【正文】 (HP) for connection with lens seal Figure 3 NOTE. Minimum height h of flats shall be patible with use of standard spanners according to ISO 10102. Figure 2 1) According to ISO 1302. Page 6 EN 8371 : 1996 BSI 1998 Table 7. Dimensions of parallel threaded tapped holes Dimensions in millimetres Thread size d1 d2 t1 20,5 t2 min. G 1/8 4,5 10 7,5 G 1/4 5,5 13 10 G 3/8 6,5 16 12 G 1/2 7 19 15 Table 6. Dimensions of taper threaded shanks Dimensions in millimetres Thread size d1 l1 min. w min. 1/827 NPT EXT 10 8 1/418 NPT EXT 13 10 1/214 NPT EXT 18 17 NOTE. Height of flats (h) shall be patible with use of standard spanners according to ISO 10102. Table 8. Dimensions of sealing washers Dimensions in millimetres Thread size d2 d3 e 0,2 G 1/8 B +0,2 8 0 1,5 G 1/4 B +0,2 9,5 0 1,5 G 3/8 B +0,3 13 0 2 G 1/2 B +0,4 17,5 0 2 Shanks with taper pipe threads Figure 4 Sealing washers For use with parallel screw threads only. NOTE. The choice of the sealing washer material depends on the pressure and the fluid to be measured. Figure 6 Parallel threaded tapped holes 4,2 0 5,2 0 5,7 0 6,2 0 20,2 20,2 20,3 20,5 Sealing lens For use with high pressure shank (HP) only, according to . Figure 5 Figure 7 1) According to ISO 1302. Page 7 EN 8371 : 1996 BSI 1998 Type of mounting and connection position The different mounting types of gauges shall be as given in table 9. When mounting, ensure that there is enough free space for the blowout device, if any. Table 9. Type of mounting and connection position Radial connection 10 11 12 Type not preferred Centre back connection 20 21 Type not preferred 22 23 Offset back connection 30 31 Type not preferred 32 33 Direct mounting Surface mounting Flush mounting Threehole fixing Clamp fixing Page 8 EN 8371 : 1996 BSI 1998 Table 11. Maximum permissible errors Accuracy classes Limits of permissible error (percentage of span) 0,1 0,1 % 0,25 0,25 % 0,6 0,6 % 1 1 % 1,6 1,6 % 2,5 2,5 % 4 4 % 8 Pressure element assembly 9 Requirements The test methods for these requirements are given in clause 10. Accuracy The total errors of indication at reference temperature 20 8C of the gauge shall not exceed the values given in table 11. Installation of the pressure gauges shall not cause any change of readings. Table 11 shows the limits of permissible error as a percentage of span at reference temperature 20 8C corresponding to accuracy classes. Page 9 EN 8371 : 1996 BSI 1998 Hysteresis Hysteresis error in pressure gauges shall not exceed the absolute value of the limits of permissible error at reference temperature 20 8C. EXAMPLE Pressure gauge with a maximum scale value of 10 bar, accuracy class 1. The maximum permissible hysteresis error is 1 %. The difference between the readings taken at decreasing and increasing pressure shall not exceed 0,1 bar (= 1 % of 10 bar). Temperature effect The variation of indication caused by effects of temperature shall not exceed the percentage values given by the formula: 0,04 3 (t2 2 t1) % of the span where: t1 is the reference temperature in degrees Celsius。 1,6。 0,6。 Test Ea and guidance: Shock Combined pressure and vacuum ranges in bar: 21 to +0,6 21 to +3 21 to +9 21 to +24 21 to +1,5 21 to +5 21 to +15 The SI units kilopascal (kPa) and megapascal (MPa) should follow the bar series from 0 to 60 kPa up to 1000 kPa, then change to 0 MPa to 1,6 MPa up to a maximum of 160 MPa. Page 4 EN 8371 : 1996 BSI 1998 Table 2. Dimensions Dimensions in millimetres Nominal size d1 d2 d3 d4 40 38 61 51 3,6 50 48 71 60 3,6 63 61 86 75 3,6 80 78 110 95 5 100 97 134 118 6 150 147 186 168 6 160 157 196 178 6 250 245 290 276 7 NOTE. d4 elongated holes can be accepted to ensure interchangeability with previous standards. Table 1. Nominal size pared to the accuracy class Nominal size Accuracy class 0,1 0,25 0,6 1 1,6 2,5 4 40 and 50 X X X 63 X X X X 80 X X X X 100 X X X X 150 and 160 X X X X 250 X X X X X Table 3. Thread forms and sizes Parallel pipe threads Taper pipe threads G 1/8 B G 1/4 B G 3/8 B G 1/2 B 1/827 NPT EXT 1/418 NPT EXT 1/214 NPT EXT NOTE. G 3/8 B is not preferred. 6 Accuracy classes The accuracy class stating the limits of permissible error is expressed as a percentage of the span. The following accuracy classes are defined: 0,1。 Basic environmental testing procedures 208。 Part 2: Tests 208。 Pressure gauges used for welding, cutting and allied processes EN 29539 : 1992 Materials used for equipment used in gas welding, cutting and allied processes (ISO 9539 : 1988) EN 60529 : 1991 Degrees of protection provided by enclosures Vacuum ranges in bar: Vacuum gauges have anticlockwise pointer travel with increasing vacuum. 20,6 to 0 21 to 0 EN 6006826 : 1995 EN 60068227 : 1993 Electrical engineering 208。 wrenches specified in EN 562. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are ci