DN270-DN128 / Fine-bubble and coarse-bubble aeration
DN270 and DN128 Disc Diffusers
One PEROTAC catalogue covers two different disc diffusers. DN270 uses an EPDM membrane for fine-bubble aeration, while DN128 is a coarse-bubble disc for aeration and mixing. Their airflow and head-loss characteristics differ, so the two designs should be compared by treatment duty.
Range technical data
- DN270 design airflow
- 2–6 m³/h per diffuser
- DN270 basin depth
- 1.5–7 m
- DN128 airflow
- 6–24 m³/h
- Connection thread
- 3/4 in NPT; DN128 specified as male
DN270 fine-bubble and DN128 coarse-bubble data are separate. Match airflow and head loss to the selected diffuser; the DN270 temperature limit must not be applied to DN128.
Series catalogue ↗Series overview
Overview
DN270 is the fine-bubble device in this catalogue, with an EPDM membrane, retaining ring and disc construction. Its application list includes activated-sludge and treatment-process aeration. DN128 is the coarse-bubble device, with an EPDM rubber cap and ABS main body; the source lists water purification, wastewater treatment, equalization and mixing.
Both devices distribute blower air into water, but their bubble type and operating data are separate. Selection should consider process objective, available air supply, installation connection and the published head-loss curves. DN270 and DN128 are covered in the same catalogue, with separate construction and operating data for each diffuser.
Features
- DN270 fine-bubble EPDM membrane
- DN128 coarse-bubble EPDM cap and ABS body
- Separate airflow and head-loss data
- Distinct aeration and mixing duties
Applications
- Activated-sludge aeration
- Wastewater-treatment aeration
- Equalization-basin mixing
Materials
DN270: EPDM membrane with polypropylene retaining ring and disc. DN128: EPDM rubber cap and ABS main body.
Operating conditions
Use the airflow and head-loss data for the selected diffuser. DN270 lists a design airflow of 2–6 m³/h per diffuser, basin depth 1.5–7 m and maximum temperature 100 °C. DN128 lists airflow 6–24 m³/h. Do not transfer the DN270 temperature limit to DN128.
Before selecting
- Choose fine-bubble DN270 or coarse-bubble DN128 according to the aeration and mixing duty.
- Match airflow per diffuser, water depth and head loss to the selected model and air-supply system.
- Confirm membrane/body compatibility, connection and required backflow-prevention configuration.
Series questions
What is the practical difference between the two diffuser models?
DN270 is the fine-bubble EPDM membrane disc; DN128 is the coarse-bubble diffuser with an EPDM cap and ABS body. Their airflow and head-loss data differ.
Is the same airflow suitable for both models?
No. DN270 lists a design range of 2–6 m³/h per diffuser, while DN128 lists 6–24 m³/h. Select the diffuser and air supply together using the applicable data.
Technical documents
DN270-DN128 PDF
2 pages · 282,2 KB
Choose the diffuser by aeration or mixing duty, airflow per diffuser, water depth, head loss and connection.