When concreting there is a risk of the concrete segregating in the downpipe. To ensure a safe concreting process, LEFFER has developed a special HD concreting tremie pipe system: The tremie pipe joints we have designed can resist very high tensile forces, which prevents the concreting pipe string from tearing off, even in case of very long pipe strings. The high-precision, machine-manufactured parts have a high degree of tightness and are therefore also ideally suited for applications in the field of air-lifting technology. 

The reduction of individual parts (in contrast to flanged pipes) reduces wear at the joints. Easy to handle, maintain and (dis)assemble, LEFFER tremie pipes NW 150, 200, 250 and 300 save valuable time and thus costs at the construction site. 

Decades of practical experience are incorporated in the design and continuous further development of our cutting crowns. For continuous drilling, the tooth system, i.e. tooth shape and number, contact pressure and the corresponding free cut must be correctly selected. The geology of the ground determines the design of the cutting teeth. Taking these variables into account, LEFFER offers individual cutting crown types for a wide range of requirements. 

For cased boreholes greater depths or diameters greater than 1500 mm, LEFFER HD has casings in its portfolio that meet the high requirements for particularly large drilling depths. Reinforced casings joints with backlash-free, conical bolts and larger wall thicknesses reduce wear on the casings joints and also ensure reliable transmission of vertical forces and torque. 

For cased boreholes, LEFFER offers double-walled casings in different of useful lengths. Our low manufacturing tolerance for diameter, roundness and straightness pays off on the construction site: Precisely fitting casing joints ensure fast, straight placement, bolting and optimum force transmission. The casing joints, consisting of a female and male part, are secured with radially arranged conical bolts. The inside and outside of the casings are smooth throughout their entire length, which prevents the reinforcement cage or drilling tool from getting stuck when pulling the casing.

LEFFER casings have also proven themselves many times over in cased kelly drilling through water-bearing soil layers or in drilling with water ballast. To prevent water and fines from entering the casing, both the cone bolts and the casing joints can be sealed with additional sealing rings.