容積式流量計：應(yīng)用與選型介紹（中英文）
什么是容積流量計
What Is Volumetric Flow Meter
容積流量計是一種能夠測量在設(shè)定時間內(nèi)流經(jīng)測量位置的流體體積的儀器。容積式流量計作為一種機械流量計，是常見的容積流量計類型。它可以測量高粘度和腐蝕性流體的體積流量。
A volumetric flow meter is an instrument that can measure the volume of fluid passing through the measurement location within a set period of time. A positive displacement flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive fluids.
容積式流量計的工作原理是什么？
How Does A Volumetric Flow Meter Work ?
容積式流量計是一種利用機械測量元件將流體連續(xù)分割成一個已知體積的流量計，通過反復(fù)充排流體來累積流體總量。
在給定流量計的工況下，計量空間的容積是確定的。只需測量轉(zhuǎn)子的旋轉(zhuǎn)次數(shù)，即可獲得流經(jīng)流量計的流體的累積體積。
The positive displacement flow meter is a flow meter that uses mechanical measuring elements to continuously divide the fluid into a single known volume, and repeatedly fill and discharge the volume of fluid to accumulate the total amount of fluid.
Under the conditions of a given flow meter, the volume of the metering space is determined. As long as the number of rotations of the rotor is measured, the cumulative value of the volume of fluid passing through the flow meter can be obtained.
容積式流量計的類型
Types Of Positive Displacement Flowmeter
為了滿足生產(chǎn)中各種介質(zhì)和不同工況下的流量測量需求，人們生產(chǎn)了各種類型的容積式流量計。其中，主要有齒輪式流量計、雙轉(zhuǎn)子流量計和腰輪式流量計三種類型。
1. 齒輪式容積流量計
橢圓齒輪流量計又稱定排量流量計，簡稱PD流量計。這種流量計的殼體內(nèi)裝有兩個轉(zhuǎn)子，它們直接或間接嚙合，并在流量計進出口之間的壓差作用下旋轉(zhuǎn)。通過齒輪的旋轉(zhuǎn)，齒輪與殼體之間“計量空間”內(nèi)的流體被連續(xù)排出。通過測量齒輪的轉(zhuǎn)數(shù)，即可獲得流經(jīng)流量計的流體量。橢圓齒輪流量計測量精度高，適用于測量高粘度介質(zhì)的流量，但不適用于含有固體顆粒的流體（固體顆粒會卡住齒輪，導(dǎo)致無法測量流量）。如果被測液體介質(zhì)中含有氣體，也會造成測量誤差。
2. 雙轉(zhuǎn)子（螺桿）流量計
雙轉(zhuǎn)子流量計是最新一代容積式流量計，又稱UF流量計或螺桿流量計。它特別適用于稀油、輕油、重油以及含砂量和含水量高的原油。被測液體的粘度范圍很廣。工業(yè)液體的計量流量計可現(xiàn)場指示，并可直接讀取代碼進行分發(fā)。它可以輸出電脈沖信號，該信號傳輸至二級儀表或計算機，形成自動控制、自動檢測和數(shù)據(jù)處理系統(tǒng)。
3. 腰輪流量計
腰輪流量計又稱羅茨流量計。腰輪流量計主要用于各行業(yè)工業(yè)管道中大口徑氣體、液體和蒸汽介質(zhì)流體的流量測量。腰輪流量計可用于各種清潔液體的流量測量，尤其適用于油品的測量，也可改裝成氣體流量計。其精度最高，可達0.1-0.5級。其主要缺點是：體積大、重量重、壓力損失大、運行過程中振動大等。
In order to meet the requirements of various media and different working conditions for flow measurement in production, various types of positive displacement flowmeters have been produced. Among them, there are three types of gear flowmeters, dual rotor flowmeters and waist wheel flowmeters.
1. Gear Type Positive Displacement Flowmeter
Oval gear flowmeter is also called fixed displacement flowmeter, referred to as PD flowmeter. The casing of this flowmeter is equipped with two rotors, which are directly or indirectly meshed with each other, and rotate under the action of the pressure difference between the inlet and the outlet of the flowmeter. Through the rotation of the gear, the fluid filled in the “metering space” between the gear and the housing is continuously discharged. By measuring the number of rotations of the gear, the amount of fluid passing through the flowmeter can be obtained. The oval gear flowmeter has high measurement accuracy and is suitable for measuring the flow of high-viscosity media, but it is not suitable for fluids containing solid particles (solid particles will jam the gear, making it impossible to measure the flow). If the measured liquid medium contains gas, it will also cause measurement errors.
2. Double rotor (screw) flowmeter
Dual-rotameter flowmeters are the latest generation of positive displacement flowmeters, also known as UF —” flowmeters or screw flowmeters. It is especially suitable for thin oil, light oil, heavy oil, crude oil with large sand content and large water content. The viscosity range of the liquid to be measured is large. The metering flowmeter of industrial liquids can be indicated on site, and the code can be read directly and can be distributed. It can output electric pulse signal, which is transmitted to secondary instrument or computer to form automatic control, automatic detection and data processing system.
3. Waistwheel flowmeter
The waist wheel flowmeter is also called the Roots flowmeter. The waist wheel flowmeter is mainly used for the flow measurement of large-diameter gas, liquid, and steam medium fluids in industrial pipelines in various industries. The waist wheel flowmeter can be used for flow measurement of various clean liquids, especially for oil measurement, and can also be made into a flowmeter for measuring gas. Its meter has the highest accuracy, up to 0.1-0.5 level. Its main disadvantages are: large volume, heavy weight, large pressure loss, large vibration during operation, etc.
容積式流量計工作原理
VOLUMETRIC FLOW METER WORKING PRINCIPLE
容積式流量計的工作原理：
當(dāng)流體流經(jīng)流量計時，流量計的入口和出口之間會產(chǎn)生一定的壓差。流量計的旋轉(zhuǎn)部件（稱為轉(zhuǎn)子）在該壓差的作用下旋轉(zhuǎn)，并將流體從入口排至出口。在此過程中，流體反復(fù)填充流量計的“計量空間”，并持續(xù)地被送至出口。在給定的流量計工況下，只要測量轉(zhuǎn)子的旋轉(zhuǎn)次數(shù)，即可確定計量空間的容積。進而可以得到流經(jīng)流量計的流體的累計容積。
橢圓齒輪流量計的工作原理：
兩個橢圓齒輪具有特殊的形狀，相互滾動接觸旋轉(zhuǎn)。P1 和 P2 分別代表入口壓力和出口壓力。顯然，P1 > P2。如圖 1(a) 所示，下齒輪在兩側(cè)壓差的作用下逆時針旋轉(zhuǎn)，它是主動齒輪；上齒輪兩側(cè)壓差相等，不產(chǎn)生旋轉(zhuǎn)扭矩，它是從動齒輪，由下齒輪驅(qū)動順時針旋轉(zhuǎn)。如圖 1(b) 所示，在壓差的作用下，兩個齒輪都產(chǎn)生旋轉(zhuǎn)扭矩并繼續(xù)旋轉(zhuǎn)。當(dāng)安裝在圖 1(c) 所示位置時，上齒輪成為主動齒輪，下齒輪成為從動齒輪，繼續(xù)旋轉(zhuǎn)至與圖 1(a) 相同的位置，完成一個循環(huán)。一個循環(huán)動作會排出齒輪與殼體壁之間四個新月形腔體內(nèi)的流體體積，這稱為流量計的“循環(huán)容積”。
The working principle of the positive displacement flowmeter:
when the fluid passes through the flowmeter, a certain pressure difference will be generated between the inlet and outlet of the flowmeter. The rotating part of the flowmeter (referred to as the rotor) rotates under the action of this pressure difference and discharges the fluid from the inlet to the outlet. During this process, the fluid fills the “metering space” of the flowmeter again and again, and is then continuously sent to the outlet. Under the conditions of a given flow meter, the volume of the metering space is determined as long as the number of rotations of the rotor is measured. The cumulative value of the volume of fluid passing through the flowmeter can then be obtained.
The working principle of oval gear flow meter:
The two oval gears have a special shape that rolls against each other for contact rotation. P1 and p2 represent the inlet pressure and the outlet pressure, respectively. Obviously, p1>p2. The lower gear in Figure 1(a) rotates counterclockwise under the action of the pressure difference on both sides, which is the driving gear; the upper gear is equal to the pressure on both sides. No rotational torque is generated, it is a driven wheel, which is driven by the lower gear and rotates clockwise. At the position shown in Figure 1(b), both gears generate rotational torque under the action of differential pressure and continue to rotate. When it is installed in the position shown in Figure 1(c), the upper gear becomes the driving wheel, and the lower gear becomes the driven wheel, which continues to rotate to the same position as shown in Figure 1(a) to complete a cycle. One cycle action expels the fluid volume of the four crescent-shaped cavities enclosed between the gear and the housing wall, which is called the “cycle volume” of the flowmeter.
METRIC FLOW METER WORKING PRINCIPLE
橢圓齒輪流量計的工作原理是什么？
設(shè)流量計的“循環(huán)容積”為υ，在一定時間內(nèi)齒輪的旋轉(zhuǎn)次數(shù)為N，則該時間內(nèi)流過流量計的流體容積為V，
則V=Nυ (1)
橢圓齒輪的旋轉(zhuǎn)通過磁封聯(lián)軸器和傳動減速機構(gòu)傳遞到計數(shù)器，直接指示流過流量計的總流量。如果加裝發(fā)送裝置和電子顯示儀表，則遠程傳輸只能顯示瞬時流量或累計流量。
腰輪式羅茨流量計的工作原理：
腰輪式流量計又稱羅茨流量計。其結(jié)構(gòu)特點是：流量計殼體內(nèi)有一個測量腔，測量腔內(nèi)有一對或兩對腰輪，可沿切線方向旋轉(zhuǎn)。一對傳動齒輪與兩個搜索輪同軸安裝在流量計外殼外部，它們相互嚙合，使兩個腰輪能夠相互連接。流體通過側(cè)向元件和隔板從入口流向出口，流量恒定。只需知道計量室的容積，并記錄腰輪的轉(zhuǎn)數(shù) N，即可得到流經(jīng)流量計的流體體積 V。顯然，腰輪流量計的流量為：V=4Nv (2-2)
雙轉(zhuǎn)子（螺桿）流量計的工作原理：
雙轉(zhuǎn)子（螺桿）流量計的一對特殊齒形螺旋轉(zhuǎn)子直接嚙合，無相對滑動，也無同步齒輪。轉(zhuǎn)子在入口和出口處的小壓差驅(qū)動下旋轉(zhuǎn)。因此，轉(zhuǎn)子的轉(zhuǎn)數(shù)與流體的累計流量成正比，轉(zhuǎn)子的轉(zhuǎn)速與流體的瞬時流量成正比。轉(zhuǎn)子的轉(zhuǎn)數(shù)通過磁耦合傳遞至流量計數(shù)器，從而顯示流經(jīng)流量計（管道）的流量。
雙轉(zhuǎn)子（螺桿）流量計是一種設(shè)計獨特的容積式流量計，主要用于液體流量測量。
How Oval Gear Flow Meters Work ？
Let the “circulation volume” of the flowmeter be υ, and the number of gear rotations in a certain period of time is N, then the volume of fluid flowing through the flowmeter during this time is V,
Then V=Nυ (1)
The rotation of the oval gear is transmitted to the counter through the magnetic seal coupling and the transmission reduction mechanism to directly indicate the total amount flowing through the flowmeter. If the sending device is attached, and the electric display instrument is added, the remote transmission is only instantaneous flow or cumulative flow.
The working principle of the Roots flowmeter of the waist wheel flowmeter:
The waist wheel flowmeter is also called the Roots flowmeter. Its structural characteristics are: there is a measuring chamber in the shell of the flowmeter, and there are one or two pairs of waist wheels that can rotate tangentially in the measuring chamber. A pair of transmission gears are installed coaxially with the two search wheels outside the casing of the flowmeter, and they mesh with each other so that the two waist wheels can be linked with each other. There is a constant flow of fluid separated by the side and elements and sent from the inlet to the outlet. Just know the volume of the metering chamber space. And record the number of rotations of the waist wheel N. The fluid volume V through the flow basin meter can be obtained. Obviously, for the flow rate of the waist wheel flowmeter: V=4Nv (2-2)
Working principle of double rotor (screw) flowmeter:
A pair of special-toothed helical rotors of the dual-rotor (screw) flowmeter are directly meshed, without relative sliding, and without synchronizing gears. The rotor is driven to rotate by a small pressure difference at the inlet and outlet. Therefore, the number of revolutions of the rotor is proportional to the cumulative flow of the fluid, and the rotational speed of the rotor is proportional to the instantaneous flow of the fluid. The number of revolutions of the rotor is transmitted to the meter counter through the magnetic coupling, which shows the flow through the flow meter (through the pipeline).
The dual rotor (screw) flowmeter is a uniquely designed positive displacement flowmeter mainly used for liquid flow measurement.
容積式流量計適用于哪些應(yīng)用？
Where Are The Positive Displacement Used For?
容積式流量計特別適用于測量粘性流體，例如油、冷凝液、樹脂和液態(tài)食品。對于高粘度介質(zhì)的流量，其他流量計難以測量，而容積式流量計可以精確測量，精度可達±0.2%。因此，容積式流量計常用于昂貴介質(zhì)（如石油、天然氣等）的總量測量。
Positive displacement flow meters are particularly suitable for the flow of viscous fluids such as oil, condensate, resins and liquid foods. For the flow of high viscosity medium, other flowmeters are difficult to measure, but positive displacement flowmeters can accurately measure the accuracy of ±0.2%. Therefore, positive displacement flowmeters are often used in the total measurement of expensive media (oil, natural gas, etc.).
容積式流量計的應(yīng)用
POSITIVE DISPLACEMENT VOLUMETRICFLOW METER APPLICATION
容積式流量計的應(yīng)用：
容積式流量計、差壓式流量計和浮球式流量計是應(yīng)用最廣泛的三種流量計，常用于昂貴介質(zhì)（如石油、天然氣等）的總量計量。
常用的容積式流量計包括橢圓齒輪流量計、雙轉(zhuǎn)子流量計和腰輪式流量計。
橢圓齒輪流量計的應(yīng)用：
橢圓齒輪流量計（又稱位移流量計、齒輪流量計）是一種容積式流量計，也是一種高精度流量計。橢圓齒輪流量計可采用不同材料（如鑄鐵、鑄鋼、304不銹鋼、316不銹鋼）制造，用于精確測量管道中液體的連續(xù)或間歇流量或瞬時流量。橢圓齒輪流量計特別適用于重油、聚乙烯醇、樹脂等高粘度介質(zhì)的流量測量，例如化工、石油、制藥、電力、冶金和食品等行業(yè)的流量測量。
雙轉(zhuǎn)子流量計的應(yīng)用：
雙轉(zhuǎn)子流量計屬于世界上最新一代容積式流量計，也稱為UF-‖流量計或螺旋流量計。雙轉(zhuǎn)子流量計是一種用于測量和控制管道內(nèi)液體流量的精密儀器。廣泛應(yīng)用于石油、化工、冶金、電力、交通運輸、船舶、油庫、碼頭、罐車等部門，尤其適用于原油、成品油、輕烴等工業(yè)液體的流量測量。該流量計可現(xiàn)場顯示流量，并可直接讀取字碼。它還可以配備變送器輸出電脈沖信號，并將信號傳輸至二級儀表或計算機，形成自動控制、自動檢測和數(shù)據(jù)處理系統(tǒng)。
腰輪流量計的應(yīng)用：
腰輪流量計又稱羅茨流量計，主要用于各行業(yè)工業(yè)管道中大口徑氣體、液體和蒸汽介質(zhì)流體的流量測量。腰輪流量計也可用于各種清潔液體的流量測量，尤其適用于油品的流量測量，也可改裝成氣體流量計。其精度極高，可達0.1-0.5級。腰輪流量計主要應(yīng)用于石油化工行業(yè)、油庫、平臺、碼頭、水氣站等場所的裝卸、運輸、油品銷售計量、定量交付、原材料進出計量、燃料消耗量等。
Application of positive displacement flowmeter:
Positive displacement flowmeter, differential pressure flowmeter and float flowmeter are listed as the three most widely used flowmeters, and are often used in the total measurement of expensive media (oil, natural gas, etc.).
Commonly used volumetric flowmeters include oval gear flowmeters, dual rotor flowmeters, and waist wheel flowmeters.
Applications of oval gear flowmeters:
Oval gear flowmeter (also known as displacement flowmeter, gear flowmeter) is a kind of positive displacement flowmeter, and it is a kind of high precision flowmeter. The oval gear flowmeter can be made of different materials (cast iron, cast steel, 304 stainless steel, 316 stainless steel) for precise continuous or intermittent measurement of liquid flow or instantaneous flow in pipelines. The oval gear flowmeter is especially suitable for flow measurement of heavy oil, polyvinyl alcohol, resin and other media with higher viscosity, such as flow measurement in chemical, petroleum, pharmaceutical, electric power, metallurgy and food industries.
Application of dual rotor flowmeter:
The dual-rotor flowmeter belongs to the latest generation of positive displacement flowmeters in the world, also known as UF-‖ flowmeters or screw flowmeters. Double rotameter is a precision instrument for the measurement and control of liquid flow in pipelines. Widely used in petroleum, chemical, metallurgy, electric power, transportation, ships, oil depots, terminals, tank trucks and other departments, especially for crude oil, refined oil, light hydrocarbons and other industrial liquids. The metering flowmeter can indicate on-site, and the word code can be read directly and It can be equipped with a transmitter to output electrical pulse signals, which can be transmitted to secondary instruments or computers to form automatic control, automatic detection and data processing systems.
Application of waist wheel flowmeter:
The waist wheel flowmeter is also called the Roots flowmeter. The waist wheel flowmeter is mainly used for the flow measurement of large-diameter gas, liquid, and steam medium fluids in industrial pipelines in various industries. The waist wheel flowmeter can be used for flow measurement of various clean liquids, especially for oil measurement, and can also be made into a flowmeter for measuring gas. Its meter has the highest accuracy, up to 0.1-0.5 level. The waist wheel flowmeter is mainly used in the petroleum and petrochemical industry, oil depot oil platform, wharf, water gas station for loading, shipping, oil sales measurement, quantitative delivery, raw material in and out measurement, fuel consumption, etc.
如何選擇合適的容積式流量計？
How To Choose The Right Positive Displacement Flowmeter?
容積式流量計性能選擇
選擇容積式流量計時應(yīng)考慮以下五個要素：（1）流量范圍；（2）被測介質(zhì)的物理特性；（3）測量精度；（4）耐壓（工作壓力）和壓降；（5）用途。
（1）流量范圍
容積式流量計的流量范圍與被測介質(zhì)的類型（主要取決于流體的粘度）、使用特性（連續(xù)工作或間歇工作）、測量精度等因素有關(guān)。
（2）被測介質(zhì)的物理特性
被測介質(zhì)的物理特性主要考慮流體的粘度和腐蝕性。
（3）測量精度
容積式流量計是目前測量精度最高的流量計之一。
現(xiàn)場條件對測量精度的主要影響因素是被測介質(zhì)的粘度和溫度。
（4）耐壓性（工作壓力）和壓力損失
流量計的工作壓力應(yīng)由流量計殼體承受。不同材質(zhì)的壓力部件應(yīng)采用不同的工作壓力要求，以避免不安全使用。
（5）使用目的
用于計量和計費的流量計主要考慮其測量精度，可作為現(xiàn)場指示儀表；用于過程控制的流量計主要考慮其可靠性，應(yīng)配備變送器、計數(shù)器、調(diào)節(jié)和顯示儀表等各種配套設(shè)備。
Choice of Positive Displacement Flowmeter Performance
The following five elements should be considered in the performance selection of positive displacement flowmeter: (1) flow range; (2) physical properties of the measured medium; (3) measurement accuracy; (4) pressure resistance (working pressure) and pressure loss; (5) purpose of use.
⑴ flow range
The flow range of the positive displacement flowmeter is related to the type of the measured medium (mainly determined by the viscosity of the fluid), the characteristics of use (continuous work or intermittent work), measurement accuracy and other factors.
(2) Physical properties of the measured medium
The physical properties of the measured medium mainly consider the viscosity and corrosiveness of the fluid.
⑶ measurement accuracy
Positive displacement flowmeter is one of the flowmeters with the highest measurement accuracy at present.
The major influences of site conditions on the measurement accuracy are the influence of the viscosity of the measured medium and the influence of temperature.
⑷ Pressure resistance (working pressure) and pressure loss
The working pressure of the flowmeter should be endured by the flowmeter shell. Different requirements for the working pressure should be used for pressure components of different materials to avoid unsafe use.
⑸ Purpose of use
The flowmeter used for measurement and accounting mainly considers its measurement accuracy, which can be an on-site indicating instrument; the flowmeter used for process control mainly considers its reliability, and should have various supporting equipment such as transmitters, counters, adjustment and display instruments, etc. .
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