Steam is the key secondary energy, which is commonly used for heating, cooling, and heat in the production process as the heat carrying steam parameters. According to incomplete statistical analysis, the annual output of steam in China is 2 billion tons, so improving the production, transportation and application efficiency of steam can save a lot of electric energy. In China, it is not only a powerful energy consumption country, but also a country with low utilization rate of electric energy. In the capitalist period, steam, like other electric energy, is also a national "unified purchase and marketing". The price is not reasonable, which not only harms the initiative of operators to improve the quality of steam, but also harms the initiative of users to save energy. With the development trend of the market economy system in the socialist society, the steam is gradually moving to the market, from the state distribution, state price to supply on demand, quality and quantity charging standards. That will promote the company to improve the management ability of electric power energy, improve the quality of processing technology, reduce energy consumption, improve acquisition, avoid luxury waste, and make the basic national policy of resource conservation sufficient to implement.

However, the measurement and verification of steam (very wet steam) has always puzzled the flow calculator staff. Its shortcomings: to improve the project management level, it is necessary to have measurement verification.

(1) At present, there is no unified specification for magnetic flowmeter in China, and the uncertainty of instrument panel system software can not be evaluated, so that the differences caused by volume difference between trade can not be resolved.

(2) The selection of instrument panel model lacks the specific guidance of standardized technical basis, which makes the selection, installation and application of instrument panel model unscientific, resulting in excessive measurement error.

(3) Because of its own physical characteristics, saturated steam often occurs in the whole process of transportation in the form of two-phase flow of steam and water (i.e. the dryness of saturated steam is less than 100%). At this stage, the dryness is not adjusted in the steam flow measurement, which greatly reduces the measurement.

2.1 problems related to foreign trade trading enterprises (4) customers use the said thermal energy instead of high-precision flowmeter itself to apply steam, so it is not reasonable to use quality as steam clearing enterprise.

Heat energy is a state parameter. Steam with different conditions and equal quality has a large distance of heat energy. For example: under the standard of working pressure of 0.8MPa and temperature of 200C

Each kilogram of superheated steam contains 2838.6kj of heat energy, and each kilogram of superheated steam contains 2884.2mj of heat energy at a working pressure of 0.8ma and a temperature of 220c, with a distance of 1.6%. Therefore, the liquidation enterprise taking quality as steam can not really reflect the use value of steam. This will cause some hot customers not to take the initiative

Use steam to find new sources of heat.

Relative mathematical analysis model and uncertainty measurement, in addition, we fully consider the habit of using steam quality as work handover enterprise for many years, as a connection, and still keep quality: the national standard of steam flow measurement method (hereinafter referred to as "steam standard") for the above-mentioned situation, we will liquidate the enterprise with calorific value and thermal energy as steam, and draw the conclusion that

The quantity is the steam liquidation enterprise, and the relative mathematical analysis model and uncertainty measurement are obtained.

2.2 problems related to the adjustment of the dryness of wet steam saturated steam accounts for a very large proportion of the steam. Wet steam is the specific storage of saturated steam