DE866140C - Vertical centrifugal pump especially for aggressive liquids - Google Patents

Description

The present invention relates to vertical centrifugal pumps with a riser pipe arranged concentrically around the shaft, which do not have a non-return valve, so that the liquid in the pressure and suction lines can freely flow back into the sanitary container when the pump is stopped.

With the pumps known so far. - This is how the .wave gap Sealed between the shaft and the riser pipe with gland packing. The application from the. Stuffing box packings when pumping aggressive liquids, such as alkalis and serums do not provide a perfect or permanently effective seal. .

In other known designs, within the Sbeigrahnes is around ! the shaft is also placed in a protective tube, which means that: the shaft spacing is essential prolonged and the escape of liquid is inhibited, but not prevented, that liquid can leak out. It is also known to prevent the access of the delivery liquid to the shaft gap during the conveyance by means of impeller rear side piling impede.

The present invention is essentially based on the combination -this both; known features, d. H. that around the shaft within the Riser pipe a second fixed pipe is arranged arid between this pipe and the shaft gap formed at the same time by one hydraulically acting Shaft gap sealing, e.g. B. an auxiliary conveyor is sealed.

Fig. I shows no embodiments of the invention. Inside the Sbeigrohnes; a, a second tube b is fixedly arranged around the shaft, which engages with its lower end in.; The inlet of the auxiliary conveyor wheel e arranged on the rear side of the conveyor wheel. When the pump is in operation, the gap liquid passing through the annular gap d is conveyed back into the pressure chamber of the pump by the auxiliary feed wheel c, which prevents the conveyed liquid from rising between the shaft and the pipe b and outwards. can emerge. This embodiment is otherwise required for such pumps waste is IThe seal avoided by Sbopfbuchspaekungen.

Fig.2 shows another embodiment of the invention. Here is the splitting fluid is not fed back into the pressure chamber of the pump, but through Channels ie, which are passed through the pressure housing and the gap liquid returns to the suction hanger. In the illustrated embodiment are for Support, the return of the fission liquid open blades / on the back of the impeller arranged. This version has the advantage that when it comes to a standstill the pump, the liquid flowing back from the pressure line through the channels e can flow back unhindered into the suction container. This is especially then of Advantage if there are long pressure lines and correspondingly larger quantities Liquid flows back when the pump stops.

Claims (3)

PATENT CLAIMS: i. Vertical centrifugal pump especially for aggressive Liquids with a riser pipe arranged concentrically around the shaft, characterized in that that around the shaft within the riser pipe (a) in a known manner a second fixed Tube (b) is arranged and that the one formed between this tube and: the shaft Shaft gap due to its well-known hydraulically acting shaft split seal, z. B. an auxiliary conveyor wheel (c) is sealed. 2. Vertical centrifugal pump according to claim i, characterized in that for recirculation, the cracking liquid through the pressure housing , continuous channels leading to the suction container (ie) are arranged. 3. Vertical centrifugal pump according to claim 2, characterized in that to support the return of the gap liquid on the back of the auxiliary conveyor blades (f) are arranged. Cited publications: C. P f 1 ie iderer "Die Kreisielpump, en", 1: 932, Fig. 284a; Swiss Patent No. 23-9815-