Controlling slurry flow presents challenges that conventional control valves are not always designed to handle. Abrasive particles, suspended solids and changing process conditions can affect valve performance, making accurate flow regulation essential.

At KV Controls, we understand that selecting a segmented ball valve for slurry control involves more than abrasion resistance. The valve must provide consistent throttling, accurate positioning and reliable operation under demanding process conditions.

Our RV Series segmented ball valve combines the control capabilities of a V-notch opening with efficient quarter-turn rotary operation. Its design makes it particularly relevant to slurry applications in mining, mineral processing, pulp and paper, and other industrial processes.

How Segmented Ball Valves Improve Slurry Flow Control

Unlike conventional ball valves primarily designed for isolation, segmented ball valves are engineered for modulating control.

The RV Series incorporates a precisely contoured V-notch segmented ball that regulates the effective flow area as the valve rotates.

This allows the valve to respond progressively to changing process requirements rather than operating only in fully open or closed positions.

V-Notch Technology and Precise Throttling

One of the most important control features of the RV Series is its equal-percentage inherent flow characteristic.

This means that equal increments of valve travel produce approximately equal percentage changes in flow capacity under constant differential-pressure conditions.

At smaller openings, the V-notch allows relatively fine adjustments in flow capacity. As the valve opens further, progressively greater flow capacity becomes available.

For slurry applications, this characteristic can provide useful control across varying operating conditions.

However, actual installed performance depends on correct valve sizing, differential pressure and the hydraulic characteristics of the system.

Accurate Positioning and Reduced Hysteresis

Precise valve positioning is essential when controlling slurry flow continuously.

The RV Series incorporates a splined connection between the shaft and segmented ball, designed to support accurate positioning and low hysteresis.

Hysteresis occurs when a valve responds differently depending on whether it approaches a position from the opening or closing direction.

Excessive hysteresis can affect control stability and cause unnecessary actuator movement.

The RV Series shaft connection helps minimise unwanted mechanical movement, supporting consistent throttling performance.

Shearing Action: A Key Advantage in Slurry Applications

One of the distinguishing features of a segmented ball valve is the shearing action between the rotating ball segment and the valve seat.

As the valve closes, the edge of the segmented ball moves across the seating area, helping displace certain suspended solids and cut through fibrous materials.

This action can reduce the likelihood of material accumulating around the seat and interfering with valve movement.

For slurry applications, maintaining consistent movement is important because solids accumulation can affect positioning and shutoff performance.

The RV Series is designed with this shearing action to support smoother operation in suitable slurry and fibre-containing applications.

However, the effectiveness of this feature depends on particle size, hardness and slurry composition. Hard abrasive particles still require careful consideration during valve selection.

Metal-Seated Construction for Abrasive Slurry

Seat selection plays an important role in slurry control valve performance.

The RV Series offers metal-seated configurations designed for demanding applications, including certain slurry services.

Its spring-loaded seating arrangement is designed to maintain contact between the seat and segmented ball, supporting sealing performance.

Metal seating may be appropriate where abrasive particles or elevated temperatures make softer seating materials unsuitable.

However, metal seating does not eliminate wear.

At KV Controls, we consider slurry abrasiveness, operating temperature, differential pressure and shutoff requirements when evaluating the appropriate seat construction.

Why Valve Sizing Matters in Slurry Control

Correct valve sizing is essential for both control performance and managing abrasive wear.

When slurry passes through a partially open valve, local flow velocities increase around the throttling restriction.

If the slurry contains abrasive particles, these higher velocities can accelerate erosion of the valve’s internal components.

An oversized valve may operate continuously near the closed position, concentrating flow through a small opening.

An undersized valve may not provide sufficient capacity during maximum process demand.

For this reason, we evaluate minimum, normal and maximum flow conditions rather than selecting a valve based only on pipeline diameter.

Differential pressure is equally important. Higher pressure drops can increase local velocities and wear, making it necessary to assess the actual operating conditions against the valve’s capabilities.

Segmented Ball Valves in Mining and Mineral Processing

Mining and mineral processing applications frequently involve liquids containing suspended mineral particles.

These slurries can vary significantly in concentration, abrasiveness and flow requirements.

Segmented ball valves can be considered for suitable applications requiring continuous flow regulation.

The RV Series offers several relevant design features:

• V-notch segmented ball: Provides characterised throttling control.
• Quarter-turn operation: Supports continuous modulating control.
• Splined shaft connection: Promotes accurate positioning and low hysteresis.
• Shearing action: Helps reduce interference from certain solids and fibres.
• Metal-seated options: Provide seating alternatives for demanding operating conditions.
• Replaceable seat construction: Supports inspection and maintenance of internal components.

These features make the RV Series a practical option to evaluate for slurry control, although suitability must always be confirmed against the specific process conditions.

Selecting the Right Slurry Control Valve

At KV Controls, we consider several important factors when evaluating a segmented ball valve for slurry applications.

These include slurry composition, particle size, solids concentration, flow requirements, differential pressure, operating temperature and the required control performance.

Actuator selection is also important because the valve must respond accurately to control signals while providing sufficient operating torque.

By evaluating these factors together, we can determine whether the RV Series is appropriate for the application and identify a suitable configuration.

Frequently Asked Questions

Are segmented ball valves suitable for abrasive slurry?

Yes, segmented ball valves can be suitable for certain abrasive slurry applications. However, the valve materials, seating arrangement, particle characteristics and operating differential pressure must be carefully evaluated.

What makes a segmented ball valve effective for slurry control?

The V-notch provides characterised throttling, while the rotary design enables modulating control. Shearing action and available metal-seated construction also support operation with certain suspended solids.

Why is a V-notch important for slurry flow control?

The V-notch progressively changes the flow area as the valve rotates, allowing the control system to regulate flow over a range of operating positions.

Reliable Slurry Control Starts With Correct Valve Selection

Effective slurry control requires a valve that provides accurate throttling while accommodating the challenges of suspended solids and abrasive media.

Our RV Series segmented ball valve combines V-notch flow control, rotary operation, shearing action and available metal-seated construction in a design intended for modulating service.

At KV Controls, we focus on matching the valve to the process conditions to achieve the required control performance and support long-term maintainability.

Need a Segmented Ball Valve for Slurry Control?

Our team can assist with evaluating the RV Series for your slurry application.

Contact us with your slurry characteristics, operating pressures, flow requirements and control specifications.

KV Controls – Control & Isolation Valves
Email: sales@kvcontrols.co.za
Website: www.kvcontrols.co.za
Location: Sasolburg, South Africa