Understanding the Role of Bell Mouths in Source Capture Systems. 

 

When it comes to industrial air filtration systems, choosing the lowest-cost option upfront does not always lead to the lowest operating cost in the long run. Proper ductwork design and source capture setup play a major role in system performance, energy efficiency, and overall air quality. 

With today’s manufacturing workforce challenges, companies are placing more focus on creating cleaner, healthier work environments to help retain and attract employees. Improving indoor air quality is an important part of creating a safer and more comfortable workplace. 

Small improvements to your filtration system can often provide significant benefits, especially when it comes to system performance, contaminant capture, and operating costs. 

One common area where performance can be improved is the design of the hood at the source of contamination. 

The Problem with Raw Edge duct 

One of the simplest and least expensive hood designs is the raw-edge flex duct. This design is essentially an open duct that extends close to the source of smoke, mist, or airborne contaminants. 

While raw-edge ducts are easy and inexpensive to install, they provide some of the poorest performance when it comes to capturing contaminants at the point of generation. Because the opening has no tapered entry or airflow control, the hood pulls air from multiple directions, including areas behind the hood where clean air is being unnecessarily drawn in. 

This creates turbulence and airflow losses that reduce capture efficiency. Depending on airflow conditions, an 8-inch duct with a raw edge opening can perform more like a smaller duct because air becomes compressed and disrupted as it enters the duct. These inefficiencies can increase energy usage, reduce contaminant capture, and potentially require a larger fan to achieve the needed airflow. 

From a total cost of operation standpoint, a raw-edge hood is often not the most effective solution. 

The Benefits of a Bell Mouth Hood 

There are many hood options available, but one simple and cost-effective improvement is the bell-mouth hood. 

A bell mouth gets its name from its smooth, tapered shape that resembles the opening of a bell. This design allows air to enter the duct more smoothly, reducing turbulence and minimizing pressure loss. 

The flanged design helps prevent air from being pulled in from behind the duct opening, while the smooth entry profile improves airflow direction and efficiency. This allows the system to capture smoke, mist, and other contaminants more effectively while requiring less energy to move air through the system. 

By improving airflow performance, a bell mouth can help increase capture efficiency, improve equipment operation, and reduce unnecessary operating costs. 

Improving Your Source Capture System 

If your facility has visible smoke, mist, or haze, take a look at your current source capture setup. 

Ask yourself: 

• Are there areas where smoke or mist is escaping before being captured? 

• Are there open ducts that simply stop near a machine or work area? 

• Could a bell mouth hood improve airflow and capture performance? 

• Are there areas of the process that could be enclosed for better control? 

Sometimes, small changes to your source capture system can make a significant difference in air quality, equipment performance, and employee comfort. 

Source Capture Solutions for Industrial Air Quality 

Proper hood design and ductwork layout are important parts of getting the best performance from an industrial air filtration system. At Bee Clean Specialties, we work with a wide range of air cleaning equipment and source capture systems from leading manufacturers, including SmogHog®, Tri-Mist®, MistBuster®, Trion®, Aerocology®, and many other industry brands. 

Whether your system is capturing oil mist, smoke, welding fumes, or other airborne contaminants, the right combination of hood design, ductwork, and filtration equipment can make a major difference in overall system performance. 

Our team can help evaluate your current setup and identify opportunities to improve capture efficiency, reduce energy costs, and create a cleaner work environment. 

Thanks for Reading, 

The Bee Clean Team 

847-451-0844 
contact@beecleanspecialties.com