Pressure gauge
close Interpreting the quality standards and indicators of pressure instruments Pressure instruments attach great importance to their quality standards and have restrictions on indicators. 1. Standards followed by pressure instruments The instruments produced by the pressure instrument industry should be produced in accordance with the standards to ensure the quality of the manufactured products. There are three standards for pressure instruments: national standards, ministerial standards and professional standards. (1) The current national standards include general pressure gauge standard, precision pressure gauge standard and piston pressure gauge standard. (2) Ministerial standards include ammonia pressure gauge standard, electric contact pressure gauge standard, capsule pressure gauge standard, electric contact capsule pressure gauge standard, error gauge standard, gear transmission mechanism standard, and matching gauge standard of pressure detector. (3) There should be professional standards for the production of instruments without national standards and ministerial standards. In addition, in order to improve the manufacturing quality of products, the pressure instrument industry has also formulated the quality grading of superior products, first-class products and qualified products. Such as piston pressure gauge, precision pressure gauge, general pressure gauge, electric contact pressure gauge and ammonia pressure gauge. 2. Commonly used quality indicators of pressure instruments The commonly used quality indicators of pressure instruments are specified under the conditions of participating in the work: 1) The instrument is in the normal working position (means vertically placed); 2) Uniform load change; 3) Ambient temperature (pressure instruments of different accuracy levels have different temperature regulations, such as the ambient temperature of 0.4 precision pressure instruments is 20 ℃ ± 31C). Common quality indicators are as follows. (1) Basic error of indication The basic error of indication of an instrument is expressed by reference error, which refers to the percentage between the maximum absolute error of the instrument and the maximum measurement range of the instrument under normal use conditions. According to the different specifications and accuracy levels of various instruments, the basic error limits of indication of various instruments are specified. Instruments whose basic error of indication is less than the basic error limit of indication are qualified instruments. (2) The return difference (variation) is at the same pressure value, and the difference between the rising and falling pressure values of the instrument shall not be greater than the absolute value of the basic error limit of the indication. (3) Accuracy level The accuracy level of the instrument is expressed by the absolute value of the maximum basic error of indication and the percentage of the measurement range ratio under standard conditions. According to the use of various pressure instruments, all instruments are classified into different grades according to their indication accuracy. In general, the pressure instrument has requirements for its quality, so we should strive to meet that requirement. There are also some regulations on its quality indicators, which are described in detail above.