System and method for assessing rheological properties of grease

Patent metadata

Field	Value
Publication number	US-9778159-B2
Application number	US-201514819471-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Aug 21, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A system for investigating rheological properties of grease, the system including grease sample preparation arrangement for preparing a grease sample with a predetermined quantity of grease, at least two sample holder plates for holding the grease sample by sandwiching the grease sample between the sample holder plates, wherein at least one of the sample holder plates is transparent, and a loading system for generating a predetermined force acting on the grease sample sandwiched between the sample holder plates by pressing on the sample holder plates such that a spot formed by the grease sample on the sample holder plates is expanded. The loading system can include at least one transparent portion enabling a continuous observation of the expansion of the spot while the predetermined force is acting on the grease sample.

First claim

The invention claimed is:

1. A system for investigating rheological properties of grease, the system including:
a grease sample preparation arrangement for preparing a grease sample with a predetermined quantity of grease;
a first sample holder plate and a second sample holder plate for holding the grease sample by sandwiching the grease sample between the first and second sample holder plates, wherein at least one of the first and second sample holder plates is transparent; and
a weight for generating a predetermined force acting on the grease sample sandwiched between the first and second sample holder plates by pressing on the first and second sample holder plates such that a spot formed by the grease sample on the first and second sample holder plates is expanded, the weight including at least one transparent portion enabling a continuous optical observation of the expansion of the spot while the predetermined force is acting on the grease sample, and
further comprising a frame for aligning the first and second sample holder plates and the weight,
wherein the frame is configured to receive the second sample holder plate and allow movement of the second sample plate in a first direction toward the first sample holder plate while substantially preventing movement of the second sample holder plate in a second direction perpendicular to the first direction.

2. The system according to claim 1 , wherein the weight is made of glass.

3. The system according to claim 1 , further comprising a camera for recording the expansion of the spot.

4. The system according to claim 3 , further comprising a holding element for fixing the camera at a predetermined distance from the grease sample.

5. The system according to claim 3 , further comprising a data processing system configured to determine a size of the spot for a plurality of points in time from the data recoded by the camera and to determine a rheological parameter the grease sample based on the evolution of the size of the diameter of the spot over time.

6. The system according to claim 5 , wherein the data processing system is configured to calculate a spot diameter as a function of time and to determine a pumpability parameter quantifying the pumpability of the grease sample based on a time derivative of the spot diameter.

7. The system according to claim 1 , further comprising a temperature controlling system for controlling the temperature of the grease sample.

8. A system for determining rheological properties of grease, the system including:
a frame;
a first sample holder plate configured to support a grease sample and a second sample holder plate having a first side and a second side, the first side being configured to rest on the grease sample to sandwich the grease sample between the first sample holder plate and the second sample holder plate, the first sample holder plate and/or the second sample holder plate being transparent; and
a weight having a bottom configured to be supported by the second side of the second sample holder plate, the weight having a top and the weight having a transparent window through which light can pass from the bottom to the top,
wherein the frame is configured to receive the second sample holder plate and allow movement of the second sample plate in a first direction toward the first sample holder plate while substantially preventing movement of the second sample holder plate in a second direction perpendicular to the first direction.

9. The system according to claim 8 , wherein the frame is configured to receive the first sample holder plate and the weight and to allow movement of the weight in the first direction while substantially preventing movement of the first sample holder plate and the weight in the second direction.

10. The system according to claim 9 , wherein the frame includes a circular opening for receiving the first sample holder plate and the second sample holder plate and the weight.

11. The system according to claim 10 , further comprising:
a camera configured to capture a succession of images of the grease sample through the window at a plurality of time points;
a holder for fixing the camera at a predetermined distance from the grease sample; and
a data processing system configured to determine from the succession of images a rheological parameter of the grease sample.

12. The system according to claim 8 , wherein the window comprises glass.

13. A method for determining rheological properties of grease using the system according to claim 8 , the method comprising:
placing the grease sample on the first sample holder plate, the grease sample having a predetermined size and shape;
placing the second sample holder plate on the grease sample;
placing the weight on the second sample holder plate; and
continuously observing an expansion of the grease sample through the window and deriving at least one rheological property of the grease sample from the expansion of the grease sample over time.

14. The method according to claim 13 , wherein the continuously observing comprises capturing images with a camera.

Assignees

• D'Antona Egidio
• Lugt Pieter Martin
• Nedelcu Ileana
• Pasaribu Rihard
• Van Der Vorst Albertus Maria
• Skf Ab

Inventors

• D'Antona Egidio
• Lugt Pieter Martin
• Nedelcu Ileana
• Pasaribu Rihard
• Van Der Vorst Albertus Maria

Classifications

• G01N11/02 Primary

  by measuring flow of the material · CPC title

• G01N2011/008

  optical properties · CPC title

• G01N11/04 Primary

  through a restricted passage, e.g. tube, aperture · CPC title

• G01N33/30

  for lubricating properties · CPC title

• G01N11/00 Primary

  Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties · CPC title