In asphalt laboratories the Digital Vacuum Regulator (DVR)
may be used in conjunction with Cannon-Manning, Asphalt Institute, and Modified Koppers vacuum viscometers for measurement
of highly viscous materials such as asphalt cement at 60°C (140°F) according to
ASTM D 2171. The DVR is also useful in other laboratory systems where accurate
measurement and control of vacuum is required.
Two basic versions of the DVR are
available. The DVR-1500 is equipped with an internal vacuum
pump and does not require an external vacuum source. The
DVR-1000 uses the customer’s in-house vacuum system.
The internal set points for the
instrument gauge are preset at CANNON to regulate vacuum at
300 ± 0.5 mm Hg below atmospheric pressure (the vacuum
required by ASTM D 2171). These set points may be altered to
fit the user’s specific needs within the DVR’s operating
range of 28 to 410 mm Hg below atmospheric pressure.
Both the DVR-1000 and DVR-1500 are available in either
horizontal or vertical configurations (the horizontal version will support the
weight of a constant temperature bath like the CANNON CT-1000 or CT-2000).
The instrument housing is made of durable enameled steel
and is supported on non-slip rubber feet.