This module will look at the topic of hydraulics. It will cover the following topics;

  • Pressure and density
  • Head pressure
  • Suction
  • Vapour pressure
  • Effect of temperature on suction lift
  • Cavitation
  • Syphons
  • Pumps
  • Water power
  • Flow in pipies
  • Frictional loss
  • Height of effective jets
  • Output of nozzles
  • Jet reaction
  • Output of a water main
  • Archimedes principle

 

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Module 1

This module will give you an introduction to the subject of hydraulic principles.

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Module 2

This module will discuss atmospheric pressure and the principles of the inverted tube.

 

Module 3

This module will discuss the issue of head and pressure and how they are related.

 

 

Module 4

This module will discuss the topic of suction and how the vapour pressure is increased when a vacuum is created.

 

 

Module 5

This module will look at how temperature can affect suction lift.

 

 

Module 6

This module will discuss the issue of cavitation.

 

 

Module 7

This module will discuss the syphon and the principle of how it operates.

 

Module 8

This module will discuss brake power and water power

 

This module will go through some examples of determining brake power and water power.

 

Module 9

This module will discuss flow in pipes and hoses.

 

 

 

Module 10

This module will discuss the effective height of jets. Attempt these questions and then view the module.

1. Determine the effective height of a jet from a 25mm nozzle operating at 3.5 Bar?
2. Determine the effective height of a jet from a 18mm nozzle operating at  4 Bar?
3. What would be the impact of changing the nozzle to 25mm and still maintaining the same pressure at the nozzle?

 

 

Module 11

This module will discuss frictional losses. Attempt the following questions and then view the module.

1. A pump is supplying a branch at 5 bar pressure.  The branch is at the end of 6 lengths of 25m hose which has a diameter of 70mm and a friction factor of 0.0013. If the velocity of water is 8 m.sec. what pressure is required at the pump?

2. A pump is supplying a branch at 4.5 bar pressure.  The branch is at the end of 4 lengths of 25m hose which has a diameter of 45mm and a friction factor of 0.0012.  If the velocity of water is 6 m.sec what pressure is required at the pump?

3. A pump is supplying a branch at 4 bar pressure.  The branch is at the end of 5 lengths of 25m hose which has a diameter of 45mm and a friction factor of 0.001.  If the velocity of water is 4 m.sec what pressure is required at the pump?

4.  What would happen if you halve the velocity in the hose in the previous question?

5.  Water is flowing through 120metres of 45mm hose at a velocity of 5m second.  The pressure at the pump is 7.5 bar and it has been identified that 15% of the pressure is lost between the pump and the nozzle.

•a) Explain firstly the purpose of the nozzle?
•b) Secondly why pressure is lost and its value?

 

 

 

Module 12

This module will discuss frictional losses. Attempt the question and then view the module.

1. A pump is supplying 650 litres .minute of water through 4 lengths of 25m hose with a diameter of 70mm and a  friction factor of 0.004. The pressure at the pump is 7.5 Bar, what is the pressure at the branch?

2. A pump is supplying 400 litres .minute of water through 4 lengths of 25m hose with a diameter of 45mm and a  friction factor of 0.001. The pressure at the pump is 6 Bar, what is the pressure at the branch?

 

 

 

Module 13

This module will discuss frictional loss. Attempt the questions and then view the module.

1. The pump is supplying 650 litres /minute of water through 4 lengths of 25m hose with a diameter of 45mm and a  friction factor of 0.001.  The pressure at the pump is 6 Bar, what is the pressure at the branch?

 

This module will go through some examples of determining brake power and water power

 

 

 

Module 14

Attempt the following questions and then view the module.

1. A pump is supplying 500 litres.minute of water through 5 lengths of 25m hose with a diameter of 45mm and a  friction factor of 0.002. The pressure at the pump is 7.5 Bar, what is the pressure at the branch?

 

 

 

Module 15

Attempt the following question and then view the module.

1. A pump is supplying 720 litres .minute of water through 3 lengths of 25m hose with a diameter of 70mm and a  friction factor of 0.003.  The pressure at the pump is 6 Bar, what is the pressure at the branch?

 

 

 

Module 16

Attempt the follwoing question and then view the module.
1. A 45mm hose is accidentally connected to a 70mm hose on the fireground, what will be the pressure loss due to doing this if 1650 litres minute are flowing.

 

 

 

Module 17

This module will discuss how to determine the output if a nozzle. Attempt the following questions and then view the module.

1. Determine the output from a 25mm nozzle operating at  4 Bar?

2. Determine the output from a 20mm nozzle operating at 3.5 Bar?

3. Determine the output from a 25mm nozzle operating at 4.5 Bar?

4. Determine the output from a 15mm nozzle operating at 5 Bar?

 

 

Module 18

This module will discuss jet reaction. Attempt the question and then view the module.

1. Determine the jet reaction from a 20mm nozzle operating at 4 Bar?

2. Determine the jet reaction from a 15mm nozzle operating at 4.5 Bar?

3. What would be the impact if we used a 30mm nozzle instead of a 15mm nozzle at the same pressure?

 

 

 

Module 19

This module will discuss how to determine the output of a water main. Attempt the question and then view the module.

1.  A firefighter connects a standpipe to a 125mm pipe.  The pressure gauge reads 4 Bar when the hydrant is opened.  Then a hose is run out and a nozzle fitted with water flowing at 1000 litres minute. The pressure when the water is flowing is 2.8 Bar

Determine the maximum output of the main?

2. A firefighter connects a standpipe to a 200mm pipe.  The pressure gauge reads 5 Bar when the hydrant is opened. Then a hose is run out and a nozzle fitted with water flowing at 1850 litres minute. The pressure when the water is flowing is 3.6 Bar

Determine the maximum output of the main?

3. A firefighter connects a standpipe to a 150mm pipe.  The pressure gauge reads 2.8 Bar when the hydrant is opened. Then a hose is run out and a nozzle fitted with water flowing at 987 litres minute. The pressure when the water is flowing is 1.76 Bar

Determine the maximum output of the main?

 

 

Module 20

This module will discuss how to determine archimedes principle.

 

 

Module 21

Attempt the following questions and then view the module.

1.  A 7kg metal ball is thrown into a tank of water and displaces 4kg of water.  What is the density of the metal ball?

2. A wooden box is placed in a tank of water.  The box is 1m x 1m x 0,5m deep. The box weighs 3kg.  At what height will the water reach?

 

 

 

Module 22

Attempt the following questions and then view the module.

A young boy blows up a crisp packet to a volume of 500cm3 and seals it up.  They then force it into a swimming pool, what force would be required to hold it under the water (you can ignore the mass of the crisp packet)?

 

Module 23

Attempt the following questions and then view the module.

Two cylindrical oil tanks are surrounding by a bund with an inner measurement of 80 metres x 35m x 8m high.  The diameter of one of the cylindrical tanks is 28m and the other is 24.5m.

The bund is half full of water and is in need of repair.  The Fire Service have been asked to empty the bund and uses three pumps.  All of the pumps have twin lines operating with 20mm nozzles and at a pressure of 4.5 bar.

How long will it take?