Porous explosion proof mouldings made from abrasives - are used as flame trap sleeves on gas detectors or as fuses in safety appts.

摘要

Material for mfg. explosion proof sleeves consisting of a porous body or moulding permeable to gas, the material being an abrasive with Mohs' hardness >=6. The abrasive is pref. electrocorundum and/or boron carbide and/or SiC and/or corundum. The abrasive is pref. used to make housings for an element which can create an explosion in a medium, esp. (a) a current limiting resistance; (b) a thermistor or pisistor used in a sensor or explosive media in gas analysis appts.; (c) a fuse. The sleeve or housing is pref. made from a mixt. of fine abrasive grains and a binder which burns below the m.pt. of the abrasive; the mixt. is moulded under press., then heated to sinter the abrasive and burn out the binder, leaving a porous moulding. The binder is pref. a mixt. of starch, feldspar and clay. Used for safety devices in coal mining or the chemical-, gas-, petroleum-, or other industries.