United Equipment Accessories has been designing a test stand to run accelerated life testing on our hydraulic swivels. The purpose of UEA having this accelerated in-house testing capability is to provide our valued customers with the hard reliability facts and recorded data results based on their specific application conditions and operating testing parameters, before our designs and end products hit the customer's production floor.
We’ll soon be moving into the fabrication phase. Listed below are some of the key points that this test stand will be offering.
- The overall footprint of this piece of equipment is 87” wide x 54” deep x 96” high. It contains the test stand which is 48” wide X 48” deep x 96” high; the test chamber itself where the actual testing is done is 40” x 40” x 50”. Front and top doors are manually opened for the installation and removal of the swivel assemblies. The test chamber is enclosed using polycarbonate sheet and expanded flattened sheet metal on all sides. There’s also a 25-gallon reservoir along with three electric motor-hydraulic pump units.
- During various continuous pressure cycles, the swivel assembly is rotated by a hydraulic motor, having the capability to produce up to 1500 ft-lb of torque. This motor is driven by an electric motor-pump combination unit. The hydraulic motor and a torque arm are assembled to a turntable which allows for degrees of freedom. The torque readings are measured by a load cell connected between the torque arm and ground. The swivel rests on a drive plate which has two drive pins that rotate the spool. The rotational speed of the swivel will vary between 2-10 rpm. The housing is constrained to the frame of the machine with height adjustment square tubes. These are positioned for each individual swivel using acme screws along with a series of gearboxes. The frame is gusseted to handle the forces produced during the rotation of the swivel while the hydraulic passages are held under the high pressure test cycles.
- Hydraulic pressure testing of the swivel will have three pressure ranges and are accomplished by using two electric motor-pump units. One controls the low and medium pressures while the other controls the high pressure range up to 5,000 psi. The pressures will alternate during the specified testing criteria to simulate the actual field operating functions of the swivel.
- A data acquisition system will measure and record torque and pressure cycles during the testing process. We’ll be looking for pressure decay and any major variations in our torque readings during the testing. The ongoing testing period will be monitored 24/7 both on and off site.
- The cold start up test is done at -40 degrees Fahrenheit and is accomplished by either cold soaking the swivel with liquid nitrogen or packing it with dry ice. The larger swivels will be cold soaked while the smaller ones will be packed with dry ice. The swivel will also be tested at 220 degrees Fahrenheit using heat blankets or heating cartridges. The temperature variations will be measured by using thermocouples.
- The test stand has a 25-gallon reservoir and will be water cooled. The liquid level and temperature in the reservoir will be monitored. Liquid cleanliness will also be monitored with an ICM and maintained at the ISO 4406 requirement.
In summary, below are just some of the true advantages and values of performing these accelerated, controlled product reliability testing methods.
- The benefit of having an accelerated proof of reliability based on the positive test data results will provide the customer with the confidence of early validation of the product performance, inherent quality and will allow the customer an earlier new product release onto the market place.
- Establishing a baseline product reliability testing requirement for pre-qualifying a new or potential supplier for a new product can speed up the supplier selection process and help to ensure that the supplier is capable of providing the highest quality.
Thomas Van Veldhuizen
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