bcsinnovations

(Image of Griggs Laboratory at Macquarie University)

BCS has been helping researchers at Macquarie University with their study of rocks which deform and flow under extreme conditions of temperature and pressure. These types of experiments have been critical to advancing our knowledge of our planet, as they allow us to simulate regions that are inaccessible, such as the earth's deep crust and mantle.

The Experimental Petrology and Rock Deformation Griggs Laboratory in the Earth and Planetary Science Department at Macquarie University has for some time been researching magma production and how magmas escape from their source. Laboratory experiments on natural rocks are helping to determine the variables controlling melting, melt segregation and the rates of these processes. In order to further their research, The laboratory asked BCS Innovations to design a custom data logging and control system to integrate with their Griggs Press apparatus, which can subject rock samples to temperatures in excess of 1000C and pressures of 25,000 atmospheres.

The system was designed by BCS engineer Nathan Parrot and was implemented using National Instruments hardware integrated into a cDAQ-9172 backplane, with software and a graphical user interface for control and feedback designed using Labview 8.0. Data from the experiment is displayed graphically in real time, and also logged for post-experiment analysis.

The control system:
- regulates the furnace temperature between 20C and 1500C. This is done via mains phase control on a 2.4kVA transformer (300A at 8V) supplying power to a heater,
- controls an electronic ram (which produces the principal “σ1” stress in the rock sample) using a relay and digital outputs, and
- controls a hydraulic ram (which produces the secondary “σ2 and σ3” stresses) using a solenoid valve and digital outputs.
The data logging system acquires data from a variety of sensors, including:
- a platinum-rhodium thermocouple to measure sample temperature,
- several sensors to measure sample strain and stress, including:
load cell for the electronic ram,
hydraulic pressure transducer for the hydraulic ram,
a DC LVDT displacement sensor,
- a Hall effect sensor and custom electronics to measure heater current and voltage, and
- a fluid flow sensor to monitor cooling water flow
The completed system was successfully commissioned in December 2009. An example of the experimental data produced by the system is shown below.

Both BCS Innovations and the Experimental Petrology and Rock Deformation Griggs Laboratory are very pleased with the functionality of the system and we hope that it will contribute greatly to the field of magma production and release research. For more information on the experimental work in this field, visit: www.gemoc.mq.edu.au/ExperimentalPetrol/ExperimentalPetrol.htm