Rotork Fairchild Model 18 Vacuum Relief Regulator is designed for systems that require system vacuum control up to full vacuum. The Model 18 Vacuum Relief Valve uses a force balance principle to open the relief valve and allow atmospheric air to lower vacuum levels when the set point is exceeded.
Operating Principles
The model 18 Vacuum Relief Valve uses a force balance principle to open the Relief Valve and allow atmospheric air to lower vacuum levels when the set point is exceeded.
Vacuum is transmitted to the top of the M18 Diaphragm Assembly, exerting an upward force on the diaphragm. When you adjust the range screw for a specific set point, the Positive Bias Spring compresses and exerts a downward force on the top of the Diaphragm Assembly. As long as the vacuum force acting on the Diaphragm Assembly produces a force less than the spring force acting on the top of the Diaphragm Assembly, the Relief Valve remains closed. When vacuum increases beyond the set point, the assembly moves upward, lifting the Relief Valve from its seat and allowing atmospheric air in, lowering vacuum level in the system.
If vacuum pressure decreases below the set point, the assembly moves downward closing the Relief Valve.
Features
Model 18 Vacuum Relief Regulator Features
- Full vacuum capability - accurate control in vacuum applications
- Control sensitivity of less than 1/8" water column allows use in precision applications ? Stability of regulated vacuum or pressure is maintained under varying flow conditions through the use of an aspirator tube which adjusts the inner valve in accordance with the flow velocity
- A balanced supply valve to deliver consistent and reliable accuracy
- 30 in Hg, 762 Torr, 102 kPa maximum supply vacuum ? Three relief vacuum ranges from 4 in Hg, 140 mBar, 14 kPa, up to 30 in Hg, 1000 mBar, 100 kPa
- Up to 8 SCFM, 68 m3/hr flow capacity
- Separate control chamber eliminates hunting and buzzing
- Unit construction permits you service the Model 18 without removing it from the line
Specifications
Model 18 Vacuum Relief Regulator Specifications
| Specification | Description |
|---|---|
| Maximum Vacuum Capacity | 30 in Hg (762 Torr) (102 kPa), up to “Full” Vacuum |
| Flow Capacity | 8 SCFM (68 m3/hr) @29" Hg VAC |
| Sensitivity | Less than 1/8" (.32 cm) Water Column |
| Ambient Temperature | -40°F to +200°F (-40°C to +93°C) |
| Material of Construction |
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Q & A
Model 18 Vacuum Relief Regulator Q & A:
Downloads
Download Rotork Fairchild Model 18 Vacuum Relief Regulator Datasheet
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