Sponge Cleaning Balls – Types RS / RSL / RSR

Typical Applications

RS, RSL and RSR sponge cleaning balls are designed for use in online tube cleaning systems operating at temperatures up to 80°C, such as steam condensers and heat exchangers in conventional and nuclear power plants, as well as low-temperature MSF desalination plants.

Other sponge ball types are available for special operating conditions and specific applications.

Available Sizes

RS sponge cleaning balls are available in standard diameters ranging from 15 mm to 45 mm, in 1 mm increments.

The standard specification is medium hardness. Non-standard diameters and hardness grades are available upon request.

Material Composition

The balls are manufactured from a specially formulated natural rubber compound containing inert fillers.

The compound contains approximately 10–20% vulcanizing agents, and its composition has been carefully optimized to achieve the best balance between:

• Mechanical properties
• Service life
• Cleaning performance

The material is non-hazardous, and all ingredients used are approved for food-contact applications.

Colour Identification

Standard colours are:

• RS:Red
• RSL (Light Density):Yellow

Water Saturation and Settling Characteristics

Before use, each ball should be compressed three to four times under water to remove trapped air and ensure complete water saturation.

To ensure that every tube is effectively cleaned, the saturated ball should have a specific gravity close to that of the cooling water.

Typical settling velocities are:

• Standard Balls:8–12 cm/s
• Light-Density Balls (RSL):1–4 cm/s

Resistance to Cooling Water

RS sponge cleaning balls have been specifically developed for power plant condensers and similar industrial applications.

Although certain chemicals, such as petroleum products, hydrocarbons, or high concentrations of carbon-based contaminants, may adversely affect the ball material, these substances are rarely present in cooling water systems.

Consequently, RS sponge cleaning balls provide excellent resistance to virtually all types of cooling water.

Cleaning Performance

Sponge cleaning balls are designed to remove the soft deposits commonly encountered in once-through cooling water systems, including:

• Mud
• Silt
• Sand
• Slime
• Other soft fouling

They also help to reduce the formation of hard scale by removing the initial crystal nuclei from which deposits such as calcium carbonate develop.

Once hard scale has become established, however, sponge cleaning balls alone are generally no longer effective.

Within practical operating limits, cleaning performance is not significantly affected by either:

• Ball oversizing (the difference between the ball diameter and the tube inside diameter), or
• Ball hardness.

However, the ball diameter should always be slightly larger than the inside diameter of the tube to ensure effective cleaning.

The maximum permissible oversize depends on:

• The allowable pressure drop across the heat exchanger, and
• The need to prevent the ball from becoming lodged inside the tube.

Ball Service Life

The service life of sponge cleaning balls depends primarily on:

• Cleaning frequency
• Tube surface condition
• Operating conditions

Under normal operating conditions, the typical service life is approximately six weeks, although considerably longer service life may be achieved depending on site conditions and cleaning frequency.

Roughened, pitted or corroded tube surfaces significantly accelerate ball wear.

Where excessive wear is observed due to rough tube surfaces, the use of abrasive cleaning balls is recommended to restore a smooth tube surface before returning to standard sponge cleaning balls.

Note: Abrasive cleaning balls should be used with caution to avoid increasing the risk of corrosion, particularly in brackish water, seawater, or other cooling waters with high chloride concentrations. If there is any uncertainty regarding suitability, please contact us for technical advice.