Pressure gauge temperature error calculation used to use to help
China's national standard stipulates that the use of ambient temperature gauge deviation from 20 ± 2 ℃ (0.25 Precision Pressure Gauge), 20 ± 3 ℃ (0.4 Precision Pressure Gauge) or 20 ± 5 ℃ (normal pressure gauge), the pressure gauge The indication error, (including zero
)should not be greater than the limits prescribed by the following formula:
Δ = ±( δ + K Δt )
Formula: Δ ── Ambient temperature gauge deviation from 20 ± 2 ℃ (0.25 Precision Pressure Gauge), 20 ± 3 ℃ (0.4 Precision Pressure Gauge) or 20 ± 5 ℃ (normal pressure gauge) when the pressure indication error limit,%.
δ ── China's national standard value stipulated in the basic error of the pressure that the absolute limit,% .0.25 Precision Pressure Gauge 0.25% 0.4 0.4% precision pressure gauge, pressure gauge 1.6 General 1.6% 2.5 General Pressure Gauge 2.5%, 4.0 General pressure gauge was 4.0%.
── Deviate from the temperature values= | t2-t1 |,℃
. Formula t2
Chinese national standard gauge specified in the normal work environment within the temperature range of any value. Precision Pressure Gauge normal working temperature 5 ~ 40 ℃, the general gauge normal working temperature -40 ~ 70 ℃.Formula t1
China's national standard for the election specified in the value of,When t2
was higher than 22 ℃ (0.25 Precision Pressure Gauge) when 22 ℃,When t2
was higher than 23 ℃ (0.4 Precision Pressure Gauge) when 23 ℃,When t2
was higher than 25 ℃ (normal gauge) is 25 ℃,when t2
lower than 18 ℃ (0.25 Precision Pressure Gauge) when 18 ℃, When t2
lower than 17 ℃ (0.4 Precision Pressure Gauge) when 17 ℃, When t2
lower than 15 ℃ (normal pressure gauge) when to 15 ℃.
K ── Affected by ambient temperature gauge factor, 0.04% / ℃ (does not apply to constant elastic material, elastic material constant K value calculated in accordance with the provisions of the relevant material standard.)
Use of environmental temperature gauge error calculation example:
Maximum value of a pressure gauge measuring 1MPa precision grade 0.4, dial grooves 200 points grid, the actual use of environmental temperature is 26 ℃.
Value δ = 0.4% t2
= 23℃ t1
= 26℃ K = 0.04%/℃
── Deviate from the temperature values = | t2
|℃ = | 23℃ - 26℃ | = 3℃
Δ = ±( δ + K Δt
) = ±( 0.4% + 0.04%/℃ × 3℃ ) = ±( 0.4% + 0.12% ) = ±0.52%
Then, the pressure gauge at 26 ℃ ambient temperature to allow use of the basic error of ±( 1MPa × 0.52% ) = ±0.0052MPa
For the visual purposes, we use the gauge at 26 ℃ ambient temperature allowed under the fundamental error ±0.0052MPa Converted into the equivalent of the size of the smallest sub-grid:
The pressure gauge the value of the minimum sub-grid scale value = pressure gauge dial gauge groove ÷ total number of grid points = 1MPa ÷ 200 = 0.005MPa / sub-grid
The pressure gauge at 26 ℃ ambient temperature to allow use of the basic error of ± 0.0052MPa equivalent to the size of the smallest sub-grid = ± (ambient temperature gauge allows the use of basic error ÷ gauge the value of the smallest sub-grid) = ± ( 0.0052MPa ÷ 0.005MPa / sub-grid) = ± 1.04 sub-grid. not only to use the pressure gauge at 26 ℃ ambient temperature allowed under the basic error of indication ± 1.04 个 smallest compartments.
The sample temperature using the pressure gauge error calculation tools, operation sequence is:
- ① The upper limit of the pressure gauge measuring the drop-down list box, select 1MPa
- ② Accuracy class in the pressure gauge drop-down list box, select 0.4
- ③ Grid points in the pressure gauge dial the number of drop-down list box, select the 200 sub-grid
- ④ In the text box using the ambient temperature of 26
- ⑤ Reference temperature gauge conditions in the drop-down list box, select the 23 ℃. Later, the basic error in the indication limit the text box will show the temperature gauge in the reference work permit under the basic error of the results ± 0.004 MPa, in minimum value of sub-grid dial text box will show the minimum in the pressure gauge the value of sub-grid calculations 0.005 MPa, the fundamental error in allowing the equivalent of the text box will show a pressure gauge to deviate from the reference temperature conditions of the permit basic error is equivalent to gauge the size of the smallest sub-grid ± 1.04 个 smallest sub-cell, the fundamental error in allowing the text box showing the value of a gauge will appear to deviate from the reference temperature conditions, the basic error allowed, ± 0.0052 MPa .