Van Groningen and Hoondert invest in NPK's GH series

Van Groningen Sloopwerken B.V. is demolishing a bunker complex in Rockanje. Two new and heavy NPK demolition hammers, supplied by DemTech, are being used.

Van Groningen Demolition Works of Middelharnis was awarded the contract to demolish the complex. That consists of five heavily reinforced concrete bunkers, including a command and ammunition bunker. In total, an estimated 2,000 cubic meters of heavily reinforced concrete must be demolished with a demolition hammer. This requires large and robust equipment. For this, Van Groningen is using its own Kobelco SK350-10 and SK500-10. These machines are equipped with an NPK GH-15 and GH-23 hammer. Recently they invested in the GH-23, which is deployed on the large 50-ton Kobelco SK400DLC-10E and SK500-10 demolition cranes.

Director John van Groningen has chosen demolition machines and tools from Japan for many years, and for good reason. In doing so, the fleet of demolition equipment consists mainly of Kobelco excavators and NPK hydraulic demolition hammers. Along with the new hammer, DemTech also delivered an NPK SV-42XCR concrete cutter. With this, Van Groningen is able to make short work of the heavily reinforced bunker complex. They are also calling in the help of Hoondert, which is deploying a Komatsu PC600LC-8 demolition crane with a brand new and heavy NPK GH-30 demolition hammer.

Quality and reliability

For Van Groningen, the choice for a new demolition hammer was quickly made. For years they have been demolishing with NPK hammers and these have proven themselves for their excellent quality and reliability. They have a H-08X, GH-10, GH-15 and the new GH-23 demolition hammers. The GH-23 weighs around 4,525 kg and is suitable for excavators in the 50- to 60-ton weight class. It delivers between 300-400 blows per minute and requires an oil flow between 250-320 l/min. The minimum working pressure is 210 bar. The demolition hammer delivers 18,300 Joules of impact energy at 400 blows per minute.

Coincidentally or not, Hoondert from 's Heerenhoek is helping with the demolition of the World War II bunker complex with a 60-ton Komatsu excavator. This is the first time the new GH-30 is being used. Hoondert has also been using NPK demolition hammers for many years, including a PH-1, E203, E208 and two E210s. Because of the increasing number of demolition projects requiring the use of a hammer, a new GH-30 demolition hammer was purchased. This has a weight of 5,450 kg and is suitable for excavators in the weight class between 50 and 80 tons. This demolition hammer delivers a maximum of 20,350 Joule of impact energy at 390 blows per minute. NPK thus claims to have the highest percussion power.

The advantage of the NPK demolition hammers is that they have a nitrogen chamber and directly driven piston. As a result, no return pressure is created and the chisel strikes even with a double-acting function. If a ball valve or quick disconnect would close or break, internal damage is prevented. The hammer features an Enviro sealed and low-noise case. Another distinguishing feature of NPK demolition hammers is the thinner chisel diameter. This allows the chisel to penetrate the material more easily, ultimately resulting in very high production.