Rotary seals for drilling machines

In the drilling and earth-moving machinery industry, maintenance during work operations is very hard. Machines dig several hundred meters underground and in some cases it is not possibile to even stop the work in progress. The break would also slow down the work, always subject to severe deadlines. Therefore the choice of the type of technology and the durability of the seals are particularly important factors.

Challenge

One of our customers operating in the drilling sector asked us to design a rotating seal for mud able to respect the design characteristics and capable of withstanding an internal external pressure differential of 0.5 ÷ 12 bar and whose design would be supported by a study, and relative technical report, providing the both durability and resistance data (all pre-existing solutions had failed).

Solution

ATP’s technical team firstly analyzed the operating conditions of the application

• Medium: sludge / water (ext.) – Grease (int.) • Movement: Rotation • Sealing diameter: 270 mm • Speed: 35 rpm (0.8 m / s on the sliding area) • Pressure: int. 0.5 bar (min.) Ext. 12 bar • Temperature: -10 ° c ÷ + 50 ° c

The study of the application led our designer to define a rotating front seal with particular profile carachterized by high resistance to usage in SINTEK H-TPU.

Therefore a FEM analysis was carried out to see the different behavior of the seal subjected to internal and external pressure loads. Our staff also carried out a study and optimization phase, again through FEM technology, to determine the specific sizing of the profile. This study led us to modify the profile, adding an additional lip on the radial part that allows greater stability to the seal itself.

Testimony

This particular tailor-made seal was created after several studies shared with the customer, who is very satisfied by ATP technical team’s approach and expertise.