“How do I know if my sieves are in spec still?”
"How do I clean my sieves?"
If you use test sieves during your day, you may have asked yourself these questions before.
Test sieves are technical instruments used to separate particles. They are used all over the world, in every industry. They can be used for fine powders or abrasive materials in the agricultural or mining industries, for example. Regardless of what you are sieving, it is important to take proper care of your sieves. As a customer and user, you want to get the longest life out of your sieves. More importantly, if your sieve falls out of spec (gets clogged or damaged) you are not going to be meeting your quality standards. This can cost your company money and time, and nobody wants that.
We have written this article to help you better understand the things you can do to ensure the life of your sieve and make sure it stays in top condition. We will be covering cleaning, inspections, usage, storage, and certification in the next few sections.
1. Regular visual inspections
The first tip is to be sure you are doing regular visual inspections of your sieves. This is an easy way to be sure that your sieves haven't suffered any wear and tear recently that will alter the analysis.
It is recommended to do a visual inspection on a schedule that you determine based on your needs. Here are the things you should be looking for during a visual inspection:
Dents in the mesh
This should be one of the easier things to spot when looking at the sieve. By holding the sieve up to good light you should be able to see that the mesh is still pulled tightly across the entire surface.
If you see spots that look like they are dented, you will not want to continue to use this sieve in your process. Dents in the mesh can cause the openings in the mesh to stretch out or change size. This is going to impact the accuracy of your tests.
Scratches in the mesh
Just like with dents in the mesh, you should be visually inspecting your sieves to see if there are any scratches. The scratches can cause tears or rips in the mesh and this can alter your sieve analysis.
Cracks in the epoxy
The epoxy is the gray substance that is used to hold the mesh of the sieve onto the frame. It looks like clearrubber cement or glue. You should check the edges of the sieve, where the mesh meets the metal, and make sure there are no cracks in it. If this happens to your sieves, it can allow more particles to go through the sieve than are supposed to. This will skew your testing results.
2. Sieving Correctly
One of the best ways to keep your sieves in their top condition is to be sure you are using them correctly. It is not uncommon for to hear that sieves are being misused. There are a few ways you could be using your sieve incorrectly.
- Pushing particles through the sieve: If you are hand sieving, you should not be putting an excessive amount of pressure on the mesh in the sieve to push particles through.
- Placing too much of your sample or too many particles on the sieve at once: Doing this could cause blinding. Blinding occurs when the holes in the sieve get clogged up. This stops the particles from free flowing through the mesh and will skew results.
3. Cleaning your sieves
This may be the most important thing to know when it comes to using and maintaining your sieves. We are going to break cleaning down into five steps and then talk about what soap and utensils you should use.
Test sieves should be cleaned after each use to ensure that the next sample run through the sieve is done properly.
How to clean a sieve:
- Turn the test sieve over a receiving pan
- Gently brush the underside of the mesh using a circular motion
- Gently tap the sieve frame with the brush handle to remove any particles that may cling to the frame
- Wash sieves in warm water and a mild detergent solution
- Allow adequate time for the sieve to dry before using
Soap or cleaning solution
We recommend you use a mild cleaning solution. A dish detergent like Simple Green typically works well.
It may seem like you can grab any brush and scrub your sieve, but it is highly recommend that you don’t do this. It is important that you use a brush that is not going to be too hard on the wire mesh but that still gets the mesh clean. Be sure you are purchasing a brush that is specifically intended for use with sieve cleaning.
Sometimes with finer mesh sieves, it can be hard to get them clean because the openings are too small. If this might be the case for you, you can use an ultrasonic cleaner to clean your sieves. This machine is designed to vibrate and clean sieves that have small openings.
There are a few things you should not do when it comes to sieve cleaning:
- Do not use an oven to dry your sieves or a dishwasher to clean them; this can damage the sieve
- Do not use air pressure to clean your sieves; this can damage the mesh
- Do not force particles out of the openings with a brush or your hands when cleaning
- Do not use acidic solutions to clean the sieves
- Do not try to repair the sieve
4. Storing your sieves
This one is pretty simple: test sieves need to be stored in a clean, dry, and controlled environment.
In order to keep the sieve in its optimal condition, it cannot be stored in a wet place or in a rapid temperate changing environment. This could damage the sieve, especially the epoxy in the sieve, which could result in failed testing.
5. Recertifying your sieves
The best ways to ensure your test sieves are meeting your industry standards is to send your sieves in for recertification.
A test sieve certification is a statement or verification that a sieve meets or exceeds written standards. It is an assurance that a sieve was manufactured to (and performs to) a certain level of performance.
To certify a test sieve, the sieve is first examined visually to look for tears, wavy mesh, or cracked epoxy. Next, the sieve is scanned under a microscope that looks at a certain number of openings in the mesh to make sure they are not stretched or clogged, and verifies the wire diameter.
If the sieve meets the level of certification required, it passes and is provided back to you with a verification of the openings and other technical information. If the sieve does not pass, you will be informed and can purchase new sieves.
You can learn all about how certification works and how to know when you need to recertify your sieves in this article: what is test sieve certification?
Candace Blaker is W.S. Tyler particle analysis equipment manager. She spends most of her time working with lab managers to meet all of their analysis needs by providing testing equipment and support. With more than 15 years experience, Candace is an expert in all things test sieves, sieve shakers, and digital imaging analysis. Her focus is making sure her customers get the most out of their results and particle analysis equipment to meet their own industry and process requirements. She can be reached at: firstname.lastname@example.org.