This regulation is applicable to the initial verification, subsequent verification and in-service inspection of liquid level gauges (excluding radiation level gauges). The calibration of level gauge can refer to this regulation.
2 Normative references
The following document is referenced in this regulation:
JJG 882 Pressure Transmitters
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
3 Terms and meteorological units
3.1 Terms
3.1.1 level
generic term of liquid level, material level and interface (position) is a parameter reflecting the total amount of objects and the surface characteristics of materials
3.1.2 liquid level gauge
Instruments used to indicate and control liquid level and interface (position) in industrial process measurement and control system
3.2 Measurement unit
The legal measurement unit used by level gauge is m (meter), or its decimal multiple unit: mm, cm, etc.
4 General
Liquid level gauges are widely used to measure the internal liquid level or interface of tanks, kettles, towers, bottles, furnaces and canals in industrial processes.
The liquid level measurement methods include visual method, manual measuring method, blowing method, force measuring method, pressure method, electrical characteristic method, reflection method, thermal method, radiation method, neutron method, etc.
Liquid level gauges can be divided into contact type and non-contact type according to the measurement mode, can be divided into top-mounted, side-mounted, top-bottom, side-side, side-bottom, top-side and side-wall types according to installation modes, and can be divided into communication type, buoyancy type, pressure type, reflection type and electrical characteristic type according to the measuring principle.
