Cyclic Valve Testing Device

Photo of Zachary Ragsdale, Grant Russell, Michael Sangree, Michael Wallace Students: Zachary Ragsdale, Grant Russell, Michael Sangree, Michael Wallace

Sponsor: Chevron

Date: Spring 2012

Requirements:
The apparatus must to apply and measure a maximum of 15,000 ft-lb and a minimum of 100 ft-lb of torque. The apparatus must continually monitor the torque applied when manipulating the valve and transmit this data to a personal computer with an accuracy of ±5%. The apparatus must be driven hydraulically, with hydraulic pressure provided by an electrically driven hydraulic pump running on 120VAC or 240VAC, single or three phase. The apparatus must and/or close the valve by rotating the stem up to ninety degrees clockwise or counterclockwise as needed. The apparatus must open or close a valve within 30 seconds or less under full load. The speed of this stroke should be adjustable. Safety devices must be include to assure that the device operates safely and within a preset torque value. Wherever possible, commercial "off-the-shelf" parts and components were to be used in the apparatus.

Problem:
Design an apparatus to cycle a variety of quarter-turn valves, while continuously measuring the applied torque and collecting the torque data on a personal computer using a custom designed program.

Solution:
The team developed two solutions to the problem. The first uses a single hydraulic piston actuating a nonsymmetrical moment arm attached to an output shaft, while the second design is built around a heavy duty, commercial hydraulic Rack and Pinion Actuator. The Single Piston actuator is cheaper and lighter, with a system cost of approximately $12,000 and a weight of about 700lb. The Rack and Pinion Actuator by contrast is estimated to cost almost $30,000 and weigh 1,200lb. The Rack and Pinion Actuator is composed of almost entirely off-the-shelf components. Both mechanical systems require similar hydraulic. The control/ data acquisition system comprises several sensors, a data acquisition (DAQ) board, and the program that runs and monitors the entire device. National Instruments LabVIEW was used to implement the program. The Single Piston design uses a load cell to measure force, which is converted to torque by the DAQ program. The Rack and Pinion Actuator uses a torque cell to measure torque directly.

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