Metal Intalox Saddle Size Selection: 15 vs 25 vs 40 vs 50 vs 60 vs 70 mm

Metal Intalox Saddle size changes the balance between geometric surface area, free volume, packing population and hydraulic resistance. Across DAIER's catalog-confirmed 15–70 mm series, specific surface area decreases from approximately 275 to 61 m²/m³, while free volume increases from approximately 96.7% to 98.7% and dry packing factor decreases from 304.9 to 63.5 m⁻¹.

The verified series includes:

• 15 mm;
• 25 mm;
• 40 mm;
• 50 mm;
• 60 mm;
• 70 mm.

The primary selection trade-off is:

Smaller Metal Intalox Saddle → more geometric contacting area and a finer packed bed

while:

Larger Metal Intalox Saddle → higher free volume, fewer elements and lower packing factor.

The correct size is the one that provides enough mass-transfer opportunity without sacrificing the hydraulic margin required by the actual tower.

---

1. DAIER Metal Intalox Saddle Size Data

DAIER's product catalog identifies this family as Metal Intalox Saddle IMTP and provides the following physical data.

 

This is why a specification such as:

“Metal Intalox Saddle”

is incomplete unless the size is also defined.

---

2. What Changes as Size Increases?

The clearest trends are:

Surface area falls

From:

275 m²/m³ at 15 mm

to:

61 m²/m³ at 70 mm.

Free volume generally rises

From approximately:

96.7%

to:

98.7%.

Packing factor falls

From:

304.9 m⁻¹

to:

63.5 m⁻¹.

Packing population falls dramatically

From:

324,110

to:

4,690 pieces/m³.

So the 15 mm and 70 mm products create fundamentally different packed beds.

---

3. Why Surface Area Matters

Specific surface area describes the geometric packing surface available per cubic meter of bed.

Greater surface area can provide more potential locations for:

• liquid wetting;
• gas-liquid contact;
• vapor-liquid contact.

This makes smaller Metal Intalox Saddle sizes interesting where:

• contacting intensity matters;
• fluids are clean;
• hydraulic loads remain manageable.

However:

Geometric surface area is not the same as effective mass-transfer area.

Effective area depends on:

• wetting;
• liquid distribution;
• gas and liquid load;
• fluid properties.

Therefore the 15 mm model should not automatically be selected just because it has the highest catalog surface area.

---

4. Why Free Volume Matters

The verified free-volume data are:

• 15 mm — 96.7%;
• 25 mm — 96.6%;
• 40 mm — 97.4%;
• 50 mm — 97.9%;
• 60 mm — 98.2%;
• 70 mm — 98.7%. 

The broad trend favors larger sizes.

Higher free volume provides more physical space for:

• gas or vapor flow;
• liquid drainage;
• counter-current operation.

But notice:

25 mm has slightly lower free volume than 15 mm.

So even here, the progression is not perfectly monotonic.

Actual product geometry matters.

---

5. Why Packing Factor Matters

The dry packing factor decreases across the full series:

 

This provides a clear preliminary hydraulic direction:

Increasing size moves the Metal Intalox Saddle bed toward lower geometric resistance.

But packing factor alone does not calculate actual:

• pressure drop;
• flooding velocity;
• capacity.

Those require real process data.

---

6. 15 mm Metal Intalox Saddle

The 15 mm model provides:

• 275 m²/m³ surface area;
• 96.7% free volume;
• 263 kg/m³ bulk density;
• 324,110 pcs/m³;
• 304.9 m⁻¹ packing factor. 

This places it at the:

high-area / fine-bed

end of the family.

Stronger Preliminary Position

15 mm may deserve consideration where:

• high contacting-area density is important;
• process fluids are clean;
• column diameter is relatively small;
• pressure-drop margin is sufficient.

Main Boundaries

It deserves caution with:

• fouling;
• crystallization;
• solids;
• high gas or vapor throughput.

---

7. 25 mm Metal Intalox Saddle

The 25 mm model provides:

• 199 m²/m³ surface area;
• 96.6% free volume;
• 266 kg/m³ bulk density;
• 127,180 pcs/m³;
• 221.0 m⁻¹ packing factor. 

Compared with 15 mm:

• surface area decreases;
• packing population drops strongly;
• packing factor decreases.

But there is an interesting detail:

bulk density rises slightly from 263 to 266 kg/m³.

Therefore:

larger size does not automatically mean a lighter packed bed.

The increase in element thickness from approximately 0.3 to 0.4 mm helps explain why simple size trends should not replace actual catalog data.

---

8. Why 15 vs 25 mm Is Not a Simple Efficiency Choice

Moving from 15 to 25 mm changes:

Surface Area

275 → 199 m²/m³

Packing Factor

304.9 → 221.0 m⁻¹

Packing Population

324,110 → 127,180 pcs/m³.

The 15 mm model provides more geometric area.

The 25 mm model creates a less fine bed.

So the choice is really:

more contact-area density

versus:

greater hydraulic margin.

---

9. 40 mm Metal Intalox Saddle

The catalog's nominal 40 mm class uses an actual listed dimension of approximately:

35.4 × 18.8 × 0.4 mm.

Its properties are:

• 151 m²/m³ surface area;
• 97.4% free volume;
• 203 kg/m³ bulk density;
• 51,180 pcs/m³;
• 163.2 m⁻¹ packing factor.

This gives 40 mm a useful intermediate position.

It retains significant geometric area while creating substantially more open hydraulic characteristics than 15–25 mm packing.

---

10. Why 40 mm Can Be a Balanced Model

Compared with 25 mm:

• surface area falls from 199 to 151 m²/m³;
• free volume rises from 96.6% to 97.4%;
• packing factor falls from 221.0 to 163.2 m⁻¹;
• bulk density falls from 266 to 203 kg/m³. 

This gives 40 mm a strong:

contacting-area / hydraulic-openness compromise

for suitable industrial duties.

It should not automatically be called the “best” size, but its position between the extremes is technically meaningful.

---

11. 50 mm Metal Intalox Saddle

The 50 mm model provides:

• 97 m²/m³ surface area;
• 97.9% free volume;
• 169 kg/m³ bulk density;
• 15,550 pcs/m³;
• 103.9 m⁻¹ packing factor. 

This is a major transition.

Compared with 40 mm:

surface area falls from 151 to 97 m²/m³

while packing factor falls from:

163.2 to 103.9 m⁻¹.

This moves 50 mm clearly toward a more hydraulically open operating position.

---

12. 60 mm Metal Intalox Saddle

The 60 mm class uses a listed actual dimension of:

67 × 37 × 0.5 mm.

Its properties include:

• 84 m²/m³ surface area;
• 98.2% free volume;
• 145 kg/m³ bulk density;
• 9,000 pcs/m³;
• 88.4 m⁻¹ packing factor.

This size may become more attractive as the project increasingly prioritizes:

• gas or vapor throughput;
• hydraulic openness;
• lower packed-bed weight.

---

13. 70 mm Metal Intalox Saddle

The largest verified class is nominally 70 mm, with a listed actual element dimension of approximately:

76.5 × 42.5 × 0.5 mm.

Its data are:

• 61 m²/m³ surface area;
• 98.7% free volume;
• 106 kg/m³ bulk density;
• 4,690 pcs/m³;
• 63.5 m⁻¹ packing factor.

This places it firmly toward:

high hydraulic openness / low geometric area density.

It may deserve stronger consideration where:

• tower diameter is large;
• gas or vapor capacity matters;
• fouling tolerance is important;
• lower surface-area density remains acceptable.

---

14. Surface Area Ranking

The verified ranking is:

1. 15 mm — 275 m²/m³
2. 25 mm — 199 m²/m³
3. 40 mm — 151 m²/m³
4. 50 mm — 97 m²/m³
5. 60 mm — 84 m²/m³
6. 70 mm — 61 m²/m³. 

This is a clean downward trend.

If geometric contacting area is the dominant preliminary criterion:

smaller sizes move higher.

But actual tower performance still depends on hydraulic feasibility.

---

15. Free Volume Ranking

The broad trend moves upward:

• 15 mm — 96.7%;
• 25 mm — 96.6%;
• 40 mm — 97.4%;
• 50 mm — 97.9%;
• 60 mm — 98.2%;
• 70 mm — 98.7%. 

The important exception is:

25 mm is slightly lower than 15 mm.

That difference is small, but technically useful because it proves:

nominal size alone does not determine every physical property.

---

16. Bulk Density Is Also a Selection Variable

The verified bulk densities are:

• 15 mm — 263 kg/m³;
• 25 mm — 266 kg/m³;
• 40 mm — 203 kg/m³;
• 50 mm — 169 kg/m³;
• 60 mm — 145 kg/m³;
• 70 mm — 106 kg/m³. 

From 25 mm onward, bed weight falls strongly.

This matters for:

• packing supports;
• large packed volumes;
• transportation;
• tower revamps.

But the 15-to-25 mm anomaly means engineers should use actual data rather than an assumed density formula.

---

17. Packing Population Changes Dramatically

The bed contains approximately:

• 324,110 pcs/m³ at 15 mm;
• 127,180 at 25 mm;
• 51,180 at 40 mm;
• 15,550 at 50 mm;
• 9,000 at 60 mm;
• 4,690 at 70 mm. 

That changes:

• element-to-element contacts;
• characteristic void size;
• deposition behavior;
• bed structure.

This is one reason changing size should not be treated as a minor procurement substitution.

---

18. Size Selection for Clean Mass-Transfer Duty

In clean service where contacting intensity is important, preliminary selection may move toward:

15–25 mm

when:

• high geometric area matters;
• fouling risk is low;
• hydraulic load remains manageable.

40 mm

when:

• a stronger balance of area and openness is desired.

50–70 mm

when:

• hydraulic capacity increasingly dominates.

This is preliminary positioning—not a guaranteed model recommendation.

---

19. Size Selection for High Gas or Vapor Throughput

As gas or vapor load rises, higher free volume and lower packing factor become more important.

That can move the preliminary decision toward:

• 50 mm;
• 60 mm;
• 70 mm.

For example, dry packing factor decreases from:

304.9 m⁻¹ at 15 mm

to:

63.5 m⁻¹ at 70 mm.

However:

the tower still needs enough mass-transfer area to achieve the required duty.

The most hydraulically open option is not automatically the best process option.

---

20. Size Selection for Fouling Service

Fouling generally shifts preference away from the finest packing.

Smaller sizes create:

• more individual packing pieces;
• more contact points;
• finer local flow paths.

Larger sizes provide:

• fewer packing elements;
• larger characteristic openings;
• lower packing factor.

Therefore moderate fouling often moves preliminary screening toward:

• 50;
• 60;
• 70 mm.

Severe fouling may require another packing geometry entirely.

---

21. Crystallization Is a Strong Boundary

Crystals can form on:

• saddle surfaces;
• element contact points;
• local liquid paths.

A fine bed with hundreds of thousands of packing pieces per cubic meter can become increasingly sensitive to deposit bridging.

Therefore:

15–25 mm should not be selected from surface area alone when crystallization is significant.

The project may need:

• a larger saddle;
• a more open packing;
• another tower strategy.

---

22. Tower Diameter Must Match the Saddle Size

Large packing requires enough elements across the vessel cross-section.

If the 60 or 70 mm class is installed in a relatively narrow column:

• wall effects may increase;
• too few elements span the tower;
• bed uniformity may deteriorate.

The opposite also applies.

Installing very fine 15 mm packing in a large tower can create:

• excessive element count;
• unnecessary hydraulic resistance.

Packing size should therefore be checked against:

tower internal diameter.

---

23. Metal Intalox Saddle for Absorption

Metal Intalox Saddle can be considered in suitable absorption towers where:

• metal construction is chemically compatible;
• random packing is appropriate;
• saddle geometry provides useful liquid spreading.

Smaller sizes can provide more geometric area.

Larger sizes provide more hydraulic margin.

Absorption selection should consider:

• gas flow;
• liquid rate;
• process chemistry;
• required removal;
• packed height.

---

24. Metal Intalox Saddle for Stripping

Stripping duties may place substantial emphasis on:

• gas or vapor throughput;
• liquid drainage.

This can make intermediate or larger saddle sizes attractive.

But stripping performance still requires sufficient gas-liquid contact.

Therefore:

low packing factor should not be optimized independently from required mass transfer.

---

25. Metal Intalox Saddle for Distillation

Metal saddle packing may also be considered for suitable distillation duties.

Smaller packing can provide greater geometric contact density.

But highly demanding:

• vacuum distillation;
• high-purity separation;
• very-low-pressure-drop duties

may favor structured packing instead.

Metal Intalox Saddle should therefore be evaluated as one candidate rather than treated as the default for every distillation column.

---

26. Metal Grade Is a Separate Selection Layer

Size determines:

• geometry;
• hydraulic position;
• surface-area density.

Metal grade determines:

• corrosion compatibility.

Possible project materials may include:

• SS304;
• SS316L;
• other workable alloys. 

The correct alloy depends on:

• process chemistry;
• concentration;
• temperature;
• chlorides;
• corrosion mechanism.

A correctly sized saddle made from an incompatible alloy is still the wrong packing.

---

27. Why Alloy Selection Should Not Be Hidden Inside the Size Decision

A project may require:

25 mm SS316L

while another uses:

50 mm SS304.

That does not mean SS316L belongs to smaller packing or SS304 to larger packing.

These are independent decisions:

Material → corrosion compatibility

Size → hydraulics and contacting

Keep them separate in both engineering review and RFQ preparation.

---

28. Existing-Tower Replacement

For a replacement project, identify:

• existing packing type;
• actual dimensions;
• packing size;
• metal grade;
• bed height;
• tower diameter;
• support grid.

Changing:

25 mm → 50 mm

changes surface area from:

199 to 97 m²/m³

and packing factor from:

221.0 to 103.9 m⁻¹.

That is an engineering retrofit—not a simple like-for-like replacement.

---

29. Packing Height May Need Re-Evaluation

A larger saddle can improve hydraulic openness but reduce geometric surface-area density.

Therefore:

same tower + same bed height + larger packing

does not guarantee:

same process performance.

If size changes significantly, review:

• required packed height;
• hydraulic loading;
• process duty.

Do not assume the existing bed height remains automatically valid.

---

30. Support Grid Compatibility

The support grid must:

• retain the selected saddle;
• carry the packed-bed load;
• provide adequate open area.

Changing from:

70 mm → 15 mm

can create a retention problem if the existing support openings are too large.

A major packing-size change should always include:

support-grid review.

---

Metal Intalox Saddle Size Decision Table

This is preliminary positioning based on DAIER's catalog-confirmed product geometry, not guaranteed tower performance.

---

31. Quick Selection Logic

Move toward 15–25 mm when:

• service is clean;
• high geometric area is important;
• hydraulic load is manageable.

Move toward 40 mm when:

• contact and hydraulic openness need a stronger balance.

Move toward 50 mm when:

• gas/vapor throughput matters more;
• moderate fouling exists;
• lower packing factor is desired.

Move toward 60–70 mm when:

• hydraulic openness is strongly prioritized;
• tower diameter is sufficiently large;
• lower surface-area density remains acceptable.

---

32. What Information Should Be Included in an RFQ?

Provide:

• Metal Intalox Saddle / IMTP requirement;
• preferred size if known;
• metal grade;
• tower ID;
• packed height;
• gas/vapor composition;
• liquid composition;
• gas/vapor flow;
• liquid flow;
• operating temperature;
• operating pressure;
• required process duty;
• allowable pressure drop;
• fouling or crystallization information.

For replacements, also provide:

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

Ask the supplier to confirm:

• actual element dimensions;
• material thickness;
• surface area;
• free volume;
• bulk density;
• packing count;
• dry packing factor.

---

Common Selection Mistakes

Choosing 15 mm Only Because It Has the Highest Surface Area

It also has the highest packing factor and more than 324,000 pieces/m³.

Choosing 70 mm Only Because It Has the Lowest Packing Factor

Its surface area is only approximately 61 m²/m³.

Assuming Free Volume Increases Perfectly with Size

25 mm is listed at 96.6%, slightly below the 96.7% of 15 mm.

Assuming Larger Packing Is Always Lighter

25 mm is slightly heavier per packed cubic meter than 15 mm in this verified series.

Treating “IMTP” as Enough Information for Procurement

Exact size, geometry and supplier data should still be confirmed.

Ignoring Tower Diameter

Large saddle packing requires sufficient vessel diameter.

Changing Size Without Reviewing Bed Height

Hydraulic and mass-transfer behavior both change.

Ignoring the Support Grid

A support designed for large saddles may not retain smaller replacements.

---

Frequently Asked Questions

What Metal Intalox Saddle sizes does DAIER's catalog contain?

DAIER's current catalog-confirmed series includes approximately 15, 25, 40, 50, 60 and 70 mm classes.

Is Metal Intalox Saddle the same as IMTP?

DAIER's catalog labels this product family Metal Intalox Saddle IMTP. Product naming can vary between suppliers, so the actual geometry and physical specifications should be confirmed rather than relying on the commercial name alone.

Which size has the highest surface area?

The 15 mm class, at approximately 275 m²/m³.

Which size has the highest free volume?

The 70 mm class, at approximately 98.7%.

Which size has the lowest packing factor?

The 70 mm class, at approximately 63.5 m⁻¹.

What is the surface area of 25 mm Metal Intalox Saddle?

Approximately 199 m²/m³.

What is the surface area of 40 mm?

Approximately 151 m²/m³.

What is the surface area of 50 mm?

Approximately 97 m²/m³.

Is smaller Metal Intalox Saddle always better for mass transfer?

No. Smaller packing provides greater geometric surface area but creates a finer bed with higher packing factor.

Which size is better for fouling service?

Larger sizes generally deserve stronger preliminary consideration as fouling increases, but severe fouling or crystallization may require another packing geometry.

---

Selection Takeaway

Metal Intalox Saddle size selection is a direct trade-off between contacting-area density and hydraulic openness.

Across DAIER's catalog-confirmed series:

15 mm → 275 m²/m³ surface area / 96.7% free volume / 324,110 pcs/m³ / 304.9 m⁻¹ packing factor

while:

70 mm → 61 m²/m³ surface area / 98.7% free volume / 4,690 pcs/m³ / 63.5 m⁻¹ packing factor.

The broad selection direction is:

Clean, contact-intensive service → smaller size

while:

higher throughput, greater hydraulic margin or fouling concern → larger size.

But final selection must also consider:

• tower diameter;
• actual gas and liquid loads;
• required mass transfer;
• bed height;
• metal grade;
• fouling;
• support-grid compatibility.

The key principle is:

Select Metal Intalox Saddle size from the actual process and supplier-specific physical data—not simply from the assumption that smaller is more efficient or larger is always better hydraulically.