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

Plastic Teller Rosette and Plastic Raschig Ring represent two very different approaches to plastic random packing. Teller Rosette uses a multi-loop geometry to create a dense network of contacting surfaces, while Raschig Ring uses a much simpler cylindrical flow passage.

DAIER's comparable product data show a clear but size-dependent trade-off:

Smaller Teller Rosette models provide substantially greater geometric surface area, while Plastic Raschig Ring generally provides a simpler bed and lower dry packing factor in comparable size classes.

As packing size increases, however, Teller Rosette's surface-area advantage can become much smaller.

Therefore the correct question is not:

Which packing is more efficient?

It is:

Does this tower genuinely need the additional geometric contacting area of Teller Rosette, or would the simpler and more hydraulically open Raschig Ring be the better engineering choice?

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1. Direct Answer

Choose Plastic Teller Rosette more readily when:

• high geometric surface-area density is important;
• the process is relatively clean;
• gas-liquid contacting is a strong priority;
• the selected Teller size provides enough hydraulic margin;
• Teller Rosette is already proven in the existing service.

Choose Plastic Raschig Ring more readily when:

• simple flow passages are valuable;
• lower dry packing factor is important;
• fouling or deposits make simple geometry attractive;
• the existing tower already uses Raschig Rings successfully;
• the additional Teller surface area becomes small at the selected large size.

The key principle is:

Teller Rosette's advantage is strongest when its extra geometric surface area is actually meaningful.

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2. Product Size Ranges

DAIER's Plastic Teller Rosette series includes approximately:

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

Plastic Raschig Ring includes approximately:

• 16 mm;
• 25 mm;
• 38 mm;
• 50 mm;
• 80 mm.

Because the two families do not share every nominal size, this article distinguishes between:

Exact comparison

• 25 vs 25 mm.

Near-size comparisons

• 47/51 mm Teller vs 50 mm Raschig;
• 73 mm Teller vs 80 mm Raschig.

Near-size comparisons are useful for product positioning but should not be treated as exact same-size performance data.

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3. Exact 25 mm Comparison

This one table already defines the two product positions very clearly.

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4. Teller Rosette Has Much More Surface Area at 25 mm

At 25 mm:

Teller Rosette

269 m²/m³

Raschig Ring

205 m²/m³

Teller Rosette provides approximately:

31% more geometric surface area.

That is a meaningful difference.

Where:

• high potential wetted area;
• strong gas-liquid contacting

are important, 25 mm Teller Rosette deserves serious evaluation.

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5. But Raschig Ring Has Much Higher Void Fraction

At the same 25 mm size:

Teller Rosette

82%.

Raschig Ring

90%.

The Raschig Ring bed therefore provides:

8 percentage points more catalog free volume.

That is substantial.

So the direct trade-off becomes:

Teller Rosette → More Geometric Area

versus:

Raschig Ring → More Open Bed Volume

Neither parameter should be ignored.

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6. Packing Factor Tells the Same Hydraulic Story

At 25 mm:

Teller Rosette

488 m⁻¹.

Raschig Ring

400 m⁻¹.

Teller Rosette therefore occupies the higher dry-packing-factor position.

This supports a preliminary interpretation that the Teller bed is:

• finer;
• more geometrically intensive.

But:

488 vs 400 m⁻¹ is not a measured pressure-drop comparison.

Actual ΔP depends on real tower operating conditions.

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7. Teller Rosette Is Actually Lighter at 25 mm

Despite containing substantially more elements:

Teller Rosette

85 kg/m³.

Raschig Ring

112 kg/m³.

So the higher-area Teller bed is approximately:

27 kg/m³ lighter

in dry bulk density.

This is useful because it prevents another bad assumption:

A denser geometric bed is not necessarily a heavier bed.

Physical geometry and polymer distribution matter.

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8. Packing Population Is Completely Different

At 25 mm:

Teller Rosette

170,000 pcs/m³.

Raschig Ring

50,000 pcs/m³.

Teller contains approximately:

3.4 times as many individual packing elements.

This creates a much finer physical network.

That can help create:

• more contact points;
• more local liquid interaction.

But it can also be less attractive where the process contains:

• solids;
• crystals;
• sticky deposits.

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9. More Elements Do Not Automatically Mean Better Mass Transfer

Packing population is only a physical descriptor.

Actual mass transfer depends on:

• effective wetting;
• liquid distribution;
• gas velocity;
• liquid rate;
• mass-transfer driving force.

Therefore:

170,000 pcs/m³ is not itself an efficiency specification.

The process must actually use the additional surface.

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10. Around 50 mm, Teller's Surface-Area Advantage Becomes Even Larger

The closest Teller models are:

Teller Rosette 47 mm

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

Teller Rosette 51 mm

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

Compare with:

Plastic Raschig Ring 50 mm

• 93 m²/m³;
• 90% void;
• 68 kg/m³;
• 6,500 pcs/m³;
• 177 m⁻¹.

This is a very strong product-position comparison.

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11. Teller Rosette Provides Nearly Twice the Area Around 50 mm

Using 51 mm Teller Rosette:

180 m²/m³

versus 50 mm Raschig Ring:

93 m²/m³.

Teller provides approximately:

94% more geometric surface area.

That is one of the strongest reasons to evaluate Teller Rosette in this size class.

The area difference is too large to dismiss.

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12. Yet the Void Fractions Are Almost the Same

At approximately 50 mm:

Teller Rosette 51 mm

89%.

Plastic Raschig Ring 50 mm

90%.

Only:

1 percentage point

separates them.

That creates an interesting engineering position:

Teller Rosette provides much more geometric area without a large catalog void-fraction penalty in this near-size comparison.

This is much more favorable than the 25 mm comparison.

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13. But Teller Still Has a Higher Packing Factor

Teller 51 mm

255 m⁻¹.

Raschig 50 mm

177 m⁻¹.

So even though voidage is nearly identical:

their dry packing factors remain very different.

This is another important example showing that:

void fraction and packing factor are not interchangeable.

Two beds can have almost the same free-volume percentage while occupying very different hydraulic geometry positions.

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14. Why Can Similar Voidage Produce Different Packing Factors?

Void fraction measures:

total open volume inside the packed bed.

Packing factor also reflects characteristics related to:

• packing geometry;
• surface structure;
• flow-path complexity.

The Teller Rosette's numerous loops create much more:

• surface;
• geometric interaction

within approximately the same total free-volume range.

So:

similar voidage does not mean similar hydraulic behavior.

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15. Around 50 mm Teller Is Also Slightly Lighter

Bulk density:

Teller Rosette 51 mm

57 kg/m³.

Raschig Ring 50 mm

68 kg/m³.

So Teller Rosette provides:

• much more geometric area;
• similar voidage;
• slightly lower dry bed weight.

Its main trade-off remains:

higher packing factor and much higher element population.

This makes the ~50 mm class particularly interesting.

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16. Packing Population Remains Much Higher

Teller 51 mm

25,000 pcs/m³.

Raschig 50 mm

6,500 pcs/m³.

The Teller bed contains almost:

four times as many elements.

So although total free volume is similar, the internal distribution of that free volume is very different.

That can affect:

• wetting;
• local flow paths;
• fouling behavior.

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17. Which Is More Attractive Around 50 mm?

Teller Rosette becomes attractive when:

• high geometric contact area matters;
• service is clean;
• the higher packing-factor position is hydraulically acceptable.

Raschig Ring becomes attractive when:

• simpler flow passages matter;
• lower packing factor is important;
• high area density is unnecessary.

This is not:

modern vs old packing.

It is:

high-area complex geometry vs simple lower-factor geometry.

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18. 73 mm Teller vs 80 mm Raschig Changes the Story Again

Compare the larger near-size models.

Teller Rosette 73 mm

• 94 m²/m³;
• 90% void;
• 50 kg/m³;
• 8,000 pcs/m³;
• 180 m⁻¹.

Plastic Raschig Ring 80 mm

• 90 m²/m³;
• 95% void;
• 66 kg/m³;
• 1,820 pcs/m³;
• 130 m⁻¹.

Now the surface-area difference is tiny.

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19. Teller's Area Advantage Almost Disappears at Large Size

Surface area:

Teller 73 mm

94 m²/m³.

Raschig 80 mm

90 m²/m³.

Difference:

only 4 m²/m³.

That is less than:

5%.

Compare this with:

25 mm

269 vs 205.

And:

~50 mm

180 vs 93.

The value of Teller's additional geometry has become much smaller.

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20. This Is the Most Important Insight of the Article

As Teller Rosette size increases, its surface-area advantage over comparable Raschig Ring can shrink dramatically.

At approximately:

25 mm

Teller area advantage ≈ 31%.

50 mm

Teller area advantage ≈ 94%.

73/80 mm

Teller area advantage ≈ 4%.

The relationship is not linear.

Therefore:

Do not assume that because small Teller Rosette has a strong area advantage, large Teller Rosette must also have a strong area advantage.

Exact size matters.

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21. Large Raschig Ring Has Much Higher Void Fraction

At 73/80 mm:

Teller

90%.

Raschig

95%.

So Plastic Raschig Ring provides:

5 percentage points more free volume

while giving up very little geometric surface area.

This gives the large Raschig Ring a particularly strong product position.

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22. Large Raschig Ring Also Has Lower Packing Factor

Teller 73 mm

180 m⁻¹.

Raschig 80 mm

130 m⁻¹.

Combined with:

• almost identical geometric area;
• higher voidage;

the Raschig Ring becomes particularly attractive where:

• hydraulic openness;
• simpler geometry

matter.

Again, actual pressure drop still requires operating data.

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23. Teller Remains Lighter

Bulk density:

Teller 73 mm

50 kg/m³.

Raschig 80 mm

66 kg/m³.

So Teller retains one useful characteristic:

lower dry packing weight.

However, the difference is much less decisive than the hydraulic/geometry differences for many applications.

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24. Packing Population Remains Very Different at Large Size

Teller 73 mm

8,000 pcs/m³.

Raschig 80 mm

1,820 pcs/m³.

Teller still creates more than:

four times the number of individual elements.

Yet surface area is almost identical.

This tells us something very important:

At large size, Teller Rosette's much finer element population no longer translates into a major surface-area advantage over this Raschig Ring model.

That deserves engineering attention.

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25. When Does Teller Rosette's Complex Geometry Stop Paying Off?

There is no universal cutoff size.

But the 73/80 mm comparison illustrates the question engineers should ask:

How much additional surface area am I actually getting for the added geometric complexity?

If the difference becomes only a few m²/m³ while Raschig Ring provides:

• more voidage;
• lower packing factor;
• simpler passages;

the Raschig option may become much more attractive.

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26. Which Is Better for High Contacting-Area Priority?

Small and mid-size classes

Teller Rosette has a strong advantage.

Especially around 50 mm:

180 vs 93 m²/m³

is substantial.

Large size class

The advantage can become small.

Therefore:

high contact-area duty does not automatically mean Teller Rosette at every size.

Compare the exact model.

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27. Which Is Better for Low Pressure-Drop Screening?

Plastic Raschig Ring has the lower dry packing factor in all of the directly or near-comparable examples used here:

25 mm

400 vs 488 m⁻¹.

~50 mm

177 vs 255.

~75–80 mm

130 vs 180.

That gives Raschig Ring a consistently lower packing-factor position.

But actual ΔP still depends on:

• gas load;
• liquid load;
• fluid properties;
• packed height.

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28. Which Is Better for Fouling?

Plastic Raschig Ring deserves stronger consideration as fouling becomes more severe because it uses:

• a very simple cylindrical passage;
• far fewer elements per cubic meter in comparable classes.

Teller Rosette contains many:

• loops;
• contact points;
• local passages.

These can be useful for contacting but potentially less attractive for:

• crystallizing service;
• sticky deposits;
• solids.

Neither packing should be called:

• non-clogging;
• self-cleaning.

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29. Fine Teller Rosette Requires More Fouling Caution

At 25 mm:

170,000 pcs/m³

is an extremely high element population.

Where the process contains substantial:

• solids;
• deposits;
• biological growth;

a highly populated bed may require more caution.

In clean service, however, that fine geometry may be precisely what gives Teller Rosette its desired contacting position.

So:

fouling risk changes whether complexity is an advantage or liability.

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30. Which Is Better for a Weight-Sensitive Tower?

Teller Rosette is lighter in all three representative comparisons:

25 mm

85 vs 112 kg/m³.

~50 mm

57 vs 68.

~75–80 mm

50 vs 66.

That can be useful in:

• FRP equipment;
• lightweight vessels;
• retrofit projects.

However:

structural weight should not override hydraulic or process requirements.

A lighter packing that cannot meet tower duty is not the better selection.

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31. Existing Raschig Ring Tower: When Might Teller Rosette Be Worth Evaluating?

Teller Rosette may deserve evaluation when:

• existing contacting is insufficient;
• process duty increased;
• additional geometric surface area is valuable;
• hydraulic margin is available.

The ~50 mm class is especially interesting because Teller provides:

180 vs 93 m²/m³

with almost the same void fraction.

That is a legitimate retrofit reason.

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32. Existing Raschig Ring Tower: When Should You Keep Raschig?

Keep Raschig Ring when:

• existing performance is satisfactory;
• simple geometry is valued;
• fouling is important;
• hydraulic margin is limited;
• like-for-like replacement minimizes risk.

At the large ~75–80 mm class, changing to Teller may offer:

• little additional area;

while increasing:

• packing factor;
• packing population.

That conversion may have little justification.

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33. Existing Teller Rosette Tower: When Might Raschig Be Considered?

Possible reasons include:

• high pressure-drop concern;
• recurring fouling;
• desire for simpler passages;
• process duty no longer requires very high area.

At large size, Raschig can become especially interesting because the area penalty may be small.

But at ~50 mm:

180 → 93 m²/m³

is a very large surface-area reduction.

So the process duty must be reviewed carefully.

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34. Do Not Automatically Keep the Same Packed Height

Changing Teller ↔ Raschig changes:

• surface area;
• packing factor;
• element population;
• wetting behavior.

Therefore:

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

A geometry retrofit should review:

• required transfer duty;
• hydraulics;
• packed height.

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35. Tower Diameter Still Controls the Size Class

Large packing must be reasonable relative to tower ID.

A large 80 mm Raschig Ring or 73 mm Teller Rosette should not be selected for a very narrow tower simply because catalog hydraulic data look favorable.

Large elements can create:

• wall effects;
• too few elements across the tower.

The better sequence is:

Tower Diameter → Appropriate Size Range → Teller vs Raschig Comparison

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36. Polymer Compatibility Is a Separate Decision

Both products are plastic random packings.

But the actual polymer must still be selected for:

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

The correct geometry made from an incompatible polymer remains an incorrect selection.

Do not choose material from:

• pH alone;
• product color;
• generic “plastic resistance” claims.

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37. Support Grid Compatibility

Teller Rosette and Raschig Ring have very different physical shapes.

A packing-family conversion should therefore check:

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

The smallest characteristic element dimension—not just the nominal size—should be considered.

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38. Hold-Down Review

Both products are relatively lightweight.

For high upward gas velocity, packing movement may become a concern.

Check:

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

The purpose is to:

restrain excessive movement

not compress the random bed.

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Decision Table

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39. Quick Selection Guide

25 mm

Choose between:

Teller → much more area + lighter bed

and:

Raschig → higher voidage + lower packing factor + simpler geometry.

Around 50 mm

Teller becomes particularly attractive for contacting:

180 vs 93 m²/m³

with nearly the same void fraction.

Raschig still provides:

much lower dry packing factor.

Around 75–80 mm

The geometric-area difference nearly disappears.

Raschig then provides:

• higher voidage;
• lower packing factor;
• much fewer elements.

This can significantly strengthen the Raschig position.

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Common Selection Mistakes

Assuming Teller Rosette Always Has Dramatically More Surface Area

Not at the large 73/80 mm class.

Assuming Raschig Ring Always Has Much Less Contacting Area

The difference can become very small at larger sizes.

Choosing Teller Only from Surface Area

Packing factor, fouling and size also matter.

Choosing Raschig Only Because It Is Simpler

At ~50 mm Teller provides nearly twice the geometric area with similar voidage.

Assuming Similar Void Fraction Means Similar Hydraulics

The ~50 mm packing factors differ substantially.

Comparing Packing Population as an Efficiency Measure

Four times more elements does not necessarily mean four times more useful area.

Treating 51 vs 50 mm or 73 vs 80 mm as Exact Comparisons

They are near-size classes.

Changing Packing Family Without Reviewing Bed Height

That is a retrofit.

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Frequently Asked Questions

Which has more surface area, Teller Rosette or Plastic Raschig Ring?

Teller Rosette has substantially more surface area at small and mid-size comparable models, but the difference becomes very small in the 73 vs 80 mm comparison.

What is the exact 25 mm comparison?

Teller Rosette:

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

Plastic Raschig Ring:

• 205 m²/m³;
• 90% void;
• 112 kg/m³;
• 50,000 pcs/m³;
• 400 m⁻¹.

Which has higher void fraction at 25 mm?

Plastic Raschig Ring: approximately 90% vs 82%.

What happens around 50 mm?

Teller Rosette provides approximately 180–185 m²/m³, while Plastic Raschig Ring 50 mm provides approximately 93 m²/m³. Their void fractions are relatively close, but Raschig Ring has the lower dry packing factor.

What happens at large size?

Teller Rosette 73 mm provides approximately 94 m²/m³, while Raschig Ring 80 mm provides approximately 90 m²/m³. The surface-area difference is small, while Raschig has higher voidage and lower dry packing factor.

Which is lighter?

Teller Rosette is lighter in the representative matched or near-matched comparisons used here.

Which has lower dry packing factor?

Plastic Raschig Ring in the compared size classes.

Which is better for fouling?

Raschig Ring's simple geometry and lower packing population can make it attractive as fouling risk increases, but final selection depends on the deposit mechanism.

Can Teller Rosette directly replace Raschig Ring?

Do not treat it as like-for-like. Geometry and physical bed properties differ substantially.

Which is better for a scrubber?

It depends on required contacting area, gas/liquid loads, fouling, tower diameter and polymer compatibility.

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Selection Takeaway

Plastic Teller Rosette vs Plastic Raschig Ring is fundamentally a question of whether the process gets enough value from Teller Rosette's additional geometric complexity.

At 25 mm:

Teller → 269 m²/m³ / 82% void / 85 kg/m³ / 170,000 pcs/m³ / 488 m⁻¹

versus:

Raschig → 205 m²/m³ / 90% void / 112 kg/m³ / 50,000 pcs/m³ / 400 m⁻¹.

At approximately 50 mm:

Teller 51 mm → 180 m²/m³ / 89% void / 57 kg/m³ / 25,000 pcs/m³ / 255 m⁻¹

versus:

Raschig 50 mm → 93 m²/m³ / 90% void / 68 kg/m³ / 6,500 pcs/m³ / 177 m⁻¹.

Here Teller's area advantage is extremely strong.

But at the larger size class:

Teller 73 mm → 94 m²/m³ / 90% void / 50 kg/m³ / 8,000 pcs/m³ / 180 m⁻¹

versus:

Raschig 80 mm → 90 m²/m³ / 95% void / 66 kg/m³ / 1,820 pcs/m³ / 130 m⁻¹.

Now the area advantage has nearly disappeared.

This gives the article's most important engineering conclusion:

The value of Teller Rosette's complex loop geometry is highly size-dependent. At small and mid sizes it can provide a major geometric-area advantage; at larger sizes that advantage may shrink enough that Raschig Ring's higher voidage, lower packing factor and simpler geometry become more attractive.

The correct selection sequence is:

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