Robert Sheaf

CFC Industrial Training

Robert J. Sheaf Jr., is the founder and president of CFC Insustrial Training, formerly Certified Fluid Consultants, part of CFC-Solar Inc. CFC-Solar provides technical training, consulting, and field services to any industry using fluid power technology. 

Troubleshooting Challenge: Pump Keeps Losing Its Prime
Why wouldn’t the hydraulic pump hold its prime, and why did the flapper check blow out?
Troubleshooting Challenge: Pump-housing Cracking
A paper mill’s pump showed extensive piston barrel and shoes damage. But what caused it?
Troubleshooting Challenge: Speed Control Causing Unwanted Jolt and Pressure Spike
A casting plant used a simple two-speed circuit to extend a hydraulic cylinder at high speed, then shift to a slower speed for forming. The maintenance supervisor used the accompanying schematic to plumb the circuit.
Troubleshooting Challenge: Unexpected pressure loss while testing a new hydraulic power unit
In preparing for a retest of a hydraulic power unit experiencing quick pressure drops/rises, the oil was drained from the reservoir and panels removed, only to discover construction debris and beads of excess pipe dope at the bottom of the reservoir.
Troubleshooting Challenge: Hydraulic system causes structural failure
I was asked to examine and review the circuit design on a walking-beam conveyor system in a pipe mill that had one of two lifting cylinders suddenly drop. This caused one side of the structural frame to fracture, dropping a 60,000-lb coil of ½-in. steel into a pit.
Troubleshooting Challenge: Eroded Construction Plug Causes Manifold Leak
A mill that produces oil-field pipe is required to hydrostatically test the pipe with water according to ASTM standards. They used a hydraulically driven water intensifier to fill and test the pipe at pressure to 2,500 psi.
Troubleshooting Challenge: Hydraulic Motor Presents Problem on Coal Conveyor 2
A power plant has a conveyor that carries coal from a barge on the Ohio River to a storage pile. The beginning of the conveyor starts 10 ft below ground level and carries material up about 40 ft above the ground.
Troubleshooting Challenge: Drifting Cylinder Problem 3
A hydraulic system was designed and sold by a new sales engineer. The application required an ejector cylinder to remain fully retracted for a dwell period while the molded part cured. Once the part was fully cured, the cylinder would extend to eject the part...
Troubleshooting Challenge: Flow dividers keep breaking
An older four-post vertical press with a 6-ft daylight opening was designed with one cylinder on each corner of its platen. The cylinders extended to close the press and retracted to open. To keep the platen somewhat square and parallel with the press’s bed plate, a four-section gear-type flow divider was used to feed the cap end of the four cylinders.
Troubleshooting Challenge: Proportional-Valve Inconsistency
A simple circuit was designed to lift large castings on an elevator from a conveyor at floor level to another conveyor located high in the building. The elevator used a pressure-compensated pump with a three-position proportional-directional valve, filters, and a relief valve for safety.
“Root beer” foam coming from filler breather
A technician at a plant that uses large three-axis milling machines explained that one of the machine’s hydraulic power units had foam coming out of the reservoir’s filler breather and the HPU was quite noisy. He observed the foam oozing out when a large cylinder retracted, and noise was normal. However, when the same cylinder extended, noise increased but the foaming stopped.
Cylinder failures on a pipe-fabrication machine 1
A company that fabricates oil-field pipes starts with flat steel, rolls it into a round tubular shape, and simultaneously welds the inside and outside surfaces of the joined ends. Tooling removes excess weld material, creating a round pipe that actually looks like seamless pipe. A cutoff station then cuts the pipe coming off the production line to 21-ft lengths.
Production boost causes seal leak

An original-equipment manufacturer of custom automation equipment for the food-processing industry built a large pallet-transfer system to shuttle bins of poultry from a defeathering line to a final processing line. The poultry was placed into bins, 10 at a time, and the bins were stacked 10 high. The 10-high pallet-transfer system consisted of a floor-mounted rack-and-pinion drive system with a gerotor motor driving the pinion to move the pallets. The pallets were then shuttled to one of three locations to be off-loaded for final processing.

Oil rig has overheating problem
Oil rig has overheating problem
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