Explosion test apparatus

The chemistry involved in this explosively unstable system is reviewed [1]. The mechanism of the trigger reactions that initiate the exothermic decomposition of chlorate-sulfur mixtures has been studied. Mixtures containing 1-30% of sulfur can decompose well below the m.p. of sulfur, and addition of sulfur dioxide, the suspected chemical trigger, causes immediate onset of the reaction [2], Autoignition of stoichiometric mixtures can be as low as 115°C, with frictional sensitivity at 5N, the lowest load the test apparatus permitted. Both were dependent upon the history of the sulphur used [3],... 

Figure 6-14 Test apparatus for acquiring vapor explosion data.

Test apparatus for acquiring dust explosion data. 

Two types of results are obtained from mechanical sensitivity tests (1) no reaction, or (2) decomposition with or without an explosion. The magnitude of friction and the impact sensitivity reported is the smallest load at which a positive result has been noted. The objective of mechanical sensitivity testing is to establish whether or not the substance is sensitive under normal handling conditions. However, this objective may not be reached. The test results may not truly reflect process conditions because most testing is carried out at ambient temperature and pressure. Since results are dependent on the type of test apparatus used, the interpretation of the results for use in practical applications requires much experience in this field of testing. 

The truly unnerving characteristic of HMTD was its sensitivity to friction. Earlier, the test apparatus used to determine friction sensitivity was briefly described. Usually, some form of pressure needs to be exerted on the wheel in order to create enough frictional force to initiate an explosive. In the case of HMTD, a sample could be placed on the plate and the wheel placed over it with no pressure exerted at all. The minute the plate was slid under the wheel, the HMTD detonated. 

J. Eadie, "The Effect of Wax on the Shock Sensitivity of Explosive Compacts , 4thONRSympDeton(1965), 399-403- Experiments were conducted using a "small gap test apparatus similar to that described in 1958 by Cachia Whitbread (See Ref 38). 

Impact Machines and Impact Tests. One frequently hears the remark that there are as many types of impact machines as there are explosives test laboratories. This is somewhat misleading. In reality, all laboratories use essentially similar equipment but test procedures, and test data analyses differ. Basically an impact machine is an apparatus that drops a steel weight from a pre-determined height onto a plunger or striker resting on top of the test sample which is placed on a steel anvil... 

The literature reports several types of impact testing apparatus also known as fall hammer apparatus , for the determination of impact sensitivity of explosives. 

A comparison of the impact sensitivity data of explosives reported by various teams from different laboratories suggests that the results obtained generally vary and it is due to (i) differences in the ways in which the experiments are conducted and (ii) use of different type of impact sensitivity apparatuses. However, when all influencing factors are considered, it appears that there is a similarity between the results obtained by different testing apparatuses. 

Brown, K. C. and Essenhigh, R. H., Dust Explosions in Factories A New Vertical Tube Test Apparatus. Safety in Mines Research Establishment Research Report, No 165, Ministry of Power, Sheffield, England (April 1959). 

The test apparatus consists of an explosion-proof water tank 10 m in diameter and 5m deep and a bridge and frame to support the sample and a pressure sensor. 

In the following, some examples for marking of explosion protected apparatus are given (the manufacturing companies are fictitious). It is assumed that these apparatuses have been manufactured, type tested and certified under the old article 100 directives (Table 3.6), applicable until 2003-06-30. 

In the following, type tests which are applied exclusively to firedamp-proof or explosion protected apparatus or which represent an enormous potential in material quality verification will be considered in more detail ... 

The shafts shall be tightened when entering the explosion chamber (1). This chamber shall withstand an explosion pressure of 1.5 MPa (=15 bar). Figure 8.12 shows a longitudinal section drawing of the spark test apparatus and Fig. 8.13 this apparatus in its entirety (cover of explosion chamber removed, however). 

Fig u re 8.13 Spark test apparatus, total view (cover of explosion chamber removed). 

For primer performance testing, primers are sealed in an air-tight test apparatus and initiated by dropping an 8 or 16 oz steel ball onto the primary explosive. Pressure transducers measure the output (Fig. 1.18c). 

The flame-test apparatus used at the US BurMines Explosives Experiment Station at Bruceton, Pa consists essentially of a cannon in which an explosive is fired or detonated. The cannon, identical widi that employed for the ballistic pendulum,ia mounts vertically on a concrete foundation located ia a dark building. By means of a photographic camera equipped with auitable devicea to cot off all extraneous light rays, the flame ia continuously obaetved such that its apex is in the field of view. The flame is recorded on a sensitixed film wrapped about a drum that revolves at a predetermined rate of speed. The length of each flame is indicated by its hei t in the photograph, and the duration by the length of photograph... 

This testing apparatus, which was first proposed by Audibert and Delmas, measures the tendency to -> Deflagration of a permitted explosive. A cartridge containing the test sample is placed, with its... 

If liquids act as thermal sinks to desensitize explosives, liquid nitrogen might be presumed to maximize the effect. Tests using a Picatinny Arsenal apparatus modified with the addition of a holder for the nitrogen indicate that of the primaiy explosives tested only dextrinated lead azide displays a decrease in impact sensitivity (Table VIII) [57]. 

H. J. Matsuguma, N. Palmer, J. V. R. Kaufman, Mechanical Parameters of the Picatinny Explosive Sensitivity Test Apparatus, in Proceedings of the International Conference on the Sensitivity and Hazards of Explosives, E. G. Whitbread, ed.. Explosives Research and Development Establishment, Waltham Abbey, Essex, England, 1963. 

The second test apparatus mentioned is used to determine the maximum explosion pressure and the maximum pressure rate. It is a spherical stainless steel autoclave of 20 liters volume. Dust samples of up to 40 g per trial, covering a concentration range of up to 2 kg/m, are blown into the sphere through special ring nozzles. The dispersed dust is ignited with varying delay time. The pressxue/time-history is measured. The maximum pressure rate observed is transferred into the safety number Kst value with the help of the so-called cubic-root-law. 

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