CN104237056A - Humidity and temperature monitoring-based method for detecting moisture of grains at internal points of granary - Google Patents

Abstract

The invention provides a humidity and temperature monitoring-based method for detecting moisture of grains at internal points of a granary. The method comprises the following steps: building a relational model between the equilibrium moisture and the temperature and the humidity of the grains at the internal points of the granary, determining initial values of all parameters in a formula by adopting a static weighing method and multivariate statistics regression; building a database of parameters of different grain varieties after model parameter correction; acquiring the corresponding temperature and humidity values of the internal points of the grains based on a system for detecting the humidity and the temperature of the internal points of the granary; acquiring the corresponding temperature and relative humidity value of single point or multiple points inside the granary through data acquisition, and computing by directly calling the rapid moisture detection formula and formula parameter values corresponding to different grains by a system, and therefore, the moisture of the single point or the multiple points inside the granary can be rapidly detected.

Description

A kind of silo internal point grain measurement of moisture content method based on warm and humid monitoring

Technical field

The present invention relates to the moisture monitoring in grain storage safety management and computing method, particularly a kind of silo internal point moisture detecting method based on temperature-humidity monitoring, the method realizes the equilibrium moisture of direct-detection grain by the inner humiture observation system of silo.

Background technology

Grain is important agricultural product, is the valuable source being related to national economy.The existing a large amount of grain depot of China, there is the multi-form silo of some in each storehouse, is intended to the safety guaranteeing grain.Grain condition monitoring is the key of silo management.At present, the common method of monitoring grain feelings is both at home and abroad, at the inner mounting temperature sensor of silo, by the temperature of monitoring grain heap, evaluates the quality safety situation of grain, and takes the ventilating such as cooling, precipitation, modulation of suitable intensity.Here the problem existed, the safe condition of grain is not only cereal temperature index, and the moisture of grain and the humiture of grain seed surrounding air should be comprised, therefore single cereal temperature that relies on judges in practice, there is the case of many erroneous judgements, sometimes cause the going mouldy of grain, sometimes cause insect pest, sometimes cause quantity to lose.In order to address this problem, the humidity detection technology of silo internal point is moving towards application, damp and hot regulation and control math equation (Wu Zidan piled by the grain that the eighties in 20th century, China expert proposed with relative humidity and absolute humidity are expressed, 1987), give the funtcional relationship of (definitely) humidity and grain moisture content and temperature relatively, journey has established the technical foundation of China's silo mechanical ventilation, is called as WU model.WU model equation is as follows:

${\mathrm{ERH}}_r=\exp \{\frac{\frac{D}{222}\×(e^{\frac{B_1-M}{A_1}}-e^{\frac{B_2-M}{A_2}})\×(1737.1-\frac{474242}{273+t})+D\×\left({1-e}^{\frac{B_1-M}{A_1}}\right)+202}{87.72}$

In formula: ERH _rfor grain equilibrium relative humidity (ERH) (%), M is grain moisture content (% wet basis), and t is cereal temperature (DEG C), A ₁, B ₁, B ₂, D is 5 parameters of WU model.

Within 1991, the Ministry of Commerce is based on WU model, has issued " mechanical ventilation in grain storage technical regulation "; Within 2002, upgrade to industry standard (LS/T1202-2002).The industry standard " mechanical ventilation in grain storage technical regulation " (LS/T1202-2002) issued for 2002, combines parameters such as temperature, humidity and dew points the task management carrying out silo safety exactly.WU model essence solves grain and piles funtcional relationship between the water percentage of the equilibrium relative humidity (ERH) of inner grain or the absolute humidity of grain and grain and cereal temperature, because the inverse function relation of this relation is never solved, so function and inverse function relation unification chart are expressed among industry standard, like this to look into the technical conditions that curve method determines grain machinery ventilation.Looking into curve method can by the equilibrium relative humidity (ERH) of grain or the absolute humidity of grain and the temperature of grain, indirectly check in the moisture of grain, also can be changed by ventilation condition, predict the moisture of grain, but ventilate and automatically control or in grain measurement of moisture content and prediction instrument have inconvenience in intelligent control system and exploitation silo more setting up grain machinery like this.

Therefore, the present invention on moisture relative equilibrium basis, provides direct relational model between silo internal point grain equilibrium moisture and temperature and humidity in hypothesis grain heap, and realizes with this equilibrium moisture detecting grain.The relational model of application grain equilibrium moisture and equilibrium relative humidity (ERH) and temperature is just easy to determine that cooling is ventilated, precipitation ventilates and the damp condition of conditioning and aeration, for mechanical ventilation task management provides important evidence.

Summary of the invention

The present invention is directed to a kind of silo internal point grain measurement of moisture content method based on warm and humid monitoring of proposition of above problem, the method is relatively simple, and calculated amount is little, effectively can ensure to detect grain moisture content, reduce erroneous judgement of ventilating.

For realizing said method, the application is achieved in that

Step 1, utilizes static weighing method to measure the EMC data of different cultivars sample desorb and absorption under different epidemic disaster.

Step 2, utilizes the data group of step 1, selects and sets up grain moisture content, temperature and humidity relational model, and the model according to setting up carries out parameter value estimation and verification, sets up different grain variety parameter database after Confirming model parameter value.

Step 3, sets up the inner warm and humid monitoring system of silo, utilizes this systems axiol-ogy to go out the temperature and humidity of silo internal point and the determined model of invocation step 2 and model parameter, calculates the inner single-point of silo or multiple spot moisture value.

Step 4, according to national mechanical ventilation in grain storage standard LS/T1202-2002, on the basis of analysis temperature, humidity and moisture distribution, carries out silo cooling, precipitation, the task management such as modified.

Further, described step 1 comprises the following steps:

Step 1.1, after sample screening, processed under constant low temperature.For desorption curve, the also low temperature that adds water is adopted after even 2 weeks, to carry out equilibrium moisture mensuration to seed sample.

Step 1.2, equilibrium moisture is tested; Utilize different saturated salt solution to produce constant vapour pressure under different steady temperature, adopt static weighing method to measure the sorption and desorption equilibrium moisture of different grain kind.

Further, in described step 2, select and set up grain moisture content, temperature and humidity relational model is EMC=f (ERHr, T) form:

$\mathrm{EMC}=\sqrt[\mathrm{\α}]{\frac{\ln (1-{\mathrm{ERH}}_r)-\ln {\mathrm{ERH}}_r-A-C\·T^{\mathrm{\β}}}{B}}$

Wherein, EMC is moisture (fractional representation), ERH _rbe the relative humidity (fractional representation) of cereal, A, B, C, α, β are equation parameters, and T is environment temperature (DEG C).By the test figure in step 1 model parameter value estimated and and different cultivars grain epidemic disaster and water relation test in obtain parameter value and contrast, correct, thus determine parameter value.The parameter database of various grain is set up, the query calls when actual measurement according to parameters obtained value.

Formula described in step 2, can make α, β be respectively 1 and simplify further, can obtain 3 parameter water content detection models:

$\mathrm{EMC}=\frac{\ln (1-{\mathrm{ERH}}_r)-\ln {\mathrm{ERH}}_r-A-C\·T}{B}.$

Further, described step 3 comprises the steps:

Step 3.1, based on the silo networking multiple spot Temperature and Humidity built and control system, gathers the epidemic disaster that grain internal point is corresponding; By data acquisition, the inner single-point of silo or the temperature corresponding to multiple spot and rh value can be obtained.

Step 3.2, the determined model and parameter of invocation step 2, calculates the inner single-point of silo or multiple spot moisture value.

Step 3.3, on the display interface set up, by display or LED real-time digital, chart display silo internal point cereal temperature, humidity and moisture.

Further, in described step 4, mechanical ventilation in grain storage standard LS/T1202-2002 is as following table:

In table, t ₁, t ₂be respectively atmospheric temperature and cereal temperature, t _l1, t _l2be respectively atmospheric dew point temperature and grain dewpoint temperature, Ps ₁for air absolute humidity, Ps ₂for grain temperature is t ₂time grain absolute humidity values, Ps ₂₁for grain moisture content subtracts 1% and grain temperature equals atmospheric temperature t ₁time absolute humidity values, Ps ₂₂for grain moisture content man adds 2.5% and grain temperature equals atmospheric temperature t ₂time absolute humidity values, Ps ₂₃for current grain temperature t ₂lower grain moisture content adds the grain absolute humidity values of 2.5%.

The invention has the beneficial effects as follows: based on the temperature-humidity monitoring of silo internal point, provide a kind of simple and clear moisture detecting method, solve in foodstuff preservation management process, by looking into the inconvenience of curve method determination grain moisture content, decrease the erroneous judgement of grain security state, this method can as the gordian technique of water content detection, Forecast and control in silo.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part.In the accompanying drawings:

Fig. 1 is the schematic flow sheet of a kind of silo internal point grain measurement of moisture content method based on warm and humid monitoring of the present invention.

Fig. 2 is parameter correction iterative process.

Fig. 3 is the TT&C system block diagram of the inner warm and humid monitoring system of silo in the present invention.

Embodiment:

Below in conjunction with drawings and Examples, the present invention is described in further detail.

As shown in Figure 1, a kind of silo internal point moisture detecting method based on temperature-humidity monitoring, specifically comprises the following steps:

Step 1, utilizes static weighing method to measure the EMC data of different cultivars sample desorb and absorption under different epidemic disaster.

Step 2, utilizes the data group of step 1, selects and sets up grain moisture content, temperature and humidity relational model, carrying out parameter estimation and verification according to the model determined, sets up different grain variety parameter database after obtaining best model parameter value.

Step 3, sets up the inner warm and humid monitoring system of silo, utilizes this systems axiol-ogy to go out the temperature and humidity of silo internal point and the determined model of invocation step 2 and model parameter, calculates the inner single-point of silo or multiple spot moisture value.

Step 4, according to national mechanical ventilation in grain storage standard LS/T1202-2002, on the basis of analysis temperature, humidity and moisture distribution, carries out silo cooling, precipitation, the task management such as modified.

Wherein, the relational model in step 1 is set up and is determined as follows:

The first step, preparation of samples.After sample screening, under constant low temperature, adopt phosphorus pentoxide dewater solids method to reduce unimolecular layer water in grain, make seed initial water content drop to 5.0% (wet basis) below.For desorption curve, the also low temperature that adds water is adopted after even 2 weeks, to carry out equilibrium moisture mensuration to seed sample.

Second step: equilibrium moisture is tested.Utilize 9 kinds of saturated salt (chlorination file, potassium acetate, magnesium chloride, sal tartari, magnesium nitrate, cupric chloride, sodium chloride, potassium chloride, potassium nitrate) solution 5 kinds of steady temperatures (10,20,25,30 and 35 DEG C) under produce constant vapour pressure, adopt static weighing method to measure paddy equilibrium moisture.The equilibrium humidity that various salts produces at different temperatures is as following table:

Next carry out step 2, according to the data that step 1 pilot scale test obtains, regression equation solves.Utilize the non-linear regression method of the SPSS software parameters that the different cereal of matching is corresponding in model when resolving and adsorb respectively, grain measurement of moisture content model of the present invention is EMC=f (ERH _r, T) and form:

$\mathrm{EMC}=\sqrt[\mathrm{\α}]{\frac{\ln (1-{\mathrm{ERH}}_r)-\ln {\mathrm{ERH}}_r-A-C\·T^{\mathrm{\β}}}{B}}$

ERH in described formula _rbe the relative humidity (fractional representation) of cereal, EMC is moisture (fractional representation).A, B, C, α, β are equation parameters, t _αenvironment temperature (DEG C).Described formula 1 to simplify further by making α, β, is called five parameter WU.W.F models, is called the simple and clear WU.W.F model of three parameters after simplification before simplification.

Foundation due to model is based on static weighing method, therefore also needs humiture and the water relation experiment of carrying out different grain kind at silo.Sampled measurements is gone out grain moisture content and contrasts with the model parameter value estimated value obtained by the test figure in step 1, by continuous iterative computation, adjustment model parameter, finally reaches error minimize.

As shown in Figure 2, step is as follows for concrete trimming process:

Original model parameter is determined by static weighing method measurement, is input in model, just can calculates the moisture of master pattern by initial parameter values A, B, C, α, β of matching.The actual moisture of different humiture grain samples is measured, the moisture value that comparison model obtains and the error of surveying moisture value by oven drying method.If error size does not meet the requirement of precision, then adjust parameter, calculate again and compare.

Constantly adjust initial parameter values by iterative process, reduce model moisture and the mean square deviation of surveying moisture.When the accuracy requirement met, iteration terminates, the model parameter after can being adjusted.

By measuring different cultivars grain, set up the parameter database of various grain, the query calls when actual measurement.Model parameter after adjustment is if table 2 is to table 5.Parameters in the grain equilibrium moisture detection formula of determined different grain kind such as table 2,3,4,5 is respectively supplemental characteristic and the degree of fitting of the crops such as paddy, corn and wheat.R ²it is the coefficient of determination; MRE% is average relative percentage error.

The simple and clear WU.W.F model parameter value of three parameters that table 2 is expressed with ERH=f (EMC, t) form

The simple and clear WU.W.F model parameter value of three parameters that table 3 is expressed with EMC=f (ERH, t) form

The five parameter WU.W.F model parameter values that table 4 is expressed with ERH=f (EMC, t) form

The five parameter WU.W.F model parameter values that table 5 is expressed with EMC=f (ERH, t) form

Following step 3, sets up the inner warm and humid monitoring system of silo, utilizes this systems axiol-ogy to go out the temperature and humidity of silo internal point, and the water content detection model in calling system and model parameter value corresponding to different cereal, calculate the inner single-point of silo or multiple spot moisture value.

Figure 3 show the block diagram of the inner warm and humid monitoring system of silo.The present invention, in order to realize the water percentage gathering silo internal point accurately and real-time, adopts wireless sensor network node to monitor the humiture of different depth paddy in grain heap, is gathered and show image data by acquisition terminal.Utilize wireless transmission method that the data of collection are sent to host computer server, according to equilibrium moisture model prediction Rice Kernel Moisture Content, realize the Real-Time Monitoring of Rice Kernel Moisture Content in silo, temperature, humidity, meet the demand of reliability and real-time.

1) based on the silo networking multiple spot Temperature and Humidity built and control system, epidemic disaster corresponding to grain internal point is gathered by Temperature Humidity Sensor.Collection signal is involved signal conversion and sends together with the data of temperature sensor collection and be stored in host computer by humidity sensor after filtration, thus obtains the inner single-point of silo or the temperature corresponding to multiple spot and rh value.

2) water content detection model and model parameter value corresponding to different cereal in calling system database, utilizes the epidemic disaster value gathered to calculate the inner single-point of silo or multiple spot moisture value.

3) on the display interface set up, by the temperature of display or LED real-time digital, chart display silo internal point, humidity and moisture.

Last step 4 is exactly the humiture by grain epidemic disaster and equilibrium moisture and air, and system determines whether to exceed setting range.If go beyond the scope, sound and light alarm also carries out ventilating management according to industry ventilation standard (LS/T1202-2002).If meet, cooling is ventilated, precipitation ventilates and the temperature and humidity conditions of conditioning and aeration, sends Signal Regulation ventilation equipment, thus carry out mechanical ventilation task management by host computer.

In the present invention, the inner warm and humid monitoring system of institute's silo of setting up is primarily of hardware components and software section composition.

Hardware components mainly comprises: microprocessor, display, input-output unit, alarm unit, storage unit, Temperature Humidity Sensor group (temperature-humidity monitoring point is no less than 1), controlled quentity controlled variable input-output unit form.Microprocessor is for the treatment of, analysis and control data; Display is used for showing determination and analysis result in graphical form, and shows man-machine message exchange window; Input-output unit comprises keyboard, printer and mouse; When unsafe condition appears in alarm unit, give the alarm with acoustooptic form; Temperature Humidity Sensor, for monitoring the temperature and humidity of diverse location in silo, transmits data by the form of limited/infinite net to microprocessor; Controlled quentity controlled variable input-output unit is for controlling the equipment of mechanical ventilating.

Software section mainly comprises: system management module, temperature-humidity signal acquisition module, moisture computing module, alarm control module, prediction module.System management module is for coordinating hardware, data direction of transfer between software and people; Temperature-humidity signal acquisition module patrols and examines the temperature and humidity of diverse location in silo by certain sample frequency, and stores; Moisture computing module, according to the temperature gathered and (relative humidity of grain) humidity, calculates the moisture of grain and stores; Alarm control module, according to temperature, humidity and moisture three parameters, carries out ventilating according to industry standard (LS/T1202-2002), carries out sound and light alarm when there is dangerous situation; Prediction module, according to the forecast data of FUTURE ENVIRONMENT weather, carries out the prediction of grain security state in silo.

A kind of silo internal point moisture detecting method based on temperature-humidity monitoring of the present invention; not by the restriction of above-mentioned case study on implementation; everyly utilize principle of the present invention, method or form, the technical scheme formed through conversion, replacement or combine is all in protection scope of the present invention.

Claims (1)

1., based on a silo internal point grain measurement of moisture content method for warm and humid monitoring, it is characterized in that, comprise the following steps:

Step 1, utilizes static weighing method to measure the EMC data of different cultivars sample desorb and absorption under different epidemic disaster;

Step 2, utilizes the data group of step 1, selects and sets up grain moisture content, temperature and humidity relational model, and the model according to setting up carries out parameter value estimation and verification, sets up different grain variety parameter database after Confirming model parameter value;

Step 3, sets up the inner warm and humid monitoring system of silo, utilizes this systems axiol-ogy to go out the temperature and humidity of silo internal point and the determined model of invocation step 2 and model parameter, calculates the inner single-point of silo or multiple spot moisture value;

Step 4, according to national mechanical ventilation in grain storage standard LS/T1202-2002, on the basis of analysis temperature, humidity and moisture distribution, monitoring silo, carries out silo cooling, precipitation, the task management such as modified.

Silo internal point grain measurement of moisture content method based on warm and humid monitoring according to claim 1, it is characterized in that, described step 1 comprises the following steps:

Step 1.1, after sample screening, processed under constant low temperature.For desorption curve, the also low temperature that adds water is adopted after even 2 weeks, to carry out equilibrium moisture mensuration to seed sample;

Step 1.2, equilibrium moisture is tested; Utilize different saturated salt solution to produce constant vapour pressure under different steady temperature, adopt static weighing method to measure the equilibrium moisture of different grain kind.

Silo internal point grain measurement of moisture content method based on warm and humid monitoring according to claim 1, is characterized in that: in described step 2, select and set up grain moisture content, temperature and humidity relational model is EMC=f (ERHr, T) form:

$\mathrm{EMC}=\sqrt[\mathrm{\α}]{\frac{\ln (1-{\mathrm{ERH}}_r)-\ln {\mathrm{ERH}}_r-A-C\·T^{\mathrm{\β}}}{B}}$

In, EMC is moisture (fractional representation), ERH _rbe the relative humidity (fractional representation) of cereal, A, B, C, α, β are equation parameters, and T is environment temperature (DEG C).By the test figure in step 1 model parameter value estimated and and different cultivars grain epidemic disaster and water relation test in obtain parameter value and contrast, correct, thus determine parameter value, the parameter database of various grain is set up, the query calls when actual measurement according to parameters obtained value;

Described formula, can make α, β be respectively 1 and simplify further, can obtain 3 parameter water content detection models:

$\mathrm{EMC}=\frac{\ln (1-{\mathrm{ERH}}_r)-\ln {\mathrm{ERH}}_r-A-C\·T}{B}.$

Silo internal point grain measurement of moisture content method based on warm and humid monitoring according to claim 1, is characterized in that:

In described step 3, comprise the steps:

Step 3.1, based on the silo networking multiple spot Temperature and Humidity built and control system, gathers the epidemic disaster that grain internal point is corresponding; By data acquisition, the inner single-point of silo or the temperature corresponding to multiple spot and rh value can be obtained;

Step 3.2, the determined model and parameter of invocation step 2, calculates the inner single-point of silo or multiple spot moisture value;

Step 3.3, on the display interface set up, by display or LED real-time digital, chart display silo internal point cereal temperature, humidity and moisture.