Grain Bucket Elevators

Challenge

The first challenge is to prevent a deflagration in either the head or boot portion of a grain elevator from spreading quickly through either leg of the elevator to surrounding equipment. The second challenge is to use an environmentally-friendly agent capable of protecting both people and facilities against the devastation of a runaway explosion.

Application

The X-PAC III Grain Elevator Protection System is a cost-effective solution to the explosion risk associated with grain bucket elevators. Explosion protection systems are a suitable approach for protecting grain elevator legs handling bulk raw grain per NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities. The X-PAC III offers a significant advantage over vented elevator legs by providing explosion isolation extinguishers on the elevator inlet chutes, discharge chutes, and dust extraction lines. Isolation extinguishers mitigate the propagation of explosions to connected equipment where devastating secondary explosions can occur. This is a particularly important consideration for elevators feeding the main grain storage silos.

Description

The X-PAC III system consists of EX 200TM control units and four types of devices mounted on the bucket elevator. These are the Detector-Extinguisher Unit, the Extinguisher Unit, the Duct Isolation Unit, and the Shutdown Detector. Each device has a steel frame for mounting onto the bucket elevator. The Duct Isolation Unit is equipped with a flexible hose for mounting onto a dust extraction line. Typically, separate protection zones are provided for the elevator head and elevator boot. Upon detection of a deflagration, the extinguishers within that zone discharge DuPont FE-25TM suppressant into the process. Simultaneously the EX 200 control unit initiates shutdown of the process and activates an alarm.