the duct 16 being exposed, so that air is sucked in from the pressure line over the pump housing. This ensures that there is always liquid left in the pump housing when the pump is stopped. In principle, the usual non-return valve in the suction line can be dispensed with. The fact that it is nevertheless desired in many situations is because it exerts a drooling effect on the running fluid when the pump is stopped, even though the non-return valve does not close completely.

Anbringelsen af omløbshjulets aksel i sugeledningen 10 og lejet med tætning i sugeledningens væg uden for pumpehuset bevirker, at man kan få en fuldstændig akseltætning, og derved undgås problemet med indsugning af "falsk" luft ved akselgennemføringen.Placing the shaft of the orbital wheel in the suction line 10 and the bearing with a seal in the wall of the suction pipe outside the pump housing means that a complete shaft seal can be obtained, thereby avoiding the problem of sucking "false" air in the shaft passage.