Que2.17. How ultrasonic inflow detector work?
Answer 1. Ultrasonic inflow detectors use sound swells to determine the haste of a fluid flowing in a pipe. 2. At no inflow conditions, the frequentness of an ultrasonic surge transmitted into a pipe and its reflections from the fluid are the same. 3. Under flowing conditions, the frequence of the reflected surge is different due to the Doppler Effect. 4. When the fluid moves briskly, the frequence shift increases linearly. The transmitter processes signals from the transmitted surge and its reflections to determine the inflow rate. 2.17.1. Detectors Water inflow 5. Conveyance time ultrasonic inflow detectors shoot and admit ultrasonic swells between transducers in both the upstream and downstream directions in the pipe. 6. At no inflow conditions, it takes the same time to travel upstream and downstream between the transducers. 7. Under flowing conditions, the upstream surge will travel slower and take further time than the( briskly) downstream surge. 8. When the fluid moves briskly, the difference between the upstream and downstream times increases. 9. The transmitter processes upstream and downstream times to determine the inflow rate.
Que2.18. What are the advantages, disadvantages and operations of ultrasonic inflow detectors?
Answer
Advantages 1. It doesn’t block the path of liquid inflow.
2. The affair of this cadence is different for viscosity, density and temperature of the liquid.
3. The inflow of liquid is bidirectional.
4. The dynamic response of this cadence is good.
5. The affair of this cadence is in analog form.
6. Versatility is good.
7. There’s no contact to liquid.
8. There’s no leakage threat.
9. There are no moving corridor, pressure loss.
10. High delicacy.
Disadvantages
1. It’s precious as compared with other mechanical inflow measures.
2. Design of this cadence is complex.
3. audile corridor of this cadence are precious.
4. These measures are complicated as compared with other measures.
5. It can not measure cement or concrete pipes bonethey rusted.
6. It does n’t work once the pipe contains holes or bubbles in it.
Applications
1. These measures are used in wastewater and dirty liquid operations.
2. These measures are used wherever chemical comity, lower conservation, and low- pressure drop are needed.
3. These measures are used to measure the haste of a liquid through ultrasound to dissect volume inflow.
4. These measures measure the difference between the conveyance time of ultrasonic beats which transmits with the direction of liquid inflow.
5. This is one kind of device for volumetric inflow dimension for liquids as well as feasts.
Que2.19. bandy the working of ray( or optic) inflow detector.
Answer 1. Ray( or optic) inflow detector work on the principle of optics i.e., they measure the inflow rate using light.
2. generally, they employ a set- up conforming of a ray ray and photodetectors.
3. Then, the patches of the gas flowing through the pipe scatter the ray ray to produce beats which are picked- up by the receiver as shown in 2.19.1.
4. also, the time between these signals is determined as one would know the distance by which the print- sensors would be separated, which in turn leads to the dimension of the speed of gas.
5. As these measures measure the factual speed of the patches constituting the feasts, they remain innocent by the thermal conditions and the variations in gas inflow.
6. Hence, they’re able of furnishing largely accurate inflow data indeed when the terrain is most unfavourable.
Que2.20. How ultrasonic position detectors work?
Answer 1. Ultrasonic position detectors work by the “ time of flight ” principle using the speed of sound.
2. The detector emits a high- frequence palpitation, generally in the 20 kHz to kHz range, and also listens for the echo. Ultrasonic/ position detectors measure distance by using ultrasonic swells.
3. The detector head emits an ultrasonic surge and receives the surge reflected back from the target.
4. Ultrasonic/ position detectors measure the distance to the target by measuring the time between the emigration and event.
5. principally, the transmitter divides the time between the palpitation and its echo by two, and that’s the distance to the face of the material.
6. The transmitter is designed to hear to the loftiest breadth return palpitation( the echo) and mask out all the other ultrasonic signals in the vessel.
7. The distance can be calculated with the following formula, . The value is multiplied by1/2 because T is the time for go- and- return distance.
Que2.21. What are the advantages and disadvantages of ultrasonic position detectors?
Answer Advantages 1. Non-contact with product.
2. Suitable for wide range of liquids and bulk products like maquillages and grains.
3. Reliable performance in delicate service.
4. No moving corridor.
5. dimension without physical contact.
6. delicacy of0.25 with temperature compensation and tone- estimation.
Disadvantages
1. Not suitable for advanced pressures or in a vacuum.
2. The temperature is limited to 170 °C.
Que2.22. bandy the working principle of capacitive position detectors.
Answer Working principle 1. The principle of capacitive position dimension is grounded on change of capacitance.
2. An insulated electrode acts as one plate of capacitor and the tank wall or reference electrode in anon-metallic vessel) acts as the other plate. The capacitance depends on the fluid position.
3. An empty tank has a lower capacitance while a filled tank has a advanced capacitance.
4. A simple capacitor consists of two electrode plate separated by a small consistence of an insulator similar as solid, liquid, gas, or vacuum. This insulator is also called as dielectric.
5. Value of C depends on dielectric used, area of the plate and also distance between the plates. A = Effective area of the operators d = Distance between the operators.
6. This change in capacitance can be measured using AC Bridge.
Measurement
1. dimension is made by applying a Radio frequence( RF) signal between the conductive inquiry and the vessel wall.
2. The RF signal results in a veritably low current inflow through the dielectric process material in the tank from the inquiry to the vessel wall.
3. When the position in the tank drops, the dielectric constant drops causing a drop in the capacitance reading and a nanosecond drop in current inflow.
4. This change is detected by the position switch’s internal circuitry and restated into a change in the relay state of the position switch in case of point position discovery.
5. In the case of nonstop position sensors, the affair isn’t a relay state, but a gauged analog signal.
Que2.23. Give the advantages, disadvantages and operations of capacitive position detectors.
Answer :
Advantages
1. fairly affordable
2. protean
3. Bear minimum conservation
4. Reliable
5. Contains no moving corridor
6. Easy to clean
7. Rugged
8. Simple to use.
Disadvantages
1. This system can not work with accoutrements having varying dielectric accoutrements .
2. Indeed acids and caustics that do n’t appear to cover the seeing element are so conductive that the thin film they leave can beget serious crimes in dimension.
Applications
1. To measures situations of Liquids ii. Powered and grainy solids iii. Liquid essence at veritably high temperature iv. thawed feasts at veritably low temperature sharp accoutrements like hydrofluoric acid
2. veritably high pressure artificial processes.