1、 What is precision level?
Accuracy level is an indicator that measures the maximum allowable error between the measured value and the true value of a pressure gauge. It is usually represented by a number, the smaller the number, the higher the accuracy, the smaller the allowable error range, and the higher the manufacturing cost.
2、 The representation method and meaning of accuracy level
The accuracy level is usually expressed as a percentage, and its error calculation is based on the range of the pressure gauge (full-scale value, F.S.), rather than the current reading value.
Calculation formula: Maximum allowable error=± (accuracy level% x pressure gauge range)
For example:
A pressure gauge with a range of 0-1.0 MPa and an accuracy level of 1.6.
The maximum allowable error is ± (1.6% × 1.0 MPa)=± 0.016 MPa.
This means that regardless of where the pointer points within the range (such as 0.2 MPa or 0.8 MPa), the allowable error is within ± 0.016 MPa
0.1, 0.25/precision type/± 0.001 MPa, ± 0.0025 MPa/laboratory, precision instrument calibration, scientific research and development, standard table
0.4, 0.6/precision type/± 0.004 MPa, ± 0.006 MPa/high-precision process control, testing bench, engine fuel system testing.
1.0/High precision industrial type/± 0.01 MPa/Industrial processes that require high pressure control, such as critical pneumatic/hydraulic control.
1.6/General industrial type/± 0.016 MPa/Most commonly used and economical. General industrial equipment, air compressors, water pumps, HVAC systems, etc
2.5/Ordinary type/± 0.025 MPa/Equipment with low precision requirements, such as agricultural machinery and low precision monitoring.
4.0/Low precision type/± 0.04 MPa/Non critical, rough indication occasions.
Summary: In the field of industrial processes, level 1.6 is the absolute mainstream choice; When higher precision is required, 1.0 or 0.6 level will be chosen; And 0.25 level and above are usually used as “standard tables” for verifying ordinary tables.
According to the material and structure of the watch case:
Standard stainless steel (such as SUS304, SUS316): universal corrosion resistance.
Shock resistant (liquid filled) type: The shell is filled with glycerin or silicone oil, used in situations with strong pulses or vibrations, which can lubricate parts, reduce vibration, and prevent pointer shaking.
Oil free (oxygen only) type: All components that come into contact with gas must strictly prohibit oil to prevent explosion caused by reaction with oxygen.
Diaphragm (chemical seal) type: It isolates corrosive, high viscosity, or easily solidified media through a diaphragm to protect the interior of the instrument.
According to international standards, in addition to Chinese standards (GB/T), there are also European standards such as EN 837 and American standards such as ASME B40.1, whose accuracy level definitions are basically the same.
summary
When choosing a stainless steel pressure gauge, first determine the accuracy level according to the process requirements (usually 1.6 level is the starting point), then choose whether special structures such as shock resistance and diaphragm are needed based on the characteristics of the medium, and finally ensure the correct range selection. Understanding the meaning of precision level is the key to making correct and economical choices.