Ship Machinery Alarms and Protection Devices

Summary

The video script highlights the critical role of alarm and protection systems in preventing machinery breakdowns on ships. It emphasizes the importance of proper operation, maintenance, and testing of these systems to ensure reliability and safety. The script provides insights into the hierarchy of alarm priorities, from top-priority systems like main propulsion engines and steering to less critical ones like cargo pumps. It also stresses the necessity for engineers to understand and respond effectively to alarms, underscoring the significance of good engineering practice in averting disasters.

Takeaways

• 🔍 **Importance of Alarm Systems**: The script emphasizes the crucial role of alarm systems and protection devices in preventing machinery breakdowns and disasters on ships.
• 🛠️ **Maintenance and Operation**: It highlights that many breakdowns occur due to inadequate maintenance, incorrect operation, or deliberate disconnection of alarm systems.
• 🚫 **Consequences of Neglect**: The script warns that neglecting alarm systems can lead to serious incidents, including injuries, major breakdowns, and operational disruptions.
• 🔑 **Attention to Detail**: It stresses the importance of duty engineers paying close attention to detail to avoid unforeseen incidents and maintain the reliability of ship systems.
• 🛑 **Protection Circuits**: The text explains that protection circuits not only provide warnings but also initiate shutdown procedures to prevent damage to critical machinery.
• 📊 **Prioritization of Alarms**: It discusses the prioritization of alarm systems based on their importance to the ship's operation, with some being top priority and others less critical.
• 🔬 **Testing and Calibration**: The script insists on the necessity of regular testing and calibration of sensors and alarm systems to ensure their accurate function.
• 📝 **Documentation**: It mentions the importance of recording test results and maintaining documentation for future reference and quality control.
• 👨‍🔧 **Engineer's Responsibility**: The text underscores the duty engineer's responsibility to understand the alarm and protection systems, including their relative importance and the necessary actions upon activation.
• 🚫 **Avoidance of Premature Reset**: The script advises against pressing the reset on alarms without understanding and addressing the cause, to prevent recurring issues.
• 🛡️ **Confidence in Systems**: Lastly, it concludes with the need for engineers to have confidence in the alarm system and protection devices for timely warning and remedial action.

Q & A

What are the common causes of machinery breakdowns mentioned in the script?

The script mentions that a large number of machinery breakdowns occur due to mistakes in operation or maintenance of the alarm systems and protection devices, including being deliberately disconnected, clogged up with paint, or neglected and forgotten.

What is the consequence of ignoring alarm systems and protection devices on a ship?

Ignoring alarm systems and protection devices can lead to serious breakdowns, potential injuries to people, major machine damage, and disruptions to the commercial operation of the vessel, resulting in extra workload for the ship's personnel.

How does a typical alarm circuit function in the context of the script?

A typical alarm circuit has a censoring device such as a level sensor, thermocouple, or pressure sensor connected to display devices. When certain values are reached, a switch is activated, sending an electrical or pressure signal to the ship's alarm panels, causing an audio-visual warning that remains until acknowledged and the issue is resolved.

What is the purpose of a protection circuit in addition to a warning circuit?

A protection circuit, in addition to providing a warning, initiates a shutdown procedure of the affected machines by activating one or more switches or valves, causing the machine to halt in a controlled manner to prevent damage.

Why is it important for engineers to understand the alarm and protection systems on a ship?

It is important for engineers to understand these systems to ensure they can respond appropriately to alarms, know the relative importance of each system to the ship's operation, and maintain the reliability of the ship's systems by preventing potential hazards.

What are some examples of top-priority alarm and protection circuits on a ship?

Top-priority alarm and protection circuits include those that protect the main propulsion engine, steering system, power generation plant, and steam boilers, as any breakdown in these systems can be catastrophic.

How do level indicators function as part of the alarm system?

Level indicators monitor liquid levels in tanks and are activated by the liquid itself. When the level rises or sinks below set safety levels, a sensor sends a signal to warning devices, usually with an indicator.

What is a flame out alarm system and why is it important?

A flame out alarm system uses optical sensors, known as flame eyes, to continuously monitor the presence of flame in a boiler. It provides an instant warning if the flame goes out, which is critical because a sudden loss of flame can lead to undesirable and dangerous consequences.

How should engineers test sensors to ensure the reliability of the alarm system?

Engineers should test sensors regularly according to the ship's maintenance or test schedules. They must use calibrated test instruments and record the details of the test for future reference. The testing should cover both minimum and maximum limits of the sensor's operation.

What steps should be taken when an alarm is activated on a ship?

When an alarm is activated, the duty engineer must identify the significance of the alarm, determine the system's importance, take measures to eliminate the cause of the alarm, and execute countermeasures in the correct order. They should never reset an alarm without understanding and addressing the cause.

Why is it essential for engineers to have confidence in the alarm system and protection devices?

Confidence in the alarm system and protection devices is essential because it ensures that engineers will be given timely warnings of any changing conditions that may lead to a breakdown, allowing them to take remedial action and maintain good engineering practice.

Outlines

00:00

🚨 Importance of Alarm Systems and Maintenance

This paragraph discusses the critical role of alarm systems and proper maintenance in preventing machinery breakdowns. It highlights how negligence in checking and maintaining these systems can lead to serious incidents, including major equipment damage and operational disruptions. The text emphasizes the need for engineers to pay meticulous attention to the alarm and protection systems to ensure the reliability and safety of the ship's operations.

05:02

🔍 Understanding Alarm and Protection Circuits

The second paragraph delves into the specifics of alarm and protection circuits, explaining how they function using sensors and switches to monitor machinery conditions. It outlines the importance of recognizing priority levels of different systems on a ship, such as main propulsion engines and power generation plants, which are considered top priority due to their critical role in ship operations. The paragraph also introduces the concept of warning-only alarms that do not initiate shutdowns but alert to potential hazards.

10:06

🛠️ Testing and Calibration of Sensor Systems

This paragraph focuses on the necessity of regular testing and calibration of sensors to ensure the reliability of alarm and protection systems. It details the process of testing temperature and pressure sensors, emphasizing the importance of using calibrated instruments and recording test results for future reference. The text stresses the need for engineers to understand the critical nature of these systems and to follow proper maintenance schedules to prevent malfunctions.

15:08

⚠️ Alarm System Best Practices and Engineer's Role

The final paragraph concludes with best practices for alarm system management and the crucial role of engineers in maintaining these systems. It advises on the importance of understanding the significance of different alarms, following maintenance schedules, and ensuring all sensors and display systems are fully operational. The paragraph also discusses the correct procedures for responding to alarms, including investigating the cause before resetting and never restarting equipment without addressing the underlying issue.

Keywords

💡Machinery Breakdowns

Machinery breakdowns refer to the failure of mechanical equipment to function properly. In the context of the video, these breakdowns are often attributed to human error in operation or maintenance. The script emphasizes that such incidents can be avoided with proper attention to detail, illustrating the theme of the importance of maintenance and operational procedures in preventing costly and dangerous equipment failures.

💡Alarm Systems

Alarm systems are critical components in machinery that alert operators to potential issues before they escalate into larger problems. The video script discusses how failures in alarm systems can lead to machinery breakdowns, as they are designed to monitor and signal when machinery is operating outside of safe parameters. The importance of maintaining these systems is highlighted, as a neglected alarm system can result in undetected issues and subsequent disasters.

💡Protection Devices

Protection devices are mechanisms that automatically shut down or adjust machinery in response to certain conditions to prevent damage. The script mentions that these devices, when connected to alarm systems, can prevent machinery from operating in a dangerous state. The video underscores the necessity of these devices for the safe operation of machinery, especially when they are not functioning correctly, which can lead to serious consequences.

💡Operational Procedures

Operational procedures are the set of instructions or protocols that guide the use and maintenance of machinery. The video script suggests that incorrect operational procedures can lead to machinery breakdowns and emphasizes the need for proper training and adherence to these procedures to ensure safety and efficiency.

💡Maintenance Regime

A maintenance regime refers to the routine checks and services performed on machinery to ensure it remains in good working order. The script warns against the development of a less than meticulous maintenance regime, which can lead to machinery failures. It is a key concept in the video, illustrating the necessity of regular and thorough maintenance to prevent breakdowns.

💡Blackout

A blackout, as mentioned in the script, is a complete loss of electrical power. The video uses the term to describe a scenario where machinery failure leads to a total shutdown of systems. It serves as an example of the cascading effects of neglecting alarm and protection systems, highlighting the urgency of addressing the root cause of an alarm before it leads to a complete system failure.

💡Consequential Breakdowns

Consequential breakdowns are secondary failures that occur as a result of an initial malfunction. The script discusses how an unscheduled event, such as a blackout, can cause these additional breakdowns. This concept is integral to the video's message, demonstrating how a single point of failure can impact multiple systems and exacerbate the overall problem.

💡Censoring Device

A censoring device, as described in the script, is a sensor that detects changes in conditions such as level, temperature, or pressure. These devices are crucial for triggering alarm systems when certain thresholds are reached. The video explains that these devices, when connected to display devices, are the first line of defense in alerting operators to potential issues.

💡Audio-Visual Warning Devices

Audio-visual warning devices are mechanisms that provide both audible and visual alerts to indicate an alarm condition. The script explains that these devices are activated by censoring devices and remain active until the duty engineer acknowledges the alarm and addresses the issue. They are essential for capturing the attention of operators and ensuring a timely response to potential hazards.

💡Shutdown Procedure

A shutdown procedure is the process by which machinery is safely and systematically brought to a stop. The script mentions that activation of a limit switch in a protection circuit initiates this procedure. It is a critical aspect of the video's theme, illustrating how protection devices work in conjunction with alarm systems to prevent further damage in the event of a malfunction.

💡Calibration

Calibration is the process of adjusting a measuring instrument to ensure its accuracy. The script stresses the importance of using calibrated instruments when testing sensors to ensure their reliability. It is a key concept in the video, as it relates to the accuracy and trustworthiness of the alarm and protection systems on board a ship.

💡Test Pump and Gauge

A test pump and gauge are tools used to simulate pressure conditions for testing pressure sensors. The script describes their use in testing lube oil inlet pressure sensors, emphasizing the importance of regular testing to ensure the functionality of alarm and protection systems. This tool is highlighted in the video as part of the maintenance process to guarantee the reliability of the machinery's monitoring systems.

Highlights

A large number of machinery breakdowns occur due to mistakes in operation or maintenance of alarm systems and protection devices.

Engines, generators, boilers, and compressors can be fatally damaged if alarm systems and protection devices are prevented from working.

Attention to detail by duty engineers can avoid unforeseen incidents and major machine breakdowns.

Neglecting alarm systems and protection devices can lead to unscheduled events and consequential breakdowns.

Engineers on board must ensure alarm systems work properly at all times for reliable ship operation.

A typical alarm circuit has a censoring device connected to display devices that trigger an alarm when certain values are reached.

Protection circuits initiate a shutdown procedure of affected machines when limit switches are activated.

Alarm and protection systems are crucial for monitoring and protecting vital ship components like main propulsion engines and steering systems.

Understanding the relative importance of different alarm and protection circuits is essential for engineers.

Boiler water level alarms are critical for ensuring safe operation and preventing dangerous situations.

Flame out alarm systems with optical sensors provide instant warning in case of sudden flame loss in boilers.

Main propulsion engine alarm and protection devices use temperature and pressure sensors for monitoring operational conditions.

Regular testing of sensors in accordance with maintenance schedules ensures accurate function of alarm and protection systems.

Only calibrated test instruments should be used for testing sensors to maintain system reliability.

Engineers must know the alarm and protection systems thoroughly, including their importance to the ship's proper function.

When an alarm activates, the duty engineer must be able to answer critical questions about the alarm and take appropriate measures.

Never press the reset on an alarm without noting the cause to prevent recurrence of the issue.

Adjustments to temperature or pressure switches should be made using calibrated instruments and considering the direction of change.

Engineers must have confidence in the alarm system and protection devices for timely warning of conditions that may lead to breakdowns.

Transcripts

These are scenes of avoidable and expensive disasters did they occur due

to bad design inadequate maintenance or incorrect operational procedures

experience shows that a large number of machinery breakdowns occur due to a

mistake in operation or maintenance of the alarm systems and the protection

devices yes engines generators boilers compressors

do break down sometimes fatally damaged because the alarm systems and the

protection devices monitoring them have been prevented from working sometimes

deliberately disconnected sometimes clogged up with paint and forgotten

abandoned without checking for long periods of time

this of course is asking for trouble when only a little attention to detail

by duty engineers could avoid an unforeseen incident resulting in

possible injuries of people major machine breakdowns upsetting the

commercial operation of the vessel leading to extra workload for ship's

personnel

once are less than meticulous checking and maintenance regime of the alarm

systems is allowed to develop onboard ship things can go wrong at any time the

ship's systems cease to be reliable because no one can be sure which alarm

is working and which is not

now what a blackened

this can occur as a direct consequence of neglecting the alarm system and

protection devices now the search begins what caused the blackout how long will

it take to get things going again why isn't the standby generator or the

emergency generators starting how long will it take to find the answer an

unscheduled event like this can cause consequential breakdowns as well let's

hope it's not too bad

unfortunately a ship cannot run on the basis of hope alone the engineers on

board ship must be sure that the alarm systems work properly at all times there

is no other way

let's leave this nightmare scenario now and look at a typical schematic view of

an alarm and protection system and its function a typical alarm circuit has a

censoring device such as a level sensor a thermocouple or pressure sensor these

are normally connected to display devices

which may have minimum and maximum values marked on them when these values

are reached a switch is activated and an electrical

or pressure signal is sent to the ship's alarm panels and audio-visual warning

devices the light on the panels will remain on or continue flashing until the

alarm has been acknowledged by the duty engineer and the condition which has

caused the alarm to activate is removed if it is a protection circuit as well as

a warning circuit the activation of the limit switch also initiates a shutdown

procedure of the affected machines that is the protection circuit activates one

or more switches or valves causing the protective machine to come to an

unscheduled halt but in a controlled manner this is how the system looks

using internationally recognized symbols

a typical example of this system operates on a main engine or on a

generator diesel the sensor may be a lube oil temperature or pressure sensor

or cylinder liner temperature sensor any one of these may indicate action devices

as well as some less important circuits

do you know which circuits on your ship are very important than which a less sir

if you came across a faulty sensor would you know if it was part of a

top-priority circuit or a relatively less critical one you need to know

all alarm and protection devices would protect the main propulsion engine and

the steering system are of top priority as are those on the power generation

plant and steam boilers these plants are vital components of ship's control any

breakdown or serious loss of these functions can be catastrophic for the

ship and its crew

still very important but not top priority are the alarms and protection

devices monitoring the air compressors air conditioning systems and

refrigeration systems they may not be as critical in the North Sea as they are in

the Gulf other systems such as cargo pump alarms or bow thruster alarms may

be low or high priority depending on the ship's working condition there are

warning only alarm systems which do not protect but warn of

potentially hazardous conditions arising these are normally level indicators or

temperature sensors in tanks and heating or cooling systems

now let's look at census starting with level indicators these monitor liquid

levels in fuel tanks lube oil tanks boilers and the like the simplest

systems are activated by the liquid itself the device is activated by the

level of the fuel rising or sinking a bath or below the set safety levels when

this occurs a sensor sends a signal to the warning devices coupled usually with

an indicator one of the most important level alarms onboard ship monitors the

boiler water level it is critical to maintain the right water level in

pointers especially in high pressure water tube boilers to ensure safe

operation a very dangerous situation can rapidly arise if the water quantity

inside the boiler is not maintained at the correct level there are visual level

indicators as well as alarm sensors monitoring the water level to check that

it is within set safety limits whilst we're dealing with boilers we must

mention a unique sensor and alarm circuit known as the flame out alarm

system a sudden loss of flame inside the boiler can lead to many undesirable

consequences therefore optical sensors flame eyes provide continuous monitoring

of the presence of flame and will give instant warning should the flame go out

the main propulsion engines alarm and protection devices can be looked at as

the most important ones onboard ship

on a typical diesel unit these employ temperature and pressure sensors which

monitor operational conditions to ensure optimum operation and effective

lubrication

for example the temperature sensors check the jacket cooling freshwater

outlet the lube oil inlet the fuel oil inlet and the reduction gear lube oil

inlet these are all of primary importance the pressure sensors monitor

the main lube oil inlet the reduction gear lube oil inlet the turbocharger

lube oil inlet and the cooling fresh water inlet among others these are all

part of the main engines protection system as well as providing warning

signals identical systems operate on other diesel engines such as those

driving the generators

because of their critical function these sensors must be tested regularly in

accordance with the ship's maintenance or test schedules ensuring accurate

function only sensors supplied with a valid certificate or assurance of

calibration should be installed and only calibrated test instruments must be used

for testing

here a temperature sensor is tested at both the minimum and maximum limits of

its operation

the quality control is on the measuring device attached to the testing

instrument

this one is using an oil bath with a controlled heating device and calibrated

thermometer

details of the test are recorded for future reference

the alarm setting can usually be read from the central monitoring system

provided that it can be demonstrated as operational this is done by resetting

the alarm to a normal value or by simulating an alarm value

but the most convenient method for this test is the use of a test pump and gauge

here a lube oil Inlet pressure sensor is tested with a precision testing

instrument

testing level alarms sometimes involves activating the alarm manually in this

case a builds well alarm and monitoring the response in accordance with the set

parameters

the test results should then be recorded for future reference

all these tests are most important to ensure that the monitoring system is

reliable at all times

the ship's manual will provide the necessary details for each test

applicable to the system's onboard

each engineer on board must know the alarm and protection systems thoroughly

including their relative importance to the ship's proper function each time an

alarm activates the duty engineer must be able to answer a number of critical

questions what does not alarm signify how important is the system to which it

relates what measures must be taken to eliminate the cause of the alarm

condition in what order should the countermeasures be executed

in conclusion it is essential that you know your ship's alarm system and

protection devices let you pay special attention to the critical alarm circuits

onboard ship that you always follow the alarm systems maintenance schedule and

ensure that all sensors and display systems are fully functional when an

alarm condition arises never press the reset without noting the cause of the

alarm if an adjustment must be made to temperature or pressure switches it is

essential that a calibrated instrument is used and direction of change is taken

into account for example when setting the starting pressure of a compressor

the setting should be the design figure with the pressure dropping when an

adjustment has been made always repeat the tests at different values no

adjustment should be permitted without checking at least two values afterwards

when an automatic restart circuit is involved in machine control it should

always be switched to manual and off before pressing reset to avoid the

machines starting automatically when reset equipment should never be

restarted or put back into service without rectifying the cause of the

alarm trip any abnormal run indication should always be investigated even if

the equipment is apparently running smoothly

the engineer on watch must have confidence in the alarm system and

protection devices in the engine room

he must be short all times that he will be given timely warning of any changing

condition which may lead to a breakdown so that he can take remedial action this

confidence is an essential component of good engineering practice