GeoMil Equipment B.V. specializes in the manufacturing of Cone Penetration Test equipment. The cones themselves are of mechanical or electrical type:
 

All cones are temperature compensated and provided with a built-in amplifier.

The output from the cones is a voltage signal, amplified in the cones and A/D converter in the acquisition unit GME-500, see data sheet. All cable connections are made with so called Lemo contacts.

The conversion can also be provided downhole, allowing for a cable or cordless data transmission.

Subtraction Cones
The 10 cm2 and 15 cm2 subtraction cones (S) come with the following channels: Cone resistance (C), local friction (F), inclination (I) and pore pressure (P), making the following abbreviations: S10CF or S10CFI or S15CFIP. The available measurement ranges are listed below but other ranges can be provided upon request. Pore pressure is measured behind the shoulder of the tip (u2 position) or on the tip itself (u1 position) (S15CFIP cone only). Figure right: Sketches of 10 and 15 cm2 subtraction cones with overlain, a 10 cm2 cone, assembled and with the measuring bodies displayed: the lower body for the point resistance, the upper body for both point resistance and local friction.
Most 15 cm2 cones of the subtraction type recently in use are not in accordance with the geometric requirements! Since most national standards refer only to 10 cm2 cones but do not specify the 15 cm2 types, the early designs for the 15 cm2 cones had a friction sleeve surface area of 200 cm2 but not of 225 cm2 and the cylindrical area behind the friction sleeve was too short in lenght. As a result the tapered end piece, allowing for the transition from 44 mm to 36 mm in diameter, was kept rather short with the positive effect of a robust cone construction. However, the result on the friction measurements was often not sufficient and the tapered transition piece can cause substantial soil disturbances influencing the measuring results in a negative way.
For this reason GeoMil - as the so far only manufacturer of 15 cm2 subtraction cones - re-designed the cone in such a way that the friction sleeve now provides 225 cm2 and a cylindrical end piece ensures for the necessary length until the tapered cross-over starts, allowing for the transition to standard 36 mm sounding tubes. All existing subtraction cones can be modified with minor efforts and at moderate costs. Please contact us for further details.