State a type of transducer or measuring device suitable for measuring EACH of the following parameters:
(a) accurate remote reading of a diesel engine exhaust temperature;(1)
(b) accurate remote reading of the twist of a propeller shaft;(1)
(c) accurate and remote position of a diesel engine governor or fuel rack;(1)
(d) the speed of a ship’s main propeller shaft in RPM;(1)
(e) remote reading of a ship’s intermediate shaft bearing temperature;(1)
(f) remote reading of lubricating oil pressure in a diesel engine;(1)
(g) flow rate of a water maker;(1)
(h) simple local pressure reading of ships fire-main;(1)
(i) the position of the steering gear or rudder;(1)
(j) local reading of jacket cooling water temperature.(1)
Transducer for Remote Diesel Engine Exhaust Temperature
A thermocouple is the most commonly used transducer for measuring and remotely monitoring diesel engine exhaust temperature.
Why a Thermocouple?
- Wide temperature range: Thermocouples can accurately measure temperatures from extremely low to extremely high values, making them suitable for the harsh environment of an engine exhaust. 1. Modern Thermocouples and a High-Resolution Delta-Sigma ADC Enable High-Precision Temperature Measurement | Analog Devices www.analog.com
- Robustness: They are durable and can withstand the vibrations and harsh conditions typically found in engine compartments. 1. How accurate are thermocouples? Learn More | Pyrosales www.pyrosales.com.au
- Fast response time: Thermocouples provide quick and accurate temperature readings, essential for real-time monitoring. 1. How Do Thermocouples Work? A Quick Tutorial – WIKA blog blog.wika.us
- Simple installation: They can be easily installed in various locations within the exhaust system.
Additional Considerations:
- Thermocouple type: The choice of thermocouple type depends on the expected temperature range. Common types for high-temperature applications include Type K (Nickel-Chromium/Nickel-Aluminum) and Type J (Iron/Constantan). 1. Thermocouples: Function, Types, Selection and Application – enDAQ Blog blog.endaq.com
- Signal conditioning: The thermocouple output is a millivolt signal, which often requires amplification and conditioning before it can be transmitted and displayed. 1. Two Ways to Measure Temperature Using Thermocouples Feature Simplicity, Accuracy, and Flexibility | Analog Devices www.analog.com
- Data acquisition system: A data acquisition system (DAS) is necessary to collect the thermocouple signal, convert it to a digital format, and transmit it to a remote display or control system.
By combining a thermocouple with appropriate signal conditioning and data acquisition equipment, you can effectively monitor diesel engine exhaust temperature remotely.
Measuring Propeller Shaft Twist
Strain gauges are the most suitable transducers for measuring the twist of a propeller shaft.
How it works:
- Strain gauges are bonded: Directly onto the propeller shaft at specific locations.
- Twist deformation: As the shaft twists under load, the strain gauges experience a change in resistance.
- Signal conditioning: This change in resistance is converted into an electrical signal through a Wheatstone bridge circuit.
- Data acquisition: The signal is amplified, conditioned, and digitized for remote transmission.
Additional considerations:
Data transmission: A reliable wireless or wired communication system is necessary for remote monitoring.
Gauge placement: The strain gauges should be positioned to accurately capture the shaft’s torsional deformation.
Calibration: The system requires careful calibration to correlate the strain gauge output with the actual shaft twist angle.
Environmental protection: Strain gauges must be adequately protected from the harsh marine environment (corrosion, vibration, etc.).
By using strain gauges and appropriate signal conditioning, it’s possible to accurately measure and monitor propeller shaft twist for various applications, such as performance analysis, condition monitoring, and fault detection.
Transducer for Remote Reading of Diesel Engine Governor or Fuel Rack Position
Potentiometer
A potentiometer is a suitable transducer for measuring the position of a diesel engine governor or fuel rack.
How it works:
- A potentiometer is a variable resistor with a sliding contact.
- As the governor or fuel rack moves, the sliding contact changes its position on the resistive element.
- This change in position results in a corresponding change in electrical resistance.
- The resistance change can be converted into a voltage signal, which is proportional to the position.
Advantages of potentiometers:
- Simple and relatively inexpensive.
- Provide a continuous output signal.
- Suitable for linear or rotational movement.
Other options:
- Linear Variable Differential Transformer (LVDT): Offers higher accuracy and durability compared to potentiometers, but is more complex and expensive.
- Rotary Variable Differential Transformer (RVDT): Similar to LVDT but designed for rotational movement.
- Hall Effect sensor: Can be used for non-contact position measurement, but might require additional components for linear or rotational measurement.
Important considerations:
- Environmental conditions: The chosen transducer must be suitable for the harsh environment of an engine compartment.
- Accuracy requirements: The required precision of the measurement will determine the choice of transducer.
- Signal conditioning: The output signal from the transducer often requires amplification and conditioning before it can be used for remote monitoring.
By carefully selecting the appropriate transducer and implementing proper signal conditioning, you can effectively monitor the position of a diesel engine governor or fuel rack for remote control and diagnostics.
Measuring Propeller Shaft RPM
Tachometer
A tachometer is the most common and straightforward device for measuring propeller shaft RPM.
Types of Tachometers for this Application:
- Magnetic Pickup Tachometer: This type uses a sensor to detect the passage of a metal target attached to the rotating shaft. It’s robust and reliable for harsh environments.
- Eddy Current Tachometer: This type uses electromagnetic induction to measure shaft speed. It’s non-contact and offers high accuracy. 1. Eddy-current tachometer | instrument – Britannica www.britannica.com2. Eddy current probe T serie high accuracy – Sensel Measurement sensel-measurement.fr
- Laser Tachometer: This type uses a laser beam to measure the surface speed of the shaft. It’s non-contact and can measure from a distance. 1. A Complete Guide to Tachometers – RS Components uk.rs-online.com2. Digital Laser Tachometer with data logging and non-contact measurement – Diesella www.diesella.com
Additional Considerations:
- Signal Conditioning: The tachometer’s output signal may require amplification or conditioning before it can be transmitted.
- Data Transmission: The signal can be transmitted wirelessly or through wired connections to a remote display or control system.
By carefully selecting the appropriate tachometer type and considering the environmental conditions, you can accurately measure and monitor propeller shaft RPM for various applications, such as engine performance monitoring, fuel efficiency optimization, and alarm systems.
Transducer for Intermediate Shaft Bearing Temperature
Thermocouples are the most suitable transducers for measuring the temperature of a ship’s intermediate shaft bearing.
Why Thermocouples?
- Wide Temperature Range: Thermocouples can accurately measure a broad range of temperatures, making them suitable for the high temperatures experienced in bearing applications.
- Robustness: They are durable and can withstand the harsh marine environment and vibration.
- Fast Response Time: Thermocouples provide quick and accurate temperature readings, essential for monitoring bearing health.
- Relatively Inexpensive: Compared to other options, thermocouples are cost-effective.
Additional Considerations:
- Thermocouple Type: The specific type of thermocouple (e.g., Type K, J, or T) should be chosen based on the expected temperature range.
- Installation: The thermocouple should be securely attached to the bearing housing or a nearby point that accurately reflects the bearing temperature.
- Signal Conditioning: The thermocouple output is a millivolt signal, which usually requires amplification and conditioning before transmission.
- Data Acquisition System: A data acquisition system (DAS) is necessary to collect the thermocouple signal, convert it to a digital format, and transmit it to a remote display or control system.
By combining a suitable thermocouple with appropriate signal conditioning and data acquisition equipment, you can effectively monitor the temperature of the intermediate shaft bearing for early detection of overheating and potential bearing failures.
Transducer for Remote Reading of Lubricating Oil Pressure
A pressure transducer is the ideal device for remotely measuring lubricating oil pressure in a diesel engine.
How it works:
- The pressure transducer converts the oil pressure into an electrical signal. 1. Defining a Pressure Transducer | Blue Ribbon Corp blueribboncorp.com
- This signal can be processed and transmitted to a remote display or control system. 1. How Does A Pressure Transducers Work? – Omega Engineering www.omega.com
Types of Pressure Transducers:
- Strain Gauge Pressure Transducer: This type utilizes strain gauges to measure the pressure-induced deformation of a diaphragm. 1. Piezoresistive Pressure Sensors | The Design Engineer’s Guide | Avnet Abacus my.avnet.com
- Piezoresistive Pressure Transducer: Similar to strain gauge type but uses a semiconductor material for better sensitivity.
- Piezoelectric Pressure Transducer: Generates an electrical charge proportional to the applied pressure. 1. Piezoelectric Pressure Sensors | The Design Engineer’s Guide | Avnet Abacus my.avnet.com
Considerations:
- Pressure Range: The transducer should be selected based on the expected oil pressure range.
- Accuracy: The required precision of the measurement will determine the transducer’s specifications.
- Environmental Conditions: The transducer must be compatible with the engine’s environment (temperature, vibration, etc.).
- Signal Conditioning: The transducer’s output signal may require amplification and conditioning before transmission.
- Data Transmission: The signal can be transmitted wirelessly or through wired connections to a remote display or control system.
By carefully selecting a pressure transducer and considering the specific requirements of the application, you can accurately monitor lubricating oil pressure for early detection of potential problems and optimize engine performance.
Measuring Water Flow Rate in a Water Maker
Turbine Flow Meter
A turbine flow meter is an excellent choice for measuring the flow rate of a water maker.
1. A Guide to Turbine Flow Meters – KOBOLD USA
How it works:
- The flowing water rotates a turbine within the meter.
- The rotation speed of the turbine is proportional to the flow rate.
- A sensor measures the turbine’s rotation speed, which is converted into a flow rate reading.
Advantages:
- High accuracy and repeatability. 1. High Accuracy Flow Meters – Turbines, Inc. www.turbinesincorporated.com
- Wide flow rate range. 1. Turbine Flow Meters | Turbine Flowmeters from Metri Measurement metrimeasurements.co.uk
- Relatively low cost.
- Suitable for both clean and slightly dirty water.
Other Options:
- Electromagnetic Flow Meter: This type is suitable for conductive fluids and offers high accuracy, but it’s generally more expensive.
- Ultrasonic Flow Meter: Uses sound waves to measure flow velocity, but it can be affected by fluid properties and requires careful installation. 1. How Do Ultrasonic Flow Meters Work? – Coltraco coltraco.com
- Positive Displacement Flow Meter: Offers high accuracy but is more complex and expensive, and typically suitable for lower flow rates.
Considerations:
- Flow Rate Range: Choose a meter with a flow rate range that matches the water maker’s output.
- Accuracy Requirements: Determine the required accuracy for your application.
- Installation: Consider the installation requirements and the meter’s compatibility with the water maker’s piping system.
- Signal Conditioning: The meter’s output may require amplification or conditioning before it can be used for remote monitoring.
By carefully selecting a turbine flow meter and considering the specific requirements of the water maker, you can accurately measure and monitor the water production rate.
Transducer for Measuring Fire Main Pressure
A pressure gauge is the most suitable device for measuring simple local pressure readings in a ship’s fire main.
Pressure Gauges
- Analog Dial Gauge: This is the most common type, providing a direct visual indication of the pressure. It’s simple, reliable, and relatively inexpensive.
- Digital Pressure Gauge: Offers more precise readings and can be easily interfaced with other systems for data logging or alarms.
Considerations:
- Pressure Range: The gauge should be selected based on the expected pressure range in the fire main.
- Accuracy: The required precision of the measurement will determine the gauge’s specifications.
- Installation: The gauge should be installed in a location where it is easily visible and accessible for monitoring.
- Material Compatibility: Ensure the gauge’s materials are compatible with the fire main fluid (typically seawater).
By selecting an appropriate pressure gauge and considering the specific requirements of the fire main system, you can effectively monitor the pressure for troubleshooting and safety purposes.
Measuring Steering Gear or Rudder Position
Rotary Potentiometer is a suitable transducer for measuring the position of a steering gear or rudder.
How it works:
- A potentiometer is a variable resistor with a sliding contact. 1. A Complete Guide to Potentiometers – RS Components uk.rs-online.com
- As the steering gear or rudder moves, the sliding contact rotates along the resistive element.
- This change in position results in a corresponding change in electrical resistance.
- The resistance change can be converted into a voltage signal, which is proportional to the position. 1. 4.5 Resistance to Voltage – Princeton Sound Lab soundlab.cs.princeton.edu
Advantages of Potentiometers:
- Simple and relatively inexpensive. 1. All You Need to Know About Potentiometers – CUI Devices www.cuidevices.com
- Provide a continuous output signal. 1. The Complete Guide to Potentiometers – DigiKey www.digikey.com
- Suitable for rotational movement. 1. Rotary Potentiometers: Precision Control for Electronic Applications – ETI Systems etisystems.com
Other options:
- Rotary Variable Differential Transformer (RVDT): Offers higher accuracy and durability compared to potentiometers, but is more complex and expensive.
- Absolute Encoder: Provides a digital output representing the angular position, offering high accuracy and resolution.
Considerations:
- Environmental conditions: The chosen transducer must be suitable for the harsh marine environment (water, salt, vibration).
- Accuracy requirements: The required precision of the measurement will determine the choice of transducer.
- Signal conditioning: The output signal from the transducer often requires amplification and conditioning before it can be used for remote monitoring.
By carefully selecting the appropriate transducer and implementing proper signal conditioning, you can effectively monitor the position of a steering gear or rudder for various applications, such as autopilot, steering alarms, and data logging.
Transducer for Jacket Cooling Water Temperature
A thermocouple is the most suitable transducer for measuring jacket cooling water temperature.
Why a Thermocouple?
- Wide temperature range: Thermocouples can accurately measure a broad range of temperatures, making them suitable for engine cooling applications.
- Robustness: They are durable and can withstand the harsh environment of an engine compartment.
- Fast response time: Thermocouples provide quick and accurate temperature readings, essential for monitoring engine health.
- Relatively inexpensive: Compared to other options, thermocouples are cost-effective.
Additional Considerations:
- Thermocouple Type: The specific type of thermocouple (e.g., Type K, J, or T) should be chosen based on the expected temperature range.
- Installation: The thermocouple should be installed in a location that accurately reflects the jacket cooling water temperature.
- Signal Conditioning: The thermocouple output is a millivolt signal, which usually requires amplification and conditioning before display.
By combining a suitable thermocouple with appropriate signal conditioning, you can effectively monitor jacket cooling water temperature for early detection of overheating and potential engine problems.