How PSD Doors Work
Enhanced actuation response, at very low opening pressures, from our Patented and accurate pressure release system

Patented spring-loaded latching system provides superior performance.


The key to the PSD explosion relief door is the action of the door panel which triggers a unique pre-loaded magnet and spring-loaded latching system for fast opening.  (United States Patent 4,207,706)


Built directly into the door itself, the latching assembly opens when a preset pressure is achieved.


The door panel uses a very rigid, lightweight honeycomb interior structure securely bonded to sturdy exterior metal skins. 


The overall vent panel density (defined in NFPA 68 "Standard on Explosion Protection by Deflagration" in Kg/m2 to compare against the mass threshold Mt) varies with the choice of honeycomb, metal skins, latch bars and overall size. Please contact us to estimate this vent panel density.


Because of the door’s strength, it deflects uniformly when activated, providing pressure relief over its entire area. 


Because this rigid door also floats on springs, it uniformly compresses the flexible gasket seals between it and the rigid door frame.


The lightweight, low inertia door, coupled to the pre-loaded spring and magnetic latch provides millisecond response time to open. As a result, PSD explosion relief doors are exceptionally effective for high pressure pulses (dp/dt).

The key to the simple and reliable operation of the PSD explosion relief door is the proprietary, patented latch and actuator system.


Under normal conditions, the rectangular magnet (left) is set in the closed position (above) against the latch handle, pulling the latch bar down to compress the springs. This latching action transfers a uniform spring load to the door panel, compressing the door seals.


Under overpressure conditions, the door panel deflects uniformly, overcoming the spring preload. This deflection moves an actuator set screw in the latch bar arm, disconnecting a magnetic target from the permanent magnet.


Once disconnected from the magnet, pressure from both the springs and the overpressure on the door allows the latch handle to revolve, releasing the door.


Because of the strength of the honeycomb structure, the entire door moves as an unit, releasing all the latches simultaneously. 

The PSD explosion relief door is preset to open at any set point from 4" to 24” WC +/- 2” (0.145 psig to 0.865 psig +/- 0.07 psig or 102 mm to 610 mm +/- 51 mm water). This low pressure sensitivity is very difficult to achieve with most other explosion relief devices. And, because the PSD door opens at these lower pressures, it requires less minimum opening area, relieving potentially dangerous situations earlier.

Unlike scored or formed membrane systems from competitors (Fike, CV Technology, BS&B, REMBE and others) which, by design, are much more sensitive to overpressure at their center than their perimeters, PSD doors are equally sensitive across the entire rigid surface, utilizing the full surface area for pressure relief.


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