US1228225A

US1228225A - Apparatus for recovering solvents.

Info

Publication number: US1228225A
Application number: US72601612A
Authority: US
Inventors: James Lynah
Original assignee: DuPont Powder Coatings USA Inc
Current assignee: DuPont Powder Coatings USA Inc
Priority date: 1912-10-16
Filing date: 1912-10-16
Publication date: 1917-05-29
Anticipated expiration: 1934-05-29

Description

' LYNAHY.

APPARATUS FOR RECOVERING SOLVENTS.

APPLICATION FILED OCT. l5, 19l2.

. LNQQQ OOOOOOOOODUOQOOOO000009000000000 i STATES BAT-ENT OFFICE.

um Luni, or New Yonx, salomon 'ro E. r. u rom' amours :com or wrmrmeron; nmwama, Aeonron'rron or maw misser. .seminaires ron ucovmzmc sonvmrrs.

Patenten May 29, 1917.

Application mea ommis, 1912. serial no. mmc.

Tacll whom it may concem:

Be it' known that 1,; JAMES LYNAH, of

Newburgh, in the county of Orange and .in

the State of New York, have invented a certain new and Tuseful Improvement in Apparatus for Recoverin Solvents, and do hereby declare that the allowing 1s a full, clear, and exact idescription thereof.

.My invention relates particularly to a method .andmeans' for recovering solventsY usedin coatin compositions, although' it may be adapte to u se in any other connec tion"where it is desired to recover f's'olvents; My invention is particularly applicable to the recovery'of .solventsfrom .coatin of paper or textile fabrics containing india rubber, pyroxylin, 011s, paints or'varmshes, and employing volatile solvents suchas `benzol, alcohol, ether, acetoneor turpentme:I

The object ofmy inventionz 1s to provide a process fand. apparatus for' carrymg'out Vthe same, iin which avery' large percentage ofthe solvent utilizedmay be recovered. in the drying operation; 'infwhich 'the drylng operation is eectedr'with the. greatest de-4 grec of-rapidityyandwin. which the danger of'serious explosions 1s m1n1m1zed. A urtherobject ofimy 'invention 'is to'enable the coating operationsto be carried out with the smallest possible amountof laborand with 4the greatest degree ofuniformlty of result. Further objects of my inventlon are to provide 'agnapparatus ofthe kind described, 'w'hich is constructed with "a closed chamber Vin which the coating is applied-to the surface 'operated upon in a closed, vapor-ti'glfit` chamber; to effectively spread the materials in 'said chamberf; 'to'mainta1n the surface operated upo'n` taut 'so as to avold wrinkles; toprevent the escapeofjyapors 'at the point where the'iiexible matemal for receiving 'the coating enters leaves the apparatus; and to provide 'a cover which 1s loosely supported upon the top of the apparatus to avoiddama'ge in case of an explosion. y L

As ilh'lstrative forms of apparatus which may be use'd for carry-mg 'out my process, I have 'shown twoA different forms iqf appae ratas in the 'accompanying ldrawmgs, 1n which# AFi re 1 represents a'side elevatlon of one Vforni of apparatus which maybe used for carrying but my processythe apparatus In'Fig. 1, I show a continuous strip of 4 paper or 'textile fabric 1 which is conducted over a' 'supporting roller 2, Y and thence around a spreading roller?,4 which may-.be constructed irl-any desired-manner to move the `tw'o' 'free Aends;- of the cloth laterally to remove' the wrinkles from the same. From thisp'oint-'the-web of material to be coated passesl through a slot into a chamber 4 having'at itsfront, immediately above the web '1, adool' 5.' Within the chamber 4 the web i-ssupported upon a pair of-,idler rollers 6 and between these rollers a knife 7 is' provided for spreading'orut upon-the surface ofthe goods in a uniform .layer a coating of any ldesired composition containinga volatilesolvent, such' as pyroxyln dissolved inamixture 'of solvents, for example, benzol,-a1'eoho1,' etc., -ledr into the chamber in front of'the knife by means of a feed pipe 8. lThe chamber 4 is so'constructed that all of the joints are-as tight as-possibley `to prevent the escape of the 'vaporized' solvent. From the chamber 4 the web, together 'with the solvent vapors which accumulate in the chamber 4, pass into a long, fiat metal-lined evaporatng` chamber-9, having al-plu'rality of idler rollers 10'to support the traveling web. immediately above the traveling web there is a series of radiator coils 11 which is adapted '.tofreceive a current of hot water or i'steam "at the end farthest removed from the pointf-of entry of the web to be coated and adapted to discharge the same at 'the othervend of the-chamber. 'By this meansl the coated web will begradually same at the end from which the travelingl web is discharged, by means of a pipe 1d, and being discharged 'om the same at the other end by means of a pipe 15. The mixed air and evaporated solvent which are conducted' from` the evaporating chamber through the pipe 15 are led into a condenser 16 formed with a circuitous pamageway l? by the presence of aplurality of opposltely directed baiiie plates 18. A cooling coil 19 adapted to be fed with cold water or other coolin agent, is situated in the passageway 1%. llhe solvent which is condensed 1n the condenserv 16 is conducted away through a discharge `pipe 20 to any suitable receptacle. From the condenser 16 the air and any residual, uncondensed vapor are led b meanso a pipe 2l to a rotary fan 22 whi again returns the same to the evaporating chamber through a reheater 23 containing heating coils 23a, andthe pi e 14, which is connected to the reheater. leaving the .evaporating chamber, the coated web drawn through a pair of felt strips 24 by vmeans of a tension roller 25 over which the web is conducted, and from this point the web passes over an idler roller 26 to the surface of a horizontal belt conveyor 27, where the coating is allowed to harden'before the web is `finally wound into rolls. The presence of the felt strips 24 e'ectually prevents any vapors from being dragged out of the evaporating chamber by the traveling web.

In Fig. 2, I have shown a type of apparatus which is constructed exactly the same as that shown in Fig. 1,except that between the fan 22 and the reheater 23, there located a trap' 28 to receive any solvent which is condensed between the fan and the reheater, this trap 8 being connected by a pipe 29 with the discharge pipey 20,. and near the bottom of the trap 28 there is located an upwardly directed vent pipe 30 to admit airy and allow any accumulated solvent to be discharged from the trap when desired through the branch 29 ofthe pipe 30.

In oarryingout' my process, the traveling web of paper or textile fabric is fed into a coating chamber in which it is provided with a uniform coating of the desired composition containing solvent. chamber is so arranged that the escape of any of the solvent vapors is prevented as far as pos,- sble. This is brought about by the fact that the coating composition is lcd into the chamber by means of a pipe, and the use of the spreader obviates the necessity of frequent access to the chamber to remove wrinkles. The vapors which accumulate in the chamber 4 are ultimately dragged into the evaporating chamber 9 through the traveling` web. l, whence they are withdrawn and condensed. As the traveling web i passes from this chamber it is received by the evaporating chamber which is arranged with the heating and drying coils above the' same toA avoid any drippings which might be enplosive in nature, from falling upon the coils om the' c oated web. The heating coils heat the traveling web principally by radiantheat,the heat being applied in this manner directly to the surface to be dried. This chamber is,rurthermore,' so arranged that the danger of explosion is minimized as the size of the chamber is made as small as possible to reduce the amount of solvent vapor contained therein, and as the cover is made so that it may be readily elevated in case of an explosion to relieve the pressure within the evaporating chamber. 'lhe presence of this particular type of cover also enables the heating devices on the interior, which are located above the surface of the co-ated web to be more readily accessible. The coated web rapidly dried in the evaporating chamber owing to the fact that the coils 11 radiate directly against the surfaceto be dried, and do not have to pass through the lower, uncoated side of the web., Furthermore, the rapid circulation of the air through the evaporating chamber enables the evaporation and drying to be effected as rapidly as is consistent with the production of a uniform smooth surface. At the same time, the` solvent which is taken up by the circulating current of air is quickly condensed in the condenserl, and is led away to any convenientcondenser where it may berecovered and used againinpreparing the coatingcomposition. The air and uncondensed vapors which pass through the condenser are again used by being passed through the reheater and into the evaporating chamber, theloss of any vuncondensed solvent vapors being thus entirely obviated. It sometimes happens that a small percentage of the uncondensed vapor becomes condensed and accumulates between the' fan and the reheater prior to the rentry of the current of air into the evaporating chamber, and if desired, the process may be operated with an apparatus such as that shown in Fig 2 in order to collect the solvent thus condensed between the 'fan and the' reheater, and the solvent condensed `in this manner may be conducted to the discharge lill@ pipe which leads from the condenser. The l that many changes may be made therein Without departing from the fundamental principles thereof.

I claim:

1. In a device of the character' described, an evaporating chamber', means for supporting a coated web in the same, a Vaporftight cover loosely supported over the saine and an air pipe connected to said cover.

2. In a device of the character described, an evaporatiner chamber, means for supportingI a coated web in the same, and a vaportight cover loosely supported over the same in a castor oil seal.

3. In a device of the character described, a feedingr chamber for a coating,r material, an evapo'rating chamber, means for supporting;I a coated web in the same, and a vapor-tight cover loosely supported over the feeding and evaporating chambers.

4. In a device of the character described,

a feeding chamber for a coating material, an v evaporatingr chamber, means for supporting as coated web in the same, and a vapor-tight cover loosely supported over the feeding and evaporating chambers in a liquid seal.

5. In a device of the character described, a feeding chamber for a coating material, an evaporating chamber, means for support ing' a coated web in the Same, and a vapor` tight cover. loosely supported over the feeding: and evaporating,r chambers located at the outer edge of the cover, and alsobetween the feeding chamber and the evaporating chamber.

In testimony that I claim the foregoing I have hereunto set my hand.

JAMES LYNAII.

Witnesses:

W. R. Umm,- It. B. I'IEYWARD.