在沼氣工程運行過程中,需要采用儀器去感知生產過程的狀態(tài)。沼氣工程中主要涉及兩類檢測儀表: 檢測溫度、壓力、流量、液位等的熱工測量儀表;檢測固體懸浮物濃度、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備廠家給大家簡單介紹幾種常用于自控系統的檢測儀表,希望對大家有所幫助。
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.壓力檢測儀表
1. Pressure measuring instruments
電測式壓力檢測儀表是利用金屬或半導體的物理特性,直接將壓力轉換為電壓或電流信號輸出。也可利用彈性體受壓產生的形變,通過電阻應變片將形變轉換為電壓或電流信號輸出。為保證彈性元件工作在有效形變范圍內,被測大壓力值不應超過滿量程的3/4,小壓力值不應低于全量程的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轉換為標準電信號輸出,可以遠程輸出。由傳感器、變送器或壓力開關組成的壓力檢測儀可用于監(jiān)測管道、沼氣發(fā)酵裝置以及儲氣裝置內的壓力。壓力測量值常常用作報警參數。
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.流量檢測儀表
2. Flow meter
流量檢測儀表包括測量單位時間流量的流量計和測量流體流過總量的積算儀,多數流量檢測儀同時具備測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.
檢測流量的方式很多,其中電磁流量計因其傳感器的光滑測量管內無阻流部件,使儀表壓力損失極小,且不易堵塞,在檢測液固兩相介質流量方面有優(yōu)勢,故具有一定導電率的污水流量適合用電磁流量計檢測,但若污水中含有較多鐵磁性物質及大量水泡時會影響測量精度。電磁流量計在安裝上要求前、后都有直管段,其長度分別不小于5倍、3倍管內徑。
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.
對沼氣流量的檢測,一般借用天然氣的商用流量檢測儀表。因沼氣具有腐蝕性,故檢測儀表的抗腐性和儀表價格之間存在矛盾。目前上的較為的技術為超聲波氣體測量技術,超聲波流量計與傳統的壓差式流量計、渦街流量計、熱式流量計相比,具有更強的抗腐蝕性,更寬的量程比和更小的壓損,能夠滿足高壓、大流量的氣體計量要求,并且不存在易于磨損的機械可動部件,能保證長期使用精度不變,具有較高的測量精確性。值得一提的是,銳意自控自主研發(fā)的超聲波沼氣流量計BF-3000B還具備同時測量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)酵過程需要進行溫度控制,因此,溫度檢測儀表不可或缺。溫度傳感器中,適用于檢測沼氣發(fā)酵料液溫度的典型測溫元件是熱電阻,其測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,傳感器與變送器的連接通常采用三線制接法,即用三根導線,其中一根串聯在電源支路里,另兩根分別接在兩個相鄰的橋壁上。三線制接法可基本消除連接導線造成的測量誤差。
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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