Photoelectric bubble detector apparatus and method

• US 4,779,448 A
• Filed: 01/28/1986
• Issued: 10/25/1988
• Est. Priority Date: 01/28/1986
• Status: Expired due to Term

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Gogins, Mark A.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): CAIN, DAVID C
• Application Number:
  US06/823,306
• Time in Patent Office: 1,001 Days
• Field of Search: 73/38, 73/293, 73/290, 250/221.1, 250/221.2, 250/573, 250/574, 364/550
• US Class Current: 73/38
• CPC Class Codes: G01N 15/088 Investigating volume, surface area, size or distribution of pores; Porosimetry

Abstract

A photoelectric buffle detector apparatus (20) including a container (22) containing a liquid (24) having a top surface with a top side and an under side. A light emitting source (60) is positioned for emitting light toward the top surface (42) of the liquid (24). A light detecting source (70) positioned for detecting light emitted from the light emitting source (60) and reflected from the top surface (42) of the liquid (24). The light detecting source (70) outputs a signal indicating the presence of a wave pattern at the top surface (42) of the liquid (24) caused by gas bubbles rising to the top surface (42) of the liquid (24).

Claims

1. An apparatus for determining the size of pores in a filter media, comprising:

(a) container means for containing a liquid, the liquid having a top surface;

(b) light emitting means for emitting light directed toward the top surface of the liquid;

(c) disturbance means for causing bubbles of gas to rise to the top surface of the liquid from a location below the top surface of the liquid such that the top surface of the liquid is disturbed thereby causing a wave pattern at the top surface of the liquid having an associated frequency, the disturbance means including gas means for delivery of gas under pressure into the liquid of the container means at a location below the top surface of the liquid, the gas means including means for providing a path for the flow of gas into the liquid, the gas means further including means for selectively varying the gas pressure;

(d) fixture means for mounting the filter media in the path of the gas, the filter media prohibiting the flow of the gas into the liquid over a range of gas pressures such that the wave pattern is not present, the filter media having a first side facing the liquid and a second side facing the gas under pressure;

(e) light detecting means for detection of light emitted from the light emitting means and reflected from the top surface of the liquid, the light detecting means including output means for output of a signal indicating the presence of the wave pattern due to the gas under pressure flowing through the filter media and causing the gas bubbles to rise to the top surface of the liquid; and

(f) frequency detection means associated with the light detecting means for receiving the signal output from the light detecting means and for detection of a predetermined signal frequency, the frequency detection means including means for output of a signal indicating detection of the predetermined signal frequency.

3. An apparatus in accordance with claim 1, wherein the frequency detection means includes filter means for filtering out all frequencies other than the predetermined frequency.

2. An apparatus for determining the size of pores in a filter media, comprising:

(a) container means for containing a liquid, the liquid having a top surface;

(b) light emitting means for emitting light directed toward the top surface of the liquid;

(c) disturbance means for causing bubbles of gas to rise to the top surface of the liquid from a location below the top surface of the liquid such that the top surface of the liquid is disturbed thereby causing a wave pattern at the top surface of the liquid having an associated frequency, the disturbance means including gas means for delivery of gas under pressure into the liquid of the container means at a location below the top surface of the liquid, the gas means including means for providing a path for the flow of gas into the liquid, the gas means further including means for selectively varying the gas pressure;

(d) fixture means for mounting the filter media in the path of the gas, the filter media prohibiting the flow of the gas into the liquid over a range of gas pressures such that the wave pattern is not present, the filter media having a first side facing the liquid and a second side facing the gas under pressure;

(e) light detecting means for detection of light emitted from the light emitting means and reflected from the top surface of the liquid, the light detecting means including output means for output of a signal indicating the presence of the wave pattern due to the gas under pressure flowing through the filter media and causing the gas bubbles to rise to the top surface of the liquid, the signal output having a frequency representative of the frequency of the wave pattern; and

(f) means for determining the frequency of the signal output from the light detecting means.

4. An apparatus for detecting the size of the pores in a porous filter media, comprising:

(a) reservoir means for containing a liquid, the liquid having a top surface with a top side and an under side;

(b) light emitting means for emitting light directed toward the top surface of the liquid;

(c) a source of gas under pressure, including an outlet means for providing gas under pressure to the liquid in the reservoir;

(d) fixture means for retaining a filter media in association with the reservoir means so as to obstruct the output means with the filter media, a side of the filter media facing the liquid and a side of the filter media facing the gas under pressure;

(e) means associated with the gas under pressure for selectively varying the pressure applied against the side of the filter media by the gas, whereby at some range of gas pressure bubbles are formed on the liquid side of the filter media and rise to the top surface of the liquid thereby creating a wave disturbance resulting in a wave pattern at the top surface of the liquid having an associated frequency;

(f) light detecting means for detecting variations in the amount of light emitted from the light emitting means and subsequently reflected from the top surface of the liquid, the light detecting means including means for output of a signal having a frequency representative of the frequency of the wave pattern;

(g) filter means operatively interconnected to the detecting means for filtering out all but a predetermined frequency, the filter means including means for transmitting a signal indicating detectiion of the predetermined frequency;

(h) pressure differential means for sensing the pressure differential between the gas under pressure and the gas pressure in the container above the top surface of the liquid; and

(i) means operatively interconnected to the filter means for receiving the signal output by the filter means and operatively interconnected to the pressure differential means for receiving a signal from the pressure differential indicative of the pressure differential.

5. An apparatus in accordance with claim 4, wherein the means operatively interconnected to the filter means and the pressure differential means includes computer means for storing information represented by the signals received from the filter means and the pressure differential means and for performing analysis on the information.

6. A method for determining the porosity of a porous filter media, comprising:

(a) positioning a filter media in association with a reservoir containing liquid such that the filter media is positioned over an outlet from a source of gas under pressure, one side of the filter media facing the liquid and one side facing the gas under pressure;

(b) selectively varying the amount of pressure exerted by the gas against the filter across a range of gas pressures such that at one end of the range of gas pressure bubbles are formed on a liquid side of the filter media, thereby causing a wave pattern at the top surface of the liquid having an associated frequency;

(c) directing a light source toward the top surface of the liquid;

(d) detecting the amount of light reflected from the top surface of the liquid; and

(e) detecting the presence of the wave pattern by by detecting the variation in light reflected from the top surface of the liquid.

7. A method in accordance with claim 6 wherein the step of determining the amount of light reflected includes the step of outputting a signal representative of the frequency of the wave pattern, amplifying the signal and selectively filtering out all but a predetermined frequency, and output of a second signal indicative of the presence of the predetermined wave pattern frequency.

8. A method in accordance with claim 7 including monitoring the second signal and the amount of pressure exerted against the filter media and recording the gas pressure differential between the pressure exerted by the gas under pressure and the air in the reservoir above the top surface of the liquid when the wave pattern is initially detected.