Nortrade

General
IHC Hydrohammers are accelerated, hydraulic impact hammers with high energy transfer. At full energy setting on the control panel the ram gets an acceleration of 2G. The energy for each blow is shown in a display. Different from most other piling hammers the IHC Hydrohammers are characterized by energy transferred into the pile and not by the ram mass and chosen fall height. As a natural consequence the maximum energy transfer in kNm (kJ) is used as a figure in the model designation. IHC manufacturers hammers from 30 kNm to 2300 kNm. Nor-Trade represents CAPE Holland. Through this company IHC Hydrohammers up to S-200 can be supplied.

Also the letters S or SC are part of the model designation. S stands for steel and C for concrete. The S-type hammers are used for installing steel piles (also sheet piles) and the SC-types for installing both steel piles and concrete piles. The SC-types are more versatile but the S-type more efficient on steel piles.

The IHC Hydrohammers are suitable for piling above water and under water.

The ram weight on IHC Hydrohammers is accelerated by compressed Nitrogen in the cap (top of the hammer). By increasing the Nitrogen pressure by the installation of raked piles, the loss of energy otherwise experienced due to the reduced, vertical gravity component on the ram weight, can be fully compensated for.

IHC Hydrohammer with ballast weight installing monopile at the sea

The compact enclosed design simplifies handling whilst protecting vital components and thereby lead to low maintenance costs. The ram weight is fully encased in the hammer housing and the top of the ram constitutes a piston that works in a cylinder with compressed Nitrogen. Thus, at full energy setting on the control panel the ram gets an acceleration of 2G - twice the gravitation.

The IHC Hydrohammers are known for their high efficiency, extremely low maintenance costs and long lifetime.

Various IHC Hydrohammers onshore and offshore, on steel and concrete piles, leader guided and free-hanging.

Main advantages by the IHC Hydrohammer:

• Can deliver single blows.
• High blow rate (from about 50 to 150 blows/min depending of transferred energy).
• Energy per blow fully adjustable from 5 % of nominal energy to 100%.
• Full energy can be delivered during piling in raked positions by adjusting the Nitrogen pressure in the hammer cap (head).
• High energy transfer as no cushing material is used for piling steel piles.
• High energy transfer due to ram weight design.
• Piling of steel piles can take place with the hammer freely suspended due to the design of the standard type sleeve.
• Can operate under water without loss of energy. Up to now IHC Hydrohammers have operated down to 900 m water depth.
• The Hydrohammer is fully encased and has exceptional reliability and low maintenance costs.
• By the mounting of a special developed bellow around the pile, the noise can be reduced down to less than 80 dB(A).

Two series of hammers: S-series and SC-series
The IHC Hydrohammers are available in two series, the S- and the SC-series. The S-type is for steel pile installations and the SC-type for both steel and concrete pile installations - hence the model designations. The speed of the ram on the S-series is too high for concrete piles which will be crushed unless the speed is reduced. Therefore, the ram speed on SC-hammers is kept lower and the mass of the ram subsequently increased to provide the same energy on S- and SC-hammers with the same size (same figure in the model designation).

All in all - with the same stroke as the S-series hammers, the SC-series have a lower impact velocity making them a better choice for concrete piles.

Construction and operating principle

Cross-sectional view of SC-hammer

The IHC Hydrohammer set
Basically an IHC Hydrohammer set consists of:

• Hammer.
• Pile sleeve of special steel or Polypenco, or - for installing sheet piles - sheet pile legs with steel anvil.
• Power pack.
• Control unit with pendent.
• A set of hoses.
• Printer for printing out piling reports during operation (optional).

Hammer
The IHC Hydrohammer combines a solid one-piece ram with a fully enclosed hammer housing. The ram is guided by upper and lower oil lubricated bearings. The top of the ram is a piston working in a cylinder with compressed nitrogen.

The operation cycle starts with the lifting phase of the ram. Valve P (see the image above left) in the pressure line is open and valve R in the return line closed. When the pre-set stroke is reached valve P closes and R opens, thus allowing the ram to start its downward stroke. The ram is accelerated by the pressurized nitrogen above the main piston, giving the ram an acceleration of up to 2G, depending on the chosen energy setting on the control unit or pendent. The acceleration reduces the necessary stroke and increases the blow rate of the hammer.

After impact the cycle repeats.

The IHC Hydrohammer is at present the only hammer being a true accelerated hammer. Other known hammers may have a design that compensates for the energy loss during the hydraulic cycle.

S-30 with sleeve (red)

Pile sleeve and sheet legs
The pile sleeve (the red part on the sketch to the left) or sheet legs (the black part on the sketch beneth) is/are mounted under the hammer. During piling the hammer with sleeve is placed over the pile. The sleeve incorporates an anvil plate (no. 13 in the sketch above) of steel which is in direct contact with the pile when steel piles are installed (pipes, profiles or sheet piles) - no cushing material is used - or Polypenco when pre-cast concrete piles are installed. The anvil is hit by the ram - likewise without cushing material - whereby the energy is transferred into the pile.

With a standard pile sleeve the hammer can operate freely suspended on steel piles.

Power pack
The power packs are designed for driving the IHC hammers. By minor modifications they can drive other hydraulic equipment as well - for instance APE vibratory hammers.

Control unit with pendant
The control panel and its pendant controls and monitors the functioning of the hammer and its hydraulics. Important data as blow energy, blow rate, operating pressure, engine rpm and error detecting are displayed directly on the control panel. The control function comprises an automatic shut-off in case of errors in the piling process.

Printer
By installing a printer, piling reports can be printed out. These reports can contain project data, pile data, date and time, starting and stopping times, blow rate per 25 cm, average blow energy per 25 cm, number of blows per minute, total number of blows delivered, total energy delivered and error messages.

S-hammer with legs for sheets (black)

Noise Reduction
The IHC Hydrohammercan be provided with a noise reduction package. This consists of a shroud around the hammer housing and a bellow around the anvil/helmet and pile.

The accessory has been developed in co-operation with the Dutch Research Institute TNO/TPD. Noise levels can be reduced down to less than 80 dB(A) at 7 meters.

Specification - IHC Hydrohammer, S-type

Specification - IHC Hydrohammer, SC-type

Specification - IHC Hydrohammer, Power Packs