Corrugated walls technical details:

The spot welding is a reinforcement that can be applied along the embossment lines, it is useful in order to make the corrugated wall stronger, giving it a better resistance to the dilatation due to the oil heat and pressure inside the tank.
Our automatic production lines can be set following the customer drawing and requirement, the spot welding operation will be carried just after the embossment phase.
The spot welding can be applied according to the scheme reported below.

The charts above represents the maximum number of spot welding points, depending on the coil dimension (H) and their exact position inside the embossing. The distance of two welded point varies from 80 to 100mm. We can also reduce the number of spot welding points per your request and choose any type of spot welding point distribution.

The spot welding can be done on one embossing, on two embossing (per your request might be the internal and the external, or the internal and the one in the middle…or any other possible combination) or on all three embossing performed.

Super onda profile:

Our press machine has the capability to make a new profile of the corrugated wall which facilitate the oil circulation inside the walls. In fact this new profile which we call “SUPER ONDA” has the upper and the bottom part of the corrugated fins with a larger profile (internal gap is about 12mm instead of 6mm).

This profile creates a bigger section where the oil circulates and it increase the quantity of hot oil which pass through the wall per minute.

This higher performance allows to optimize the corrugated walls profile because there is some temperature and dissipation advantages compared to the “normal profile” which can helps the engineering departments to save on the transformers raw materials and costs.

Our equipment can spot weld on the bottom of the corrugated walls a metal strip 15mm x 1.18mm
This metal strip improves:

• the welding of the corrugated walls, it means no imperfection on the bottom of the wall with a perfectly straight profile
• the productivity of the welding shop because in the area where the welder join the corrugated wall with the tank, the thickness is not 1.2mm but it becomes 2.4 mm, 1.2mm for the corrugated wall sheet and 1.2mm for the metal strip
• the robustness of the wall, in fact the corrugated wall is reinforced in the weakest point (where the thin has the 90 degrees angle) with the strip, improving the mechanical endurance under vibration and mechanical shock tests

Embossing:

The embossing has been designed to make the corrugated walls more robust, especially in the big tanks where the pressure of the oil is huge and where the depth of the fins (P) is high. There are some standard measures of depth of the fins which allows to have one, two or three embossing (see charts below). It is possible also to decide to have one or two of the possible embossing creating a combination: for instance in a 400mm depth fin it is possible to have only the internal embossing at 60mm and not the other two at 160mm and 260mm.

The embossing can be spot welded or not. If it is planned to spot weld the embossing the result is that the quantity of oil needed into the transformer is less but the tank bacame more rigid. That is why, in particular in the hermetic tanks, it is needed to pay attention to maintain always some flexibility on the walls, allowing the tank to “breath”. If the embossing in the hermetic tanks are spot welded there might have some problems of rupture of the coil by fatigue in the points where the spot welding are placed.

There is two possible schemes of embossing: the first one concern tanks with conservator (non hermetic tanks) that permit to place on the fins more embossing at different heights. More embossing means more resistance of the fins at the oil pressure due to the push from the conservator. The second scheme is for hermetic tanks, the possible embossings to place are less and only from a depth of the fins quite high because the pressure to counteract is lower without conservator.

Remembering that it is possible to combine the different positions as well as not applying any deep drawing, the following scheme for non-hermetic tanks (with conservator) is as follows:

• depth of the fin (P) from 40mm to 170mm no embossing
• depth of the fin (P) from 180mm to 270mm one embossing
• depth of the fin (P) from 280mm to 370mm two embossings
• depth of the fin (P) from 380mm to 400mm three embossings

As can be appreciated from the scheme the application of the embossing are fewer and only in some cases they can be combined. The scheme to be followed for hermetic tanks is as follows:

• depth of the fin (P) from 40mm to 270mm no embossing
• depth of the fin (P) from 280mm to 370mm one embossing
• depth of the fin (P) from 380mm to 400mm two embossings

We are capable to load any type of container and we can provide you the packing list and the layout of the container in order to optimize your shipping cost.
The packaging for international shipping is carried out with particular attention to protect the product against rust (with antirust oil and nylon) and against damages (anchoring the pallets to the container very accurately).
We usually load one fin wall inside the other one, as in the figure below, to optimize the space available either on the truck or on the container.
Pallets are made directly in Convett, customizing it following fin walls dimensions, with fumigated wood if the country laws where the customer is located asks for it.

Pallets optimization

Customized loading

Safety, for first