4.2. Operating Mechanism

So, in the upward stroke what you do is, you supply air into the lower 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 air which was already there in the upper cylinder will expel out to the exhaust.

In the upward stroke of the double acting steam hammer, air is directed into the lower cylinder. This influx of air creates pressure that forces the hammer upwards into the upper cylinder. During this movement, the compressed air that was previously in the upper cylinder is released through an exhaust. This action completes the upward stroke, allowing the hammer to elevate.

Think of it like a syringe; when you push down on the plunger (supply air), it forces the liquid (hammer) up into the top chamber (upper cylinder), while the air already in that chamber is forced out.

In the downward stroke, you supply air through the inlet into the upper cylinder. When you supply air into the upper cylinder, the hammer which was already there will be pushed into the lower cylinder. The air which was already in the lower cylinder will be expelled out through the exhaust.

During the downward stroke, the process is reversed. Air is supplied into the upper cylinder, creating pressure that drives the hammer back down into the lower cylinder. As the hammer descends, the air that was in the lower cylinder escapes through the exhaust. This alternation between upward and downward strokes enables the hammer to function continuously.

Imagine a pump: when you pull the handle up (upward stroke), you create a vacuum that pulls liquid in. Then, when you push down (downward stroke), the liquid is pushed out. Similarly, the hammer moves up and down, forcing air out and creating pressure.

Most of the blow energy is derived from the steam energy. About 90% of the blow energy is derived from the action of air or the steam. This means lighter hammers can be used.

In the operation of the double acting hammer, a significant portion, approximately 90%, of the energy required for lifting and driving is sourced from steam. This allows for the design of the hammer to be lightweight compared to other types, as it does not rely solely on the weight of the hammer for effectiveness. Consequently, smaller and lighter hammers can perform the same tasks as heavier ones.

Using a bicycle is an analogy here. Just as a lighter bicycle frame allows you to pedal faster with less effort due to the efficient use of gears, a lighter hammer uses steam power efficiently to drive piles without needing extra weight.

These hammers are designed for lighter conditions, suitable for light to medium weight piles and normal soil with normal frictional resistance. They should not be used for very tight clay or concrete piles because of their high blow rate.

The design of double acting hammers is intended for applications where the soil conditions are not extremely tough. They work best with light to medium weight piles in soil with standard frictional resistance. The high blow rate of 95 to 300 blows per minute could potentially damage concrete piles, which are more fragile than their steel counterparts.

Think of using a delicate touch when hanging fragile decorations; using a sledgehammer would be excessive and likely cause damage. In construction, using a less intense tool like a double acting hammer for suitable conditions enhances effectiveness without causing harm.

The use of steam energy in driving the ram allows for a shorter stroke and a more compact hammer than single acting hammers which are designed for heavier conditions.

In summary, double acting steam hammers leverage steam energy, which facilitates the design of more compact and efficient machinery, enabling shorter strokes and lighter weights. This makes them particularly advantageous in situations where high-speed pile driving is necessary without the cumbersome weight of traditional hammers.

Consider using a small, efficient electric drill instead of a bulky manual tool. The electric drill operates faster, is easier to handle, and achieves results that would be cumbersome with a heavier tool - similar to how double acting hammers streamline the pile driving process.

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