阅读说明：本技术 改进冷却装置的火焰检测器 (Flame detector with improved cooling device ) 是由 杨煜 郑植 温新叶 吴明光 于 2020-12-11 设计创作，主要内容包括：本发明公开一种改进冷却装置的火焰检测器。火焰检测器由火检探头、信号外理和通信模块、电缆组件,配置LoRa无线模块的热式气体质量流量计组成；火检探头包括光学镜头组、光导纤维、光敏元件、内/外导管、自清洁出风环。外导管上布置微孔,冷却风一分为二；一路经外导管微孔、在其外表上形成气膜冷却,使双层冷却的冷却潜能充分发挥：文丘里出风口的风道设计使冷却风从镜头前面四周出风,出风导向镜片中心,提高镜片冷却效果,具备自洁功能；采用热式气体质量流量计检测冷却风的流量和温度,建立冷量与流量、温度的单值函数,排除了冷却风道堵塞隐患；增设LoRa无线冗余信道,上传冷却风的流量和温度数据,以及火焰信息,提高了电缆有线信道的可靠性。(The invention discloses a flame detector with an improved cooling device. The flame detector consists of a fire detection probe, a signal external and communication module, a cable assembly and a thermal gas mass flowmeter with a LoRa wireless module; the fire detection probe comprises an optical lens group, a light guide fiber, a photosensitive element, an inner conduit, an outer conduit and a self-cleaning air outlet ring. Micropores are arranged on the outer conduit, and the cooling air is divided into two parts; one path of air film cooling is formed on the outer surface of the outer conduit through the micropores of the outer conduit, so that the cooling potential of double-layer cooling is fully exerted: the air duct design of the Venturi air outlet enables cooling air to be exhausted from the periphery of the front of the lens, the exhausted air is guided to the center of the lens, the cooling effect of the lens is improved, and the lens has a self-cleaning function; the flow and the temperature of cooling air are detected by adopting a thermal gas mass flow meter, a single-value function of the cooling capacity, the flow and the temperature is established, and the hidden danger of the blockage of a cooling air channel is eliminated; add the wireless redundant channel of loRa, upload the flow and the temperature data of cooling air to and flame information, improved the wired channel's of cable reliability.)

1. A flame detector with an improved cooling device is characterized in that the flame detector consists of a fire detection probe (10), a signal processing and communication module (20), a cable assembly (30) and a thermal gas mass flowmeter (40) provided with a LoRa wireless module, wherein the fire detection probe (10) comprises an optical lens group (11), a light-guide fiber (12), a photosensitive element (13), an inner conduit (14), an outer conduit (15) and a self-cleaning air outlet ring (18); the inner conduit (14) is concentric with the outer conduit (15), the optical fiber (12) is positioned on the central axis of the inner conduit (14), the inner conduit (14) is embedded in the outer conduit (15), an aluminum film (16) is sprayed on the outer side of the outer conduit (15), micropores (17) are arranged on the outer conduit (15), the density of the distribution from the front end of the fire detection probe (10) to the outer wall of the furnace wall and the micropores (17) is dense → sparse → dense, and the optical lens group (11) and the self-cleaning air outlet ring (18) are positioned at the front end of the fire detection probe (10); an air outlet of the self-cleaning air outlet ring (18) adopts a Venturi air channel structure, a Venturi throat diffusion section is parallel to the lens, high-speed low-pressure cooling air is exhausted from the periphery in front of the lens, and the exhausted air is guided to the center of the lens;

the optical lens group (11) is connected to the photosensitive element (13) through the optical fiber (12), the photosensitive element (13) is connected with the signal management and communication module (20), and the signal management and communication module (20) is connected with the DCS through the cable assembly (30); the optical lens group (11) focuses light emitted by target flame, a focused light signal is transmitted to the photosensitive element (13) through the optical fiber (12), electrical parameters of the photosensitive element (13) are related to the light of the target flame, and the signal processing and communication module (20) collects electrical parameter values of the photosensitive element (13), acquires characteristic values of the light of the target flame and uploads the characteristic values to the DCS through a cable wired channel; the thermal gas mass flow meter (40) provided with the LoRa wireless module is arranged at a cooling air inlet and connected with the signal processing and communication module (20), the flow and the temperature of cooling air are detected, the characteristic value of target flame light is read from the signal processing and communication module (20) and is uploaded to the DCS through the LoRa wireless channel, and the LoRa wireless module is additionally arranged on the DCS;

the cooling air is input from a cooling air inlet of the flame detector and divided into two paths: one path of the air flows to a self-cleaning air outlet ring (18) through an inner conduit (14); 20-40% of the other path of cooling air passes through the micropores (17), forms an air film on the outer surface of the outer guide pipe for cooling, and is finally discharged to the hearth, and the rest 80-60% of the cooling air in the other path passes through the outer guide pipe (15) to the self-cleaning air outlet ring (18); the self-cleaning air outlet ring (18) collects cooling air flowing in from the inner guide pipe (14) and residual cooling air flowing in from the outer guide pipe (15), and air outlet formed by collecting two strands of cooling air is guided to the center of the lens to cool the lens and finally discharged to a hearth.

2. The flame detector of the improved cooling device of claim 1, wherein the thermal gas mass flow meter (40) equipped with the LoRa wireless module comprises a temperature sensor constant current source module (100), a temperature sensor module (200), a temperature sensor signal conditioning module (300), a speed sensor PWM driving module (400), a speed sensor module (500), a speed sensor signal conditioning module (600), a signal processing and main control module (700), an annular flow equalizing plate (800) and a LoRa wireless communication module (900), wherein the signal processing and main control module (700) takes an STM32F103 chip as a core, and the LoRa wireless communication module (900) is E32-TTL-100; under the action of the temperature sensor constant current source module (100), the compensation resistor R of the temperature sensor module (200)_LPrecision resistor Rb output voltage V_LAnd Vb_LVoltage V of_LAnd Vb_LThe signals are output to a signal processing and main control module (700) through a temperature sensor signal conditioning module (300); the speed resistance R of the speed sensor module (500) is driven by the speed sensor PWM driving module (400)_HPrecision resistor Ra output voltage V_HAnd Va_HVoltage V of_HAnd Va_HThe signals are output to a signal processing and main control module (700) through a speed sensor signal conditioning module (600); STM32F103 pins 10, 11, 12, 13 and 14 of the signal processing and main control module (700) are respectively connected with E32-TTL-100 pins 1, 2, 3, 4 and 5, and pins 6 and 7 of E32-TTL-100 are respectively connected with VCC and ground; STM32F103 pins 21 and 22 of the signal processing and main control module (700) are accessed to USART ports of the signal processing and communication module (20);

the signal processing and master control module (700) is based on the voltage V_L，V_H、Va_HCalculating the compensation resistance R_LResistance value, speed resistance R_HResistance value, temperature of temperature sensorT_LTemperature T of speed sensor_HAnd according to T_HL＝T_H－T_L0≈T_H－T_LBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, a PWM control signal is generated, the output of a PWM driving module (400) of the speed sensor is adjusted, and T is the constant temperature difference requirement_L0Is the temperature of the gas to be measured; calculating the mass flow q according to the formula (1)_m；

The theoretical model of a thermal gas mass flowmeter is shown as follows:

in the formula, q_mIs the mass flow rate; i is_HHeating current for speed sensor, R_HIs the resistance of the speed sensor, T_HIs the temperature of the speed sensor; t is_L0Is the temperature of the gas to be measured, T_LT is used in engineering for the measured gas temperature measured by a flowmeter temperature sensor (not shown in the formula)_LApproximate T_L0(ii) a A. B is an empirical constant;

an annular flow equalizing plate (800) is arranged on a pipeline of the gas to be measured, the gas to be measured is rectified by the annular flow equalizing plate (800), so that the speed of each point of the gas flow on the axial section of the pipeline is uniformly distributed, and a measuring rod of a flowmeter is positioned behind the annular flow equalizing plate (800); two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor R_LMeasuring hole at the bottom of measuring rod, speed resistor R_HThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor R_LAnd a velocity resistance R_HHeat conduction of (2).

3. The thermal gas mass flowmeter (40) with LoRa wireless module according to claim 2, wherein the circuit of the temperature sensor module (200) comprises a precision resistor Rb and a compensation resistor R connected in series_L(ii) a The other end of the precision resistor Rb and the terminal Point_IS、Point_Vb_L1 connected to output voltage Vb_LThe output of the temperature sensor constant current source module (100) IS connected with a terminal Point _ IS; compensation resistor R_LThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connected_LAnd the series Point of (1) and the terminal Point _ V_L1 connected to each other, output voltage V_L(ii) a The circuit of the speed sensor module (500) comprises a precision resistor Ra and a speed resistor R which are connected in series_H(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ Va_H1 connected to output voltage Va_HThe output of the speed sensor PWM driver module (400) is connected to the terminal Point _ PWM 2; velocity resistor R_HThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connected_HAnd the series Point of (1) and the terminal Point _ V_H1 connected to each other, output voltage V_H(ii) a Compensation resistor R_LAnd a velocity resistance R_HThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference T_HL＝T_H－T_L0The temperature was set at 100 ℃.

4. A flame detector operation and maintenance method using the improved cooling device as claimed in claim 1, wherein the flame detector operation and maintenance method flow comprises an off-line flow of the flame detector, an on-line flow of the flame detector;

the variables are described as follows:

temperature, t

Flow rate, f

Upper limit of upper limit, UL

Lower limit, LL

Upper temperature limit T _ UL

A lower flow limit F _ LL;

off-line flow of flame detector to improve cooling device:

given that the upper limit of the cooling air temperature T _ UL is 150 ℃, and the lower limit of the cooling air flow F _ LL is 0.5m³/S

Secondly, setting a cooling air qualified temperature-flow cold quantity table, wherein Ti is an integer, i is more than or equal to 1 and less than or equal to N, and N is more than or equal to 1

Temperature of T1＝-10 …… TN＝150 Flow rate m³/S ≥0.5 ≥…… ≥1.5

Improving the on-line flow of the flame detector of the cooling device:

firstly, detecting the temperature t of cooling air

If T is more than T _ UL, the cooling air over-temperature alarm is carried out, and then

② detecting the flow f of cooling air

If F is less than F _ LL, the cooling air ultra-low flow rate alarm is carried out, and then

Checking the qualified temperature-flow cold quantity meter of cooling air, Fi corresponding to Ti

If f is less than Fi, the low flow of cooling air is alarmed, then

Reading, flame detector signal processing and communication module (20) flame characteristic value + t + f

Uploading the DCS through the LoRa wireless communication module (900)

And fifthly, returning to the step I.

Note: INT (t +0.5) performs the cooling wind temperature t, rounded.

Technical Field

The present invention belongs to the field of flame detector technology. In particular to a flame detector which adopts a vacuum aluminum-plated film, an inner and outer conduit double layer and air film cooling technology to detect the temperature and flow parameters of cooling air and upload working condition data through LoRa.

Background

In 2018, the generated energy composition proportion and the on-line electricity price of various energy sources in China are as follows: 73.32% of thermal power, 0.37% of power, 16.24% of hydropower, 0.28% of power, 4.33% of nuclear power, 0.31% of power, 4.29% of wind power, 0.39% of power, 1.32% of photovoltaic power and 0.35% of power. With the continuous production of new energy, the load peak-valley difference of the power grid is increased, and the peak regulation is difficult. Peak shaving in the traditional sense is to adjust the peak value of the power grid; the peak regulation is more mean to lower the valley value of the power grid, so as to make up a digestion space for new energy sources such as wind, light, tide and the like.

The first three-door nuclear power station of the third generation in China does not have the nuclear power privilege of the power industry on the basis of load operation; planning and clearly showing that nuclear power participates in power grid valley peak regulation: 90% of the early part of the life runs according to the formula of '15-1-7-1' (15h base charge, 1h down-regulation to 50% base charge, 7h 50% base charge, 1h up-regulation back-charge). The sustainable development of energy production and consumption depends on the development of renewable low-carbon energy at the supply side, and overcomes the inherent defects of intermittence, randomness, uncontrollable property and the like of the renewable low-carbon energy. The resource of China 'rich coal, poor oil and little gas' is determined to be a power generation mode mainly based on coal in a foreseeable time. The coal-fired generating set in China is also used as a peak shaving unit, so that the load and the combustion of the coal-fired generating set are adjusted frequently; in recent years, the output valley value of the coal-fired unit goes down all the way: 50% → 40% → 30% base charge, approaching even the unimaginable 25% base charge; on the other hand, most of the fire coal of the thermal power generating unit is mixed coal, and the coal quality is complex, so that the flame of a hearth of the coal-fired boiler often deviates from the preset working condition.

Now, take a coal-fired boiler of a unit 2X 650MW + 2X 600MW from zhejiang X power generation company, X group as an example. A critical Bunsen direct-flow boiler with the model HG-1890/25.4-YM4 is adopted: single hearth, single intermediate reheating and sliding pressure operation; the front wall and the rear wall are oppositely combusted, 15 axial swirl combustors (LNASB) are respectively arranged on the front wall and the rear wall, three layers are symmetrically arranged, and each layer is 5 axial swirl combustors; the LNASB at the bottom layer of the front wall is provided with a plasma ignition device for supporting combustion and stabilizing combustion, and the other layers are provided with an oil gun for supporting combustion and stabilizing combustion; each LNASB is provided with 30 coal-fired flame detectors, and 25 fuel-fired flame detectors are additionally arranged for the LNASB for supporting combustion and stabilizing combustion of an oil gun; the 55 flame detectors are all cooled by air, and the cooling air comes from two special cooling fans which are backup to each other. And 2 layers of over-fire air ports are respectively arranged on the front wall and the rear wall above the upper-layer pulverized coal burner, 5 over-fire air ports are arranged on each layer, and the total number of the over-fire air ports is 20.

A boiler Furnace safety monitoring system (FSSS) is an important component for ensuring the safety of a coal-fired boiler Furnace, and a flame detector is a core component of the FSSS; when the burner is not fired, the flame detector stops the supply of fuel in time, and the accident caused by fuel accumulation is avoided. In 1993, in 3 months, the YYY power plant boiler in the area of the company X exploded and crashed 40 people suffered from accidents and the flame detector of the FSSS is knocked to sound an alarm clock. At present, most of power plant boilers are provided with flame detectors of FORNEY, COEN and ABB companies. Flame measurement is divided into four categories, namely flame acoustics, thermal characteristic detection, photoelectric characteristic detection and image processing according to mechanisms. The first two types are easily interfered by other sound sources and heat sources of a boiler, the requirements of large-scale power generation equipment on safe operation are difficult to meet, and the fourth type has overhigh cost, so that a flame detector based on photoelectric characteristics is used for online operation of a large-scale coal-fired unit in the power industry. The flame detector consists of a fire detection probe, a cable, a signal processing and communication module, wherein the fire detection probe comprises an optical lens group (a flat mirror and a flat convex mirror), an optical fiber and a photosensitive element (a photosensitive resistor, a silicon photocell and a photodiode). The optical lens group is positioned at the front end of the fire detection probe, focuses the flame light of the target, and transmits the focused light signal to the photosensitive element through the optical fiber.

The operation and maintenance big data of the power generation companies of Zhejiang X of the X group, other power generation companies subordinate to the X group and the power generation companies in the same industry are mined; the carding analysis operation and maintenance data shows that: the short plate of FSSS reliability is the flame detector; further statistical analysis showed that: in the failure summary list of each unit of the flame detector, the failure points of the first and second bit columns are the fire detection probe and the cable, the working life of the two is far lower than the design life, and the two are two short plates in the FSSS reliability. The origin tracing short plate has both external and internal causes. For the external reasons: the thermal power generating unit undertakes peak/valley bidirectional peak regulation of the power grid and adopts fire coal of mixed coal; it is impossible to give up or reduce the bidirectional peak shaving, and on the contrary, the bidirectional peak shaving workload is only increased day by day; secondly, the operation economy is the first requirement of the power plant, the mixed coal is an important gripper for realizing the first requirement, and the history of using single coal mine fire coal in the whole life cycle of the power plant is already daylily in the Mingri day; therefore, it is not feasible to shorten the board by eliminating "external causes". The inherent reasons are: the problem of cooling of flame detectors, a long-standing problem in the industry; the industry has made great progress through diligent efforts, so that the problems still exist after being shocked; therefore, it is necessary to examine the cooling problem of the flame detector again, and from the standpoint of the cooling result of the flame detector in the industry, the flame detector with the improved cooling device is proposed to overcome the shortcomings of the existing solutions: the method fills the neglected cooling link, excavates the cooling potential of the existing cooling technology, perfects the detection scheme of the cooling air parameters, and explores the possibility of adding a wireless redundant channel on the basis of a cable and wired channel.

1. The heat generated when the boiler operates heats the fire detection probe through two modes of heat conduction and heat radiation, the existing cooling scheme focuses on the heat conduction, but neglects the negative effect of the heat radiation on the fire detection probe; the improved strategy is to adopt a vacuum aluminizing process to spray an aluminum film on the outer conduit of the fire detection probe so as to reduce the radiant heat.

2. The existing solution of the cooling air duct of the fire detection probe is a double-layer cooling technology of an inner conduit and an outer conduit, wherein the double-layer cooling technology is an improvement on the original single-layer cooling technology, so that the double-layer cooling technology has a better cooling effect, but still has the potential which is not utilized. The improved strategy is to exploit the cooling potential of the double-layer cooling technology: by using the air film cooling technology of the turbine blade, micropores are arranged on the outer guide pipe, and the cooling air flow is divided into two parts; one path is discharged to a hearth from the front of the lens group, and the other path forms an air film on the outer surface of the outer guide pipe through the micropores on the outer guide pipe for cooling and is finally discharged to the hearth; in addition, the design of the optimized air duct enables cooling air to be discharged from the periphery of the front part of the lens, and the discharged air is guided to the center of the lens, so that the cooling effect of the lens is improved, and the lens has a self-cleaning function.

3. The existing solution of the fire detection probe for detecting the cooling air parameter is to detect the air pressure at an inlet, and has the advantages of simplicity and the defects that the cold quantity is not a single-value function of the air pressure, and the indirect detection method cannot eliminate the hidden trouble of the blockage of the cooling air channel. The improved coping strategy is to adopt a thermal gas mass flowmeter, detect the flow and the temperature of a cooling air inlet, establish a single-value binary function of the cooling capacity, the flow and the temperature, and eliminate the hidden trouble of the blockage of a cooling air channel.

4. Flame information collected by the flame detector is uploaded to the DCS through a cable wired channel, dozens of cables are laid close to the furnace wall, the flame information collected by the flame detector is uploaded through a cable bridge after being collected, and the failure rate is high. The improved strategy of coping is to add the wireless redundant channel of loRa, and loRa not only uploads the flow and temperature data of heat transfer type gas mass flow meter, uploads flame information moreover, improves the reliability of the wired channel of cable.

A review of the more representative intellectual property efforts of flame detectors follows:

the invention relates to a flame detector probe (ZL2008101807012), which provides that a quartz glass sheet is arranged between a photoelectric tube protective sleeve cover and a photoelectric tube protective sleeve, and an annular gap is formed between the quartz glass sheet and the photoelectric tube protective sleeve; through the design of the cooling air duct and the quartz glass sheet, the service life of the product is prolonged.

The invention discloses an adjustable visual field type fire detection probe (application No. 2012101235895), which comprises a fire detection lens, an outer tube/inner tube, an optical fiber, a fire detection processor, a fastening nut, a sealing element and an O-shaped gasket, wherein the surface of the tail end of the outer tube is carved with threads, the inner part of the outer tube is provided with a slope, the fastening nut is sleeved at the tail end of the inner tube and is meshed with the threads at the tail end of the outer tube, and the sealing element is conical and has the same angle with the slope at the inner side of the outer tube.

The invention relates to a flame detector cooling device and a flame detector cooling method (application No. 2017101956798), and the cooling device comprises a flame detector probe, a flame detector probe cooling air blowing opening, an outer cooling pipe, an optical fiber and an inner cooling pipe. The flame detector probe is arranged in the outer cooling pipe; the inner cooling pipe sleeve is arranged in the outer cooling pipe; the optical fiber is arranged in the inner cooling tube; the optical fiber protective sleeve is changed from a single-layer cooling air channel into a double-layer cooling air channel, so that the problems that the optical fiber is easy to damage, a flame detection probe is easy to block ash and the like are solved.

The exploration of the related intellectual property has reference value, but the achievement still has limitation; further innovative designs are necessary.

Disclosure of Invention

It is an object of the present invention to overcome the disadvantages of the prior art and to provide a flame detector with an improved cooling arrangement.

The flame detector of the improved cooling device consists of a fire detection probe, a signal external management and communication module, a cable assembly and a thermal gas mass flowmeter with a LoRa wireless module, wherein the fire detection probe comprises an optical lens group, a light-guide fiber, a photosensitive element, an inner conduit, an outer conduit and a self-cleaning air outlet ring; the inner conduit and the outer conduit are concentric, the optical fiber is positioned on the central axis of the inner conduit, the inner conduit is embedded in the outer conduit, the aluminum film is sprayed on the outer side of the outer conduit, micropores are arranged on the outer conduit, the density of the distribution of the micropores from the front end of the fire detection probe to the outer wall of the furnace wall is dense → sparse → dense, and the optical lens group and the self-cleaning air outlet ring are positioned at the front end of the fire detection probe; an air outlet of the self-cleaning air outlet ring adopts a Venturi air channel structure, a Venturi throat diffusion section is parallel to the lens, high-speed low-pressure cooling air is exhausted from the periphery in front of the lens, and the exhausted air is guided to the center of the lens;

the optical lens group is connected with the photosensitive element through the optical fiber, the photosensitive element is connected with the signal appearance and communication module, and the signal appearance and communication module is connected with the DCS through the cable assembly; the optical lens group focuses light emitted by target flame, a focused light signal is transmitted to the photosensitive element through the optical fiber, the electrical parameter of the photosensitive element is related to the light of the target flame, the signal appearance and communication module collects the electrical parameter value of the photosensitive element, obtains the characteristic value of the light of the target flame, and uploads the characteristic value to the DCS through a cable channel; the thermal gas mass flowmeter with the LoRa wireless module is arranged at a cooling air inlet, is connected with the signal processing and communication module, detects the flow and the temperature of cooling air, reads the characteristic value of target flame light from the signal processing and communication module, and uploads the characteristic value to the DCS through the LoRa wireless channel, and the LoRa wireless module is additionally arranged on the DCS;

the cooling air is input from a cooling air inlet of the flame detector and divided into two paths: one path of air flows to the self-cleaning air outlet ring through the inner conduit; 20-40% of the other path of cooling air passes through the micropores, forms an air film on the outer surface of the outer guide pipe for cooling, and is finally discharged to the hearth, and 80-60% of the rest cooling air of the path passes through the outer guide pipe to the self-cleaning air outlet ring; the self-cleaning air outlet ring collects cooling air flowing in from the inner guide pipe and residual cooling air flowing in from the outer guide pipe, and air outlet collected by the two strands of cooling air is guided to the center of the lens to cool the lens and is finally discharged to a hearth.

The thermal gas mass flowmeter with the LoRa wireless module comprises a temperature sensor constant current source module, a temperature sensor signal conditioning module, a speed sensor PWM (pulse-width modulation) driving module, a speed sensor signal conditioning module, a signal processing and main control module, an annular flow equalizing plate and a LoRa wireless communication module, wherein the signal processing and main control module takes an STM32F103 chip as a core, and the LoRa wireless communication module is E32-TTL-100 in model number; under the action of the temperature sensor constant current source module, the compensation resistor R of the temperature sensor module_LPrecision resistor Rb output voltage V_LAnd Vb_LVoltage V of_LAnd Vb_LThe signals are output to a signal processing and main control module through a temperature sensor signal conditioning module; under the drive of the speed sensor PWM drive module, the speed resistance R of the speed sensor module_HPrecision resistor Ra output voltage V_HAnd Va_HVoltage V of_HAnd Va_HThe signals are output to a signal processing and main control module through a speed sensor signal conditioning module; STM32F103 pins 10, 11, 12, 13 and 14 of the signal processing and main control module are respectively connected with E32-TTL-100 pins 1, 2, 3, 4 and 5, and pins 6 and 7 of E32-TTL-100 are respectively connected with VCC and ground; STM32F103 pins 21 and 22 of the signal processing and main control module are accessed to USART ports of the signal processing and main control module;

the signal processing and main control module is used for processing the voltage V_L，V_H、Va_HCalculating the compensation resistance R_LResistance value, speed resistance R_HResistance value, temperature T of temperature sensor_LTemperature T of speed sensor_HAccording toT_HL＝T_H－T_L0≈T_H－T_LBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, the constant temperature difference requirement is met, a PWM control signal is generated, the output of a PWM driving module of the speed sensor is regulated, and T is_L0Is the temperature of the gas to be measured; calculating the mass flow q according to the formula (1)_m；

The theoretical model of a thermal gas mass flowmeter is shown as follows:

in the formula, q_mIs the mass flow rate; i is_HHeating current for speed sensor, R_HIs the resistance of the speed sensor, T_HIs the temperature of the speed sensor; t is_L0Is the temperature of the gas to be measured, T_LT is used in engineering for the measured gas temperature measured by a flowmeter temperature sensor (not shown in the formula)_LApproximate T_L0(ii) a A. B is an empirical constant;

the pipeline of the gas to be measured is provided with an annular flow equalizing plate, the gas to be measured is rectified by the annular flow equalizing plate, so that the speed of each point of the gas flow on the axial section of the pipeline is uniformly distributed, and a measuring rod of a flowmeter is positioned behind the annular flow equalizing plate; two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor R_LMeasuring hole at the bottom of measuring rod, speed resistor R_HThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor R_LAnd a velocity resistance R_HHeat conduction of (2).

The circuit of the temperature sensor module comprises a precision resistor Rb and a compensation resistor R which are connected in series_L(ii) a The other end of the precision resistor Rb and the terminals Point _ IS, Point _ Vb_L1 connected to output voltage Vb_LThe output of the temperature sensor constant current source module IS connected with a terminal Point _ IS; compensation resistor R_LThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connected_LAnd the series Point of (1) and the terminal Point _ V_L1 connected to each other, output voltage V_L(ii) a The circuit of the speed sensor module comprises a precision resistor Ra and a speed resistor R which are connected in series_H(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ Va_H1 connected to output voltage Va_HThe output of the speed sensor PWM driving module is connected to the terminal Point _ PWM 2; velocity resistor R_HThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connected_HAnd the series Point of (1) and the terminal Point _ V_H1 connected to each other, output voltage V_H(ii) a Compensation resistor R_LAnd a velocity resistance R_HThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference T_HL＝T_H－T_L0The temperature was set at 100 ℃.

The flow of the operation and maintenance method of the flame detector of the improved cooling device comprises an off-line flow of the flame detector and an on-line flow of the flame detector;

the variables are described as follows:

temperature, t

Flow rate, f

Upper limit of upper limit, UL

Lower limit, LL

Upper temperature limit T _ UL

A lower flow limit F _ LL;

off-line flow of flame detector to improve cooling device:

given that the upper limit of the cooling air temperature T _ UL is 150 ℃, and the lower limit of the cooling air flow F _ LL is 0.5m³/S

Secondly, setting a cooling air qualified temperature-flow cold quantity table, wherein Ti is an integer, i is more than or equal to 1 and less than or equal to N, and N is more than or equal to 1

Temperature of	T1＝-10	……	TN＝150
				Flow rate m3/S	≥0.5	≥……	≥1.5

Improving the on-line flow of the flame detector of the cooling device:

firstly, detecting the temperature t of cooling air

If T is more than T _ UL, the cooling air over-temperature alarm is carried out, and then

② detecting the flow f of cooling air

If F is less than F _ LL, the cooling air ultra-low flow rate alarm is carried out, and then

Checking the qualified temperature-flow cold quantity meter of cooling air, Fi corresponding to Ti

If f is less than Fi, the low flow of cooling air is alarmed, then

Reading, flame detector signal appearance and flame characteristic value + t + f of communication module

Uploading DCS through LoRa wireless communication module

And fifthly, returning to the step I.

Compared with the background technology, the invention has the following beneficial effects:

the vacuum aluminizing process sprays an aluminum film on the outer conduit of the fire detection probe, so that the radiant heat is reduced; the outer conduit is provided with micropores, and cooling air flowing through the outer conduit is divided into two parts; one path of air film cooling is formed on the outer surface of the outer conduit through the micropores on the outer conduit, so that the cooling potential of the double-layer cooling technology is fully exerted: the air duct design of the Venturi air outlet enables cooling air to be exhausted from the periphery of the front of the lens, the exhausted air is guided to the center of the lens, the cooling effect of the lens is improved, and the lens has a self-cleaning function; the flow and the temperature of cooling air are detected by adopting a thermal gas mass flow meter, a single-value binary function of the cooling capacity, the flow and the temperature of the cooling air is established, the hidden danger of blockage of a cooling air channel is eliminated, and the cooling reliability is improved; add the wireless redundant channel of loRa, upload the flow and the temperature data of cooling air to and flame information, improved the wired channel's of cable reliability.

Drawings

FIG. 1 is a view showing a structure of a flame detector with an improved cooling device;

fig. 2(a) is a schematic block diagram of a thermal gas mass flowmeter equipped with a LoRa wireless module;

fig. 2(b) is an installation diagram of the thermal gas mass flow meter;

fig. 3 is a circuit diagram of a temperature and speed sensor module.

Detailed Description

As shown in fig. 1, the flame detector of the improved cooling device is composed of a fire detection probe 10, a signal processing and communication module 20, a cable assembly 30 and a thermal gas mass flowmeter 40 configured with a LoRa wireless module, wherein the fire detection probe 10 comprises an optical lens group 11, a light guide fiber 12, a photosensitive element 13, an inner conduit 14, an outer conduit 15 and a self-cleaning air outlet ring 18; the inner conduit 14 is concentric with the outer conduit 15, the optical fiber 12 is positioned on the central axis of the inner conduit 14, the inner conduit 14 is embedded in the outer conduit 15, an aluminum film 16 is sprayed on the outer side of the outer conduit 15, micropores 17 are arranged on the outer conduit 15, the density of the distribution of the micropores 17 from the front end of the fire detection probe 10 to the outer wall of the furnace wall is dense → sparse → dense, and the optical lens group 11 and the self-cleaning air outlet ring 18 are positioned at the front end of the fire detection probe 10; the air outlet of the self-cleaning air outlet ring 18 adopts a Venturi air channel structure, the diffusion section of a Venturi throat is parallel to the lens, high-speed low-pressure cooling air is exhausted from the periphery in front of the lens, and the exhausted air is guided to the center of the lens;

the optical lens group 11 is connected with the photosensitive element 13 through the optical fiber 12, the photosensitive element 13 is connected with the signal management and communication module 20, and the signal management and communication module 20 is connected with the DCS through the cable assembly 30; the optical lens group 11 focuses light emitted by target flame, a focused light signal is transmitted to the photosensitive element 13 through the optical fiber 12, an electrical parameter of the photosensitive element 13 is related to the light of the target flame, and the signal processing and communication module 20 collects an electrical parameter value of the photosensitive element 13 to obtain a characteristic value of the light of the target flame and uploads the characteristic value to DCS through a cable wired channel; the thermal gas mass flowmeter 40 provided with the LoRa wireless module is arranged at a cooling air inlet, is connected with the signal processing and communication module 20, detects the flow and the temperature of cooling air, reads the characteristic value of target flame light from the signal processing and communication module 20, and uploads the characteristic value to the DCS through the LoRa wireless channel, and the LoRa wireless module is additionally arranged on the DCS;

the cooling air is input from a cooling air inlet of the flame detector and divided into two paths: one path passes through the inner conduit 14 to the self-cleaning air outlet ring 18; 20-40% of the other path of cooling air passes through the micropores 17, forms an air film on the outer surface of the outer guide pipe for cooling, and is finally discharged to the hearth, and 80-60% of the rest cooling air in the path passes through the outer guide pipe 15 to the self-cleaning air outlet ring 18; the self-cleaning air outlet ring 18 collects the cooling air flowing in from the inner duct 14 and the residual cooling air flowing in from the outer duct 15, and the air outlet formed by the collection of the two strands of cooling air is guided to the center of the lens to cool the lens and finally discharged to the hearth.

Description 1: since the flame detector is a commercial product, the signal processing and communication module 20 and the cable assembly 30 are well known in the art, and only mentioned here and not discussed; the optical lens set 11, the optical fiber 12, the photosensitive element 13 and the inner catheter 14 of the fire detection probe 10 are also in the known knowledge domain, and only mentioned here and not discussed herein. Discussion focuses on the improvements made by the present application: the device comprises an outer conduit 15, an aluminum spray film 16, a self-cleaning air outlet ring 18 and an additional thermal gas mass flowmeter 40 with a LoRa wireless module.

As shown in fig. 2(a) and 2(b), the thermal gas mass flowmeter 40 configured with the LoRa wireless module includes a temperature sensor constant current source module 100, a temperature sensor module 200, a temperature sensor signal conditioning module 300, a speed sensor PWM driving module 400, a speed sensor module 500, a speed sensor signal conditioning module 600, a signal processing and main control module 700, and a ring-shaped average current meterThe flow plate 800 and the loRa wireless communication module 900, the signal processing and main control module 700 uses an STM32F103 chip as a core, and the model of the loRa wireless communication module 900 is E32-TTL-100; under the action of the temperature sensor constant current source module 100, the compensation resistor R of the temperature sensor module 200_LPrecision resistor Rb output voltage V_LAnd Vb_LVoltage V of_LAnd Vb_LThe signal is output to the signal processing and main control module 700 through the temperature sensor signal conditioning module 300; speed resistance R of speed sensor module 500 driven by speed sensor PWM driving module 400_HPrecision resistor Ra output voltage V_HAnd Va_HVoltage V of_HAnd Va_HThe signals are output to the signal processing and main control module 700 through the speed sensor signal conditioning module 600; the STM32F103 pins 10, 11, 12, 13 and 14 of the signal processing and main control module 700 are respectively connected with the E32-TTL-100 pins 1, 2, 3, 4 and 5, and the pins 6 and 7 of the E32-TTL-100 are respectively connected with VCC and ground; the pins 21 and 22 of the STM32F103 of the signal processing and main control module 700 are accessed to USART ports of the signal processing and communication module 20;

the signal processing and main control module 700 is based on the voltage V_L，V_H、Va_HCalculating the compensation resistance R_LResistance value, speed resistance R_HResistance value, temperature T of temperature sensor_LTemperature T of speed sensor_HAnd according to T_HL＝T_H－T_L0≈T_H－T_LBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, the constant temperature difference requirement is met, a PWM control signal is generated, the output of the speed sensor PWM driving module 400 is adjusted, and T_L0Is the temperature of the gas to be measured; calculating the mass flow q according to the formula (1)_m；

The theoretical model of a thermal gas mass flowmeter is shown as follows:

in the formula, q_mIs the mass flow rate; i is_HHeating current for speed sensor, R_HIs the resistance of the speed sensor, T_HIs the temperature of the speed sensor; t is_L0Is the temperature of the gas to be measured, T_LT is used in engineering for the measured gas temperature measured by a flowmeter temperature sensor (not shown in the formula)_LApproximate T_L0(ii) a A. B is an empirical constant;

the pipeline of the gas to be measured is provided with an annular flow equalizing plate 800, the gas to be measured is rectified by the annular flow equalizing plate 800, so that the speed of the gas flow at each point on the axial section of the pipeline is uniformly distributed, and a measuring rod of a flowmeter is positioned behind the annular flow equalizing plate 800; two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor R_LMeasuring hole at the bottom of measuring rod, speed resistor R_HThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor R_LAnd a velocity resistance R_HHeat conduction of (2).

As shown in FIG. 3, the circuit of the temperature sensor module 200 includes a precision resistor Rb and a compensation resistor R connected in series_L(ii) a The other end of the precision resistor Rb and the terminals Point _ IS, Point _ Vb_L1 connected to output voltage Vb_LThe output of the temperature sensor constant current source module 100 IS connected to the terminal Point _ IS; compensation resistor R_LThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connected_LAnd the series Point of (1) and the terminal Point _ V_L1 connected to each other, output voltage V_L(ii) a The circuit of the speed sensor module 500 includes a precision resistor Ra and a speed resistor R connected in series_H(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ Va_H1 connected to output voltage Va_HThe output of the speed sensor PWM driving module 400 is connected to the terminal Point _ PWM 2; velocity resistor R_HThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connected_HAnd the series Point of (1) and the terminal Point _ V_H1 connected to each other, output voltage V_H(ii) a Compensation resistor R_LAnd a velocity resistance R_HThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference T_HL＝T_H－T_L0The temperature was set at 100 ℃.

Description 2: wheatstone electricity is abandoned in the textThe bridge temperature compensation circuit structure is used for designing an independent measured gas temperature measuring circuit; the temperature measurement circuit continues to follow the terminology and notation of the bridge temperature compensation circuit. Known values of Rb, Ra and I_bL＝0.5/R_EXT(ii) a Measuring the voltage drop of the precision resistor Ra to obtain the current Ia flowing through the Ra_H(ii) a Measuring compensation resistance R_LVelocity resistor R_HVoltage drop, obtaining compensation resistance R_LVelocity resistor R_HResistance value; from the compensation resistance R_LVelocity resistor R_HResistance value, find Pt20 platinum resistor R_L、R_HCorresponding T_L、T_H. A circuit diagram of a temperature sensor constant current source module; a circuit diagram of a speed sensor PWM driving module, a circuit diagram of a temperature and speed sensor signal conditioning module, a circuit diagram of a signal processing and main control module and a schematic diagram of a constant temperature difference Fuzzy-PI dual-mode undisturbed switching control algorithm; please refer to the thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control, application No. 2019111479510, applied by the subject group.

The flow of the flame detector of the improved cooling device comprises an off-line flow of the flame detector and an on-line flow of the flame detector;

the variables are described as follows:

temperature, t

Flow rate, f

Upper limit of upper limit, UL

Lower limit, LL

Upper temperature limit T _ UL

A lower flow limit F _ LL;

off-line flow of flame detector to improve cooling device:

given that the upper limit of the cooling air temperature T _ UL is 150 ℃, and the lower limit of the cooling air flow F _ LL is 0.5m³/S

Secondly, setting a cooling air qualified temperature-flow cold quantity table, wherein Ti is an integer, i is more than or equal to 1 and less than or equal to N, and N is more than or equal to 1

Temperature of	T1＝-10	……	TN＝150
				Flow rate m3/S	≥0.5	≥……	≥1.5

Improving the on-line flow of the flame detector of the cooling device:

firstly, detecting the temperature t of cooling air

If T is more than T _ UL, the cooling air over-temperature alarm is carried out, and then

② detecting the flow f of cooling air

If F is less than F _ LL, the cooling air ultra-low flow rate alarm is carried out, and then

Checking the qualified temperature-flow cold quantity meter of cooling air, Fi corresponding to Ti

If f is less than Fi, the low flow of cooling air is alarmed, then

Reading, flame detector signal processing and flame characteristic value + t + f of communication module 20

Uploading DCS through LoRa wireless communication module 900

And fifthly, returning to the step I.

Note: INT (t +0.5) performs the cooling wind temperature t, rounded.