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A short class with Sarah and her students. The other ways are under More.
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Today, we're going to explore the double acting steam hammer. Can anyone tell me how it operates?
Is it because of the air pressure in the cylinders?
Correct! The hammer operates by alternating air pressure into the upper and lower cylinders. When air is supplied to the lower cylinder, the hammer is pushed upward into the upper cylinder, expelling the air.
What happens when the hammer goes down?
Good question! When we supply air to the upper cylinder during the downward stroke, it pushes the hammer downwards, expelling air from the lower cylinder. This mechanism enables continuous motion.
So, the air pressure controls the movement?
Exactly! Remember the acronym 'AIR' - 'Accelerate Incremental Rebound.' It's a way to remember that air pressure accelerates the hammer's movement.
What two main factors affect how the hammer operates?
The two main factors are the supply of steam energy and the type of soil conditions it is designed for. Now, let’s summarize: the hammers work by pressure variation and are designed for lighter conditions.
Let’s dive into the energy dynamics of the double acting hammer. Who can tell me what energy source it primarily relies on?
Steam energy!
That's right! About 90% of the blow energy comes from steam energy. This means we don't need a heavier hammer for impact. What benefits does this bring?
We can use lighter hammers!
Exactly! Lighter hammers are easier to manage and can perform better in specific conditions. Who remembers what those conditions are?
They are suitable for light to medium-weight piles and normal soil conditions.
Right! Remember, these hammers should never be used on heavier or very compact soils like hardened clay because they might not perform effectively. Summary: steam energy allows for lighter hammers in suitable soil.
Now, let's focus on the limitations of our double acting hammer. Can anyone share a situation where this hammer might not be suitable?
If the soil has high friction, like clay?
Exactly! High-friction soils can hinder operation efficiency. Additionally, why should we avoid using these hammers on concrete piles?
Because of the high blow rate that can damage them!
Yes! High blow rates, averaging 95 to 300 blows per minute, could lead to structural damage. When should we prefer it instead?
For driving light to medium-weight piles in normal soil!
Great job! In summary, use this hammer for lighter conditions and avoid it for heavy or concrete applications.
Understanding how the hammer transitions between upward and downward motions based on air pressure.
The significant role of steam energy in providing the majority of the operational power.
Recognizing the soil and application conditions that are appropriate or inappropriate for a double acting steam hammer.
Air in the chamber, hammer up and down, driving piles without a frown.
Once, in a construction site, a double acting hammer danced, pushing its pile up with all its might, only to push it down in its next chance.
A.R.I. - Air, Rebound, Impact: key components in the hammer's operation.
DASH: Double acting steam hammer is for Driving, Alternating, suitable for lighter conditions with Set high blow rates.
Term
How does a double acting steam hammer operate?
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Term
What is the blow rate of a double acting steam hammer?
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A type of hammer that operates using air pressure in cylinders to drive a hammer up and down alternately.
The number of blows delivered per minute by the hammer during operation.
The resistance encountered by a pile as it penetrates the soil, affected by soil type and condition.
Energy derived from steam that is harnessed to provide power for the hammer's operation.
This section explains the operational limitations of a double acting steam hammer, including appropriate usage scenarios and energy dynamics.
The section covers how a double acting steam hammer operates with upward and downward strokes, the energy derived from steam, and the limitations regarding its usage, particularly in terms of soil and pile types. It emphasizes that these hammers are designed for lighter applications and should not be used on very heavy or concrete piles due to their high blow rates.
This section discusses the operational mechanics of the double acting steam hammer, illustrating its reliance on steam or compressed air to perform its functions. The upward and downward strokes are achieved by supplying air into the lower and upper cylinders, respectively, effectively alternating the hammer's position. During the upward stroke, the hammer is propelled upward by air introduced into the lower cylinder, while air from the upper cylinder is expelled. Conversely, during the downward stroke, air is supplied to the upper cylinder, pushing the hammer down and expelling air from the lower cylinder.
Most of the blow energy during operation is derived from steam energy, allowing for the design of lighter hammers, which are advantageous for lighter conditions, such as driving light to medium-weight piles into normal soil. However, the double acting hammer is not suitable for very high frictional resistance soils, like tight clay, or for driving concrete piles, due to the potential for damage caused by its high blow rate of 95 to 300 blows per minute. Thus, while the hammer offers efficiency and compactness, it is crucial to acknowledge its operational limitations in specific conditions.