Metal Conjugated Ring Size Selection: 16 vs 25 vs 38 vs 50 vs 80 mm

Metal Conjugated Ring size selection changes specific surface area, void fraction, packed-bed weight, element population and dry packing factor. Across DAIER's catalog-confirmed 16–80 mm series, surface area decreases from approximately 313 to 81 m²/m³ and packing population decreases from about 211,250 to 3,980 pieces/m³. However, void fraction is non-monotonic, and the hydraulic benefit of increasing from 50 to 80 mm is much smaller than the size difference alone might suggest.

The verified size series includes:

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

The core selection principle is:

Smaller Metal Conjugated Ring provides substantially more geometric contacting area, while larger models create a much coarser bed—but the largest size does not automatically provide the highest void fraction or a dramatically lower packing factor.

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1. DAIER Metal Conjugated Ring Specifications

DAIER's source catalog confirms this five-model series and these published properties.

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2. What Changes Most as Size Increases?

Three trends are especially clear.

Surface Area Falls

From:

313 m²/m³ at 16 mm

to:

81 m²/m³ at 80 mm.

Packing Population Falls

From:

211,250 pieces/m³

to:

3,980 pieces/m³.

Bulk Density Falls

From:

354 kg/m³

to:

94.5 kg/m³.

This means the bed moves from:

many small, high-area elements

toward:

far fewer, larger and lighter packed elements.

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3. Void Fraction Does Not Increase with Size

The catalog sequence is:

• 16 mm — 97%
• 25 mm — 95%
• 38 mm — 96%
• 50 mm — 96%
• 80 mm — 95%. 

This immediately disproves the simple rule:

larger random packing = higher void fraction.

The highest catalog void fraction is actually found at the smallest 16 mm model.

That makes Metal Conjugated Ring a particularly useful example of why supplier-specific geometry matters.

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4. Why Size Alone Cannot Predict Bed Openness

Nominal diameter affects the characteristic scale of the element, but void fraction also depends on:

• metal thickness;
• formed geometry;
• internal openings;
• random orientation;
• how neighboring elements contact each other.

Therefore:

80 mm can have fewer elements and lower packing factor while still having lower published voidage than 50 mm.

Different indicators of “openness” are not identical.

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5. 16 mm Metal Conjugated Ring

The 16 mm model provides:

• 313 m²/m³ surface area;
• 97% void fraction;
• 354 kg/m³ bulk density;
• 211,250 pcs/m³;
• 324 m⁻¹ packing factor;
• 0.4 mm wall thickness. 

This clearly places it at the:

high-area / very fine-bed

end of the series.

16 mm May Move Higher When

• geometric contacting area is a strong priority;
• process fluids are clean;
• tower diameter favors small random packing;
• hydraulic loading remains manageable.

Main Trade-Offs

It also has:

• the highest element population;
• the highest dry packing factor;
• the highest bulk density.

So the 16 mm product should not be selected simply because it provides the most m²/m³.

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6. 16 vs 25 mm Is Already a Major Change

Moving from 16 to 25 mm changes:

Surface Area

313 → 185 m²/m³

Element Population

211,250 → 75,000 pcs/m³

Bulk Density

354 → 216 kg/m³

Packing Factor

324 → 216 m⁻¹.

But interestingly:

Void Fraction

97% → 95%.

So the larger element creates:

• a much coarser bed;
• lower packing factor;
• lower weight;

without increasing published void fraction.

This is an important distinction.

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7. 25 mm Metal Conjugated Ring

The 25 mm model provides:

• 185 m²/m³ surface area;
• 95% void fraction;
• 216 kg/m³ bulk density;
• 75,000 pcs/m³;
• 216 m⁻¹ packing factor;
• approximately 0.5 mm thickness. 

Compared with 16 mm, it sacrifices substantial geometric area but also greatly reduces:

• element population;
• bed weight;
• packing factor.

This can make 25 mm a stronger candidate where the 16 mm bed would be unnecessarily fine.

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8. 38 mm Metal Conjugated Ring

The 38 mm model provides:

• 116 m²/m³ surface area;
• 96% void fraction;
• 131 kg/m³ bulk density;
• 19,500 pieces/m³;
• 131 m⁻¹ packing factor;
• approximately 0.8 mm thickness. 

Moving from 25 to 38 mm produces:

• lower surface area;
• far fewer packing elements;
• much lower bed weight;
• lower packing factor;

while void fraction actually rises:

95% → 96%.

This makes 38 mm a useful intermediate product position.

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9. Why 38 mm Is an Important Mid-Range Model

At 38 mm, the bed has already moved far away from the fine 16 mm configuration.

Compare:

 

The reduction in element population is more than tenfold.

Therefore:

38 mm is not simply a slightly larger high-area model—it creates a fundamentally coarser packed bed.

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10. 50 mm Metal Conjugated Ring

The 50 mm model provides:

• 86 m²/m³ surface area;
• 96% void fraction;
• 97 kg/m³ bulk density;
• 9,772 pcs/m³;
• 97 m⁻¹ dry packing factor;
• approximately 0.8 mm thickness. 

Compared with 38 mm:

Surface Area

116 → 86 m²/m³

Packing Count

19,500 → 9,772 pcs/m³

Packing Factor

131 → 97 m⁻¹

while void fraction remains:

96%.

This makes the 38-vs-50 mm comparison relatively clean.

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11. 38 vs 50 mm: What Are You Trading?

The 38 mm model provides:

more geometric contacting area

while the 50 mm model provides:

• fewer packing elements;
• lower bed weight;
• lower packing factor.

Both have the same published:

96% void fraction.

Therefore this selection cannot be made from voidage.

It depends much more on:

• required contacting;
• gas/vapor load;
• fouling;
• hydraulic margin.

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12. 80 mm Metal Conjugated Ring

The 80 mm model provides:

• 81 m²/m³ surface area;
• 95% void fraction;
• 94.5 kg/m³ bulk density;
• 3,980 pieces/m³;
• 95 m⁻¹ dry packing factor;
• approximately 0.8 mm thickness. 

It is clearly the coarsest element population in the series.

However, two important surprises appear:

1. void fraction falls from 96% to 95%;
2. packing factor barely changes from 97 to 95 m⁻¹.

This makes 80 mm fundamentally different from the usual expectation of a major hydraulic improvement from a large size increase.

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13. 50 vs 80 mm Is the Most Important Comparison

Compare them directly:

 

The size increases by 60%.

But:

• surface area changes only slightly;
• bulk density changes only slightly;
• packing factor changes only slightly.

The largest change is:

packing population.

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14. Why 80 mm Is Not Automatically a Hydraulic Upgrade from 50 mm

Packing factor changes only:

97 → 95 m⁻¹.

Void fraction actually changes:

96% → 95%.

Therefore:

DAIER's supplier-specific catalog does not support describing 80 mm as a dramatically lower-resistance version of 50 mm.

Its strongest geometric distinction is instead:

far fewer individual packing elements.

That can still matter for:

• fouling;
• large tower operation;
• bed structure.

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15. Packing Factor Trend

The verified sequence is:

• 16 mm — 324 m⁻¹;
• 25 mm — 216 m⁻¹;
• 38 mm — 131 m⁻¹;
• 50 mm — 97 m⁻¹;
• 80 mm — 95 m⁻¹. 

The largest hydraulic-geometric changes occur between:

• 16 → 25;
• 25 → 38;
• 38 → 50.

The 50 → 80 step shows very little further packing-factor reduction.

This is an excellent example of:

diminishing returns from increasing random-packing size.

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16. Packing Factor Is Not Actual Pressure Drop

The 95 vs 97 m⁻¹ values should not be converted into an operating pressure-drop claim.

Actual tower ΔP depends on:

• gas velocity;
• gas density;
• liquid flow;
• liquid properties;
• bed depth.

Therefore:

packing factor is an engineering descriptor/input—not the tower's measured operating pressure drop.

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17. Surface Area Trend Also Shows Diminishing Change

The surface-area reductions are:

16 → 25 mm

313 → 185Decrease: 128 m²/m³

25 → 38 mm

185 → 116Decrease: 69 m²/m³

38 → 50 mm

116 → 86Decrease: 30 m²/m³

50 → 80 mm

86 → 81Decrease: only 5 m²/m³.

That final point is particularly interesting.

Increasing from 50 to 80 mm dramatically reduces element count while barely changing geometric surface-area density.

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18. Size Selection for Contact-Intensive Service

Where:

• process fluids are clean;
• high geometric area is important;

smaller sizes deserve stronger screening.

16 mm

provides the strongest geometric-area position.

25 mm

remains relatively high-area while creating a much coarser bed.

38 mm

moves toward an intermediate balance.

However:

actual effective mass-transfer area cannot be inferred from geometric area alone.

Liquid distribution and operating conditions remain critical.

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19. Size Selection for Higher Gas or Vapor Throughput

As hydraulic requirements become stronger, the selection can move toward:

• 38 mm;
• 50 mm.

The decrease in packing factor supports this direction.

But the catalog provides an important warning:

moving all the way to 80 mm does not produce another large packing-factor reduction.

Therefore 80 mm should have a specific reason—not just “bigger means more capacity.”

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20. Size Selection for Fouling Service

Element population changes dramatically:

• 16 mm — 211,250 pcs/m³;
• 25 mm — 75,000;
• 38 mm — 19,500;
• 50 mm — 9,772;
• 80 mm — 3,980. 

As fouling risk rises, fewer larger elements can become attractive because the packed bed is physically coarser.

This can move:

• 50 mm;
• 80 mm

higher in preliminary screening.

But:

Metal Conjugated Ring is not fouling-proof.

Severe crystallization or sticky solids may require another packing family.

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21. When 80 mm Can Still Make Sense

Although its packing factor is almost the same as 50 mm, 80 mm may still be useful where:

• the tower is large;
• very low packing population is desirable;
• fouling tolerance receives strong priority;
• 81 m²/m³ surface area is still sufficient.

Its strongest distinction is:

3,980 elements/m³ versus 9,772 for 50 mm.

That is a meaningful physical bed change.

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22. Tower Diameter Can Eliminate 80 mm

80 mm random packing requires a sufficiently large vessel.

If the tower is too narrow:

• too few elements span the diameter;
• wall effects increase;
• random-bed uniformity can deteriorate.

Therefore:

the largest Metal Conjugated Ring should never be selected before tower ID is known.

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23. Bulk Density and Support Load

Bulk density declines sharply through the series:

• 354;
• 216;
• 131;
• 97;
• 94.5 kg/m³. 

The difference between 16 and 50 mm is particularly large.

For a 10 m³ bed, based on dry catalog bulk density alone:

• 16 mm corresponds to about 3,540 kg of packing;
• 50 mm corresponds to about 970 kg.

This illustrates why selected packing size can materially affect:

• dry bed load;
• support-grid requirements.

Operating liquid and deposits still add additional load.

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24. Material Grade Is a Separate Selection

This article answers:

Which Metal Conjugated Ring size?

It does not determine:

• SS304;
• SS316L;
• another alloy.

Material compatibility depends on:

• chemical species;
• concentration;
• temperature;
• corrosion mechanism.

A correct size made from an incompatible metal is still the wrong packing.

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25. Replacement Projects Need Exact Identification

Before replacing an existing Metal Conjugated Ring bed, identify:

• actual dimensions;
• metal thickness;
• alloy;
• packed height;
• tower ID;
• support-grid opening.

Do not specify only:

“Metal Conjugated Ring, large size.”

The 50 and 80 mm models have similar packing factors but very different:

• dimensions;
• packing populations.

Exact identification matters.

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26. Changing Size Is an Engineering Retrofit

Changing:

25 mm → 50 mm

changes:

• surface area: 185 → 86 m²/m³;
• packing factor: 216 → 97 m⁻¹;
• packing population: 75,000 → 9,772 pcs/m³. 

That is a major bed change.

Therefore:

same packed height should not automatically be retained without reviewing process duty.

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27. Support Grid Compatibility

Changing from:

80 mm → 16 mm

may make the existing support openings too large to retain the new packing.

The support should be checked for:

• retention opening;
• structural load;
• open area.

Packing size selection and tower-internals compatibility are linked.

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Metal Conjugated Ring Size Decision Table

This is a preliminary product-position table based on verified physical data—not guaranteed tower performance.

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28. Quick Selection Logic

Move toward 16 mm when:

• very high geometric area is required;
• service is clean;
• fine packing is hydraulically acceptable.

Move toward 25 mm when:

• high area is still important;
• but 16 mm creates too fine or heavy a bed.

Move toward 38 mm when:

• contacting and hydraulic openness need a stronger balance.

Move toward 50 mm when:

• lower packing factor and coarse bed geometry become stronger priorities.

Move toward 80 mm when:

• the tower is sufficiently large;
• very low packing population is specifically valuable;
• fouling or coarse-bed preference justifies it.

Do not choose 80 mm solely expecting a large additional packing-factor advantage over 50 mm.

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29. What Information Should Be Included in an RFQ?

Provide:

• Metal Conjugated Ring;
• preferred size if known;
• required metal grade;
• tower internal diameter;
• packed height;
• gas/vapor composition;
• liquid composition;
• gas/vapor flow;
• liquid flow;
• operating temperature;
• operating pressure;
• process duty;
• allowable pressure drop;
• fouling or solids conditions.

For replacement projects also provide:

• existing packing dimensions;
• thickness;
• alloy;
• support-grid details;
• reason for replacement.

Ask the supplier to confirm:

• exact dimensions;
• thickness;
• specific surface area;
• void fraction;
• bulk density;
• pieces per cubic meter;
• dry packing factor.

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Common Selection Mistakes

Assuming Void Fraction Always Increases with Size

It does not. The verified sequence is:

97% → 95% → 96% → 96% → 95%.

Selecting 16 mm Only for Its 313 m²/m³ Surface Area

It also has the highest packing factor, packing population and bed weight.

Selecting 80 mm Only Because It Is the Largest

Its packing factor is only slightly below the 50 mm value.

Assuming 80 mm Has Higher Void Fraction Than 50 mm

The catalog gives:

• 50 mm — 96%;
• 80 mm — 95%.

Assuming a Large Size Change Always Creates a Large Hydraulic Change

50 → 80 mm changes packing factor only from 97 to 95 m⁻¹.

Converting Packing Factor Directly into Pressure Drop

Operating conditions are still required.

Ignoring Packed-Bed Weight

The size difference can materially change support loading.

Changing Size Without Reviewing Bed Height and Support

Both process and mechanical conditions may change.

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Frequently Asked Questions

What Metal Conjugated Ring sizes does DAIER's catalog include?

The verified series includes approximately 16, 25, 38, 50 and 80 mm.

Which size has the highest surface area?

The 16 mm model at approximately 313 m²/m³.

Which size has the lowest packing factor?

The 80 mm model at approximately 95 m⁻¹, but this is only slightly below the 97 m⁻¹ of the 50 mm model.

Which size has the highest void fraction?

The 16 mm model at approximately 97% in this supplier-specific series.

What is the surface area of 25 mm?

Approximately 185 m²/m³.

What is the surface area of 38 mm?

Approximately 116 m²/m³.

What is the surface area of 50 mm?

Approximately 86 m²/m³.

What is the surface area of 80 mm?

Approximately 81 m²/m³.

Is 80 mm much more hydraulically open than 50 mm?

Not according to packing factor alone. The verified values are approximately 95 and 97 m⁻¹ respectively. The main difference is much lower packing population for 80 mm.

Which size is better for fouling service?

Larger sizes generally deserve stronger preliminary consideration because they create a much coarser bed, but severe fouling may require another packing geometry.

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Selection Takeaway

Metal Conjugated Ring size selection shows why “larger packing = higher voidage and much lower pressure drop” is too simplistic.

Across DAIER's verified series:

16 mm → 313 m²/m³ / 97% void / 354 kg/m³ / 211,250 pcs/m³ / 324 m⁻¹

38 mm → 116 m²/m³ / 96% void / 131 kg/m³ / 19,500 pcs/m³ / 131 m⁻¹

50 mm → 86 m²/m³ / 96% void / 97 kg/m³ / 9,772 pcs/m³ / 97 m⁻¹

80 mm → 81 m²/m³ / 95% void / 94.5 kg/m³ / 3,980 pcs/m³ / 95 m⁻¹.

The most important insight is the final transition:

50 → 80 mm dramatically reduces the number of packing elements, but hardly changes catalog packing factor and actually lowers published void fraction slightly.

Therefore:

80 mm should be selected because the process needs a very coarse large-element bed—not simply because the buyer assumes the largest size must provide dramatically lower hydraulic resistance.

The correct sequence is:

Process Duty → Gas/Liquid Loads → Contacting Requirement → Hydraulic Margin → Fouling → Tower Diameter → Exact Metal Conjugated Ring Size → Alloy → Support Grid Review