Conforming to international standards, the Mk III is a shearing-disc viscometer in which the rubber sample is compressed pneumatically in a cylindrical chamber formed by cavities in 2 opposing dies.
The viscosity is determined by measuring the torque required to turn the rotor inside the chamber, heated to a set temperature. As the rotor shears the sample, a torque reaction is transmitted through a worm shaft, which deflects a torsion beam. A dial gauge (analogue or digital) measures the beam’s displacement.
With its simple mechanical drive system and well-proven design, the Mk III has been in use for many years and has become the benchmark viscometer for thousands of laboratories.
In May 2000 Wallace purchased the exclusive rights from Negretti Automation to manufacture the Mark III Viscometer. For selected overseas markets, Wallace have since developed an upgraded Mark III Viscometer, featuring modern control electronics, a safety guard and new PID temperature controllers with digital displays. The well-proven electromechanical features of the original Mark III design remain unchanged.
Four versions are offered:
V3/1 Basic model with analogue dial gauge and no LCD display
V3/2 All digital output including LCD display
V3/3 As V3/2 with 24 column printer
V3/4 As V3/2 with serial port for automatic data transfer to PC
Large and small diameter rotor, set of tools
Calibration Kit, S1 Specimen Cutting Press, air compressor, calibrated butyl rubber for rapid check of viscometer
|LED screen, (excl. V3/1)||2 line, 20 character back-lit display housed in control panel|
|Controls||3 sealed switches with integral LED indicators|
|Gauge, (excl. V3/1)||0.0 – 0.5 ̋ range. 0.0005 ̋ resolution.|
|Dimensions||510 x 460 x 810mm (w x d x h)|
|By elements to upper and lower platens. 700W per element
80 – 150°C ( ±0.5°C)
|Max. torque||Cut out at 200 Mooney points|
|Die closure||By pneumatic cylinder|
|Air line pressure||5.6 Bar|
|Pressure controls||Twin controls for platen closure and test routine|
|Standards||BS 903 Pt.A58, ASTM D1646, ISO 89, NFT 43 005, DIN 53 523, JIS K6300|