Home>ASTM Standards>ASTM F433-02(R2020) pdf free download

ASTM F433-02(R2020) pdf free download

ASTM F433-02(R2020) pdf free download.Standard Practice for Evaluating Thermal Conductivity of Gasket Materials
1. Scope
1.1 This practice covers a means of measuring the amount of heat transfer quantitatively through a material or system. 1.2 This practice is similar to the Heat Flow Meter System of Test Method C518, but modified to accommodate small test samples of higher thermal conductance. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
N OTE X2.2—If there is no contact resistance, δ, Eq X2.4 goes to zero and the Eq X2.12 assumes the same form as Eq X2.2. Also, note that the calibration data, subscript r, needs to be obtained only once at each temperature level. Thermocouple readings may be kept in mV and need not be converted to °C (°F) except for determining the average sample temperature.) X2.1.8 Ifan analog calculator is used to obtain the unknown sample k-factor and thermocouples are installed in the sample surface: The ∆T signal is then obtained by connecting the thermocouples differentially; the HFT and ∆T signals are amplified and divided electronically with the results shown on a digital volt meter (Fig. 4). The gain of the final stage amplifier can be varied to produce an output voltage equal to the thermal conductance of the sample in any desired set of units. In other words, if the thermal conductance, (C = k⁄∆x), of the sample is 15 Btu/h·ft 2 ·°F, the output voltage of the analog calculator is 15 V. The k-factor is obtained by multi- plying the displayed value by the sample thickness, ∆x, measured separately.
X2.1.11 A calibration run must be made first to obtain the correct value for α and to adjust the final gain for the proper C-factor. The reference sample must have thermocouples installed in grooves in the surface. After these thermocouples have been connected to the ∆T input of the calculator and the correction constant α has been adjusted to zero (see Fig. 5). The final gain must be adjusted to obtain the correct C-factor of the reference sample. Next, the permanent thermocouples are connected to the ∆T channel of the calculator and the correc- tion constant α adjusted until the displayed C-value is the same as before. Subsequent tests on unknown samples without thermocouples yield the correct C-factor directly on the digital display. Multiplying these C-factors by the corresponding sample thickness gives the k for each case.
X3.2 The device referred to is described as a heat-insulated copper vessel with a heavy copper plate base, and a receiver containing a mating copper plug which is also insulated. While the upper plate or vessel and test sample is at a constant temperature, heat flow through the sample is produced by measuring the slowly changing temperature increase of the receiver with thermocouples. The rate of flow of heat through the specimen is proportional to the area and the ∆Tofthe faces of the specimen, and inversely proportional to the thickness. This fixture is recommended for use at 100°C (212°F) hot-side temperature; however, testing at 150°C (302°F) can be done with a non-petroleum type heat transfer fluid 6 when the bath temperature is controlled by use of a thermoregulator and electronic relay in conjunction with the immersion heater. Included with this device is a copper vessel source, heat- insulated on the sides, a receiver with an insulated copper plug face ground, a galvanometer, an immersion heater, a weight, 5 kg (11 lb), a micrometer, a stop watch, an electronic relay, and a thermoregulator.

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