In: Electrical Engineering
Hello , I want you to give me an exercise with the solution and the equations for every principle mention below , thank you !
- Proximity sensors.
- Optical flowmeter.
- Turbine flowmeter.
- Ultrasonic flowmeter.
- Ultrasonic level gauge.
Optical flow meter.
Principal: the optical flow meter uses light reflection to measure the velocity of flow stream and optical flow meter measures the time of flight of light to measure the flow of stream.
Construction and working:
A dual beam laser used as source to optical flow meter and opposite sides of the pipe line is attached to the optical window to let the light into the pipe line. The light detection sensors are placed at an inclination to the straight line path of the light then the detection of light is converted into an electrical signal and also signal is processed.
The light is pass through the optical window and the light propagated through the fluid then comes out through the optical window at another end. If there is no fluid flow in the pipe line , light goes through the straight and it can not be detected by sensors. If the fluid flow through the pipe line, the incident of light hits the particles in the fluids then the light gets scattered and deviates from main path. The deviation of light is detected by detectors. Let this happen at the first sensor the particles moves to the second beam of light.
The same happen to the second beam and the light deviated, gets detected at the second sensor. The delay of time between two successive pulses is measured. The time delay is proportional to the flow rate of stream.therefore
V= d/t
V= velocity of particle
d = distance of separating two laser beams
t = time difference between sensor pulses
Proximity sensor.
A proximity sensor is non contact sensor .it detects the presence of an object when the target enters the sensor field and depending on type of proximity sensor, sound light infrared radiation or electromagnetic fields utilized by the sensors to detect a targets.
Proximity sensors are used in phones , recycling plants ,self drive cars ,anti air crafted systems and assembly lines. There are many types of proximity sensors and each sense targets in distinct way . Mostly used proximity sensors are inductive proximity sensor and capacitive proximity sensor
An inductive proximity sensor is only detect metal targets beacause of sensor utilize elctromagelectr field. When metal target enters into the electromagnetic field, then the induction characteristics of metal change the fields properties hence alert the proximity sensor of presence of metalic target, depending on inductive metal is ,the target can be detected at either greater distance or shorter distance.Turbine flow meter.
Turbine flow meter is volumetric measuring turbine type, the flowing fluid engage the rotor causing it to rotate at angular velocity proportional to the fluid flow rate. The angular velocity of the rotor gets in the generation of electrical signal and the summation of pulsing electrical signal is relates directly to the total flow. The frequency of signal is directly related to the flow rate. The vaned rotor is only moving part of the flow meter.
Flow meter consists of flow tube with end connections and magnetic multi bladed free spinning rotor mounted inside the flow meterand this rotor supported by shaft that rest on internally mounted supports. These supporters are also act as flow straightners stabelise the flow and reduce the negative effects of turbulence.the supporters also Insert the unique open bearings allowing to the lubricante brushes prolong the life span of flow meter and supporters are fastened by locking rings at each end.
The rotor sits on shaft in turn is suspended in the flow by two supporters. As flows force is applied on rotor wings the angle and shape of wings transform the horizontal force into perpendicular force then rotation takes place hence the rotarrot of rotor is directly proportional to applied force of flow.a pick up sensor mounted on rotor when the magnetic blades pass through the sensor a signal is generated for each blade. It provides a pulsed signal proportional to the speed of rotor and indicates pulses per volumetric unit .