JPS62181873A - Recovery and purifying system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Description: TECHNICAL FIELD The present invention relates to a method and apparatus for blast cleaning the surfaces of workpieces to remove dirt, corrosion scale, and the like. More particularly, the present invention relates to recovering and cleaning propellant media for reuse.

■In recent years, agricultural products have been used for spray cleaning of sensitive processed products.
For example, lightweight polymeric propellants are replacing walnut shells, apricot pits, and the like.

This polymer-based propellant material not only has more consistent cutting properties, but is also inert to degradation due to environmental factors.

Polymeric media are relatively expensive and generally must be recovered for reuse. However, if the workpiece to be cleaned contains critical surface tolerances and the integrity of the substrate cannot be compromised, the cleanliness of the abrasive material must be precisely controlled.

Such recovery for reuse is not difficult when performing jet cleaning operations on relatively small articles and workpieces that can be jetted within the containment device. However, if the workpiece to be cleaned has large dimensions, e.g. an aircraft,
The propellant medium must first be collected at the work site, after which this medium must be cleaned and circulated.

After collecting the propellant media from the work site, contaminants such as paint chips, corrosion particles, and dirt must be separated from the polymeric media. Contaminants include large and fine materials that weigh approximately the same as the propellant. Furthermore, there are also fine powders and dirt whose weight is lighter than the propellant.

It is an object of the present invention to provide a reusable lightweight propellant medium, generally a polymeric medium, used as a gas-entrained abrasive to remove dirt, corrosion scale and the like from the surfaces of workpieces. An object of the present invention is to provide a system and method for collection and cleaning.

Methods and apparatus for recovering lightweight media from a work site involve, among other things, re-entraining contaminated abrasive material within a gas stream. The entrained contaminated abrasive media is sent to a separator and
The separator separates the heavier portions of contaminants and abrasive from the gas stream by impinging the gas stream on a target. The target reverses the gas flow and absorbs sufficient momentum of the heavier contaminants and abrasive material such that these relatively heavy materials fall continuously downward from the target while the lighter, finer materials fall within the gas flow. remains taken away.

Light, fine particulate contaminants and dust that remain suspended in the gas stream are removed from the separator by providing sufficient swirl and turbulence to the gas stream to blow the light contaminants away from the interior of the separator and from the continuously falling contaminated media. be blown away from The falling contaminated abrasive material is collected at the base of the separator and then re-entrained into the gas stream for a series of air washes similar to the first one.

In a preferred system, the separator discharges the heavier portions of the abrasive media and contaminants onto a screen system for further cleaning. Because the screen removes particles that are larger than the polymeric abrasive media, the heavier portion of the fines can pass through the screen system and be discarded, while receiving an equivalent portion of particles within the size range of the average propellant. The receiving section undergoes subsequent air cleaning and cleaning, and is later dropped into the hopper for reuse.

A system for recovering and cleaning polymeric jetting media for reuse includes a first suction system for re-entraining used contaminated abrasive material from the jetting work site into the gas stream. The entrained media is directed into a closed top separation tank designed to separate the light titanium powder portion of the contaminants from the abrasive media material and heavier contaminants. The tank includes a bottom drain for discharging the received material for further cleaning or to a storage hopper for reuse.

The closed top of the separator includes a first closed-ended cylinder having a smaller diameter than the tank and opening at the bottom into the tank, the closed end receiving a gas stream entrained with contaminated abrasive propellant material. It has become a target for The target cylinder reverses the impulse flow so that the abrasive and heavier contaminants fall to the bottom discharge of the tank while lighter fines, contaminants, and dust remain suspended within the gas stream. The top of the separation tank includes a second closed-ended cylinder of smaller diameter than the tank, the cylinder opening at the bottom into the interior of the tank and discharging the fines-contaminated gas stream exiting the interior of the separator. It has a side wall tangential discharge section for. A second suction system separates the air stream through a second closed-end cylinder to swirl the heavier abrasives and contaminants that fall continuously to the bottom of the tank and to blow lighter fines from the media and interior of the separator. Aspirate the tank of the device.

The system includes a series of screens for removing contaminants from the propellant medium by size. The first screen removes excess contaminants larger than 30 mesh.

Fines smaller than 80 mesh are passed through to waste. The material retained on the 80 mesh screen is essentially a cleaned, lightweight polymeric propellant. This media can then be sent for reuse or directed to a polish separator similar to the first air wash separator. The resulting 95-97% pure polymer blasting media is suitable for reuse.

(2) Best Mode for Dealing with Problems Referring to FIGS. 1 and 2, the system of the present invention is shown in detail in these figures. The workpiece in the illustrated example is an aircraft 10 that undergoes a jet cleaning operation to remove paint from the fuselage surface.

Nozzle 11 directs a controlled volume of a relatively soft polymeric jet cleaning medium 12 onto the surface of the aircraft. Spent propellant media and contaminated debris, such as dirt and paint chips, fall to the ground around the aircraft. The suction pump 13 enables the operator using the suction line 14 to re-entrain the used and contaminated propellant medium. The discharge from the pump 13 is directed to a first air cleaning separation tank 15. A discharge line 16 discharges entrained abrasive particles and contaminants into a closed-ended cylinder 17 whose bottom is open into the interior of the separation tank 15. The closed end cylinder 17 is
The direction of the gas flow in which the contaminated polishing media is entrained is reversed so that the jetting media and heavier contaminants 18 are transferred to the hopper collection zone 19 of the separation tank 15.
let it fall inside. Lighter parts of the contaminants, such as dust and light paint chips, remain suspended in the separation zone 20 of the tank in the free space above the collected material 18.

These light contaminants are sucked out of the tank through a second closed-ended cylinder 21, also shown in plan view in FIG. The second closed-ended cylinder 21 includes a side wall tangential discharge 22 which imparts a swirling motion to the gas in the separation zone 20 and prevents fines from settling anywhere within the separator. The falling receiver blows out the material to help and further remove fines from the tank and the falling medium. The second vacuum pump 23 has a tangential discharge section 22
Separation tank 15 is sucked through.

The contaminated injection medium 18 is transferred to the base 1 of the separation tank 15.
9 as a deposit. A discharge gate 24 meters the material into an entrainment system 25 and the re-entrained contaminated propellant is passed through a magnetic separator 26 to remove iron-containing contaminants.
is passed through and then directed into the second separation tank 27,
This tank 27 has the same shape and function as the first separation tank 15. The contaminated propellant medium, which has already had much of its fines removed, settles into the base of the separation tank 27 for passage through the transfer gate 28 into the cleaning system.

A first screen 29, typically 30 mesh, removes excess contaminants from the contaminated propellant media.

A second screen 30, typically 80 mesh, retains the propellant medium and allows heavy fines to pass into the waste bin 31. The fairly clean propellant medium falls into the re-entrainment system 32 which finishes the medium and sends it to the air washing purifier 3.
3, which is similar in design and function to the first separation system 15.

The cleaned injection medium is sent into the feed hopper 35 via the feed gate 34. The hopper 35 supplies the injection medium to the injection nozzle 11 .

At this point of reuse, the propellant medium contains only 3-5% contaminants.

During operation, the propellant medium is aspirated at the work site and is generated at approximately 85% per minute.
Separation unit 15 at a speed of 3 cm (2800 ft)
injected into the body. The distance from the injection pipe 16 to the top of the palm of the target cylinder 17 is such that the combination of gas flow velocity and the properties of the injected material ensures that the injected material is distributed substantially uniformly from the entrained gas to the collection zone 19 in the form of a curtain. Selected to fall.

Polyplus™, an amino-based thermosetting resin manufactured by Ni Nis Plastics and Chemical Corporation of Putnam, Conn., USA, is preferred as the polymeric propellant medium. This propellant material is 0.93-0.96 g/cn! (-58 to 60 pounds per cubic feed) and a diameter of approximately 50 mm at a speed of approximately 853 cm (2800 feet per minute)
．． 8 cm (20 inches) is discharged into the first closed cylinder. The separation tank of such a system has a diameter of 152.4 cm.

In this preferred system, the second suction pump 23 pumps approximately 13 to 15 inches of Hg into the separation tank.
Approximately 853 cm (2800 feet per minute) under pressure
Generates a slower fines-contaminated effluent gas stream.

When using Polyplus propellant, the screen system for removing heavy oversized fines should be 30 to 8
It is designed to collect a particle size range of 0 mesh.

In preferred operation, the entrained, contaminated propellant is injected into the first closed-ended cylinder at a rate such that the abrasive media material does not impinge on the top of the closed-ended cylinder. The purpose of this is to cause the propellant to lose momentum under the influence of gravity and internal gas resistance so that it falls in a uniform curtain and does not clump together, so that the falling material is free from dust and light contaminants from the falling material. It can receive a swirling flow of gas that blows things away. This effluent gas is velocity limited so that the polymeric propellant medium does not escape with the fines. However, the velocity must be sufficient so that dust does not settle or accumulate in the separator.

Although embodiments of features of the invention have been described for purposes of illustration, it will be understood from the foregoing description that various changes may be made without departing from the spirit and scope of the invention. Therefore, the present invention is not limited by the description other than the claims.

4. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a schematic diagram showing the collection and cleaning system of the present invention, and FIG. 2 is a separation system that includes first and second closed-ended cylinders and generates an air flow by suctioning fine contaminants. 1 is a schematic diagram showing a top view of a tank;

12...Polymer-based spray cleaning medium 13...Suction pump 15...First air cleaning separation tank 17...Closed end cylinder 19...Popper collection zone 21...Second closed end cylinder 22... ...Tangential discharge part 23...2nd suction pump drawing 8 (no change in content), L FIG. 2 Procedural amendment (formality) 1. Indication of case 1985 Patent Application No. 260521
No. 2, Title of the invention Collection and purification system 3
, Relationship with the person making the amendment Applicant name Cover Incorporated 4, Agent

Claims (11)

[Claims] (1) In recovery and cleaning systems for the reuse of contaminated lightweight materials used as gas-entraining abrasives to remove contaminants, such as dirt, corrosion scale and the like, from the surfaces of workpieces; a first suction system for re-entraining used contaminated abrasive material from the field into the conveying gas stream; and a top closed separation tank including a bottom portion and an upper portion for collecting and discharging said abrasive material. the upper portion includes a first closed-ended cylinder containing a target surface directly impinged by the gas stream containing contaminated abrasive and a second closed-ended cylinder of smaller diameter than the tank; The cylinder includes a substantially unrestricted bottom discharge from which impinged abrasive, contaminants and carrier gas are discharged, the abrasive and heavier contaminants being directed downwardly into the bottom portion of said separation tank. The falling, lightweight contaminants remain suspended in the carrier gas flowing into the upper part of the tank, and the second cylinder is open at the bottom into the upper part of the tank, and a sidewall tangential outlet for discharging said gas stream contaminated with light contaminants from an upper part of the interior of said second cylinder, the system sucking into said separation tank through a tangential outlet of said second cylinder; further comprising a second suction system for discharging the entire upper portion of the separator by actuation of a tangential discharge of a second cylinder so that the effluent gas blows light contaminants away from heavier abrasive material that continuously falls to the bottom of the tank. a collection and cleaning system which imparts a swirling motion to the gas and discharges the abrasive material free of light contaminants from a bottom discharge of the tank. (2) the contaminated gas stream is injected substantially vertically into the impingement target at such a rate that all material of the same weight as clean abrasive material continuously falls from the impingement target to the bottom of the separator; A collection and cleaning device according to claim 1. Claim 1 further comprising: (3) a dust collector for receiving the fines-contaminated gas stream exiting the tangential discharge of the second cylinder and for removing fines from the gas stream.
Recovery and purification systems as described in Section 1. 4. The collection and cleaning system of claim 1, including a screen for receiving heavier abrasive material discharged from the bottom discharge of the tank and for removing contaminated debris larger than the abrasive material. 5. The recovery and cleaning system of claim 4, wherein the screen removes material larger than 30 mesh from the contaminated abrasive material. (6) The screen is capable of retaining abrasive material larger than 80 mesh for reuse for abrasive cleaning and passing through finer debris and heavy fines for disposal as claimed in claim 5. system. 7. The recovery and cleaning system of claim 4, wherein a magnetic separator is included in front of the screen to remove contaminated debris containing iron. (8) said light contaminant separation system includes a plurality of such separators in series, the bottom discharge of each separator except the final separator recycling said partially cleaned material into the gas stream; connected to a suction system for entrainment, the gas flow being directed to the first target cylinder of the next tank, said final tank having a bottom discharge for discharging the clean abrasive material into a hopper for reuse for abrasive cleaning. A collection and cleaning system according to claim 1. (9) A method of recovery and cleaning for reuse of lightweight abrasive material used as a gas-entrained jet cleaning abrasive, comprising re-entraining said contaminated abrasive material in the gas stream and disposing of the lightweight abrasive and Reversing the gas flow so that the heavier, larger sized portions of the contaminant continue to fall from the target while the lighter portions of the contaminant continue to be entrained within the gas stream, separating lightweight contaminants from the heavier portions of the contaminated entrained abrasive material by impinging the gas stream on a target that absorbs significant momentum; and separating the lightweight contaminants suspended in the gas from the continuously falling heavier material. collecting the continuously falling abrasive material contaminated with heavier and larger sized contaminants, and separating contaminant particles larger than the abrasive material from particles smaller than the abrasive material. A recovery and cleaning method comprising: screening the collected partially cleaned abrasive and collecting said screened substantially clean lightweight abrasive for reuse. 10. The method of claim 9, wherein the collected abrasive material is screened to separate particles larger and smaller than the abrasive material. 11. The method of claim 9, wherein the abrasive material is a polymeric material.