CN2462359Y - Directly reading orifice plate flowmeter - Google Patents

Abstract

The utility model relates to a directly reading orifice plate flow meter, which is composed of a flow measurement throttling device 1, a flow guide tube 5 connected to both sides of the flow measurement throttling device 1, a flow limiting orifice plate 6 connected in series to the flow guide tube 5, and a glass rotor flow meter 4. The directly reading orifice plate flow meter has the advantages of simple structure, convenient installation, visual display, stable and reliable performance, no need of power supplies, and safe use.

Description

The direct-reading orifice flowmeter

The utility model relates to orifice flowmeter, is the flowmeter of fluid (liquid, the gas) metering of industry such as a kind ofly be mainly used in oil, chemical industry, water conservancy, electric power, feedwater, pharmacy, brewage.

Existing orifice flowmeter, be by being arranged on ducted flow measurement orifice plate restriction device 1 (abbreviation restriction device), being connected the pressure pipe 2 of restriction device 1 both sides and the differential pressure transmitter 3 that is connected on the pressure pipe 2 constitutes as shown in Figure 1, its principle of work is: when the fluid that is full of pipeline is flowed through ducted restriction device 1, near restriction device 1, form local contraction, flow velocity increases, and produces its big or small Δ P=P1-P2 of being of static pressure difference Δ P (being called differential pressure usually) in the upstream side and the downstream of restriction device 1.Under known situation about technological parameter and restriction device characterisitic parameter, the relation that can derive between flow and the differential pressure according to flow continuity principle and Bernoulli equation is as follows: $q_m=\frac{C}{\sqrt{1-{\mathrm{\&beta;}}^4}}\mathrm{\&epsiv;}\frac{\mathrm{\&pi;}}{4}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="Y0121144900061.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\sqrt{2\&times;\mathrm{\&Delta;P}\&times;\mathrm{\&rho;}}$ $q_v=\frac{q_m}{\mathrm{\&rho;}}$ In the formula: the C-efflux coefficient,

The throttle diameter of restriction device under the d-condition of work, m

Internal diameter of the pipeline under the D-condition of work, m

q _m-mass rate, kg/s

q _v-volumetric flow rate, m ³/ s

β-diameter is than d/D,

The density of ρ-fluid, kg/m ³

ε-expansibility factor, dimensionless

Δ P-restriction device upstream side static pressure P ₁With downstream static pressure P ₂Poor, the measuring method of the existing orifice flowmeter of Pa is to adopt differential pressure transmitter to record differential pressure Δ P, obtains fluid flow in the pipeline according to above-mentioned formula again.

This kind metering system is full of fluid but does not have fluid and flows through in the pressure pipe 2, the objective result of measurement (flow value) obtains through conversion of signals by measuring intermediate value Δ P again, and measurement result shows directly perceived inadequately; And transfer process is loaded down with trivial details, complicated, is subjected to circuit design level, power supply quality and extraneous factor to influence bigger.In addition, but do not have fluid and flow through owing to be full of fluid in the pressure pipe 2, ducted impurity easily is deposited on and causes pressure pipe 2 to stop up in the pressure pipe 2 in the use, influences the normal use of flowmeter; And, need uninterrupted power supply in the differential pressure transmitter 3 instrumentation processes, in case power supply is interrupted, then can't realize normal flow metering.So existing orifice flowmeter is unsatisfactory, and cost is very high.

The purpose of this utility model provides a kind of simple in structure, and performance is good, and cost is low, installation, easy to use, but the orifice flowmeter of direct-reading.

The utility model is made of flow measurement differential pressure producer 1, the drainage tube 5 that is connected flow measurement differential pressure producer 1 both sides, restriction orifice 6 and the glass rotameter 4 that is connected on the drainage tube 5.

Principle of work of the present utility model is: the drainage tube 5 that between the upstream and downstream of flow measurement differential pressure producer 1 both sides, is provided with, and under Δ P effect, there is fluid to flow through in the drainage tube 5, as follows according to the flow that aforementioned formula can be obtained in the drainage tube 5: $q_{1m}=\mathrm{\&xi;}\frac{C}{\sqrt{1-{{\mathrm{\&beta;}}_1}^4}}\mathrm{\&epsiv;}\frac{\mathrm{\&pi;}}{4}{{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="Y0121144900061.png"\; state="\{\{state\}\}">d</figure-callout>}}_1}^2\sqrt{2\mathrm{\&Delta;P}\&times;\mathrm{\&rho;}}$ $q_{1v}=\frac{q_{1m}}{\mathrm{\&rho;}}$

In the formula: q _1m, q _1vFlow in the-drainage tube 5, kg/s, m ³/ s,

ξ-flow correction coefficient,

β ₁D is compared in-aperture ₁/ D ₁,

d ₁-restriction orifice 6 internal diameters, m

D ₁-drainage tube 5 internal diameters, m,

Other symbol implications as previously mentioned.

When having fluid to flow through in the process pipeline, be subjected to the throttling action of restriction device 1, form differential static pressure, its value Δ P=P1-P2 in the upstream side and the downstream of restriction device 1; Under the effect of differential static pressure, a part of fluid enters drainage tube 5 by the upstream side of restriction device 1, flows back to the downstream of restriction device 1 through drainage tube 5 and glass rotameter 4.Flow value in the drainage tube 5 is directly read by glass rotameter 4, and its size is by the inner diameter d of restriction orifice 6 ₁Determine, by adjusting d ₁Flow in the control drainage tube 5 makes q _1m(q _1v) and q _m(q _v) proportion relation.Like this, by measuring the fluid flow in the drainage tube 5, just can reach the purpose of the fluid flow in the measurement line, the scale of glass rotameter 4 marks by the flow in the process pipeline, what its reading reflected is exactly desired value to be measured, the flow value in the established technology pipeline.

The utility model direct-reading orifice flowmeter is compared with existing orifice flowmeter, though show as on the structure is to have replaced differential pressure transmitter 3 with glass rotameter 4, set up a restriction orifice 6, but its measuring principle and performance fruit are distinct really: have fluid to flow through in the drainage tube 5 of this direct-reading orifice flowmeter, the objective result of measuring (flow value) can directly show by glass rotameter 4, need not pass through conversion of signals, avoid being subjected to the influence of extraneous factor; Owing to have fluid to flow through in the drainage tube 5, under the souring of fluid, drainage tube is difficult for stopping up; Need not power the influence that not be interrupted by power supply; Fluid flow in the drainage tube 5 and the proportional relation of the fluid flow in the process pipeline, its proportionate relationship depends on the inner diameter d of restriction orifice 6 ₁, therefore need only adjust d ₁, just can reach different measurement ranges; Glass rotameter 4 is standard products, its dependable performance, and simple installation, thus the installation of direct-reading orifice flowmeter is greatly simplified, performance is more stable.

Fig. 1 is existing orifice flowmeter structure principle chart.

Fig. 2 is the utility model structure principle chart.

Fig. 3 is that the utility model is executed routine structural representation.

Shown in accompanying drawing 2, the utility model is made of flow measurement differential pressure producer 1, the drainage tube 5 that is connected orifice plate 10 both sides of flow measurement differential pressure producer 1, restriction orifice 6 and the glass rotameter 4 that is connected on the drainage tube 5.

Shown in accompanying drawing 3, the two ends of glass rotameter 4 are connected with drainage tube 5 by joint flange 40,40 '; Restriction orifice 6 is installed between the joint flange 40/40 '.Be to install and easy to maintenance, drainage tube 5 is provided with stop valve 7,7 ', and stop valve 7,7 ' setting can realize the maintenance that do not stop production.

The utility model cost is low, every hundreds of unit of glass rotameter, and every unit up to ten thousand of employed differential pressure transmitter in the existing orifice flowmeter; Simple in structure, easy for installation, only need during installation glass rotameter is connected and get final product with two flanges; Intuitive display, glass rotameter are the direct-reading Displaying Meters, the actual flow in the direct corresponding pipeline of its reading; Applied widely, be particularly useful for the occasion of big caliber, big flow; Stable performance, maintenance capacity is few, and because one-piece construction is simple, its performance only depends on the bore size and the planform of restriction device and restriction orifice, and it is little influenced by external condition, and restriction device and restriction orifice need not keep in repair, and glass rotameter is easy to maintenance; Because this direct-reading orifice flowmeter does not need power supply, so not only can save the energy, save track laying, power supply facilities and managerial cost thereof, and also safe in utilization, can not produce explosion danger, can not produce because of the sudden power influence.

Claims (2)

1, direct-reading orifice flowmeter is characterized in that being made of flow measurement differential pressure producer (1), the drainage tube (5) that is connected flow measurement differential pressure producer (1) both sides, restriction orifice (6) and the glass rotameter (4) that is connected on the drainage tube (5).

2, direct-reading orifice flowmeter according to claim 1 is characterized in that the two ends of glass rotameter (4) are connected with drainage tube (5) by joint flange (40,40 '); Restriction orifice (6) is installed between the joint flange (40/40 '), and drainage tube (5) is provided with stop valve (7,7 ').

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