CN201262560Y - V-wimble flow measuring device based on MEMS sensor - Google Patents

Abstract

The utility model relates to a flow measuring device, in particular to a V-taper flow measuring device based on an MEMS sensor. The device is composed of a flange, a measuring tube, a support frame, an MEMS sensitive core, a packaging structure, a positive pressure tapping, a negative pressure tapping, a V-typed taper component and a signal wire. In the device, the MEMS sensitive core is arranged inside the V-typed taper, the pressure tappings are also arranged inside the measuring tube and the structure of the traditional V-taper flow meter with the need of leading the pressure to outside of the tube is canceled. In accordance with a mathematical relation model of flow-pressure difference and the actual demarcation of the site, the dynamic and steady-state measurements to the flow are realized. The measuring device solves the problems of the traditional V-taper flow meter, such as poor dynamic characteristics, large error and high loss. Meanwhile, the utility model creates necessary conditions for realizing standardization of the V-taper flow meter and is good for the popularization and application of the V-taper flow meter.

Description

A kind of V taper flow meter based on the MEMS sensor

Technical field

The utility model relates to a kind of fluid flow rate measurement apparatus, relate in particular to a kind of based on the MEMS sensor to carrying out the V conical flow measuring device of the high response of low-loss in the pipe.

Background technology

The tapered flowmeter of V be utilize coaxial be installed in the measuring channel V-type point circular cone with fluid little by little throttling be retracted to the inner edge wall of pipeline, measure flow by the pressure differential of measuring before and after this V-type inner cone.At present, the V cone flow meter and the standardization of being unrealized.

Traditional V cone flow meter comprises two pressure tappings on coaxial mounted sharp cone and the measuring tube in measuring tube.The common volume of this type of flowmeter is bigger, and is more to the energy loss that pipeline brings, and differential pressure generating separates with the differential pressure transporting device, needs special pipeline that pressure differential is guided to outside the pipe and compares.This on the one hand easy accumulated gas and dirty dirt influence the steady state measurement precision of flowmeter, and increase the maintenance maintenance cost; Because the restriction of the response frequency of common differential pressure transmitter makes that the dynamic response of flowmeter is very poor, often can not satisfy the needs at some Industry Control scenes, and this type of differential pressure transmitter processing cost is higher on the other hand.

Summary of the invention

The purpose of this utility model is to provide a kind of V taper flow meter based on the MEMS sensor, and it is poor to solve traditional V cone flow meter dynamic perfromance, and error is big, problems such as loss height, simultaneously, realize standardization for the V cone flow meter and created necessary condition, help applying of V cone flow meter.

The technical solution of the utility model is: based on the V taper flow meter of MEMS sensor, this device is made of MEMS sensitive core body 4, encapsulating structure 5, the signal wire 8 of flange 1, measuring tube 2, bracing frame 3, V-type cone assembly 6, negative pressure tappings 7, positive pressure tappings 9 and Sensor section; Measuring tube 2 two ends manage blue 1; V-type cone assembly 6 is by bracing frame 3 coaxial measuring tube 2 inside that are fixed on; MEMS sensitive core body 4 is encapsulated in the encapsulating structure 5, places V-type cone assembly 6 inside or is embedded in V-type cone assembly 6 straight pipe walls or conical surface wall, and keep sealing; Positive pressure tappings 9 all is located on the V-type cone assembly 6 with negative pressure tappings 7, is positioned at measuring tube 2 inside; Two pressure pipes of MEMS sensitive core body 4 contact high pressure and low-pressure fluid by positive pressure tappings 9 with negative pressure tappings 7 respectively; Signal wire 8 with draw measuring tube 2 after MEMS sensitive core body 4 is connected.Described MEMS sensitive core body 4 is the little pressure resistance type of silicon, piezoelectric type or capacitance type minitype pressure/pressure reduction sensitive core body.The front end of described V-type cone assembly 6 is fixedlyed connected with bracing frame 3 one ends, and bracing frame 3 other ends are fixed on measuring tube 2 inwalls.Described encapsulating structure 5 upsides are fixed on the V-type cone assembly inwall, and downside communicates with positive pressure tappings 9 on the V-type cone assembly 6 and measures high pressure, and the right side communicates with negative pressure tappings 7 and measures low pressure, and the left side is connected with signal wire 8.

Principle of the present utility model is: according to Bernoulli equation as can be known, can produce the pressure differential signal corresponding to the flow size when fluid flows through V-type cone assembly 6, this signal is recorded by MEMS sensitive core body 4 and draws measuring tube 2 by signal wire 8.According to following flow---pressure reduction numerical relationship model and on-the-spot actual the demarcation, can realize dynamic and steady state measurement to flow.Its flow equation is:

$q_v=\frac{\mathrm{c\&epsiv;}}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\mathrm{\&pi;}}{4}\&CenterDot;{\mathrm{\&beta;}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="Y200820015114E00061.png,Y200820015114E00062.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\&CenterDot;\sqrt{2\mathrm{\&Delta;P}/{\mathrm{\&rho;}}_1}$

$q_m=\frac{\mathrm{c\&epsiv;}}{\sqrt{1-{\mathrm{\&beta;}}^4}}\&CenterDot;\frac{\mathrm{\&pi;}}{4}\&CenterDot;{\mathrm{\&beta;}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="Y200820015114E00061.png,Y200820015114E00062.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\&CenterDot;\sqrt{2\mathrm{\&Delta;P}/{\mathrm{\&rho;}}_1}$

In the formula: q _v---volumetric flow rate, m ³/ s

q _m---mass rate, kg/s

C---efflux coefficient

ε---expansibility factor

β---equivalent diameter ratio

D---measuring tube internal diameter under the operating mode

Δ P---pressure reduction

ρ ₁---operating mode density

The utility model is implanted measuring tube internal measurement pressure reduction with MEMS sensitive core body 4, do not need pressure is drawn measuring tube 2 outer comparing, do not exist pressure guiding pipe to lose along stroke pressure, therefore only need very weak throttling action can realize measuring, the permanent compression loss is low; Adopt the V-type cone to obtain pressure reduction, the repetition type is good, and range ratio is wide, and anti-dirty ability is strong, and signal stabilization is good, does not need the upstream straight length, and can realize higher signal level in less space length; Device of the present utility model has been cancelled traditional cloth impulse pipe engineering, has reduced manufacturing cost and maintenance and repair workload, has higher measuring accuracy; And all very little MEMS sensitive core body 4 of application quality and inertia is as sensor, and the time constant that pressure reduction measures is very little, so the kinetic measurement frequency is improved largely; Only need very little pressure reduction just can obtain measurement effect accurately, therefore reduced the structural volume of V-type cone greatly, help the standardization of V cone flow meter.The utility model can be applied to general fluid media (medium) conveying aspect, also can solve the problems of measurement of humid gas flow measurement and coke-oven gas, can also effectively finish the measurement to low static pressure, low flow rates of fluid.

The beneficial effects of the utility model are: compact conformation is reasonable, helps the standardized and popularized of V cone flow meter; Easy to use, be convenient to safeguard, do not need the impulse pipeline just can realize the low pressure loss of on-the-spot flow, minute-pressure is poor, high-acruracy survey.

Description of drawings

Fig. 1 is the synoptic diagram of the utility model embodiment 1;

Fig. 2 is the synoptic diagram of the utility model embodiment 2;

Fig. 3 is the synoptic diagram of the utility model embodiment 3.

Among the figure: 1, flange, 2, measuring tube, 3, bracing frame, 4, the MEMS sensitive core body, 5, encapsulating structure, 6V type cone assembly, 7, negative pressure tappings, 8, signal wire, 9, positive pressure tappings.

Embodiment

Embodiment 1

As shown in Figure 1, the front end of V-type cone assembly 6 is fixedlyed connected with bracing frame 3 one ends, and bracing frame 3 other ends are fixed on measuring tube 2 inwalls; MEMS sensitive core body 4 is encapsulated in and places V-type cone assembly 6 inside in the encapsulating structure 5; When the fluid in the measuring tube 2 is flowed through the V-type point circular cone of V-type cone assembly 6, fluid little by little throttling is retracted to the inner edge wall of pipeline, according to the bernoulli principle as can be known, produce the pressure differential corresponding to the flow size before and after this V-type cone, this pressure differential is recorded by MEMS sensitive core body 4 and draws measuring tube 2 by signal wire 8.According to flow-differential pressure numerical relationship model and on-the-spot actual the demarcation, can realize dynamic and steady state measurement to flow.

Embodiment 2

As shown in Figure 2, the front end of V-type cone assembly 6 is fixedlyed connected with bracing frame 3 one ends, and bracing frame 3 other ends are fixed on measuring tube 2 inwalls; MEMS sensitive core body 4 is encapsulated in the straight length tube wall that is embedded in V-type cone assembly 6 in the encapsulating structure 5, and keeps sealing with tube wall; When the fluid in the measuring tube 2 is flowed through the V-type point circular cone of V-type cone assembly 6, fluid little by little throttling is retracted to the inner edge wall of pipeline, according to the bernoulli principle as can be known, produce the pressure differential corresponding to the flow size before and after this V-type inner cone, this pressure differential is recorded by MEMS sensitive core body 4 and draws measuring tube 2 by signal wire 8.According to flow-differential pressure numerical relationship model and on-the-spot actual the demarcation, can realize dynamic and steady state measurement to flow.

Embodiment 3

As shown in Figure 3, the front end of V-type cone assembly 6 is fixedlyed connected with bracing frame 3 one ends, and bracing frame 3 other ends are fixed on measuring tube 2 inwalls; MEMS sensitive core body 4 is encapsulated in the V-type conical surface tube wall that is embedded in V-type cone assembly 6 in the encapsulating structure 5, and keeps sealing with tube wall; When the fluid in the measuring tube 2 is flowed through the V-type point circular cone of V-type cone assembly 6, fluid little by little throttling is retracted to the inner edge wall of pipeline, according to the bernoulli principle as can be known, produce the pressure differential corresponding to the flow size before and after this V-type inner cone, this pressure differential is recorded by MEMS sensitive core body 4 and draws measuring tube 2 by signal wire 8.According to flow-differential pressure numerical relationship model and on-the-spot actual the demarcation, can realize dynamic and steady state measurement to flow.

Claims (4)

1, a kind of V taper flow meter based on the MEMS sensor, it is characterized in that this device is made of MEMS sensitive core body (4), encapsulating structure (5), the signal wire (8) of flange (1), measuring tube (2), bracing frame (3), V-type cone assembly (6), negative pressure tappings (7), positive pressure tappings (9) and Sensor section; V-type cone assembly (6) is by coaxial measuring tube (2) inside that is fixed on of bracing frame (3); MEMS sensitive core body (4) is encapsulated in the encapsulating structure (5), places V-type cone assembly (6) inside or is embedded in V-type cone assembly (6) straight pipe wall or conical surface wall, and keep sealing; Positive pressure tappings (9) all is located on the V-type cone assembly (6) with negative pressure tappings (7), is positioned at measuring tube (2) inside; Two pressure pipes of MEMS sensitive core body (4) contact high pressure and low-pressure fluid by positive pressure tappings (9) with negative pressure tappings (7) respectively; Signal wire (8) with draw measuring tube (2) after MEMS sensitive core body (4) is connected.

2, a kind of V taper flow meter based on the MEMS sensor according to claim 1 is characterized in that, described MEMS sensitive core body (4) is the little pressure resistance type of silicon, piezoelectric type or capacitance type minitype pressure/pressure reduction sensitive core body.

3, a kind of V taper flow meter according to claim 1 based on the MEMS sensor, it is characterized in that, the front end of described V-type cone assembly (6) is fixedlyed connected with bracing frame (3) one ends, and bracing frame (3) other end is fixed on measuring tube (2) inwall.

4, a kind of V taper flow meter according to claim 1 based on the MEMS sensor, it is characterized in that, described encapsulating structure (5) upside is fixed on the V-type cone assembly inwall, downside communicates with positive pressure tappings (9) on the V-type cone assembly (6) and measures high pressure, the right side communicates with negative pressure tappings (7) and measures low pressure, and the left side is connected with signal wire (8).

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