Distributor supplies new valve range

14th May 2021 By: Halima Frost - Reporter

Distributor supplies new valve range

FLOOD GATE The Clarkson slurry knife gate valve range is being offered to the South African market by uNyasi Sales and Services

Valve and actuator supplier uNyazi Sales and Services, a technical partner of engineering, procurement and construction company Lesedi Nuclear Services, is an official distributor of the Clarkson slurry knife gate valve.

uNyazi is the authorised Emerson Local Business Partner for final control products of well trusted known brands, including but not limited to industrial valve and actuator manufacturers Anderson Greenwood, Bettis, Crosby, Clarkson and Fisher.

Clarkson high performance slurry isolation and control valves have led the industry in elastomeric sleeve technology for 50 years.

The comprehensive line of slurry knife gate valves leads the market in the mining, mineral processing, and general process industries.

Valves come standard as self-purging bidirectional shut-off, ensuring repeatable positive isolation in critical applications.

The valves, although best suited to mining slurry applications, are equally effective in pulp and paper, coal preparation and steel applications.

“Your energy suppliers produce coal ash and slurry that needs to be removed effectively to maintain efficacy at the power station,” valves and automation executive Stephen David tells Engineering News.

He points out that the valves have been designed to handle such erosive and corrosive media, especially when using sea water as the carrying medium in the system.

An uNyazi mining operations client, using sea water in its slurry removal process, is a regular buyer of the Clarkson knife gate valve.

“You have the attack of the erosive slurry, as well as the corrosive sea water, so the elastomer or polymer on the liner must be robust,” adds David.


The valves ensure a tight shut off by deploying a patented gate edge seal that creates a continuous seal around the gate, together with a precision-moulded elastomer seat to deliver zero leakage.

This heavy duty, replaceable seat increases the contact area and resilient sealing ability of the valve compared to standard O-ring designs, resulting in superior isolation performance over an extended lifecycle.

The valves improve throughput allowing the client to run its processes for longer with a valve design optimized to thrive in heavy slurry conditions. A full round port eliminates protrusions into the flow, minimizing turbulence across the valve to extend body life.

“This not only ensures the longevity of sealing components, but also minimizes the damaging impacts of slurry on downstream pipeline equipment,” he explains.

The valves minimise wear, therefore, extending the life of the valves with standard inlet and outlet hardened wear rings to protect the sealing elements and body from abrasive slurry.

These durable Ni-Resist rings can be rotated three times through four positions to extend valve life and replacement intervals, allowing the client to improve its asset use and process productivity.

The valves minimize valve repair downtime by simplifying maintenance, with external packing adjustments that dynamically self-adjust compression in the gate edge seal system.

Repairs can be performed effectively using standard tools and readily available spare parts. The valve is also designed to Manufacturers Standardization Society -single plate-135 face-to-face dimensions for simple changeout and upgrade of the clients’ underperforming installed valves.

Further advantages of the valves include reduced project risk, and user and management support, as well as faster implementation and reduced attrition.

David stresses that downtime in mining and industrial operations costs producers money, and while scheduled maintenance does come at a cost, it is an absolute necessity.

“It is when production halts for equipment failure that the costs really start to bite,” he concludes.