Small Vessel Engineering - Hydraulics & Pneumatics Past Questions

Produce a large amount of heat

Damage to pumps or oil boiling out of the tank

To prevent dirt from affecting the system

<p>Corrosion, rust, seizure, blocked filters</p> Signup and view all the answers

<p>Check oil regularly, trace the root cause, treat the system if possible</p> Signup and view all the answers

<p>To detect contamination</p> Signup and view all the answers

<p>Loss of control</p> Signup and view all the answers

<p>Regularly check system pipework, check oil via a laboratory</p> Signup and view all the answers

<p>Dirt, water, and air are three possible contaminants in a hydraulic system.</p> Signup and view all the answers

<p>Possible causes of dirt contamination include improper hygiene and flushing during commissioning, poor hygiene when filling the system, and through-life wear of system components.</p> Signup and view all the answers

<p>Possible causes of water contamination include condensation, leaking coolers, and contamination through system top-up.</p> Signup and view all the answers

<p>When a liquid contains undissolved air, system components can be affected.</p> Signup and view all the answers

<p>Dirt contaminants are prevented from affecting the system through proper hygiene and flushing during commissioning, use of filtration when filling the system, and maintaining system cleanliness during maintenance.</p> Signup and view all the answers

<p>Water contaminants are prevented from affecting the system by ensuring there are no sources of water leakage, such as from coolers, and by using proper filtration during system top-up.</p> Signup and view all the answers

<p>Air contaminants are prevented from affecting the system by ensuring the liquid does not contain undissolved air.</p> Signup and view all the answers

<p>Contaminants such as dirt, water, and air can negatively affect the performance and reliability of a hydraulic system by causing wear, corrosion, and other issues with system components.</p> Signup and view all the answers

<p>The five properties that enable a hydraulic fluid to fulfil its purpose are:1. Viscosity2. Lubricity3. Oxidation stability4. Thermal stability5. Corrosion inhibition</p> Signup and view all the answers

<ol> <li>Viscosity - Correct viscosity is important to ensure proper lubrication and minimized energy losses.2. Lubricity - Good lubricity prevents wear and tear on components.3. Oxidation stability - Stable against oxidation to maintain fluid properties over time.4. Thermal stability - Stable at operating temperatures to prevent degradation.5. Corrosion inhibition - Prevents corrosion of system components.</li> </ol> Signup and view all the answers

<p>Increasing the flow rate of the hydraulic oil will allow the pump to meet an increasing load from the system and develop the required pressure to maintain operation. This will enable the windlass to lift heavier loads, as the increased flow rate can match the increased demand.</p> Signup and view all the answers

<p>Changing the displacement of the hydraulic motor can alter the direction of the oil flow and therefore the direction of the windlass. It can also offer proportional speed control, as the amount the swash plate is moved from the neutral position will determine the speed of the windlass.</p> Signup and view all the answers

<p>A full system flush and laboratory test is needed at some stage to ensure the hydraulic fluid maintains its properties and the overall system is functioning optimally, even if the fluid can be used to temporarily get the system to an acceptable level for continued use. Regular maintenance and testing is required to prevent long-term issues.</p> Signup and view all the answers

<p>The purpose of a hydraulic fluid in a system is to transmit power, provide lubrication, and protect against wear and corrosion of the system components.</p> Signup and view all the answers

<p>Changing the displacement of the hydraulic motor can alter the direction of the oil flow, and therefore the direction of the windlass. It can also offer proportional speed control, as the amount the swash plate is moved from the neutral position will determine the speed of the windlass.</p> Signup and view all the answers

<p>Increasing the flow rate of the hydraulic oil will allow the pump to meet an increasing load from the system and develop the required pressure to maintain operation. This will enable the windlass to lift heavier loads, as the increased flow rate can match the increased demand.</p> Signup and view all the answers

<p>The speed will decrease, and the torque will increase.</p> Signup and view all the answers

<p>The angle of the swash plate alters the displacement of the pump, which in turn changes the flow rate of fluid through the system, thereby controlling the motor speed.</p> Signup and view all the answers

<p>Flow control valves, or variable orifices, control the rate of flow through to the motor, thereby regulating its speed.</p> Signup and view all the answers

<p>An air flow control valve uses control air to pneumatically operate a flow valve, which in turn regulates the flow rate to the hydraulic motor, thereby controlling its speed.</p> Signup and view all the answers

<p>Using a frequency drive for the electrical motor driving the pump allows for very fine control over the pump's speed, which in turn affects the flow rate and speed of the hydraulic motor.</p> Signup and view all the answers

<p>For a 10-mark question, it is typical to allocate 4 marks for the diagram and 6 marks for the description.</p> Signup and view all the answers

<p>The term &quot;orifice&quot; refers to a variable opening or restriction in a flow control valve that regulates the flow rate of hydraulic fluid.</p> Signup and view all the answers

<p>The hydraulic cylinder shown in Figure Q4 operates a safety barrier.</p> Signup and view all the answers

<p>Check valve 'D' allows the supply to fill the right side of the cylinder.</p> Signup and view all the answers

<p>The supply enters from the right port of valve 'A', leaves through the left port, enters the bottom of valve 'B', and opens check valve 'D' via the pilot line.</p> Signup and view all the answers

<p>The force exerted on the piston is equal to the pressure multiplied by the area: $Force = Pressure \times Area$.</p> Signup and view all the answers

<p>The piston 'E' moves to the right because the force on the left side (greater area) is higher than the force on the right side.</p> Signup and view all the answers

<p>The size of the ports in the valves roughly controls the speed of the piston 'E' by regulating the flow of fluid.</p> Signup and view all the answers

<p>When the piston 'E' moves to the left, the supply fills the right side of the cylinder via check valve 'D', and the left side of the cylinder is drained back to the tank through the left port.</p> Signup and view all the answers

<p>Valve 'B' is a 3-position valve that, when moved to the right in the cross-over position, allows the supply to be fed to the bottom of valve 'C' and opens check valve 'D' through the pilot line.</p> Signup and view all the answers

<p>The controlled movement of the piston 'E' is due to the difference in forces on the left and right sides, where the force on the left (greater area) is higher than the force on the right.</p> Signup and view all the answers