Mechanical sparks

Tramp metal Provide suitable protection (e.g., magnetic separa-reaching mill tors, screens, etc.) resulting in fric-, Secure all potential sources of tramp metal (e.g., tional heat- fasteners etc.) in upstream equipment ing/mechanical spark which pro- enclosed feed systems, not operator fed vides an ignition system source. CCPS G-23 CCPS G-29 CCPS G-34... 

During the test, hydrogen flow rate was raised to a maximum of approximately 55 kg/s (120 Ib/s). About 23 seconds into the experiment, a reduction in flow rate began. Three seconds later, the hydrogen exploded. Electrostatic discharges and mechanical sparks were proposed as probable ignition sources. The explosion was preceded by a fire observed at the nozzle shortly after flow rate reduction began. The fire developed into a fireball of modest luminosity, and an explosion followed immediately. 

Bruderer, R. E., Ignition Properdes of Mechanical Sparks and Hot Surfaces in Dust-Air Mixtures, Ibid., p. 152. 

Sprayed water wets equipment and could reduce the probability of a mechanical spark developing. 

Does the proposal introduce a source of ignition (including hot surfaces, flame, mechanical sparks, static electricity, electrical arcing, etc.) ... 

Either decrrical or mechanical sparks can easily cau.se the ignition of flammable vapors. A relatively small a-... 

Frictions and Impacts. Friction produces hot surfaces and emits small luminous objects called mechanical sparks, both of which can ignite flammable gases. Impact can cause friction between the two surfaces. Impact without friction can cause ignition of shock sensitive materials. 

Friction and impact are complex mechanical processes at the surfaces where a portion of the kinetic energy is converted to heat. Whether a mechanical spark will be incendive toward a flammable gas is determined on a number of factors, which include ... 

The elimination of ignition sources such as hot surfaces, flames, hot gases, mechanical sparks, electrical installations, static electricity or exothermic reactions, is looked upon as preventive to a limited extent only. In former times this measure was rated secondary. 

More in-depth analysis of the mechanism can be found in other reviews. The reaction and proposed mechanism sparked a considerable amount of interest in this type of system. Zamaschikov and co-workers prepared the alkyl platinum(iv) intermediate, [CUPtR] (R = CH3, CH2CH3, and CH2C(0)CH3>, and monitored the kinetics of decomposition to form R-Cl and R-OH. Subsequent studies by Bercaw and co-workers revealed that the R-X bond forming step proceeds via an SN2-type mechanism. ... 

The minimum ignition energy (ME) is a parameter forjudging the incendivity by important sources of ignition such as electrostatic discharge and mechanical spark. It represents the smallest possible amount of energy capable of just igniting the most flammable gas/air or vapour/air mixture in such a way that a flame occurs... 

Mechanical sparks By friction, impact or grinding particles can be separated from solid materials. Their temperature can be high due to the energy absorbed in the separation process. If the particles consist of Limitation of the relative velocity to <1 m/s... 

By monitoring sources of ignition which may arise although not present during normal operation such as heated parts or mechanical sparks a reaction in critical situations becomes possible. 

The heat leg can be controlled with common sense measures to stay away from heat sources. Here are some examples of heat sources open flames, smoking, static electricity, cutting and welding, hot surfaces, electrical and mechanical sparks, and lightning. The heat leg can also be controlled by the use of a flame arrester, discussed later in this article. 

Mechanical sparks and friction. Sparks and local heating caused by friction or impact between two metal surfaces or between a metal surface and foreign objects inadvertently introduced into the plant have been known to ignite dust clouds. 

Electrical, sparking equipment Mechanical, sparking equipment Electrostatic charge... 

Control of Mechanical Sparks and Friction. Foreign materials (such as tramp metal) that are capable of igniting combustible material being processed should be removed from the process stream by magnetic separators, pneumatic separators, or grates or other separation devices. 

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