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1、BRITISH STANDARD BS 1902-5.5: 1991 Methods of testing Refractory materials Part 5: Refractory and thermal properties Section 5.5 Determination of thermal conductivity (panel/calorimeter method) (method 1902-505) Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontro
2、lled Copy, (c) BSI BS 1902-5.5:1991 This British Standard, having been prepared under the direction of the Refractory Products Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 30 August 1991 BSI 08-1999 The following BSI references relate
3、to the work on this standard: Committee reference RPM/1 Draft for comment 89/41860 DC ISBN 0 580 19640 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Refractory Products Standards Policy Committee (RPM/-) to Technical Committee RPM/1,
4、 upon which the following bodies were represented: British Ceramic Research Ltd. British Steel Industry Engineering Equipment and Materials Users Association Refractories Association of Great Britain Refractory Contractors Association Society of Glass Technology Amendments issued since publication A
5、md. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 BSI 08-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Designation1 3Definition1 4Principle1 5Apparatus1 6Test panel6 7Proc
6、edure7 8Calculation of thermal conductivity9 9Test report10 Figure 1 Vertical section through thermal conductivity apparatus3 Figure 2 Horizontal section, showing arrangement of heaters3 Figure 3 Basic circuit for heater control system4 Figure 4 Design of calorimeter and guard ring5 Figure 5 Arrange
7、ments for measurements in different dimensions7 Figure 6 Corresponding positions of thermocouples for arrangements in Figure 58 Table 1 Resistance wire for heaters4 Table 2 Specific heat capacity of water10 Publication(s) referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri N
8、ov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 ii BSI 08-1999 Foreword This Section of BS 1902-5 has been prepared under the direction of the Refractory Products Standards Policy Committee. The method described in this Section is one of three methods for the determination
9、 of thermal conductivity included in BS 1902-5, as follows. Section 5.5: Determination of thermal conductivity (panel/calorimeter method) (method 1902-505); Section 5.6: Determination of thermal conductivity (hot wire method) (method 1902-506); Section 5.8: Determination of thermal conductivity (spl
10、it column method) (method 1902-508)1). This Section of BS 1902 is a revision of the method previously included in BS 1902-1A:1966 (obsolescent), which is withdrawn. NOTEThis Section is to be read in conjunction with BS 1902-5.0 “Introduction” and BS 1902-3.1 “Guidance on sampling”. Section 5.0 sets
11、out the general arrangement of BS 1902 and lists the Sections of Part 5. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer i
12、mmunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in
13、 the amendment table on the inside front cover. 1) In preparation. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 BSI 08-19991 1 Scope This Section of BS 1902-5 describes the panel method for determining the thermal conduct
14、ivity of dense shaped and shaped insulating refractory products by a continuous flow calorimeter method. The panel/calorimeter method may be used for preformed unshaped products and for ceramic fibre products. NOTE 1For details of the adaptations needed for ceramic fibre products, see BS 1902-6. The
15、 panel/calorimeter method is intended for materials having a thermal conductivity in the range 0.5 W/(mK) to 20 W/(mK) and hot face temperatures in the range 300 C to 1 400 C. For thermal conductivities below 0.5 W/(mK) see BS 1902-5.6. NOTE 2The titles of the publications referred to in this standa
16、rd are listed on the inside back cover. 2 Designation The method of determining thermal conductivity by the panel/calorimeter method described in this Section is referred to by the designation: Method 1902-505 3 Definition For the purposes of this Section of BS 1902, the following definition applies
17、. thermal conductivity (coefficient of thermal conductivity), 2, (in W/(mK) the rate of linear heat flow, under steady state temperature conditions, through unit area of a test piece, per unit temperature gradient in a direction perpendicular to the area 4 Principle The quantity of heat flow unidire
18、ctionally through a test panel, heated on one face under controlled temperature conditions, is measured using a continuous flow water calorimeter. 5 Apparatus 5.1 General The apparatus consists of a furnace in which a system of heaters is used to induce a uniform, unidirectional heat flow through a
19、test panel under stable temperature gradient conditions. A continuous flow water calorimeter with guard ring is used to measure the rate of flow of heat through the test panel. 5.2 Furnace, comprising a chamber, which accommodates a test panel 230 mm 230 mm 76 (or 64) mm deep, and a heater well nomi
20、nally 214 mm 214 mm 58 mm deep formed from shaped insulating refractory (see Figure 1). The walls and floor of the heater well are formed of 25 mm thick insulating refractory, of class 150, complying with BS 7225-1.1. The walls of the heater well are lined with 8 mm thick, 50 mm deep alumino-silicat
21、e refractory plates (60 % to 65 % Al2O3) which stand on a 230 mm square, 8 mm thick base of the same material. The wall plates which act as a support for the test panel are pierced with 16 mm holes at 25 mm centres to accommodate the end of the main and side heater elements. Behind the walls a narro
22、w chamber, which accommodates the outer heater and lower peripheral heater, is formed on the inside from 8 mm thick alumino-silicate refractory (60 % to 65 % Al2O3) and on the outside from 25 mm thick insulating refractory of class 150, complying with BS 7225-1.1. The remainder of the brickwork surr
23、ounding the heater well and test panel chamber is made of insulating refractory of class 130, complying with BS 7225-1.1, with a final 76 mm thickness of lower temperature insulation, e.g. diatomite brick, to give overall furnace dimensions of 690 mm 690 mm 380 mm height. The furnace is encased in s
24、heet metal, and supported in a steel frame, e.g. angle iron. NOTEAlternate holes may be extended into vertical grooves to facilitate the removal of the heaters, as shown in Figure 2. The upper and middle peripheral heaters and a supplementary heater, consisting of coiled electrical resistance wire (
25、see 5.3), are laid in grooves cut in the insulating refractory. The upper and middle peripheral heaters are positioned 12 mm and 38 mm below the top level of brickwork and 33 mm behind the wall of the test panel chamber on all four sides. The supplementary heater is 50 mm below the base of the heate
26、r well and laid in a continuous groove having the form of a parallel-sided spiral covering an area of approximately 310 mm 310 mm. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 2 BSI 08-1999 5.3 Heaters, in which the eleme
27、nts of the main, side, outer and lower peripheral heaters are formed from platinum 20 % rhodium wire, 0.5 mm in diameter, wound on recrystallized alumina tube with 12 mm outside diameter, 8 mm inside diameter (see Figure 1 and Figure 2). The six elements forming the main heater unit are wound with d
28、ifferent spacing, being more closely wound at the edge of the unit than at the centre. The two end elements (1 and 6 in Figure 2) are wound with a 5 mm spacing, the next two inside elements (2 and 5 in Figure 2) are wound with a 5 mm spacing at the ends with a 7.5 mm spacing over the middle 114 mm a
29、nd the two centre elements (3 and 4 in Figure 2) are wound with a 7.5 mm spacing over their full length. The elements of the side and outer heaters are wound with a spacing of 3.8 mm to 4.0 mm and those of the lower peripheral heaters with a spacing of 3.3 mm to 3.5 mm. The individual elements of th
30、e main, side, outer and lower peripheral heaters are connected in series and are thinly coated with high purity alumina cement to reduce volatilization of the platinum at high temperature. The upper and middle peripheral heaters and the supplementary heater are each formed by coiling electrical resi
31、stance wire 1.6 mm in diameter on a steel former 4.5 mm in diameter. The two peripheral heaters are drawn out to 12 or 13 turns for 25 mm. The gauge of wire, coil spacing and resistance data for all heaters is summarized in Table 1. 5.4 Power supply and temperature control, allowing each heater to b
32、e separately controllable. Various methods for achieving adequate control of heater output are available including variable resistance, variable transformers and integrated circuit power controllers. A suitable control system utilizes solid state, phase-controlled, a.c. mains power regulators switch
33、ed between adjustable low and high power settings by a single temperature controller operating through one of the hot face thermocouples (see clause 6). The basic circuit for an appropriate control system is shown in Figure 3. 5.5 Calorimeter and guard ring, made of brass and having dimensions as sh
34、own in Figure 4. The base, sides and partition walls of both components are made either by casting or by machining from solid brass. The outside surfaces of the sides and base and the tops of sides and partition walls are machine finished. The bases of both components are tested to confirm their fla
35、tness over their full area. The top covers, which carry the water inlet and outlet tubes are made from flat brass plate and are soldered to the base parts so that the sides and partition walls make water-tight joints with the cover. The dimensions of the calorimeter are 76 mm 76 mm 25 mm deep and of
36、 the guard ring are 230 mm 230 mm 25 mm deep. The two components are assembled so that a gap of 0.8 mm exists between their adjacent sidewalls. To ensure that the base surfaces of the calorimeter and guard ring are co-planar and that the calorimeter remains centred in the guard ring, the two are pla
37、ced on a levelling plate with thin card spacers maintaining the gap between them. Brass links are soldered between the two inlet tubes and similarly between the two outlet tubes so as to lock the calorimeter and guard ring together. In order to calculate the thermal conductivity it is necessary to k
38、now the area through which the calorimeter receives heat from the test panel; this is that area represented by the calorimeter plus half the gap between the calorimeter and guard ring. The area is calculated either: a) from direct measurements with vernier callipers to 0.05 mm; or b) during construc
39、tion of the calorimeter and guard ring assembly, by measuring the dimensions of the calorimeter and those of the aperture into which it fits and taking the average of the two areas thus obtained. NOTEIt is essential that provision is made for the calorimeter/guard ring assembly, all metal piping and
40、 the furnace frame and case to be electrically earthed in conformity with current Institute of Electrical Engineers (IEE) Regulations. 5.6 Water supply, to the calorimeter and guard ring from a brass manifold, 22 mm in diameter, via plastics feed tubes which are as short as possible. Similar plastic
41、s tubing is fitted to the outlets and incorporates valves for carrying the flow of water through the calorimeter and the guard ring. The outlet ends of the plastics tubes are terminated by jets made from glass tube. Water is fed to the inlet manifold from a constant head tank capable of supplying 10
42、0 L/h. NOTEThe temperature of the water should be maintained constant and 0.5 K to 2 K below the ambient temperature. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 BSI 08-19993 Figure 1 Vertical section through thermal con
43、ductivity apparatus Figure 2 Horizontal section, showing arrangement of heaters Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 4 BSI 08-1999 Table 1 Resistance wire for heaters MaterialHeaterWire diameter Resistance at room
44、 temperature Length of wire Space between turns in heater Platinum-20 % rhodium wire Main mm 0.5 7 9.3 m 9.1 mm two end elements: 5 two inside elements: 5 7.5 over middle 114 two centre elements: 7.5 Side0.59.79.43.8 to 4.0 Outer0.512.111.53.8 to 4.0 Lower peripheral0.513.212.83.3 to 3.5 High temper
45、ature electrical resistance wire Middle peripheral 1.69.212.812 to 13 turns per 25 mm of coil Top peripheral1.69.212.8 Supplementary heater 1.623.133even spacing (see note) NOTEThe spacing of the supplementary heater is not critical. NOTEThe circuit is repeated for each heater. The relay contacts RL
46、A are operated by the temperature controller. The variable resistors VR1 and VR2 allow adjustment of low and high current values. Values of R, VR1 and VR2 for an individual heater circuit will depend on the type of heater element and specification of the power regulator. Figure 3 Basic circuit for h
47、eater control system Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1902-5.5:1991 BSI 08-19995 5.7 Four mercury in glass thermometers, for measuring the inlet and outlet temperatures of the calorimeter and guard ring. The thermometers ha
48、ve a certificate of calibration, are capable of measuring temperature over the range 0 C to 25 C, graduated in 0.1 K and capable of being read to 0.01 K using an attached magnifier. NOTEMultiple thermocouples or platinum resistance thermometers may be used provided they are calibrated against a ther
49、mometer of certified accuracy and allow temperature difference between the calorimeter inlet and outlet water to be read to 0.02 K. 5.8 Ten thermocouples, of type R (platinum/platinum 13 % rhodium) in accordance with BS 4937-2, for measuring temperatures of the test panel (see clause 6) and which are connected to a temperature measuring instrument (5.9) using compensating connectors and cable. Figure 4 Design of calorimeter and guard ring Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:18:46 GMT+0