Method for inhibiting explosions

• US 4,378,851 A
• Filed: 09/08/1980
• Issued: 04/05/1983
• Est. Priority Date: 09/08/1980
• Status: Expired due to Term

• Current Assignee: Quad Environmental Technologies Corp INC.
• Original Assignee: Quad Environmental Technologies Corp INC.
• Inventors: deVries, Egbert
• Primary Examiner(s): Rolla, Joseph J.
• Assistant Examiner(s): Noland, Kenneth
• Application Number:
  US06/185,024
• Time in Patent Office: 939 Days
• Field of Search: 169/43, 169/45, 169/46, 169/47, 169/54, 169/64, 169/66, 239/290, 239/75, 261/118, 261/DIG. 15, 241/31, 241/38, 241/41, 241/16, 423/245
• US Class Current: 169/45
• CPC Class Codes: A62C 3/04 for dust or loosely-baled or loosely-piled materials, e.g. in silos, in chimneys flame traps A62C4/00
• CPC Class Codes: B02C 23/04 Safety devices in general F16P ; for rotary mills B02C13/31
• CPC Class Codes: B03B 9/06 specially adapted for refuse
• CPC Class Codes: B09B 5/00 Operations not covered by a single other subclass or by a single other group in this subclass
• CPC Class Codes: Y02W 30/52 Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly

Abstract

The frequency of explosive events in mills and other processing equipment is reduced and their severity lessened by introducing an aqueous microdroplet dispersion of controlled particle size range into the equipment under conditions such as to ensure survival of an adequate microdroplet population during transit through the equipment. Droplet diameter is limited to a size range of less than about 20 microns so as to avoid impingement stripping of the droplets from suspension and the relative humidity of an air stream passing through the equipment is adjusted to avoid droplet loss through evaporation.

Claims

1. A method for suppressing or attenuating explosions within processing equipment having an entrance and an exit in which flammable mixtures of air with gas, dust or vapor are at least occasionally produced which comprises introducing into said equipment a sufficient quantity of aqueous microdroplets having a diameter less than about 20 microns to provide a droplet concentration in the air throughout the equipment including at the equipment exit sufficient to quench an incipient gas, dust or vapor explosion and the droplet concentration in the air at the equipment exit is sufficient to provide a spacing between individual droplets of less than about 0.2 cm.

2. The method of claim 1 wherein said equipment is an impact mill.

3. The method of claim 2 wherein the air stream entering said mill is conditioned by humidification prior to introducing said aqueous microdroplets therein.

4. The method of claim 3, wherein a small amount of a water soluble oxidizing chemical is introduced into the processing equipment.

5. The method of claim 2 wherein municipal solid waste is shredded in said impact mill and wherein said aqueous microdroplets have a maximum diameter of less than about 10 microns.

6. A method for suppressing or attenuating explosions within processing equipment having an entrance and an exit in which flammable mixtures of air with gas, dust or vapor are at least occasionally produced which comprises introducing into said equipment a sufficient quantity of aqueous microdroplets having a diameter less than about 20 microns to provide a droplet concentration in the air throughout the equipment including at the equipment exit sufficient to quench an incipient gas, dust or vapor explosion and the droplet concentration is such that the spacing between individual micro droplets is such that the passages or pathways throughout the mass of said microdroplets are sufficiently narrow to prevent flame progagation in said flammable mixtures.

7. A method for maintaining the concentration of aqueous microdroplets in processing equipment, wherein flammable mixtures of air with dust, gas or vapor are at least occasionally produced, at a level sufficiently high so as to quench incipient explosions which comprises:

limiting the particle size of said aqueous microdroplets introduced into said equipment to a maximum diameter of about 20 microns,

wherein the concentration is such that spacing between the individual microdroplets is such that the passages or pathways throughout the mass of said microdroplets are sufficiently narrow to prevent flame propagation in said flammable mixtures, and

maintaining the relative humidity of air passing through said equipment at a sufficiently high level as to minimize evaporation of said droplets.