CN100406855C - Device for the determination of flow parameters for a fluid and method for operating such a device - Google Patents
Device for the determination of flow parameters for a fluid and method for operating such a device Download PDFInfo
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- CN100406855C CN100406855C CN038238985A CN03823898A CN100406855C CN 100406855 C CN100406855 C CN 100406855C CN 038238985 A CN038238985 A CN 038238985A CN 03823898 A CN03823898 A CN 03823898A CN 100406855 C CN100406855 C CN 100406855C
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- pneumatic sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/696—Circuits therefor, e.g. constant-current flow meters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/696—Circuits therefor, e.g. constant-current flow meters
- G01F1/698—Feedback or rebalancing circuits, e.g. self heated constant temperature flowmeters
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/04—Monitoring of the detection circuits
- G08B29/043—Monitoring of the detection circuits of fire detection circuits
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
- G08B17/113—Constructional details
Abstract
The invention relates to a device for the determination of flow parameters of a fluid, in particular, the temperature and flow speed and changes therein, in a fluid flow for monitoring, a method for operating such a device, a determination method itself and a fire recognition or oxygen measuring device provided with such a device. The aim of the invention is the recognition of a slow or sudden blockage, crack or break in a pipe system (13) of an aspirative fire recognition device by means of a measurement technique, whereby an air flow sensor (1), operated with a constant excess temperature, is combined with a regulation algorithm, running in a microprocessor (4), for monitoring the fluid flow or the flow resistance in the pipe system (13). The required resistance of the air flow sensor (1) can thus be calculated according to an exact sensor calibration curve and a precise control loop (3) formed. The measured values recorded by the air flow sensor (1) are thus extremely reliable, such that changes in condition for the flow parameters provide information about the state of the pipe system (13) or the intake system.
Description
Technical field
The present invention relates to a kind of fluid stream to be monitored that is used for determining, the stream parameter in flue dust and gas pumping alarm particularly, temperature particularly, the device of flow velocity and variation thereof, it has the pneumatic sensor under the constant temperature mode operation of a thermoelectricity, a thermoelectric temperature sensor and a regulating circuit that is used to adjust the overtemperature Δ T on the pneumatic sensor the invention still further relates to a kind of method of moving described this device, a kind of method of work and a kind of fire/condition of a fire (Brand) recognition device or oxygen measurement device that is equipped with described kind of device that utilizes described device accordingly.
Background technology
Particularly by the device of the stream parameter described type of known beginning in the heater strip formula wind gage, definite and the correlation method that moves this device.Here the tinsel with heating places mobile fluid, according to the information of the heat acquisition of deriving from fluid about the various flows parameter.
There are two kinds of basic working methods for heater strip formula wind gage: constant current working method and constant temperature working method, in most of the cases use the constant temperature working method, because the degree of precision that particularly can avoid the thermal inertia of heater strip (probe) this moment and realize thus popping one's head in.
The basic thought of constant temperature working method is, reduces the influence of the thermal inertia of probe like this, promptly heater strip is remained on stationary temperature (resistance) all the time and heating current that will the be required for this reason scale as rate of flow of fluid.Usually use a Wheatstone bridge for this reason, thus by feedback make resistance remain a constant value and therefore the temperature of heater strip also remain constant.The thermal loss of popping one's head in thermal equilibrium necessarily equals electrical power supplied.At first be concerned about relation between rate of flow of fluid and the electric power from the angle of wind gage.This relation is extremely complicated, is non-linear, only by means of an experience and describe according to the rule (King) that given situation is revised respectively.Therefore when analyzing evaluation, must use a linearizer.
Fig. 1 has pointed out the basic circuit diagram of a constant temperature wind gage.A voltage definite, that provide by a servoamplifier 15 is provided on the vertical diagonal line C-D of electric bridge under equilibrium state.Convection current cooling if pop one's head on 18 changes, and then can produce a less voltage on horizontal diagonal line A-B, and described voltage feeds back on the vertical diagonal line C-D of electric bridge after several times of amplifications.The polarity of the voltage that wherein such selection is fed is so that electric bridge is realized self-equilibrating.
Except at rate of flow of fluid with as the complex relationship between the electric power of measured parameter detecting, also there is another problem, probe is to for example because the temperature variation of flow media or pressure change the variation of all heat radiations that may cause responds.Particularly when using continuously this method, when making reliable judgement with the state of the piping system that can flow therein to for example fluid according to the variation of tested flow parameter, this can throw into question.
Particularly in order in the fire recognition device of drawing-in type or oxygen measurement device, in sucker system, to monitor air-flow, importantly detect obstruction or pipe break in the sucker system reliably, so that can guarantee the errorless operation of fire recognition device or oxygen measurement device.Here the fire recognition device of drawing-in type is interpreted as such device, it initiatively aspirates the air of representational part amount through a piping system or channel system in a plurality of positions in space to be monitored, then the air of this part amount is supplied with a detecting device that is used for the detection of fires characteristic quantity or is used to detect air gas, particularly oxygen.
The fire recognition system of a drawing-in type mainly comprises ventilation blower and detecting device of a sucker system with several less SSs, one SS by sucker system extracting air sample in the object space, the fire characteristic amount in the air sample of next determining to be extracted in this detecting device.Because the fire recognition device of drawing-in type suction air sample and therefore initiatively aspirated the fire characteristic amount that may exist initiatively in the object space, so device is faster and sensitiveer than traditional solution to the reaction of the fire that taken place.Therefore best as far as possible intervention possibility is provided.
Conceptual understanding to the fire characteristic amount is a physical parameter; measurable change takes place in it in the environment of breaking out of fire, for example solid or liquid in environment temperature, the surrounding air or gas composition part (forming the flue dust of particulate or gasoloid/aerosol (Erosolen) or smog form) or environmental radiation.The fire recognition device of a drawing-in type is used all occasions that should detect extremely low almost undetectable fire characteristic amount especially, and is used in particular for the target monitoring or the space monitoring of for example electronic data processing (EDV) equipment or room server.
In the space of equipment therein to the responsive sealing of the influence reaction of water, such as EDV scope, switch room and switchgear building or have the parking space of the economic goods of higher-value, be used to the so-called inert rendering method that reduces fire hazard and stamp out a fire more and more.The fire extinguishing effect of Chan Shenging is based on oxygen and discharges principle in the method.As everyone knows, normal surrounding air by volume number percent by other gas composition of 21% oxygen, 78% nitrogen and 1%.For stamp out a fire and avoid fire by import the inert gas of discharging oxygen-such as pure nitrogen gas-raising in correlation space inert gas concentration and reduce the oxygen composition.If the oxygen composition drops to below the 15-18% percent by volume, many materials can not burn again.Depend on the combustible material that exists in the correlation space may require the oxygen composition by volume number percent for example further be reduced to 12%.
The inert gas installation that being used to like this implemented above-mentioned inert rendering method mainly has with lower member: an oxygen measurement device that is used to measure oxygen content in the object space to be monitored; The fire recognition device of a fire characteristic amount in space air that is used to detect object space; A control device that is used to analyze the data of oxygen measurement device and fire recognition device and is used for inert rendering method is carried out process control; The equipment that is used to make inert gas and inert gas is imported object space suddenly.
The oxygen measurement device is used to adjust the basic deactivation degree in the object space.If surpass a threshold value of oxygen concentration-for example because leakage-the control device in the object space sends an instruction to import inert gas in the space, to reduce the oxygen composition to a special equipment.If reach the threshold value of basic deactivation degree once more, then the oxygen measurement device sends signal.Wherein the situation of basic deactivation degree depends on spatial character.
In an advantageous applications, described drawing-in type fire recognition system and be used to avoid fire and/or the inert gas installation that stamps out a fire combined.The fire recognition device of oxygen measurement device and inert gas installation is integrated in the drawing-in type fire recognition system in this case.They are born to control device provides the monitoring objective space the required task from the data of the air sample that is extracted.
In order to guarantee the flawless as far as possible and maintenancefree operation mode as far as possible of drawing-in type device, necessary continuous monitoring is supplied with the volumetric flow rate of the air sample of detecting device.Volumetric flow rate depends on the mass rate and the density of the air sample of being supplied with, and density is again the function of air pressure and temperature.The monitoring that proves volumetric flow rate thus is a task complicated on measuring technique.In addition in order to confirm the obstruction or the damage of sucker system or SS reliably, for the higher measuring accuracy of volumetric flow rate monitoring requirement.This is particularly including in the measuring technique make-up air density that is used for volumetric flow rate monitoring or the influence of air pressure.
The present invention is based on such problem, promptly for the volumetric flow rate in the sucker system of monitoring drawing-in type fire recognition device, at present the measuring technique of using has very big unreliability, perhaps only to consider volumetric flow rate and does not consider resistance to flow about the reliable judgement of the state of sucker system in order to obtain.Therefore unreliability is unsuitable for uncompensated continuously use particularly because employed sensor depends on temperature and the air pressure or the fluid density of fluid stream.Reliably monitoring to volumetric flow rate in the sucker system also requires analysis to measure data as far as possible exactly.
This is external by having such problem in the known solution of prior art, can only analyze promptly that the long-time volumetric flow rate that continues changes in sucker system.Wherein should change with threshold value comparing usually, wherein report air-flow fault when surpassing described threshold value., selected bigger threshold value for fear of the fault alarm that produces owing to environmental impact (air pressure, temperature).Long tube has high resistance to flow, and near the pipe break the tube end only can cause less variations in flow like this.Use by prior art known devices and method and can not detect this less variations in flow.
Summary of the invention
The objective of the invention is according to described problem, improve like this beginning described type, that particularly in flue dust and gas pumping alarm, use, be used for the device that air-flow is monitored, can detect the stream parameter continuous and non-maintainingly, described detection is enough accurate, thereby can judge the state of sucker system reliably, and provide a kind of correlation method and corresponding work method of moving described device.
In the device of the described type of beginning, realize described purpose by a control algolithm of in a microprocessor, carrying out according to the present invention, this algorithm is included in the regulating circuit of this device, and makes the overtemperature Δ T on pneumatic sensor keep constant by described control algolithm.
Advantage of the present invention particularly in, described regulating circuit comprises a control algolithm of carrying out in a microprocessor, keep the overtemperature Δ T on pneumatic sensor constant by this control algolithm.Thus pneumatic sensor is adjusted at its working point or working temperature exactly, the fluctuation of described working point or working temperature and fluid temperature (F.T.) or variation are irrelevant.The heat that thermoelectric thus pneumatic sensor distributes is in fact only corresponding with the heat that is distributed by fluid.In this form of implementation, the flow through electric current of pneumatic sensor or advantageously in fact only represent the scale (Ma β) of stream parameter to be measured (speed, mass rate etc.) by the electric power that pneumatic sensor dissipates, and can not take place because the unreliability that the variation of fluid temperature (F.T.) causes.
Method by the described device of an operation realizes purpose of the present invention in addition, makes pneumatic sensor bring up to a temperature peak in short time in the method.
By in fluid to be monitored stream, particularly in flue dust and gas pumping alarm, determining the method for temperature T, flow velocity w and change in flow Δ w-of stream parameter-particularly, solve technical matters of the present invention according to the present invention by following method step: determine fluid temperature (F.T.) T in addition by means of a thermoelectric temperature sensor at one; According to fluid temperature (F.T.) T thermoelectricity and be operated in the overtemperature Δ T that sets on the pneumatic sensor under the constant temperature mode and be adjusted to a steady state value; Definite heat that distributes by thermoelectric pneumatic sensor; With according to the heat that is distributed by means of an analytical algorithm compute flow parameters of in a microprocessor, carrying out, particularly temperature, flow velocity, resistance to flow and variation thereof.
Advantage of the present invention particularly in, can realize a kind of very effective, be used for particularly the method determining the stream parameter at flue dust and gas pumping alarm, be used for optimizing the air-flow monitoring in piping system.Overtemperature Δ T on thermoelectric pneumatic sensor and fluid temperature (F.T.) T irrespectively have a steady state value, can realize especially thus, thermoelectric pneumatic sensor is operated in its pre-determined working point or working temperature exactly, and therefore the electric power reality that is dissipated only depends on fluid stream.Because the method according to this invention measuring error obviously reduces.In thermoelectric pneumatic sensor according to the present invention, by the wandering heat Q that sends out of fluid the scale of stream parameter to be determined by heating sensor.Because the overtemperature Δ T on the described sensor has a constant value, the heat Q that is distributed equals to supply with the heating power P of sensor.Heating power P depends on the heating current I according to equation (1):
P＝I
2·R (1)
Wherein R represents the internal resistance of sensor.The heat Q that distributes by sensor by the following description of equation (2):
Q＝[A+B·(ρ·V)
1/n]·(ΔT-T) (2)
Wherein A, B and n are the feature constants of sensor, before sensor brings into operation according to the experiment, that is to say by means of calibrating and determine described constant that ρ represents fluid density.From equation (1) and (2), draw, can determine the volumetric flow rate V and the mass rate (ρ V) of fluid stream by heating power P and temperature T.
From equation (1) and (2), draw, can determine the volumetric flow rate V and the mass rate N=ρ V of fluid stream by heating power P and temperature T.Resistance to flow F in pipe
wThe following flow velocity w that depends on:
F
w＝0.5·c·A·ρ·w
2 (3)
Because according to
V＝A·w (4)
Volumetric flow rate V depends on the cross-sectional area A of flow velocity w and pipe, for the resistance to flow F in pipe
wDraw:
F
w＝0.5·c·ρ·A
-1·V
2 (5)
From equation (5), draw, can determine resistance to flow F in the piping system by volumetric flow rate V
wWith its variation.
It is contemplated that in addition, detect the variation of the resistance to flow in the piping system based on described measured value.Require current measured value and initial measured value relatively for this reason, write down and store described initial measured value when for example bringing into operation in system.The method according to this invention is suitable for discerning the variation of the resistance to flow in the sucker system in addition.For this reason except also wanting the influence of make-up air density or fluid density ρ the volume flow measurement accurately, so that can judge resistance to flow reliably.According to the initial value of the pneumatic sensor of described storage and temperature sensor and according to current temperature with determine correction factor according to current absolute pressure by a table of setting up for this reason in some cases.This table is essential, because the different pumping power of different sucker systems and ventilator requires different correction factors.It is contemplated that, for example pick up current absolute pressure by the sensor that is designed for barometric surveying separately.Can certainly imagine other form of implementation at this.
Realize purpose of the present invention by a kind of like this fire recognition device of drawing-in type at last, described device is from space to be monitored or equipment continues to extract the space air sample or the apparatus cools air sample is also supplied with the detecting device that is used to discern the fire characteristic amount through piping system with described air sample, and this fire recognition device is equipped with foregoing, as to be used for determining a stream parameter device.
Utilization device according to the present invention provides the possibility of implementing foregoing method.
About determining that device provides advantageous modification of the present invention in dependent claims 2 to 5, in dependent claims 7, provide advantageous modification of the present invention about operation method, about determining that method provides advantageous modification of the present invention in dependent claims 9 and 10, in dependent claims 12 and 13, provide advantageous modification of the present invention about the fire recognition device and/or the oxygen measurement device of drawing-in type.
For described device imagination, described microprocessor comprises an analytical algorithm in addition like this, and described analytical algorithm is used for the electrical heating power P compute flow parameters according to pneumatic sensor, especially for mass rate N, flow velocity w and the temperature T of calculation of fluid flow.Advantage according to this form of implementation of the present invention is, can be in the described control algolithm of in microprocessor, carrying out according to the rated resistance of the thermoelectric pneumatic sensor of sensor characteristic curve calculation accurately, and can form accurate regulating circuit (for example pi regulator).Here for example can utilize A/D converter to measure the voltage on the thermoelectric temperature sensor and next described voltage is carried out filtering, to eliminate noise and other interference.Calculate the temperature T of fluid stream according to measured voltage
0Desirable constant overtemperature Δ T (for example 40 ℃) is added to fluid temperature (F.T.) T
0On.Its result is exactly the rated temperature T of thermoelectric pneumatic sensor
SollIn the analytical algorithm of microprocessor, determine the rated resistance of pneumatic sensor by described rated temperature according to the accurate sensor family curve.Regulator is regulated the voltage on the heater strip of pneumatic sensor, so that the actual value of the resistance of pneumatic sensor is adjusted to ratings.Keep overtemperature Δ T constant thus according to the present invention.By means of AD converter measure on the thermoelectric pneumatic sensor voltage or by the electric current of pneumatic sensor and next described voltage and current is carried out filtering.Calculate electrical power P by described voltage and current, this electric power is represented the scale of air-flow simultaneously.
Imagine in a particularly advantageous form of implementation according to device of the present invention, analytical algorithm comprises the identification that the rheologyization of the little sudden change formula of fluid flow, particularly volumetric flow rate change.For this reason except also wanting the influence of make-up air density the measurement volumes flow exactly, so that can judge resistance to flow thus.According to the initial value of pneumatic sensor of being stored and temperature sensor and according to Current Temperatures with can also prove the variation of the saltus step formula that airflow is less in some cases thus according to current air pressure.Here basic thought is, because the variation that interfering environmental impact (air pressure, temperature) causes is slower than the variation of pipe break usually.Thus the analysis of the variation of less saltus step formula is also made it possible to discern the unexpected obstruction of a unique SS, this for example can occur under situation about deliberately destroying, or appearance when carton is placed in SS front overhead.
Imagine in a particularly advantageous form of implementation, the variable density that depends on temperature and/or pressure that described analytical algorithm comprises fluid flow compensates.The advantage of this form of implementation particularly in owing to considered the variable density that depends on temperature or pressure of fluid stream, have nothing to do by of the fluctuation of the wandering electricity power of fluid with the variable density of fluid stream.Significantly improve the accuracy of stream parameter, the particularly resistance to flow determined by means of the present invention thus.
According to one of definite device of the present invention possible implementation imagination, described microprocessor comprises a storer that is used for the initial value of storage flow parameter.The advantage of this form of implementation is, not only can flow parameter with high precision computation in described analytical algorithm, and we can say the long-term state variation of free flow parameter.Because the calculating of stream parameter gradients is based on accurate air flow value, for example can advantageously measure the variation in the piping system of flue dust and gas pumping alarm in this form of implementation.For example may be owing to slowly or unexpected obstruction, crackle or break and such variation occurs.Owing to keep constant by the overtemperature Δ T of the present invention on pneumatic sensor, the gradient of gas stream parameter can occurrence temperature or the deviation that causes of alternate manner.Equally advantageously cancelled pneumatic sensor repeated balance/compensation.
Scheme in a possible realization advantageously is designed to pneumatic sensor, makes this sensor can bring up to a temperature peak in short time.This has such advantage especially, so pneumatic sensor is characterised in that the life-span that it is long especially.
Operation for so definite device preferably is designed to pneumatic sensor, this pneumatic sensor can be brought up in short time reach 500 ℃ temperature peak on one.Under the situation that temperature significantly improves, can remove the dirt that accumulates of pneumatic sensor thus especially effectively by the operation of short time.Use whole heating powers this moment, to burn or to remove the dirt particle that sticks on the pneumatic sensor.During this period of time advantageously close the ventilator of drawing-in type fire recognition device, to avoid any cooling to sensor.Utilize this cleaning to guarantee, even also can not accumulate on pneumatic sensor or the deposit dirt particle in using continuously, thereby the sensitivity of sensor is constant all the time.
A possible implementation of the present invention is, be used for determining that according to according to the present invention the device of stream parameter is integrated in a drawing-in type fire recognition device and/or the oxygen measurement device, described drawing-in type device from space to be monitored or equipment continues to extract the cooling air sample of space air sample or equipment and through piping system detecting device that is used to discern the fire characteristic amount of described sample supply.The advantage of this form of implementation particularly in, can monitor the air-flow in the piping system exactly and for example also can indicate reliably in piping system because slowly or unexpected obstruction, crackle or break and the variation that may occur.Thus can be especially the fire recognition device and/or the oxygen measurement device of reliable and Maintenance free ground use drawing-in type.
In another favourable form of implementation, imagine, particularly be integrated in the air inlet passage of detecting device of fire characteristic amount of the fire recognition device of a drawing-in type and/or oxygen measurement device at the middle part according to the pneumatic sensor of device of the present invention or temperature sensor.The advantage of this form of implementation is, whole electric devices of drawing-in type fire recognition device can be incorporated in the unit thus.Can know especially thus and construct described fire recognition device and/or oxygen measurement device simply.
Preferably imagine at last, pneumatic sensor is arranged in the position that narrows down according to the xsect in drawing-in type fire recognition device of the present invention and/or the oxygen measurement Device Testing device air inlet passage.Be in the position that flow velocity raises because xsect narrows down by this layout pneumatic sensor.Improved the dynamic property of pneumatic sensor thus equally.Therefore can detect the also minimum variation of analysis stream parameter.Therefore advantageously improve according to sensitivity of the present invention, that be used for the device of definite stream parameter.Can realize simultaneously optimization to the monitoring of drawing-in type fire recognition device and/or oxygen measurement device.Certainly also it is contemplated that other form of implementation at this.
Description of drawings
Describe the preferred embodiment of the present invention below with reference to the accompanying drawings in detail.
Wherein:
Fig. 1: according to the basic circuit diagram of the constant temperature wind gage of prior art;
Fig. 2: the block scheme that is used for determining the stream parameter according to a preferred embodiment according to device of the present invention;
Fig. 3: according to the synoptic diagram of a preferred embodiment of drawing-in type fire recognition device of the present invention;
Fig. 4 a: according to the longitudinal sectional view of the detecting device of the fire characteristic amount among the embodiment of Fig. 3; With
Fig. 4 b: according to the transverse sectional view of the detecting device of the fire characteristic amount among the embodiment of Fig. 3.
Embodiment
Fig. 1 illustrates a basic circuit diagram according to the constant temperature wind gage of prior art.The basic thought of constant temperature working method is, reduces the influence of the thermal inertia of heater strip probe 18 like this, promptly sensitive element 18 is remained on all the time on the stationary temperature (resistance), and heating current that will be required for this reason is as the scale of flow velocity.Use a Wheatstone bridge for this reason, wherein make the resistance of heater strip keep constant and therefore make the temperature of heater strip keep constant by feedback.A voltage definite, that provide by servoamplifier 15 is provided on the vertical diagonal line C-D of electric bridge under equilibrium state.If the cooling of the convection current on probe 18 changes, then on horizontal diagonal line A-B, produce a less voltage, this voltage is fed back on the vertical diagonal line C-D of electric bridge after amplifying several times.Here select the polarity of this feedback voltage like this, so that the electric bridge self-equilibrating.Relation between rate of flow of fluid and the wind gage voltage is non-linear at this moment, thereby must use a linearizer (Linearesator) in order further to analyze.After linearization, use a direct calibration curve, to obtain flow velocity by wind gage voltage.Probe 18 is all made a response to any variation of heat radiation usually in circuit shown in Figure 1.This also can be for example changed by the temperature of fluid or pressure and causes.Must consider this tittle in order accurately flow velocity to be measured also.In addition, shown in Fig. 1 according to the fluctuation of on the overtemperature of setting on the probe 18, not considering fluid temperature (F.T.) in the basic circuit diagram of the constant temperature wind gage of prior art.In order as far as possible accurately to measure, it is rational adjusting the constant temperature difference or overtemperature in probe 18.
Fig. 2 illustrates the block scheme according to device of the present invention that is used for determining the stream parameter according to a preferred embodiment.According to the pneumatic sensor that under constant temperature mode, moves 1 that the inventive system comprises a thermoelectricity and a temperature sensor 2.These two sensors are put into fluid to be measured.Realize the control of sensors 1,2 or read by a regulating circuit 3.This regulating circuit comprises a control algolithm of carrying out in a microprocessor 4, keep the overtemperature Δ T on the pneumatic sensor 1 constant by this algorithm.Therefore can calculate the rated resistance of thermoelectric pneumatic sensor 1 and form an accurate regulating circuit according to the accurate sensor family curve.The voltage U of for this reason at first utilizing an AD converter 5 to measure on the temperature sensor 2
0Next use a wave filter 6 to eliminate noise and other interference.In analytic unit 7, calculate air themperature T by described voltmeter
0Pre-determined constant overtemperature Δ T is added in air themperature T in further step
0On.The rated temperature T of consequently thermoelectric pneumatic sensor 1
SollThe rated resistance that described rated temperature calculating sensor 1 is arranged according to the accurate sensor family curve in microprocessor 4.Next the voltage on the regulating circuit 3 adjusting pneumatic sensors 1 is adjusted to the ratings of calculated in advance with the actual value with resistance.Keep the overtemperature Δ T on the pneumatic sensor 1 constant thus.
The voltage U of when detecting flow velocity, measuring on the thermoelectric pneumatic sensor 1 by means of an AD converter 5
1And electric current I
1, and next it is carried out filtering with a wave filter 6.In another analytic unit 7, calculate the electrical power P of pneumatic sensor 1 and the actual value of resistance by described electric current and voltmeter.Keeping the constant essential electric power of overtemperature Δ T is a scale of air-flow.
By shown in figure 2, be used for determining the embodiment according to device of the present invention of flow parameter also can measuring the stream parameter almost error freely, thereby also can compute flow parameters-particularly resistance to flow-state variation.For this reason a middle initial value of preserving flow parameter of storer (clearly not illustrating) that is integrated in the microprocessor 4.Utilize the gradient of analytical algorithm convection current parameter to calculate continuously then.Therefore utilize this form of implementation can test example as because the variation in slow or unexpected obstruction, the crackle of runner or the fluid stream that produces that breaks.
Changing owing to temperature and/or air pressure when causing that atmospheric density changes, even piping system does not change, the volumetric flow rate of the fluid that is detected equally also can change.In microprocessor 4, carry out essential thus compensation to air density change.Determine compensation factor according to initial value (temperature, air-flow) and Current Temperatures.Adopt an absolute air pressure probe to measure air pressure (clearly not illustrating) alternatively.
Fig. 3 shows the synoptic diagram according to the preferred implementing form of drawing-in type fire recognition device of the present invention or oxygen measurement device.In object space 12, arrange a sucker system 13 that is used for through different SS suction air samples.This sucker system 13 is equipped with a suction alarm, is supplied to one from the air sample of object space 12 and is used to discern the fire characteristic amount or is used to measure oxygen and the detecting device 8 of other gas in this alarm.Be provided with a ventilator 14 in addition, this ventilator is used for the air sample through piping system suction object space.Here the pumping power of ventilator 14 and affiliated sucker system are complementary.For the non-fault ground work of drawing-in type fire recognition device shown in can guaranteeing or oxygen measurement device, must continuous monitoring supply with fault in the air-flow of detecting devices 8 and the identification suction in time through sucker system 13.Be used for determining that according to of the present invention the device of stream parameter is positioned at the suction alarm of drawing-in type fire recognition device or oxygen measurement device for this reason.
Fig. 4 a and Fig. 4 b illustrate according to the fire characteristic amount that is used for of the embodiment of Fig. 3 or are used for the longitudinal sectional view or the transverse sectional view of the detecting device 8 of gas.The subdivision line dots in Fig. 4 a.Shown in detecting device in thermoelectric pneumatic sensor or temperature sensor 1,2 be integrated in the flue dust and/or gas measurement unit (Messzelle) of suction alarm.Described two sensors 1,2 are positioned at the middle part of air inlet passage.Xsect narrows down on the height of pneumatic sensor 1, thereby flow velocity improves.Improve the dynamic property of pneumatic sensor 1 thus.
In an improvement project of the present invention, pneumatic sensor 1 is significantly improving the operation removing dirt that passes through the short time under the situation of temperature.During this period of time close ventilation blower 14, to avoid any cooling effect.Use whole heating powers, to burn or to remove the dirt particle that sticks on the strength sensor 1.During this period of time do not carry out airflow analysis.Perhaps automatically or manually control at regular intervals and carry out this cleaning.Realize by described cleaning, even under the situation of long period operation, also can reduce the sensitivity of pneumatic sensor owing to accumulating of dirt particle.
The reference number of element
1 pneumatic sensor, 2 temperature sensors
3 regulating circuits, 4 microprocessors
7 analytic units, 8 detectors
9 air inlet passage, 10 gas sensors or smoke gas sensor
11 gas sensors or smoke gas sensor 12 object spaces
13 sucker systems, 14 ventilator
15 servoamplifiers, 16 resistance
17 pots, 18 heater strips probe
19 voltage sources
The physical quantity label
P electric power I sensor heating current
U sensor voltage R sensor resistance
V volumetric flow rate w flow velocity
F
wResistance to flow c resistance coefficient
ρ fluid density N mass rate
The heat that T fluid temperature (F.T.) Q distributes
The cross-sectional area of A pipe
Claims (14)
1. be used for determining the device of stream parameter, the pneumatic sensor that under constant temperature mode, moves (1) with a thermoelectricity, the temperature sensor of a thermoelectricity (2) and a regulating circuit (3) that is used to adjust the overtemperature Δ T on the described pneumatic sensor (1), described regulating circuit (3) comprises a control algolithm of carrying out in a microprocessor (4), keep the overtemperature Δ T on the described pneumatic sensor (1) constant by this algorithm, it is characterized in that, described microprocessor (4) comprises a storer that is used for storage flow parameter initial value, in analytical algorithm, to be used for the long-term state variation of compute flow parameters, wherein, carry out the calculating of state variation according to stream parameter initial value and current measured value.
2. according to the device of claim 1, it is characterized in that described microprocessor (4) also comprises an analytical algorithm that is used for according to the electrical heating power P compute flow parameters of pneumatic sensor (1).
3. according to the device of claim 1 or 2, it is characterized in that described analytical algorithm comprises that the variable density relevant with temperature and/or pressure of fluid flow compensates.
4. according to the device of claim 1 or 2, it is characterized in that described analytical algorithm comprises the mobile variation of the less sudden change formula of identification fluid stream.
5. operation is characterized in that according to the method for the device of claim 1 or 2, and described pneumatic sensor (1) is brought up to a temperature peak in short time.
6. according to the method for claim 5, it is characterized in that described temperature peak is 500 ℃.
7. be used for determining the method for stream parameter, have following method step:
A) determine fluid temperature (F.T.) T by means of a thermoelectric temperature sensor (2);
B) be adjusted in the thermoelectric pneumatic sensor (1) that moves under the constant temperature mode according to described fluid temperature (F.T.) T and go up the constant overtemperature Δ T that sets;
C) definite heat Q that distributes by described thermoelectric pneumatic sensor (1); With
D) according to the analytical algorithm compute flow parameters of the heat Q that is distributed by means of an execution in a microprocessor (4),
It is characterized in that, calculate long-term state variation according to stream parameter initial value and current measured value.
8. according to the method for claim 7, it is characterized in that, at method step d) have following other method step afterwards:
E) at method step d) in the stream parameter determined, the fluid density relevant with temperature and/or pressure changed compensating.
9. according to the method for claim 7 or 8, it is characterized in that having following other method step:
F) determine stream parameter variation in time definite in step d).
10. drawing-in type fire recognition device, described device is from a space or the lasting detecting device (8) that extracts the cooling air sample of space air sample or equipment and through a piping system (13) described air sample supply one is used to discern fire characteristic amount and/or airborne gas of equipment (12) to be monitored, it is characterized in that, be provided with a device according to one of claim 1 to 4 constant current parameter really.
11. the drawing-in type fire recognition device according to claim 10 is characterized in that, described pneumatic sensor (1) and/or temperature sensor (2) are integrated in the detecting device (8).
12. the drawing-in type fire recognition device according to claim 11 is characterized in that, described pneumatic sensor (1) and/or temperature sensor (2) are integrated in the middle part of the air inlet passage (9) of detecting device (8).
13., it is characterized in that described pneumatic sensor (1) is arranged in the air inlet passage (9) of detecting device (8) on the position that an xsect narrows down according to each drawing-in type fire recognition device in the claim 10 to 12.
14. drawing-in type oxygen measurement device, described device is from a space or the lasting detecting device (8) that extracts the cooling air sample of space air sample or equipment and described air sample supply one is used for airborne gas through a piping system (13) of equipment (12) to be monitored, it is characterized in that, be provided with a device according to one of claim 1 to 4 constant current parameter really.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10246747 | 2002-10-07 | ||
| DE10246747.1 | 2002-10-07 | ||
| DE10251891.2 | 2002-11-07 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1688872A CN1688872A (en) | 2005-10-26 |
| CN100406855C true CN100406855C (en) | 2008-07-30 |
Family
ID=32038296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN038238985A Expired - Fee Related CN100406855C (en) | 2002-10-07 | 2003-08-28 | Device for the determination of flow parameters for a fluid and method for operating such a device |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN100406855C (en) |
| DE (1) | DE10251891B4 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1768074A1 (en) * | 2005-09-21 | 2007-03-28 | Siemens Schweiz AG | Early detection of fires |
| US8306884B2 (en) * | 2009-12-09 | 2012-11-06 | Air Liquide Industrial U.S. Lp | Management of volumetric product delivery |
| ES2394872T3 (en) | 2010-07-15 | 2013-02-06 | Siemens Schweiz Ag | Detection of obstructions and interruptions of an aspirated smoke detector (ASD) |
| CN102182929B (en) * | 2010-12-10 | 2013-02-20 | 聚光科技(杭州)股份有限公司 | Device and method for detecting pipeline blockage |
| DE102012213692A1 (en) | 2012-08-02 | 2014-02-06 | BSH Bosch und Siemens Hausgeräte GmbH | Vapor extraction device and method for controlling a fan motor of a fan and for air cleaning effect determination |
| DE102013021305B3 (en) | 2013-12-19 | 2014-10-30 | Krohne Messtechnik Gmbh | Circuit arrangement for temperature monitoring and calorimetric mass flowmeter |
| CN109862933B (en) * | 2016-09-16 | 2022-03-18 | 菲舍尔和佩克尔保健有限公司 | Thermistor flow sensor with multiple temperature points |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87206900U (en) * | 1987-04-29 | 1988-01-13 | 北京工业大学 | Self-adapting flowmeter |
| US5247156A (en) * | 1990-11-13 | 1993-09-21 | Cableries Et Trefileries De Cossonay S.A. | Apparatus for measuring physical properties of fluids |
| WO1997030427A1 (en) * | 1996-02-15 | 1997-08-21 | Wagner Alarm- Und Sicherungssysteme Gmbh | Method and device for detecting incipient fires |
| CN2453395Y (en) * | 2000-11-30 | 2001-10-10 | 冶金工业部马鞍山矿山研究院 | Wind flow parameter measuirng instrument |
| US6450024B1 (en) * | 2001-03-07 | 2002-09-17 | Delta M Corporation | Flow sensing device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63252223A (en) * | 1987-04-09 | 1988-10-19 | Mazda Motor Corp | Fuel control apparatus |
| GB8903744D0 (en) * | 1989-02-18 | 1989-04-05 | Endress & Hauser Ltd | Flowmeter |
| DE4407209C2 (en) * | 1994-03-04 | 1996-10-17 | Bosch Gmbh Robert | Device for measuring the mass of a medium flowing in a line |
| DE19924400C1 (en) * | 1999-05-27 | 2001-01-25 | Securiton Ag | Fire detectors and fire detection methods |
-
2002
- 2002-11-07 DE DE10251891A patent/DE10251891B4/en not_active Expired - Fee Related
-
2003
- 2003-08-28 CN CN038238985A patent/CN100406855C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87206900U (en) * | 1987-04-29 | 1988-01-13 | 北京工业大学 | Self-adapting flowmeter |
| US5247156A (en) * | 1990-11-13 | 1993-09-21 | Cableries Et Trefileries De Cossonay S.A. | Apparatus for measuring physical properties of fluids |
| WO1997030427A1 (en) * | 1996-02-15 | 1997-08-21 | Wagner Alarm- Und Sicherungssysteme Gmbh | Method and device for detecting incipient fires |
| CN2453395Y (en) * | 2000-11-30 | 2001-10-10 | 冶金工业部马鞍山矿山研究院 | Wind flow parameter measuirng instrument |
| US6450024B1 (en) * | 2001-03-07 | 2002-09-17 | Delta M Corporation | Flow sensing device |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10251891B4 (en) | 2007-07-26 |
| CN1688872A (en) | 2005-10-26 |
| DE10251891A1 (en) | 2004-04-22 |
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