Interlock System Design Key Point
An air‑lock chamber (blast‑proof buffer airlock) serves as a critical pressure‑isolation passage for chemical hazardous‑material laboratories, blast‑resistant control rooms and explosion‑proof compartments. The core objective of the double‑leaf mechanical manual interlock is physical hard constraint: the two doors shall never be unlocked and opened simultaneously. At least one door leaf shall remain pressure‑tight at all times to block blast shock waves and prevent cross‑region leakage of toxic and flammable gases, thus stabilizing the air‑tight pressure differential inside the chamber. Requiring no electrical, pneumatic or hydraulic supplies, the pure‑mechanical interlock can operate reliably under power‑failure, blast‑impact, high‑temperature and dusty conditions, making it the preferred solution for high‑risk working conditions.
Transmission Connecting Rod and Shift Fork
Materials: Q345B alloy steel or 304 stainless steel are preferred. 316L stainless‑steel shall be adopted for chemical corrosive environments. Ordinary Q235 is not recommended to avoid jamming caused by rusting.
Return Spring
Spring force shall balance the frictional resistance of the mechanism. Insufficient spring force will lead to incomplete reset and interlock failure. Excessive spring force will result in excessive manual operating torque.
Coordination with Multi‑point Explosion‑proof Latching System
Under anti‑blast impact conditions, the interlock mechanism shall not be falsely unlocked when blast shock‑wave acts on the door leaf. Impact stops shall be equipped to bear impact loads.
Collaborative Design of Sealing System
The interlock only realizes operation mutual‑exclusion. Airtight performance depends on the full‑perimeter sealing gaskets of the door leaf.
Key Points for Manufacturing, Commissioning and Acceptance
Factory commissioning: Perform repeated cyclic opening‑closing tests. Simulate mis‑operation: forcibly rotate the inner‑door handle while the outer door is unlocked; the inner door shall be fully locked and cannot be unlocked. Carry out verification in the reverse direction likewise.
Clearance inspection: Check the fit of moving pairs with a 0.1 mm feeler gauge; no excessive play shall exist. All moving components shall operate without jamming.
Escape‑function verification: Personnel inside the chamber shall be able to open the door for emergency evacuation normally without interlock restriction.
Combined air‑tightness test: Open and close the two doors in sequence to verify pressure‑holding performance and confirm no pressure short‑circuit caused by simultaneous opening of both doors.
Durability test: Retest the interlock function after no less than 5 000 operating cycles. No jamming or functional failure shall occur.
Maintenance interfaces: Reserve lubrication grease nipples. An access cover shall be fitted on the mechanism lock box for regular maintenance. The mechanism can be disassembled for overhaul without removing the entire door leaf.
