S&S Marine Tech.

14/03/2024

22/09/2023

Do you know the different types of rudders used on ships?

Check out our post to find out!

What kind of rudder does your ship use? Comment below

Read more articles on ship construction from our mobile app.

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17/04/2023

Marine Insight - The maritime industry guide.

08/05/2022

12/04/2022

The ballast tanks are water tanks introduced at various locations of the ship.

They are basically dedicated to carrying water for maintaining ship stability during the sea voyage.

Each ship type has a different construction of a ballast tank. Check out our post to find out.

Let us know in the comments what arrangement of ballast tanks have you seen onboard your ship?

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Download our eBook on Deck Machinery Operations.

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04/02/2022

A ship at sea is subjected to a number of forces causing the structure to distort.

Check out our post to find out some important stresses a ship is exposed to.

Let us know in comments what other stresses are ships subjected to.

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26/01/2022

➡️The most common system for measuring water depth, and preventing collisions with unseen underwater rocks, reefs, etc., is the echosounder. 📠

👉🏻These sonar systems use a transducer that is usually mounted on the bottom of a ship.🛳

🎼 Sound pulses are sent from the transducer straight down into the water.

↥ The sound reflects off the seafloor and returns to the transducer. The time ⏰ the sound takes to travel to the bottom and back is used to calculate the distance to the seafloor.

🚨Check out our post to find out the working of Echosounder.

🗣Let us know in comment if you liked this post. For more such maritime related content, visit https://buff.ly/3poWimD

25/01/2022

Every ship at sea needs to display certain day and night signals in order for other ships to identify them
Check out our post to find out the different day and night signals of ships at sea.

Let us know in comments if you found this post helpful

For more such maritime-related content, visit https://bit.ly/3evB3I3

03/01/2022

08/12/2021

Bulbous bow is a peculiar bulb like projection at the forward end of the ship. Learn about the significance of this ship structure and the importance of its design inside the article.

08/09/2021

Custom built this cage and strut.

05/09/2021

31/08/2021

18/08/2021

Venturi-meter Introduction, Working Principle, Applications, Advantages and Limitations

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It is a device used to measure flow rate of fluid like gases, liquids and matter like slurry, by using static pressure head difference between throat and its inlet.





1.Converging Section

2.Throat

3.Diverging Section

Converging Section:

This section is inlet of venturi-meter and attached to the the pipe.Its purpose is to gradually reduce the static pressure and increase the velocity (dynamic pressure) of fluid which is accomplished by gradually decreasing the area. converging cone angle 15-20 degree and its length is 2.7 (D1-D2)

Throat Section:

It is the middle section of venturi-meter of constant minimum cross sectional area.Its purpose is to maintain the lowest pressure head for short interval of time. its diameter is 0.3 - 0.75 times the inlet pipe diameter

Diverging Section:

This is last section of venturi-meter and attached to pipe. Its purpose is to gradually reduce the velocity (dynamic pressure) and increase the static pressure of fluid which is accomplished by gradually increasing the area. Diverging cone angle is about 5 - 7 degrees and its length is three to four times then that of converging cone to avoid back flow (vortex) formation in the consequence of adverse pressure gradient

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Venturi-meter work on the basis of Bernoulli and Continuity equations



Static Pressure + Dynamic Pressure + Pressure Head = Total Pressure

(Bernoulli equation)

by considering horizontal geometry of venturi-meter " Pressure Head" remain same and has no effect on pressure variation, So it can be neglected to understand working principle. So Bernoulli equation can be written as

Static Pressure + Dynamic Pressure= Total Pressure

(Bernoulli equation)

Volume Flow Rate = Cross Sectional Area of Venturi * Velocity of Fluid

(Continuity equation)

Role of Continuity Equation: (Mass Conservation)

When flow enter in converging part its cross sectional area decreases. In order to hold law of mass conservation, volumetric flow rate should remain same, hence according to continuity equation velocity of fluid increases.

Role of Bernoulli equation: (Energy Conservation)

In the consequence of increase in velocity dynamic pressure increases while static pressure decreases correspondingly. As the total pressure energy should remain same according to law of conservation of energy.

So the static pressure difference is created between Inlet and Throat of Venturi-meter which can be measured in form of pressure head by attaching Manometer to the end of both inlet and throat tappings.

Once the pressure head difference is measured Flow rate of fluid can be measured by using fallowing formula

Where

Q = Flow Rate

A1 = Inlet Area

D1 = Inlet Diameter

D2 = Throat Diameter

H = static Pressure Head Difference

g = Gravitational Acceleration

Cd = discharge coefficient ( its value is less then unity and given by venturi-meter supplier)

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In Automotive industry it is used to measure the fuel and air distribution in carburetor

In Medical field it is used to measure the Volume flow of blood through vessels.

In Chemical industry it is used to measure the Flow rate of chemical through pipes.

Flow rate of water is measured by venturi-meter in water supply system

In pneumatic based machine it is used vacuum pumps

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It doesn't have any moving parts so no maintenance is required

Capable to measure flow rate of wide range of fluids under various operating conditions

Adopt Pressure recovery challenges

It has high discharge coefficient (Can be used to measure high flow rate)

It is very Precise

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It require large space for installation

In order to avoid turbulence for precise measurement, straight pipe of fair length is require to which venturi-meter is attached. So it is not suitable for pipe having bends or misalignment.

16/07/2021

It is proven that over time the ship's steel in its structure deteriorates. Here is an illustration on what are the things to be checked within the ship's tanks, namely cargo tanks (dry and wet), ballast tanks, void spaces, fuel oil tanks, freshwater storage tanks, etc.
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16/07/2021

09/02/2021

Learn about marine propeller shaft and its various components, along with their design, construction and working mechanism.