How does a mole work?
Pressing machines MAX Breakthrough Power belong to the group of pneumatic-impact machines. Due to their purpose, they are divided into two main groups: moles and hammers. The principle of operation of pneumatic-impact devices can be presented in the simplest way as follows: the construction of the machine type: mole, hammer, is a body made of high-impact steel with a head, inside the machine there is a ram with maximum mass, which, driven by compressed air, moves in a reciprocating motion, hits the head and transfers kinetic energy to the entire device, driving the mole. The principle of operation of pressing machines can be observed in the two animations below.
Compressed air is supplied to the mole through a supply hose. This air pushes the piston located inside the cylinder (housing) of the mole. The piston hits the element of the mole's head called the chisel with force, and at the same time the air flowing into the machine starts to push the piston towards the back of the mole, to prepare its position for another impact on the front part - the head.
The work of the mole backwards is analogous. The only difference is the change in the position of the controller elements in the mole, via the pneumatic valve responsible for changing the direction of work. When the position of the controller element is changed, the air flowing into the mole also pushes the piston, but the piston does not hit at the point of contact with the chisel, but in the rear part, where the controller sleeve is located.
Depending on the size of the machine, the piston hits the head 4-6 times per second. It is therefore easy to calculate how many such cycles (impacts) occur during the entire period of use of the machine. It is enough to assume that one impact causes the mole to move linearly (along the path of the pressed mole) by 0,5 centimetres (in practice it depends on the type of soil), and we will get the result of 4000 impacts needed to perform a 20-metre long press. Among our Clients are companies performing up to 100 metres of pressing per day, which gives 20 km of pressed mole per year, i.e. we have 4.000.000 piston strokes. And our machines work for Clients for up to 8 years.
It is worth mentioning that such long runs are possible thanks to the use of Teflon guides and seals. These elements are subject to wear and their replacement is associated with a small cost and makes the pressing machine work like new for another long period of time after their replacement, without air leaks and thus without loss of efficiency. On the other hand, moles manufactured in technology without replaceable sliding and sealing elements, according to the manufacturer himself *, after 5 km of run require thorough regeneration. Regeneration usually consists of replacing worn steel elements: piston and/or cylinder. This is a very expensive procedure, as these are the two most important and expensive elements of the ramming machine. Moreover, in machines without Teflon seals, with increasing period of use of the machine, we deal with gradual loss of impact energy, due to increasing clearances between cooperating elements, i.e. ram and body. These clearances cause leaks of supply air flowing into the mole. Sometimes, the loss of energy is hardly noticeable if the mole is powered by a compressor with a much higher capacity than the original capacity for a machine of a given caliber. In such a case, leaks and air leaks resulting from the wear of the elements are compensated by an increase in the amount of air supplied to the mole. However, this happens at the cost of increasing the engine speed of the working compressor and significantly affects the increase in the fuel consumption of the compressor. Working with such a mole significantly increases the cost of carrying out ramming works.
WINDING MAX these are machines that move independently in the ground based on the principle of displacement and compaction of the excavated material, they are equipped with a controller with remote, pneumatic override; the change of the "forward-backward" working direction can be made during pressing through the control valve on the oiler, without the need to stop the mole.
HAMMERS MAX are used to drive in steel pipes and other elements after appropriate adjustment of the equipment. The standard set includes pipe driving attachments. Some larger moles can also be used to drive in pipes, so they are very universal machines. A source of compressed air is necessary to work with pneumatic-impact machines. It is recommended to use screw compressors. The maximum working pressure is 7 atm.
