Ignition means

Ignition means Method employed to ignite a deflagration train of explosions of pyrotechnic substances (e.g., a primer for propelling a charge, an igniter for a rocket motor, or an igniting fuse). 

Core designation County Depth of sample(m) Mean loss on ignition Mean total carbon content... 

A new E-glass roving gives fast wet-out with polyester, vinyl ester, epoxy, phenolic, urethane, and furan resin systems, due to low sizing content. Low loss on ignition means that there is not an excessive amount of sizing to be broken down by the styrene in the resin. 

Product characterization aims at defining their end-use properties by means of conventional standard measurements related as well as possible — and in any case, being the object of a large consensus— to end-use properties. We cite for example that octane numbers are supposed to represent the resistance of gasoline to knocking in ignition engines. 

In the former, it gives precipitates with halides (except the fluoride), cyanides, thiocyanates, chromates(VI), phosphate(V), and most ions of organic acids. The silver salts of organic acids are obtained as white precipitates on adding silver nitrate to a neutral solution of the acid. These silver salts on ignition leave silver. When this reaction is carried out quantitatively, it provides a means of determining the basicity of the acid... 

Ether. The most satisfactory method for the removal of (diethyl) ether is either on a steam bath fed from an external steam supply or by means of an electrically-heated, constant-level water bath (Fig. 77, 5, 1). If neither of these is available, a water bath containing hot water may be used. The hot water should be brought from another part of the laboratory under no circumstances should there be a free flame under the water bath. It caimot be too strongly emphasised that no flame whatsoever may be present in the vicinity of the distillation apparatus a flame 10 feet away may ignite diethyl ether if a continuous bench top lies between the flame and the still and a gentle draught happens to be blowing in the direction of the flame. 

Recent developments in rotary atomization include the use of semiconductive composites (qv) for the rotary cup permitting the constmction of a unit that does not produce an ignition spark when brought close to a grounded workpiece yet has the transfer efficiencies associated with a rotary atomizer. In addition, the use of the semiconductive material softens the electrostatic field and results in less edge buildup and better penetration into recess areas. Other systems use electronic means to effectively prevent arcing to grounded surfaces. 

The fundamental parameters in the two main methods of achieving ignition are basically the same. Recent advances in the field of combustion have been in the development of mathematical definitions for some of these parameters. For instance, consider the case of ignition achieved by means of an electric spark, where electrical energy released between electrodes results in the formation of a plasma in which the ionized gas acts as a conductor of electricity. The electrical energy Hberated by the spark is given by equation 2 (1), where V = the potential, V 7 = the current. A 0 = the spark duration, s and t = time, s. 

Most of the commercial gas—air premixed burners are basically laminar-dow Bunsen burners and operate at atmospheric pressure. This means that the primary air is induced from the atmosphere by the fuel dow with which it mixes in the burner passage leading to the burner ports, where the mixture is ignited and the dame stabilized. The induced air dow is determined by the fuel dow through momentum exchange and by the position of a shutter or throtde at the air inlet. Hence, the air dow is a function of the fuel velocity as it issues from the orifice or nozzle, or of the fuel supply pressure at the orifice. With a fixed fuel dow rate, the equivalence ratio is adjusted by the shutter, and the resulting induced air dow also determines the total mixture dow rate. 

Fig. 2. Effect of mixture strength on exhaust gas composition (dry basis) and brake specific fuel consumption (BSFC) for an unsupercharged automotive-type engine usiag iadolene fuel, H/C = 1.86, where the ignition is tuned to achieve maximum best torque (MBT), the brake mean effective...

Eliminate turned-down vents from safety relief valves, i.e., upside down U. Possible accidental ignition of releases from such vents wiU likely result in flame impingement on the top external surface of the tank, above the internal wetted surface. BLEXT Some means to handle rainwater from a desirable upward vertical vent have been listed by Bodurtha (ibid., April 1988). Moreover, a safety relief valve must function properly when required and must be sized properly to help prevent an explosion. 

Static charge generation causes an ignition hazard only if the accumulated charges create an electric field sufficient to produce an electrical discharge in a flammable atmosphere. In most processes, this means that the electric field intensity at some location must reach the breakdown strength of air (nominally 3 X lO " V/m). The objective of static-control measures is to ensure that electric field intensities cannot reach this value. 

---