Professional Courses
Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Categories
Interactive Games
Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.
Typing
Memory
Math
English Adventures
Knowledge
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Double Acting Steam Hammer - Mechanism
Unlock Audio Lesson
Today, we're going to explore how a double acting steam hammer works. Can anyone tell me what the main components are?
It has two cylinders, right? An upper and a lower one.
Exactly! When we supply air to the lower cylinder, what happens next?
The hammer goes up into the upper cylinder!
Great! And what happens to the air in the upper cylinder?
It's expelled out through the exhaust.
Right! So this process repeats for the downward stroke as well. Can anyone recap this mechanism?
We push the hammer up with air in the lower cylinder and then push it down with air in the upper cylinder!
Perfect! Remember, we can use the acronym 'UP-DOWN' to recall this process: air in the 'UP' lower cylinder, and air in the 'DOWN' upper cylinder.
Energy Source
Unlock Audio Lesson
Now, let's talk about energy. Do you know where most of the energy for the double acting steam hammer comes from?
Is it from the weight of the hammer?
Good thought, but most energy comes from compressed air or steam, about 90%!
So, lighter hammers can be used because they don’t rely on weight?
Exactly! Lighter hammers are not only efficient but also designed for specific soil types. What's an example of where they shouldn’t be used?
Concrete piles!
Very good! Remember, if you're using high blow rates, you need to be cautious with concrete to prevent damage.
Application of Diesel Hammers
Unlock Audio Lesson
Now, let's find out how diesel hammers operate. What’s unique about the diesel hammer setup?
It's self-contained, so it doesn’t need separate equipment.
Excellent! How does the process start?
You lift the ram and then let it fall.
Correct! As it falls, what happens with the fuel injection?
The fuel pump sprays fuel into the combustion chamber!
Exactly! And what’s the benefit of this explosive energy?
It drives the pile and lifts the hammer back up for the next stroke!
Right! This energy use allows for efficient operation, especially in cohesive soils.
Soil Conditions and Hammer Types
Unlock Audio Lesson
Let's discuss soil conditions. Which hammer type is suitable for normal soils?
The double acting steam hammer!
Correct! And what about the diesel hammer?
It works better in cohesive soil.
Exactly! Cohesive soils provide better resistance, resulting in a better stroke. What happens with too much resistance?
The cycle can stop if the soil is too tough.
Great connection! Always remember the relationship between hammer type and soil resistance when planning your projects.
Introduction & Overview
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
Quick Overview
Standard
The activation and energy generation of double acting steam hammers and diesel hammers are explained in detail. Key points include the upward and downward strokes of the steam hammer, energy derivation from steam, suitable soil conditions for various hammers, and the operational advantages of diesel hammers compared to steam hammers.
Detailed
Activation and Energy Generation
In this section, we delve into the mechanisms behind double acting steam hammers and diesel hammers, essential devices for driving piles into the ground.
Double Acting Steam Hammers
- Mechanism Overview: The double acting steam hammer consists of two cylinders—an upper and a lower cylinder. For the hammer's upward stroke, air is introduced into the lower cylinder which raises the hammer and expels air from the upper cylinder through an exhaust. Conversely, during the downward stroke, air enters the upper cylinder, pushing the hammer down while expelling air from the lower cylinder.
- Energy Source: Both upward and downward strokes derive 90% of their blow energy from compressed air or steam, allowing for lighter hammers to be used instead of relying solely on weight. These hammers are suitable for light to medium weight piles and are not suitable for concrete piles due to their high blow rates (95 to 300 blows per minute), which can damage concrete.
- Application Scope: These hammers are designed for soils with normal frictional resistance and should not be used in very tight clay or for heavy piles, as they are optimized for lighter conditions.
Diesel Hammers
- Self-Contained Unit: Diesel hammers are compact, integrating all components within a single unit requiring no separate compressors or boilers. This feature enhances mobility on construction sites.
- Operational Mechanism: The operation starts by lifting the ram with any mechanism, such as a crane, allowing it to fall. As it descends, it activates a fuel pump that injects fuel into a combustion chamber, where the air-fuel mixture is compressed to induce ignition. This not only drives the pile downward but also allows for a rebound action enabling continuous operation without reintegration by external means.
- Soil Adaptability: Diesel hammers perform better in cohesive soils where driving resistance and the resulting rebound of the hammer are enhanced. The key operational advantage lies in the double effective blow energy due to combustion, making them viable for various soil types, including tougher conditions.
Conclusion
Understanding these mechanisms is crucial for selecting the appropriate hammer type for specific soil conditions and project requirements.
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Upward Stroke of the Double Acting Hammer
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
In the upward stroke, air is supplied into the lower cylinder, pushing the hammer into the upper cylinder. The air that was already in the upper cylinder is expelled through the exhaust.
Detailed Explanation
In the first part of the operation of a double acting hammer, we focus on the upward stroke. This begins when compressed air is introduced into the lower cylinder. As the air fills this cylinder, it exerts pressure, which forces the attached hammer upward into the upper cylinder. At the same time, air that was previously in the upper cylinder needs to escape; therefore, it is pushed out through an exhaust outlet. This process effectively raises the hammer and completes the upward stroke.
Examples & Analogies
Imagine a balloon filled with air representing the lower cylinder. When you push down on the balloon, the air will push up against anything above it. In this analogy, the hammer is like an object above the balloon, rising as you compress the air inside it.
Downward Stroke of the Double Acting Hammer
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
During the downward stroke, air is supplied to the upper cylinder, pushing the hammer back into the lower cylinder. Air in the lower cylinder is expelled through the exhaust.
Detailed Explanation
The downward stroke operates similarly to the upward stroke, but in reverse. Now, air is supplied to the upper cylinder instead. This air pressure forces the hammer to move downward back into the lower cylinder. As the hammer descends, the air that was originally in the lower cylinder is pushed out through the exhaust. This cyclical process of alternating air supply between the two cylinders allows for continuous hammering action.
Examples & Analogies
Think of a seesaw on a playground. When one end goes up (the upward stroke), the other end must go down (the downward stroke). The action of pushing air into one cylinder causes the hammer to rise, while filling another cylinder causes it to descend, similar to how a seesaw works.
Energy Source for Double Acting Hammer
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Most of the blow energy for both strokes is derived from steam energy. About 90% of the blow energy comes from the action of air or steam.
Detailed Explanation
The operation of the double acting hammer relies predominantly on steam energy to create its blow energy. During both the upward and downward strokes, the energy generated is leveraged from the pressurized air or steam. This means that instead of requiring heavy weights for the hammer to perform effectively, the energy provided by the steam is sufficient, allowing the hammer to be lighter and more efficient.
Examples & Analogies
Think of riding a bicycle. Instead of using your full body weight to push the bike forward (heavy weights), you use smooth pedaling (steam energy) to keep the bike moving. Just as a cyclist relies on their pedaling efficiency rather than just their body weight, the hammer uses steam energy for its operation.
Design Specifications of the Double Acting Hammer
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Double acting hammers are designed for lighter conditions, suited for light to medium weight piles and soils with normal frictional resistance. They are not suitable for concrete piles due to their high blow rate.
Detailed Explanation
The design of double acting hammers accommodates lighter conditions, making them appropriate for driving light to medium weight piles into normal soils. However, they are not recommended for use with concrete piles, as their high blow rate—ranging from 95 to 300 blows per minute—can lead to damage. The significant force generated can compromise the integrity of concrete structures, making these hammers more suitable for other applications.
Examples & Analogies
Think about using a small hammer versus a large sledgehammer. A small hammer (double acting hammer) can be great for lightweight tasks like fixing a picture frame, but using it to break a concrete wall (heavy load) would be ineffective. Therefore, picking the right tool for the right material is crucial.
Applications of Double Acting Hammers
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
These hammers can efficiently drive steel piles but should not be used on tough soils like hardened clay or concrete where resistance is too high.
Detailed Explanation
Double acting hammers are particularly effective in driving steel piles into soil with typical frictional resistance. However, their usage is limited in tough soil conditions such as hardened clay or when dealing with concrete piles. The resistance offered by these tougher materials would exceed the capacity of the hammer, making it ineffective and potentially damaging during operation.
Examples & Analogies
Consider a car trying to drive on both a smooth road and a muddy patch. On the smooth road, it moves easily (capacity of the hammer), while on the muddy patch, the car struggles to move forward due to increased resistance (unsuitable conditions for the hammer).
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
-
Double Acting Hammer: Uses air or steam to operate a hammer up and down.
-
Blow Rate: Indicates the speed of operation measured in strikes delivered per minute.
-
Cohesive Soil: Provides greater resistance, benefiting the operation of diesel hammers.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
-
A double acting steam hammer can efficiently drive light to medium weight piles into soils with normal friction, unlike heavy-duty hammers.
-
Diesel hammers can be mobilized more efficiently on construction sites due to their self-contained nature, removing the need for separate compressors.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
🎵 Rhymes Time
-
Steam hammer, steam flow, lift it up, watch it go!
📖 Fascinating Stories
-
Imagine a tall steam hammer in a construction site, lifting and dropping with the help of powerful steam, creating energy like a giant's heartbeat on the ground.
🧠 Other Memory Gems
-
Remember 'CIRCLE' for hammer types: C for Concrete, I for Impact, R for Rebound, C for Construction, L for Light weight, E for Energy.
🎯 Super Acronyms
HARD for hammer types
- H: for Heavy
- A: for Air
- R: for Resistance
- D: for Diesel.
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
-
Term: Double Acting Hammer
Definition:
A type of hammer that operates by utilizing air or steam to alternately raise and lower a striking ram.
-
Term: Blow Rate
Definition:
The frequency at which strikes are delivered by the hammer, typically measured in blows per minute.
-
Term: Cohesive Soil
Definition:
Soil that has the ability to stick together, making it denser and often contributing to sticking and higher friction.
-
Term: Compression Ignition
Definition:
A process where fuel ignites from the rising pressure in a combustion chamber.
-
Term: Resonance Method
Definition:
A technique where the frequency of pile driving is matched with the natural frequency of the pile for optimal operation.