The Holte Casing Driver (CD) was designed to be small and compact as well as hard hitting like a Down Hole Hammer (DHH). While the CD cycles fast like a DHH it is able to be designed around a much larger piston since it is above ground, in turn, deriving an extremely powerful impact for driving casing, allowing your DHH to run most efficiently since its energy is not absorbed trying to pull casing along with it.
The Holte Casing Driver is designed to be used with a DHH (Down The Hole Hammer) and underreamer, and is available in four sizes from an easily portable size for light duty rigs to a heavy duty size for the most extreme well and hole conditions.
The casing drive acts similar, in operation, to a down hole hammer. When the hole is first started and until gravity is not enough to make the casing follow the underreamer the casing driver sits inactive on top of the casing and acts as a water diverter. When the underreamer advances 1” ahead of the casing the CD anvil closes and the casing driver starts operating. The more the anvil is closed, the harder the casing driver hits. This happens when increased air pressure and volume feeds the casing driver which makes the piston operate faster and harder. The CD turns on and off automatically and runs only when the casing lags behind the underreamer, causing the anvil to close. There is only 1 1/4” of vertical movement of the CD anvil so the casing will always remain within 3” of the bit.