(a) Temperature Measurement and Remote Indication (Sketch):
Imagine a probe inserted into the object or environment you want to monitor. Let’s call it a thermocouple, made of two dissimilar metals joined at the tip. Here’s how it works:
Sketch:
- Hot Junction: The tip of the thermocouple experiences the temperature you want to measure.
- Dissimilar Metals: Each metal in the thermocouple has a unique relationship between temperature and voltage.
- Voltage Difference: When the hot junction experiences a temperature change, the voltage difference between the two metals at the junction also changes.
- Connecting Wires: Two or four wires connect the thermocouple to a measuring device.
- Measuring Device: This device detects the voltage change and converts it into a temperature reading based on pre-programmed equations specific to the chosen metal pair.
- Remote Indicator: The temperature reading is then displayed on a remote panel or transmitted wirelessly for monitoring.
Key Points:
- Thermocouples are simple, robust, and widely used for temperature measurement.
- The choice of metal pair influences the temperature range and sensitivity of the thermocouple.
(b) Flow Rate Measurement and Remote Indication (Sketch):
Now, imagine a device installed in a pipe carrying the fluid you want to measure. Let’s call it a magnetic flow meter. Here’s how it works:
Sketch:
- Magnetic Field: The meter generates a magnetic field across the flowing liquid within the pipe.
- Moving Conductors: The moving fluid particles act as conductors within the magnetic field.
- Induced Voltage: The interaction between the moving conductors and the magnetic field induces a voltage proportional to the flow velocity.
- Electrodes: Sensors within the meter pick up this induced voltage.
- Flow Calculation: The electronic unit within the meter converts the voltage to a flow rate value based on the pipe cross-section and calibration factors.
- Remote Indicator: The flow rate reading is then displayed on a remote panel or transmitted wirelessly for monitoring.
Key Points:
- Magnetic flow meters are non-invasive and accurate for measuring flow rates.
- They work with various conductive fluids and are not affected by pressure or temperature changes.
Remember, these are just two examples, and various other technologies can be used for temperature and flow rate measurement and remote indication. Choosing the right method depends on factors like accuracy requirements, fluid properties, budget, and environmental conditions.