Revised Web Page - 2017 July 14

SSC Stub shafts

RULA design, manufacture and supply stub shafts for SSC conveyors for a wide range of Bulk Materials handling applications


The purpose of the RULA SSC conveyor stub shafts is to have a durable, strong and leak resistant stub shaft where you cannot fit a solid shaft The RULA stub shaft design utilise a primary sealing layout that is very successfully used in slurry pumps. The primary seal, which follows the basic layout of a mechanical seal, consists of two stainless steel rings, one rotating and the second stationary. Each of the two rings has a face which has been hard faced using a special ceramic coating. These two faces are pressurised against each other in order to achieve the primary sealing interface. The ceramic coating on the faces ensure extended life of the seal before refurbishment will be required. The faces are also lapped to one light band flatness to ensure that a seal is achieved as soon as the stub shaft is put in operation. The layout allows for the seal to absorb any deflection of the shaft due to the fact that the sealing face is perpendicular to the axis of rotation as opposed to the traditional parallel arrangement. Mechanical springs located behind the stationary seal ring also allows for tilting of the seal rings which will occur as the shaft deflects. The springs also serve to provide adequate pressure between the faces to ensure sealing. As a secondary seal, three gland packing rings will be installed behind the mechanical seal. These can be tightened or replaced while the stub shaft is in operation and does not require the unit to be removed from service. As an additional sealing interface, sealing water can also be installed. The sealing water, provided at a higher pressure than the water in the main trough, will serve to flush the mechanical seal interface should any ash enter the primary seal. The whole sealing assembly can be removed as a unit to allow for refurbishment or replacement should it be required. A second flange interface has been added to provide easier access to both the seal assembly as well as the bearings should maintenance or replacement of them be required. The bearings have also been provided with the necessary grease passages through which regular greasing is required.

Design features

- The stub shaft can be installed onto any current interface without requiring minor changes to the ashbox.

- The sealing interface consist of three levels of sealing.

- The primary seal, utilising a mechanical layout, allows for deflection in the shaft without compromising the sealing interface.

- The secondary seals can be maintained while the stub shaft is in operation.

- Access is provided to the bearings in order to maintain or replace them should it be required

Material of construction specifications

- Body: SANS 50025 Grade S 355 JR

- Shaft: EN8

- Seal: Various components - Nitrile rubber, s/s 304, nylon, Klinker gasket


- Stub shafts are purpose made in any size and shape to fit plant requirements

- Drilling arrangement to suit plant interface

Operating & Maintenance

The stub shafts are Operator and Maintenance friendly

A complete Operating & Maintenance manual is available

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