Wellhead pressure gauge Wellhead Pressure Gauge
The accuracy level of the pressure gauge adopts R5 digital series. In the past, 1.5 at the level of pressure gauge did not belong to the number of R5 numbers, so it was necessary to abolish, and the closest 1.6 is replaced by 1.5. Therefore, it is no longer allowed to set the pressure gauge to level 1.5.
Why is the accuracy level of the pressure gauge 1.6?
Gas Manometer Gas Manometer
Why should the accuracy level of the general pressure gauge use level 1.6 instead of level 1.5?
To understand the basic knowledge of the priority system in standardized technology. For the digital system, the national standard GB/T321 stipulates the “priority digital system”, and uses a 1/n power of 1/n with a public ratio of 10, respectively 1/5, 1/10, 1/20, 1/40, 1 /80, the code is R5, R10, R20, R40, R80. The accuracy level of the pressure gauge is the R5 digital series.
The R5 number system is: 1/5 of the 10th side = 1.60. The number of numbers includes: 1.0, 1.6, 2.5, 4.0, 6.3, 10.
In the past, 1.5 at the level of pressure gauge did not belong to the number of R5 numbers, so it was necessary to abolish, and the closest 1.6 is replaced by 1.5. Therefore, it is no longer allowed to set the pressure gauge to level 1.5.
The ratio of two adjacent numbers is equal to R5.例如:10/6.3=1.6,6.3/4=1.6,4/2.5=1.6,2.5/1.6=1.6,1.6/1＝1.6,还可以继续往下:1/0.63=1.6,0.63/0.4＝1.6, 0.4/0.25 = 1.6, 0.25/0.16 = 1.6, 0.25/0.16 = 1.6, …
Of course, if you have a composition, you can also derive the level on both sides of a certain accuracy level after rounding. For example, level 2.5, one higher than it is 2.5 ÷ 1.6 = 1.6 level, and one level lower than it is 2.5 × 1.6 = 4. Detailed knowledge about the digital system can read national standards.
At the same time, it is also described in the general pressure sheet accuracy level in the general pressure sheet accuracy level in the general pressure sheet accuracy of the GB/T1226-2010 GB/T 1226-2010:
If you do not see such expressions in the corresponding books, everything is based on the latest national standard!
The difference in pressure gauge accuracy level 1.6 and 1.5?
The pressure gauge is installed on The Pressure Gauge Is Mounted on the
The accuracy level of the pressure gauge refers to the percentage of the pressure gauge allowed error to accounted for a full range.
For example, a pressure table is 100MPa and the accuracy level is 1.6, then its allowable error is 100MPa × 1.6%= ± 1.6MPa. If the accuracy level is 1.5, its allowable error is 100MPa × 1.5%= ± 1.5MPa.
Under normal use conditions, the accuracy of the measuring result is called the accuracy of the instrument. The smaller the reference error, the higher the accuracy of the instrument, and the reference error is related to the range range of the meter. Therefore, when using the same accurate instrument, the scope of compression is often adopted to reduce the measurement error. In industrial measurement, in order to facilitate the quality of the instrument, the accuracy level is usually used to represent the accuracy of the instrument. The accuracy level is the maximum reference error remove the positive, negative sign and percentage number. The accuracy level is one of the important indicators to measure the quality of the instrument.
In industrial measurement, in order to facilitate the quality of the instrument, the accuracy level is usually used to represent the accuracy of the instrument. The accuracy level is the maximum reference error to remove the positive, negative sign and percentage number. The accuracy level is one of the important indicators to measure the quality of the instrument.
Instrument accuracy = (maximum value/meter range of absolute error)*100%
The above calculation formula is absolutely valuable to remove%is the accuracy level we see.
So how to define the current 1.5 level pressure gauge?
According to the current national standards of the pressure gauge, the accuracy level is 1.6, and the allowable error error of level 1.5 pressure gauge in use is calculated at level 1.6, and the accuracy level can not be changed.
Common pressure gauge accuracy level
The precision pressure gauge accuracy is 0.1, 0.25, and 0.4;
The accuracy of the normal pressure gauge 1.0, level 1.6 (formerly 1.5), level 2.5, level 4.0 (basically no); basically no);
The pressure gauge on the surface above 60 is basically level 1.0, 1.6 level;
60 and below surface pressure gauges are basically level 2.5;
Film box and membrane pressure gauge are generally level 2.5;
The difference between the accuracy and the degree of pressure gauge
Heating system. Close the pipe with pressure gauge Heating System. Close up of pipes
The minimum score of the pressure gauge can be regarded as its resolution, but it is not necessarily the accuracy of the table.
Because the pressure gauge is a detector, there is a certain error displayed to us. There is a certain error between the measurement value and the real value. The range of this error is actually accuracy. The closer to the real value, the higher the credibility.
Pressure gauge accuracy level inspection
The accuracy level of the pressure gauge is the abbreviation of the accuracy level or accuracy level of the pressure gauge. “Pressure vacuum table and vacuum table” call the accuracy level of the instrument.
Under the conditions of reference, the inspection of the accuracy level of the pressure gauge shall include the following four items:
1. Display value error
Within the measurement range, the value error shall be not greater than the allowable errors specified in Table II.
2. Return error
Within the measurement range, the return error should not be greater than the absolute value of the allowable error specified in Table II.
3. Tap a light shift
After the case is tapped, the value of the pointer’s display value should not be more than 1/2 of the absolute value of the permissible error specified in Table II.
4. Poems of pointer deflection smoothness
Within the measurement range, the pointer deflection should be stable, without beating and stuck.
Pressure table accuracy level meaning
The accuracy level of the pressure gauge is represented by the percentage of allowable errors to occupy the stress meter range. It is generally divided into 0.5, 1, 1.6, 2, 2.5, 3, and 4 seven levels (level 3 and level 4 on the boiler). The smaller the value, the higher the accuracy. For example, the volume range of 0 ～ 2.5MPa accuracy of 2.5 -level pressure gauge, the allowable error between the pressure value shown in the pointer and the actual pressure value of the measured medium shall not exceed 2.5MPa × 2.5 % = ± 0.0625MPa; When the pressure indicates the pressure of 0.8MPa, the actual air pressure is between 0.7375 and 0.8625MPa.
It can be seen that the actual error of the pressure gauge is not only related to accuracy, but also related to the scale of the pressure gauge. When the range is the same, the higher the accuracy (the smaller the number), the smaller the permission error of the pressure gauge. When the accuracy is the same, the larger the range, the greater the error of the pressure gauge.
Pressure table selection
Pressure gauge is a common metering ulood, which is widely used in various production areas. The selection of the pressure gauge shall, under the premise of meeting the technical requirements of the use, should be comprehensively considered in accordance with the principles of saving and practical, so that the accuracy level, range, type, and model should be reasonably selected.
1. Determination of pressure gauge accuracy level
The accuracy levels of the precision pressure gauge are 0.1, 0.16, 0.25, and 0.4, respectively; the accuracy levels of the general pressure gauge are 1.0, 1.6, 2.5, and 4.0. The method of selecting the accuracy of the pressure gauge: according to the requirements of the production process, economic practical, and testing methods, the accuracy level should be determined according to the allowable error required by the measured pressure to be minimum.
2. The choice of pressure gauge range
(1) When measured stable pressure, the maximum work pressure should not exceed 2/3 of the range.
(2) When measuring pulse pressure, the maximum work pressure should not exceed 1/2 of the range
(3) When measuring high pressure, the maximum work pressure should not exceed 3/5 of the range
(4) In order to ensure the accuracy of measurement, the minimum work pressure should not be less than 1/3 of the range.
According to the above principles, after calculating a value according to the maximum pressure measured, the value of the selected range is selected from the stroke range series, which is the selected range.
3. Selection of the type of pressure gauge
Different types of pressure gauges should be used to measure different media and use environment
(1) General medium, such as air, water, steam, oil, etc., can be used as a normal pressure gauge.
(2) For special media, special pressure gauges, such as ammonia for ammonia for ammonia; oxygen oxygen pressure gauges; hydrogen pressure gauges; ethyl acetylene pressure gauges, and so on.
(3) For general corrosive media and corrosive gas environments, stainless steel pressure gauges can be selected.
(4) For the measuring viscosity, liquid, gas, or solid floating material measurement of liquid, high temperature, high temperature, high temperature, and high temperature, choose diaphragm pressure gauges.
(5) Pressure measurement for pulse media and mechanical vibration occasions. Use a shock -resistant pressure gauge.
(6) You can choose a far -pass pressure gauge when there is a long pass, and the remote signal has a current and resistance type and voltage type.
(7) Electric connection point pressure gauges can be selected when there are control protection requirements.
(8) Explosion -proof types must be selected when there is explosion -proof requirements, such as explosion -proof power access pressure gauges.
The accuracy level of the pressure gauge is divided by the percentage of its allowable error to occupy the dial section value. The larger the accuracy level, the greater the allowable error to occupy the dial scales. The greater the stroke range of the pressure gauge, the more accurate levels, the greater the absolute value of the pressure value of the pressure value.
Use in industry: The accuracy of the often used pressure gauge is 2.5 and 1.6. If it is 1.0 and 0.5 levels belongs to a high -precision pressure gauge, some digital pressure gauges have reached level 0.25 now. The accuracy level of the pressure gauge is divided by the percentage of its allowable error to occupy the dial section value. The larger the accuracy level, the greater the allowable error to occupy the dial scales. The greater the stroke range of the pressure gauge, the more accurate levels, the greater the absolute value of the pressure value of the pressure value.