Plastic Teller Rosette vs Plastic Ralu Ring: Which Random Packing Should You Select?

Plastic Teller Rosette and Plastic Ralu Ring are both lightweight plastic random packings, but their packed-bed structures are very different. Teller Rosette generally creates a denser network of looped contacting elements with high geometric surface area, while Ralu Ring can provide a lighter and more open bed in several comparable size classes.

The correct selection question is therefore:

Does the process need maximum geometric contacting area from a fine rosette-type bed, or does it benefit more from a lighter and more hydraulically open ring-type packing?

Neither family should be selected from appearance alone.

---

1. Direct Answer

Choose Plastic Teller Rosette more readily when:

• high geometric surface-area density is important;
• the process is relatively clean;
• strong gas-liquid contacting is a priority;
• the tower can tolerate a finer packed-bed structure;
• Teller Rosette is already proven in the existing service.

Evaluate Plastic Ralu Ring more strongly when:

• higher void fraction is valuable;
• lower packed-bed weight matters;
• lower packing population is desirable;
• fouling or solids make a coarser bed attractive;
• the project wants a more open plastic random-packing position.

The core trade-off is:

Teller Rosette → Higher Contact-Area Density

versus:

Ralu Ring → Lighter / More Open Bed Position

But the exact answer changes with size.

---

2. Product Families and Available Sizes

DAIER's Teller Rosette series includes nominal sizes approximately:

• 25 mm;
• 47 mm;
• 51 mm;
• 59 mm;
• 73 mm;
• 95 mm;
• 145 mm.

The Ralu Ring series includes approximately:

• 15 mm;
• 25 mm;
• 38 mm;
• 50 mm;
• 90 mm;
• 125 mm.

The cleanest comparison is:

25 mm vs 25 mm

while the larger products can be compared by similar commercial size class:

• 47/51 mm Teller vs 50 mm Ralu;
• 95 mm Teller vs 90 mm Ralu.

These near-size comparisons should not be treated as exact dimensional equivalents.

---

3. 25 mm Exact Same-Size Comparison

This comparison immediately reveals that the products occupy very different bed positions.

---

4. Teller Rosette Provides Much More Area at 25 mm

At 25 mm:

Teller Rosette

269 m²/m³

Ralu Ring

190 m²/m³

The difference is:

79 m²/m³

or roughly:

42% more geometric surface area

for Teller Rosette.

This is a real advantage where geometric contacting area is important.

But the additional surface is achieved through a much finer packed-bed structure.

---

5. Ralu Ring Has Higher Void Fraction at 25 mm

The verified values are:

Teller Rosette

82%

Ralu Ring

88%.

So Ralu Ring provides:

6 percentage points more free bed volume.

That is a substantial difference for two products with the same nominal size.

It demonstrates that:

nominal diameter does not define packed-bed openness.

Internal geometry matters.

---

6. Bed Weight Is Also Very Different

At 25 mm:

Teller Rosette

85 kg/m³.

Ralu Ring

46.8 kg/m³.

Ralu Ring is therefore approximately:

38 kg/m³ lighter

in dry packed-bed density.

For a 20 m³ bed:

Teller Rosette

20 × 85 =

1,700 kg

Ralu Ring

20 × 46.8 ≈

936 kg

Difference:

approximately 764 kg of dry packing.

This can matter for:

• support-grid loading;
• freight;
• installation handling.

---

7. Packing Population Is Even More Dramatically Different

At 25 mm:

Teller Rosette

170,000 pcs/m³.

Ralu Ring

36,000 pcs/m³.

Teller Rosette contains almost:

4.7 times as many individual elements per cubic meter.

This produces a much finer bed network.

That can be beneficial for:

• liquid contacting;
• redistribution at the element scale.

But it can also make the bed less attractive where:

• fouling;
• suspended solids;
• deposits

are major concerns.

---

8. More Pieces Do Not Automatically Mean Better Performance

The very high Teller Rosette population creates many:

• contact points;
• liquid-interaction surfaces;
• geometric passages.

But actual mass-transfer efficiency still depends on:

• wetting;
• gas flow;
• liquid load;
• fluid properties;
• distribution quality.

Therefore:

170,000 pcs/m³ is not automatically better than 36,000 pcs/m³.

It describes a different packed-bed structure.

---

9. Teller Rosette Has a Verified Dry Packing Factor at 25 mm

The 25 mm Teller Rosette has a catalog dry packing factor of approximately:

488 m⁻¹.

The current verified Ralu Ring dataset does not provide dry packing factor.

Therefore:

we should not invent a Ralu Ring value or claim a numerical packing-factor advantage.

This is important because higher void fraction alone does not prove:

• lower actual pressure drop;
• higher capacity.

Hydraulic performance requires proper operating data.

---

10. Can We Say 25 mm Ralu Ring Has Lower Pressure Drop?

Not as a guaranteed statement.

Ralu Ring has:

• higher void fraction;
• lower packing population;
• much lower bulk density.

Those characteristics make it a strong candidate for hydraulic screening.

But actual pressure drop depends on:

• gas velocity;
• liquid load;
• tower diameter;
• fluid properties;
• bed height.

So the correct statement is:

25 mm Ralu Ring occupies a more open physical bed position, but actual ΔP must be evaluated for the specific tower.

---

11. Around 50 mm, the Comparison Changes

Teller Rosette provides:

47 mm

• 185 m²/m³;
• 88% void;
• 58 kg/m³;
• 32,500 pcs/m³;
• 271 m⁻¹.

51 mm

• 180 m²/m³;
• 89% void;
• 57 kg/m³;
• 25,000 pcs/m³;
• 255 m⁻¹.

Ralu Ring 50 mm provides:

• 110 m²/m³;
• 95% void;
• 53.5 kg/m³;
• 6,300 pcs/m³.

These are near-size-class comparisons rather than exact matches.

---

12. Teller Rosette Still Has Much More Surface Area Around 50 mm

Using Teller Rosette 51 mm against Ralu Ring 50 mm:

Teller Rosette

180 m²/m³.

Ralu Ring

110 m²/m³.

That is about:

64% more geometric surface area

for the Teller Rosette.

So the high-area position remains very strong.

---

13. Ralu Ring Is Much More Open Around 50 mm

Void fractions:

Teller Rosette 51 mm

89%.

Ralu Ring 50 mm

95%.

Again the Ralu bed has substantially more free volume.

So the near-50 mm choice is particularly clear:

Teller Rosette → much more area

versus:

Ralu Ring → much higher void fraction.

That is a genuine engineering trade-off.

---

14. Dry Bed Weight Is Surprisingly Similar Around 50 mm

Teller Rosette 51 mm:

57 kg/m³

Ralu Ring 50 mm:

53.5 kg/m³.

The difference is only:

3.5 kg/m³.

This is interesting because the 25 mm comparison showed a very large weight difference.

So:

the relative bed-weight advantage of Ralu Ring becomes much smaller around the 50 mm class.

Once again, family-level claims should not replace exact model data.

---

15. Element Population Still Differs Strongly Around 50 mm

Teller Rosette 51 mm:

25,000 pcs/m³

Ralu Ring 50 mm:

6,300 pcs/m³.

The Teller bed still contains almost:

four times as many elements.

That finer element network helps explain how Teller Rosette maintains very high surface-area density.

---

16. Why This Matters for Fouling

A fine packed bed with many individual elements can create:

• more contact points;
• more narrow local passages.

Where the process contains:

• solids;
• crystals;
• biological growth;
• sticky material;

a coarser bed may deserve stronger consideration.

Therefore Ralu Ring may move higher as fouling risk increases.

But:

Ralu Ring should not be described as clog-free.

Severe fouling may require an even more open packing family or a process change.

---

17. Around 90–95 mm, the Difference Narrows Again

Compare:

Teller Rosette 95 mm

• 98 m²/m³ surface area;
• 92% void;
• 52 kg/m³ bulk density;
• 3,900 pcs/m³;
• 129 m⁻¹ dry packing factor.

Ralu Ring 90 mm

• 75 m²/m³;
• 90% void;
• 40 kg/m³;
• 1,000 pcs/m³.

These sizes are close, but not identical.

This comparison is important because the product-family relationship changes again.

---

18. Teller Rosette Still Has Higher Surface Area Around 90 mm

Surface area:

Teller 95 mm

98 m²/m³.

Ralu 90 mm

75 m²/m³.

Teller remains ahead by:

23 m²/m³

or about:

31%.

But unlike the 25 mm comparison, the void-fraction advantage now belongs slightly to Teller Rosette:

• Teller — 92%;
• Ralu — 90%.

This demonstrates again that:

there is no universal rule saying Ralu Ring always has higher voidage than Teller Rosette.

---

19. Ralu Ring Is Still Lighter Around 90 mm

Bulk density:

Teller Rosette 95 mm

52 kg/m³.

Ralu Ring 90 mm

40 kg/m³.

Ralu Ring remains lighter by:

12 kg/m³.

It also has far fewer packing elements:

• Teller — 3,900 pcs/m³;
• Ralu — 1,000 pcs/m³.

So Ralu remains the coarser physical bed.

---

20. Why the 90–95 mm Comparison Is Especially Useful

At smaller sizes, Teller Rosette's higher area comes with clearly lower voidage.

At the 90–95 mm class, Teller Rosette provides:

• higher surface area;
• slightly higher void fraction.

That means:

size can fundamentally change the engineering position of the same packing family.

A statement that is true for:

25 mm Teller Rosette

may not remain true for:

95 mm Teller Rosette.

Exact size matters.

---

21. Teller Rosette Becomes Much More Open as Size Increases

The Teller Rosette series changes substantially.

25 mm

• 269 m²/m³;
• 82% void;
• 488 m⁻¹.

51 mm

• 180 m²/m³;
• 89% void;
• 255 m⁻¹.

95 mm

• 98 m²/m³;
• 92% void;
• 129 m⁻¹.

145 mm

• 65 m²/m³;
• 95% void;
• 76 m⁻¹.

So larger Teller Rosette models shift strongly toward:

• higher void fraction;
• lower packing factor;
• lower packing population.

That means Teller Rosette itself spans several very different hydraulic positions.

---

22. Ralu Ring Also Has Strongly Non-Linear Size Behavior

Ralu Ring data include:

15 mm

• 320 m²/m³;
• 94% void;
• 80 kg/m³;
• 170,000 pcs/m³.

25 mm

• 190 m²/m³;
• 88% void;
• 46.8 kg/m³;
• 36,000 pcs/m³.

38 mm

• 150 m²/m³;
• 95% void;
• 65 kg/m³;
• 13,500 pcs/m³.

50 mm

• 110 m²/m³;
• 95% void;
• 53.5 kg/m³;
• 6,300 pcs/m³.

90 mm

• 75 m²/m³;
• 90% void;
• 40 kg/m³;
• 1,000 pcs/m³.

125 mm

• 60 m²/m³;
• 97% void;
• 30 kg/m³;
• 800 pcs/m³.

The void fraction is clearly non-monotonic.

Therefore:

larger Ralu Ring does not automatically mean progressively higher voidage.

---

23. Product Family Alone Cannot Predict Voidage

This comparison gives several counterexamples.

At 25 mm:

Ralu has higher voidage.

Around 50 mm:

Ralu again has higher voidage.

Around 90–95 mm:

Teller has slightly higher voidage.

Therefore:

the exact supplier model and size must be compared.

This is much more reliable than saying:

• Rosette is dense;
• Ralu is open.

Those descriptions are only broad tendencies.

---

24. Which Is Better for High Contacting Area?

Teller Rosette generally has the stronger position in the comparable size classes examined here.

At:

• 25 mm;
• ~50 mm;
• ~90–95 mm,

Teller provides more geometric surface area.

This makes it a strong candidate where:

• high contact-area density;
• clean service;
• strong gas-liquid contacting

are priorities.

Effective mass transfer still requires actual wetting and operating conditions.

---

25. Which Is Better for a Coarse Open Bed?

Ralu Ring deserves stronger consideration when the selected model provides:

• high void fraction;
• low element population;
• low dry bed weight.

This is especially evident at:

• 25 mm;
• 38 mm;
• 50 mm.

However, at 90 mm, the verified Ralu void fraction drops to 90%.

So even this decision remains:

model-specific.

---

26. Which Is Better for Weight-Sensitive Towers?

Ralu Ring generally has the lighter catalog position in the comparable examples.

Examples:

25 mm

46.8 vs 85 kg/m³.

~50 mm

53.5 vs 57 kg/m³.

~90 mm

40 vs 52 kg/m³.

This can matter for:

• old tower supports;
• lightweight scrubbers;
• retrofit projects;
• installation logistics.

But structural weight is only one selection variable.

---

27. Which Is Better for High Gas Throughput?

The answer depends strongly on the exact model.

At 25 and ~50 mm, Ralu's higher voidage makes it attractive for hydraulic screening.

But Teller Rosette size increase can dramatically improve its own openness.

For example:

145 mm Teller Rosette reaches 95% void fraction and 76 m⁻¹ dry packing factor.

Therefore:

high gas throughput does not automatically eliminate Teller Rosette.

The correct size must be considered.

---

28. Which Is Better for Fouling?

Broadly:

Teller Rosette

has more:

• individual elements;
• loop structure;
• contacting geometry.

Ralu Ring

can create:

• lower element population;
• coarser bed structure.

As fouling becomes more serious, the Ralu geometry may deserve stronger screening.

But actual fouling depends on:

• deposit type;
• solids concentration;
• crystal growth;
• biological activity;
• cleaning procedure.

No plastic random packing is universally fouling-resistant.

---

29. Existing Teller Rosette Tower: Should You Change to Ralu Ring?

Possible reasons include:

• recurring fouling;
• hydraulic constraints;
• desire to reduce bed weight;
• desire for a coarser element population.

For example, changing:

~50 mm Teller → 50 mm Ralu

can substantially reduce:

• geometric surface area;
• packing population;

while increasing:

• void fraction.

That is not a simple product replacement.

It is a packed-bed retrofit.

---

30. Existing Ralu Ring Tower: Should You Change to Teller Rosette?

Possible reasons include:

• insufficient contacting;
• need for more geometric surface area;
• changed process duty.

At 25 mm:

190 → 269 m²/m³

is a large increase in geometric area.

But void fraction falls:

88% → 82%.

And dry bed weight rises.

So:

Ralu → Teller should only be considered when the additional contact-area density has real process value.

---

31. Same Nominal Size Does Not Mean Equivalent Hydraulic Behavior

The 25 mm comparison proves this immediately.

Both are nominally:

25 mm.

Yet:

• surface area differs 42%;
• voidage differs 6 percentage points;
• dry density differs dramatically;
• packing population differs by almost 5×.

Therefore:

25 mm is only a size label—not a performance specification.

---

32. Do Not Automatically Keep the Same Packed Height After Conversion

Changing packing family changes:

• geometric surface area;
• wetting behavior;
• void fraction;
• packing population;
• hydraulic characteristics.

Therefore:

same nominal size + same bed height does not guarantee equivalent tower performance.

Any Teller ↔ Ralu conversion should review:

• required mass transfer;
• hydraulic operation;
• packed height.

---

33. Tower Diameter Must Be Considered

Large Teller and Ralu models require enough tower diameter to develop a reasonable random bed.

For example:

• 125 mm Ralu;
• 145 mm Teller

should not be selected for a small column merely because their packing factor or void fraction looks attractive.

Large elements in small towers can produce:

• wall effects;
• poor random distribution.

Tower ID must be known before final size selection.

---

34. Material Compatibility Is Separate from Geometry

Both products are plastic random packings.

But:

plastic is not one universal material.

Depending on product availability, material may include:

• PP;
• other suitable polymers.

Compatibility depends on:

• chemical species;
• concentration;
• temperature;
• oxidizers;
• solvents.

Do not select Teller vs Ralu before confirming that the available polymer is suitable.

---

35. Support Grid Compatibility

The two product geometries have different:

• characteristic dimensions;
• shapes;
• retention behavior.

A conversion should therefore check:

• support-grid opening;
• packing retention;
• support open area.

A grid that retains a large Teller Rosette may not automatically be appropriate for a much smaller Ralu Ring.

---

36. Hold-Down Review

Both are lightweight plastic random packings.

Under sufficiently high gas velocity, packing movement can occur.

The project should review:

• hold-down grid;
• bed limiter;
• upper restraint.

The hold-down should:

prevent excessive movement

not:

compress the bed.

---

Decision Table

---

37. Quick Selection Guide

Favor Teller Rosette when:

• high geometric surface-area density is important;
• process is clean;
• strong contacting is desired;
• selected size remains hydraulically suitable.

Favor Ralu Ring for stronger evaluation when:

• a lighter bed is desirable;
• a coarser element population is useful;
• 25–50 mm high voidage is attractive;
• moderate fouling risk exists.

For larger sizes:

Do not carry small-size assumptions upward.

Compare the actual:

• surface area;
• void fraction;
• bulk density;
• packing population

of the selected model.

---

Common Selection Mistakes

Saying Teller Rosette Is Always Too Dense

Large Teller models can have very high void fraction and much lower packing factor.

Saying Ralu Ring Always Has Higher Void Fraction

The ~90–95 mm comparison does not support that.

Selecting Teller Only Because It Has More Surface Area

Hydraulic and fouling effects also matter.

Selecting Ralu Only Because It Is Lighter

Mass-transfer duty still has to be achieved.

Comparing Only Nominal Size

The same 25 mm designation can create radically different beds.

Using Packing Population as an Efficiency Metric

More pieces do not automatically mean better performance.

Inventing Ralu Packing Factor

The current verified dataset does not provide it.

Changing Packing Family Without Reviewing Bed Height

It is a retrofit, not a simple substitution.

---

Frequently Asked Questions

Which has more surface area, Teller Rosette or Ralu Ring?

In the comparable 25 mm, ~50 mm and ~90–95 mm examples, Teller Rosette provides higher geometric surface area.

What is the 25 mm comparison?

Teller Rosette:

• 269 m²/m³;
• 82% void;
• 85 kg/m³;
• 170,000 pcs/m³;
• 488 m⁻¹.

Ralu Ring:

• 190 m²/m³;
• 88% void;
• 46.8 kg/m³;
• 36,000 pcs/m³.

Which is more open at 25 mm?

Ralu Ring by verified void fraction: approximately 88% versus 82%.

Which is lighter at 25 mm?

Ralu Ring: approximately 46.8 kg/m³ versus 85 kg/m³.

What happens around 50 mm?

Teller Rosette still provides much more geometric area, while Ralu Ring provides substantially higher void fraction and far fewer elements per cubic meter.

Which has higher void fraction around 90 mm?

The near-size comparison gives approximately 92% for Teller Rosette 95 mm versus 90% for Ralu Ring 90 mm.

Does Ralu Ring always have lower pressure drop?

The current verified Ralu dataset does not provide dry packing factor, so that numerical claim should not be made without additional hydraulic data.

Which is better for fouling?

Ralu Ring's coarser bed position can make it attractive for fouling-sensitive service, but severe fouling may require another packing family.

Can Teller Rosette directly replace Ralu Ring?

Do not treat it as like-for-like. Geometry, surface area, voidage, bed weight and packing population differ.

Which should be selected for a scrubber?

The answer depends on gas/liquid loads, required removal, fouling, tower diameter and material compatibility—not the application label alone.

---

Selection Takeaway

Plastic Teller Rosette vs Plastic Ralu Ring is fundamentally a choice between a finer, high-contact-area bed and a lighter, generally coarser ring-type bed—but the relationship changes materially with size.

At 25 mm:

Teller Rosette → 269 m²/m³ / 82% void / 85 kg/m³ / 170,000 pcs/m³

versus:

Ralu Ring → 190 m²/m³ / 88% void / 46.8 kg/m³ / 36,000 pcs/m³.

Around 50 mm:

Teller Rosette 51 mm → 180 m²/m³ / 89% void / 57 kg/m³ / 25,000 pcs/m³

versus:

Ralu Ring 50 mm → 110 m²/m³ / 95% void / 53.5 kg/m³ / 6,300 pcs/m³.

Around 90–95 mm:

Teller Rosette 95 mm → 98 m²/m³ / 92% void / 52 kg/m³ / 3,900 pcs/m³

versus:

Ralu Ring 90 mm → 75 m²/m³ / 90% void / 40 kg/m³ / 1,000 pcs/m³.

The key engineering lesson is:

Teller Rosette consistently provides a stronger geometric-area position in these comparisons, while Ralu Ring generally creates a much lower packing population and lighter bed. However, even the void-fraction ranking can reverse as size changes.

Therefore the correct selection sequence is:

Process Duty → Fouling → Tower Diameter → Required Contacting Area → Hydraulic Constraint → Size Class → Compare Exact Teller / Ralu Data → Polymer Compatibility → Internals Review

The key principle is:

Do not choose Teller Rosette because “more surface area is always better,” and do not choose Ralu Ring because “more open is always better.” Select the exact model whose balance of contacting area, voidage, bed weight and packing population solves the actual tower constraint.