Falling sphere viscometer artur balthazar cole garcia mashal alhader thomas gaede september, 2015 1. Homework statement a falling sphere viscometer measures the viscosity of a liquid from the terminal velocity of a tiny, falling sphere. Problems measuring viscosity of water with a falling ball. Pdf development of lowcost visionbased falling sphere viscometer. If measurements on for a given test liquid could be restricted to low reynolds number regime covered. Falling sphere viscometer definition of falling sphere. Pdf a commonly used apparatus in undergraduate physics laboratory environment is the falling sphere viscometer or stokes viscometer. It is assumed that the dimensions of the capillary tube play a key role in the function of the viscometer.
For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Hold one sphere, with the help of pillers, approximate 25 mm lower the glycerol surface in the cent er of the cylinder. Mar 07, 2014 falling sphere viscometer a viscometer is an instrument used to measure the viscosity of a fluid. K s f t, where l g d k 18 2 3 here, l is the falling length, and t is the time passing the length of l. A falling ball viscometer has a sphere ball that falls down along a tube containing the sample liquid to be measured, and this tube is surrounded concentrically by a tubular jacket for thermal control. Stokes law is the basis of the falling sphere viscometer, in which the fluid is stationary in a vertical glass tube. Pdf on sep 1, 2017, riady siswoyo jo and others published development of lowcost visionbased falling sphere viscometer find, read. Falling ball viscometer principle instrumentation tools. Stokes law can be used to calculate the viscosity of the fluid. Target customers oil industry, petrol industry, inks and solvents, paint, food, detergents, cosmetic, pharma and chemical industries low budget and entry level customers. A sphere of known density and diameter is dropped into a large reservoir of the unknown fluid. The amount of time it takes from release to a specific point in a cylinder gives you a measure of resistance that is the fluid viscosity. Rotational viscometer alpha series allows fast and accurate viscosity readings. This viscometer makes use of the principles in case of flow around a small sphere.
Brookfield viscometers rheometers falling ball viscometer. Pdf design of a high precision falling ball viscometer. Viscosity is determined by timing how long it takes the cup to empty, and is measured in cup seconds. Haake viscometer standard operating procedure updated.
Design of a high precision falling ball viscometer archive ouverte. Falling object sphere or piston viscometer put simply, a piston, or sphere, of known size and density, is lifted and then released into a fluid. Viscosity coefficient is one of the important properties of liquid. A coaxial cylinder type rotational viscometer design and optimization md rasedul islam, md mahbubur rahman, shamim ahmed and mihir ranjan halder abstractthe history of viscosity measurements is outspread and is believed to date back to when people began measuring the. A falling ball viscometer is described requiring a sample volume less than 1 ml. The viscometer includes a test certificate with data values for sphere constant k and density. The most common types of viscometer are capillary, rotary, falling sphere, and ultrasonic. A coaxial cylinder type rotational viscometer design and. Fill the bath of the circulating thermostat with r fig. Viscosity and viscoelastic behavior of resins are very critical in. Yes, it applies when the reynolds number is very low.
I am measuring the viscosity in water using a falling ball viscometer. Turn the viscometer to normal position and wipe tube a clean. The measurement of viscosity then rests on the speed limit measurement of falling ball, corrected principal identified effects edge effects, inertial. Photoelectric read out allows for a fast and simple measurement procedure. In a fallingball viscometer, a steel ball with a diameter of 0. This field is represented with orange arrows in the drawing. Find out information about fallingsphere viscometer. Quality control of a milk processing system such as the one shown below would rely on such viscosity measurements. Viscosity measurements with the falling ball viscometer. Viscosity of newtonian fluids using haake falling ball viscometer duration.
I just dont know why our professor asked us to get the ratio of the spherical metal balls diameter and the diameter of the falling sphere viscometer and plot the velocity of the spherical metal ball vs. Typically, the viscosity of the fluid will be on the order of 100s to s of poise, and the ball will only be on the order of a few mm. Falling speed of a 2 mm ceramics ball in a 350oil batch 2 at 19. The forces acting on a sphere falling in a falling ball viscometer consist of force due to gravity f g, force due to the buoyancy of the solution f b, and force due to drag on the ball from the liquid f d. A constructed inductor coil for the purpose of metal detection. A fluid analysis was done to determine how the dimensions of the viscometer affected its function.
A modification of the straight falling sphere viscometer is a rollingball viscometer, which times a ball rolling down a slope whilst immersed in the test fluid. Measurement of viscosity in a vertical falling ball viscometer. Glass capillary viscometers gost allunion state standard 1002867. Insert the horizontal rod of the viscometer e into the nut f. The electromagnetic spinning sphere viscometer is equipped with two magnets attached to a rotor which create a rotating magnetic field. Dont let traditional viscometers get in the way of perfect. Pdf data acquisition system for a fallingsphere viscometer. The falling sphere viscometer allows the user to determine the viscosity of the sample by timing the time it takes for a metal ball to travel 100mm between two calibrated lines. This would necessitate using a large quantity of the test fluid. Ng sphere viscometer case of a sphere approaching an infinite rigid plane such as the bottom of the containing vessel of a falling sphere visco. The falling ball viscometer uses the simple, but precise, hoppler principle to measure the viscosity newtonian fluids by measuring the time required for a ball to fall under gravity through a samplefilled tube. The forces acting on a sphere falling in a falling ball viscometer consist of force due to gravity f g, force due to the buoyancy of the solution f. All of these accessories are interchangeable with the frv101 and the laray unit.
The viscometer used consists of a cylindrical cup with a capillary tube at one end. Bubble viscometers measure the amount of time it takes a bubble of gas to move through the material whose viscosity is being tested. The hoppler principle is used to measure the viscosity of newtonian liquid by measuring the time required for a ball to fall under. The principle of the viscometer is to determine the falling time of a ball of. Jul 20, 2007 we had a experiment on a metal ball dropped on a falling sphere viscometer containing a certain liquidi forgot what was it. Measurement of viscosity in a vertical falling ball. The falling ball viscometer is based on stokes law. An orifice viscometer usually consists of a cup with a hole, through which the fluid flows. Specific examples include liquid hydrocarbons, sugar solutions, solvents, and polymer solutions.
Described herein is a falling piston viscometer which includes a measuring bushing and a piston configured to be slidably receivable inside the measuring bushing. The falling ball viscometer corresponds to the requirements of many international standards, i. Falling sphere viscometer with 6 spheres and 1 ball gauge thermometer 0 100 c cleaning set test certificate with accurate values for sphere constant k and density for converting duration of fall to actual viscosity. A falling sphere viscometer measures viscosity by capturing the time it takes for a sphere of a known dimension and density to make its. The falling ball viscometer is based on the measuring principle by hoppler for simple but precise dynamic viscosity measurement of transparent newtonian fluids. The sample 3 to be measured is in a small test tube 2 with a smooth concave bottom. Working together with your frv2000 or laray style viscometer, this semi automatic viscometer technology offers a great deal of in depth research capabilities both formally and easily. Measurement of terminal velocity of a ball falling in a viscous fluid enclosed in a narrow tube provides a method for determination of the coefficient of viscosity. At steady state, the viscous drag and buoyant force of the sphere is balanced by the gravitational force.
Dont let traditional viscometers get in the way of. If correctly selected, it reaches terminal velocity, which can be measured by the time it takes to pass two marks on the tube. Apparatus figure 1 is a schematic of a falling ball viscometer. Aml instruments supplies a complete line of accessories for the kershaw falling rod viscometer including. Apr 27, 2015 falling sphere viscometer the falling ball viscometer is based on stokes law. Start stop watch when the ball reaches to the first marks on the tube, and measure the time between the two marks. Since the sphere is falling with constant velocity there is a.
The subscript s and f represent the sphere and fluid, respectively. Kershaw instrumentation llc falling rod viscometer. Absolute falling ball viscometer, adapted to the low viscosities of. Falling body viscometers are commonly used for lowviscosity substances in the pharmaceutical, food, chemical and mineral oil industries.
Introduction the objective of this experiment is to. Fallingsphere viscometer article about fallingsphere. Before starting the measurement, it is better to turn the falling tube up and down at least once in order to enhance temperature uniformity along the tube. This can be further improved by using a patented v plate, which increases the number of rotations to distance traveled, allowing smaller, more portable devices. Poulten selfe viscometer falling sphere viscometer falling. The basic concept is to measure the elapsed time required for the ball to fall under gravity through a samplefilled tube inclined at an angle. Haake viscometer standard operating procedure updated sept 10, 2014 general information viscosity is a measure of the resistatnce of a fluid which is being deformed by either shear stress of tensile stress. Find out information about falling sphere viscometer. Instruction manual falling ball viscometer c part no.
It measures the time a ball takes to move through the sample liquid. A falling sphere viscometer available in an undergraduate physics laboratory. The previous theory used newtons law of motion for describing the falling ball reaching a terminal velocity. How do i calculate viscosity with falling sphere viscometer. Falling sphere viscometer another method of measuring the viscosity of a fluid is the rotating viscometer figure 4. Fallingball viscometer hoeppler manual anton paar wiki.
Insert the viscometer into a holder and place in constant temperature bath. Nov 16, 2012 a standard viscometer for very viscous fluids is the falling ball viscometer. Falling ball viscometer experiment viscosity measurement b. Falling sphere viscometer article about falling sphere. One such device determines that a tiny sphere of radius 46.
The lack of information on as a function of reynolds number over the whole range is the only limiting factor in the use of falling ball viscometry to determination of absolute value of. Kershaw instrumentation llc falling rod viscometer, model. In practice therefore, it is common to use a hoppler falling sphere viscometer, which uses a cylinder inclined to the vertical, such that the sphere descends by rolling and slipping down the side of the tube. In the falling ball viscometer, a spherical steel ball is allowed to fall through a tube containing the solution to be measured. Falling sphere 40mm falling sphere glass viscometers. Falling sphere viscometer department mechanical engineering.
Moreover, viscosity and terminal velocity of a falling ball can be determine by fallingsphere viscometer using laser system which have done by,getachew work. The falling ball viscometer utilizes the simple but precise hoppler principle to measure viscosity. The brookfield falling ball viscometer measures viscosity in accordance with the test method defined in din 53015 hoppler principle to measure the viscosity of newtonian liquid by measuring the time required for a ball to fall under gravity through a samplefilled tube. M 1 and m 2 in the vnzh, also m 3 are markings for measurement of the time of discharge of fluid from the measuring reservoirs or the time for filling the. Normally, the measurement accuracy of the falling ball method is not high by using a manual stopwatch considering the existing parallax errors of the sphere.
This tube carries two ring marks a and b, which are spaced 100 mm apart and which limit. Falling ball viscometer aim the purpose of this experiment is to measure the viscosity of unknown oil with a falling ball viscometer. A viscometer which measures the speed of a spherical body falling with constant velocity in the fluid whose viscosity is to be determined. Principle the principle of the viscometer is to determine the falling time of a sphere with known density and diameter within a fluid filled inside glass tube. Measure the time with the help of stop watch that sphere takes to fall 305 mm as marked by the pieces of masking tape. Falling ball viscometer is a well developed device for measuring viscosity of a fluid, and the method had claimed in international standards 4, 5. This type of viscometer consists of a circular cylinder filled by the liquid under investigation. The friction or the deformation drag f d of the sphere moving at a constant velocity v through a fluid of infinite extend is. Borosilicate glass 40mm diameter fall tube, graduated at six points, fitted by means of a 2429 joint with a stopper having a sphere release tube with 5mm bore, funnel top and small vent hole. Stokes law, reynolds number, and measuring liquid viscosity. To obtain viscosity values, a calibration with a viscosity reference standard and the samples density are required. Viscometers visual encyclopedia of chemical engineering.
Instrumentation electronics devices and applications. Falling rod viscometer data sheet frv2000 data sheet. The viscometer is meant to approximate an infinitely long column of infinite diameter. Fluids lab report 1 experiment no 1 falling sphere. Falling sphere viscometer the falling ball viscometer is based on stokes law.
The classic falling ball viscometer works according to the hoeppler principle. The circumferential edge of a first section of the piston in the described falling piston assembly is. The determination of viscosity with a capillary viscometer is based on poiseuilles law and. Immediately remove the shafts plastic protector before beginning to use the viscometer. Several studies on the falling ball viscometers were conducted with newtonian fluids3, and wealthy fluids in suspended particles 4. The force difference between the weight and buoyancy of the sphere.
R viscosity measurements with the falling ball viscometer 1. A new method of accurate calculation of the coefficient of viscosity of a test liquid from experimentally measured terminal velocity of a ball falling in the test liquid. A sphere of known size and density is allowed to descend through the liquid. Orifice viscometers are easy to use manually, thanks to the fact that theyre simply dipped into the fluid being worked with making them popular. Falling sphere viscometer synonyms, falling sphere viscometer pronunciation, falling sphere viscometer translation, english dictionary definition of falling sphere viscometer. Description for transparent liquids of high viscosity possessing newtonian flow characteristics. This falling sphere viscometer is suitable for testing a variety of fluids, such as oils, gases, polymers, cosmetics, detergents, and foods for use in a variety of industries. Measure viscosity precisely using only a stop watch and no power connection with the thermo scientific haake falling ball viscometer c. We used a 25 ml burette and 38inch chrome steel bearing balls ball bearings to test three liquids. A viscometer also called viscosimeter is an instrument used to measure the viscosity of a fluid. The measuring accuracy of the haake falling ball viscometer c is among the highest available in any type of viscometer, particularly when supported with the precise temperature control of a circulator.
Stokes law is a proposition that relates the drag force experienced by a falling sphere to the sphere s constant velocity in a liquid of known viscosity. Falling sphere viscometer u14260 mechanics of gasss. Aug 23, 20 viscosity of newtonian fluids using haake falling ball viscometer duration. A standard ball is allowed to fall down this tube over a calibrated distance of 100 mm. Viscometer uses the simple but precise hoppler principle to measure the viscosity of newtonian liquids by measuring the time. The crosssection of the viscometer is shown in figure 1.
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