The Science Behind the Combination3® Truck

WHAT MAKES IT DIFFERENT?

USST's Combination3® Truck
USST’s Combination Truck

In a word, Gravity!

The CombinationTruck is a unique, ambidextrous tool. It can vacuum using suction and pump using positive pressure, as well as perform jetting. Here, we’re going to examine the differences between traditional technology versus the powerful capabilities of the CombinationTruck.

Let’s take a look at how traditional vacuum technology works

Vacuum technology has been around for 50-years and is typically the first tool called upon for cleaning most pipes and tanks. A vacuum uses the flow of air to move debris into the debris box.  In a dry environment, this approach works well. Vacuum technology begins to be less effective with the presence of water. As the amount of water increases, the effectiveness of removing debris such as sand and grit becomes less effective. This is because water is lighter than the debris to be removed. As a result of this natural consequence of gravity, the debris box fills with water. Essentially, the vacuum moves the lighter material first. This is especially true for large diameter pipes. As pipe diameter increases, the flow of water also increases exponentially.

How does the CombinationTruck work differently?

The Combination Truck can overcome vacuum limitations by switching to the pumping mode coupled with a pressurized debris box. This process, known as the GritGone Process®, provides the ability to minimize or even eliminate the amount of water hauled off-site. If a tank or pipe can be cleaned while in service, the amount of water to be hauled off is minimized.

Ironically, the more water found in a structure while cleaning means less water to be hauled offsite.  “Wait! What?”, you may ask yourself. Let us explain further. If the pipe or tank is full, the Combination Truck uses water instead of air to move the debris.  In other words, vacuum uses air to move whatever is in its path and both water and debris travel into the debris box and remain when the air leaves. Conversely, when water is used to transport debris to the debris box, only the debris remains in the box since the water leaves.

Let’s not forget about the limitations of tank depth and height

In addition to the struggle with excessive amounts of water being sucked into a debris tank, another limitation imposed by gravity is pipe depth or tank height. A typical vacuum can suck, or pull up, and is effective up to one atmosphere of pressure, roughly 30-feet. When using the pumping capabilities of the CombinationTruck, the pump can ‘push’ the water and debris significantly more than 30-feet. When considering the height of a typical vacuum truck, this essentially means the limit of effective vacuum is about 20-feet below ground. Once depth becomes an issue, the force of gravity simply cannot be overcome by vacuum suction.

USST’s Combination Truck reaching over tank walls to perform cleaning while in operation.

Benefits of cleaning in a wet environment

An added benefit of cleaning while in service, or wet/submerged cleaning, is the elimination of potentially hazardous confined space entry, creating a safer work environment for crew members. If conditions allow, the CombinationTruck can clean both tanks and pipes while in service, reducing or even eliminating the need for confined space entry and avoiding potentially costly bypass.

A combination of services that can be performed in full operation

Uniting the unique cleaning capabilities of the CombinationTruck with the ability to see inside tanks and pipes is a powerful combination of services. When visibility is crucial to the job ahead, USST’s CCTV/sonar assessment and verification services allow us to see and verify the conditions of both tanks and pipes in real time while in full operation with no bypass or facility shut down. The CombinationTruck performs the cleaning portion of the job, as described above. Together, these tools allow USST to offer a unique approach to solving problems.

Learn more about USST’s new See, Clean & Verify services here.

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