The selection of pressure gauge pressure gauge accuracy level

by:DEFUS     2020-06-22
Pressure gauge is a lot of more phyletic, it not only has the general ( Ordinary) Pointer type indicator, and digital type; Not only has a regular pattern, and special type; Not only have a contact, and remote transmission; Not only has resistance to vibration mode, and resistant; Not only have the diaphragm, and corrosion resistance, etc. Pressure gauge of the basic introduction? Pressure gauge series complete. It not only has a regular series, as well as digital series; Not only has ordinary medium application series, and application of special medium series; Not only switch signal series, but also far eastone signal series and so on, they all originated from practical requirements, has formed the complete series. Pressure gauge specifications complete, perfect structure. From the nominal diameter, there are 40 mm, 50 mm Φ, Φ Φ 60 mm, 75 mm, 100 mm Φ Φ, Φ 150 mm, 200 mm, 250 mm Φ Φ, etc. Look from the installation structure, there is a direct installation type, built-in type and convex mounted, the embedded type is divided into radial embedded type and axial built-in type, convex mounted also has a convex mounted radial and axial convex mounted. Mounted directly, is divided into radial installed directly and axial installed directly. The radial installed directly type is a basic type, generally in unspecified installation structure, shall mean the radial mounted directly. Axial directly mounted to consider their own support stability, generally only in nominal diameter less than 150 mm on the pressure gauge to choose. The so-called embedded type and convex type pressure gauge, is we often say with edge ( Install the ring) Pressure gauge. Axial built-in type shaft with forward edge, both radial embedded type refers to the front of the radial edge, radial convex mounted ( Also called wall type) After refers to the radial edge pressure gauge. From the domain and range blocks in the amount of positive pressure field can be divided into micro pressure range section, low voltage range section, medium voltage range section, ultra-high pressure section section, high pressure, each range segment and segment out several kinds of measurement range ( Instrument range) ; In the amount of negative pressure domain ( Vacuum) There are three kinds of negative pressure ( Vacuum table) ; Positive pressure and negative pressure connecting the pressure gauge is a kind of cross domain pressure gauge. Its specification name for pressure vacuum gauge, there are also called vacuum pressure gauge. It not only can measure positive pressure stress, also can measure the suction pressure. Pressure gauge the accuracy of classification is very clear. There are 4, 2 common precision level. Level 5, 1. 6, 1, 0. Level 4, 0. 25, 0. 16, 0. Level 1 and so on. Precision grade generally should be identified on the dial, its identity also have corresponding provisions, such as '1' said its precision grade is grade 1. Level is very low for some precision pressure gauge, such as grade 4, and some do not need to measure the accurate pressure value, just need to indicate the pressure range, such as fire extinguisher on the pressure gauge, you can not identify precision grade. The selection of pressure gauge precision grade? 【 Answer 】 According to the process to allow maximum absolute error and the selected instrument most cheng, calculate the instrument allows the maximum error of the reference, in the regulations of the state, the accuracy grade of determine the accuracy of the instrument. In general, chooses the precision instrument, measurement results are more accurate and reliable. But cannot think of chosen instrument accuracy is higher, the better, because the precision of the instrument in general, the more expensive, operation and maintenance, the more trouble. On the premise of meet the technological requirements, therefore, should as far as possible choose low accuracy, quality and durable instrument. Choose, for example: 1, used for measuring the viscous or the special medium such as acid and alkali, should choose the diaphragm pressure gauge, stainless steel spring tube, stainless steel, stainless steel shell or bakelite shell. According to the measured medium is different, on the pressure gauge shall be stipulated by the color scale, and indicate the name of the special medium, oxygen gauge must be marked in red word 'oil' ban, hydrogen with dark green under horizontal color code, color scale ammonia under the yellow line, and so on. 2, when installation, against the wall should be chosen on the edge of the pressure gauge; Directly installed on the pipeline, should choose without the edge of the pressure gauge; When used for direct measurement of gas, should choose watchcase behind a security hole pressure gauge. For reasons of pressure management position and convenient for observation, should choose the size of the casing diameter.
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