在沼氣工程運(yùn)行過程中,需要采用儀器去感知生產(chǎn)過程的狀態(tài)。沼氣工程中主要涉及兩類檢測(cè)儀表: 檢測(cè)溫度、壓力、流量、液位等的熱工測(cè)量?jī)x表;檢測(cè)固體懸浮物濃度、濁度、PH、COD、揮發(fā)性脂防酸、沼氣成分等的物性與成分儀表。下面沼氣生物脫硫設(shè)備廠家給大家簡(jiǎn)單介紹幾種常用于自控系統(tǒng)的檢測(cè)儀表,希望對(duì)大家有所幫助。
In the process of biogas engineering operation, it is necessary to use instruments to sense the state of the production process. In biogas engineering, there are mainly two kinds of measuring instruments: thermodynamic measuring instruments for detecting temperature, pressure, flow rate and liquid level; physical properties and composition instruments for detecting solid suspended matter concentration, turbidity, PH, COD, acid-proof volatile lipids, biogas composition, etc. The following biogas biological desulfurization equipment manufacturers give you a brief introduction to several commonly used automatic control system testing instruments, hoping to help you.
1.壓力檢測(cè)儀表
1. Pressure measuring instruments
電測(cè)式壓力檢測(cè)儀表是利用金屬或半導(dǎo)體的物理特性,直接將壓力轉(zhuǎn)換為電壓或電流信號(hào)輸出。也可利用彈性體受壓產(chǎn)生的形變,通過電阻應(yīng)變片將形變轉(zhuǎn)換為電壓或電流信號(hào)輸出。為保證彈性元件工作在有效形變范圍內(nèi),被測(cè)大壓力值不應(yīng)超過滿量程的3/4,小壓力值不應(yīng)低于全量程的1/3。
Electrical pressure measuring instrument is to use the physical characteristics of metal or semiconductor to directly convert pressure into voltage or current signal output. The deformation of elastomer under pressure can also be transformed into voltage or current signal output by resistance strain gauge. In order to ensure that the elastic element works within the effective deformation range, the maximum pressure measured should not exceed 3/4 of the full range, and the minimum pressure should not be less than 1/3 of the full range.
壓力傳感器獲取的壓力信息,由壓力變送器或壓力開關(guān)轉(zhuǎn)換為標(biāo)準(zhǔn)電信號(hào)輸出,可以遠(yuǎn)程輸出。由傳感器、變送器或壓力開關(guān)組成的壓力檢測(cè)儀可用于監(jiān)測(cè)管道、沼氣發(fā)酵裝置以及儲(chǔ)氣裝置內(nèi)的壓力。壓力測(cè)量值常常用作報(bào)警參數(shù)。
Pressure information acquired by pressure sensor can be converted from pressure transmitter or pressure switch to standard electrical signal output, which can be output remotely. The pressure detector composed of sensors, transmitters or pressure switches can be used to monitor the pressure in pipelines, biogas fermentation devices and gas storage devices. Pressure measurements are often used as alarm parameters.
2.流量檢測(cè)儀表
2. Flow meter
流量檢測(cè)儀表包括測(cè)量單位時(shí)間流量的流量計(jì)和測(cè)量流體流過總量的積算儀,多數(shù)流量檢測(cè)儀同時(shí)具備測(cè)量流量和總量的功能。
Flow detection instruments include flow meters for measuring unit time flow and accumulator for measuring total flow of fluid. Most flow detectors have the function of measuring both flow and total flow.
檢測(cè)流量的方式很多,其中電磁流量計(jì)因其傳感器的光滑測(cè)量管內(nèi)無阻流部件,使儀表壓力損失極小,且不易堵塞,在檢測(cè)液固兩相介質(zhì)流量方面有優(yōu)勢(shì),故具有一定導(dǎo)電率的污水流量適合用電磁流量計(jì)檢測(cè),但若污水中含有較多鐵磁性物質(zhì)及大量水泡時(shí)會(huì)影響測(cè)量精度。電磁流量計(jì)在安裝上要求前、后都有直管段,其長(zhǎng)度分別不小于5倍、3倍管內(nèi)徑。
There are many ways to detect the flow rate, among which the electromagnetic flowmeter has advantages in detecting the flow rate of liquid-solid two-phase media because of its smooth sensor without obstruction components, which makes the pressure loss of the instrument very small and is not easy to block. Therefore, the sewage flow with certain conductivity is suitable for the detection of electromagnetic flowmeter, but if the sewage contains more ferromagnetic substances and a large number of bubbles, it will affect the measurement. Quantity accuracy. The installation of electromagnetic flowmeter requires that there are straight pipe sections before and after installation, whose length is not less than 5 times and its diameter is 3 times respectively.
對(duì)沼氣流量的檢測(cè),一般借用天然氣的商用流量檢測(cè)儀表。因沼氣具有腐蝕性,故檢測(cè)儀表的抗腐性和儀表之間存在矛盾。目前上的較為的技術(shù)為超聲波氣體測(cè)量技術(shù),超聲波流量計(jì)與傳統(tǒng)的壓差式流量計(jì)、渦街流量計(jì)、熱式流量計(jì)相比,具有更強(qiáng)的抗腐蝕性,更寬的量程比和更小的壓損,能夠滿足高壓、大流量的氣體計(jì)量要求,并且不存在易于磨損的機(jī)械可動(dòng)部件,能保證長(zhǎng)期使用精度不變,具有較高的測(cè)量精確性。值得一提的是,銳意自控自主研發(fā)的超聲波沼氣流量計(jì)BF-3000B還具備同時(shí)測(cè)量CH4濃度和沼氣流量的功能。
For the detection of biogas flow, the commercial flow meter of natural gas is usually used. Because biogas is corrosive, there is a contradiction between the anti-corruption and the price of the instrument. At present, the leading technology in the world is the ultrasonic gas measurement technology. Compared with the traditional pressure differential flowmeter, vortex flowmeter and thermal flowmeter, the ultrasonic flowmeter has stronger corrosion resistance, wider range ratio and smaller pressure loss. It can meet the requirements of gas measurement with high pressure and large flow rate, and there is no mechanical movable parts which are easy to wear and tear. Long-term use accuracy is unchanged, with high measurement accuracy. It is worth mentioning that the BF-3000B ultrasonic biogas flowmeter, which is designed to be self-controlled and independently developed, also has the function of simultaneously measuring CH4 concentration and biogas flow rate.
3.溫度檢測(cè)儀表
3. Temperature Measuring Instrument
溫度是影響微生物活性的主要因素之一,沼氣發(fā)酵過程需要進(jìn)行溫度控制,因此,溫度檢測(cè)儀表不可或缺。溫度傳感器中,適用于檢測(cè)沼氣發(fā)酵料液溫度的典型測(cè)溫元件是熱電阻,其測(cè)溫電路采用不平衡電橋。
Temperature is one of the main factors affecting microbial activity. The fermentation process of biogas needs temperature control. Therefore, temperature detection instrument is indispensable. In temperature sensor, thermal resistance is a typical temperature measuring element suitable for detecting the temperature of biogas fermentation liquid, and its temperature measuring circuit adopts unbalanced bridge.
溫度傳感器直接安裝在沼氣發(fā)酵裝置上,與變送器的距離可能較遠(yuǎn),傳感器與變送器的連接通常采用三線制接法,即用三根導(dǎo)線,其中一根串聯(lián)在電源支路里,另兩根分別接在兩個(gè)相鄰的橋壁上。三線制接法可基本連接導(dǎo)線造成的測(cè)量誤差。
The temperature sensor is directly installed on the biogas fermentation device, which may be far away from the transmitter. The sensor and the transmitter are usually connected by three wires, one of which is connected in series in the power supply branch, and the other two are connected on two adjacent bridge walls. The three-wire connection method can basically eliminate the measurement errors caused by the connecting wires.
與溫度傳感器配接的二次儀表主要包括溫度變送器、數(shù)字溫度顯示儀和溫度巡檢儀。
The secondary instruments connected with temperature sensors mainly include temperature transmitter, digital temperature display instrument and temperature patrol instrument.
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