6.1. Quiet Method of Pile Driving

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.

In a double acting steam hammer, there are two cylinders (upper and lower). When air is supplied to the lower cylinder, it pushes the hammer upwards into the upper cylinder. This arrangement allows for continuous motion as air is alternately supplied to each cylinder.

You can think of the double acting steam hammer like a see-saw. When one side goes up, the other side goes down. In this case, the supply of air is like someone pushing down on one side, making it go up while the other side rises.

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 moves to the upper cylinder, the air that was previously contained there is pushed out through the exhaust. This expulsion is critical for creating space for the hammer in the upper cylinder and allows for the next stroke of the cycle.

Imagine screwing a cap onto a bottle. As the cap is tightened, air inside has to escape; otherwise, the bottle can't be capped securely. Similarly, as the hammer moves up, air must escape to allow the next stroke to occur.

So, what are you doing the downward cylinder? You supply air through the inlet into the upper cylinder. So, when you are supply air into the upper cylinder, the hammer which was already there will be pushed into the lower cylinder. And air which was already in the lower cylinder will be expelled out through the exhaust.

To complete the hammer's motion, air is supplied into the upper cylinder, which forces the hammer back down into the lower cylinder. The air that was in the lower cylinder is expelled through an exhaust. This cycle of upward and downward strokes continues, allowing for effective pile driving.

It's like a balloon; when you squeeze one end to let air out, the other end expands. In the same way, as air is pushed into one cylinder, it promotes the hammer's downward motion while displacing air from the opposite cylinder.

So, 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.

The double acting hammer uses steam energy for its operation. About 90% of the energy needed for striking comes from steam energy, reducing the need for heavier hammers. Lighter and more compact hammers can be used effectively for pile driving.

Consider how a small toy car can move quickly with the help of a balloon. The balloon stores energy, which when released, drives the car fast. Similarly, the steam energy allows the hammer to do its work efficiently without needing excessive weight.

So, it 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.

This hammer is suitable for light to medium weight piles and is not designed for tough conditions like high frictional resistance clay. Using it in unsuitable conditions, such as driving concrete piles, risks damaging the pile due to its high blow rate.

Think of wearing specific shoes for different activities. For running, you'd wear light sneakers, while hiking would require sturdier boots. Similarly, the double acting hammer is tailored for certain conditions, and using it beyond those limits can lead to problems.

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.

The blow rate of double acting hammers is significantly high (95 to 300 blows per minute), which is effective for the right materials but could lead to damage when used on more fragile materials like concrete piles.

Imagine trying to tap a delicate cake. If you pat it lightly, it stays intact; but tapping too hard can ruin its structure. In the same way, the high blow rate must be managed carefully according to the material being driven.

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, using steam energy with the double acting hammer creates a compact, lightweight system that delivers effective pile driving with a shorter stroke compared to the single acting hammer. This design simplifies operation and makes it more efficient for compatible materials.

Think of a modern, lightweight laptop versus an older, bulkier desktop computer. The laptop is compact and performs well, making it easier to use and carry around, allowing for effective work without the size burden.

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