GB2226025A

GB2226025A - Cleaning solvent purification

Info

Publication number: GB2226025A
Application number: GB8829468A
Authority: GB
Inventors: David E Fowler
Original assignee: Quadrex Hps Inc
Current assignee: Quadrex Hps Inc
Priority date: 1988-12-16
Filing date: 1988-12-16
Publication date: 1990-06-20
Also published as: FR2641977A1; DE3901356A1; GB8829468D0

Description

p -- 1 - A -I- METHOD OF AND APPARATUS FOR PURIFYING CLEANING SOLVENTS

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention relates generally to a method of and apparatus for purifying cleaning solvents, and more specifically, to the decontamination of cleaning solvents contaminated with particulate matter, chemical agents, toxins and/or biological agents.

BRIEF DESCRIPTION OF THE PRIOR ART

There are varlous methods in the prior art which apparently teach the removal of contaminants from a cleaning solvent so that the solvent can be reused. Each of these methods is directed toward the removal of specific contaminants. An example of this is United States Patent No. 3, 923,541 which teaches a vapor degreasing system using a dual liquid solvent arrangement. The Healy vapor degreasing system is directed specifically to the removal of rosin or resinous acids from the object being cleaned. The primary solvent used in the vapor degreaser dissolves to rosin and drips to the bottom of the degreaser upon condensation. The dissolved ros in then comes in contact with an aqueous organic or inorganic bas6 residing in the bottom of the degreaser which serves to saponify the rosin. The, Healy vapor degreasing system is not directed to the removal of those chemical nerve and blister agents from cleaning solvents which may be encountered In chemical warfare and therefore, Healy does not

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offer or even suggest means for accomplishing such result. United States Patent No. 4,394,216 to McCord apparently teaches a vapor generating and recovery apparatus utilizing a cleaning solution containing water, an immiscible solvent and an emulsifying agent. The cleaning solution is apparently vaporized and then condensed in another chamber and returned to the cleaning chamber in separate streams of solvent and water. McCord does not teach or suggest a method for removing and neutralizing chemical nerve and blister agents from a cleaning solvent.

United States Patent No. 4,218,311 to Newrick is directed toward extraction processes for the production of copper, nickle or zinc. The extraction process uses an organic solvent or a liquid ion exchange material for extraction from a contaminated aqueous solution. Newrick does not, in any way, suggest or even relate to a method for removing chemical nerve and blister agent from a solvent.

United States Patent No. 4,337,121 to English, deals with the removal of oil from a metal surface as commonly encountered in the shaping and working of metal and the subsequent removal of the contaminant from the cleaning solution so that the cleaning solution can be reused. The English patent, as with many of the other patents cited herein, is directed toward the removal of a contaminant which is not, In any way, related to chemical nerve and blister agents.

IL t t 1 United States Patent No. 3,888,693 to Schevey apparently teaches a rather complicated method for removing liquid contaminants from solid surfaces and later purifying the cleaning solution for future use. The process involves the use of at least three (3) separate liquids. The second liquid should be substantially insoluble in the first liquid, while the third liquid should be miscible with the first liquid. When the contaminating first liquid is acidic or basic, a neutralizing agent may be incorporated into the system to neutralize the contaminant. Schevey is directed particularly to the removal of processing solutions in the manufacture of articles. Such contaminants may include ethanol, isopropenyl, aliphatic hydrocarbons or halogenated hydrocarbons and, therefore, bear no relationship to the chemical nerve and blister agents which are r,2moved from the solvent in the present invention.

As is illustrated by the prior art patents cited above, various cleaning and solvent purification systems have been proposed, each directed toward the removal of a specific contaminant or group of contaminants. Nothing in the prior art deals with those contaminants commonly referred to as chemical nerve agents and chemical blister agents which may be encountered in chemical warfare. Such nerve agents include tabun, sarin and samon. The chemical formulas for tabun, sairin, and soman are (CH NP(O) (C H 0) (CN) (CH) CHOI 3 2 2 5 3 2 YPO and (CH CCII(CH) OPF(O) CH respectively. Mustard 3 3 3 3 (dichlorodiethyl sulfide) and lewisite (beta-chlorovinyldi- 1 A 1 5 2-5 chloroarsine) are examples of the blister agents which may be encountered. Further, the process of the present invention serves to destroy and remove from the cleaning solvent toxins such as micotoxin commonly referred to as yellow rain. Such micotoxin may also be encountered in a chemical warfare situation. The process also serves to destroy various biological agents such as an thr ax, salmonella and botulinum which may be encountered in biological warfare.

We will describe a method of and apparatus for purifying a cleansing solvent used in decontaminating articles contaminated with chemical warfare nerve agents such as tabun, sarin, and soman.

We will describe method and apparatus which serves to remove solvent chemical warfare type blister agents and lewisite.

We will describe a method of and apparatus for deactivating and removing toxin contaminants such as micotoxin which is commonly referred to as yellow rain.

We will describe a method of and apparatus for deactivating and removing from the solvent biological agents such as anthrax, salmonella and botulinum.

a from a cleaning such as mustard 1 L We will also describe a method of and apparatus for removing radioactive particulates from a cleaning solvent so that the solvent can be reused for cleaning purposes.

We will describe a method of and apparatus for removing by liquidlliquid extraction chemical nerve agents and chemical blister agents from a cleaning solvent such that the cleaning solvent can be reused for cleaning purposes We will describe a method of and apparatus for oxidizing or otherwise chemically breaking down chemical nerve and blister agents dissolved in a cleaning solvent into nontoxic components.

Briefly stated, the foregoing and numerous other features, objects and advantages of the present invention will become readily apparent upon reading the detailed description, claims and drawings set forth hereinafter. These features, objects and advantages are accomplished by mixing the contaminated solvent with the neutralizing agent In order to perform liquid/ liquid extraction of the chemical contaminants dissolved in the solvent. The neutralizing agent is comprised of an aqueous solution of calcium hypochlorite or sodium hypochlorite available chlorine and sodium hydro xide or potassium hydroxide. The concentration of the calcium or sodium hypochlorite must be greater than 1.0% available chlorine and the concentration of sodium hydroxide or potassium hydroxide must be greater than 1.0 Normal.It is necessary to mix the is -6contaminated solvent with the neutralizing agent because the neutralizing agent isf nonmiscible With the solvent, such solvent being trichlorotrifluoroethane. Proper mixing assures contact between the neutralizing agent and the chemical contaminants dissolved in the solvent which allows complete liquid/liquid extraction of the chemical nerve and blister agents. The "neutralizing agent then serves to chemically attack the nerve and blister agents such that they are broken down into nontoxic components.

Mixing of the solvent with the neutralizing agent also assures contact between the neutralizing agent and any biological agents or chemical toxins which may be present in the cleaning solvent. Due to the extreme basic nature of the neutralizing agent, such contact by the neutralizing agent of any biological agents or chemical toxins present in the cleaning solvent renders such contaminants inert.

The solvent is then circulated through a filter for the removal of particulate matter which would include any radioactive particulates contained within the cleaning solvent. The solvent is then placed in a separator tank where any entrained neutralizing agent is separated from the solvent. Clean solvent is thus produced for reuse in cleaning operations.

It should be recognized that the method of purifying solvent of the present invention is easily adaptable for use with dry cleaning apparatus used for the decontamination of contaminated garments, tool and weapon decontamination units, vapor degreasers and the like.

A 1 1 5 1 1 1 BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a flow diagram of one embodiment of the process to remove chemical nerve and blister agents, toxins and biological agents from a cleaning solvent.

Fig. 2 1 a a f low diagram of another embodiment of the process to remove chemical nerve and blister agents, toxins and biological agents from a cleaning solvent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning first to Fig. 1 there is shown a flow diagram of the cleaning sol%ent purification process of the present invention. Contaminated solvent is pumped through conduit 10 into reactor 12. There is provided a neutralization tank 14 containing a neutralizing agent comprised of an aqueous solution of calcium hypochlorite or sodium hypochlorite and sodium hydroxide or potassium hydroxide.

The concentration of calcium or sodium hypochlorite must be greater than 1.0% and the concentration of sodium hydroxide or potassium hydroxide must be greater than 1.0 Normal. The neutralizing agent may be in liquid or pelletized form. It should be recognized that if the neutralizing agent is in pelletized form, an initial charge of water will also be required in the reactor 12.

Neutralizing agent flows from tank 14 through conduit.16 into reactor tank 12. The reactor tank 12 contains weir 18 which maintains a constant level within reactor tank 12, Pump 20 takes a dual suction from reactor tank 12 through conduits 22 and 24. Conduits 22 and 24 exit reactor tank 12 is -8at different elevations t 0 assure adequate mixing of the neutralizing agent with the contaminated solvent. This is necessary because the neutralizing agent is nonmiscible with the solvent and therefore has a tendancy to stratify with the neutralizing agent floati.ng on top of the contaminated solvent. Therefore, the liquid drawn off through conduit 22 is predominantly neutralizing agent while the liquid drawn off through conduit 24 is mostly solvent.

Pump 20 discharges through conduit 26 to which is attached heater 28. By elevating the temperature with heater 28 of the contaminated solvent and neutralizing agent contained within conduit 26, the liquid/liquid extraction reaction is enhanced. After passing through heater 28, there is disposed in the path of conduit 26, a static mixer 30. Static mixer 30 ensures contact between the neutralizing agent and the contaminated solvent wherein the chemical nerve agents and blister agents are removed from the solvent by means of liquid/liquid extraction and subsequently broken down into nontoxic components by the neutralizing agent. Flow is then through a particulate filter 32 for the removal of any particulates including ay radioactive or biological contaminants whic-h may be present. Any biological contaminants captured by filter 32 would already have been contacted by the neutra.lizing agent and rendered inactive and nontoxic by the hgh pH of the neutralizing agent.

A 1, t 1 5 Upo n exi ting f il t:er 3 2, f 1 ow i a thr ough condui t 3 4 back to reactor tank 12. There is thus formed a continuous circulation loop beginning with reactor tank 12 and returning to reactor tank 12, with weir 18 maintain a constant level within reactor tank 12.

It should be recognized that heater 28 and static mixer 30 are optional and that all that is required is adequate mixing within reactor tank 12 to assure contact between the contaminants in the solvent and the neutralizing agent. This could be accomplished via the closed circulation loop shown in Fig. I with pump 20 pumping through filter 32 and back to reactor tank 12 without heater 28 and static mixer 30 being present. The presence of heater 28 and static mixer 30 do, however, enhance both the reaction time and contact between the neutralizing agent and the contaminants contained in the 3olvent.

In an alternative embodiment, it should be appreciated that reactor tank 12 could be equipped with a heating element and/or an agitation type mixer to accomplish a like result in achieving a more rapid reaction and greater contact between the contaminants and the neutralizing agents in a shorter period of time. It should also be noted that mixing in tank 12 between the contaminants and neutralizing agents can also -be accomplished by using pump 20 to supply an eductor located:Ln tank 12 so that the contents of. tank 12 are thoroughly nixed by the pumping action. Also, if pump 20 is a centrifugal type pump and a heating element is placed within reactor 1 -10tank 12, then sufficient mixing should take place within pump 20 to allow the deletion of an agitation type mixer within the reactor tank 12, or, similarly, the deletion of static inline mixer 30 within conduit 26 depending upon the particular embodiment selected to practice the present invention.

Reactor tank 12 is divided into two portions by weir 18. Pump 36 takes auction from that portion of reactor tank 12 which receives the overflow over weir 18. Pump 36 is automaticaly activated. and deactivated by high and low level controls 38. The discharge of pump 36 is into conduit 40 upon which is disposed cooling coil 42. Conduit 40 empties into separator tank 44 in which the neutralizing agent is separated from the cleaning solvent, trichlorotrifluoroethane. Cooling coil 42 serves to reduce the temperature of the effluent from pump 36 to thereby enhance separation in separator tank 44. Again, it should be noted that the neutralizing agent is nonmiscible with the cleaning solvent and therefore will stratify within the separator tank, the neutralizing agent floating In a layer 46 above the cleaning solvent 48. Separator tank 44 is provided with a baffle 50 which extends downward from the top of separator tank 44 allowing a gap between the bottom of the baffle 50 and the bottom of the separator tank 44 for the flow of clean solvent around baffle 50. Attached to baffle 50 toward the bottom of baffle 50 is coalescer pad 52 which Is placed in such a manner that flow around baffle 50 must be through coalescer pad 52. Coalescer k r 7 i A i 1 25 1 i 1 i 1 t 11- pad 52 serves to trap on its surface any moisture or neutralizing agent entrained in the trichlorotrifluoroethane such that the flow around baffle 50 and out discharge port 54 is clean solvent free of contaminants, neutralizing agents and water. As the neutralizing agent collects on coalescer pad 52 larger bubbles will form, break loose from the surface of the coalescer pad 52, and float to the top of separator tank 44 and become part of layer 46. Coalescer pad 52 is fabricated by wrapping polyester Crepe de Chine fabric about fiberglass insulation board.

Layer 46 exits separator tank 52 through port 56 and flows through conduit 58 by gravity back to reactor tank 12 thereby supplying reactor tank 12 with reusable neutralizing agent. In such manner, the need for make-up neutralizing agent is limited.

In an alternative embodiment, cooling coil 42 may be disposed within separator tank 44 instead of about conduit 40. Placing the cooling coil 42 within the separator tank 44 would accomplish the same end result of enhancing separation and would have the additional benefit of being more energy ef f icient.

Fig. 2 depicts an alternative embodiment of the present invention which negates the need for a reactor tank. Contaminated solvent enters static mixer 60 via conduit 62 from an external pump.. Simultaneously, neutralizing agent is conducted via gravity from neutralizing agent tank 64 through con- duit 66 into static mixer 60. Effluent from the static mixer 60 flows through conduit 68. There is optionally installed about conduit-68 a heater 70. The purpose of heater 70 is to raise the temperature of the mixture of contaminated solvent and neutralizing agent to thereby enhance the liquidlliquid extraction reaction. Branching off conduit 68 is conduit 72 which returns to inline static mixer 60 thereby creating a closed circulation loop. Disposed in series along conduit 68 are flow controller 74, micron particle filter 76 and cooler 78. Upon exiting cooler 78, conduit 68 empties into separator tank 80. Cooler 78 is optional and serves the purpose of reducing the temperature of the combined cleaning solvent and neutralizing agent to thereby aid the separation of such constituents within the separator tank 80. Disposed within separator tank 80 and extending downward from the top thereof is baffle 82. Attached to baf fle 82 is coalescer pad 84. Because the neutralizing agent is nonmiscible with trichlorotrifluoroethane and has a lower specific gravity than trichlorotrifluoroethane, stratification takes place in separator tank 80 with the neutralizing agent floating in a layer on top of the cleaning solvent. Flow of cleaning solvent within separator tank 80 Is through coalescer pad 84 and around baffle 82. Clean solvent exits separator tank 80 via conduit 86. Any entrained moisture or neutralizing agent attempting to migrate through the separator tank 80 with the cleaning solvent is captured by the coalescer pad 84. As large enough bubbles 1 Z i of water or neutralizing agent collect on the coalescer pad 84, they will break loose f rom the coalescer pad 84 and float up to become part of neutralizing agent laye r 88.

Neutralizing agent 88 returns to the s t a t i c mixer 60 via conduit 90. - In the embodiments discussed herein, -s-e.pa.ratton 1& accomplished gravimetrically. Separation may also be accomplished by other means including distillation and centrifugal separation.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed with reference to other features and -sub combinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from- the scope thereof it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

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Claims

WHAT IS CLAIMED IS;

1. k method of rendering nontoxic chemical nerve agents and/or chemical blister agents dissolved in a cleaning solvent and/or toxins and/or biological agents suspended in a cleaning solvent comprising; -.1 1 mixing the contaminatedA cleaning solvent with a nonmiscible, highly basic neutralizing agent thereby chemically breaking down the chemical nerve and/or blister agents dissolved in the sol,%ent into nontoxic components and deactivating the toxins and/or biological agents suspended in the solvent.

2. A method of removing and rendering nontoxic chemical nerve agents and/or chemical blister agents dissolved in a cleaning solvent and toxin and/or biological agents suspended in the cleaning solvent from the cleaning solvent comprising the steps of:

a. mixing the cleaning solvent having chemical nerve and/or chemical blister agents dissolved therein and/or having toxins and/or biological agents suspended therein with a nonmiscible, highly basis neutralizing agent; b. separating the solvent from said nonmiscible, highly basic neutralizing agent.

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3 6 7 9 1 2 3 1 2 3 4 5 6 7 3 4 i 1 1 3. A method of! removing chemical nerve agents and chemical blister agents from a cleaning solvent comprising the steps of:

as mixing the contaminated solvent with a nonmiscible neutralizing agent to effect liquid/liquid extraction of the chemical nerve and blister agents; b. separating the neutralizing agent from the solvent thereby achieving a cleaning solvent free of chemical nerve and blister agents suitable for safe reuse in cleaning operations.

4. A method for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited In claim 3 further comprising the step of:

heating the mixed contaminated solvent and neutralizing agent to enhance the liquidlliquid extraction reaction.

5. A method for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited In claim 4 further comprising the step of:

cooling the mixture of neutralizing agent and solvent as to a liquidlliquid extraction of the chemical nerve and blister agents has been effected to thereby enhance separatio-n of the neutralizing agent from the cleaning solvent.

6. A method for removing chemical nerve agents and chemIcal blister agents from a cleaning solvent as recited in claim 5, wherein:

said cleaning solvent is trichlorotrifluoroethane.

1.

3 4 1 2 3 4 5 6 1 2 3 4 5 6

7 8 9 1 2 3 4 5 6 7 7. A method for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claims 2 or 6 wherein..

said neutralizing agent is a mixture of an aqueous solution of concentrated bleach and caustic.

8. A method for removing chemical nerve agents and chemical blister agents from a cleaning solvent as-recited in claim 7 further comprising the step of:

coalescing any neutralizing agent entrained in said cleaning solvent o'n a coalescer pad to insure that separation is complete. -

9. A method for removing chemical nerve agents and chemicwl blister agents from a cleaning solvent as recited in claims 2 or 3 wherein:

said neutralizing agent is a minimum one percent (1.0%) solution of calcium hypochlorite and water containing at least 1.0 N hydroxide obtained by dissolving one member of the following group in said calcium hypochlorite solution:

(a) sodium hydroxide; (b) potassium hydroxide.

10. A method for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claims 2 or 3 wherein:

said neutralizing agent is a minimum o ne percent (1.0%) solution of sodium hypochlorite and water containing at least 1.0 hydroxide obtained by dissolving one member of the following group in said sodium hypochlorite solution:

i 1 8 9 1 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 (a) sodium hydrox ide; (b) potassium hydroxide.

11. A method for cleansing a cleaning solvent contaminated with chemical nerve agents, chemical blister agents, toxins, pesticides and/or biological agents and deactivating each such contaminant comprising:

(a) mixing the contaminated solvent with a nonmisible neutralizing agent to perform liquid/liquid extraction of the dissolved contaminants and to render inert the toxins and biological agents present in the solvent, said neutralizing agent thereafter chemically breaking down the extracted chemical nerve and blister agents into nontoxic components; (b) separating the neutralizing agent from the solvent thereby achieving a cleaning solvent free of chemical nerve and blister agents suitable for safe reuse in cleaning operations.

12. A method for cleansing a cleaning solvent contaminated with chemical nerve agents, chemical blister agents, toxins, pesticides and/or biological agents and deactivating each such contaminant comprising:

(a) mixing the contaminated solvent with a nonmisible neutralizing agent to thereby cause said neutralizing agent to contact and render inert any toxins or biological agents.present in the solvent; M extracting the chemical nerve and chemical bliater agents from the solvent with the neutralizing agent by liquid/liquid extraction; 2 3 14 is L6 L7 is 19 1 2 3 4 5 6 7 a 9 10 11 '12 13 14 15 (c) chemically Attacking the extracted chemical nerve and blister agents with the neutralizing agent to breakdown such agents into nontoxic components; (d) filtering the intermixed solvent and neutralizing agent to remove the particulate contaminants; (e) separating the neutralizing agent from the solvent thereby yielding a contaminant free solvent suitable for safe reuse'in cleaning operations.

13. In combination with a vapor degreaser, a method for cleansing the solvent used in said vapor degreaser comprising:

(a) mixing the contaminated solvent with a nonmiscible neutralizing agent to perform liquid/liquid extraction of the dissolved contaminants and to render inert the toxins and biological agents present in the solvent, said neutralizing agent thereafter chemically breaking down the extracted chemical nerve and blister agents into nontoxic components; (b) filtering the intermixed contaminated solvent and neutralizing agent to remove any particulate contaminants suspended therein; (C) separating the neutralizing agent from the solvent thereby achieving a cleaning solvent free of chemical nerve and blister agents suitable for safe reuse in cleaning operations.

1 4 ' 21 2 3 4 5 6 7 8 9 11 12 13 14 15 16 1 4 6 7 8 19 11 14. In combination with a dry cleaning apparatus, a method for cleansing the solvent used in said dry cleaning apparatus comprising:

(a) mixing the contaminated solvent with a nonmiscible neutralizing agent to perform liquid/liquid extraction of the dissolved contaminants and to render inert the toxins and biological agents present in the solvent, said neutralizing agent thereafter. chemically breaking down the extracted chemical nerve and blister agents into nontoxic components; (b) filtering the intermixed contaminated solvent and neutralizing agent to remove any particulate contaminants suspended therein; (c) separating the neutralizing agent from the solvent thereby achieving a cleaning solvent free of chemical nerve and blister agents suitable for safe reuse in cleaning operations.

15. In combination with a high pressure apt ay tool decontamination unit, a method for cleansing the solvent used in said high pressure spray tool decontamination unit comprising:

(a) mixing the contaminated solvent with a nonmiscible neutralizing agent to thereby cause said neutralizing agent to contact and render inert any toxins or biological agents present in the'solvent; (h) extracting the chemical nerve and chemical blister agents from the solvent with the neutralizing agent by liquidiliquid extraction; k 12 13 14 is 16 17 18 19 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 (C) chemically attacking the extracted chemical nerve and blister agents with the neturalizing agent to breakdown such agents into nontoxic components; (d) filtering the intermixed solvent and neutralizing agent to remove the particulate contaminants; (e) separating the neutralizing agent from the solvent thereby yielding a contaminant free solvent suitable for safe reuse in cleaning operations.

16. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent comprising:

(a) means for mixing a contaminated cleaning solvent with a neutralizing agent so that said neutralizing agent contacts any chemical nerve and blister agent contaminants present in said solvent thereby rendering said contaminants nontoxic, said neutralizing agent being nonmiscible and nonreactive with said solvent; (b) a separator tank for separating said neutralizing agent from said solvent; (C) means for conducting said solvent and said neutralizing agent from said mixing means to said separator tank.

17. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 16, further comprising; means for circulating said neutralizing agent from said aeparator tank back to s.aid mixing means.

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18. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 16, further comprising:

(a) means for heating said neutralizing agent and said solvent during mixing by said mixing means; (b) means for cooling said neutralizing agent and said solvent prior to separating said neutralizing agent and said solvent in said separator tank.

19. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 18, further comprising:

(a) means for collecting contaminant free solvent from said solvent tank; (b) a coalescer pad within said separator tank preventing carryover of entrained neutralizing agent with said solvent to said collecting means.

20. An apparatus for removing chemical nerve agents and chemical blister agents from a_cleaning solvent as recited in claim 19, wherein:

said neutralizing agent is a minimum 1.0% solution of calcium hypochlorite and water containing at least a 1.0 Normal hydroxide obtained by dissolving one member of the following group In said calcium hypochlorite solution:

(a) sodiura hydroxide; (b) potaasiura hydroxide.

7 B 9 1 2 3 4 1 2 3 4 5 6 7

21. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 19, wherein:

said neutralizing agent is a minimum 1.0% solution of sodium hypochlorite and water containing at least 1.0 Normal hydroxide obtained by dissolving one member of the following group in said sodium hypochlorite solution:

(a) sodium hydroxide; (b) potassium hydroxide.

22. An appara%us for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 19, wherein:

said cleaning solvent As trichlorotrifluoroethane.

23. An apparatus for removing chemical nerve agents and chemical blister agents from a cleaning solvent as recited in claim 22, further comprising:

a filter for the removal of particulate contaminants such as toxins and biological agents suspended in said trichlorotrifluoroethane, said neutralizing agent having rendered any toxin and biological agent contaminants nontoxic on contact.

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24. A method as claimed in claim 1, substantially as hereinbefore described.

25. A apparatus as claimed in claim 16 substantially as hereinbefore described with reference to the accompanying drawings.

is Published 1990 atThe Patent Office, State House, W71 High Holborn. London WCIR4TP- Further copies maybe obtained from The Patent Office Sales Branch, St Mary Cray, Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Kent. Con. 1'87