Centrifugal pump for conveying a fluid

Abstract

A centrifugal pump for conveying a fluid includes a pump housing, an impeller to convey the fluid from an inlet to an outlet, a shaft to rotate the impeller, a first sealing device to seal the shaft at a suction side, a second sealing device to seal the shaft at a discharge side, a balance drum connected to the shaft between the impeller and the second sealing device, the balance drum defining a front side facing the at least one impeller and a back side facing the second sealing device, a relief passage between the balance drum and a stationary part, a balance line connecting the back side with the suction side, a discharge opening arranged at the relief passage between the front side and the back side, and a connecting line connecting the discharge opening with the first sealing device.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to European Patent Application No. 20169858.6, filed Apr. 16, 2020, the contents of which are hereby incorporated herein by reference in their entirety.BACKGROUNDField of the Invention[0002]The invention relates to a centrifugal pump for conveying a fluid.Background Information[0003]Conventional centrifugal pumps for conveying a fluid, for example a liquid such as water, are used in many different industries. Some examples are the oil and gas industry, the power generation industry, the chemical industry, the water industry or the pulp and paper industry. Centrifugal pumps generally have at least one impeller and a shaft for rotating the impeller. The at least one impeller can be configured for example as a radial impeller or as an axial or semi-axial impeller or as a helicoaxial impeller. Furthermore, the impeller can be configured as an open impeller or as a closed impeller, where a shroud is provided on ...

AI Technical Summary

Benefits of technology

The invention is a centrifugal pump for conveying fluids with high efficiency. It solves the problem of reducing the efficiency of the pump while ensuring the safety of the pump by reducing the additional flow of fluid needed for flushing and cooling of the sealing devices. The invention achieves this by using a connecting line that guides the flow away from the relief passage through a sealing device towards the inlet of the pump for flushing and cooling purposes, without the need for an additional take-off of pressurized fluid. This results in an increased efficiency of the pump as only the unavoidable leakage flow through the relief passage is used for flushing the sealing device. The connecting line can also include a flow control element to adjust the flow for flushing the sealing device. The invention also includes a third branch that can be connected to the suction side of the pump to route the flow back to the suction side without passing through one of the sealing devices. This helps to adjust the leakage flow through the relief passage.

Problems solved by technology

Of course, the leakage flow along the balance drum results in a decrease of the hydraulic performance or efficiency of the pump.

This required flow for flushing the sealing devices causes additional losses which reduces the efficiency of the pump.

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