MASS LOADING MONITOR

• US 20100107738A1
• Filed: 11/02/2009
• Published: 05/06/2010
• Est. Priority Date: 11/03/2008
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Lawrenz, Alan R., Foss, John F.
• Granted Patent: US 8,302,460 B2
• Time in Patent Office: Days
• US Class Current: 73/28.10
• CPC Class Codes: G01N 15/06 Investigating concentration of particle suspensions by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10
• CPC Class Codes: G01N 9/266 for determining gas density
• CPC Class Codes: G01N 9/36 Analysing materials by measuring the density or specific gravity, e.g. determining quantity of moisture methods of measurement in general G01N9/02 - G01N9/32

Abstract

The present invention provides a mass loading monitor for measuring in real time the particulate, i.e., powder, dust and the like, content of air inside an industrial or commercial processing facility and providing a warning signal indicating the existence of a potentially explosive atmosphere in the facility. In a first embodiment, the mass loading monitor comprises two parallel cylinders, one of which is charged with clean, ambient air and the other of which is charged with air from within the facility containing dust, powder or other particulate matter. A piston resides within each cylinder and the pistons are commonly accelerated for a short distance during which time the pressure at each piston face is measured. The time integrals of the pressures from each of the piston faces are evaluated over the period: from rest to the time of discharge from the open end of the cylinders. The ratio of these integrals defines the difference in the densities within the cylinders. In a second embodiment, a single piston and cylinder assembly is first calibrated with clean air and subsequently filled with particulate laden air and the time integrals of the pressures on the piston face are similarly evaluated.

Claims

1. An apparatus for measuring particulate concentration in air comprising, in combination,

an elongate cylinder having a piston disposed therein,

means for supplying particulate laden air to said cylinder,

means for translating said piston in said cylinder, and

means for sensing pressure in said cylinder proximate said piston during translation.

2. The apparatus of claim 1 further including a second piston disposed in a second cylinder disposed in parallel and having the same diameter as said elongate cylinder.

3. The apparatus of claim 2 wherein said means for translating is a pneumatic cylinder having a piston rod coupled to both of said pistons.

4. The apparatus of claim 2 wherein said means for translating is a single device having an output coupled to both of said pistons.

5. The apparatus of claim 1 wherein said means for translating is a rotating cam and a cam follower selectively engagable with said cam.

6. The apparatus of claim 1 wherein said means for supplying particulate laden air to said cylinder is a venture assembly positioned at an end of said cylinder.

7. The apparatus of claim 1 further including means for storing sensed pressure data from said means for sensing pressures.

8. The apparatus of claim 2 further including a pair of second pistons disposed in front of a respective one of said pistons and means coupled to said means for translating said pistons for translating said second pistons relative to said pistons.

9. The apparatus of claim 1 further including means for transmitting sensed pressure data from said means for sensing pressures to a location remote from said cylinders.

10. An apparatus for measuring particulate concentration in air comprising, in combination,

a first control assembly having a first cylinder and a first piston defining a face disposed therein,

a first air supply for providing reference air to said first cylinder,

a second measurement assembly having a second cylinder and a second piston defining a face disposed therein.

a second air supply for providing particulate laden air to said second cylinder,

drive means for translating said pistons in said cylinders,

pressure sensing means associated with each of said pistons for sensing pressures at said faces of said pistons during translation.

11. The apparatus of claim 10 further including a second piston disposed in front of each of said pistons and means coupled to said means for translating said pistons for translating said second pistons relative to said pistons.

12. The apparatus of claim 10 further including a plurality of ports in walls of each of said cylinders, a sliding collar for selectively closing and opening said ports and an actuator for translating said collar associated with each of said cylinders.

13. The apparatus of claim 12 further including control means for sequencing operation of said means for translating said pistons, said means for translating said second pistons and said actuators.

14. The apparatus of claim 10 wherein said cylinders are disposed in parallel and have the same internal diameter.

15. The apparatus of claim 10 further including means for storing and transmitting sensed pressure data from said means for sensing pressures.

16. An apparatus for measuring particulate concentration in air comprising, in combination,

an elongate cylinder defining a plurality of ports and having a piston disposed therein,

a first drive assembly for translating said piston across said ports to allow particulate laden air to enter said cylinder,

a second drive assembly for rapidly translating said piston in said cylinder, and

means for sensing pressure in said cylinder proximate said piston during rapid translation.

17. The apparatus of claim 16 wherein said first and second drive assemblies include rotating cams and an active cam follower having selectively movable cam engaging pins.

18. The apparatus of claim 17 further including a motor for driving said first drive assembly, said second drive assembly and a sequencer for controlling said active cam followers.

19. The apparatus of claim 18 further including a speed reduction assembly operably disposed between said motor and said second drive assembly.

20. The apparatus of claim 16 further including a jet ejector assembly selectively positionable at an end of said cylinder.