CN101476962A - Pressure meter effective area measuring method - Google Patents

Abstract

The invention relates to a pressure gauge effective area measuring method. The method is suitable for piston type pressure gauge effective area measurement, and also suitable for floating ball type pressure gauge effective area measurement. The method measures a detected pressure gauge through a standard pressure gauge, and comprises a measuring step and a calculating step, wherein the measuring step comprises a step of measuring the differential pressure between the standard pressure gauge and the detected pressure gauge. The pressure gauge effective area measuring method and a device have the advantages of novel structure, convenient use and no need of manpower observation on balance state, can be widely applied to effective area measuring tests of a piston type pressure gauge and a floating ball type pressure gauge, and has high realistic meanings.

Description

Pressure meter effective area measuring method

Technical field

The present invention relates to a kind of pressure meter effective area measuring method, be applicable to the piston gage effective area measuring, also be applicable to the float-ball type pressure meter effective area measuring.

Background technology

Piston gage is a kind of standard metrology appliance of gaging pressure, and piston effective area is the main technical indicator of piston gage.

The mensuration of piston gage piston effective area is to carry out according to the method for national metrological verification regulations regulation at present.These rules are respectively:

JJG 59-2007 " piston manometer vertification regulation ";

JJG 236-1994 " first-class standard piston-type pressure vacuum gauge ";

JJG 51-2003 " band equilibrium liquid column piston formula pressure vacuum gage vertification regulation ";

JJG 239-1994 " two, third-class standard piston-type pressure vacuum gauge ";

JJG 942-1998 " float-ball type pressure gauge ".

The method of existing measurement verification regulations regulation is:

The standard piston 1 of known area and the tested piston 2 of area to be determined are installed on the same pressure validator, on two pistons, apply counterweight m respectively ₁And m ₂Piston is risen to working position and in running order, by adjusting m ₁And m ₂Make two-piston be in the working position.Because two-piston is installed on the same checker, under the equilibrium state, this moment, the pressure of two piston lower surfaces equated:

$\frac{m_{1}g}{A_1}=\frac{m_{2}g}{A_2}$

So have: $A_2=\frac{m_2}{m_1}{A}_1$

In the formula: A ₁---the useful area of standard piston;

A ₂---the useful area of tested piston.

m ₁And m ₂---put on the specific weight quality of piston, contain piston and union piece quality thereof.

This method is called balancing method.

Stipulating in " duty " existing rules, is prior art, generally is meant: (1) for piston gage, piston arrives assigned address and according to the regulation rotational speed in the rules; (2) for the float-ball type pressure gauge, under the flow of regulation, ball float is in free suspended state.

Said method confirms by the rising and the downtrending of manual observation two-piston whether piston reaches equilibrium state, so be easy to generate following problem:

1) people's formula is observed and is judged equilibrium state, can't carry out automatic data collection.

2) when lower pressure (especially to gas piston and ball float), piston rises and descends all slower, and time-consuming length and equilibrium state are difficult for judging.

3) when one of piston decline rate is big, equilibrium state is difficult for judging.

When 4) measuring inferior grade float-ball type pressure meter effective area, can't realize balance with high-grade float-ball type pressure gauge.

Summary of the invention

Purpose of the present invention is exactly at above-mentioned deficiency, provide a kind of structure simple relatively, be easy to realize, piston gage effective area measuring method and device that measuring accuracy is high.

Pressure meter effective area measuring method provided by the invention, by the fixed tested pressure gauge of normal pressure instrumentation, comprise measuring process and calculation procedure, the step that has comprised the differential pressure between measurement standard pressure gauge and the tested pressure gauge in the measuring process realizes by differential pressure measuring installation is set between normal pressure meter and tested pressure gauge.Differential pressure measuring installation is generally differential pressure transmitter or differential pressure pick-up.

Owing to increased differential pressure measuring installation, like this, pressure meter effective area measuring method is:

Described measuring process is:

(1) respectively normal pressure meter and tested pressure gauge are connected to differential pressure measuring installation and pressure source; Ball float is connected with source of the gas, and source of the gas is necessary in the float-ball type pressure gauge, and source of the gas is air pump or gas cylinder.

(2) placing quality on the normal pressure meter is m ₁Counterweight, placing quality on the tested pressure gauge is m ₂Counterweight, these two counterweights are added on two pistons, estimate to produce identical nominal pressure;

(3) under the duty, it is Δ P that differential pressure measuring installation records differential pressure;

Described calculation procedure is:

Under the duty: $\frac{m_{1}g}{A_1}=\frac{m_{2}g}{A_2}+\mathrm{\ΔP}---\left(1\right)$

So: $A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\Δ}{\mathrm{PA}}_1}{A}_1---\left(2\right)$

In the formula: g---acceleration of gravity;

Δ P---the differential pressure between two pressure gauges;

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area.

m ₁And m ₂---put on two manometric specific weight quality, contain piston or ball float and union piece quality thereof.

Be the influence to measurement result of the static pressure error of eliminating differential pressure measuring installation, take following step that the static pressure error of each measurement point is revised: at each gaging pressure point, the differential pressure measuring installation two ends are communicated with, measuring its static pressure error is Δ P _a, and then the differential pressure measuring installation two ends are cut off, measurement standard pressure gauge and tested manometric differential pressure are Δ P _b, Δ P=Δ P then _b-Δ P _a, bring Δ P into formula (2), draw accurate more tested manometric useful area A ₂

For eliminating the influence of the lower surface difference in height between two pressure gauges, can take following method:

(1) adds the modified value method:, should add modified value ρ hg to Δ P according to gas column (or fluid column) difference in height when standard and tested piston lower surface during not at same surface level.

(2) starting point method: stipulate that at first a spot pressure is a starting point, places counterweight m on the normal pressure meter ₁₀, on tested pressure gauge, place counterweight m ₂₀, recording this differential pressure is Δ P ₀At measurement point the normal pressure meter is placed counterweight m ₁₁, tested pressure gauge places counterweight m ₂₁, recording this differential pressure is Δ P ₁Δ P=P then ₁-Δ P ₀, m ₁=m ₁₁-m ₁₀, m ₂=m ₂₁-m ₂₀, bring formula (2) into and draw accurate more tested manometric useful area A ₂

For preventing in the measuring process that differential pressure measuring installation bears unidirectional static pressure, some valves can be set, these valves can be used manual needle-valve, also can use solenoid valve.The first valve K1 is arranged between normal pressure meter and pressure source, the second valve K2 is arranged between tested pressure gauge and pressure source, the 3rd valve K3 is arranged between normal pressure meter and differential pressure measuring installation, the 4th valve K4 is arranged between tested pressure gauge and differential pressure measuring installation, between normal pressure meter and tested pressure gauge, with differential pressure measuring installation be parallel with the 5th valve K5.But different selection modes is arranged in actual applications, and not needing has all, particularly respectively may be different at piston gage and float-ball type pressure gauge array mode, and this is conspicuous.

It is also conceivable that the influence of aerostatic buoyancy in the reality, in relevant vertification regulation regulation is arranged, is prior art.

In order to improve the uncertainty of measurement result, differential pressure measuring installation can adopt the device of one group of different range, to improve measuring accuracy.

Also need in actual applications differential pressure measuring installation is selected, be generally differential pressure transmitter or differential pressure pick-up.Following requirement is arranged:

1), measurement range:

Measuring the upper limit should be greater than, two-piston maximum possible differential pressure value, and this value can be obtained the permissible variation value of nominal according to useful area in the correlation technique standard.

2), anti-static pressure:

Should be not less than the tested manometric measurement upper limit.

3), class of accuracy:

The uncertainty component that the measuring error of differential pressure measuring installation causes and the ratio of tested piston effective area permissible error should be enough little.

Pressure meter effective area measuring method provided by the invention, novel structure, easy to use does not need the manual observation equilibrium state, has solved following problem:

1, the data of differential pressure measuring installation can be passed through computer interface, handle automatically, are the gordian techniquies that realizes that useful area is measured automatically.

2, in particular cases be difficult to judge the problem of equilibrium state, make measurement result more objective.

3, make standard test float-ball type pressure meter effective area problem with the float-ball type pressure gauge.

This shows that the present invention can be widely used in piston gage and the float-ball type pressure gauge having very high realistic meaning in the effective area measuring test.

Description of drawings

Fig. 1 is the structure principle chart of the embodiment of the invention 1 and embodiment 2;

Fig. 2 is the structure principle chart of the embodiment of the invention 3 and embodiment 4;

Fig. 3 is the structure principle chart of the embodiment of the invention 5;

Fig. 4 is the structure principle chart of the embodiment of the invention 6;

Fig. 5 is the structure principle chart of the embodiment of the invention 7.

Wherein, 1. standard piston, 2. tested piston, 3. differential pressure measuring installation, 4. pressure source, 5. tested ball pneumatic dead wieght tester, 6. standard ball pneumatic dead wieght tester, 7. source of the gas, K1～K5 is a valve.

Embodiment

Embodiment with indefiniteness further explains, illustrates the technical program below.Embodiment 1 (the basic application)

A kind of pressure meter effective area measuring device, as shown in Figure 1, be applied to the effective area measuring of piston gage, comprise standard piston 1, tested piston 2, pressure source 4, differential pressure measuring installation 3, differential pressure measuring installation 3 is selected differential pressure transmitter 3 for use, wherein, standard piston 1 joins with differential pressure transmitter 3 positive pressure sides, and is connected with pressure source 4 by the first valve K1; Tested piston 2 joins with differential pressure transmitter 3 negative pressure ends, and is connected with pressure source 4 by the second valve K2.

1) at first selecting differential pressure transmitter, is example with 0.05 grade of (second-class) piston gage useful area measuring 0.25MPa.

Measurement range: according to the piston gage national standard, it is ± 0.4% that useful area of 0.05 grade of (second-class) piston and nominal value allow maximum difference.That is, the maximal value of Δ P is:

ΔP _max±0.4％×0.25MPa＝±1kPa

So the measurement range of the differential pressure transmitter of selecting should be less than 0～± 1kPa.

Anti-static pressure: should be not less than piston gage and measure upper limit 0.25MPa.

Class of accuracy: 0.05 grade of (second-class) piston effective area uncertainty is 0.1%, requirement is ignored by the uncertainty that the differential pressure transmitter measuring error causes, then the measuring error of differential pressure transmitter should cause 1/5 of uncertainty less than 0.05 grade of (second-class) piston effective area error.

To 0.25MPa0.05 level (second-class) piston, minimum measuring point is 0.05MPa, and maximum measuring point is 0.25MPa.Corresponding to minimum measuring point, require the permissible error of differential pressure transmitter to be not more than:

0.05MPa×0.02％/5＝0.002kPa

If select for use ± and the differential pressure transmitter of 1kPa, then its fiducial error is:

0.002kPa/2kPa＝0.1％

Promptly the differential pressure transmitter of Xuan Zeing should be not less than 0.1 grade.

2) application process is:

To first measurement point (0.05MPa), on two-piston, place about specific weight m that can produce 0.05MPa pressure respectively ₁And m ₂, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston corresponding valve that at first reaches the working position, continue to boost to another piston and also reach the working position.Make two-piston all reach duty, that is, and piston arrives assigned address and according to the regulation rotational speed in the rules, the differential pressure value that reads on the differential pressure transmitter 3 is Δ P.

Then have: $\frac{m_1\mathrm{<figure-callout\; id="1"\; label="g\; A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">g</figure-callout>}}{A_{}}=\frac{m_2\mathrm{<figure-callout\; id="2"\; label="g\; A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">g</figure-callout>}}{A_{}}+\mathrm{\&Delta;P}$

So: $A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1,$ Be the useful area of tested piston 2.

As the influence of need consideration aerostatic buoyancy, computing formula can be written as:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1(1+\frac{{\mathrm{\&rho;}}_k}{{\mathrm{\&rho;}}_f})}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

In the formula:

ρ _k---atmospheric density;

ρ _f---the counterweight density of material;

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area.

Later measurement point is identical with the first measurement point method.

M in the formula ₁And m ₂The quality that all contains piston (or ball float) and union piece thereof, below identical.

Embodiment 2 (correction of static pressure error)

A kind of pressure meter effective area measuring device, as shown in Figure 1, be applied to the effective area measuring of piston gage, comprise standard piston 1, tested piston 2, pressure source 4, differential pressure measuring installation 3, differential pressure measuring installation 3 is selected differential pressure transmitter 3 for use, wherein, standard piston 1 joins with differential pressure transmitter 3 positive pressure sides, and is connected with pressure source 4 by the first valve K1; Tested piston 2 joins with differential pressure transmitter 3 negative pressure ends, and is connected with pressure source 4 by the second valve K2.

Application process is:

To arbitrary measurement point, on two-piston, place about specific weight m that can produce predetermined pressure respectively ₁And m ₂, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston corresponding valve that at first reaches the working position, make piston reach duty, and the differential pressure value that reads on the differential pressure transmitter 3 is Δ P _aContinue to boost to another piston and also reach the working position.Make two-piston all reach duty, the differential pressure value that reads on the differential pressure transmitter 3 is Δ P _bThen:

Actual differential pressure value is:

ΔP＝ΔP _b-ΔP _a

Tested piston at the useful area of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

In the formula:

ρ _k---atmospheric density;

ρ _f---the counterweight density of material;

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area.

M in the formula ₁And m ₂The quality that all contains piston and union piece thereof.

Embodiment 3 (gas (liquid) post difference modification method 1)

A kind of pressure meter effective area measuring device, as shown in Figure 2, be applied to the effective area measuring of piston gage, comprise standard piston 1, tested piston 2, pressure source 4, differential pressure measuring installation 3, differential pressure measuring installation 3 is selected differential pressure transmitter 3 for use, wherein, standard piston 1 joins with the positive pressure side of differential pressure transmitter, and is connected with pressure source 4 by the first valve K1; Tested piston 2 joins with differential pressure transmitter negative pressure end, and is connected with pressure source 4 by the second valve K2.

Because the piston structure difference, the lower surface of piston 1 is than the high h in the lower surface of piston 2.

Application process is:

To arbitrary measurement point, on two-piston, place about specific weight m that can produce predetermined pressure respectively ₁And m ₂, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston corresponding valve that at first reaches the working position, continue to boost to another piston and also reach the working position.Make two-piston all reach duty, the differential pressure value that reads on the differential pressure transmitter 3 is Δ P.Then:

Tested piston at the useful area of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-(\mathrm{\&Delta;P}-\mathrm{\&rho;hg})A_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

In the formula:

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area.

ρ---the density of system works medium under working pressure.

Embodiment 4 (fluid column difference modification method 2)

A kind of pressure meter effective area measuring device, as shown in Figure 2, be applied to the effective area measuring of piston gage, comprise standard piston 1, tested piston 2, pressure source 4, differential pressure measuring installation 3, differential pressure measuring installation 3 is selected differential pressure transmitter 3 for use, wherein, standard piston 1 joins with the positive pressure side of differential pressure transmitter, and is connected with pressure source 4 by the first valve K1; Tested piston 2 joins with differential pressure transmitter negative pressure end, and is connected with pressure source 4 by the second valve K2.

Because the piston structure difference, the lower surface of piston 1 is than the high h in the lower surface of piston 2.

Application process is:

Piston-type pressure with 6MPa is counted example.

An at first selected lower spot pressure (as 1MPa) is a starting point.On two-piston, place about specific weight m that can produce starting point pressure (1MPa) respectively ₁₀And m ₂₀, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston corresponding valve that at first reaches the working position, continue to boost to another piston and also reach the working position.Make two-piston all reach duty, the differential pressure value that reads on the differential pressure transmitter 3 is Δ P ₀

To arbitrary measurement point, on two-piston, place about specific weight m that can produce predetermined pressure respectively ₁₁And m ₂₁, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston corresponding valve that at first reaches the working position, continue to boost to another piston and also reach the working position.Make two-piston all reach duty, the differential pressure value that reads on the differential pressure transmitter 3 is Δ P ₁Then:

ΔP＝ΔP ₁-ΔP ₀

m ₁＝m ₁₁-m ₁₀

m ₂＝m ₂₁-m ₂₀

Tested piston at the useful area of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

In the formula:

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area.

Embodiment 5 (situation of a plurality of differential pressure gauges is suitable for pin-point accuracy grade piston)

A kind of pressure meter effective area measuring device, as shown in Figure 3, be applied to the effective area measuring of pin-point accuracy piston gage, the differential pressure measuring installation that comprises standard piston 1, tested piston 2, pressure source 4 and five parallel connections, five differential pressure measuring installations are selected differential pressure transmitter for use, wherein, standard piston 1 joins with five positive pressure sides of differential pressure transmitter respectively by valve K3-1～K3-5, is connected with pressure source 4 by valve K1; Tested piston 2 joins with five differential pressure transmitter negative pressure ends respectively by valve K4-1～K4-5, and is connected with pressure source 4 by valve K2.

1) at first selecting differential pressure transmitter, is example with 0.02 grade of (first-class) piston gage useful area measuring 0.25MPa.

0.25MPa 0.02 grade of (first-class) piston gage need 5 measurement point: 0.05MPa, 0.1MPa, 0.15MPa, 0.2MPa, 0.25MPa, the corresponding differential pressure transmitter of each measurement point

Measurement range: according to the piston gage vertification regulation, it is ± 0.2% that useful area of 0.02 grade of (first-class) piston and nominal value allow maximum deviation.

The maximal value of first measurement point Δ P is:

ΔP _max＝±0.2％×0.05MPa＝±0.1kPa

The measurement range of first differential pressure transmitter should be less than 0～± 0.1kPa.

The maximal value of second measurement point Δ P is: Δ P _Max=± 0.2kPa

The measurement range of second differential pressure transmitter should be less than 0～± 0.2kPa.

The maximal value of the 3rd measurement point Δ P is: Δ P _Max=± 0.3kPa

The measurement range of second differential pressure transmitter should be less than 0～± 0.3kPa.

The maximal value of four measuring point Δ P is: Δ P _Max=± 0.4kPa

The measurement range of second differential pressure transmitter should be less than 0～± 0.4kPa.

The maximal value of the 5th measurement point Δ P is: Δ P _Max=± 0.5kPa

The measurement range of second differential pressure transmitter should be less than 0～± 0.5kPa.

Anti-static pressure: should be not less than piston gage and measure upper limit 0.25MPa.

Class of accuracy: 0.02 grade of (first-class) piston effective area permissible error is 0.01%, requirement is ignored by the uncertainty that the differential pressure transmitter measuring error causes, then the measuring error of differential pressure transmitter should cause 1/5 of uncertainty less than 0.02 grade of (first-class) piston effective area permissible error.

To first measurement point, require the permissible error of differential pressure transmitter to be not more than:

0.05MPa×0.01％/5＝0.001kPa

If select for use ± and the differential pressure transmitter of 0.1kPa, then its fiducial error is:

0.001kPa/0.2kPa＝0.5％

Promptly the differential pressure transmitter of Xuan Zeing should be not less than 0.5 grade.

The differential pressure transmitter that can calculate second～the 5th measurement point equally all is not less than 0.5 grade.

2) application process is:

To first measurement point (0.05MPa), open the valve K3-1 at the differential pressure transmitter two ends of the first measurement point correspondence, K4-1 closes K5-1; Close the valve K3-2～K3-5 at the differential pressure transmitter two ends of other measurement point correspondence, K4-2～K4-5 opens K5-2～K5-5;

On two-piston, place about specific weight m that can produce 0.05MPa pressure respectively ₁And m ₂, 4 pairs of two-pistons of pressure source are exerted pressure, and close the piston that at first reaches the working position and the valve between the pressure source, continue to boost to another piston and also reach the working position.Make two-piston all reach duty, that is, and piston arrives assigned address and according to the regulation rotational speed in the rules, the differential pressure value that reads on the differential pressure transmitter 3-1 is Δ P.

Then the useful area of the tested piston 2 of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

Later measurement point is identical with the first measurement point method.

Embodiment 6 (piston survey ball float)

A kind of pressure meter effective area measuring device, as shown in Figure 4, measure the manometric useful area of float-ball type with piston gage, comprise standard piston 1, tested ball pneumatic dead wieght tester 5, differential pressure measuring installation 3, pressure source 4, source of the gas 7, differential pressure measuring installation is selected differential pressure pick-up for use, and promptly 3 is differential pressure pick-up, and the useful area of standard piston 1 is known as A ₁, useful area the unknown of tested ball pneumatic dead wieght tester 5 is A ₂

Application process is:

To arbitrary measurement point, open valve K3, K5 closes K4.

On piston and ball float, place about specific weight m that can produce predetermined pressure respectively ₁And m ₂, open the source of the gas 7 of ball pneumatic dead wieght tester, 4 pairs of pistons of pressure source are exerted pressure, and when piston reaches the working position, make piston and ball float all in running order.

Valve-off K5 opens K4.

The differential pressure value that reads on the differential pressure transmitter 3 is Δ P, then:

Tested ball float at the useful area of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

Embodiment 7 (ball float survey ball float)

A kind of pressure meter effective area measuring device, as shown in Figure 5, mensuration for the float-ball type pressure meter effective area, comprise standard float-ball type pressure gauge 6, tested ball pneumatic dead wieght tester 5, differential pressure measuring installation 3, source of the gas 7, differential pressure measuring installation is selected differential pressure transmitter for use, promptly 3 is differential pressure transmitter, and the useful area of standard float-ball type pressure gauge 6 is known as A ₁, useful area the unknown of tested ball pneumatic dead wieght tester 5 is A ₂

Application process is:

To arbitrary measurement point, open valve K5, close K3, K4.

On two ball floats, place about specific weight m that can produce predetermined pressure respectively ₁And m ₂, open the source of the gas 7 of ball pneumatic dead wieght tester, make two ball floats all in running order.

Valve-off K3 closes K5, opens K4. again

Read the differential pressure value Δ P on the differential pressure transmitter 3, then:

Tested ball float at the useful area of this measurement point is:

$A_2=\frac{m_{2}g}{m_{1}g-\mathrm{\&Delta;}{\mathrm{PA}}_1}{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="A200910014002E00141.png,A200910014002E00142.png"\; state="\{\{state\}\}">A</figure-callout>}}_1$

Claims (8)

1. a pressure meter effective area measuring method by the fixed tested pressure gauge of normal pressure instrumentation, comprises measuring process and calculation procedure, it is characterized in that: the step that comprises the differential pressure between measurement standard pressure gauge and the tested pressure gauge in the measuring process.

2. pressure meter effective area measuring method according to claim 1, it is characterized in that: the step of pressure reduction realizes as follows between described measurement standard pressure gauge and the tested pressure gauge: be provided with at least one differential pressure measuring installation between normal pressure meter and tested pressure gauge, measure differential pressure.

3. pressure meter effective area measuring method according to claim 1 and 2 is characterized in that: described measuring process is:

(1) respectively normal pressure meter and tested pressure gauge are connected to differential pressure measuring installation and pressure source;

(2) placing quality on the normal pressure meter is m ₁Counterweight, placing quality on the tested pressure gauge is m ₂Counterweight;

(3) under the duty, it is Δ P that differential pressure measuring installation records differential pressure;

Described calculation procedure is:

Under the duty: $\frac{m_{1}g}{A_1}=\frac{m_{2}g}{A_2}+\mathrm{\&Delta;P}$

So: $A_2=\frac{m_{2}g}{m_{1}g-{\mathrm{\&Delta;PA}}_1}{A}_1$

In the formula: g---acceleration of gravity;

Δ P---the differential pressure between the two-piston system;

A ₁---the useful area of normal pressure meter;

A ₂---tested manometric useful area;

m ₁And m ₂---put on two manometric specific weight quality, contain piston or ball float and union piece quality thereof.

4. pressure meter effective area measuring method according to claim 3, it is characterized in that: described measuring process also comprises the step of the static pressure error of eliminating differential pressure measuring installation: at each gaging pressure point, the differential pressure measuring installation two ends are communicated with, and measuring its static pressure error is Δ P _a, the differential pressure measuring installation two ends are cut off, measurement standard pressure gauge and tested manometric differential pressure are Δ P again _b, Δ P=Δ P then _b-Δ P _a

5. pressure meter effective area measuring method according to claim 3, it is characterized in that: described measuring process also comprises the step of revising normal pressure meter and tested manometric lower surface difference in height: stipulate that at first a spot pressure is a starting point, places counterweight m on the normal pressure meter ₁₀, on tested pressure gauge, place counterweight m ₂₀, recording this differential pressure is Δ P ₀At measurement point the normal pressure meter is placed counterweight m ₁₁, tested pressure gauge places counterweight m ₂₁, recording this differential pressure is Δ P ₁Δ P=P then ₁-Δ P ₀, m ₁=m ₁₁-m ₁₀, m ₂=m ₂₁-m ₂₀

6. realize the pressure meter effective area measuring device of the described method of claim 1, normal pressure meter and tested pressure gauge is communicated with a pressure source or/and source of the gas is characterized in that: between normal pressure meter and tested pressure gauge, be provided with at least one differential pressure pick-up unit.

7. pressure meter effective area measuring device according to claim 6, it is characterized in that: the first valve K1 is arranged between normal pressure meter and pressure source, the second valve K2 is arranged between tested pressure gauge and pressure source, the 3rd valve K3 is arranged between normal pressure meter and differential pressure measuring installation, the 4th valve K4 is arranged between tested pressure gauge and differential pressure measuring installation, between normal pressure meter and tested pressure gauge, with differential pressure measuring installation be parallel with the 5th valve K5.

8. pressure meter effective area measuring device according to claim 7 is characterized in that: described differential pressure measuring installation is differential pressure transmitter or differential pressure pick-up.

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