- How was the idea of using a screw to transport swarf born?
The screw is a patented technology, the result of many years of research begun to overcome the limitations of traditional transportation systems already in place. This research resulted in a universal technology perfectly in line with the current needs of machine tools which, by performing various types of processing, generate a wide range of swarf morphology.
- Govoni screw or traditional auger?
Ancient Egyptians used what Galileo called "the most wonderful invention of Archimedes" to bring water from the Nile to the fields and reclaim the marshland. The screw uses the same principle invented by Archimedes to transport materials horizontally and vertically, but they are two completely different technologies.
Currently the traditional screw is used mainly for transporting sludge, powdery or granulated material and small chips. The Govoni screw transports swarf of every size, even in tangles and has operational and structural characteristics and resistance to wear and tear that is very different from the traditional auger.
- Is it really true that the screw is universal and can transport any swarf morphology and any type of metal?
Due to the special geometry of the manifolds, defined from time to time according to the technical specifications of the project, the screw is truly universal and transports any swarf morphology (powdery, short, medium, long, flowing, tangled bundles) and any type of metal.
- For the creation of a centralised screw system, are there limitations to the flow of the chip, layout, angles, length of the manifolds etc.?
Depending on the diameter of screw used (diam. 95, diam. 130, diam. 150, diam. 200), the container body can have different sizes and the maximum capacity for swarf increases with the diameter. The flow rate of each screw manifold can easily be increased by accelerating rotation of the screw itself.
The network of manifolds in the system is adaptable to all layout requirements and can be extended with successive enlargements. The screw technology also allows the vertical transportation of swarf and the creation of aerial manifolds. For the underground lines, the pits are simplified and the set of manifolds is non-invasive and quite elegant.
The manifolds can be grafted on to one another at the same level as if it were Meccano, avoiding deeper levels for discharge from one conveyor to another, making it possible to operate manifolds, even very long ones, with a single motor. At the moment we made a screw manifold with a diam. of 200 and a length of 70 metres driven by a single motor and it is likely that in the future we will exceed this limit.
- If I change the layout of the machines or even the factory, can I somehow recover the system already installed?
With the traditional conveyor you are obliged to build the facility in the pit, so digging burrows in the workshop means restricting the machine layout and the entire layout in the future. With the screw instead there is the possibility of choosing the overhead solution that is very versatile and flexible, allowing you to easily follow changes in the layout.
Even if you move to a new facility, the aerial plant can be easily readjusted to the new layout and so with appropriate modifications, it is often possible to recover the entire system.
We have many clients who found themselves in this situation and for them we were able to readjust the already active system in the new site at a very low cost.
- What is the Product Life Cycle Cost of a screw system?
The Product Life Cycle Cost is equal to the initial investment plus the electrical power needed to operate it, since there are no additional costs over time related to obsolescence of the product, neither in terms of spare parts (not required for absence of wear and tear) nor in terms of maintenance (hours of downtime, dedicated labour etc.).
All this is definitely less convenient for Govoni but the satisfaction of our customers is already a great reward.
- Usually for any mechanical system, ordinary and extraordinary maintenance are planned, in addition to lists of spare parts to keep in stock for replacement. Is it really true that Govoni screw does not require any maintenance or spare parts?
The screw is very simple technology, consisting of a tube, a helix and the manifold where it is housed without support; this simplicity and the special heat treatment undergone by the screw and all of the components in contact with it, allow for the reduction of ordinary maintenance to mere filling/change of the gear oil and tightening of the manifold bolts. If the system is well managed, the only spare parts needed over the years are the gear motors.
- How can Govoni screw transport the swarf vertically?
The upstream principle is still based on the rotation of the screw that operates in its entire length in the tubular manifold, however, the critical point of this transport is in the junction between the vertical and horizontal manifold, where it is necessary to design the right configuration in each case, based on the know-how and the multi-year experience of our technicians.
- There are screw systems that work without interruption for many years. What is the secret of the longevity of the screw?
As for the lack of maintenance and spare parts, there are no secrets: also in this case the reason is linked to simplicity and resistance to wear and tear ensured by the heat treatment. Just visit our older systems running 24 hours a day, to notice how they have remained intact.
- The screw is a patented technology of which Govoni is the undisputed leader: being a simple technology, is it also easily imitable?
Those who have tried to imitate it made mistakes because there are some critical aspects related to the internal equipment of the conveyor that need so many years of experience that no imitator could replicate without the high cost of study, analysis and testing. The science of the chip is an 'empirical science' and so for each new project, we use our extensive business experience, drawing on solutions adopted for systems already installed that have been carefully documented.
- I want to implement a centralised system for the transport of swarf, but I am undecided between Govoni screw and another technology, why should I prefer the screw which can maybe cost more?
That of the swarf is not an exact science, choosing the right technology depends on many factors involved in each project. In some cases there may be conditions that make this choice indifferent. However, some of our customers already have systems with other technologies, they then equipped other lines with our screws citing a number of reasons to us. Here is an example:
- Transport of wet swarf is usually difficult because it sticks to the sides due to the viscosity of the liquid, forming layers difficult to remove; the screw provides high performance even with wet swarf that can drip into the vertical sections where present;
- With other technologies it is necessary to grind the swarf to a very fine consistency, especially if originally medium or long or bundled; this means entrusting efficient operation of the whole system to a shredder that requires constant maintenance to work well; with our screw instead, the chip is crushed and compacted due to the rotational movement of the screw itself, therefore often the use of this accessory can be avoided;
- The maintenance of a system with other technologies is very demanding and therefore expensive, the plates and all parts subject to mechanical stress are also exposed to heavy wear and tear, especially with corrosive materials; our screw manifolds instead require no maintenance and are not subject to wear and tear due to the hardness achieved with heat treatment;
- With alternative systems, operational blocks are possible due to localised clusters of swarf that fail to complete their trip, especially if there are curved sections: the screw rotates inside the straight manifolds that prevent agglomerations and operational blocks;
- The simple rotation of the screw determines efficient mechanical transport of the chip and requires, under the same operating conditions, considerably inferior energy absorption compared to other technologies.