TILI Automation

 Due to humidity, several materials experience a change in physical, chemical and electrical properties. This property is used in transducer that are designed and calibrated to read relative humidity directly. Hair hydrometer is a type of absorption hydrometer and uses the mechanical humidity sensing technique. Certain hygroscopic materials such as human hair, animal membranes, wood, paper, etc., undergo changes in linear dimensions when they absorb moisture from their surrounding air. This change in linear dimension is used as the measurement of humidity present in air. Description of Hair Hydrometer The main Parts of hair hydrometer are, Human hair is used as the humidity sensor. The hair is arranged in parallel beam and they are separated from one another to expose them to the surrounding air/atmosphere. Number of hairs are placed in parallel to increase mechanical strength. This hair arrangement is placed under small tension by the use of a tension spring to ensure proper funct...

 A change in resistance with change in humidity is taken as a measure of humidity. This is type of Electrical Humidity sensing Absorption Hydrometer, know more about mechanical humidity sensing methods using Hair Haydrometer. Description: The main Parts of this arrangements are, two metal electrodes which are coated and separated by a humidity sensing hygroscopic salt (lithium chloride). The leads of the electrodes are connected to a null – balance wheat stone bridge. Operation: When the humidity of the atmosphere is to be measured, the electrodes coated with lithium chloride are exposed to atmosphere. Humidity variation causes the resistance of the chemical (lithium chloride) to change. That is, the chemical absorbs moisture or loss moisture and causes a change in resistance. Higher the humidity (RH) in the atmosphere more will be the humidity absorbed by lithium chloride and lower will be the resistance. Lesser the humidity (RH) in the atmosphere less will be the humidity absorbe...

 Sling Psychrometer is used to measure both the dry bulb and wet bulb temperatures at time. These temperatures are a measure of humidity content in air. Description of Sling Psychrometer The main parts of the instrument are The instrument frame which holds the thermometers. One mercury in glass thermometer whose sensing bulb is bare to directly contact the air and to measure the temperature which is called as the dry-bulb temperature. One mercury in glass thermometer whose sensing bulb is covered with a cotton or muslin wick made wet with pure water. This sensing bulb covered with the cotton wick moistened is made to contact the air and the temperature indicated by this thermometer is called as the wet bulb-thermometer. The instrument frame carrying the thermometer is covered by a glass casing. A swivel handle is attached to frame-glass casing – thermometer arrangement to ensure that the air at the wet bulb always in immediate contact with the wet wick. When a thermometer bulb is d...

 A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillator material and detecting the resultant light pulses. It consists of a scintillator that generates photons in response to incident radiation, a sensitive photomultiplier tube (PMT) which converts the light to an electrical signal and electronics to process this signal. Scintillation Counter Scintillation counters are widely used in radiation protection, an assay of radioactive materials and physics research because they can be made inexpensively yet with good quantum efficiency, and can measure both the intensity and the energy of incident radiation. Operation When an ionizing particle passes into the scintillator material, atoms are ionized along a track. For charged particles the track is the path of the particle itself. For gamma rays (uncharged), their energy is converted to an energetic electron via either the photoelectri...

 Falling Ball Viscometer uses the simple — but precise — Höppler principle to measure the viscosity of Newtonian liquids by measuring the time required for a ball to fall under gravity through a sample-filled tube. The principle of the viscometer is to determine the falling time of a ball of known diameter and density through a close to vertical glass tube of known diameter and length, filled with the fluid to be tested. The viscosity of the sample liquid is related to the time it takes for the ball to pass a distance between two specified lines on the cylindrical tube. Turning the measurement tube results in returning of the ball and it is possible to re-measure the time over the same distance. The result is dynamic viscosity with the standard dimension. Velocity of a ball which is falling through a liquid in a tube is dependent on the viscosity of the liquid. When the ball moves through the liquid, it is affected by the gravity, buoyancy and frictional forces: Gravity as downward...

 Variable area flow meters operate at a constant delta pressure (Δp) and the area changes with the flowrate. The area will increase as the flowrate through the meter increases to preserve a constant Delta Pressure (Δp). Variable Area Flow Meters The most common design of variable area meter is the cone-and-float type, which is also known as a rotameter. The basic design of a variable area meter is a tapered tube (usually glass) containing a self-centring float that is pushed up by the flow and pulled down by gravity. At higher flow rates the float rises to increase the area between the tube and the float and maintain a constant Δp. The flowrate is determined from how far the float has risen up the tube: there are graduations on the side of the tube.Variable area meters are widely used for metering gas but different types are available for a variety of different fluids. A buoyancy correction term is required for liquids and dense fluids. Variable area flowmeters are very simple yet ...

 Electromagnetic Flow Meters, simply known as mag flow meter is a volumetric flow meter which is ideally used for waste water applications and other applications that experience low pressure drop and with appropriate liquid conductivity required. The device doesn’t have any moving parts and cannot work with hydrocarbons and distilled water. Mag flow meters are also easy to maintain. Electromagnetic Flow Meters Principle of Magnetic Flow Meter Based on Faraday’s Law Magnetic flow meters works based on Faraday’s Law of Electromagnetic Induction. According to this principle, when a conductive medium passes through a magnetic field B, a voltage E is generated which is proportional to the velocity v of the medium, the density of the magnetic field and the length of the conductor. In a magnetic flow meter, a current is applied to wire coils mounted within or outside the meter body to generate a magnetic field. The liquid flowing through the pipe acts as the conductor and this induces a v...

 Mass flow meters are the types of flow meters which are mainly employed in mass-related processes such as chemical reactions, heat transfer, etc. In all these processes, accurate measurement of flow is the prerequisite. There are numerous types of mass flow meters available in the industry. However, the most widely used type is the Coriolis meter. Another type available is thermal type mass flow meters Coriolis Mass Flow Meter A Coriolis meter works on Coriolis Effect, hence it is named so. Coriolis meters are considered to be true mass meters since they tend to measure the mass rate of flow directly while other flow meter technologies measure volumetric flow. Since mass does not change, no adjustments are needed for varying fluid characteristics. Hence, a Coriolis meter operates in linear fashion. These types of meters exist in variety of designs. The most common type of unit includes 1.a U-shaped flow tube 2.a sensor assembly 3.an electronics unit In this meter unit, the liquid ...

 Two rotating impellers, designed with a figure eight cross section, rotate in opposite directions due to the forces exerted by the gas flow being measured. The shape of the impellers prevents contact while the gap between them remains constant. Lobed Impeller Flow Meters A gear drive external to the measuring chamber synchronizes the impellers. During each rotation four crescent shaped volumes are moved through the measuring chamber. The number of rotations is proportional to the flow. The rotation is coupled using an adjustable fine tooth gear train to the totalizer. An unmeasured flow, which is a function of the pressure drop, flows through the gaps. The negative error is compensated by an adjustment. The viscosity of flow increases at high pressures and reduces the losses in the gaps which compensates for the higher losses which would otherwise exist due to the higher pressure difference. The pulsations in the flow discharge can cause the pipe system connected to the meter to v...

 Swirl flow meters combine the advantages of turbine and vortex flow meter technologies. They have a high turndown ratio and high accuracy (turbine). And they are highly reliable, robust and maintenance free (vortex) Swirl Flow Meters Swirl Flow meters Principle A turbine-shaped inlet section forces the axial flow entering the flow meter into a rotational movement. A vortex core forms in the centre of the primary rotation. A secondary rotation forms in the vortex core producing thread-like spirals. The frequency of this secondary rotation is linearly proportional to the flow rate over a wide Reynolds Number range. Pressure variations resulting from the secondary rotation are detected by a piezo sensor and converted into electrical pulses. These pulses are processed in the DSP converter into scaled analog and digital signals which displays the measured flow value. Why Swirl Flow Meter is Advantage ? The swirl flow meter advances vortex flow technology by improving accuracy, simplify...

 Oscillating piston flow meters use a precision-machined chamber containing a cylindrical piston that oscillates as liquid flows. The piston’s central shaft is constrained to run in a circular groove in the chamber, resulting in an off-center rotating motion as the liquid sequentially enters and exits compartments machined into the underside of the piston. Since the volume of the compartments are known, the amount of liquid metered per revolution can be calculated accurately. Oscillating Piston Flow Meters Liquid enters a precision-machined chamber containing an oscillating (rotating) piston. The position of the piston divides the chamber into compartments containing an exact volume. Liquid pressure drives the piston to oscillate and rotate on its center hub. The movements of the hub are sensed through the flow meter wall by a follower magnet. Each revolution of the piston hub is equivalent to a fixed volume of fluid, which is indicated as flow by an indicator/totalizer. Close clea...

 Oval gear flow meters are a type of positive displacement meter. As liquid flows through the meter, a pair of oval shaped gears are forced to rotate by the flow of the liquid. These gears mesh together & force a finite amount of fluid through the meter. A sensor or mechanical drive detects the rotation of the gears to determine the displaced volume of liquid. The faster the flow rate, the faster the gears turn. Oval Gear Flow Meters Principles of Operation The oval gear flow meter comprises oval-shaped, geared rotors which rotate within a housing of specified geometry. Fluid differential pressure causes the inter-meshing gears to rotate, trapping a ‘pocket’ of fluid between the gear and the outer housing and subsequently emptying the fluid pocket into the downstream flow. Capillary action of the metered fluid forms a liquid seal. Each ‘pocket’ holds a precise and known volume of fluid so counting the pocket frequency gives a measurement of the volumetric flow rate. This is typ...

 When a venturi flow meter is placed in a pipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the venturi meter. This pressure drop is measured using a differential pressure sensor and when calibrated this pressure drop becomes a measure of flow rate. Venturi Flow Meter Construction of Venturi meter The following are the main parts and areas of venture meter: The entry of the venture is cylindrical in shape to match the size of the pipe through which fluid flows. This enables the venture to be fitted to the pipe. After the entry, there is a converging conical section with an included angle of 19’ to 23’. Following the converging section, there is a cylindrical section with minimum area called as the throat. After the throat, there is a diverging conical section with an included angle of 5’ to 15’. Openings are provided at the entry and throat (at sections 1 and 2 in the diagram) of the venture meter for attaching a di...

 The V-Cone flow meter like several other popular meters is a differential pressure (or “DP”) meter. These meters all work according to the same principle of DP flow devices. That is an obstruction in the pipe (i.e., a reduction in the cross sectional area available to the flow) causes an increase in flow velocity and a corresponding reduction in pressure. Hence be measuring the upstream pressure, the temperature and the difference in the static pressure between the upstream and the minimum cross sectional areas the flow rate can be determined as long as the fluid properties are known. The flow rate determination is done by applying the laws of conservation of mass and energy. However, there are important differences between the V-Cone meter design and other DP meter types. These differences give the V-Cone meter important performance advantages. These advantages include the ability of the V-Cone meter to operate with very short upstream and downstream straight pipe lengths, to cre...