Auxiliary 1 hydraulics Flashcards
(10 cards)
List SIX examples of contaminants that may be found in hydraulic oil.
- Water & dirt contamination from vents and fill points.
- Sea water contamination from leaking cooler
- Metallic particles from wear
- Elastomers from damaged seals
- Fibers from cleaning material
- Rust particles from internal corrosion
state 3 reasons that may cause a relief valve to fail to lift should excessive pressure occur (3)
Here are three reasons a relief valve may fail to lift under excessive pressure:
- Valve Blockage – Debris or contamination in the valve can obstruct its operation, preventing it from opening.
- Incorrect Calibration – If the valve’s set pressure is improperly adjusted, it may not activate at the intended pressure level.
- Spring Failure – A weakened or broken spring can prevent the valve from responding to pressure changes effectively.
Describe the operation when manual valve is moved to each of the following
A) The straight through position
B) The cross-over position
The dogs of a shell door are open and closed using a munually operated hydraulic cylinder. Using the sketch below, sketch a system diagram for the cylinder using standard hydraulic symbols
With reference to hydraulic systems
Describe how the system is checked for water contamination after an extender period of shut down.
- take a sample and let it sit it and should seperate
- pop test, drop a bit of oil on a hot pan
- Water find paste
Expain when a pulsation damper may be fitted to the delivery line describe how it works.
A pulsation damper is fitted to the delivery line of a pump when there is a need to reduce pressure fluctuations and ensure smooth fluid flow. It is commonly used in positive displacement pumps, where pulsations can cause vibration, noise, and system inefficiencies.
When It Is Used
- High-pressure systems – Prevents pressure spikes that could damage components.
- Metering & dosing applications – Ensures consistent flow for precise fluid delivery.
- Long pipeline systems – Reduces hydraulic shock and minimizes wear on pipes.
- Sensitive equipment protection – Prevents pulsations from affecting downstream instruments.
- state the purpose of fitting isolating valves in a ring main (firemain)
- state the type of valve that should be fitted for isolating sections of a ring main
- explain why the type of valve stated in (2)is used
- state how it is ensured the isolating valve will operate when required
- state the position of the machinery space isolating valve.
1. Purpose of Fitting Isolating Valves in a Hydraulic Ring Main
Isolating valves are installed to:
- Allow Sectional Isolation – Enables maintenance or repairs without shutting down the entire system.
- Enhance Safety – Prevents uncontrolled fluid flow in case of leaks or failures.
- Improve System Control – Helps regulate pressure and flow distribution efficiently.
2. Type of Valve for Isolating Sections of a Ring Main
A ball valve is typically used for isolation due to its ability to provide a full shut-off when required.
3. Why This Type of Valve is Used
- Ball Valve – Offers quick shut-off with minimal pressure drop and is highly reliable. there are compact in size and readly aviable.
4. Ensuring the Isolating Valve Operates When Required
- Regular Maintenance & Testing – Periodic checks ensure functionality.
- Actuator or Manual Control – Valves may be equipped with actuators for remote operation.
- Position Indicators – Visual or electronic indicators confirm valve status.
5. Position of the Machinery Space Isolating Valve
The isolating valve for the machinery space is typically located outside the machinery space in an accessible and tenable position, ensuring safe operation in case of emergencies.
state the results of using a hydraulic oil having each of the following properties.
- too high a viscosity
- too low a viscosity
Too High Viscosity
- Sluggish System Response – Thick oil slows movement and reduces efficiency.
- Increased Mechanical Friction – Causes excessive wear on components.
- Cavitation Risk – Poor flow can lead to air pockets and system damage.
- Heat Generation – Higher resistance increases operating temperatures.
Too low of Viscosity
- Reduced Lubrication – Inadequate film thickness leads to increased wear.
- Internal Leaks – Thin oil may bypass seals, reducing system efficiency.
- Pump Overheating – Excessive friction causes heat buildup.
- Loss of Power Transmission – Poor viscosity affects pressure stability.
With reference to control systems
State five advantages of using pnuematics
state five advantages of using hydraulics
Advantages of Using Pneumatics in Control Systems
1. Clean & Safe Operation – Uses air, eliminating contamination risks.
2. Cost-Effective – Components are generally cheaper and require less maintenance.
3. Fast Response Time – Air compresses and moves quickly, enabling rapid actuation.
4. Simple Design – Fewer components make installation and operation straightforward.
5. No Risk of Fluid Leaks – Unlike hydraulics, air leaks do not cause environmental hazards.
Advantages of Using Hydraulics in Control Systems
1. High Power Density – Can generate immense force in a compact system.
2. Precise Control – Provides smooth and accurate movement, ideal for heavy machinery.
3. Consistent Performance – Maintains steady force output without power fluctuations.
4. Versatile Applications – Used in industries ranging from construction to medical equipment.
5. Durability & Longevity – Hydraulic systems have fewer moving parts, reducing wear and tear.
Fig below shows a hydraulic cylinder that operates a safety barrier. Explain the possible
Consequences of EACH of the following:
(a) Dirt in the hydraulic oil
(b) Orifices being adjusted to be too large
a) Wear of the piston cylinder, and seals. Obstuction of the orifices preventing the check valves seating properly.
b) if the orifices are too large the speed control of operation will be affected which could result in accidents as the flow of oil out of rams will be too fast. The speed of the operation will put servere stress on the pivot point where the ram is attached possibly causing fractures due to cyclic stress.
