G.H.PATEL COLLEGE OF ENGINEERING AND TECHNOLOGY Subject – fluid flow operation Code – 2130502 Chemical engineering department

Prepared by :- GUIDANCE BY :- Dr. M.S.BHAKHAR AND Mr. VINAY B. PATEL KUNDNIKA PATEL [130110105028] KUNJAN PATEL [130110105029] MITESH V. PATEL [130110105030] GUIDANCE BY :- Dr. M.S.BHAKHAR AND Mr. VINAY B. PATEL

-: CONTENT :- EXPLANATION OF ROTAMETER PRINCIPLE OF ROTAMETER MAIN FEATURES OF ROTAMETER TYPES OF ROTAMETER FLOW MEASURMENT USING BERNOULLI’S THEOREM SIZING OF ROTAMETER ADVANTAGES TYPES &APPLICATIONS

EXPLANATION OF ROTAMETER A rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through, to vary, causing a measurable effect. A rotameter consists of a tapered tube, typically made of glass with a 'float', actually a shaped weight, inside that is pushed up by the drag force of the flow and pulled down by gravity. The drag force for a given fluid and float cross section is a function of flow speed squared only, see drag equation.

A higher volumetric flow rate through a given area increases flow speed and drag force, so the float will be pushed upwards. However, as the inside of the rotameter is cone shaped (widens), the area around the float through which the medium flows increases, the flow speed and drag force decrease until there is mechanical equilibrium with the float's weight. Floats are made in many different shapes, with spheres and ellipsoids being the most common. The float may be diagonally grooved and partially colored so that it rotates axially as the fluid passes. Readings are usually taken at the top of the widest part of the float; the center for an ellipsoid, or the top for a cylinder.

The "float" must not float in the fluid: it has to have a higher density than the fluid, otherwise it will float to the top even if there is no flow. The mechanical nature of the measuring principle provides a flow measurement device that does not require any electrical power. If the tube is made of metal, the float position is transferred to an external indicator via a magnetic coupling. This capability has considerably expanded the range of applications for the variable area flowmeter, since the measurement can observed remotely from the process or used for automatic control.

FIGURES OF ROTAMETERS

Principle of Rotameter (Flow meter) When fluid or gas flows through a taper tube containing a float, a pressure difference of P1 and P2 is created between upper and lower side of the float. The float moves upwards by a force obtained by the pressure differential by the maximum cross sectional area of the float. Due to taper tube, as the float moves upwards, the fluid passing area increases as a result of which the differential pressure decreases. Upward movement of float stops when the dead load is dynamically balanced by the differential pressure. Tapering of metering tube is so designed that the vertical movement of the float becomes linearly proportional to the rate of flow and the scale is provided to read the position of the float.

main features: type of rotameters : The height of the float indicates flow rate The rotameter tube can be calibrated and graduated in suitable flow units Rotameter tubes can be made from glass, metal, or plastic Tube diameters range from 1/4 to greater than 6” Glass or metal tubes are used depending on application need & safety Plastic-tube rotameters are low cost rotameters. They are perfect for applications involving corrosive fluids or deionized water Almost all rotameters are insensitive to viscosity variations One of the early float designs had slots, which caused the float to spin for stabilizing & centering purposes. Because of this rotation, the term rotameter was coined type of rotameters : 1) Glass tube rotameter 2) Magnetic rotameter

1) Glass Tube Rotameter: Main components are tube & float. The basic rotameter is the glass tube indicating-type. The tube is precision formed of borosilicate glass, and the float is precisely machined from metal, glass or plastic. The metal float is made of stainless steel (for corrosion resistance). The float has a sharp metering edge where the reading is observed by a scale mounted along tubeside. The scale of the rotameter can be calibrated for direct reading of gases & liquid. It can read percent or arbitrary number. Glass tube rotameters are not suitable for water with high pH, wet steam, caustic soda and hydrofluoric acid. Measuring range : Small 6 mm (1/4") tubes are suitable for working pressures up to 500 psig, operating pressure for a large 51 mm (2") tube is as low as 100 psig. Temperature limit is 204°C. There is a linear relationship between the operating temperature and pressure.

2) Magnetic Rotameter: These Rotameters are intended for application where high pressure, temperature OR corrosive conditions. Thus metal variable area type flowmeter is designed to measure flow rate of liquids, gases & steam under critical conditions. It consists of a tapered metal tube, an indicating assembly and a float. A magnet encapsuled in float couples with rotating magnets connected to an indicating pointer, thus the movement of the float, is accurately indicated in terms of flow rate. magnetic floats can be used for alarm and signal transmission functions.

FLOW MEASUREMENT USING Bernoulli's theorem When fluid or gas flows through a taper tube containing a float, a pressure difference of P1 and P2 is created between upper and lower side of the float. The float moves upwards by a force obtained by multiplying the pressure differential by the maximum cross sectional area of the float. Due to taper tube, as the float moves upwards, the fluid passing area increases as a result of which the differential pressure decreases. Upward movement of float stops when the dead load is dynamically balanced by the differential pressure. Tapering of metering tube is so designed that the vertical movement of the float becomes linearly proportional to the rate of flow and the scale is provided to read the position of the float, thus giving birth to flow rate indication. Based on Bemoulli's theorem, the principle mentioned above can be theoretically expressed as follows. FLOW MEASUREMENT USING Bernoulli's theorem Where •  Q = Volumetric flow rate •  V = Volume of Float •  C = Flow coefficient •  Af = Maximum pressure receiving area of float. •  A = Fluid passing Area •  P = Float Density •  g = gravimetric acceleration •  y = Fluid Density

Major advantages of Rotameter : Sizing of Rotameter Rotameters are generally provided with calibration data and a direct reading scale for air or water. For sizing a rotameter for other service, it is necessary to first change the actual flow to a standard flow. In case of liquids the standard flow is meant to be the water equivalent in GPM whereas when gases are concerned, the intended standard flow is the air flow equivalent in standard cubic feet per minute. Tables listing standard water equivalent gpm and air scfm values are supplied by rotameter manufacturers. It is required to mention slide rules, nomographs, or computer software which is often needed for sizing of rotameter. Major advantages of Rotameter : Low cost Simplicity Low pressure drop Quite wide rangeability Linear output

TYPES & APPLICATION OF ROTAMETER ROTAMETER FLOW METER , F VA Trogfluk :- Low Cost Plastic Rotameter / Variable Area Flow Meter for Water & Transparent Liquids, Air & Gases . General purpose plastic rotameter / VA flow meter from for non-demanding liquid or gas flow applications. The F VA Trogflux rotameter flow meter is available in standard or short tube lengths FOB PRICE :- 15 US $

2) ROTAMETER FLOW METER , F VA Tubux :- The Mecon F VA Tubux is a variable area flow meter with a glass flow tube for measuring the volume of transparent liquids and gases (e.g. air, nitrogen, hydrogen, oxygen, argon, helium) passing through closed piping. 3) ROTAMETER FLOW METER , F VA UNOX :- Variable Area Flow Meter with Removable Glass Flow Tube for Water, Liquids, Air & Gases and High Temperature Applications . Rotameter / VA flow meter with a glass flow tube from Mecon GmbH that is compatible with many chemical substances and can withstand temperatures up to 150 deg C. FOB PRICE :- 09 US $ FOB PRICE :- 27 US $

4) ROTAMETER FLOW METER , F VA MINIX :- Aluminium Rotameter with Glass Flow Tube and Built-in Needle Valve for Manual Control of Flow Rates . The Mecon F VA Minix aluminium variable area flow meters with glass flow tube are used to measure the volume of transparent liquids and gases passing through closed piping.  The built-in needle valve permits manual control of flow rates FOB PRICE :- 43 US $

5) ROTAMETER FLOW METER , F VA 250 :- All Metal Rotameter / Variable Area Flow Meter for Rugged Environments, High Temperatures & Pressures . The Mecon F VA 250 is an all- metal variable area flow meter for liquids and gases up to 300 deg C.  With a standard length of 250 mm and a completely metal design the F VA 250 rotameter can be used to measure many different types of liquids and gases passing through closed piping FOB PRICE :- 22 US $

-: REFERENCES :- http://www.alibaba.com/product-detail/DF4500-Compressed-air- application-of-rotameter_1355078064.html?s=p http://www.icenta.co.uk/flow/Variable-Area-Flow-Meters-&-Rotameters http://en.wikipedia.org/wiki/Rotameter www.keyinstruments.com/index.php/custom.../rotameter-manufacturer www.omega.com/prodinfo/rotameters.htmL