1、Designation: E144 94 (Reapproved 2011)Standard Practice forSafe Use of Oxygen Combustion Bombs1This standard is issued under the fixed designation E144; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThe warning note was editorially moved into 4.1 in December 2006.1. Scope1.1 This practice covers methods for judging the soundnessof new and u
3、sed oxygen combustion bombs, and describes theprecautions to be observed in oxygen bomb combustionmethods.1.2 This practice is applicable to all procedures in whichsamples are completely oxidized by combustion in a metalbomb containing oxygen under pressure. Where there isconflict with specific prec
4、autions in individualASTM methods,the latter shall take precedence.1.3 The values stated in inch-pound units are to be regardedas the standard. The metric equivalent of inch-pound units maybe approximate.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with
5、 its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Physical Requirements2.1 Initial TestThe manufacturer of oxygen combustionbombs for use in ASTM test methods
6、 shall furnish a certificatewith each new bomb showing that it has satisfactorily passedthe hydrostatic and proof tests described in Sections 3 and 4.When requested, the manufacturer shall supply evidence thatthe bomb is designed and constructed in accordance withrecognized practices for pressure ve
7、ssel equipment.2.2 Periodic InspectionAll seals and other parts that arerecommended by the manufacturer shall be replaced or re-newed after each 5000 firing or at a more frequent interval ifthe seals or other parts show evidence of deterioration. Thehydrostatic and proof tests described in Sections
8、3 and 4 shallbe repeated if any of the following have occurred:2.2.1 Five thousand firings.2.2.2 Firing with an excessive charge of either sample oroxygen.2.2.3 Ignition of any internal part of the bomb, includingfuel capsule.2.2.4 The evidence of corrosion or surface defects whichexceed 80 % of the
9、 manufacturers stated corrosion allowancefor the bomb.2.2.5 Any change in thread tolerances of bomb enclosureswhich exceed the manufacturers specifications.3. Hydrostatic Test3.1 Fill the bomb with water at room temperature andconnect to a suitable hydraulic pressure system. Be sure that allair has
10、been displaced from the bomb and from the connectinggas passages. Support the bomb so that the diameter at themidsection of the cylinder can be measured with a micrometercaliper, and the deflection at the center point of the bottom canbe measured with a micrometer dial indicator. Apply waterpressure
11、 which is 1.5 times the manufacturers recommendedworking pressure test pressure of the bomb and check the bomband pressure connections for leaks.3.2 With the hydraulic system at atmospheric pressure,measure the diameter at the midsection of the cylinder andobtain a zero reading for the dial indicato
12、r in contact with thecenter point of the bottom of the bomb. Raise the hydrostaticpressure to test pressure and repeat these measurements, thenrelease the pressure and take a third set of measurements withthe system at atmospheric pressure. If the application of testpressure produces a deflection gr
13、eater than 0.005 in. (0.127mm) at the midsection of the cylinder or at the center point ofthe bottom of the bomb, or if any of the bomb parts do notresume their original dimensions when pressure is released,reject the bomb as unsafe.4. Proof Test4.1 Record the outside diameter at the midsection of t
14、hebomb cylinder as measured with a micrometer caliper, thenassemble the bomb for firing with a tablet or pellet ofcompressed benzoic acid that gives an energy release that is 1.5times the manufacturers recommended energy release limit.Admit oxygen slowly to an initial pressure that represents theman
15、ufacturers maximum charging pressure, then submergethe bomb in water and check for gas leaks. If none appear,arrange the bomb for firing in a water bath protected by a heavy1This practice is under the jurisidiction of ASTM Committee E41 on LaboratoryApparatus and is the direct responsibility of Subc
16、ommittee E41.01 on Apparatus.Current edition approved Dec. 1, 2011. Published December 2011. Originallyapproved in 1959. Last previous edition approved in 2006 as E144 94 (2006)e1.DOI: 10.1520/E0144-94R11.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
17、2959, United States.barricade. (WarningThis is a proof test with a twice-normalcharge, therefore the operator must be fully protected (5.1.4)incase the bomb should rupture when fired.)4.2 Fire the bomb and allow it to stand for 10 min whilecooling water is circulated through the bath. Remove the bom
18、b,release the residual pressure, open and examine the parts, alsomeasure the diameter at the midsection of the cylinder. If anyof the bomb parts do not resume their original dimensions afterthis test, reject the bomb as unsafe.5. Precautions in Use of Bombs5.1 Observe the following precautions in al
19、l oxygen bombcombustion methods:5.1.1 Sample WeightThe total weight of combustiblematerial (sample plus gelatin, firing oil, or any other combus-tion aid) shall not exceed the maximum energy release recom-mended by the manufacturer. Initial tests with new materialsthat might be expected to burn rapi
20、dly, or to have explosivecharacteristics, shall be conducted with caution using only afraction of the allowable maximum sample.5.1.2 Oxygen Filling SystemThe oxygen filling systemshall include a pressure regulator or other automatic device toprevent overcharging beyond the maximum allowable pressure
21、specified in the appropriate ASTM test method. There must beno oil or other combustible materials in this system. Check thepressure gauge or gauges for accuracy at regular intervals, orwhenever there is any reason to suspect that they are inaccu-rate. The bomb must not be fired if an over-charge of
22、oxygenshould accidentally be admitted.5.1.3 Ignition SystemThe bomb must be completely sub-merged in water during firing, and the charge must not beignited if there is any evidence of gas leakage. Draw theignition current from a stepdown transformer or from a suitablebattery, using the lowest practi
23、cable voltage recommended bythe manufacturer. Control the circuit by a double-pole pushswitch that can be closed only when the operator presses theignition button.5.1.4 Safety BarricadeProtect the operator by a barricadewhen firing the bomb and for 15 s thereafter. The barricadeshall consist of14)-i
24、n. (6.35-mm) steel plate or other equivalentprotective material.6. Keywords6.1 bombs; combustion; oxygenASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that
25、determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapprove
26、d or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel
27、 that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual repri
28、nts (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E144 94 (2011)2
