Tank cover in the chemical industry: Insulation & emissions reduction (case study)
Why open pools are expensive
Open process tanks continuously lose energy and medium through their exposed surface. This increases heating and replenishment costs, promotes aerosols/vapors, and pollutes the indoor air. Technical cover spheres (floating hollow plastic spheres) form a self-sealing layer on the surface and reduce the "effective" area – with measurable effects on evaporation, heat loss, and emissions.
What are cover balls – and how do they work?
Cover spheres made of PP, HDPE, or PVDF float as a loose layer on the medium. Due to their hexagonal, tightly packed structure, they cover approximately 90-91% of the surface (single layer); at higher fill levels, the cover automatically closes. The result: significantly less convection, evaporation, and splashing/aerosol formation.
Use in chemistry & electroplating
- Evaporation protection: significantly less medium loss and refill requirements.
- Energy saving: Lower heat loss through the surface – more stable bath temperature, faster reheating after downtime.
- Emissions/Aerosols: Reduced fumes, mists and splashes → better air quality, less separation and extraction required.
- Process stability: fewer temperature drops, more homogeneous bath.
- Safety & Hygiene: less contact, less smell, less corrosion in the environment.
Choice of materials & durability
- PP (polypropylene): Cost-effective, up to approximately 100 °C; good chemical resistance in many applications.
- HDPE: Robust, UV-stable; for water/wastewater, cooling/rainwater, and process water.
- PVDF: High-performance material for aggressive media (e.g. strong acids, solvents) and higher temperatures.
Practical rule: Choose material according to medium (pH, oxidizing agent), temperature and fire protection; diameter usually 20-50 mm for industrial tanks.
Dimensioning in 5 steps
- Pool area (m²) determine.
- Coverage level:
- Standard: ≈ 91% (single layer).
- In case of heavy emissions, larger diameter (= more stable top layer).
- ball count: depends on Ø and pool area (use supplier tables).
- Material: PP/HDPE/PVDF depending on medium & temperature.
- Periphery: Take into account internals, agitators, product carriers (free stroke, skimming).
💡 Case study (anonymized)
Background: Pickling/rinsing basin, 10 m² Surface, 60 ° C, Airflow with edge extraction. High evaporation, heavy fog formation, noticeable heat loss during downtime.
Measure: Mounting PP cover balls Ø 25 mm, single layer.
Result (12 months):
- Evaporation: significantly reduced (≈ 85-90% less surface losses).
- heat loss: noticeably lower (decrease of ≈ 70-75% depending on the operating status).
- Emissions: less mist/aerosols; extraction power could be reduced.
- Economic efficiency (simplified example calculation):
- Before: 10 m² * 1,2 kWh/(m²·h) surface loss * 16 h/day * 250 days ≈ 48 kWh/a.
- After (-70%): ≈ 14 kWh saved/a. At 0,12 €/kWh ≈ 1 €/a Savings – plus lower chemical consumption & refilling.
Note: Values vary depending on the medium, temperature, airflow, and cover; the calculation serves as a model for guidance.
Integration into the ventilation strategy
Cover spheres reduce the required extraction capacity . Often, a lower flow rate at the basin rim is sufficient; this reduces the energy consumption and maintenance requirements of the exhaust air purification system. Always check the risk assessment and permitting status before retrofitting.
Assembly & Operation
- Installation: Pour balls, use the distributor; when the fill level is lowered/raised, the lid closes/opens automatically.
- Maintenance: Regularly check visually, clean if necessary, replace defective balls.
- Peripherals: Consider the movement of goods in the electroplating/pickling process; if necessary, provide ball catchers/barriers in front of gutters/overflows.
Risks & Limitations
- Mechanical faults possible (e.g. snagging on product carriers) → in practice by suitable ball size and Guided Tours minimize.
- Not for closed reactors/explosion pressure restraint.
- No substitution of PPE/suction, but building block in the chain of measures.
✅ Checklist for purchasing Euro-Matic balls
- Medium/temperature, material (PP/HDPE/PVDF)
- Pool area, ball diameter, required quantity
- Coverage & emissions target
- Influence on processes (product carriers, stirrers, sensors)
- Cleaning/Service, Warranty
FAQ
How much energy can I realistically save?
Depending on the application, often > 50%, in hot baths are ≈ 70-75% Heat loss reduction possible.
Are cover balls chemical resistant?
Yes – choose the right material: PP/HDPE for many media, PVDF for aggressive chemicals.
How quickly does it pay for itself?
In thermally stressed applications often < 12-24 months, depending on energy price, bath size and running times.
Do the balls interfere with the movement of the parts?
With correct Size choice and simple Guided Tours typically not – if in doubt, test with a pilot.
What about occupational safety?
Fewer aerosols/vapours and splashes, but still PSA and customized Extraction Mandatory.
