轉子流量計介紹(中英文)
第一章:轉子流量計原理
Chapter 1: Principle of Rotameters
本章將討論什么是轉子流量計、它們的結構以及工作原理。
This chapter will discuss what rotameters are, their construction, and how they function.
什么是轉子流量計?
What Is A Rotameter?
轉子流量計是一種測量封閉管內單位時間流體體積流量的裝置。轉子流量計應用有多種類型,包括化學品注入/計量和儲罐覆蓋。轉子流量計是一種使用帶有封閉自由浮子的刻度玻璃管測量流體流量的儀表。
轉子流量計也稱為變面積流量計,用于測量液體或氣體通過轉子流量計的錐形管時的體積流量。液體或氣體的流動使儀表的浮子升高,增加了介質可以通過的面積。流量越大,浮子升得越高。
A rotameter is a device that measures the flow of fluid volume per unit of time in a closed tube. There are several types of rotameter applications, including chemical injection/dosing and tank blanketing. A rotameter is a gauge for measuring fluid flow using a graduated glass tube with an enclosed free float.
Also known as variable area flow meters, rotameters are used to measure liquid or gas volumetric flow rates as they pass through the tapered tube of the rotameter. The flow of the liquid or gas raises the meter’s float, increasing the area through which the media may pass. The larger the amount of flow, the higher the float is raised.
轉子流量計可用于吹掃應用,以保持工藝管線暢通。在簡單的流量測量中,警報或電氣輸出可以檢查流量狀況并對其進行連續(xù)控制。
A rotameter can be used for purge applications to keep process lines clear. In simple flow measurement, an alarm or an electrical output makes it possible to check flow conditions and control them continuously.
轉子流量計的構造
Construction of Rotameters
轉子流量計包含一根底部直徑較小的透明錐形垂直管。該管改變其橫截面積,以便通過給予浮子恒定的下降來影響浮子。浮子的形狀可以對流動產生更小的阻礙。
A rotameter contains a transparent, tapered, vertical tube with a small diameter at the bottom. This tube changes its cross-sectional area in order to affect the float by giving it a constant drop. The float is shaped to create minimum hindrance to the flow.
玻璃管的外緣標有線性刻度。錐形管可以由塑料、金屬或玻璃制成,它們都有不同的用途;例如,不透明液體用于金屬管,而氣體管則含有其他氣體和液體。此外,金屬管可能使用不同密度的金屬,包括鉛和鋁,而浮子主要由不銹鋼制成。
A linear scale is marked on the outer margin of the glass tube. The conical tube can be made up of plastic, metal, or glass, with all of them having different uses; for example, opaque liquids are used in metal tubes, whereas gas tubes contain other gasses and liquids. In addition, metal tubes might use metals of different densities, including lead and aluminum, while the floats are mainly made of stainless steel.
轉子流量計如何工作
How Rotameters Work
流體從底部進入管并從頂部逸出。這種流體就是其流量被測量的流體。當儀器中沒有流量時,浮子將停留在管底部。在這種情況下,浮子的總直徑幾乎等于玻璃管的內徑。
Fluid enters the tube from the bottom and escapes through the top. This fluid is the one whose flow is measured. The float will rest at the bottom of the tube when there is no flow in the instrument. In such a situation, the total diameter of the float is nearly equal to the inside diameter of the glass tube.
當流體進入管內時,環(huán)形開口的流通面積增大,從而使浮子向上移動。它向上移動,直到其上、下表面壓力差產生的提升力開始等于浮子重量。由于轉子流量計中流量的增加,升力和壓差會暫時增加。隨后,浮子移動到頂部并增加環(huán)形開口的面積。因此,升力將減小,流體的力將變得與浮子重量相同。通過改變與流量相關的環(huán)形開口的面積,壓力差保持不變。玻璃管上標記的刻度表示流量。
The flow area of the annular opening increases when the fluid enters the tube, thus making the float move upwards. It moves upwards until the lifting strength produced from the difference in pressure across its upper and lower surfaces begins to equal the float weight. The lifting force and pressure difference will temporarily increase due to the flow rate increase in the rotameter. Afterward, the float travels to the top and increases the area in the annular opening. Due to this, the lifting force will decrease, and the force of the fluid will become the same as the float weight. The difference in pressure remains the same by changing the area of the annular opening in relation to the flow rate. The scale marked on the glass tube indicates the flow rate.
使用轉子流量計時,必須在給定的條件下對給定的氣體或流體進行校準。通常,條件及其流量范圍和測量單位都寫在流量計的側面。在使用轉子流量計時,始終建議根據流量條件的任何變化來校正流量管讀數。通常,制造商會詳細說明儀表所需的校正,但情況并非總是如此。
When using rotameters, calibration must be undertaken for a given gas or fluid at a given set of conditions. Normally, the conditions are written on the sides of the flow meter along with its range of flow and the units of measurement. In using rotameters, one is always advised to correct the flow tube readings according to any changes in flow conditions. Usually, manufacturers detail the required corrections for the meters, but this is not always the case.
轉子流量計的工作原理
Working Principle of a Rotameter
轉子流量計中使用的公式之一是:
Q=kA√GH
符號:
Q = 體積流量
k = 常數
A = 浮子和管壁之間的環(huán)形面積
g = 重力
h = 浮子的壓降
One of the formulas used in the rotameters is:
Q=kA√GH
Where:
Q = volumetric flow rate
k = a constant
A = annular area contained between the float and the wall of the tube
g = the force of gravity
h = the pressure drop of the float
由于其優(yōu)點,轉子流量計成為使用廣泛的變面積流量計。它由一個浮子組成,當流體通過時浮子會在管子中移動。由于體積而產生的更多流量對浮子施加更大的壓力,從而將其提升得更高。在液體中,浮力與流動液體的速度合二為一,從而使浮子升高。在氣體中,浮力被忽略為氣體速度,壓力將浮子分配到一定的高度。
通常,管子垂直設置,無流動,浮子位于底部。但當流體通過時,浮子開始上升到管的頂部。浮子移動時獲得的高度通常與流體流動的速率成正比。當向上的力現(xiàn)在等于浮子的重量時,該過程達到平衡,同時也使浮子處于固定位置而不移動。此時,可以輕松讀取讀數,包括密度讀數和流體的流動阻力(粘度)。
使用流量調節(jié)閥,可以手動調節(jié)轉子流量計中的流量。轉子流量計的名稱源于早期的設計,早期的設備具有自由浮子,其隨著氣體和流體壓力的變化而旋轉。
Because of its advantages, a rotameter is the most widely used variable area flow meter. It consists of a float that moves through a tube as the fluid passes through. More flow due to volume exerts a greater pressure on the float, thus lifting it even higher. In liquids, buoyancy becomes one with the velocity of the flowing liquid, thus raising the float. In gasses, buoyancy is left out as the speed of the gas, and the pressure assigns the float to a certain height.
Commonly, the tube is set up vertically with no flow and the float at the bottom. But just as the fluid passes through, the float begins to elevate up to the top of the tube. The height gained by the float as it moves is generally proportional to the rate at which the fluid flows. The process reaches equilibrium when the upward force now equals the weight of the float, also giving the float a fixed position with no movement. At this moment, readings can be easily taken, including readings of the density and the fluid’s resistance to flow (viscosity).
Using flow regulation valves, one can manually adjust the flow in the rotameter. The name rotameter was gained from the early designs where the early equipment had free floats which rotated in relation to the change in gas and fluid pressures.
空氣和水等常用流體已經隨轉子流量計提供了校準數據和讀數刻度。制造商通常提供部分標準信息,例如校準表、標準流量值、列線圖和計算尺。
Generally used fluids such as air and water already have their calibration data and reading scales provided together with the rotameters. The manufacturers normally provide part of this standard information, such as the calibration tables, standard flow values, nomographs, and slide rules.
轉子流量計的特性
Characteristics of a Rotameter
轉子流量計的線性度
Linearity of a Rotameter
面積與單位時間內流經變量流量計的體積成正比,從而使這些流量計具有相同刻度的增量。轉子流量計刻度的線性度誤差約為 5%。
The area is proportional to the volume flowing in a unit of time through a variable meter, thus making these meters have increments of equal scale. The linearity of a rotameter scale is amiss at about 5%.
轉子流量計的微分
Differential of a Rotameter
在變面積流量計中,通過浮子的壓力損失是恒定的。在較高流量下,由于配件中的摩擦損失,儀表中的壓差會增加。
The loss of pressure through the float is constant in the variable area meter. At a higher flow rate, the differential in the meter increases due to the friction losses in the fittings.
轉子流量計的精度
Accuracy of a Rotameter
常用的精度是刻度讀數的 ±2%。由于用戶的校準和刻度長度,該刻度精度大大提高。
±2% of the scale reading is the most-used accuracy. Due to the user’s calibration and the scale length, this scale accuracy increases considerably.
轉子流量計的容量
Capacity of a Rotameter
水0.5cm 3 /min、空氣30cm 3標準/min為流量計的大量程范圍。
0.5 cm3 /min of water and 30 cm3 standard/min of air are the large-scale capacity range of the flow meters.
轉子流量計更低的管道要求
Minimum Piping Requirement of a Rotameter
安裝時無需考慮直管程序的連接或長度或遵循儀表。
Installations can be made without considering the connections or lengths of straight pipe procedures or following the meter.
轉子流量計的腐蝕性液體
Corrosive Liquid of a Rotameter
油、焦油、硫酸和黑液都是腐蝕性液體,可以在面積計中正確處理。
Oil, tar, sulfuric acid, and black liquor are corrosive liquids that can be correctly handled in an area meter.
轉子流量計的壓降
Pressure Drop of a Rotameter
通過將浮子放置在較大的儀表上,流量可以處理非常低的壓力損失。
The flow rates can handle a very low-pressure loss by placing floats on larger gauges.
概括
Summary
轉子流量計的特點是結構簡單,因此成本較低。由于大多數流量計都帶有線性刻度,因此很容易讀取讀數。準確度在總讀數的 ±2% 之內,允許讀數出現(xiàn)一點誤差。最后,轉子流量計是一種易于安裝的儀器。
A rotameter’s characteristics include its simple construction, thus providing a low cost. It is easy to take readings because the rotameter contains a linear scale with most meters. Accuracy, which is within ±2% of the total reading, allows a little room for errors in the readings. Lastly, the rotameter is an easy-to-install instrument.
轉子流量計的組件
Components of a Rotameter
轉子流量計的組件包括:
The components of a rotameter include:
轉子流量計的計量管
Metering Tubes of a Rotameter
為了獲得堅固且均勻的管子,計量管在心軸中制造并退火以消除內應力。這個過程使得計量管具有更高的再現(xiàn)性和更多的互換性。此外,還創(chuàng)建了帶有彎曲元件的錐形計量管,以擴展范圍下端的刻度。通常,安全屏蔽玻璃管用于測量液體和氣體。金屬管用于應用不透明液體、溫度和壓力要求非常高的區(qū)域。在一些轉子流量計設計中,使用塑料管是因為其成本較低且抗沖擊強度較高。
To obtain strong and uniform tubes, the metering tubes are created in a mandrel and annealed to have no internal stresses. This process leads to the metering tubes having greater reproducibility and more interchangeability. In addition, conical metering tubes with curved elements are created to extend the graduations at the lower end of the range. Generally, safety-shielded glass tubes are used for measuring both liquids and gasses. Metal tubes are used in areas where opaque liquids are applied, where temperature and pressure requirements are noticeably high. In some rotameter designs, plastic tubes are used due to their lower cost and high impact strength.
轉子流量計的浮子
Floats of a Rotameter
浮子采用耐腐蝕和耐容量改變的材料制成,例如不銹鋼。這些按照儀表的容量進行分組。轉子流量計受被測流體粘度變化影響的方式可能受到浮子形狀的影響或決定。具有尖角或邊緣的浮子可能對粘度的變化不敏感。
作用在浮子上的力有三種:重量、浮力和阻力。重量是恒定的向下的力,而浮力是恒定的向上的力。阻力是具有向上方向的可變力。它們由不同密度的金屬制成,例如鉛和鋁;也可以使用玻璃和塑料。浮子設計為球形,適合小流量。
The floats are made using materials that resist corrosion and capacity modification, such as stainless steel. These are grouped in terms of the capacities of the meters. The way in which a rotameter will be affected by changes in the viscosity of the fluid measured can be affected or determined by the shape of the float. Floats with sharp corners or edges are likely to be insensitive to changes in viscosity.
There are three forces that act on the float: weight, buoyancy, and drag force. Weight is a constant downward force, whereas buoyancy is a constant upwards force. Drag force is a variable force having an upward direction. They are constructed using metals of different densities, like lead and aluminum; glass and plastic can also be used. Floats are designed to be spherical for small flows.
轉子流量計的特點
Features of a Rotameter
儀器必須包含聲音或視覺警報,以提醒用戶危險情況。儀器還必須包含控制器功能,以便正確使用和調諧儀器。這些有助于設備接收輸入信號,并將其處理為輸出信號,以便于通信。要更改轉子流量計正在處理的命令,儀器必須是可編程的。這是通過在可編程儀表中插入內置微處理器來實現(xiàn)的。這些微處理器可以根據材料、范圍和輸出進行電子調節(jié)。
轉子流量計必須包含一些記錄器或累加器功能,因為它們可以累加受控材料和介質的數量。可以設置記錄器功能來處理數據記錄并將該數據記錄在計算機系統(tǒng)中,以便將來使用,即使轉子流量計未使用。該相同的功能稍后可以以顯示的圖表或表格的形式生成數據摘要。
最后,轉子流量計可以適應衛(wèi)生環(huán)境,例如醫(yī)療或食品加工場所。
The instruments must contain audible or visual alarms to alert users of a dangerous situation. The instruments must also contain controller functions for the proper use and tuning of the instruments. These help the devices receive an input signal that can be processed into an output signal for easier communication. To change the commands being processed by the rotameter, the instrument must be programmable. This is achieved by inserting a built-in microprocessor in the programmable meters. These microprocessors can be adjusted electronically depending on the materials, ranges, and outputs.
A rotameter must contain some recorder or totalizer functions, as these totalize the amount of material and media controlled. A recorder function can be placed to process data logging and record this data in a computer system so it can be used in the future, even if the rotameter is not in use. This same function can later produce a summary of the data in the form of displayed charts or tables.
Finally, rotameters can accommodate use in sanitary environments such as medical or food processing places.
轉子流量計的精度
Accuracy of a Rotameter
實驗室轉子流量計可在 4:1 范圍內校準至約 0.50% AR 的精度。工業(yè)轉子流量計的準確度可能較低,因為在 10:1 范圍內其精度為 1-2% FS。
可以在調整閥門開度并觀察刻度的同時手動設置流量。由于粘度變化很小,轉子流量計不會變化太大。這一點取決于設備的設計,因為使用球測量的設備最敏感,而較大的設備則不太敏感。粘度極限通常由浮子形狀和構成轉子流量計的材料決定。一旦儀器超過其粘度極限,就需要校正粘度讀數。
如果流體密度發(fā)生變化,可以使用兩個浮子。在這兩個浮子中,一個取決于流體體積,另一個將校正流體密度。低粘度流體(例如汽油、噴氣燃料和其他輕質烴)最適合使用質量流量轉子流量計。由于浮力導致密度變化后,浮子位置可以改變,這是由于浮子密度與流體密度相匹配而引起的。
A laboratory rotameter can be calibrated to an accuracy of about 0.50% AR over a 4:1 range. Industrial rotameters are likely to be less accurate as these are 1-2% FS over a 10:1 range.
Flow rates can be manually set while tuning the valve opening and observing the scale. With small changes in viscosity, rotameters do not vary too much. This point depends on the equipment's design, as those that use ball measurements are the most sensitive, and larger ones are less sensitive. The viscosity limit is usually determined by the float shape and the material making up the rotameter. Once the instrument passes through its viscosity limit, the viscosity readings will need to be corrected.
If the fluid density is subject to change, one can use two floats. Of these two floats, one will depend on the fluid volume, and the other will correct the fluid density. Low-viscosity fluids such as gasoline, jet fuel, and other light hydrocarbons work best with mass flow rotameters. The float position can be changed after the density changes due to buoyancy, which is caused by matching the float density with the fluid density.
轉子流量計的安裝選項
Mounting Options of a Rotameter
轉子流量計必須垂直安裝,更寬端位于頂部。安裝轉子流量計的一些選項包括插入式、同軸法蘭式、同軸螺紋式和同軸夾具式。
安裝插入式流量計時,必須確保其垂直于流路。這些通常需要在工藝管道上有螺紋孔。在線法蘭流量計應與流動路徑平行,流動路徑必須位于兩個現(xiàn)有的法蘭過程管道之間。當內嵌螺紋流量計插入兩個已有的過程管道時,流路必須與內嵌螺紋流量計平行。在螺紋類型中,NPT 是最常見的。
Rotameters must be mounted vertically, with the widest end at the top. Some options for mounting rotameters are insertion, in-line flanged, in-line threaded, and in-line clamp.
When mounting insertion flow meters, one must ensure they are perpendicular to the flow path. These usually require a threaded hole in the process pipe. In-line flanged flow meters should be parallel to the path of flow, which must be between two existing pieces of flanged process pipes. The flow path must be parallel to the in-line thread flow meter as they are inserted into the two already-existing process pipes. Of the thread types, NPT is the most common.
轉子流量計的操作流程
Handling Process of a Rotameter
轉子流量計由玻璃制成,因此需要小心避免破裂。操作轉子流量計時,請勿將其設置為0,因為它會阻礙加壓空氣的流動并造成損壞。必須盡一切努力避免視差誤差;因此,為了看得清楚,可以使用酒精棉簽清潔玻璃外層。最后,浮子容易卡在流量計底座中,導致空氣堵塞而無輸出。將流量計倒置有助于嘗試將浮子從底座上移開。
A rotameter is made of glass, so care is required to avoid breaking it. When operating the rotameter, do not set it to 0, as it hinders the flow of the pressurized air and causes damage. Parallax error must be avoided by all means; therefore, to see properly, an alcohol swab may be used to clean the outer layer of the glass. Finally, the float tends to get stuck in the base of the flow meter, leading to blocked air and no output. Turning the flow meter upside down can be helpful in trying to move this float from the base.
第 2 章:轉子流量計的類型
Chapter 2: Types of Rotameters
轉子流量計可用于各種應用,每一種都有獨特的元素。轉子流量計的類型有玻璃管流量計、鎧裝吹掃流量計、法蘭鎧裝轉子流量計。下面將詳細解釋這些內容。
Rotameters can be used in various applications, and each one has unique elements. The types of rotameters include glass tube flow meters, armored purge meters, and flanged armored rotameters. These are explained in detail below.
玻璃管轉子流量計
Glass Tube Rotameters
玻璃管轉子流量計廣泛應用于工業(yè)領域、實驗室和其他中試工廠。硼硅酸鹽玻璃通常用于制造管子。為了抵抗腐蝕,浮子由不銹鋼、玻璃或塑料制成。由于其鋒利或計量邊緣,浮子反映了秤上的特定讀數。根據其使用領域,通常將連接件或端部配件放置在轉子流量計上。
Glass tube rotameters are extensively used in industrial areas, laboratories, and other pilot plants. Borosilicate glass is usually used to make the tube. To resist corrosion, the float is manufactured with stainless steel, glass, or plastic. The floats reflect a specific reading on the scale due to their sharp or metering edges. A connection or an end-fitting is usually placed on the rotameter in relation to its field of use.
標準化更重要的部分是管浮子組合,因為它執(zhí)行測量。查找表可以將提供的單位轉換為相關流體的流量。對于氮氣、氧氣、氫氣、氦氣、二氧化碳和氬氣等氣體,可以通過相關表檢查轉子流量計的相關刻度。這種方法更準確,因為在特定的溫度和壓力下已經確定了空氣或水的比例,但它可能不太方便。
可以使用許多不同的浮子來測量不同的流體流速。將玻璃管轉子流量計放置在視線水平位置可以使刻度讀數更容易記錄。玻璃管轉子流量計不能用于其他類型的流體,例如超過 194 °F (90 °C) 的水、高 pH 值流體以及會軟化管玻璃的濕蒸汽。玻璃也會被燒堿和氫氟酸溶解,因此必須使用其他管子。玻璃管轉子流量計的性能受到玻璃管壓力和溫度的限制,其中較高的溫度是主要限制因素。
玻璃管轉子流量計在混合或輸送多種氣體或液體流的區(qū)域中非常有效,盡管它們在一種流體流經多個通道的情況下也很有效。
The most important part of standardizing is the tube float combination since this carries out the measurements. Lookup tables can convert the provided units into flows of the relevant fluids. For gasses like nitrogen, oxygen, hydrogen, helium, carbon dioxide, and argon, the correlation scales of the rotameter can be checked with the correlation tables. This way is more accurate, as scales of air or water would have already been determined under specific temperatures and pressures, but it can be less convenient.
Different fluid flow rates can be measured using many different floats. Placing a glass tube rotameter at eye level can make the scale readings easier to record. Glass tube rotameters cannot be used for other types of fluids, such as water over 194 °F (90 °C), high pH fluids, and wet steam, which softens the glass of the tube. Glass is also dissolved by caustic soda and hydrofluoric acid, so other tubes must be used. The performance of a glass tube rotameter is limited by the limits in pressure and temperature of the glass tube, where higher temperatures are the major limiting factor.
Glass tube rotameters are effective in areas where several streams of gasses or liquids are mixed or transported, though they can also be effective where one fluid flows through several channels.
10A6130 玻璃管吹掃和低流量計
10A6130 Glass Tube Purge and Low Flow Meters
這更適合需要低流量的應用,包括吹掃控制管線和儀器外殼。該儀器更適合流體采樣、液位測量、液體比重以及氣體和液體的低流量使用。它由 (112, 3, 10”) 長度和 1/4” NPT 連接組成。
This is best for applications requiring a low flow rate, including purging control lines and instrument enclosures. This instrument is best for fluid sampling, level measurement, liquid specific gravity, and low-flow uses of gasses and liquids. It consists of lengths of (112, 3, 10”) with connections of 1/4” NPT.
10A4500 玻璃管流量計
10A4500 Glass Tube Flow Meters
它存在于大多數市政和工業(yè)設施中,用于測量液體和氣體。它作為烤箱和熔爐的一部分安裝,用于跟蹤天然氣流量,從而可以冷卻流體以保護設備。
This is found in most municipal and industrial facilities and is used to measure liquids and gasses. It is installed as part of ovens and furnaces to keep track of natural gas flow, thus making it possible to cool down fluids to protect equipment.
10A2235 玻璃管轉子流量計
10A2235 Glass Tube Rotameters
它用于在軸承潤滑劑流量過低時自動關閉重型設備。當冷卻水量低于一定限度時,它還會關閉電氣設備。
It is used to automatically turn off heavy equipment when the flow of the bearing lubricant gets too low. It also shuts down electrical equipment when water that is being cooled decreases below a certain limit.
鎧裝凈化流量計
Armored Purge Meters
這更適合市政和工業(yè)內低流量和高壓的區(qū)域。它還用于氣體分析儀系統(tǒng)以及出于安全考慮玻璃管不適合的地方。這些轉子流量計非常適合測量渾濁和不透明的介質。鎧裝凈化流量計的一個優(yōu)點是,如果系統(tǒng)狀況不佳,它可以凈化流體。 10A3200 是鎧裝吹掃流量計的一個示例,它具有 NPT 螺紋和針閥選項。
This is best for areas with low flow and high pressure within municipalities and industries. It is also used in gas analyzer systems and where glass tubes are unsuitable for safety concerns. These rotameters work well with measuring cloudy and opaque media. An advantage of an armored purge meter is that it purges the fluid if a system’s condition is not well. One example of an armored purge meter is the 10A3200, which is available with NPT threads and a needle valve option.
法蘭鎧裝轉子流量計
Flanged Armored Rotameters
這通常用于工業(yè)和其他專門從事制藥和石化產品的自動化系統(tǒng)。它可以測量強條件下的不透明流體和非導電流體。法蘭鎧裝轉子流量計最適合高壓用途。 FAM54 是法蘭鎧裝轉子流量計的一個示例,它包括法蘭連接。該轉子流量計的用途包括可選警報、HART 通信、累加器脈沖輸出、數字顯示器和發(fā)射器。
This is usually used in industries and other automated systems which specialize in pharmaceuticals and petrochemicals. It measures opaque fluids under forceful conditions and non-conductive fluids. A flanged armored rotameter is most suitable for high-pressure uses. An example of a flanged armored rotameter is the FAM54, which includes flanged connections. This rotameter’s uses include optional alarms, HART communications, totalizer pulse outputs, digital displays, and transmitters.
金屬管轉子流量計
Metal Tube Rotameters
金屬管浮子流量計具有由鋼制成的錐形管和由不銹鋼或聚四氟乙烯(PTFE)制成的浮子。 它們非常耐用、持久,具有卓越的強度,并且經過精心設計,適合測量高壓或高溫下的腐蝕性或渾濁液體。 金屬管轉子流量計具有防爆功能,具有高精度和可靠性,非常適合在惡劣、有壓力的條件下使用。
在金屬管浮子流量計中,磁性傳感器和芯片技術可產生流量、累積流量和百分比流量的 LCD 讀數。傳感器的磁耦合提供更穩(wěn)定的信號傳輸。
在非鐵磁金屬管轉子流量計中,浮子使用磁鐵,并在錐體外部安裝從動磁鐵來跟蹤浮子的位置。從動磁鐵機械連接到視覺指示器或讀出裝置。
A metal tube rotameter has a tapered tube made of steel and a float made of stainless steel or polytetrafluoroethylene (PTFE). They are highly durable and long-lasting, with exceptional strength, and are engineered to be suitable for measuring corrosive or turbid liquids from high pressure or temperatures. Metal tube rotameters are explosion-proof with high accuracy and dependability, making them ideal for use in harsh, stressful conditions.
In a metal tube rotameter, a magnetic sensor and chip technology produces an LCD readout of the flow, accumulated flow, and percentage flow. A magnetic couple of the sensor provides a more stable signal transmission.
In non-ferromagnetic metal tube rotameters, the float uses a magnet with a follower magnet mounted outside the cone to track the float's position. The follower magnet is mechanically connected to a visual indicator or readout device.
第 3 章:轉子流量計的應用和優(yōu)點
Chapter 3: Applications and Benefits of Rotameters
本章將討論轉子流量計的應用和優(yōu)點。
This chapter will discuss the applications and benefits of rotameters.
轉子流量計的應用
pplications of Rotameters
轉子流量計在市政和工業(yè)中用于精確的液位測量。它們用于凈化腐蝕性液體。轉子流量計測量和控制機械;例如,當冷卻機達到某個標記點時,它們可能會關閉冷卻機。它們也是需要持續(xù)潤滑的機械中的有效設備。
轉子流量計用作氣體分析儀,用于識別含有多種氣體的大氣中已知氣體的濃度。精確的密度轉子計也用于有效測量。工業(yè)現(xiàn)場的熔爐和煤氣燃燒器需要控制,以免損壞設備;因此,采用轉子流量計進行監(jiān)測。該設備還用于工業(yè)中的制冷流量控制。
Rotameters are used in municipalities and industries for accurate level measurements. They are used in the purging of corrosive fluids. Rotameters measure and control machinery; for example, they may shut down a cooling machine as it reaches a certain marked point. They are also effective equipment in machinery that requires continuous lubrication.
Rotameters are used as gas analyzers to identify the concentration of known gasses in an atmosphere that contains many. Accurate density rotameters are also used for effective measurement. Furnaces and gas burners in industrial sites need to be controlled not to damage equipment; therefore, rotameters are used for monitoring. This equipment is also used in industries for refrigeration flow control.
轉子流量計的優(yōu)點
Benefits of Rotameters
? 轉子流量計價格便宜且容易獲得。
? 轉子流量計可以測量具有小或中等速度的流體,例如1LPM至10LPM的速度。
? 金屬和玻璃轉子流量計蓋具有高度惰性,使其能夠抵抗化學反應。由于這種惰性,該設備非常適合與腐蝕性液體一起使用。
? 使用轉子流量計讀取讀數很簡單,因為它提供線性測量刻度,從而提供更高的精度和準確度。
? 轉子流量計不需要測量物質之外的任何外力,減少了讀數不準確的情況。
? 由于其小型設計,它們可用于廣泛的系統(tǒng)中。
? Rotameters are cheap and easily available.
? Rotameters can measure fluids with a small or medium velocity, e.g., a velocity of 1 LPM to 10 LPM.
? Metal and glass rotameter covers are highly inert, allowing them to resist chemical reactions. Due to this inertness, the equipment is good to use with corrosive fluids.
? Taking readings with a rotameter is simple as it provides a linear measurement scale, providing higher precision and accuracy.
? Rotameters do not require any external force outside the measuring substance, reducing inaccurate readings.
? Because of their small design, they can be used in a wide range of systems.
轉子流量計的缺點
盡管轉子流量計在某些領域很有用,但它們仍然有缺點。
? 在儀器運輸或維護過程中,隨著流體壓力隨時間增加,轉子流量計的外玻璃層很容易破裂。
? 由于難以看到計量浮子,因此很難使用不透明的流體進行測量。
? 如果用戶的眼睛沒有與測光浮標對齊,視差誤差可能會影響結果。測量時請保持儀器直立,避免傾斜,以免結果不準確。
? 分辨率比其他測量原理差。
? 轉子流量計不如其他儀器(如文丘里流量計或孔板流量計)堅固,因為它使用玻璃管。
? 轉子流量計對于測量波動的流體流量效果較差。
? 它們不適用于含有懸浮固體顆粒的液體。
? 轉子流量計的精度不如文丘里流量計或孔板流量計。
Drawbacks of Rotameters
Despite rotameters being useful in some areas, they still have drawbacks.
? A rotameter’s outer glass layer can easily break as the pressure in the fluid increases over time, while the instrument is in transport, or while it is being maintained.
? It can be hard to take measurements with non-transparent fluids because the metering float is difficult to see.
? If the user’s eyes are not aligned with the metering float, parallax errors may affect the results. Hold the instrument upright and avoid tilting to avoid inaccurate results during measurement.
? The resolution is poorer than other measurement principles.
? A rotameter is less sturdy than other instruments, like a Venturi meter or orifice meter, because it uses a glass tube.
? Rotameters are less effective for measuring fluctuating fluid flow rates.
? They are unsuitable for liquids with suspended solid particles.
? A rotameter is less accurate than a Venturi meter or orifice meter.
選擇轉子流量計時要考慮的因素
Factors to Consider When Choosing a Rotameter
? 流量——流量是選擇轉子流量計時要考慮的第一個參數。兩種類型的流量是液體體積流量和氣體體積流量。液體體積流量僅用于液體體積流量計。該速率表示為每單位時間體積流量的變化。同時,氣體體積流量僅適用于氣體體積流量傳感器,以單位時間內氣體體積的變化來表示。
? 工作壓力——工作壓力代表儀表能夠承受的介質總壓力。操作壓力很重要,因為它可以通過改變氣體密度來影響氣體。
? 流體溫度——襯里和結構材料的公差決定了可以使用的流體的溫度。
? 管道直徑——在安裝過程中,為了了解轉子流量計的正確尺寸,必須考慮管道直徑。
? 量表類型——必須標明量表類型,如百分位數,以幫助記錄。
? 閥門要求——針閥是最常用的。
? 在線法蘭流量計——用戶必須確保在線法蘭流量計與流動路徑平行,該流動路徑必須位于兩個現(xiàn)有的法蘭過程管道之間。
? 安裝儀表(侵入式與非侵入式) ——某些儀表,例如外部夾式流量計,不需要直接安裝到過程流上。這些被稱為非侵入式儀表,可用于封閉管道系統(tǒng)。
? 端部配件——端部配件可能包括壓縮配件,通過將套筒擰緊在接頭上來防止泄漏,或承插焊/活接頭(可以是焊頸)。
? 操作條件——轉子流量計具有最小和最大流量,具體取決于壓力和溫度。
? 所需的精度——必須了解使用設備所需的精度。
? 直觀的讀數——轉子流量計必須能夠提供直觀的讀數。
? 管道尺寸——每個轉子流量計都需要安裝在自己的管道內。
? 流量調節(jié)閥——流量調節(jié)閥是可選的,但它們的用途取決于轉子流量計的用途。
? Flow rate – Flow rate is the first parameter to consider when selecting a rotameter. Two types of flow rates are liquid volumetric flow rate and gas volumetric flow rate. Liquid volumetric flow rate is used only in liquid volumetric flow meters. This rate is expressed as the change in volume flow per unit of time. Meanwhile, gas volumetric flow rate only applies to gas volumetric flow sensors and is expressed in the change in gas volume per unit of time.
? Operating pressure – Operating pressure represents the total pressure of media that the meter can withstand. Operating pressure is important as it can affect gas by changing its density.
? Fluid temperature – The tolerance of the liner and construction materials determines the temperature of the fluid that can be used.
? Pipe diameter – The pipe diameter is important to consider during the installation process to understand the rotameter’s correct dimensions.
? Scale type – Scale types, like percentiles, must be indicated to help in record-taking.
? Valve requirements – The needle valve is the most commonly used.
? In-line flanged flow meters – Users must ensure in-line flanged flow meters are parallel to the path of flow, which must be between two existing pieces of flanged process pipes.
? Mounting meters (invasive vs. non-invasive) – Some meters, e.g. external clamp-on flow meters, don’t need to be mounted directly to the process flow. These are called non-invasive meters and can be used in closed piping systems.
? End fittings – End fittings may include compression fittings, which prevent leakage by tightening down a sleeve over a joint, or a socket weld/union, which can be a weld neck.
? Operating conditions – Rotameters have minimum and maximum flow rates depending on the pressure and temperature.
? Needed accuracy – One must understand the accuracy needed in using the equipment.
? Straightforward readings – A rotameter must be able to provide straightforward readings.
? Pipe size – Each rotameter needs to fit inside its own pipe.
? Flow regulation valves – Flow regulation valves are optional, but they can be useful depending on the use of the rotameter.
結論
Conclusion
轉子流量計,也稱為變面積流量計,是用于測量液體或氣體通過錐形管時液體或氣體體積流量的儀器。當需要將成本保持在最低并且不需要高精度時,最好考慮轉子流量計。
Rotameters, also known as variable area flow meters, are instruments used to measure the liquid or gas volumetric flow rate as either a liquid or gas passes through a tapered tube. The rotameter is best considered when the cost is to be kept at a minimum and when high accuracy is not required.
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