Large jaw type rock crushers are very common in the stone and gravel business. They are generally portable and can be towed by tractor trucks. The jaw crusher creates a pinch point that fractures larger rocks and reduces them to about the size of your fist. They are further crushed in a cone crusher and reduced to gravel as small as 1/4 inch.
The jaw crusher has two large flywheels powered by a diesel engine that spins an eccentric which causes a crush plate to oscillate making a pinch point fracturing rocks. The flywheels are indexable and have bolt-on plates to adjust the counterweight size to compensate for wear.
From a balancing standpoint, the crusher acts very much like a one cylinder engine. The counterweights in the flywheels act exactly as the counterweights in a crankshaft. The theory for adjusting the counterweights is identical.
Single cylinder engines are balanced to 50%. That means a bob weight is placed on the crankshaft that represents 50% of reciprocating weight, added to 100% of rotating weight. Reciprocating weight is 50% of, one piston and wrist pin and top of connecting rod, added to 100% the bottom of the connecting rod That weight is clamped to the crankshaft journal. The crankshaft is now balanced with the flywheels and the counterweights are adjusted for phase and amount.
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Large stationary jet fuel-powered turbines are the solution for many industrial applications where large amounts of rotational energy is needed in a comparatively small and compact package. As evident in commercial airline applications, the design constraints and the engineering solutions provided by jet turbine power, allow these motors to be used in a variety of relatively portable applications.
At HI-TEK Balancing, Inc, we have set the industry standard for solving vibration problems that arise in turbine engines and are implemented in new portable applications during the design and installation stages. These applications where large power density is required include cruise ships, large oil tankers, large cargo ships, and military vessels. Turbine engines must be mated to either a generator or directly to a propeller via a transmission. The shafts that are used to connect these devices are often unique to the application of the turbine. Turbines are balanced by the manufacturer, but the unique connecting shafts require balancing due to error generated by the realities of the shaft manufacturing tolerances and reassembly fit-up error.
With the assumption that the majority of vibration is caused by unbalance of the shaft, the shaft vibration is measured by reading the orbital acceleration data at the ends of the shafts. Technically speaking, four accelerometers are attached to the turbine engine, two horizontal, two vertical. Four additional accelerometers in the same orientation are attached to the receiving end, gearbox or generator, depending on the driving method of the particular ship.
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