Technical cover balls – tank cover for chemical and process baths
Open chemical and process baths pose a challenge in many industrial plants: valuable liquids evaporate, hazardous fumes are released, and heat is lost. Technical cover spheres offer an innovative solution. These are floating plastic spheres that drift on the liquid surface, covering the tank like a flexible lid. This method is successfully used in the chemical industry, in electroplating baths, and even in LNG terminals to prevent evaporation, save energy, and reduce emissions.
What are technical cover balls?
Technical cover spheres – also called hollow spheres or floating balls – are hollow plastic spheres that float on liquids and cover them by approximately 90%. Simply pouring a sufficient quantity of spheres creates a closed, floating layer that self-assembles to form a tight seal. The spheres are typically made of robust plastics such as polypropylene (PP), polyethylene (PE), or PTFE (Teflon).
Installation is incredibly simple: The spheres are installed maintenance-free by simply placing them on the liquid – they arrange themselves into a layer with minimal gaps. Unlike rigid covers, cover spheres dynamically adjust to the fill level: If the level drops, they stack in two layers; if the level rises, they spread evenly again. Even the immersion of workpieces or measuring probes is not hindered, as the layer of spheres immediately closes again. Furthermore, dangerous gas accumulations do not occur under rigid covers – a clear safety advantage.
Tank cover in the chemical industry
In the chemical industry, sphere covers are used as flexible tank covers for a wide variety of liquids. Wherever open basins or tanks containing chemicals are operated – for example, in acid baths, solvent tanks, or process tanks – these technical sphere covers help to reduce evaporation losses and contain emissions. Operators of chemical plants particularly appreciate that the sphere cover virtually eliminates harmful fumes and odors.
In addition, the spheres protect against contamination, as less dust or oxygen enters the liquid. The medium stays at its temperature longer because the spheres act as an insulating layer. In heated baths, heat loss can be reduced by up to 75%, enabling significant energy savings. This usually results in a short return on investment.
Evaporation protection in electroplating baths
Electroplating and anodizing baths benefit particularly from technical sealing spheres. Electroplating processes generate corrosive fumes and high temperatures, leading to significant evaporation. Floating sealing spheres reduce evaporation by over 85% and maintain a stable temperature. This translates to less chemical loss, lower energy consumption, and significantly improved workplace air quality.
The sphere cover also prevents splashes of aggressive liquids and reduces harmful aerosols such as chromic acid mist or hydrogen sulfide. Corrosion in the system is also reduced, as significantly fewer vapors reach the equipment and hall ceilings. Cover spheres are therefore a simple yet highly effective contribution to energy efficiency, environmental protection, and occupational safety.
Cover balls for LNG terminals
LNG terminals are a growing area of application. For cryogenic media such as liquefied natural gas (-162 °C), a sphere cover can reduce external heat input and thus slow boil-off. In containment tanks or water basins, cover spheres act as a thermal barrier and prevent excessive gas formation.
For such applications, special materials like PTFE are used because they withstand temperatures from -200 °C to +260 °C and are chemically almost inert. This allows technical cover spheres to contribute to increased safety and efficiency even in extreme environments.
Advantages of the cover balls at a glance
| Parameter | Without cover balls | With cover balls |
|---|---|---|
| Evaporation loss | 100% (unprotected) | up to 90% less |
| Heat/energy loss | 100% | up to 75% less heating requirement |
| Chemical emissions | unfiltered | up to 90% off |
| odor | strong | almost eliminated |
| Heating/operating costs | hoch | much lower |
| Work Safety | Risk from fumes/splashes | lower risk, no splashes |
In summary, technical cover balls offer the following advantages:
- Up to 90% less evaporation – less fluid loss and lower refill volumes.
- Up to 75 % Energieeinsparung through insulating air layer.
- Fewer pollutants and odors – clean air, less environmental pollution.
- More safety – no splashes, no gas accumulation, lower risk of explosion.
- Flexible & maintenance-free – automatically adjusts to the fill level.
- Fast payback – Energy and chemical savings quickly offset investment.
Material selection and chemical resistance
Polypropylene (PP)
PP balls are lightweight, robust, and cost-effective. They are resistant to many acids, alkalis, and salts and are suitable for temperatures up to approximately +100°C. Ideal for most electroplating and chemical baths.
polyethylene (PE)
PE is weatherproof and particularly suitable for outdoor applications, such as sewage treatment plants or water basins. It is chemically stable but only heat-resistant up to approximately +60°C.
Polytetrafluoroethylene (PTFE)
PTFE (Teflon) is the high-end version: extremely chemical-resistant and temperature-resistant from -200 °C to +260 °C. Ideal for aggressive media or extreme temperatures, such as in the semiconductor or LNG industries.
In special cases, materials such as PVDF are also used, which offer a compromise between temperature resistance and cost. However, in most cases, PP or PE are the most economical choice.
Technical cover spheres are a simple yet highly effective solution for protecting open tanks and process baths. They reduce evaporation, retain heat in the system, lower emissions, and improve safety. Whether in chemical production, electroplating operations, or LNG terminals – the floating sphere covers combine efficiency, sustainability, and safety.
With minimal effort, operators achieve maximum effect: simply cover tanks with plastic balls – and save energy, chemicals and costs in the long term.
Frequently Asked Questions (FAQ)
What are technical cover balls and how do they work?
Cover spheres float on liquids, forming a dense, flexible layer. This greatly reduces air exchange, significantly reducing evaporation, heat loss, and emissions. They automatically adjust to the water level and operate without mechanical installation.
Which materials are there?
Standard materials are polypropylene (PP) and polyethylene (PE). For extreme conditions, PTFE (Teflon) is used, which remains stable even at very high or very low temperatures.
How much of the surface is covered?
One layer of spheres covers approximately 90% of the surface. If necessary, two layers can achieve almost complete coverage.
Can cover balls be used in LNG terminals?
Yes, when using suitable materials such as PTFE. They reduce heat input and thus evaporation losses in open containment or containment tanks.
Do cover balls require maintenance?
No, high-quality balls are maintenance-free, UV-stable, and chemically resistant. Once installed, they remain functional for many years.
