FLUSHING HEAD (1+2) Flushing heads for double-tube jet grouting systems provide the connection point to the drill string for flushing media during drilling, as well as for high-pressure grout and air during grout injection. The JG Head consists of a basic head and a flange that connects to the drill rod. Flushing heads are mounted to a flushing head carrier, which allows the head to move up the mast extension on the rig.

ROD (3) Double tube jet grouting rods are used during rotary drilling for flushing as well as the path to the nozzles for the high-pressure grout injection. Rod ends are constructed of high-strength nitrided steel and friction-welded to an annealed mid-body. Inner tubes in the dual-tube systems are secured inside the outer rod using a circlip or wire fuse connection. Rods come with special seals between them, which resist damage from abrasive grouts and multiple cycles of making and breaking rod joints.

VALVE FASTENER (MONITOR) (4) The valve fastener (also called a monitor) mounts between the drill rod string and the drill bit. The valve fastener contains the injection nozzles as well as the automatic valve. The valve fastener channels the medium from the inner drill string and outer rod to their associated nozzles.

AUTOMATIC VALVE (5) The automatic valve is located within the valve fastener and controls the flow of both low-pressure flushing fluids and high-pressure grouting media. During the drilling operation, the spring-loaded automatic valve allows for flushing fluids to pass out through the drill bit. When high-pressure grout is introduced into the drill string, the automatic valve will close, directing the jet grouting media and air out through the injection nozzles in the valve fastener. The pressure can be adjusted before drilling starts, when the jet grouting valve closes.

INJECTION NOZZLE (6) The grout injection nozzles mounted in the valve fastener are the exit points for the high-pressure grout into the grouting zone. Injection nozzles are constructed with a tungsten carbide body with a threaded steel base. The nozzles are available with various sizes with either a standard round injection orifice or a ribbed injection orifice. The ribbed orifice creates an injection with less turbulence from a more compact jet.

AIR NOZZLE (7) The air nozzles mounted in the valve fastener are the exit point for the low-pressure phase into the grouting zone. The compressed air reduces the spray effect, resulting in a more focused, piercing jet.

ROTARY BIT (8) The rotary bit for a double tube jet grouting system mounts below the valve fastener. They are designed for rotary drilling only in overburden. They come in a variety of winged bit designs with tungsten carbide inserts and flushing ports.