How to Identify Existing Tower Packing from Photos and Dimensions
Existing tower packing can often be preliminarily identified from its geometry, dimensions, material, surface features and clear photographs—but a photo alone is not always enough to confirm an exact model or manufacturer.
This situation is common in maintenance and replacement projects.
A plant opens an old absorber, scrubber, stripper or distillation column and finds packing that may have been installed:
10 years ago;
20 years ago;
by another EPC;
by an unknown supplier;
without an available datasheet;
under an obsolete product designation.
The purchasing team then has a practical problem:
“We need replacement packing, but we do not know exactly what this packing is.”
The safest approach is not to guess from appearance.
Instead, identify the packing step by step using:
packing family → geometry → dimensions → material → physical characteristics → tower information → operating history.
This guide explains that process.
1. Can Tower Packing Really Be Identified from a Photo?
Often, the packing family can be identified from a good photograph.
For example, it may be possible to distinguish:
Pall Ring;
Raschig Ring;
saddle packing;
Cascade Mini Ring-type packing;
other high-performance random packing;
structured packing;
grid packing.
Major mass-transfer suppliers maintain clearly different packing geometries because geometry affects flow paths and tower performance. Sulzer, for example, distinguishes conventional R-Ring and P-Ring geometries, while Koch-Glitsch separately identifies conventional Pall-ring-type, IMTP-type and other random packing families.
But identifying the exact proprietary model from a photograph can be much more difficult.
Different manufacturers may produce products with:
similar shapes;
similar nominal sizes;
modified wall openings;
different thicknesses;
slightly different tabs;
different surface textures.
Therefore:
Photo identification should normally be treated as preliminary identification—not automatic final confirmation.
2. What Should You Photograph?
Do not send one distant photograph of a pile of packing.
For useful identification, photograph:
Individual Packing Element
Place one clean packing piece on a plain background.
Take:
front view;
side view;
top view;
bottom view;
angled view.
Packing With a Scale
Place the packing next to:
ruler;
caliper;
tape measure.
This allows the supplier to understand actual size.
Internal Structure
For ring-type packing, photograph the internal tabs, blades or fingers.
Surface
Show whether the packing has:
smooth surface;
perforations;
embossed surface;
mesh;
corrugation;
ceramic texture.
Damaged Packing
If the packing failed, photograph:
corrosion;
deformation;
breakage;
scaling;
plugging;
deposits.
These images may help explain why the packing needs replacement, not only what the packing is.
3. What Dimensions Should Be Measured?
For random packing, measure at least:
maximum outside diameter;
overall height;
wall thickness where practical.
Depending on geometry, also measure:
opening width;
internal tab dimensions;
ring height-to-diameter relationship;
saddle width;
saddle height.
Use a caliper where possible.
Do not rely only on statements such as:
“It looks like 50 mm.”
An actual measurement such as:
Outside diameter: approximately 50.5 mmHeight: approximately 50 mm
is much more useful.
4. Nominal Size Is Not Always the Exact Measured Size
A packing marketed as:
25 mm;
38 mm;
50 mm;
76 mm;
does not necessarily measure exactly that number in every direction.
Nominal packing size is a product designation.
Actual geometry can vary according to:
packing family;
manufacturer;
material;
tooling;
design generation.
Therefore, do not reject a preliminary identification simply because a “50 mm” packing measures slightly above or below exactly 50.0 mm.
Instead, compare the complete geometry.
5. How to Recognize a Raschig Ring
A traditional Raschig Ring is usually the easiest random packing to recognize.
Its basic form is:
a simple hollow cylindrical tube.
Typical visual characteristics include:
cylindrical shape;
open top and bottom;
relatively continuous wall;
no Pall-ring-style internal fingers;
simple geometry.
Sulzer identifies its R-Ring as the classic Raschig-ring geometry and separately describes the later P-Ring as a development based on the Raschig Ring.
If the removed packing looks like a simple short tube, Raschig Ring should be one of the first possibilities considered.
6. How to Recognize a Pall Ring
A Pall Ring also has a cylindrical form, but the wall is much more open.
Typical features include:
cylindrical outer shape;
multiple windows in the wall;
inward-projecting tabs or fingers;
open center;
internal structures formed from the wall.
Sulzer describes Pall-ring-equivalent P-Ring packing as having punched sections that leave windows in the outside wall, improving vapor flow compared with a Raschig Ring.
Koch-Glitsch similarly describes Pall-ring-type FLEXIRING® packing as an open cylindrical geometry that improves use of internal surface and lowers flow resistance compared with traditional Raschig Rings.
So a useful visual rule is:
simple solid cylinder → possibly Raschig Ring
open cylinder with internal tabs → possibly Pall Ring
For complete Pall Ring fundamentals, see:
What Is Pall Ring Packing and How Does It Work?
7. How to Recognize Saddle Packing
Saddle packing does not look like a cylinder.
Its main visual characteristic is:
a curved saddle-shaped element.
Depending on the specific design, the packing may have:
two opposing curves;
an open center;
curved edges;
ribs;
perforations;
textured surfaces.
Traditional saddle and later high-performance saddle geometries can look significantly different.
Therefore, identification should distinguish between:
general saddle-type packing
and
an exact proprietary saddle model.
If an exact historical model cannot be confirmed, the supplier can still use dimensions and process conditions to evaluate a technically suitable replacement.
For the basic saddle geometry, see:
What Is Intalox Saddle Packing?
8. Pall Ring vs Saddle: The Fastest Visual Difference
A simple first screening is:
Pall Ring
Looks primarily like an open cylinder.
Saddle
Looks primarily like a curved open saddle.
Both are random packing.
They are installed as many loose individual elements inside the tower.
However, they should not automatically be treated as hydraulically interchangeable.
For the detailed engineering comparison, see:
Pall Ring vs Intalox Saddle: Which Packing Is Better for Your Tower?
9. How to Recognize High-Performance Random Packing
Identification becomes harder with modern high-performance random packing.
These products may combine characteristics of:
rings;
saddles;
blades;
strips;
open cages.
For example, Koch-Glitsch describes IMTP® packing as combining characteristics of traditional saddle geometries with ring-style random packing performance.
Therefore, an unfamiliar metal packing with a very open irregular geometry should not immediately be labeled:
“Pall Ring.”
It may belong to a later high-performance packing family.
For these products, provide:
several photographs;
exact dimensions;
material;
approximate installation date;
any old tower drawings;
any visible markings.
10. Can the Exact Brand Be Identified?
Sometimes.
But not always.
Several packing designs have been widely copied, modified or manufactured in generic equivalents over decades.
Without:
original drawing;
packing datasheet;
supplier record;
purchase order;
identifying mark;
dimensional confirmation;
a photograph may identify the packing family but not prove the exact original manufacturer.
This distinction matters.
The engineering objective in a replacement project is often not:
“Who manufactured this piece 18 years ago?”
The more useful question may be:
“What packing characteristics must the replacement provide for this tower?”
11. How to Identify Plastic Packing
Plastic packing is generally relatively easy to distinguish visually and by weight.
Typical plastic random packing may be made from:
PP;
PE;
PVC;
CPVC;
PVDF;
specialty polymers.
However:
color alone cannot reliably identify the exact polymer.
Black, white, natural, grey or other colors can occur depending on:
resin;
additives;
production batch;
UV stabilizers;
supplier.
Do not state:
“It is black, so it must be PP.”
Material should be confirmed from:
original documentation;
material identification;
laboratory testing where necessary;
known plant specification.
12. Can You Distinguish PP from PVDF by Appearance?
Not reliably enough for a final procurement specification.
Two plastic packings can have similar:
color;
geometry;
surface appearance.
But their:
density;
chemical resistance;
temperature capability;
cost;
can be very different.
If the existing material is unknown and process chemistry is important, obtain a sample and verify the material rather than guessing.
This is particularly important before replacing a packing in:
strong acid service;
oxidizing environments;
solvent service;
elevated temperature.
13. How to Identify Metal Packing
Metal random packing is usually visually obvious as a material family.
But the alloy cannot be reliably determined from appearance.
A metal packing that looks like stainless steel might be:
SS304;
SS316;
SS316L;
duplex stainless;
another alloy.
Visual appearance cannot confirm alloy chemistry.
For a replacement project, use:
original material certificate;
PMI where appropriate;
laboratory analysis;
known original specification.
Do not specify SS316L simply because an old packing looks like stainless steel.
14. How to Identify Ceramic Packing
Ceramic packing generally has:
rigid ceramic body;
relatively thick walls compared with thin stamped metal packing;
hard brittle structure;
ceramic surface texture.
Common ceramic geometries include:
Raschig Ring;
Pall Ring;
saddle packing.
If the packing is ceramic, identification should not stop at:
“Ceramic Saddle.”
For a technical replacement, relevant information may also include:
ceramic composition;
acid resistance;
alkali resistance;
water absorption;
mechanical strength;
operating temperature.
The exact ceramic grade cannot normally be confirmed from a photograph.
15. How to Recognize Structured Packing
Structured packing looks fundamentally different from random packing.
Instead of thousands of loose individual pieces, structured packing is built from organized layers or blocks.
Common visual features include:
corrugated sheets;
repeated geometric channels;
alternating sheet orientation;
cylindrical or segmented blocks;
ordered structure.
Koch-Glitsch describes structured packing performance as arising from a regular geometric arrangement of corrugated sheets, while Sulzer likewise supplies structured packing as engineered geometric elements rather than loose random pieces.
If the tower contains stacked corrugated blocks rather than loose rings or saddles, it is likely structured packing.
16. What Should Be Measured on Structured Packing?
Structured packing requires more detailed measurement.
Record:
tower internal diameter;
packing block diameter or segment dimensions;
individual layer height;
total bed height;
corrugation height if practical;
corrugation angle;
sheet thickness where practical;
number of segments per layer;
number of layers.
Also photograph:
top surface;
side surface;
segment joints;
corrugation direction;
surface texture;
support arrangement.
These details help determine whether a replacement can fit the existing vessel and manway.
17. Why Is Manway Size Important?
Loose random packing can usually be loaded as individual pieces.
Structured packing and large tower internals are different.
Replacement components may need to pass through a limited manway.
Therefore, record:
manway diameter;
manway width and height;
access orientation;
internal obstructions.
DAIER's existing tower replacement guide specifically identifies manway and installation restrictions as important inputs because structured packing and large internals may require segmentation for installation.
A replacement packing cannot be correctly engineered if it physically cannot enter the tower.
18. Do Not Identify Packing from Shape Alone
For a stronger identification, combine several pieces of evidence.
Geometry
Ring, saddle, structured block, grid or another form.
Dimensions
Diameter, height, width, wall thickness.
Material
Plastic, metal or ceramic.
Weight
Individual piece weight or bulk weight if available.
Surface Features
Windows, tabs, ribs, perforations, corrugations.
Existing Documents
Old datasheets, drawings, POs, maintenance records.
Tower Service
Absorber, scrubber, distillation column, stripper.
Operating Conditions
Temperature, pressure, chemistry and flow.
Together, these create a much stronger identification than one photograph.
19. Bulk Density Can Help Confirm a Packing
If a sufficient quantity of old packing is available, approximate bulk density can provide another useful reference.
A basic method is:
fill a container of known volume with the packing in a representative loose arrangement;
determine the net packing weight;
divide packing weight by container volume.
This gives an approximate bulk density.
The result can then be compared with available supplier reference data.
However, bulk density can vary with:
packing geometry;
size;
material;
wall thickness;
how the sample is loaded.
It should therefore be used as supporting evidence, not as the only identification method.
20. The Existing Packing Condition Is Part of the Identification
Do not clean and discard all evidence before recording the packing condition.
Deposits or damage can reveal important information.
Check for:
Corrosion
May indicate unsuitable material or changed process chemistry.
Deformation
May indicate:
excessive temperature;
mechanical loading;
unsupported packing;
process upset.
Breakage
Especially important with ceramic packing.
Scaling
May indicate crystallization or solids deposition.
Plugging
May indicate that packing passages are too small for the fouling service—or that the actual problem is elsewhere in the process.
Uneven Deposits
May indicate liquid-distribution problems.
The reason for failure should influence the replacement decision.
21. Do Not Automatically Copy the Old Packing
Identifying the existing packing does not mean the new packing should automatically be identical.
First determine why the packing is being replaced.
Case A — Normal Maintenance
If the packing performed well for many years, like-for-like replacement may be reasonable.
Case B — Corrosion
The geometry may be acceptable, but material may need review.
Case C — High Pressure Drop
The issue may involve:
fouling;
gas rate;
liquid rate;
packing geometry;
packing size;
blocked support internals.
Case D — Low Capacity
A higher-capacity packing may deserve evaluation.
Case E — Repeated Plugging
A larger or more open geometry—or a change elsewhere in the process—may be necessary.
Sulzer notes that random packing is often attractive in fouling or corrosive systems partly because it can be comparatively easy to replace.
22. Same Size Does Not Mean Same Packing
A common replacement mistake is:
“The old packing is around 50 mm, so any 50 mm packing will work.”
This is unsafe.
Two nominally similar packings may differ in:
geometry;
open area;
surface area;
void fraction;
bulk density;
hydraulic resistance;
mechanical characteristics.
For example, a Pall Ring and Raschig Ring can have similar nominal dimensions but clearly different structures. Sulzer explicitly describes P-Ring geometry as an evolution of R-Ring geometry with open wall windows that alter vapor flow and capacity.
Therefore:
nominal size is one identification parameter—not proof of hydraulic equivalence.
23. What Photos Should Be Sent to a Supplier?
For the fastest preliminary review, send:
Photo 1
One complete packing element from the front.
Photo 2
Top view.
Photo 3
Side view.
Photo 4
Internal structure.
Photo 5
Packing next to ruler or caliper.
Photo 6
Several packing elements together.
Photo 7
Packing bed before removal, if available.
Photo 8
Support grid and distributor.
Photo 9
Deposits, corrosion or damage.
Photo 10
Tower manway.
This photo set is much more useful than sending only a picture of a bag or pile of packing.
24. What Measurements Should Be Written Next to the Photos?
For random packing:
diameter:
height:
width:
wall thickness:
approximate piece weight:
material if known:
For structured packing:
element height:
segment width:
segment length:
tower ID:
corrugation dimensions:
sheet thickness:
manway dimensions:
Use millimeters consistently where possible.
Do not expect the supplier to estimate critical dimensions from a photograph without a reference scale.
25. What Tower Information Should Be Included?
Once the packing has been preliminarily identified, provide:
tower internal diameter;
packing bed height;
number of beds;
current packing quantity;
support-grid information;
hold-down or bed limiter;
liquid distributor;
manway size.
For multiple beds, list each separately.
Example:
Tower ID: 1800 mmBed 1: 2500 mmBed 2: 3000 mmExisting packing: Unknown plastic open ring, approx. 50 mm
This immediately gives the replacement discussion more engineering context.
26. What Operating Information Should Be Included?
If the goal is only identifying the physical product, operating data may not always be necessary.
If the goal is deciding what replacement should be purchased, it becomes very important.
Provide:
gas flow;
liquid flow;
temperature;
pressure;
gas composition;
liquid composition;
solids;
fouling;
current pressure drop;
required performance.
DAIER's existing replacement workflow similarly emphasizes that replacement selection should use current operating conditions rather than relying only on the original packing specification.
27. How to Identify Packing When No Original Documents Exist
Use this sequence.
Step 1 — Determine the Packing Family
Random or structured?
Step 2 — Identify Basic Geometry
Ring, saddle, high-performance open shape, corrugated sheets or grid?
Step 3 — Measure the Element
Record accurate dimensions.
Step 4 — Identify Material Family
Plastic, metal or ceramic?
Step 5 — Search Historical Documentation
Check:
equipment file;
old PO;
EPC drawing;
maintenance report;
spare parts list.
Step 6 — Compare Physical Data
Where available, compare:
dimensions;
bulk density;
weight;
geometry.
Step 7 — Review Process Conditions
Determine whether the old packing is still technically appropriate.
Step 8 — Decide Replacement Objective
Like-for-like or upgrade?
This approach is more reliable than trying to recognize an old packing from one image.
28. When Should a Physical Sample Be Sent?
A physical sample becomes useful when:
exact geometry cannot be confirmed;
dimensions are unusual;
the packing appears proprietary;
material is uncertain;
replacement must closely match existing packing;
custom tooling may be required.
A sample allows the supplier to inspect:
shape;
dimensions;
wall thickness;
material characteristics;
manufacturing details.
For critical replacement projects, a physical sample can reduce uncertainty significantly.
29. Can an Obsolete Packing Be Replaced?
Often yes.
The replacement may be:
Exact Replacement
If the same model remains available.
Geometric Equivalent
If a similar product exists.
Engineered Replacement
If the original model is obsolete and another packing is selected based on:
process conditions;
hydraulics;
tower geometry;
material requirements.
The third case requires the most engineering review.
Do not assume an approximate visual match is an equivalent hydraulic replacement.
30. Replacement Packing Identification Checklist
Before requesting a replacement quotation, collect:
Packing
packing family;
photographs;
diameter;
height;
width;
wall thickness;
material;
approximate piece weight;
bulk density if available;
original model if known.
Tower
internal diameter;
packing bed height;
number of beds;
manway size;
support grid;
hold-down grid;
distributor.
Process
service;
gas flow;
liquid flow;
temperature;
pressure;
chemistry;
solids;
fouling.
Existing Problem
corrosion;
breakage;
plugging;
high pressure drop;
low efficiency;
insufficient capacity;
normal replacement.
Documents
old drawing;
old PO;
datasheet;
maintenance report;
process datasheet.
The more evidence is available, the lower the risk of ordering the wrong replacement packing.
Existing Tower Packing Identification FAQ
Can you identify Pall Ring from a photo?
Often the packing family can be recognized because Pall Rings normally have an open cylindrical wall with internal tabs.
Dimensions should still be supplied before final confirmation.
How can I tell a Pall Ring from a Raschig Ring?
A Raschig Ring is basically a simple hollow cylinder.
A Pall Ring has openings in the cylindrical wall and inward-projecting elements.
How can I tell a saddle from a Pall Ring?
A Pall Ring is primarily cylindrical.
Saddle packing has a curved saddle-shaped geometry.
Can a supplier identify the exact manufacturer from a photo?
Not always.
Several manufacturers may produce similar geometries, especially for conventional random packing.
Can plastic material be identified by color?
Not reliably enough for final procurement.
Material should be confirmed from documentation or testing when chemical compatibility is important.
Can SS304 and SS316L be identified visually?
No.
Alloy grade requires appropriate documentation or material verification.
Is the old packing size enough to select a replacement?
No.
Packing geometry, material, tower hydraulics and operating conditions should also be reviewed.
Do I need tower operating data if I only want the same packing?
For a simple like-for-like commercial replacement, complete process data may not always be required.
But operating data becomes important if the packing has failed, fouled, corroded or must provide improved performance.
Should I send a physical sample?
Yes when the packing cannot be confidently identified from photographs and measurements, or when exact replacement geometry is important.
Engineering Takeaway
Unknown existing tower packing should be identified from multiple pieces of evidence—not from one photograph or nominal dimension.
Use:
geometry + dimensions + material + surface features + weight + tower information + operating history.
A photograph may tell you that the packing is probably:
Pall Ring
or
Raschig Ring
or
saddle packing
or
structured packing.
But that does not automatically prove:
exact model;
exact manufacturer;
exact material;
hydraulic equivalence.
And identifying the old packing is only the first question.
The second question is more important:
Should the tower actually use the same packing again?
For a successful replacement project, first identify what is installed, then determine why it is being replaced, and only then finalize the new packing specification.
Need Help Identifying Existing Tower Packing?
Send DAIER:
clear packing photos · dimensions · material if known · tower ID · packing height · manway size · current operating problem
If the exact model cannot be confirmed, the existing packing can first be screened by geometry and dimensions before evaluating technically suitable replacement options.
For replacement projects, the DAIER Tower Packing Engineering Assistant can also help organize the existing tower and operating data before RFQ preparation.
Pingxiang Daier Separation Tech Co., Ltd.Random Packing · Structured Packing · Tower Internals · Mist Eliminators
Preliminary engineering support · Custom manufacturing · Factory reference data · Fast technical response
Specs and test data available upon request.