Ronnie Brown

By: Ronnie Brown on February 25th, 2022

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RO-TAP RX-812 vs RO-TAP RX-94: What Makes Sense for Me?

Ro-Tap Sieve Shakers

Achieving accurate and repeatable test sieve analysis results starts with the right equipment. From the sieve shaker to the test sieves to the ancillary accessories, it's vital that you design a tailored experience.

So, are you invested in the right sieve shaker? With so many options, such as the W.S. Tyler RO-TAP® RX-812 and RO-TAP RX-94, this can prove to be a daunting question to answer.

As the creator of the RO-TAP product line, W.S. Tyler knows the ins and outs of the mechanical sieve shaker market and is here to ensure you furnish your lab with particle analysis equipment that makes sense.

And with that, this article was designed to highlight the differences between the RO-TAP RX-812 and the RO-TAP RX-94. We will discuss:

  • What the RO-TAP RX-812 is
  • What the RO-TAP RX-94 is
  • How the two devices compare
  • Which device is suitable for you


What Is the RO-TAP RX-812?


W.S. Tyler's RO-TAP RX-812 is a singular motion mechanical sieve shaker that uses oscillating pivots to agitate sample material in a test sieve stack. Unlike traditional sieve shakers, such as the W.S. Tyler RO-TAP RX-29, this device lacks brute force hammer taps.

This means the oscillating motion is the only thing that helps the particles find and pass through the openings of the sieve cloth.


What Is the RO-TAP RX-94?


Much like the RO-TAP RX-29, the RO-TAP RX-94 pairs brute force hammer taps with oscillating pivots to agitate sample material throughout a test sieve stack. The key feature of this device, however, is that it can test two test sieve stacks simultaneously.


How Do the RX-812 and RX-94 Compare?

Picking the right sieve shaker is an integral step to achieving accurate and reputable test sieve analysis results. To fully understand whether the RX-812 or the RX-94 will perform best for you, there are a few factors that should be considered.

These factors include:

  • Test sieve compatibility
  • Cost
  • Noise level
  • Installation
  • Ease of use
  • Maintenance


Test Sieve Compatibility


The RO-TAP RX-812 is called the 812 because it has the ability to house both 8- and 12-inch test sieves. That said, special inserts must be employed to ensure your specific test sieve diameter fits properly.



The RO-TAP RX-94 can only hold test sieves with an 8-inch diameter. Additionally, while two test sieve stacks can be tested at once, both must be the same height for the device to function properly.

When using full-height test sieves, the stack can consist of up to six test sieves with a collection pan. If half-height test sieves are used, the sieve stack can consist of up to 13 sieves and a collection pan.

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The RO-TAP RX-812 is accompanied by a price tag of approximately $1,731.99. The material cost influences this price; thus, it is subject to change.



The RO-TAP RX-94 runs at about $5,462.73. Again, this price is a direct reflection of the materials used to fabricate the device and is subject to change depending on the market.


Noise Level


One of the key selling points of the RX-812 is that it is one of the quietest mechanical sieve shakers on the market. This is mainly due to the absence of the hammer taps seen with the RX-94 and other mechanical sieve shakers.



As the RX-94 uses an identical hammer tap to promote particle movement within a test sieve stack as the RX-94, the devices have similar standalone decimal projections.

But because the RX-94 is designed to test two test sieve stacks simultaneously, the RX-94 is lounder when testing material. This is because the noise being produced from particles rattling in the test sieves is doubled.




The RO-TAP RX-812 is as easy to install as it is to use. The device is relatively heavy, so you will want to make sure at least two people work together when moving it from the box to its designated testing area.

To that end, you will want to place and bolt the device onto a sturdy area or a flat surface on the ground away from anything that can potentially fall onto it. Once secured, simply plug the device in and begin prepping for your test sieve analysis.



Installing the RX-94 is reasonably identical to the process used to install the RX-812. As it is notably one of the heavier sieve shakers offered by W.S. Tyler, it is typically placed and secured onto a designated area on the lab floor.

As with most mechanical sieve shakers, the RX-94 is known to shift and move around during operation, despite being so heavy. This is why it is critical to bolt the device down.

Some operators even place a rubber mat beneath the device for added grip and support.




To properly operate the RX-812, you will first want to conduct an end of sieve analysis if you have never used the device before.

Once you have determined how long to run your material, simply assemble and insert your test sieve stack, adjust the height of your sieve stack, set the testing time on the digital timer, and press start.



When using the RX-94, again, you will want to make sure you employ an end of sieving analysis to calculate how long your material should be tested. You can then insert your sieve stack into the device, adjust the sieve stack height, set the test durations, and press start.

With the RX-94 specifically, it is important to remember that you must use two test sieve stacks of the same height. The device will not function properly if one sieve stack is used or the sieve stacks don't have an equivalent height.

This is because the sieve cover must be level to create a complete seal.




As the RO-TAP RX-812 relies on the singular oscillating motion, it has a limited amount of moving parts. In turn, maintenance is a lot easier than other mechanical sieve shakers.

To that end, the device does still use a timing belt but doesn't require a lift rod to raise the hammer. This makes for seamless maintenance.



Like most aspects of the RX-94, its maintenance process is relatively similar to the RX-29. It is critical that you follow a regular maintenance schedule to ensure all moving parts are in tip-top shape.

This means you must be mindful of the state of the timing belt, bushings, and bearings.

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Which RO-TAP Is Right for Me?

The RO-TAP device you should use, whether it's the RX-812 or RX-94, depends on your particular needs. But more specifically, the material you will be testing and the size of your test sieves.

If your sample material consists of particles 100 mesh and larger, the RX-812 may better suit your needs. This is because it is designed to test coarser material much quieter than the RX-94.

Additionally, as the RX-812 can test both 8-inch and 12-inch test sieves, if you are required to use 12-inch sieves, the RX-812 is your only option between the two devices.

On the other hand, if you are testing material finer than 100 mesh down to 200 mesh, the RX-94 will be the better solution. Once you reach 200 mesh, testing may take longer than usual as the force from the single hammer tap is distributed across the two sieve stacks.

To that end, if you are testing material finer than 200 mesh, an additional end of sieving analysis should be conducted.


Are Sieve Shakers Right for You?

The W.S.Tyler RO-TAP RX-812 and RX-94 are mechanical sieve shakers designed to generate an accurate particle size distribution curve. The RX-812 uses a singular oscillating motion to agitate both 8-inch and 12-inch test sieve stacks, whereas the RX-94 is designed to test two 8-inch test sieve stacks simultaneously.

Now, when you are building out or upgrading your lab setting, it is important that you explore all your options. This means not only investigating all sieve shaker options but other devices like air jet sieves and dynamic image analysis systems as well.

W.S. Tyler has been a leading entity in the particle analysis industry for over 140 years and wants to help you pinpoint the various particle analysis devices that work for you.

To continue down the road towards accurate and repeatable particle analysis results, read the following articles to learn more about the particle analysis device available to you:

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.