Releasable stationary plate for rheometer

A sample plate assembly for a rheometer of the type used for testing the melt viscoelastic properties of a material sample, the rheometer having a rotary drive with a drive shaft selectively switchable between a continuous rotation and an arcuate oscillation, the sample plate assembly comprising:

• a movable plate adapted to be coupled to the drive shaft;
• a stationary plate assembly adapted to be coupled to the frame in juxtaposition with the movable plate such that the material sample is contained between the movable plate and stationary plate assembly, the stationary plate assembly having
• a support member coupled to the frame,
• a sample plate, and
• means for releasably coupling the sample plate to the support member, whereby the movable plate, the sample material and the sample plate may be separated as a unit from the support member, thereby allowing the movable plate, the sample material and the sample plate to rotate with respect to the support member as may occur when selectively switching the drive shaft between the continuous rotation and the arcuate oscillation.

A rheometer of the type used for testing the melt viscoelastic properties of a material sample comprising:

• a frame;
• a rotary drive mounted on the frame, the rotary drive having a drive shaft selectively switchable between a continuous rotation and an arcuate oscillation;
• and
• a sample plate assembly including
• a movable plate coupled to the drive shaft, and
• a stationary plate assembly coupled to the frame in juxtaposition with the movable plate such that the material sample is contained between the movable plate and stationary plate assembly, the stationary plate assembly having
• a support member coupled to the frame,
• a sample plate, and
• means for releasably coupling the sample plate to the support member, whereby the movable plate, the sample material and the sample plate may be separated as a unit from the support member, thereby allowing the movable plate, the sample material and the sample plate to rotate with respect to the support member as may occur when selectively switching the drive shaft between the continuous rotation and the arcuate oscillation.

A method of testing the molten viscoelastic properties of a material sample with a rheometer, the material sample being located between a rotatable plate coupled to a drive shaft and a stationary plate coupled to a support member on a frame of the rheometer and held immovable with respect to the rotatable plate, the drive shaft being connected to a rotary drive mounted on the frame, the rotary drive being switchable to selectively move the drive shaft in first, a continuous rotation and second, an arcuate oscillation, the method comprising:

• switching the rotary drive to select the continuous rotation of the drive shaft;
• moving the drive shaft and the rotatable plate in the continuous rotation;
• stopping the continuous rotation of the drive shaft and rotatable plate;
• moving the stationary plate relative to the support member on the frame to separate the stationary plate from the support member to create a unitary assembly of the rotatable plate, the material sample and the stationary plate coupled to the drive shaft and movable as a unit with respect to the frame;
• switching the rotary drive to select the arcuate oscillation of the drive shaft;
• moving the stationary plate relative to the support member on the frame to join the stationary plate to the support member;
• and
• moving the drive shaft and the rotatable plate in the arcuate oscillation.