3.2. Concrete Piles

So, basically what to do here is, so this is a setup of the double acting steam hammer, you can see two cylinders one is the upper cylinder, other one is a lowest cylinder. Now in the upward stroke what you do is, you supply air into the lower cylinder. So, when you supply into this, this is a lowest cylinder, when you supply air into the lower cylinder, the hammer which was earlier in the lower cylinder will be pushed up into the upper cylinder.

The double acting steam hammer has two cylinders: one upper and one lower. To operate, air is supplied into the lower cylinder. This action pushes the hammer upward into the upper cylinder. The mechanism relies on the pressure of the air to push the hammer, indicating how compressed air power is applied in this process.

Think of it like a syringe. When you push down the plunger, it forces liquid upward. Similarly, when air pushes down in the lower cylinder of the steam hammer, it forces the hammer up.

So, the hammer is pushed up into the upper cylinder, the air which was already there in the upper cylinder will expel out to the exhaust. So, basically what you are doing here is you supply air into the lower cylinder. So, that will push your hammer upward into the upper cylinder and the air which is already in the upper cylinder will be released through the exhaust, now your upward stroke is complete.

Once the hammer is pushed to the upper cylinder, the air that was previously in the upper cylinder is expelled through an exhaust port. This cycle continues as air is alternately supplied to the upper and lower cylinders to create upward and downward motions of the hammer, which allows for a continuous operation.

Imagine a balloon. When air fills it, it expands, but when you let the air out, it contracts. In the hammer, filling air pushes the hammer up, like inflating the balloon, and releasing air lets it fall back down.

Another important thing we need to know with respect to double acting hammer is in this most of the blow energy is the derived from the steam energy. Both for the upward stroke as well as for the downward stroke, the blow energy is derived mainly from the steam energy. So, 90% of the blow energy is derived from the action of air or the steam.

The double acting hammer relies heavily on steam energy, accounting for about 90% of the energy used to drive the hammer for both upward and downward strokes, reducing the need for heavy hammers. This energy system allows for shorter strokes and more efficient operations.

Think of a kettle. When it boils, the energy from the steam can be powerful enough to push the lid off slightly. Similarly, steam drives the hammer with substantial energy, making it lightweight.

So, that is why, for the double acting hammer we need not for a heavier hammer. We can go for lighter hammers, smaller in size and you can go for the shorter stroke or shorter height of fall. So, these hammers are basically designed to be lighter in weight.

Due to the reliance on steam energy, the design of the double acting hammer favors lightweight materials. Heavy hammers are unnecessary, allowing engineers to create smaller, more efficient hammers that can deliver effective blows without the fatigue of managing a heavy tool.

Consider a small rubber mallet versus a sledgehammer. The mallet can be just as effective in driving small objects while being much easier to handle. This is similar to the design of the double acting hammer.

And this hammer is basically designed for lighter conditions, lighter conditions in the sense. So, it is basically designed for light to medium weight piles and for soil with normal frictional resistance.

Double acting hammers are designed specifically for 'lighter conditions.' This means they are most effective when driving light to medium weight piles in soils with normal friction. They are not recommended for heavy-duty applications like penetrating very hard or dense clay.

It's like using a lightweight shovel for gardening versus a heavy-duty excavation tool for construction. Each has its purpose based on the task's requirements.

So, you should never use this double acting hammer for concrete pile. Because these double acting hammers, they basically have a very high blow rate, if you look into the blow rate, you can see that the blow rate will be 95 to 300 blows per minute. So, it is very high when compared to the single acting hammer.

Double acting hammers operate at a blow rate of 95 to 300 blows per minute, a rate that is too high for concrete piles. The impact of such rapid blows can easily damage the concrete structure, therefore they should be avoided in this application.

Imagine hitting a piece of glass with a hammer repeatedly. If you strike too quickly, it may shatter. The same principle applies to concrete piles; excessive blow frequency can cause them to break.

So, let me summarize what we discussed, so your use of steam energy in driving the ram allows use of shorter stroke and compact hammer than single acting hammer. So, when compared to single acting hammer these hammers are more compact smaller in size, lighter in weight and they have a shorter stroke.

In summary, the double acting hammer is more compact and efficient than the single acting hammer. The steam energy allows for shorter strokes, ultimately making it a preferable choice for specific applications in driving lighter piles into soils with normal resistance.

This is akin to using a compact power tool for home repairs rather than a bulky machine. The compact tool achieves the desired results with ease and efficiency.

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