United Equipment Accessories' hydraulic test stand is made up of a hydraulic power unit (HPU), electrical and electronic control system and the swivel test stand itself.
The HPU contains a return tank and main reservoir both which have a capacity of 20 gallons. The return tank consists of, a strainer, motor and pump, fluid level and temperature switches and two filters. One filter removes water and the other removes solids from the fluid. The main reservoir consists of, a motor and pump, a cooler, fluid level and temperature switches, and a manifold block with solenoid valves. A drip pan serves as the support stand and houses both tanks. An ICM monitors the cleanliness of the fluid at a level of 18/16/13. A remote control valve is used to manually set the test pressure for the swivels. The manifold block with solenoid valves controls the supply of the fluid to the test stand components.
While the HPU controls all things fluid, the electrical and electronic control system monitors and controls the inputs and outputs for the machine operations. It consists of an electrical enclosure and provides power to the components on the swivel test stand and the HPU. A data acquisition system monitors and records data on the air and hydraulic pressure, torque, and fluid cleanliness during testing. Commands on the computer screen are selected to perform the designated testing functions.
The hydraulic swivel test stand itself is an enclosed structure with two chambers. The lower chamber contains the swivel drive, and the upper chamber is for testing the swivels. The swivel drive has a hydraulic motor, planetary in-line gearbox, and a drive shaft and hub. The gearbox has the capacity for a continuous output torque of 24,000 in-lbs or an intermittent output torque of 48,000 in-lbs. The pneumatics system serves the purpose of running the air pressure test and purging the oil from the swivel. In it, there are two air filters that remove impurities from the air. The pressure is set at 90 psi for the air test and a pressure transducer monitors and records data every 5 seconds over the 90 second test. The hydraulic test system contains, a booster, four in-line check valves (zero leak), four six-station manifold blocks, and two piloted check valves (zero leak), four hydraulic cylinders and two load cells.
During testing, the swivel is pre-filled and the doors are closed before the swivel is brought up to test pressure. The proximity sensors detect that the cylinders are retracted and that the doors are closed. The booster controls the test pressure of the swivel to four times the pressure set at the remote control valve and can provide up to a maximum output pressure of 7500 psi from a set pressure of 1875 psi. The test pressure is 1.5 times the maximum swivel operating pressure; up to the limits of the booster. All the odd circuits are tested simultaneously and then all the even ports. Two pressure transducers measure the pressure on the odd circuits and the even circuits. The data for the pressure drop on both circuits is recorded every 5 seconds over the 150 second test. Each swivel is rotated both clockwise and counterclockwise; under load and under no load. The force to rotate the swivel under load and under no load is recorded by two load cells and then converted to torque. The cleanliness of the hydraulic fluid is continually monitored during testing. After testing the oil is purged from the swivel using clean air sending the oil back to the Return Tank. This robust UEA test stand can test twelve circuits in one set-up and handles a swivel that’s up to 18.00″ in diameter and 30.00″ in long. This test stand ensures a quality, no leak swivel every time.
Tom Van Veldhuizen
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