Foam assessment

• US 20060210139A1
• Filed: 02/24/2004
• Published: 09/21/2006
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Imperial Chemical Industries Limited (Nouryon BV)
• Original Assignee: Imperial Chemical Industries PLC (IMPERIAL CHEMICAL INDUSTRIES)
• Inventors: Meredith, William Neville Eugen, Carroll, John, Shadforth, Pamela Yvonne
• Granted Patent: US 7,693,322 B2
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G01N 13/02 Investigating surface tension of liquids
• CPC Class Codes: G01N 15/0227 using imaging; using holography
• CPC Class Codes: G01N 2013/025 Measuring foam stability
• CPC Class Codes: G01N 2015/0011 in liquids, e.g. bubbles
• CPC Class Codes: G01N 21/51 inside a container, e.g. in an ampoule G01N21/53 takes precedence
• CPC Class Codes: G01N 33/14 Beverages
• CPC Class Codes: G01N 33/143 containing sugar
• CPC Class Codes: G01N 33/146 containing alcohol
• CPC Class Codes: G01N 33/28 Oils , i.e. hydrocarbon liquidsgaseous fuels G01N33/225; edible oils or edible fats G01N33/03
• CPC Class Codes: G01N 35/0099 comprising robots or similar manipulators robots per se B25J
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes

Abstract

There are described methods and apparatus for assessing foams generated from liquids. Existing methods are slow and labour intensive. The new methods involve generating foams from liquids and optically obtaining information to enable parameters relating to the generated foam to be measured. Although single samples of liquids may be processed the methods are particularly suited to processing multiple samples to obtain data relating to foams at a high rate. The apparatus includes automated handling equipment to enable samples to be moved between workstations and relative to associated optical equipment that is used to obtain information relating to the foams.

Claims

1. A method of assessing foam generation from a liquid comprising:

a) introducing a measured quantity of the liquid into a tube;

b) after a predetermined period, generating a gas flow of predetermined flow rate into the liquid to generate a foam from the liquid in the tube;

c) using an optoelectronic device capable of generating data relating to foam in the tube to obtain data relating to the foam generated in the tube; and

d) using the data to assess the foaming ability of the liquid.

2. The method according to claim 1 further comprises passing the gas through the liquid for a predetermined period unless data from the opto-electronic device indicates the presence of the top of the foam being generated before said period expires.

3. The method according to claim 1 further comprises passing the gas through the liquid for a predetermined period unless data from the opto-electronic device indicates the presence of the top of the foam being generated before said period expires whereupon gas flow is terminated and;

if the data from the opto-electronic device does not indicate the presence of top of the foam before said period expires, on expiry of said period stopping the gas flow and moving the tube and the opto-electronic device relatively with respect to one another to enable data to be obtained from the opto-electronic device to determine the height of the foam generated in said period

4. The method according to claim 3 in which the opto-electronic device generates data relating to the positions of the air/foam and the foam/liquid interfaces, the difference between the positions of said interfaces being the height of the foam generated from the liquid in said period.

10. The method according to any one of the preceding claims in which a plurality of samples are assessed either sequentially or in parallel.

11. The method according to any one of the preceding claims in which, in parallel assessment, more than 1 sample but not more than 100 samples, more preferably at least 10 samples but not more than 50 samples are processed together.

5. A method of assessing the quality of foam generated from a liquid comprises:

a) introducing a measured quantity of liquid into a tube;

b) after a first predetermined period, generating a gas flow of predetermined flow rate into the liquid to generate a foam from the liquid in the tube;

c) after a second predetermined period, stopping the gas flow and measuring the height of the foam generated in the tube;

d) in response to the height data generated in step c), positioning an opto-electrical device a location externally of the tube by relative movement of the tube and the opto-electronic device with respect to one another, the device being capable of capturing an image of the foam;

e) capturing an image of the foam; and

f) analysing the captured image for parameters relevant to foam quality.

6. The method according to claim 5 in which the height of the foam generated in the tube is determined using a second optoelectronic device capable of generating data relating to foam in the tube.

7. The method according to claim 6 comprising moving the tube and the second optoelectronic device relatively with respect to one another to enable a determination the height of the foam generated in said period to be made.

8. The method according to claim 7 in which the second opto-electronic device generates data relating to the positions of the air/foam and the foam/liquid interfaces, the difference between the positions of said interfaces being the height of the foam generated from the liquid in said period.

9. The method according to claim 6 comprises using the second opto-electronic device to capture an image of the foam and analysing the image to determine the height of the foam generated from the liquid in said period.

12. A method of analysing an image of foam generated from a liquid comprises subjecting a digital, black and white image (image 1) of the foam to the following operations:

a) subjecting image 1 to a watershed segmentation process to produce an image (image 2) in a graphics plane associated with the electronic frame, image 2 being a line representation of bubble walls of the foam;

b) clearing image 1 from the image plane of the frame and merging the graphics plane with the image plane of the frame to create a binary image (image 3) consisting of lines representing the bubble walls and a contrasting background and clearing image 2 from the graphics plane; and

c) measuring the dimensions of the bubbles.

13. A method according to claim 12 in which, in step b), in image 3 the lines are white and the background is black.

14. A method according to claim 13 in which, before step c), image 3 is inverted to create image 4 in which the bubble walls are black and the bubbles are white.

15. A method according to any one of claims 12 to 14 in which image 1 is a black and white image, said image 1 either being obtained as a black and white image or as a colour image that is processed to be a black and white image.

16. A method according to any one of claims 12 to 14 in which said colour image is processed to be a black and white image by selecting at least one information channel (red, green or blue) of the digital image and creating therefrom the black and white image (image 1) in an electronic frame.

17. A method according to any one of claims 12 to 16 in which in step a) image 1 is subjected to a smoothing operation to create a smoothed image (image 1a) followed by a shade correction process using image 1a to produce an image (image 1b) corrected for shading differences, image 1b then being passed to step b).

18. A method according to any one of claims 12 to 17, in which erode and open operations are applied to the images to clean up the boundaries of the bubbles and to improve the differentiation of the spacing between the bubbles.

19. A method according to any one of claims 12 to 19 in which, prior to step c):

i) subjecting image 1 or image 1b to an adaptive segmentation process to produce a binary image;

ii) if necessary, inverting image 4 to show white lines and black blobs; and

iii) subjecting the images from steps i) and ii) to a Boolean “

SUBTRACT”

operation.

20. A method according to claim 19 in which the resultant image is subjected to thin, invert, erode and open operations.

21. A method of determining the height of foam generated from a liquid in a tube comprises subjecting a digital black and white image of the foam in the tube to the following electronic operations:

a) copying the digital image (image 1) into an electronic frame (image 2) and then clearing image 2 from this frame to create a new blank frame having the same pixel dimensions as the original digital image 1;

b) creating a rectangle in a graphics plane associated with the electronic frame and merging the graphics plane with the image plane of image 2 and specifying the rectangle is white or black and the remainder is black or white thereby creating a binary image (image 3) of a rectangle, the rectangle having dimensions longer than the anticipated length of the foam being measured and narrower than the width of the internal dimension of the tube;

c) subjecting the original digital image 1 to a segment process to generate a binary image (image 4);

d) subjecting image 3 and image 4 to a Boolean “

AND”

operation to create an image (image 5) representative of the foam height; and

e) measuring image 5 to determine the foam height.

22. A method according to claim 21 in which, in step b), the rectangle is white and the remainder is black.

23. Apparatus for assessing foam generation from a liquid comprising a tube open at one end for receiving liquid samples and in which foams can be generated, a gas diffuser means locatable within the tube and through which a gas flow through a sample located within the tube can be generated, a gas flow control means whereby gas flow through said diffuser means is controllable, an opto-electronic device located in use adjacent the tube, said opto-electronic device being capable of generating data-relating to foam in the tube, and control means for initiating action in response to input from the optoelectronic device.

24. Apparatus according to claim 23 in which the gas diffuser means is a metal sinter having a plurality of holes passing through it.

25. Apparatus according to claim 23 or claim 24 wherein the opto-electronic device is capable of detecting the top of foam being generated in the tube and, in response thereto, providing an output to the control means in response to which the control means is operable to terminate gas flow to the diffuser means and to store the time taken from initiation of the gas flow to termination of the gas flow.

26. Apparatus according to claim 23 or claim 24 wherein the opto-electronic device is capable of detecting the top of foam being generated in the tube and, in response thereto, providing an output to the control means in response to which the control means is operable to terminate gas flow to the diffuser means and to store that event, the control means also being operable to control gas flow for a predetermined period unless it receives input from the opto-electronic device within said period and, if said period expires, terminating gas flow and initiating relative movement between the tube and the opto-electronic device whereby inputs into the control means are generated from which the height of the foam generated is determinable.

27. Apparatus according to any one of claims 23 to 26 wherein the opto-electronic device is movable relative to the tube.

28. Apparatus according to any one of claims 23 to 27 wherein the opto-electronic device is operable to detect the air/foam and the foam/liquid interfaces, the difference between the positions of said interfaces being the height of the foam generated from the liquid in said period.

29. Apparatus according to any one of claims 23 to 28 wherein, the opto-electronic device is a photoelectric device whose beam in use is interruptible by the foam but not by air or the liquid.

30. Apparatus according to claim 23 or claim 24 wherein the opto-electronic device is capable of capturing an image of the foam from a location externally of the tube, the control means being operable to initiate relative movement of the tube and the optoelectronic device with respect to one another to position the opto-electronic device at a location relative to the tube at which location, in use, the image is captured.

31. Apparatus according to claim 30 comprising a second opto-electronic device operable to generate data from which the height of foam generated in the tube may be determined.

32. Apparatus according to claim 31 wherein the tube and the second opto-electronic device are mounted for relative movement with respect to one another

33. Apparatus according to claim 31 the second opto-electronic device is operable to detect the air/foam and the foam/liquid interfaces and provides inputs into the control means from which the height of the foam generated is determinable.

34. Apparatus according to any one of claims 23 to 28 wherein, the opto-electronic device is a photoelectric device whose beam in use is interruptible by the foam but not by air or the liquid.

35. Apparatus according to claim 31 wherein the second opto-electronic device is fixed relative to the tube position and is capable of capturing an image of the whole foam column that, in use, is generated in the tube and transmitting such an image to the control means, the control means being operable to analyse the image so received to provide a measurement of foam height.

36. Apparatus according to any one of claims 23 to 35 further comprising a workstation at which is located the opto-electronic device or devices and automated handling equipment for moving the tube relative to said workstation and for positioning the gas diffuser means in the tube, said control means being adapted to control said automated handling equipment to move the tube to and from the workstation, to move the tube and the opto-electronic device or devices relative to one another and to move the gas diffuser means into and out of the tube.

37. Apparatus according to claim 36 in which one or more tubes in which cleaning fluids for the gas diffuser means are locatable are provided at the workstation or at a separate, cleaning, workstation, said automated handling equipment being controllable by the control means to sequentially move the gas diffuser means between the first tube and the cleaning tube or tubes.

38. Apparatus for assessing foam generation from a liquid comprises a workstation at which is located an opto-electronic device capable of generating data relating to foam generated from liquid located in a tube, a gas diffuser means locatable within a tube into which a liquid sample can be located and through which a gas flow into such a sample can be generated, a gas flow control means whereby gas flow through said diffuser means is controllable, automated handling equipment for moving a tube relative to said workstation and for positioning the gas diffuser means in such a tube, and control means for initiating action in response to input from the opto-electronic device and being adapted to control said automated handling equipment to move a tube to and from the workstation and relative to the opto-electronic device whilst it is located at the workstation and to move the gas diffuser means into and out of a tube.

39. Apparatus according to claim 38 in which the control means and the automated handling means are capable of moving the optoelectronic devices relative to the workstation passed a plurality of locations at which sample tubes are locatable.

40. Apparatus for assessing foam generation from a liquid comprising at least one first workstation at which is located, in use, sample tubes and cleaning tubes, a second workstation at which is located sample dispensing means, a third workstation at which, in use, cleaning tubes are locatable, a fourth workstation having a parking location for receiving a gas diffuser means that can be placed within a sample and through which a gas flow can be generated and a gas flow control means whereby gas flow through said diffuser means is controllable, and a fifth workstation at which is located an opto-electronic device capable of generating data relating to foam generated from liquid located in a sample tube, said apparatus further comprising automated handling equipment and control means for initiating action in response to input from the opto-electronic device and being adapted to control said automated handling equipment, in use of the apparatus, to move cleaning tubes between the first and third workstations and to move sample tubes from the first workstation to the fourth workstation, to locate the gas diffuser means in the sample tube and to move the sample tube containing the gas diffuser means to the fifth workstation and to move the tube and the opto-electronic device relative to one another.