1、Designation: E95 68 (Reapproved 2011)Standard Specification forCell-Type Oven with Controlled Rates of Ventilation1This standard is issued under the fixed designation E95; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the general requirements of acell-type oven with controlled rates of ventilation for deter-
3、mining loss in weight or changes in properties of materials onheating at elevated temperatures. These specifications take intoaccount the fact that chamber geometry, rate of ventilation, andtemperature each affect the rate of loss of volatile constituentsfrom a material, or the rate of change in oth
4、er properties. Thisoven is recommended whenever the results are dependent onthe time and temperature of heating, the amount of ventilation,or both. It is assumed that specific requirements such asspecimen shape and dimensions, rate of ventilation, time, andtemperature will be included in the applica
5、ble material speci-fications or test methods.NOTE 1Ovens meeting these specifications have been found usefulfor determination of plasticizer loss in plastics, and for controlled aging ofelastomers and plastics.1.2 The values stated in inch-pound units are to be regardedas the standard.2. Referenced
6、Documents2.1 ASTM Standards:2D1870 Practice for Elevated Temperature Aging Using aTubular Oven3. Types3.1 Ovens are classified according to ventilation rate withinthe cells, provision being made for low (LV) and high (HV)ventilation rates. Thus, for materials showing low rates ofweight loss a means
7、is provided for their evaluation without thenecessity of providing the excessive heat input required by thehigher ventilation rate. It should, however, be established byexperiment when using the LV-type oven that the rate ofventilation is adequate to avoid stagnation at the surface of thespecimens,
8、as would be caused, for example, by high rates ofdiffusion of volatile constituents through the body of thespecimen.3.2 Oven types are classified as follows:Type Ventilation Rate, m/minLV 0.25 to 25HV 100 to 2504. Requirements4.1 The oven shall consist of one or more cylindrical cells,each having a
9、minimum diameter of 35 mm (1.4 in.) and aminimum length of 300 mm (12 in.). The cells shall bemounted in a thermostatically controlled, heat-transfer me-dium: for example, an aluminum block, a liquid bath, or acirculating-air oven. The cells shall not be constructed ofcopper or a copper alloy.4.2 Th
10、e design of the oven shall be such that heated airenters one end of the cell and is exhausted from the other endof it without being recirculated. In order to prevent cross-migration of volatile constituents contained in the specimensbeing tested, air passing over a specimen in one cell shall notcome
11、 in contact with specimens in other cells.4.3 Air entering the cells shall have been filtered andpreheated to within 1C of the specified temperature for thespace occupied by the specimen. The design shall also permitthe cells to be cleaned easily after each test.4.4 Provision shall be made for meter
12、ing the airflow througheach cell within 610 % of any desired rate within the range ofthe particular type of oven. The air may be metered to eachtube, or a single pressure-control device leading to a plenumchamber may be used. If a plenum chamber is used, cellsshould be connected to it by passageways
13、 or orifices havingrestrictions to assure the same rate of airflow to each cell. Therate of flow may be measured on the entering air at roomtemperature, if the proper factor is applied for the increase inrate of flow caused by the thermal expansion of the air when itis raised to the temperature of t
14、he cell.4.5 Provision shall be made for supporting and positioningspecimens within the cell, separated from each other andwithout touching the walls of the cell.NOTE 2Only one specimen should be mounted in each cell unless itis known that the inclusion of additional specimens would not affect the1Th
15、is specification is under the jurisdiction of ASTM Committee E41 onLaboratory Apparatus and is the direct responsibility of Subcommittee E41.01 onApparatus.Current edition approved Dec. 1, 2011. Published December 2011. Originallyapproved in 1952. Last previous edition approved in 2006 as E95 68 (20
16、06). DOI:10.1520/E0095-68R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 1
17、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.result. The specimens and specimen supports should not occupy more than25% of thecross-sectional area of the cell.4.6 The temperature in the space occupied by the specimenshall be controllable within 1C of any specifi
18、ed temperaturewithin the range of 50 to 150C. The assumption should not bemade that the temperature of individual cells is the same as thetemperature of the heating medium, or that the temperature ofall cells is alike simply because they are immersed in the sameheating medium. Differences in cell te
19、mperatures may resultfrom differences in the rate of airflow, in the temperature of airentering the cells, or in the temperature at various locations inthe oven. It is recommended that the temperature in the spaceFIG. 1 Type HV Cell-Type OvenE95 68 (2011)2occupied by the specimen be verified by mean
20、s of thermo-couples, care being taken to avoid heat loss along thermo-couple lead wires.5. Design5.1 The design of the oven is optional provided it complieswith the requirements of 4.1-4.6, inclusive. One design thatconforms to these requirements is shown in Fig. 1. Anotherdesign is shown in the app
21、endix of Practice D1870.6. Keywords6.1 cell-type; controlled rates of ventilation; ovensREFERENCES(1) Marks, M. E., “Method for Weight Loss of Plastic Films and Sheets onHeating,” ASTM Bulletin, No. 159, July, 1949, p. 53.(2) Journal, Society Chemical Industry, January, 1947.(3) Industrial and Engin
22、eering Chemistry, Vol 35, 1943, p. 896.(4) Journal Scientific Instruments, Vol 11, 1934, p. 10.ASTM 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 determina
23、tion 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 reapproved or with
24、drawn. 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 that you
25、r 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 reprints (sing
26、le 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/).E95 68 (2011)3
