Pros and Cons

Internally vs externally fed screens each handle flow, solids, and cleaning differently. This quick comparison breaks down the pros and cons so you can choose the right screen design for your application.

When comparing internally vs externally fed screens, cleaning method and solids type usually drive the decision.

Internally Fed Screens

Pros

• Handle higher flow rates without the same turbulence issues seen on some external-feed designs.
• Process oily waste streams better, since the feed stays inside the drum and limits splash and aerosol.
• Accommodate fibrous or stringy solids (depending on drum design and spray/brush setup).

Cons

• Don’t self-clean as easily, so operators often add sprays, brushes, or more frequent manual cleaning.
• Require internal washing/maintenance access, which can increase service time.
• Need tighter housekeeping because buildup can reduce open area and performance over time.

In short: Choose internal feed when you need flow capacity and better oil handling, and you can support cleaning/maintenance.

Externally Fed Screens

Pros

• Self-clean more effectively, because the spray typically hits the outside surface where solids collect.
• Simplify maintenance, since crews can often access cleaning components more easily.
• Work well for many municipal/industrial applications, especially with consistent influent.

Cons

• Struggle more with oils/grease, because splashing and carryover can increase fouling.
• Depend more on proper spray performance, so clogged nozzles can reduce screening fast.
• Need careful flow control, since uneven distribution can lower efficiency.

On the other hand: Go external feed when you want easier self-cleaning and simpler service, and your stream isn’t heavy in oils/grease.

If you’re still deciding between internally vs externally fed screens, Dontech can recommend a configuration based on your flow, solids, and maintenance goals.