Getting the Recipe Right: Why Engineering Determines Long-Term System Performance

It's not uncommon for customers to be surprised by the amount of information required before a system can be designed.

We ask about far more than the type of dust or debris being collected. We know from experience, our competitors do not. But that’s what sets us apart.

We want to understand the material itself (its physical characteristics), facility layout, building height, utilities, available power, environmental conditions, number of operators, housekeeping practices, future expansion plans, and the daily habits of the people who will use the system.

“Experience has taught us that if using the equipment requires employees to walk too far, interrupt their workflow, or take extra time, it often won't be used as intended. Good engineering considers both the process and the people performing it.” - Stephen Doria, Director of Operations, Air Dynamics

To someone purchasing a central vacuum or dust collection system, those questions can seem excessive.

To an engineer, they're the ingredients that determine whether a system will perform reliably for years—or gradually lose efficiency because it was never designed for the conditions in which it actually operates.

Think about baking a cake.

A recipe calls for specific ingredients in specific amounts, mixed in a specific order. Leave out an ingredient, substitute another, or change the measurements, and the finished product changes.

Industrial vacuum and dust collection systems work the same way.

Every system is engineered around a specific set of assumptions. We calculate airflow requirements, pressure losses, conveying velocity, material characteristics, pipe routing, operator demand, and environmental conditions before selecting equipment and designing the piping network.

Change one of those ingredients, and you've changed the recipe.

Sometimes the change is obvious.

Sometimes it isn't discovered until the system begins losing performance.

One customer had a central vacuum system designed specifically to collect dry sawdust during housekeeping.

The system performed exactly as intended—until the building roof developed leaks.

Rainwater mixed with the sawdust before employees vacuumed it into the system. From the operator's perspective, it was still sawdust. From an engineering perspective, it had become an entirely different material.

Instead of flowing through the piping, the wet sawdust adhered to the pipe walls. Every shutdown allowed another layer to dry and harden until the buildup became almost concrete-like. Over time, the inside diameter of the piping decreased, reducing airflow velocity and making it even easier for additional material to settle.

Eventually, the restrictions became severe enough to reduce productivity and require extensive maintenance.

The moisture also introduced additional concerns. Damp organic material can support mold, fungi, and bacterial growth. Under the right conditions, microbial activity may generate heat that increases the potential for spontaneous combustion, while sulfur compounds may create unpleasant odors.

The solution required removing the hardened material, repairing the roof leak, and retraining employees not to vacuum liquids into a system engineered exclusively for dry material.

The equipment hadn't failed.

The operating conditions had changed.

Another customer generated galvanized dust which the conveyance system was designed to handle. However, the facility's process included moisure present at the bottom of the hopper which was not disclosed in the original spec. The fine particles reacted rapidly with moisture which quickly hardened like concete, compromising the effectiveness of the system. The environmental conditions changed which resulted a miappropriation of design. 

As the material hardened inside the hopper discharge and pneumatic conveying line, restrictions developed that reduced airflow through the dust collector. Eventually, the vacuum could no longer maintain sufficient airflow through the filters. Dust and moisture quickly blinded the filters, requiring replacement and increasing maintenance costs.  

The long-term solution was to eliminate the pneumatic conveying system altogether and switch to manually emptying collection drums beneath the hopper. While the clogging issue was resolved, the customer traded an automated process for ongoing manual labor.

The equipment wasn't defective. The design wasn't wrong.

The process conditions did not match the specifications given to engineering and the result was an ineffective process. This is why it is imperative to provide as much "environmental" conditions in the process as possible at the start of a project. 

Perhaps the most common issue we encounter has nothing to do with equipment failure.

It has to do with operation.

One food manufacturer experienced recurring piping blockages even though the central vacuum system had been properly engineered for the application. The facility included several long vertical drops from the ceiling before transitioning through elbows and horizontal piping back to the vacuum producer.

Operators naturally wanted to clean large quantities of material as quickly as possible. Unfortunately, central vacuum systems are not designed to function like pneumatic conveying systems. The lack of inlet air at the hose due to placing the hose in a pile of fines was the main cause of the issue.

A central vacuum is a high-pressure, low-volume system. Its performance depends on maintaining enough air velocity to keep material suspended while it travels through the piping network. In other words, always remember to let your vacuum hose breathe more than you let it eat.

When too much material enters the hose at one time, airflow can no longer support it.

Instead of the material being able to make the vertical rise of the piping, and traveling through the elbows, the material falls back into the drop, compacts, and gradually creates a blockage.

The system wasn't undersized.

It was simply being operated beyond the conditions it was designed to handle.

That distinction is important. That's why we train operators not only on the functionality of the equipment and how to use it, but also on the "why" behind the engineering. In this case, the operatpr forgot their training.

Every industrial vacuum system has operating limits.

The difference is how well those limits are understood during design.

At Air Dynamics, engineering extends well beyond selecting a vacuum producer. We evaluate the entire conveying network to reduce the likelihood of clogging and maintain performance throughout the life of the system.

One of the most important engineering considerations is maintaining conveying velocity—the speed at which air moves through the piping to keep material suspended.

Stephen Doria, Director of Operations at Air Dynamics, often explains it with a simple analogy:

" Imagine drinking through two straws—one narrow and one much wider. If you use the same amount of suction on both, the air travels much faster through the narrow straw because it's being forced through a smaller opening. In the wider straw, that same suction is spread over a larger area, so the air moves more slowly. Industrial vacuum conveying systems work the same way. It's not just about how much air the system moves—it's about maintaining enough air velocity to keep material suspended and moving through the piping. If the velocity drops too low, the material can settle, clog the line, or reduce system performance.”

That's why Air Dynamics carefully designs pipe diameters throughout the system rather than using the same size pipe everywhere. As additional operators and branches are added, the piping is gradually increased in size using tapered mains to maintain conveying velocity while accommodating greater airflow. It's one of many engineering decisions that helps reduce clogging and improve long-term system performance.

That includes:

• Performing pressure-loss calculations on the longest and most demanding piping runs before equipment is selected.
• Designing tapered mains that maintain conveying velocity as additional operators join the system.
• Providing adequate straight pipe after direction changes so airflow and conveyed material can regain velocity before encountering another elbow.
• Minimizing unnecessary turns that increase turbulence and create opportunities for material to settle.
• Designing maintainable piping with accessible cleanout locations rather than creating systems that require cutting apart piping when blockages occur.
• Selecting positive displacement vacuum producers, when appropriate, that automatically increase pulling force as system resistance increases, helping recover from temporary blockages before they become major maintenance events.

These engineering decisions are largely invisible after installation, but they have a tremendous impact on long-term system reliability.

One of our engineers learned this firsthand during a customer demonstration.

While demonstrating a bulk pickup wand, an operator immediately buried the wand into a large pile of cornmeal. Within seconds, the piping clogged. Rather than allowing the system to meter the material at the rate it was designed to convey, the operator overwhelmed the available airflow.

Fortunately, the positive displacement vacuum producer gradually increased suction until the blockage eventually cleared without dismantling the piping.

It became a valuable training exercise.

The equipment hadn't failed.

The operator had unknowingly exceeded the system's conveying capacity.

That experience reinforces an important lesson we share with every customer: even the best-engineered system depends on proper operation. Training is essential to success.

Manufacturers sometimes view a central vacuum or dust collection system as another piece of equipment.

We view it as an engineered process.

The questions asked during design establish the recipe. The engineering ensures that recipe works.

Installation puts it into operation. Operator training and proper maintenance keep it performing as intended.

When one of those ingredients changes—whether it's the material being collected, environmental conditions, facility modifications, or operating practices—the results change as well.

That's why Air Dynamics spends so much time asking questions before the first drawing is ever produced.

It's about understanding the customer's process well enough to design a system that continues performing long after installation.

Anyone can sell equipment. We invest in engineering.