NEWS

Products

Contact us

Yuyao Yinhuan Flowmeters Ltd.

Phone:+86 574 62689077

Fax:+86 574 62689088

Address:Northeast China Yuyao City in Zhejiang

Rainbow Road on the 1st Industrial Park

Zip Code:315400

Principle rotameter

You are here: HOME >> News >> Technical Articles

Principle rotameter

Release date:2014-08-14 00:00 Source:http://www.yinhuanchina.com Click:

 

Flow rate detection element rotameter principle is made under a self-expanding tube and a tapered vertical upward movement along the axis of the cone at the group consisting float. How it works: the measured fluid from the bottom up through the annulus of the cone 1 and 2 are formed of 3:00 float float float upper and lower ends are formed to produce a differential pressure rising force, suffered when the float rises immersed in a fluid force is greater than the float weight, The float will rise, annulus area increases, the annulus of the fluid flow rate drops immediately float up and down the lower end of the differential pressure acting on the float also rises with the reduction in force until the lifting force equal to the weight of the float is immersed in a fluid, The float will be stabilized at a certain height. Float in the tapered tube has a height and flow through correspondence. 2. Introduction caliber 15-40mm transparent tapered tube rotameter typical structure shown in Figure 2. Transparent conical tube 4 most commonly used is made of borosilicate glass, glass rotameter referred habit. Traffic indexing directly engraved on the outer wall of the cone 4, but also in the other side of the cone mounted indexing ruler. Cone tube lumen has a smooth surface and a cone with a guide edge ribs (or plane) two. Float freely move within the cone, or to move the cone edge reinforcement guided, large mouth smooth surface inner wall of instruments are used by the guide rod guide. Right Angle Mounting metal tube typical structure, usually applied to more than 15-40mm caliber instrument. Tapered tube and float 4 5 flow rate detection element composition.


    The inner sleeve has a guide rod extending section 3, by magnet coupling, etc., will be passed to convert part of the displacement of the float outside the casing. Converting part of a local indication and remote signal output two types. In addition to the right-angle mounting structure as well as import and export center line and taper pipe concentric through-type structure, usually less than for 10-15mm diameter instrument. 3 features rotameter for use in small diameter and low flow rates. Common meter diameter 40-50mm below the minimum diameter do 1.5-4mm. Suitable for measuring low flow low flow, liquid, for example, the following caliber 10mm diameter glass tube rotameter nominal full-scale flow, flow only between 0.2-0.6m / s, or even less than 0.1m / s; metal tube float flowmeter and caliber larger than 15mm of glass rotameter slightly higher flow rate between 0.5-1.5m / s. Rotameter can be used for low Reynolds numbers, the selection of viscosity insensitive to the shape of the float, as long as the flow of the annulus at the Reynolds number is greater than 40 or 500, Reynolds number flow coefficient that is kept constant, that is fluid viscosity changes do not affect the flow coefficient. This value is far below the standard orifice plate throttling differential pressure meter minimum Reynolds number of requirements 104-105. Most rotameter no upstream straight pipe requirements, or that the upstream straight pipe less demanding. Rotameter has a wide range of flow rate, typically 10: 1, a minimum of 5: 1 up to 25: 1. Output flow sensing element close to linear. A low pressure loss. Simple glass rotameter structure and low prices. As long as the person at the scene indicates the flow easy to use, the disadvantage is the risk of glass fragile, especially non-oriented structure of the float for gas. Metal tube without risk taper pipe rupture. Compared with glass rotameter, wide temperature and pressure range. Most of the structure can be used only rotameter pipe installation from the bottom up vertical flow. Rotameter application limited to small diameter, general full flow type rotameter not be used for large diameter glass tube rotameter largest diameter 100mm, metal tube 150mm, larger diameter can only shunt type instrument . Fluid and factory calibration fluid is not the same, to make the flow value correction. Liquid water is usually used rotameter calibration, the calibration gas with air, such as the actual use of the fluid density, viscosity contrast, traffic to deviate from the original scale value, to be converted amended. 4. Technical parameters Measuring range: water (20 ℃) 1-200000 l / h of air (20 ℃, 0.1013MPa) 0.03-4000m3 / h see flow meter, flow can be special ordered turndown ratio: the standard 10: 1 special type 20: 1 Accuracy: Standard Special version 1.0 1.5 Pressure Level: Standard: DN15-DN50 4.0MPa DN80-DN200 1.6MPa special type: DN15-DN50 25MPa DN80-DN200 16MPa pressure rating is 1.6MPa jacket special type Before the selection and ordering the pressure loss should consult with the factory: 7kPa-70kPa medium temperature: Standard: -80 ℃ - + 200 ℃: PTFE: 0 ℃ -85 ℃ high temperature: up to 400 ℃ Medium viscosity: DN15: <5mPa.s (F15.1-F15.3) <30mPa.s (F15.4-F15.8) DN25: <250mPFa.s DN50-DN150: <300mPa.s ambient temperature: the liquid crystal type -30 ℃ - + pointer 85 ℃ -40 ℃ - + 120 ℃ Connection: Standard: DIN2501 standard flange special type: specified by the user of any standard flange or threaded cable connections: M20 * 1.5 Power supply: Standard: 24VDC wire 4 -20mA (10.8VDC-36VDC) Alarm output: upper or lower instantaneous flow alarm, open collector output (max 100mA @ 30VDC internal impedance of 100 ohms) relay output (contact capacity 1A @ 30VDC or 0.25A@250VAC or 0.5A @ 125VAC) Pulse output: Cumulative pulse output, a minimum interval of 50 ms LCD: instantaneous flow rate display Value range: 0-50000 Cumulative flow display Value range: 0 to 99999999 (available with a decimal point) Protection: IP65 Explosion-proof mark: intrinsically safe iaⅡCT5 ; flameproof dⅡBT6 5, precautions meter installation direction most of the rotameter must be installed vertically on a vibration-free pipeline, we should not have a significant tilt, bottom-up flow of fluid through the meter. Said that for the pipe connection example, is equipped with a bypass pipe so that the continuous flow system for maintenance. Rotameter between the centerline of the angle between the plumb line and generally not more than 5 degrees, high accuracy (above 1.5) meter θ≤20 °. If θ = 12 ° will produce a 1% additional error. Gauges No strict upstream straight pipe length requirements, but there are also required by the manufacturer (2-5) D length actually not necessity. Installation for fouling fluids should be installed upstream of the meter filter. Metal tube float flowmeter coupled with a magnetic iron magnetic impurities fluid when possible, should be installed before the meter magnetic filter. To keep the float and tapered tube cleaning, particularly small-caliber instruments, float significantly affect the cleanliness of the measured values. 6mm diameter glass rotameter for example, in laboratory measurements seemingly clean water flow rate of 2.5L / h, run after 24h, a few percent increase flow indication, the float surface contaminated with the naked eye no foreign body, remove the float Wipe with gauze, namely to restore the original flow indication. If necessary, rinse the pipe as shown in diagram set to periodically flush.


 Installation pulsating flow

   Pulsating flow itself, such as the upper reaches of the proposed location have mounted instrument reciprocating pumps or valves, or downstream of a large load changes, etc., should be replaced to remedy or improve the measurement position in the piping system, such as the installation of a buffer tank; if the meter itself oscillation such as when measuring gas pressure is too low, the meter upstream valve is not fully open, the control valve is not installed in the downstream of the meter and other reasons, it should be targeted to improve to overcome, or to change the damping device chosen instrument. Installation to expand the scope of the measurement requirements if the width of the flow range, range of more than 10, often used in parallel tube rotameter flow range of 2 different units or more, according to the measuring instrument choose one or more series, small read the flow meter indicates a value lower flow range, high flow meter reads a value representing large flow, series parallel method is easier than law, need not frequent opening and closing the valve, but the pressure loss is large. You can also put an instrument in two different shape and weight of the float, take frivolous child reading a small flow, float to the top of the float after taking weight readings can be expanded to 50-100 degree range. To drain the liquid gas import and export with the instrument is not in line angle metal rotameter, note whether the rumor residual air within the float casing extended displacement must be drained for liquids; prone to accumulate if the liquid contains tiny bubbles flow in the casing, but it should be regularly vented. This is even more important for small caliber instrument, or affect the flow indication obvious. Flow rate as necessary if not by media conversion parameters density, viscosity and other instruments tailored to the manufacturer, the liquid is usually calibrated flow of water, gas meter by meter calibration air, value engineering standard condition. Conditions of fluid density, temperature and calibration gas pressure is inconsistent, to do the necessary conversion. Conversion formulas and methods of the manufacturer instruction manual has described in detail.


Calibration and calibration rotameter

    Rotameter calibration and calibration liquid commonly used standard table method, volumetric method and weighing method; gas commonly used method bell, a small flow with soap membrane. Some foreign manufacturers of bulk products has been able to dry calibration that controls the size of the tapered tube and float weight size, indirectly determine the flow rate value, in order to reduce cost, precision instrumentation was sitting only actual flow calibration. There are also some manufacturers strictly control the inner diameter of the tapered tube and taper starting point and the size of the float, real flow calibration checks only play within the tapered tube surface quality. Such factory production instruments, tapered tube and float have been made interchangeable, no need to replace the complete set. Rotameter calibration standard table method is an efficient method, with the application of each manufacturer. Some factories will be a flow range of the standard table made of several smaller segments taper glass tube rotameter, extend the length of the standard meter rear sight and improve the accuracy of standard tables, so check the calibration precision and high efficiency of work to do. Metal tube for small caliber and low velocity medium flow measurement; reliable, low maintenance, long life; do not ask for straight sections; wide flow ratio of 10: 1; two-line large LCD, optional site instantaneous / accumulated flow display, backlit uniaxial sensitive indicator; non-contact magnetic coupling drive; all-metal structure, suitable for high temperature, high pressure and corrosive media; can be used for flammable and explosive hazardous locations; optional two-wire system , battery, AC power supply; multi-parameter calibration function; with data recovery, data backup and power-down protection.


Related Tags:Glassrotameter

S
e
r
v
i
c
e
二维码

Scanning

分享
Welcome to our message
Please enter the message content here!
Full name
Contacts
Phone
Mobile Phone