Cleaning and liquid contact with solids – Processes – Using solid work treating agents
Patent
1993-08-11
1996-07-09
Straub, Gary P.
Cleaning and liquid contact with solids
Processes
Using solid work treating agents
134175, 570177, 570263, 588205, 588900, A62D 300, B09B 300, C07C 1738
Patent
active
055340776
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method and an apparatus for the disposal of foam material containing propellants and more particularly of foam materials such as polyurethane employed as an insulating material for refrigeration appliances in accordance with the preamble of claim 1 and, respectively, claim 14.
In the Federal Republic of Germany as many as 2 million refrigeration appliances are taken out of service annually. As is known such refrigeration appliances contain fluorinated hydrocarbons as a liquid circulating refrigerant, that is to say FHC, such propellant, more especially the FHC Frigen R11 also being employed as a foaming agent for forming the cells of polyurethane foam material (or PUR foam) and consequently being contained in the foam materials utilized for insulation.
Moreover there are many other types of appliances and apparatus which comprise propellant likely to damage and attack the ozone layer.
This is the reason that the disposal of such appliances constitutes a problem which is attracting more and more attention.
The refrigerant used in the refrigeration circuit may in such cases be directly discharged from the refrigerant circuit. The problem then remaining is the propellant still comprised in the synthetic resin foam.
In accordance with the German patent publication 4,004,336 C1 there has therefore been a proposal to break down such refrigeration appliances in a sealed chamber mechanically and then to abrasively blast out the fragments produced with the aid of granular abrasive blasting materials. In this case the intention is to cut up the sealed cells of the polyurethane foam material and destroy the cells walls. The abrasively blasted fragments are freed of polyurethane foam flocks or, respectively, flour and for recycled for abrasive blasting. The polyurethane flocks and the respective polyurethane flour are collected and disposed of as compacted briquettes. The entire contaminated air in the chamber is drawn off at a number of points are absorbed by activated carbon filters.
In accordance with a method described in German patent publication 3,929,666 Ai the foam materials containing fluorinated hydrocarbons are charged into a sealed chamber. The chamber is then pumped free of air and a pressing ram is driven into the chamber to compress the polyurethane foam with the result that the foam cells break down. The emerging propellants drawn off and collected.
In the case of the known method described in German patent publication 3,811,486 A1 there is a provision for placing foam material particles containing propellant and/or refrigerant more particularly in the form of FHC in a comminuting chamber, through which a fluid in the form of air passes. The emerging gaseous propellant is entrained in this fluid current. The fluid current is, after emerging from the comminuting chamber, fed to at least one cooling stage in order to condense out the propellant and/or refrigetant in such cooling stage.
In the case of the method previously described in the German patent publication 8,914,957 U1 there is also the feature that after the performance of a conventional shredding operation, as in the prior art method already described, the mixture of air, dust and fluorinated hydrocarbon is pumped off in order after cleaning to liquefy the propellant in a condensate collector.
Shredding as such possesses a number of disadvantages. In the shredded mixture there is, after degassing; as a rule still a substantial quantity of PUR foam and consequently of the fluorinated hydrocarbon Frigen R11. It is still possible for this propellant bound in the remaining foam to escape into the surroundings after removal of the foam material from the treatment chamber. In fact shredding is only able to be employed for recovering raw materials subject to certain conditions, from the mixture of materials coming from the shredder plant can only broken down into the individual components at great expense. In the case of synthetic resins this is frequently even impossible in some cases. Furthermore, shredding often requires
REFERENCES:
patent: 5175381 (1992-12-01), Hubers et al.
Lichtblau Josef
Wallner Heinrich
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