- Official UK and Ireland channel partner
- UK technical support available
- Model selection and configuration support
Dwyer SFI-100/300/300F/400/700 Sight Flow Indicators
Select a window or tube-style indicator for local visual confirmation of flow in compatible gas and liquid pipelines.
Key highlights
- Viewing: Single window, double window or tube
- Indication: Impeller, flapper or unobstructed view
- Connections: Threaded or raised-face flanged
- Bodies: Bronze, brass, carbon steel, cast iron or 316 stainless steel
- Service: Compatible gases and liquids
Dwyer SFI-100/300/300F/400/700 sight flow indicators provide local observation of flow or pipeline contents across five related construction styles. The combined family supports selection by viewing arrangement, moving indicator, body material, connection and operating limit.
All five series provide visual indication only. They are not calibrated flow meters, switches, controllers or electrical transmitters. An impeller or flapper makes movement easier to identify, while unobstructed window and tube versions allow direct observation of compatible process media.
SFI-100 uses a single window and rotating impeller. The threaded SFI-300 family adds double-window versions with an impeller, no moving indicator or a flapper. SFI-300F extends the double-window concept to larger raised-face flanged connections, with clear-view SFI-350F and flapper-operated SFI-360F configurations.
SFI-400 provides tube-style viewing without a moving indicator and is available in threaded or flanged constructions. SFI-700 combines a full-view tempered borosilicate tube with a visible red impeller and internal wipers that clean the tube when it is rotated.
Operating limits vary materially by construction. Selection must match the process medium to every wetted material and account for line size, connection standard, pressure, temperature, flow velocity, mounting orientation and access for inspection or service. Published applications include hydraulic tanks and lines, pressure vessels, coolant tanks and oil reservoirs.
Key Features
- Five-series selector: Compare compact window, larger flanged and full-view tube constructions on one family page
- Passive local indication: Confirm flow or pipeline contents without electrical power, signal wiring or control hardware
- Indication choices: Select a rotating impeller, flapper or clear viewing path to suit the observation requirement
- Connection coverage: Choose threaded or raised-face flanged arrangements across series-specific sizes from 1/4 to 6 inches
- Wetted-material choices: Match body, window or tube, gasket and indicator materials to the compatible process medium
- Serviceable windows: SFI-100, SFI-300 and SFI-300F use removable windows for inspection and replacement of wearing parts
- Full-view tube styles: Observe the process from multiple angles with SFI-400 or the impeller-equipped SFI-700
- Series-specific limits: Match the selected construction to its pressure, temperature, velocity and mounting limits
Specifications
| Series Selection | |
| SFI-100 | Single-window indicator with rotating impeller and threaded connections |
| SFI-300 | Threaded double-window family: SFI-300 with impeller, SFI-350 without a moving indicator or SFI-360 with flapper |
| SFI-300F | Raised-face flanged double-window family: SFI-350F without a moving indicator or SFI-360F with flapper |
| SFI-400 | Tube-style indicator without a moving element; threaded or raised-face flanged construction |
| SFI-700 | Tube-style indicator with visible red impeller and internal tube-cleaning wipers; threaded construction |
| Function and Service | |
| Function | Local visual indication of flow or pipeline contents; no calibrated flow-rate measurement, switching, control or electrical output |
| Media | Compatible gases and liquids; confirm compatibility with every wetted material for the selected model |
| Impeller-model velocity limit | 5 ft/s maximum with liquids; 5,000 ft/min maximum with gases |
| Wetted Materials and Indication | |
| SFI-100 | Tempered-glass window; bronze body; Buna-N, fluoroelastomer or PTFE gasket; ABS or selected 316 stainless steel impeller |
| SFI-300 family | Tempered-glass windows; bronze or selected 316 stainless steel body; Buna-N, fluoroelastomer or PTFE gasket; impeller, no moving indicator or 304/316 stainless steel flapper by configuration |
| SFI-300F family | Tempered-glass windows; carbon steel or 316 stainless steel body; Buna-N, fluoroelastomer or PTFE gasket; no moving indicator or 316 stainless steel flapper |
| SFI-400 | Borosilicate tube; cast iron or 316 stainless steel body; PTFE gasket; no moving indicator |
| SFI-700 | Tempered borosilicate tube; brass or 316 stainless steel body; fluoroelastomer gasket; red Acetal impeller |
| Connections and Sizes | |
| SFI-100 and SFI-300 | 1/4 to 2 inch threaded connections; female NPT standard, with BSPT or BSPP options |
| SFI-300F | 1-1/2, 2, 3, 4 or 6 inch raised-face flange connections |
| SFI-400 | 1/2 to 4 inch; 400CI cast iron and 400SS stainless steel versions use female NPT, while 400F uses a 1 to 4 inch raised-face flange |
| SFI-400 construction limits | 400CI is listed only from 1 to 2 inches; 400F is listed from 1 inch upwards |
| SFI-700 | 1/4 to 1-1/2 inch threaded connections; female NPT standard, with BSPT or BSPP options |
| Pressure and Temperature | |
| SFI-100 and SFI-300 | 125 psig (8.62 bar) and 93°C (200°F) standard; MP versions are rated to 150 psig (10.34 bar) |
| SFI-100/300 option limits | 48°C (120°F) maximum with the W2 window option; 77°C (170°F) maximum with the I1 impeller option |
| SFI-300F | 150 psig (10.34 bar); 93°C (200°F) |
| SFI-400 | 50 psig (3.45 bar); 93°C (200°F) |
| SFI-700 | 230 psig (15.86 bar); 100°C (212°F) |
| Options and Installation | |
| Window and gasket options | W2 Plexiglass window, G1 PTFE gasket or G2 fluoroelastomer gasket on compatible SFI-100/300 configurations; G1 or G2 gasket on SFI-300F |
| SFI-100/300 indicator options | Selected configurations support 316 stainless steel or Monel shafts, alternative ABS or 316 stainless steel impellers, no impeller on SFI-100, or a 316 stainless steel flapper on SFI-360 |
| MP pressure option | 150 psig maximum-pressure version with fluoroelastomer gaskets for compatible SFI-100/300 models |
| Window-style mounting | SFI-100/300 and SFI-300F may be mounted horizontally or vertically; SFI-360 and SFI-360F flapper versions are horizontal only |
| SFI-400 installation | Best suited to vertical pipelines where the indicator is not subjected to mechanical strain |
| Service access | SFI-100, SFI-300 and SFI-300F use removable windows; SFI-700 uses internal wipers operated by rotating the glass tube without stopping flow |
Support
Able Instruments are an official UK and Ireland channel partner for DwyerOmega, providing application advice, configuration support and quotation assistance for the SFI-100, SFI-300, SFI-300F, SFI-400 and SFI-700 family.
- Model selection: Support matching the viewing method, connection type, line size and access requirements
- Option compatibility: Checks for body, window or tube, gasket, indicator and thread options against the process medium and operating limits
- Installation support: Advice on mounting orientation, piping strain, pressure and temperature limits and service access
- Documentation support: Help with the family datasheet, model code, material compatibility and replacement requirements