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A short class with Sarah and her students. The other ways are under More.
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Today, we will explore how double acting steam hammers operate. Can anyone explain what happens during the upward stroke?
Air is supplied to the lower cylinder, which pushes the hammer up.
Correct! And what happens to the air that was already in the upper cylinder?
That air gets expelled through the exhaust!
Right! Now, who can tell me how the downward stroke is initiated?
We supply air to the upper cylinder, pushing the hammer back down.
Excellent! The dual operation allows these hammers to be quite efficient. Remember, it's crucial for understanding their advantages over other types of hammers.
Let's talk about why using steam energy is advantageous. Why can double acting hammers be lighter than other hammers?
Because they derive most of their blow energy from steam, right?
Exactly! Since they don't rely solely on the hammer's weight, they can be designed to be more compact. What types of soil do you think they are most suitable for?
They’re great for light to medium weight piles in normal soil conditions.
Correct again! However, are there situations where we should not use these hammers?
Yes, they shouldn’t be used in high-friction or tough soil conditions.
Indeed! It’s important to recognize when these advantages turn into disadvantages.
As we know, while these hammers are effective, they do have limitations. Can anyone tell me why double acting hammers are not recommended for concrete piles?
Because the high blow rate could damage the concrete piles?
Exactly! They have a blow rate of 95 to 300 blows per minute, which is excessive for concrete. What types of piles are they better suited for?
Lighter piles in normal soil conditions, like steel or wooden piles.
Correct! Understanding both the advantages and limitations is key when choosing a hammer for pile driving.
Explains how air is supplied alternately to drive the hammer up and down.
Emphasizes the efficiency gained from steam power, allowing for lighter designs.
Indicates the frequency of impacts by the hammer and the implications for suitability in pile types.
Up and down, the hammer goes, steam in charge, everyone knows.
Once upon a time, a little hammer loved to jump up and down, thanks to steam! It could drive piles into the ground without excessive weight, making it a champion in the construction field.
S - Steam Energy, E - Efficiency, L - Lighter Design for double acting hammers.
SHAPE - Steam, Hammer, Air, Pile, Efficiency.
Term
Double Acting Hammer
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Term
Blow Rate
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A type of hammer that uses both upward and downward strokes powered by air or steam to drive piles into the ground.
The number of blows per minute that a hammer can deliver, indicative of its efficiency and suitability for different applications.
Energy derived from steam, which is utilized in powering the hammer strokes of a double acting steam hammer.
The resistance faced by a pile when being driven into the soil, significantly affecting the efficiency of pile driving.
This section outlines the advantages of double acting steam hammers, highlighting their efficient operation, suitability for various soil types, and limitations.
The advantages of double acting steam hammers include their reliance on steam energy, allowing for lighter hammer designs and shorter strokes. However, they are less effective in high friction soils and should not be used for concrete piling due to their high blow rates, which can cause damage. Their compact nature and high blow rate make them ideal for driving light to medium weight piles into normal soil conditions.
In the operation of double acting steam hammers, two cylinders are employed to alternately lift and drop a hammer. The process begins with air being supplied to the lower cylinder, pushing the hammer upward, while the air in the upper cylinder is expelled. This upward stroke is followed by supplying air to the upper cylinder to push the hammer back down into the lower cylinder. The most significant advantage of this system is its efficient use of steam energy, which accounts for approximately 90% of the blow energy, allowing lighter hammers to be utilized and achieving greater compactness compared to single acting hammers.
These hammers are designed for light to medium weight piles and are suitable for soil with normal frictional resistance. However, they are not intended for tough soil conditions or for driving concrete piles due to the excessive blow rates of 95-300 blows per minute, which could damage concrete. Therefore, double acting steam hammers are particularly beneficial in situations where energy efficiency and reduced hammer weight are critical.