Particle monitoring system

• US 4,114,557 A
• Filed: 10/28/1976
• Issued: 09/19/1978
• Est. Priority Date: 05/14/1970
• Status: Expired due to Term

• Current Assignee: Robert J De Brey
• Original Assignee: Robert J De Brey
• Inventors: De Brey, Robert J.
• Primary Examiner(s): Goldstein, Herbert
• Application Number:
  US05/736,467
• Time in Patent Office: 691 Days
• Field of Search: 15/339, 73/170 R, 73/28, 73/194 B, 73/228, 73/432 PS, 116/67 R, 116/112, 116/117 R, 340/239 R
• US Class Current: 116/67.00R
• CPC Class Codes: A47L 9/19 Means for monitoring filtering operation
• CPC Class Codes: A47L 9/281 the amount or condition of incoming dirt or dust
• CPC Class Codes: A47L 9/2894 Details related to signal transmission in suction cleaners

Abstract

A particle monitoring apparatus having a particle sensing unit which receives mechanical signals caused by impaction of particles on a sensor and transforms the mechanical signals to an electrical signal related to the amount of particles moving with a fluid, as air. The output signal is used to produce readable information related to the movement of particles in the fluid.

Claims

1. A particle monitoring apparatus for sensing particles in a flowing fluid comprising:

first means having a first passage for carrying air and particles, second means having a second passage for carrying air and particles, said second passage being substantially parallel to and offset from the first passage, a housing connecting the first means with the second means, said housing having a chamber in communication with the first passage and second passage and a wall facing the chamber, said wall connecting the first means with the second means and having an angled portion located in general alignment with the longitudinal axis of the first passage, said chamber having a cross sectional area larger than the cross sectional area of either the first or second passage, a particle sensor mounted on said angled portion of said wall, said sensor located in alignment with the first passage so that the particles moving from the first passage are directed toward the sensor, said sensor operable to detect particles that strike the sensor and establish electrical signals related to the number of particles that strike the sensor, said sensor comprising a piezoelectric crystal having a surface exposed to the chamber upon which the particles impinge, said crystal being mounted on the angled portion of said wall and having a shape that conforms to the general shape of the inside of the wall whereby the crystal has a minimum extension into the chamber, an electronic circuit connected to the crystal to sense said electrical signals, and an output device operatively coupled to said circuit whereby said electrical signals are transformed to readable information related to the number of particles that strike the crystal.

2. The apparatus of claim 1 wherein:

the first means is an inlet tube and the second means is an outlet tube, said outlet tube being located in an offset relation with respect to the inlet tube, said housing connecting the adjacent ends of said tubes.

3. The apparatus of claim 1 including:

a mount for attaching the piezoelectric crystal to the wall.

4. The apparatus of claim 3 wherein:

said mount is a resilient member.

5. The apparatus of claim 1 wherein:

the first means, second means and housing comprise a one-piece tubular member.

6. A particle monitoring apparatus for sensing particles entrained in a flowing fluid comprising:

means having a chamber and an inlet passage and outlet passage open to the chamber for carrying fluid and particles, said inlet passage having a portion thereof substantially parallel to and offset from the outlet passage, said means having an angled wall forming a wall of the chamber facing the inlet passage and generally located in alignment with the longitudinal axis of the inlet passage, a particle sensor mounted on said angled wall in general alignment with the inlet passage for detecting particles that strike the sensor and establishing electrical signals related to the number of particles that strike the sensor, said sensor including sensor means having a surface exposed to the chamber and generally aligned with said inlet passage upon which the particles impinge to establish said electrical signals, said sensor means being mounted on the angled wall with the surface exposed to said chamber and generally aligned with said inlet passage and having a shape that conforms to the general shape of the inside of the wall whereby the sensor means has a minimum particle flow restricting extension into the passage, an electronic circuit connected to said sensor means having a surface to sense electrical signals established by the impaction of particles on the surface, and an output device operatively coupled to said circuit whereby said electrical signals are transformed into readable information related to the number of particles that strike the surface.

7. The apparatus of claim 6 wherein:

said chamber has a cross sectional area larger than the cross sectional area of either said inlet passage or outlet passage.

8. The apparatus of claim 6 wherein:

said sensor means having a surface includes a piezoelectric crystal.

9. The apparatus of claim 8 including:

a mount for attaching the piezoelectric crystal to the wall.

10. The apparatus of claim 9 wherein:

said mount is a resilient member.