What Is Plastic Hiflow Ring Packing? Size Range, Applications and Selection Boundaries

Plastic Hiflow Ring packing is an open molded random packing designed to provide a practical balance between gas-liquid contacting area, hydraulic capacity, low packed-bed weight and corrosion resistance. Its engineering behavior changes significantly with nominal size, so Hiflow Ring should be treated as a multi-size product family rather than as one fixed-performance packing.

DAIER's catalog-confirmed engineering data includes 16, 25, 38, 50 and 90 mm Plastic Hiflow Ring models. Across this range, specific surface area decreases from about 260 m²/m³ for the 16 mm class to 73 m²/m³ for the 90 mm class, while void fraction increases from approximately 91% to 96%.

That creates a real engineering trade-off:

Smaller Hiflow Ring → more contacting areaLarger Hiflow Ring → greater hydraulic openness

The correct question is therefore:

Which Hiflow Ring size provides enough mass-transfer area without sacrificing the hydraulic and fouling margin required by the tower?

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1. What Is Plastic Hiflow Ring Packing?

Hiflow Ring belongs to the plastic random packing family.

Individual elements are randomly loaded into the packed bed.

Its molded open geometry is intended to provide:

• substantial void space;
• multiple gas-flow passages;
• liquid-contacting surfaces;
• good liquid drainage;
• relatively low bed weight.

It occupies the engineering space between very compact high-area random packing and extremely open low-area packing.

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2. Why Is the Size Range Important?

A Hiflow Ring specification should never stop at:

Plastic Hiflow Ring

because the nominal size strongly changes the packing characteristics.

DAIER engineering data contains the following catalog-confirmed product series:

These figures illustrate why different Hiflow Ring sizes should not be treated as interchangeable.

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3. 16 mm Hiflow Ring

The 16 mm class provides the highest specific surface area within this catalog series.

It may deserve consideration where:

• strong contacting intensity is required;
• the tower is relatively small;
• service is clean;
• gas and liquid loading are moderate.

But its smaller passages can also mean:

• greater hydraulic resistance;
• increased plugging sensitivity.

Therefore, 16 mm should not automatically be selected because it has the highest surface area.

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4. 25 mm Hiflow Ring

The 25 mm class still provides relatively high surface area while offering somewhat more bed openness.

It may be attractive where the project needs:

• substantial contacting area;
• moderate hydraulic capacity;
• a relatively small random packing element.

Its suitability still depends on:

• tower diameter;
• fouling;
• allowable pressure drop;
• required mass transfer.

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5. 38 mm Hiflow Ring

The 38 mm class begins to move more clearly toward a balanced industrial position.

Compared with smaller Hiflow Rings, it provides:

• lower surface-area density;
• greater void space;
• lower bulk density.

This may make it useful where both:

• mass transfer;
• hydraulic margin

carry meaningful weight.

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6. 50 mm Hiflow Ring

The 50 mm class places more emphasis on hydraulic openness.

It may deserve consideration for:

• absorbers;
• scrubbers;
• stripping towers

where:

• gas throughput is significant;
• fouling tolerance matters;
• pressure-drop control is important.

It provides less specific surface area than 16 or 25 mm models, so the separation requirement must still be satisfied.

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7. 90 mm Hiflow Ring

The 90 mm class is the most open of the catalog-confirmed sizes listed above.

Its data show approximately:

• 73 m²/m³ surface area;
• 96% void fraction;
• 33 kg/m³ bulk density. 

This makes it particularly interesting where:

• large flow passages;
• low packing weight;
• hydraulic openness;
• fouling tolerance

receive stronger priority than maximum surface-area density.

But 90 mm can be too large for smaller towers.

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8. Why Higher Void Fraction Matters

Void fraction indicates how much of the packed-bed volume remains open.

Greater open volume can support:

• gas passage;
• liquid drainage;
• hydraulic capacity.

But:

Void fraction is not the same as pressure drop.

Actual tower pressure drop depends on:

• gas flow;
• liquid flow;
• packing size;
• packed height;
• fluid properties.

A 96% void fraction should therefore not be converted into a universal low-pressure-drop guarantee.

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9. Why Surface Area Matters

Specific surface area provides an indication of the geometric surface available inside a unit packing volume.

Greater area can provide more opportunity for:

• liquid wetting;
• gas-liquid contact;
• mass transfer.

But increasing area usually changes the hydraulic structure of the bed.

The objective is therefore not:

Choose the highest m²/m³.

It is:

Choose enough contacting area while preserving required capacity and operating margin.

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10. Plastic Material Advantages

Plastic Hiflow Ring can provide:

• low dry bed weight;
• corrosion resistance in compatible service;
• economical molded construction;
• easier handling than heavy ceramic packing.

This can make it relevant to:

• FRP scrubbers;
• plastic absorbers;
• chemical gas-treatment towers.

However, the polymer must match the actual chemistry.

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11. Polymer Compatibility Still Requires Engineering Review

Plastic should not be selected from:

• pH;
• the word “acid”;
• the word “corrosive”

alone.

Compatibility depends on:

• chemical species;
• concentration;
• temperature;
• oxidizing environment;
• solvents;
• long-term exposure.

PP may be suitable in many services but should not be presented as universally resistant.

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12. Scrubber Applications

Plastic Hiflow Ring may be a useful candidate for gas scrubbers because the product family offers several sizes with different hydraulic and surface-area characteristics.

For example:

• smaller sizes may support greater contacting intensity;
• larger sizes may provide greater openness for high-flow or moderately fouling service.

This can make Hiflow Ring relevant to:

• chemical exhaust scrubbers;
• acid-gas treatment;
• odor control;
• industrial air-pollution equipment.

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13. Absorption Applications

In absorption towers, Hiflow Ring can provide gas-liquid contacting while maintaining significant open volume.

Selection should consider:

• absorption target;
• gas flow;
• liquid circulation;
• allowable pressure drop;
• required bed height.

A smaller Hiflow Ring may provide more contact area.

A larger size may be more suitable if the absorber is hydraulically constrained.

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14. Stripping Applications

Hiflow Ring can also be considered in compatible stripping systems.

The open random bed allows:

• upward gas or steam passage;
• downward liquid drainage.

The main selection variables include:

• required stripping performance;
• operating temperature;
• gas/liquid load;
• polymer compatibility.

If temperature exceeds practical polymer limits, metal or ceramic alternatives should be evaluated.

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15. Fouling Service

Packing size becomes especially important when fouling is expected.

Larger Hiflow Ring sizes provide larger passages that may offer greater tolerance for:

• moderate solids;
• biological growth;
• deposits.

But no Hiflow Ring should be described as:

non-clogging.

Severe:

• crystallization;
• scaling;
• sticky polymers

can eventually restrict even a large open packing bed.

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16. Hiflow Ring vs Plastic Pall Ring

Both are plastic random packing families.

Plastic Pall Ring

Offers:

• extensive industrial history;
• familiar ring geometry;
• broad procurement availability.

Plastic Hiflow Ring

Provides a distinct open molded geometry and a broad range from relatively high-area small sizes to very open large sizes.

Hiflow Ring may deserve stronger consideration when the project wants to tune:

surface area vs hydraulic openness

across several nominal sizes.

Pall Ring may remain preferable where:

• existing performance is proven;
• replacement compatibility matters;
• a conventional specification is preferred.

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17. Hiflow Ring vs Heilex Ring

Both can be used as open plastic random packing.

Heilex Ring places strong emphasis on:

• very open gas pathways;
• hydraulic operation.

Hiflow Ring provides a particularly clear size-dependent progression from:

• high-area 16/25 mm options

to:

• highly open 90 mm options.

Therefore, Hiflow Ring can be attractive where the project needs greater flexibility in balancing:

• mass transfer;
• hydraulic capacity.

The actual size and supplier data should determine the comparison.

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18. Hiflow Ring vs Ralu Ring

Both are multi-size plastic random packing families.

The correct comparison should not be:

Hiflow or Ralu—which is better?

Instead compare the actual candidate models for:

• specific surface area;
• void fraction;
• bulk density;
• nominal size;
• process requirement.

The engineering decision is made at the specific model level, not only at the product-family level.

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19. Hiflow Ring vs Snowflake Ring

Snowflake Ring places very strong emphasis on:

• large open passages;
• hydraulic robustness.

Smaller Hiflow Ring sizes provide much greater surface-area density than a highly open Snowflake-type product.

Therefore:

• Hiflow Ring may be more attractive where mass-transfer intensity still matters strongly;
• Snowflake Ring may be stronger where openness and fouling tolerance dominate.

The application determines the correct direction.

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20. Tower Diameter Matters

A large 90 mm packing should not automatically be used because the tower has high gas flow.

If the tower diameter is relatively small, oversized packing can create:

• stronger wall effects;
• poor bed uniformity;
• too few elements across the tower cross-section.

Likewise, using 16 mm packing in a very large fouling-prone tower can create unnecessary hydraulic restriction.

Packing size and tower diameter should always be reviewed together.

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21. Retrofit Applications

Hiflow Ring may be considered when an existing tower needs to address:

• high pressure drop;
• insufficient capacity;
• fouling;
• replacement of damaged packing.

But the replacement should review:

• current packing geometry;
• current packing size;
• tower ID;
• packed height;
• distributor;
• support grid;
• operating loads.

Changing from 25 mm Pall Rings to 50 mm Hiflow Rings, for example, is not merely a physical replacement.

It changes the packing characteristics.

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22. When Plastic Hiflow Ring Is a Strong Candidate

It deserves stronger consideration when:

• plastic is materially compatible;
• random packing is preferred;
• several size options are needed;
• gas capacity and mass transfer must be balanced;
• low bed weight is useful;
• scrubber or absorber service is involved.

The broad size range is one of the strongest reasons to treat Hiflow Ring as a meaningful engineering product family.

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23. When It May Not Be the Best Choice

Its priority should decrease when:

• very high temperature exceeds polymer capability;
• chemistry attacks the selected polymer;
• extremely high separation efficiency per unit height is required;
• severe fouling requires an even more open packing;
• demanding vacuum separation favors structured packing;
• an existing simpler packing already meets every process requirement.

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Hiflow Ring Size Selection Guide

This table is for preliminary product screening, not final hydraulic design.

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Common Selection Mistakes

Treating Hiflow Ring as One Fixed Product

The 16 mm and 90 mm models have very different engineering characteristics.

Selecting 16 mm Because It Has the Highest Surface Area

This can sacrifice hydraulic and fouling margin.

Selecting 90 mm Because It Has the Highest Void Fraction

This can reduce available contacting area and may be unsuitable for smaller towers.

Assuming Plastic Is Chemically Universal

Material compatibility must be checked separately.

Comparing Hiflow Ring and Pall Ring Without Matching Size

A meaningful comparison should use comparable candidate sizes.

Replacing Existing Packing by Equal Volume

Different packing sizes and geometries can change both hydraulics and mass transfer.

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Frequently Asked Questions

What is Plastic Hiflow Ring?

Plastic Hiflow Ring is an open random packing designed to balance gas-liquid contacting area with hydraulic capacity and low bed weight.

What sizes are available?

DAIER's catalog-confirmed data includes 16, 25, 38, 50 and 90 mm Hiflow Ring models.

Which Hiflow Ring size has the highest surface area?

Within the catalog-confirmed range above, the 16 mm model has the highest listed specific surface area at approximately 260 m²/m³.

Which Hiflow Ring size is most open?

Within the same dataset, the 90 mm model has the highest listed void fraction at approximately 96%.

Is smaller Hiflow Ring always better?

No. Smaller packing may provide more surface area but can also create greater hydraulic resistance and fouling sensitivity.

Is Hiflow Ring better than Pall Ring?

Not universally. Hiflow Ring offers a different geometry and size-dependent efficiency/capacity balance, while Pall Ring may be more suitable in other operating or procurement conditions.

Is Hiflow Ring suitable for fouling service?

Larger Hiflow Ring sizes may provide useful tolerance for moderate fouling, but severe solids, crystallization or sticky deposits still require additional review.

Can Hiflow Ring be used in FRP scrubbers?

It can be a strong candidate when the selected plastic material is compatible with the chemistry and operating temperature.

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Selection Takeaway

Plastic Hiflow Ring is best understood as a size-dependent random packing family rather than as one universal “high-flow” product.

Its catalog series illustrates the engineering trade-off clearly:

Smaller Size → Higher Surface AreaLarger Size → Higher Void Fraction and Lower Bed Weight

This makes Hiflow Ring useful when engineers need to deliberately balance:

Mass Transfer + Capacity + Fouling Tolerance + Pressure-Drop Margin

The correct selection sequence is:

Process Duty → Required Mass Transfer → Gas/Liquid Load → Fouling → Tower Diameter → Hiflow Size → Polymer Compatibility → Temperature

The key principle is:

Choose the Hiflow Ring size that matches the actual tower constraint—not simply the size with the highest surface area or the highest void fraction.