Coson 200 kN

Continuous Static Cone Penetrometer

Features:

• Higher CPT production rates
• Ergonomic design
• Easy-to-operate

One step further

A.P. van den Berg has managed to design and build soil testing equipment with a continuous downward movement. The equipment has the same features and technical perfection that is typical of all A.P. van den Berg equipment: reliability, safety and ergonomic construction. It is called: the COSON (COntinu SONdeerapparaat or continuous static cone penetrometer).

The COSON rigs have some important advantages compared to the traditional Hyson CPT units:

• Gain of production time by not having to wait for the cylinders to resume their upper position in order to push down again.
• No loss of data at one metre intervals.
• Elimination of the slip-stick effect at the one metre intervals.
• No dissipation effects interfering with pore water pressure measurements.
• If combined with the Optocone wireless data transmission system (Leaflet S27), the Coson is one step away from realisation of fully automated CPT testing. 

Animation

Technical specifications

The Coson static cone penetrometer consists of two vertical hydraulic cylinders. The piston rods are connected to a lower beam. The lower beam is connected to the subframe. The cylinder tubes are connected to each other by means of an upper beam.

Both piston rods are longer than necessary for their stroke lengths. On these extended piston rods two extra cylinders are mounted. These cylinders ar connected to each other by means of a middle beam, similar to the upper beam. The middle and upper beams work together in a way that the CPT rods are pushed into the soil in one continuous movement.

Pulling is done with intervals. In the lower beam a wiping clamp for CPT rods ø36 mm are mouned, that remove most of the dirt from the rods while pulling.

Specifications

• Type: Coson 200 kN.
• Pushing force: nominal 200, maximum 250 kN.
• Pulling force: nominal 260, maximum 320 kN.
• Force limitation: by means of pressure safety valves.
• Speed while pushing: 2.0 cm/s during continuous process. Maximum speed during "empty" stroke 20 cm/s.
• Speed while pulling: 1.6 or 16 cm/s.
• Speed 0-2.0 cm/s: proportional manual valve for a speed varying between 0-2.0 cm/s.

Differences compared to Hyson

• CPT unit: Hyson 200 kN is replaced a Coson 200 kN.
• Light cover: height of the light cover is extended by 950 mm.
• Depth registration: pulse generator is replaced by a specific depth registration required for the Coson.
• Clamping system: pulling ball clamp ø36 is no longer required.
• Push/pull clamp: no longer required.
• Pneumatic catching clamp: no longer required.
• Air system: since the remaining pneumatic parts do not need air conditioning the air conditioning unit is no longer required.
• Inner casing: the inner casings ø36 en ø56 mm are no longer required.   

The COSON works on a take-over principle. The penetrometer consists of two sets of cylinders. When the upper set has finished its downward stroke, the lower set takes over the movement at the same speed, resulting in a continuous downward movement of the CPT rods. The time saved is about 7 s/m.

A further special feature of the COSON is the hydraulic clamping system which is an integral part of the testing cycle. Both hydraulic cylinder sets are fitted with a hydraulic clamp. The upper clamp automatically clamps the CPT rod when installed during downward movement. Upon completion of the stroke of the upper hydraulic cylinders, the upper clamp automatically releases the rod and the clamping function is taken over by the lower hydraulic clamp. The CPT operator only needs to add on new CPT rods. The hydraulic clamps have a variable CPT rod diameter capacity.

Pulling is still done discontinuously. During pulling, the CPT rods have to be taken off and put back in storage. At the high pulling speed, a continuous movement would not leave enough time to do this.

The COSON is suitable for installation on any CPT vehicle.

Leaflet S36