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2013FallShotcreteEMag

Nozzleman Knowledge the gear box by accessing a dipstick. Check this General maintenance on a daily basis will oil level regularly, for example, after every 40 prolong the life of your gunite machine. Be sure hours of operation. to disconnect the air line from the air compressor Gunite machines include material screens and bleed off any remaining air in the system placed over the hopper to help prevent the intro- when performing any maintenance on the duction of aggregates larger than the machine is machine. Do not reach down into the hopper when designed to process. Typical bowl-type gunite the air line is connected because the agitator could machines can process aggregates up to 3/4 in. begin rotating, causing a dangerous situation. If (20 mm). It is common for material to build up air is flowing to the gunite machine and a valve on the material screen over time, which can reduce is opened, that incoming air could cause rotation the size of the spaces in the screen. This may not of the feed system, including the agitator—this is be cause to worry because you want to prevent no place for your hands or arms. oversized rocks from entering the hopper. Keep Certain areas of the gunite machine will material screens in good repair so they function require daily cleaning. Some models may include as designed, and keep them in place over the an exhaust chamber to catch dust and prevent it hopper to help avoid accidents with the rotating from rising out of the hopper. This item is not agitator inside the hopper. necessarily considered a wear item, but it is Within the feed system, a piece of metal called important to keep it emptied out each day. Clean a rock shear is present to catch any large rocks that any built-up material from the inside of the hopper may have accidentally gotten into the machine. If a base, which could catch on the feed bowl and large rock comes into contact with the rock shear, prevent rotation. Clean the main shaft and base- the feed system will not rotate and you will need to plate daily to ensure a smooth rotation of the feed shut down the machine to remove the rock. The rock system. An exhaust hose may be connected to the shear is in direct contact with material flow so it is machine to further reduce dust in the working a wear item. Check the rock shear on a weekly basis. environment, which helps to provide workers with It can be rotated four times to place a clean edge in the cleanest, most breathable air. contact with material. You will also need to adjust the rock shear to the correct distance from the wear Dry-mix Shotcrete plate during setup. (Gunite) Nozzles Dry-mix nozzles are designed to receive dry or pre-dampened material from the gunite machine and water from a source with adequate pressure. The two components mix together at the last moment before they are propelled onto the construction surface. Nozzle maintenance is important for achieving proper mixing of water and material within the nozzle. The water ring is the most impor- tant part of the nozzle to keep clean. The water ring, which may be brass or aluminum, includes holes to allow water to pass through at high pressure into the nozzle body during operation (Fig. 6). Be sure to Fig. 5: Gunite machine components inspect the water ring before a job to make sure these holes are free and clear from any buildup. Manu- Fig. 6: New water ring (left), worn water Fig. 7: Dry-mix nozzle components (showing ring (right) “double bubble” style tip) 40 Shotcrete • Fall 2013


2013FallShotcreteEMag
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