Load cells and other loading devices with capacities up to 13 MN (3,000,000 lb) in either tension or compression can be calibrated in the Southwark-Emery and Riehle testing machines. Calibrations are traceable directly to the National Institute of Standards and Technology (NIST) in Gaithersburg, Md.
Largecapacity load cells
Large-capacity tension load cells are placed between the upper and lower crossheads of the Southwark-Emery testing machine. Adapters furnished by the customer or machined in the AE Machine Shop are then secured by the V-grip or flat-faced grips in the crossheads. A Tate-Emery load cell that is part of the lower crosshead is used to monitor the NIST-traceable force applied to the customer’s load cell.
Large-capacity compression load cells are placed directly on the lower platen of the Southwark-Emery testing machine, then loaded by the upper platen. These platens are 0.9 m (3 ft) in diameter and are ground flat to within 0.025 mm (0.001 in.). The same Tate-Emery load cell that is used for tension is used to monitor the NISTtraceable force applied to the customer’s compression load cell.
The Southwark-Emery testing machine can also be used to calibrate large-capacity hydraulic rams (jacks) with or without load cells. Rams up to 13 MN (3000 kips, or 1500 tons) capacity can be calibrated. The customer furnishes the hydraulic power unit and pressure gage(s) for the ram, while the Tate-Emery load cell in the lower crosshead is used to monitor the NIST-traceable ram load.
Smallercapacity load cells
A Riehle 890 kN (200 kip) testing machine with an NIST-traceable compression load cell can be used to calibrate customers’ compression load cells in the sub-200 kip range. A similar direct-loading tension calibration setup is currently under development.