Flow aids can resolve bridging, arching, and other material blocks, but many give limited results and come with hidden costs. So instead of solving the problem, they can even create new ones—and hinder productivity and revenue.
Hammers and Manual Cleaning
Hammers are the cheapest flow aid you can possibly find… or so you think. While you can get a hammer for less than $20, you’re actually paying for manpower hours and the downtime while workers clear out the clogged material from the vessel.
That can be very expensive. One of the biggest cement companies in Southeast Asia calculated that they lost $12,000 per hour of downtime. In North America, this downtime is more like $25,000 an hour.
Hammering can also damage machines, and it creates the risk of worker injury. It’s also very inefficient: material can still cling to vessel walls compromising product consistency and even leading to spoilage.
Fluidizers are sometimes the default flow aid because they have already been pre-fitted into the vessel. The rubber disks are connected to air piping and use a combination of gentle vibration and aeration to activate the material.
While the fluidizers work for very light powders like flour, they can’t activate heavy, damp, or sticky materials. They have a small effective radius, so you may need to install several units. Since the disks run continuously, energy consumption is also high.
Fluidizers that are installed inside the vessel can also degrade, and material can be trapped inside the disks. This is a risk for sanitary processes and it creates cleaning and maintenance challenges.
Vibrators, as the name implies, vibrate the material to shake it free from the vessel wall and collapse any bridging and blocks.
However, many materials can actually become more compact when it is shaken. In fact, vibrators are sometimes used to compress materials before they are stored or transported. That’s effective in a warehouse, but not in a silo or hopper where you want materials to move.
Even for materials to respond to vibration, this flow aid can still be problematic. It can cause metal fatigue and eventually lead to vessel damage. It uses a lot of air and energy to operate. It does not completely flush material that clings to walls or pipes, so you will still need to do periodic shutdowns for cleaning.
This flow aid blasts air through material blocks. While powerful, it is not always effective. Air can channel through the holes and diminish its effect. It requires a large amount of plant air and energy to operate, and will still leave a lot of material on the vessel that needs to be manually cleaned.
The large units are also difficult to install in small vessels, and the metal recoil contributes to vessel wear and tear. Flying material can also enter the nozzle and solenoid valve, so the system is prone to damage and maintenance issues.
How to Find the Most Efficient Flow Aid
When selecting a flow aid, don’t just look at the initial cost of installation. Look at the hidden costs—downtime and manual labor, consumption of energy and plant air, cleaning and maintenance, and even the financial and legal impact of a worker injury.
To avoid these costs, select a flow aid based on these factors:
- Speed and efficiency. How fast will your material flow? Will it shorten your production time? Can the flow aid remove all stagnant material, or will you still need to hammer or manually clean your vessels?
- Operating costs. How much energy does it consume during operation? Does it use energy efficiently, i.e. will the units run continuously or in short, specific durations? What is the cost of cleaning and maintaining the flow aid itself, and how does it impact the maintenance of the vessel in which it is installed?
- Hygiene and safety. Consider risks to your product quality (like material contamination and spoilage) and risks to your people (worker injuries during manual cleaning, etc.).
Companies Choose AirSweep as the Most Cost-Effective Flow Aid
Many plants that used fluidizers, vibrators, and other flow aids eventually switched to AirSweep because they got better results. It improved productivity, product quality, and had lower energy and maintenance costs.
You can read about 7 companies that switched from vibrators to AirSweep or see how AirSweep’s features compare to the other flow aids in the market.
If you have any other questions about AirSweep or need more information about how it can work on your process, contact us for a personal consultation or customized proposal.