CN103398747B - A kind of gas meter and application process thereof - Google Patents

Abstract

The invention provides a kind of gas meter, be included in the water conservancy diversion filtering element and laminar flow shedder that set gradually along airflow direction in tubular shell, in the outside of tubular shell, differential pressure pickup and data processing unit be installed; Radially offer two place's pressure passages at the sidewall of tubular shell, correspond respectively to two induction end of differential pressure pickup, described two place's pressure passages lay respectively at front and the rear of laminar flow shedder; The main body of described laminar flow shedder is cross section is latticed many micro channels, and each micro channel is parallel and mutually isolated, to make air-flow to be measured with laminar condition by this laminar flow shedder.The present invention has the advantage that volume is little, working stability, the accuracy of measuring are high.

Description

A kind of gas meter and application process thereof

Technical field

The present invention relates to a kind of gas flow metering device.

Background technology

In the market for rock gas trade settlement aspect, in, low discharge metering main current flow gauge be diaphragm gas meter.

The defect of diaphragm gas meter: volume is large, installs difficulty; Complex structure, failure rate is high; Transmission membrane limited strength, can not be high pressure resistant; There is no Temperature and Pressure Correction, so accuracy is low.

Summary of the invention

The invention provides a kind of gas meter, volume is little, working stability, the accuracy of measuring be high.

The solution of the present invention is as follows:

A kind of gas meter, is included in the water conservancy diversion filtering element and laminar flow shedder that set gradually along airflow direction in tubular shell, is provided with differential pressure pickup and data processing unit in the outside of tubular shell; Radially offer two place's pressure passages at the sidewall of tubular shell, correspond respectively to two induction end of differential pressure pickup, described two place's pressure passages lay respectively at front and the rear of laminar flow shedder; The main body of described laminar flow shedder is cross section is latticed many micro channels, and each micro channel is parallel and mutually isolated, to make air-flow to be measured with laminar condition by this laminar flow shedder.

Based on above-mentioned basic technical scheme, the present invention has also done following optimization and has limited and improve:

Above-mentioned laminar flow shedder can adopt stainless steel double-layer plate to roll and form, wherein one deck of described stainless steel double-layer plate is that thickness is less than 0.1mm corrugated plate, another layer is less than the smooth plates of corrugated plate for thickness, form described many micro channels between the ripple of corrugated plate and smooth plates, the ripple radius of corrugated plate is 1-3mm.

Above-mentioned laminar flow shedder also can adopt multiple stainless steel capillary boundling to form, and the caliber of stainless steel capillary is 1 ~ 3mm, and wall thickness is 0.05 ~ 0.15mm.

Above-mentioned laminar flow shedder is directly fixed in a sleeve pipe, is installed in described tubular shell by this sleeve pipe.Sleeve pipe inner laminar flow shedder two ends respectively have several pressure ports of a circle, and two circle pressure ports lead to two place's pressure passages of tubular shell respectively.

Also be provided with absolute pressure sensor in the outside of tubular shell, pressure passage shared by its pressure survey probe and differential pressure pickup.

Also temperature sensor is installed in the outside of tubular shell, the corresponding temp probe offering passage cut-in temperature sensor of the sidewall of tubular shell.

Application above-mentioned gas flowmeter carries out gas flow measurement, can with reference to following steps:

(1) install with gas flow measurement scope to be measured adapt laminar flow shedder, according to formula Δ P=K ₁μ Q+K ₂ρ Q ²demarcate this gas meter, draw COEFFICIENT K ₁, K ₂value; Wherein, Δ P is the pressure differential at laminar flow shedder two ends, and Q is real-time traffic, and μ is the kinetic viscosity of fluid media (medium);

(2) this gas meter of airflow passes to be measured, pressure differential deltap P before and after the acquisition laminar flow shedder of gas meter, calculates real-time traffic Q according to the following formula

$Q=\sqrt{{\left(\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}}\right)}^2+\frac{\mathrm{\ΔP}}{K_2\mathrm{\ρ}}}-\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}},$ Wherein:

The density of tested gas under ρ-condition of work;

K ₁, K ₂-demarcate the coefficient relevant with laminar flow flowmeter physical dimension obtained;

The kinetic viscosity of μ-fluid media (medium).

Tool of the present invention has the following advantages:

This small product size is little, and level, vertical direction all can conveniently be installed; Overall installation size is only equivalent to the length of the domestic water meter of DN25.

This flowmeter accuracy of measuring is high, compact overall structure, and outside does not connect spool, and inside does not have moving element, failure rate is low; Can work under high pressures compared with diaphragm gas meter.

The compact overall structure of this product design, rationally distributed.According to application demand, can in little space integrated pressure, temperature and flow measuring element, realize temperature, the pressure various function such as compensate function and display, storage and output.

Devise laminar flow element sleeve pipe, be convenient for changing laminar flow shedder, to adapt to different flow measurement range.

Respectively have several pressure ports of a circle at sleeve pipe inner laminar flow shedder two ends further, two circle pressure ports lead to two place's pressure passages of tubular shell respectively accordingly, define ring casing pressure, can evenly pressure, and not easily block.

Accompanying drawing explanation

Fig. 1 is gas meter principle of work schematic diagram of the present invention.

Wherein, 1-flow integrator; 2-water conservancy diversion filtering element; 3-laminar flow shedder; 4-flowmeter tubular shell; 5-temp probe.

Fig. 2 is laminar flow shedder diagrammatic cross-section.

Embodiment

Gas meter principle of work of the present invention is as shown in Figure 1: measured gas flow, when flowmeter, first through water conservancy diversion filtering element, filters out the impurity in gas, and carries out rectification to air-flow, makes flowing stable.Air-flow, through laminar flow shedder, owing to there is frictional resistance, therefore produces the pressure loss at its two ends, and when the Reynolds number of fluid flowing is less than 2300, this pressure loss is directly proportional to gas flow rate.Namely

Velocity formula: $\stackrel{-}{v}=\frac{c}{\mathrm{\μ}}\·\mathrm{\ΔP}$

In formula: the mean flow rate of-fluid;

The pressure differential at Δ P-laminar flow shedder two ends;

The kinetic viscosity of μ-fluid media (medium)

The constant that c-is relevant with physical dimension.

Flow formula: $\stackrel{-}{Q}=A\·\frac{c}{\mathrm{\μ}}\·\mathrm{\ΔP}$

In formula: average discharge in-pipeline

A-conduit cross-sectional area.

In fact, gas produces two parts resistance when flowing through laminar flow shedder: a part is the friction force because gas viscosity causes, this friction force relevant with the kinetic viscosity of fluid and under low flow velocity condition (Reynolds number is less than 2300) be directly proportional to flow velocity; Another part is the inertial force because throttling causes, the generation of throttling is that the grain direction caused due to laminar flow shedder material wall thickness changes and the stagnation of fluid particle, relevant with the density of fluid according to this inertial force of Bernoulli equation, and to square being directly proportional of flow velocity.It is poor that this two parts resistance sum is the static pressure that gas produces at laminar flow shedder two ends, and its mathematic(al) representation is as shown in (2) formula.

ΔP=K ₁μQ+K ₂ρQ ²（3）

In formula: the density of tested gas under ρ-condition of work;

K ₁, K ₂-the coefficient relevant with laminar flow flowmeter physical dimension.

(3) formula is solved, obtains the expression formula of the volume flow Q under working condition.

$Q=\sqrt{{\left(\frac{K_1\mathrm{\μ}}{{2K}_2\mathrm{\ρ}}\right)}^2+\frac{\mathrm{\ΔP}}{K_2\mathrm{\ρ}}}-\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}}---\left(4\right)$

An embodiment as shown in Figure 1, 2, this gas meter, be included in the water conservancy diversion filtering element and laminar flow shedder that set gradually along airflow direction in tubular shell, laminar flow shedder is directly fixed in a sleeve pipe, is installed in described tubular shell by this sleeve pipe.In the outside of tubular shell, differential pressure pickup and data processing unit are installed; Radially offer two place's pressure passages at the sidewall of tubular shell, correspond respectively to two induction end of differential pressure pickup, this two places pressure passage lays respectively at front and the rear of laminar flow shedder; The main body of laminar flow shedder is cross section is latticed many micro channels, and each micro channel is parallel and mutually isolated, to make air-flow to be measured with laminar condition by this laminar flow shedder.

Also be provided with absolute pressure sensor and temperature sensor in the outside of tubular shell, pressure passage shared by the pressure survey probe of absolute pressure sensor and differential pressure pickup, the corresponding temp probe offering passage cut-in temperature sensor of the sidewall of tubular shell.

Laminar flow shedder of the present invention at least can have following two kinds of production methods:

Method for making 1: laminar flow element is different by two-layer shape, the stainless sheet steel that thickness is less than 0.1mm rolls and forms.Wherein one deck is through the corrugated plate of special thermal treatment and rolling mill practice making, and another layer is the smooth plates that thickness is less.Requirement is: when air-flow is through laminar flow element, and the Reynolds number of its each aperture inner fluid flowing is less than 2300, makes flowing be in laminar condition.Reynolds number (Re relevant to fluid viscosity, flow velocity and micro-pore diameter _d=vd/ μ).Measuring media according to flow measurement range, can calculate and determine that micro-pore diameter is to make Reynolds number within 2300 after determining.

Method for making 2: laminar flow element is formed by multiple stainless steel capillary boundling.The caliber scope of stainless steel capillary: (1-3) mm, wall thickness range: (0.05-0.15) mm.Requirement is: when air-flow is through laminar flow element, and the Reynolds number of its each aperture inner fluid flowing is less than 2300, makes flowing be in laminar condition.

Based on aforementioned principles, use this gas meter first, can first demarcate this gas meter, namely install with gas flow measurement scope to be measured adapt laminar flow shedder, according to formula Δ P=K ₁μ Q+K ₂ρ Q ²demarcate this gas meter, wherein, Δ P is the pressure differential at the laminar flow shedder two ends recorded, and Q is known real-time traffic, and μ is the kinetic viscosity of known fluid media (medium); Draw COEFFICIENT K ₁, K ₂value;

Then can carry out gas flow measurement: this gas meter of airflow passes to be measured, pressure differential deltap P before and after the acquisition laminar flow shedder of gas meter, calculate real-time traffic Q according to the following formula

$Q=\sqrt{{\left(\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}}\right)}^2+\frac{\mathrm{\ΔP}}{K_2\mathrm{\ρ}}}-\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}},$ Wherein:

The density of tested gas under ρ-condition of work;

K ₁, K ₂-demarcate the coefficient relevant with laminar flow flowmeter physical dimension obtained;

The kinetic viscosity of μ-fluid media (medium).

Claims (5)

1. a gas meter, is characterized in that: be included in the water conservancy diversion filtering element and laminar flow shedder that set gradually along airflow direction in tubular shell, be provided with differential pressure pickup and data processing unit in the outside of tubular shell; Radially offer two place's pressure passages at the sidewall of tubular shell, correspond respectively to two induction end of differential pressure pickup, described two place's pressure passages lay respectively at front and the rear of laminar flow shedder; The main body of described laminar flow shedder is cross section is latticed many micro channels, and each micro channel is parallel and mutually isolated, to make air-flow to be measured with laminar condition by this laminar flow shedder;

Described laminar flow shedder adopts stainless steel double-layer plate to roll and forms, wherein one deck of described stainless steel double-layer plate is that thickness is less than 0.1mm corrugated plate, another layer is less than the smooth plates of corrugated plate for thickness, form described many micro channels between the ripple of corrugated plate and smooth plates, the ripple radius of corrugated plate is 1-3mm.

2. gas meter according to claim 1, is characterized in that: described laminar flow shedder is directly fixed in a sleeve pipe, and this sleeve pipe is installed in described tubular shell; Sleeve pipe inner laminar flow shedder two ends respectively have several pressure ports of a circle, and two circle pressure ports lead to two place's pressure passages of tubular shell respectively.

3. gas meter according to claim 1, is characterized in that: be also provided with absolute pressure sensor in the outside of tubular shell, and pressure passage shared by its pressure survey probe and differential pressure pickup.

4. gas meter according to claim 1, is characterized in that: be also provided with temperature sensor in the outside of tubular shell, the corresponding temp probe offering passage cut-in temperature sensor of the sidewall of tubular shell.

5. apply gas meter as claimed in claim 1 and carry out a method for gas flow measurement, comprise the following steps:

(1) install with gas flow measurement scope to be measured adapt laminar flow shedder, according to formula Δ P=K ₁μ Q+K ₂ρ Q ²demarcate this gas meter, draw COEFFICIENT K ₁, K ₂value; Wherein, Δ P is the pressure differential at laminar flow shedder two ends, and Q is real-time traffic, and μ is the kinetic viscosity of fluid media (medium);

(2) this gas meter of airflow passes to be measured, pressure differential deltap P before and after the acquisition laminar flow shedder of gas meter, calculates real-time traffic Q according to the following formula

$Q=\sqrt{{\left(\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}}\right)}^2+\frac{\mathrm{\Δ}P}{K_2\mathrm{\ρ}}}-\frac{K_1\mathrm{\μ}}{2K_2\mathrm{\ρ}},$ Wherein:

The density of tested gas under ρ-condition of work;

K ₁, K ₂-demarcate the coefficient relevant with laminar flow flowmeter physical dimension obtained;

The kinetic viscosity of μ-fluid media (medium).