Model 24 Snap Acting Relay is a highly accurate differential relay with snap-acting switching. The output of the unit will go to supply pressure when the signal is equal to or greater than the setpoint. The signal pressure must fall below the set point to return the output to zero. This pneumatic relay's near zero throttling and pilot staging, result in true snap-action in your application.
Operating Principles
The Model 24 Snap Acting Relay is a highly accurate differential relay with snap-acting switching. The output of the unit will go to supply pressure when the signal is equal to or greater than the setpoint. The signal pressure must fall below the set point to return the output to zero.
Features
Model 24 Snap Acting Relay Features
- Control sensitivity of 1/8" water column - designed for use in precision applications
- Balanced supply valve minimizes the effects of supply pressure variation
- Aspirator tube design compensates for output pressure droop under flow conditions
- Separate control chamber isolates the diaphragm from the main flow to eliminate hunting and buzzing
- Unit construction allows servicing without removal from air line
Specifications
Model 24 Snap Acting Relay Specifications
| Category | Specification |
|---|---|
| Maximum Supply Pressure | 120 psig (8.0 bar / 800 kPa) |
| Minimum Supply Pressure | 10 psig (0.7 bar / 70 kPa) — use separate supply option if inlet pressure is below 10 psig |
| Flow Capacity | 14 SCFM (23.8 m3/hr) @ 100 psig supply |
| Exhaust Capacity | 14 SCFM (23.8 m3/hr) @ 100 psig drop |
| Signal Range | 2” W.C. to 120 psig (0.006–8.0 bar / 0.63–800 kPa) |
| Change in Signal to Operate | Depends on range: ? 2” W.C.–10 psig: 0.2” W.C. ? 0.5–30 psig: 0.1 psig ? 1–60 psig: 0.2 psig ? 2–120 psig: 0.5 psig |
| Repeatability | 0.2” water column (0.5 cm) |
| CV Rating | 0.23 |
| Mounting Options | Pipe or panel mounting |
| Air Consumption | < 0.015 SCFM (0.03 m3/hr) @ 100 psig inlet |
| Ambient Temperature Range | –40 to +200 °F (–40 to 93.3 °C) |
| Body & Housing Materials | Aluminum casting |
| Trim Materials | Stainless steel, zinc-plated steel |
| Diaphragm Materials | Buna-N and Dacron |
| Valve Options | Normally Open (NO) or Normally Closed (NC) |
| Pressure Range Options (Codes) | ? 2" W.C.–10 psig ? 0.5–30 psig ? 1–60 psig ? 2–120 psig |
| Pipe Size Options | 1/4" NPT, 3/8" NPT, 1/2" NPT |
| Optional Features | Tapped exhaust (E), fluorocarbon elastomers (J), knob adjustment (K), tamper-proof (T), BSPT threads (U), separate supply (SS) (E and SS not compatible) |
Q & A
Model 24 Snap Acting Relay Q & A
Downloads
Download Rotork Fairchild Model 24 Snap Acting Relay Datasheet
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