Rockland Research - Piston Cylinder Systems

Rockland piston-cylinder system configured in one of our 250 ton presses. The stack components are above and below the pressure vessel, shown here with a set of handles which allow for easy maneuverability. Press dimensions are 72"h x 36"w x 30"d. Rockland pressure vessels and presses for use up to 35 kbar are available. We supply presses of several sizes, depending upon your needs, including table-top units (below).

A Rockland piston-cylinder system consists of a press, pressure vessel, stack components and associated hydraulic control systems. A simple schematic cross-section of an apparatus is shown in the diagram below. In the diagram, the end load ram and main hydraulic ram are part of the press (not shown), while the remainder of the components, excluding the pressure vessel, are part of the "stack."

The heart of the apparatus is the pressure vessel, which contains a tungsten carbide (WC) core supported by concentric rings of hardened steel, following the time-tested Boyd and England design. The sample assembly (red) is compressed in the core of the vessel by a WC piston (brown), driven by a WC push piece (dark grey). The force is provided by the main hydraulic ram acting against the sample assembly and stack top plate, which is confined by an end load applied by the upper hydraulic ram.

Upon application of the end load, the sample is pressurized in minutes with an electrically-operated hydraulic pump driving the main ram. The system is calibrated by measuring the pressure dependence of some material property (e.g., resistance) through the well-established phase transitions of different materials. Temperatures as high as 2000°C or more can be achieved by passing a current through a cylindrical heater in the sample assembly. Although not explicitly depicted in the diagram, coolant circulating through the stack top plate and bridge during high temperature operation is used to minimize thermal stresses in the pressure vessel. In addition to the press and hardware shown above, Rockland can supply both pressure and temperature controllers for your experiments.