Flow Control
DN25
Brooks MT3809 / MT3819 Metal-Tube Variable-Area Flowmeter Connection Size
About this part
DN25 identifies a 25 mm nominal, 1-inch process connection used on Brooks MT3809 and MT3819 metal-tube variable-area flowmeters. It is not a complete Brooks model or ordering code. Flow range, meter-body size, float, flange class, wetted materials, calibration, indicator, electronics and approvals depend on the complete configured-unit model and nameplate
Configurations vary. Verify the exact unit before choosing a replacement.
Key Facts
Specifications
| Identifier type | Nominal process-connection size; not a complete Brooks model code |
| Nominal size | DN25 (25 mm nominal) |
| Inch designation | 1 inch |
| Documented models | MT3809 and ETFE-lined MT3819 metal-tube variable-area flowmeters |
| Measuring principle | Variable area (rotameter) |
| Flow indication | Magnetic coupling between the float magnet and mechanical dial pointer |
| MT3809 media | Gas, liquid and steam applications |
| MT3819 media | Liquid and gas applications requiring an ETFE-lined primary meter |
| Flow accuracy | Standard ±2% full scale; optional ±1% full scale |
| Repeatability | 0.25% full scale |
| Family installation orientation | Vertical within 5% of true vertical, with bottom inlet and top outlet |
| Magnetic-interference boundary | Do not locate near magnetically interfering components |
What Does DN25 Mean?
DN25 states the nominal process-connection size, not the complete flowmeter configuration.
| Segment | Field | Interpretation |
|---|---|---|
| DN | Sizing system | Metric nominal-diameter designation used for the process connection. |
| 25 | Nominal size | 25 mm nominal connection class; Brooks documentation pairs this size with a 1-inch connection. |
| Complete model code | Configured unit | Required to establish the model, meter body, float and range, connection standard and pressure class, materials, calibration, indication, electronics and approvals. |
Documented DN25 Standard-Body Capacity Options
These capacities apply to legacy standard meter-size 10 configurations documented in the September 2008 family manual. They are option-table values, not specifications for every DN25 unit.
| Legacy model | Float | Water full-scale capacity | Air full-scale capacity |
|---|---|---|---|
| MT3809, meter size 10, DN25 / 1 inch | A | 1,200 l/h (5.2 gpm) | 19 scfm (30 Nm³/h) |
| MT3809, meter size 10, DN25 / 1 inch | B | 1,500 l/h (6.6 gpm) | 31 scfm (49 Nm³/h) |
| MT3809, meter size 10, DN25 / 1 inch | C | 2,400 l/h (10 gpm) | 41 scfm (65 Nm³/h) |
| MT3809, meter size 10, DN25 / 1 inch | D | 3,500 l/h (15 gpm) | 65 scfm (100 Nm³/h) |
| MT3819, meter size 10, DN25 / 1 inch | A | 1,400 l/h (6.2 gpm) | 26 scfm (41 Nm³/h) |
| MT3819, meter size 10, DN25 / 1 inch | B | 2,000 l/h (8.8 gpm) | 37 scfm (58 Nm³/h) |
| MT3819, meter size 10, DN25 / 1 inch | C | 2,400 l/h (10 gpm) | 44 scfm (70 Nm³/h) |
| MT3819, meter size 10, DN25 / 1 inch | D | 3,000 l/h (13 gpm) | 55 scfm (87 Nm³/h) |
Replacement and Configuration Boundary
DN25 alone is insufficient for selecting or replacing a configured flowmeter.
Documentation Downloads
Local PDF copiesPart Photos
5 imagesHistorical archive images for identification, labels, connectors, and condition reference, not current inventory.
Historical Listings & Prices
Historical listing data, not a current offerThe typical recorded price range is $122.85 to $305.77. Based on 2 archived listing records; not a current offer, appraisal, or confirmed sale price.
View archived listing titles
- Brooks Metal Tube Variable Area Flowmeter MT 3819 DN25