Method for determining the bubble point or the largest pore of membranes or of filter materials

• US 4,744,240 A
• Filed: 05/26/1987
• Issued: 05/17/1988
• Est. Priority Date: 05/27/1986
• Status: Expired due to Fees

• Current Assignee: Akzo Nobel N.V. (Nouryon BV)
• Original Assignee: Akzo Nobel N.V. (Nouryon BV)
• Inventors: Reichelt, Gert
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): WILLIAMS, HEZRON
• Application Number:
  US07/053,485
• Time in Patent Office: 357 Days
• Field of Search: 73/38, 73/64.3, 73/19
• US Class Current: 73/38
• CPC Class Codes: B01D 65/102 Detection of leaks in membranes
• CPC Class Codes: G01N 15/082 Investigating permeability by forcing a fluid through a sample
• CPC Class Codes: G01N 15/0826 and measuring fluid flow rate, i.e. permeation rate or pressure change
• CPC Class Codes: G01N 15/088 Investigating volume, surface area, size or distribution of pores; Porosimetry
• CPC Class Codes: G01N 2015/084 Testing filters

Abstract

When determining the bubble point or the largest pore of a membrane or of a filter material, the membrane or the filter material is placed in a container, with the membrane or the filter material thus dividing this container into two compartments. Then, the first compartment is filled with gas, and the second compartment and the pores of the membrane (or the filter material) are filled with a wetting liquid. The pressure in the gas compartment is raised at least until the gas displaces the liquid from the largest pore. The bubble point is defined by means of the gas-compartment pressure then prevailing, or the cross-sectional dimension of the largest pore can be calculated. According to the invention, the gas-compartment pressure corresponding to the bubble point is determined by measuring a sudden increase in the sound intensity in the liquid compartment. The measurement of the sound intensity is preferably carried out in the ultrasonic range.

Claims

1. A method for determining the bubble point or the largest pore of a membrane or filter material, comprising:

placing said membrane or filter material in a container in such a way as to divide the container into a first compartment and a second compartment;

filling the first compartment with a gas and filling the second compartment and pores of the membrane or filter material with a liquid which wets the membrane or filter material;

raising the gas pressure in the first compartment over time at least until a pressure in the first compartment is established at which the gas displaces the liquid from the largest pore of the membrane or filter material;

measuring sound intensity in the second compartment while raising said pressure; and

determining a pressure in said first compartment at which a sudden increase of the sound intensity can be detected.

2. The method according to claim 1, wherein the measurement of the sound intensity is conducted in an ultrasonic range.

3. The process according to claim 1, wherein the pores are evacuated by application of a reduced pressure before filling of the pores with the wetting liquid.