Rotor for rheological measurements of material with variable volume
A rheological system includes a sample chamber, a compressed air system configured to provide compressed air to pressurize the sample chamber, and a rotor configured for rheological measurement of a material with variable volume, the rotor including an elongated shaft extending to a measurement portion having a widened geometry relative to the elongated shaft. The rotor is dimensioned such that a compression ratio of at least 5 to 1 is achievable while maintaining material cover of the sample over the entirety of the measurement portion of the rotor, the compression ratio being defined by a decompressed volume of a sample when the sample chamber is not pressurized to a compressed volume of the sample when the sample chamber is pressurized. Methods of taking rheological measurements with such a rotor are also disclosed.
1. A rheological system comprising:
a sample chamber;
a compressed air system configured to provide compressed air to pressurize the sample chamber;
a rotor configured for rheological measurement of a material with variable volume, the rotor including an elongated shaft extending to a measurement portion having a widened geometry relative to the elongated shaft;
a parallel visualization chamber connected to the compressed air system, the system configured to maintain the parallel visualization chamber at the same pressure as the sample chamber; and
a camera configured to detect images within the parallel visualization chamber.
2. The rheological system of claim 1 , wherein the measurement portion is cylindrical and includes a circumference and a thickness, wherein the circumference is less than a circumference of the sample chamber and greater than a circumference of the elongated shaft.
3. The rheological system of claim 2 , wherein the measurement portion includes a cylinder wall having vertically oriented straight knurls.
4. The rheological system of claim 2 , wherein the measurement portion includes a plurality of outwardly protruding vanes disposed vertically about the circumference of the cylindrical measurement portion.
5. The rheological system of claim 2 , wherein the circumference of the cylindrical measurement portion is greater than twice the circumference of the elongated shaft.
6. The rheological system of claim 5 , wherein the thickness of the measurement portion is less than ⅕ of a length of the elongated shaft.
7. The rheological system of claim 6 , wherein a space separates a bottom of the measurement portion and a bottom of the sample chamber, and wherein the space has a height that is less than a difference between a radius of the elongated shaft and a radius of the sample chamber.
8. The rheological system of claim 1 , wherein the rotor further includes a first end and a second end, the rotor further including a circumferential plate located at the first end, wherein the measurement portion is located at the second end.
9. The rheological system of claim 1 , further comprising an air pressure line connecting the sample chamber and the parallel visualization chamber.
10. The rheological system of claim 1 , wherein the system is further configured to maintain the parallel visualization chamber at the same temperature as the sample chamber.
11. A method of taking a rheological measurement of a sample of a material with variable volume comprises:
filling a sample chamber of a rheometer at least partially with the sample, wherein a rotor extends into the sample chamber, the rotor including an elongated shaft extending to a measurement portion having a widened geometry relative to the elongated shaft;
pressurizing the sample chamber;
maintaining material cover of the sample over the entirety of the measurement portion of the rotor during the pressurizing,
maintaining a parallel visualization chamber at the same pressure as the sample chamber; and
detecting images within the parallel visualization chamber during the pressurizing with a camera.
12. The method of claim 11 , further comprising connecting the sample chamber and the parallel visualization chamber with an air pressure line.
13. The method of claim 11 , further comprising maintaining the parallel visualization chamber at the same temperature as the sample chamber.