Self-adjusting liner for centrifugal pump

Abstract

A self-adjusting liner assembly for installation within a centrifugal pump of the type having an impeller and a pump casing having a suction inlet is provided, comprising a liner having a sealing end, the sealing end having at least one substantially planar outer most surface for contacting an outer surface of the impeller; and a resilient member disposed in the liner, said resilient member providing a force so that the at least one outer most surface remains in substantially continuous contact with the outer surface of the impeller.

Description

FIELD OF THE INVENTION[0001]The present invention relates to centrifugal pumps in general and more specifically to a self-adjusting liner assembly for centrifugal pumps for substantially reducing recirculation damage to the impeller.BACKGROUND OF THE INVENTION[0002]Centrifugal pumps are commonly used to move mixtures of solids and liquids through piping. The mixture enters the pump impeller along or near the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute (casing) which surrounds the impeller from where it exits into the downstream piping.[0003]Most centrifugal pumps which handle mineral slurries, for example, oil sand slurries, run into problems with respect to solid particles of the slurry becoming trapped between the rotating impeller and the surrounding volute during operation, thereby causing wear and abrasion of both the impeller and the volute. This results in downtimes for repair and ultimately reduces the life of the pump...

AI Technical Summary

Benefits of technology

The present invention is about a self-adjusting liner assembly for centrifugal pumps. It includes a liner and a resilient member that provides a force to keep the liner in continuous contact with the outer surface of the impeller. The liner has a sealing end with a wear ring or a recessed portion for housing the resilient member. The technical effect of the invention is to improve the performance and efficiency of centrifugal pumps by reducing friction, wear, and pump vibration, resulting in a smoother and more steady operation.

Problems solved by technology

Most centrifugal pumps which handle mineral slurries, for example, oil sand slurries, run into problems with respect to solid particles of the slurry becoming trapped between the rotating impeller and the surrounding volute during operation, thereby causing wear and abrasion of both the impeller and the volute.

This results in downtimes for repair and ultimately reduces the life of the pump and its hydraulic efficiency.

The problem tends to be more serious on the suction side of the impeller, where the high pressure liquid inside the discharge portion of the volute tends to flow towards the low pressure zone in the suction portion of the pump.

This is commonly referred to as suction-side recirculation, which results in a loss of pump hydraulic performance and efficiency.

In particular, increase in suction-side recirculation may directly contribute to loss of efficiency.

Furthermore, as wear increases, the gap between the impeller and the volute becomes larger if unaddressed and a higher rate of flow can pass through the gap, speeding the deterioration process.

However, these suction liners still create a gap where solids can cause abrasion damage.

Also, it is somewhat unpredictable as to when the suction liner will need to be replaced, which may result in unexpected pump failures.

However, one will still have to rely on human intervention to adjust the wear ring according to a schedule or a particular criterion.

Furthermore, in between these adjustments, wear will occur, allowing a continuing increase in recirculation.

Therefore, the seal cannot be independently adjusted.

While the design in U.S. Pat. No. 7,189,054 has this feature, the driving force to create the adjustment is limited by the use of balanced hydraulic forces to locate the adjustable component.

If, as seems likely, solid material were to accumulate in the gaps on either side of the adjustable component, the hydraulic force required to advance towards the impeller may not be sufficient to overcome the friction due to solids accumulation; the adjustment mechanism seems vulnerable to loss of function.

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