Ronnie Brown

By: Ronnie Brown on January 25th, 2022

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Bubble Point Test vs Glass Bead Test: Which Is Right for Me?

Wire Mesh | Filtration

From oil and gas sand separators used to filter unwanted sediments from raw oil to nutsche filters used to extract filter cakes from chemical solutions, wire mesh is a versatile product with endless possibilities. But with the market flooded with so many selections and specifications, it's essential to keep in mind that your wire mesh is only as reliable as its accuracy.

Seeking peace of mind, manufacturing engineers often subject potential mesh specifications to either a glass bead test or bubble point test. At first glance, these testing methods may seem interchangeable; however, the information they provide is substantially different.

This is why it's important to know how these integrity testing methods compare.

With over 150 years of experience helping customers integrate accurate and reliable wire mesh, W.S. Tyler understands that achieving the results you want requires mesh specifications that are fine-tuned to the exact needs of your process.

To help paint a better picture of how glass bead testing and bubble point testing compare and contrast, the following article will cover:

  • What a glass bead test is
  • What a bubble point test is
  • The differences between the two testing methods
  • The testing method that may be right for you


What Is a Bubble Point Test?


Bubble point testing is a wire mesh integrity testing method that submerges a tensioned wire mesh sample into a wetting agent and subjects it to calculated pressure. This pressure is applied until bubbles begin to protrude out of the pore openings of the mesh, establishing the maximum capillary pressure.


For a more in-depth breakdown of bubble point testing, read the following article:


What Is a Glass Bead Test?


Glass bead testing is the process in which glass microspheres are passed through wire mesh filter samples to identify the mesh's cut point and nominal speciation. To ensure effectiveness, NIST (National Institute of Standards and Technology) electroformed test sieves, as well as image analysis techniques, are applied to verify that each glass bead is within spec.


For a more in-depth breakdown of glass bead testing, read the following article:


How Do Bubble Point Tests and Glass Bead Tests Compare?

The differences you will encounter when comparing a glass bead test to a bubble point test come down to two categories: how the test is conducted and what your results say about the wire mesh.


Bubble Point Test

Like a glass bead test, an effective bubble point test starts with a sample of the wire mesh specification you intend to implement. Instead of being fitted into a test sieve; however, bubble point testing requires the wire mesh to be brought into tension.

The mesh is submerged into a wetting agent until each pore opening is filled.

Pressure is then applied to the mesh until bubbles form and pass through the mesh. To ensure accurate readings are achieved, factors, including the gas pressure, depth of mesh immersion, gas cleanliness, mesh cleanliness, liquid temperature, and liquid gravity, are regulated throughout the entire testing process.

A specialized, calibrated measuring tool reads and records the minimal pressure needed to form and project the bubbles.

Now, different wire mesh specifications and weave patterns are known to deliver variating performance qualities, particularly flow rate and cut point. Bubble point tests can help identify the maximum pore diameter and scrutinize the performance of a given wire mesh specification, especially when using complex weave types, which certain industries and applications require.


Glass Bead Test

A successful glass bead test involves first mounting a sample of the wire mesh to be tested to a test sieve frame. The sieve is loaded with the certified glass beads, which are collectively weighed before testing, and inserted into a sieve shaker, air jet sieve, or sonic sifter to facilitate particle agitation.

An end of sieve analysis is then used to calculate the amount of time the glass beads will need to be agitated on the test sieve. At this point, the glass beads are run, with the beads retained on the sieve being reweighed.

As wire mesh is used for screening and filtration applications, glass bead testing is critical as it will reveal the largest particle size that will pass through a particular mesh specification. This, in turn, provides insight into how the mesh will perform after a filter cake is accumulated on the mesh.

Free educational guide to industrial woven wire mesh

What Testing Method Should I Use?

Both glass bead and bubble point tests can be used to fine-tune your filtration system. But just like hand-selecting each wire mesh specification, the testing method you should implement depends on the outcome you want.

For example, glass bead testing can prove to deliver tremendous benefits when applying wire mesh to applications that form filter cakes, such as pharmaceutical production. This is because glass bead testing provides insight into the particle sizes that will be successfully screened.

On the other hand, a bubble point may be more beneficial than a glass bead test for plastic extrusion operations. This is because not only does a successfully conducting bubble point test indicate the amount of pressure your filtration system will need to apply to the mesh, but it also gives substantial indication as to the overall throughput you can expect.

To that end, a good rule of thumb to follow is if the main priority of your wire mesh is controlling the level of particle passage, a glass bead test will work best; however, if you want to ensure your wire mesh allots a specific balance of throughput and cut point, bubble point test will work best.


Create the Ultimate Wire Mesh Component With Virtual Mesh Design

Glass bead tests and bubble point tests are both methods used to determine the integrity of wire mesh. Glass bead testing can help identify the range of particles that will effectively be screened by the mesh. In contrast, bubble point testing can inform you of the pressure needed to project material through the mesh as well as the throughput allowed by the mesh.

But if you are looking into testing the integrity of your mesh, odds are you are still in the planning stages of the wire mesh component design process. As the findings provided by glass bead testing and bubble point testing are only the tip of the iceberg, you should also consider virtual mesh design to receive further details about how you can expect a particular mesh specification to perform.

Here at W.S. Tyler, woven wire mesh is simply our bread and butter. This is why we take pride in helping manufacturing engineers design the perfect wire mesh component piece by piece.

And with that, the following article will provide an in-depth breakdown of what virtual mesh design is and how it can help you determine whether or not wire mesh is feasible for your operation:

About Ronnie Brown

Ronnie is the Content Writer for W.S. Tyler and has four years of experience as a professional writer. He strives to expand his knowledge on all things particle analysis and woven wire mesh to leverage his exceptional writing and graphic design skills, creating a one-of-a-kind experience for customers.