Automatic Drain Valves are an important safety feature for compressed air applications with downstream pneumatic equipment.
A conventional shut off valve can trap compressed air in pneumatic equipment, which could create a potentially dangerous situation. Lance Safety Exhaust Automatic Drain Valves allow the down stream pressure to be released when the valve is in the closed, “off” position.
Valve Design Features
- Blowout proof stem
- Adjustable packing gland
- Glass reinforced Teflon seats
- NPT end connections
- 2 Piece construction
- Standard Stainless Steel Ball & Stem
- Drilled vent port
- Drilled vent hole in ball
Recommended Ratings: Size & Max PSI
- 1/4″, 3/8″, 1/2″: 200 Max PSI
- 3/4″, 1″: 200 Max PSI
- 1-1/4″, 1-1/2″, 2″, 2-1/2″, 3″, 4″: 120 Max PSI
Common Valve Options Available
- Handles: Locking, Oval, Tee, Extensions, Lockable Extensions
- Handle Extensions: 1-1/4″, 2-1/4″, 3-1/4″. We also offer a full range of over 40 options, please contact us for more details.
- Lockable Extensions: 2-1/4
*Mounting pad not available on SS styles
When to choose a Safety Exhaust Drain Valve
This valve is the right choice when you have a compressed air or pneumatic line that needs to be safely depressurized before service or downstream operations. Use it specifically when:
- Workers will open, disassemble, or service the downstream line. The most common application – prevents trapped pressure from injuring technicians.
- Your facility’s OSHA / safety policy requires controlled depressurization. This is the standard mechanical solution for that requirement.
- You want to remove the human-error risk of forgetting to bleed pressure before service.
- You need automatic operation with no electrical, sensor, or programming dependency – this valve uses pilot pressure only.
Comparison: Drain Valve vs Alternatives
| Approach | Manual ball valve | Solenoid-actuated dump valve | 22-XXX-4-11 Safety Exhaust |
|---|---|---|---|
| Vents trapped pressure | Only if operator remembers | Yes, when energized | Yes, automatically |
| Requires power/wiring | No | Yes | No |
| Fails safe on power loss | N/A | Depends on design | Yes (pressure release on loss) |
| Operator action required | Yes (every time) | Yes (sequence with shut-off) | None |
| Total cost | $10-50 + labor every cycle | $200-500 + wiring | $50-150, no recurring labor |
For most compressed air safety applications, the automatic drain valve gives you the safety benefit of a wired dump valve without the electrical complexity or installation cost. Contact Lance Valves if you need help sizing one for your specific system.
Frequently Asked Questions – Safety Exhaust Drain Valves
Q: What is a safety exhaust drain valve and what does it do?
A: A safety exhaust drain valve is an automatic valve installed on the downstream side of a shut-off valve in a compressed air or pneumatic system. When the upstream shut-off closes, the drain valve opens and vents trapped pressure to atmosphere. This prevents the unexpected release of stored pressure when a technician opens or services the downstream line.
Q: Why do I need one if I already have a manual ball valve?
A: A manual ball valve only stops flow – it doesn’t vent the pressure that’s already trapped downstream. Without a safety exhaust drain, that trapped air or gas remains at full system pressure until someone manually bleeds it. The drain valve does this automatically, removing the human-error risk from a routine task that can cause serious injury if missed.
Q: Where in the system should it be installed?
A: Install it immediately downstream of the primary shut-off valve, before any equipment or branch lines that need to be safely depressurized. The valve port should be plumbed to a safe vent location away from operators. Many installations use a short rigid pipe or a muffler to direct the vented air.
Q: What pressures and sizes does the 22-XXX-4-11 series support?
A: The 22-XXX-4-11 series is rated for compressed air systems up to standard industrial pressures. The valve is available in multiple port sizes to match your piping. For specific pressure ratings, flow coefficients, and port options, see the specification sheet linked at the top of this page.
Q: Does this require any electrical connection?
A: No. The safety exhaust drain valve is fully pneumatic. It uses pilot pressure from the system itself to stay closed during normal operation, and physics to open when that pilot pressure drops. No solenoid, no wiring, no programming.