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Learn it your way
A short class with Sarah and her students. The other ways are under More.
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Today, we will discuss the double acting steam hammer. Can anyone tell me what they think a steam hammer does?
I think it’s a machine that uses steam to do some kind of work, maybe in construction.
Exactly! The steam hammer is used mainly for driving piles into the ground. It consists of two cylinders: an upper and a lower. Both cylinders are crucial to its operation, which you will learn about shortly.
How does it work with those two cylinders?
Great question! When we supply air to the lower cylinder, it pushes the hammer upwards into the upper cylinder. Who can tell me what happens to the air in the upper cylinder then?
The air gets pushed out, right?
Yes! The air is expelled through an exhaust. This mechanism allows for continuous striking, which is essential for driving piles effectively. To remember this, think of the acronym 'LAY' - Lift, Air, Yield.
So LAY helps us think about how air is used to make the hammer lift and strike?
Exactly, 'LAY' encapsulates the operation! Remember, these hammers are designed for lighter conditions when driving piles into soil.
Now, let's talk about energy. What type of energy drives the hammer during its strokes?
Is it steam energy?
Correct! Approximately 90% of the blow energy comes from steam energy. This high reliance on steam means we can use lighter hammers. Can anyone think of why that’s beneficial?
Maybe it makes it easier to move and operate?
Yes, yes! Lighter hammers mean we don’t need as much force to lift them, making the operation more efficient. Remember: lighter hammers, higher efficiency. This relationship crucially affects how deep we can drive the piles.
What kind of soil works best with these hammers?
Excellent question! They work best in light to medium weight piles and soils with normal frictional resistance. Never use them in high frictional soils or for concrete. What would happen if we did?
The concrete could crack or break!
Exactly! Damage can occur due to the high blow rate, which can be between 95 and 300 blows per minute. Let’s remember this with 'HFC' – High Friction Concrete, to avoid where these hammers should not be used.
Having covered how the steam hammer works, can anyone summarize the advantages of using it?
It’s compact and doesn’t require heavy weights, plus it operates with high energy efficiency!
Right! It's designed for lighter applications. And because it delivers quick successive blows, it’s efficient in appropriate conditions. What are some cases where using this hammer could be problematic?
When you’re dealing with heavier soils or concrete piles, right?
Absolutely! Suitable soil conditions are crucial. High friction can lead to failure. To make sure we remember this, let's use 'LMC' - Lighter Material Concrete – so we know to avoid that.
Sounds good, LMC helps us remember the limitations!
Great teamwork! Let’s summarize: the double acting steam hammer thrives in lighter conditions, provides high blow rates, and should be used cautiously to avoid damaging structures.
The mechanism consists of two cylinders that alternate the supply of air or steam to move the hammer.
90% of the blow energy comes from steam, allowing the use of lighter hammers.
Ideal for light to medium weight piles in soils with normal friction resistance and not recommended for concrete or high friction soils.
Lift, air in, and hammer goes, striking high, while down it flows.
A construction team uses a light hammer powered by steam, easily lifting and striking for efficient piling on a sunny day.
LAY – Lift, Air, Yield helps remember the key operational phases.
HFC - High Friction Concrete, remembering where the double acting steam hamers should never be used.
Term
What is the primary energy source for a double acting steam hammer?
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Term
What is the blow rate of a double acting steam hammer?
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A mechanical device that uses compressed air or steam to drive a hammer up and down for driving piles.
The components within the steam hammer where air or steam is supplied to move the hammer.
The frequency at which the hammer strikes, measured in blows per minute.
The force opposing the motion of the hammer as it interacts with the soil.
The double acting steam hammer utilizes compressed air or steam to drive a hammer up and down for driving piles into the ground efficiently, particularly in lighter soil conditions.
The double acting steam hammer operates with two cylinders where air is alternately supplied to raise and lower a hammer. This mechanism allows for a high blow rate and the use of lighter hammers, making it suitable for driving light to medium weight piles into soils with normal friction resistance. However, it is not suitable for heavier soils or concrete piles due to the potential for damage.
The double acting steam hammer is a mechanical device consisting of two cylinders (upper and lower), which work in tandem to lift and lower a hammer for pile driving. In operation, compressed air is introduced into the lower cylinder, pushing the hammer upward into the upper cylinder, while the air in the upper cylinder is expelled through an exhaust valve. In the subsequent downward stroke, air is supplied to the upper cylinder, again pushing the hammer down while expelling air from the lower cylinder.
This mechanism highlights that approximately 90% of the blow energy is derived from steam energy, allowing for the use of lighter hammers and shorter strokes compared to single acting hammers. While effective for driving light to medium weight piles, these hammers are designed for use in soils with normal frictional resistance and should not be used in high-friction clay or for concrete piles due to their high blow rate (95 to 300 blows per minute), which could cause damage.
In essence, the double acting steam hammer is notable for its compact design, lightweight construction, and high operational efficiency in appropriate soil conditions.