US2312910A - recovery apparatus - Google Patents

Description

March 2, 1943. H. Y. JENNINGS 2,312,910 RECOVERY APPARATUS Filed Oct-. 5. 1939 Joli/e02? 23 g '0 NVENTOR;

- the heating or vaporizing coils.

Patented Mar. 2, 1943 OFFICE RECOVERY APPARATUS Harley Y. Jennings, Clio, Mich, assignor to Cope-.

man Laboratories Comp poration of Michigan any, Flint, Mich, a cor- Application October 5, 1939, Serial No. 298,077

2 Claims. (01. 34-73) This invention relates to the recovery of solvents from substances or materials treated with a solution of a resinous substance in such solvents.

More particularly the invention relates to the recovery of halogenated hydrocarbon solvents, such for example as carbon tetrachloride, tetra chlorethylene and trichlorethylene. These solvents possess the common characteristics of a relatively low heat of vaporization and a specific,

gravity considerably higher than that of water. Their non-inflammability and the fa cility with which they may be condensed, without the use of absorption apparatus, make them particularly desirable for general use. 4

It has been found that the apparatus herein described permits the recovery of these solvents by direct condensation without any substantial admixture of air. The percentage of solvent recovered by my apparatus is relatively high and the simplicity of construction and ease of operation make it particularly desirable for use in connection with standard commercial apparatus, such for example as textile finishing apparatus.

Referring to the drawing for a detailed description of one embodiment of my apparatus;

Fig. 1 is a longitudinal section of a recovery apparatus embodying the features of invention,

Fig. 2 is a fragmentary section taken on the line 2--2 of Fig. l and showing a plan view of portions of the apparatus on an enlarged scale, and

Fig. 3 is a transverse section through the apparatus taken on the line 33 of Fig. l.

Broadly speaking, my apparatus comprises an elongated tank or chamber through which the treated material passes over a heating source such as steam coils, and a condensing device or coils disposed on either side of the treated material for condensing the vaporized solvent by the use of a suitable coolant such as water. The top side i or roof of the chamber is relatively low so that air is displaced and the chamber is substantially filled with solvent vapors which tend to flow in divergent directions from the center of the chamber toward the respective condensing coils disposed in wells on opposite sides of the vaporization chamber. The condensing wells are provided with sloping bottom walls so that the condensed solvent may be drained therefrom to v a suitable storage tank or tanks for re-use.

The entrance and exit ports for the treated material are located considerably higher than By this construction I take advantage of the relatively high weight of the solvent used sity of a tight seal at these ports.

Referring to the drawing. l0 designates th apparatus generally. A longitudinally extending chamber I I is disposed between entrance and exit tanks I2 and I3 respectively. A suitable source of heat such as steam coils I4 extends along the lower portion of chamber I I and provides a means for vaporizing the solvent from the treated material. I5 and I6 designate the inlet and outlet respectively for the steam pipes I4.

A port or slot I1 is provided in the upper wall of the entrance tank I2 for permitting entrance of the material to be treated, and a similar port or slot I8 is provided in the upper wall of exit tank I3 to permit withdrawal of the treated material from which the solvent has been removed. 'It should be noted that these ports or slots I1, I 8 are located at a considerable height above the level of the vaporizing chamber II and the steam coils I4. By this construction I take advantage of the relatively heavy weight of the halogenated solvent and its low specific heat to prevent escape ofthe solvent from the tanks I2 and I3: and it is therefore unnecessary to have a gas tight seal at the places of entrance and exit of the material as would be the case with a lighter and more volatile solvent.

It is preferable to provide balfles I9 depending from the roof 20 of the vaporizing chamber II toward the heating coils I4. The purpose of these bafiies is to break up longitudinal circulation through thechamber II and to retard or prevent the mixing of air with the solvent vapors.

A pair of condensing chambers 22 are disposed on opposite sides of the vaporization chamber II. These chambers are preferably tapered at their bottoms as indicated at 23, and the bottom of each condensing chamber slopes toward a valve or cook 24 from which the condensed solvent is discharged into a suitable storage tank in receptacle 25. Condensing coils 26 are disposed in the lower portion of each condensing chamber 22. These coils carry any suitable condensing medium, and for most solvents ordinary tap water is satisfactory.

Valve controlled vents 2| are provided at spaced intervals along the top wall 2'! of each condensing chamber 22. These vents, which may be provided with ordinary stop cocks, are opened when the system is started in operation and are left open until substantially all the air in the vaporizing chamber has been expelled, after which they are closed.

In the operation of my device, the material to be treated, such as cloth on a roll 28 is threaded through the apparatus as shown in Fig. 1 through the inlet chamber l2, the vaporizing chamber H and the outlet chamber Hi to a wind-up roll 29. Supporting rolls I20, and I30 are located in chambers l2 and I3 respectively. A motor 35 drives a belt 36 connected to wind-up roll 29. Inside the inlet chamber I2 is a suitable device such as a spray 30 for applying treatingmate rials, such as resins dissolved in volatile organic solvents to a surface of the fabric or cloth. As the treated material passes over the heating coils II, the solvent is vaporized and passes in the general direction indicated by the arrows in Fig. 3 into the two condensing chambers 22 where the solvent is condensed by the coils 26. When in operation the solvent vapors substantially fill thevaporizing chamber H and the condensing chambers 22, and as the system is substantially closed, the pressure inside the apparatus is slightly greater than that of the atmosphere so that there is no leakage of air into the system and the solvent vapors are liquefied by direct condensation. This arrangement provides a very eificient system of condensation, particularly when the solvents used have a high specific gravity, as do the chlorinated solvents which 1 preferably use.

The efiiciency of the system may be materially increased by the use of suitable insulation, such as non-metallic packing 3| between the hot and cold parts of the apparatus.

While I have shown a specific embodiment of the invention, it is apparent that other forms might be adopted, all coming within the scope of the appended claims.

I claim:

1. In a solvent recovery apparatus for recovery of chlorinated hydrocarbons from material which has been subjected thereto, entry and exit chambers spaced from each other, means for passing a continuous sheet of liquid treated material between said chambers, and a recovery apparatus tral vaporization chamber,

connecting and disposed substantially at the bottom of said chambers, said recovery apparatus comprising a relatively long and shallow vaporization chamber, heating means disposed in said vaporization chamber adjacent the lower wall thereof and a relatively short distance below the liquid treated material, recovery chambers at each side of said vaporization chamber and having portions disposed below said vaporization chamber but open thereto, cooling means in the lower portion of each of said recovery chambers, whereby a heavler-than-air vapor derived from the heating of said treated sheet material will flow by gravity to the lower portions of said recovery chambers and be condensed by said cooling means, and outlet means in the lower part of said recovery chambers for draining off the condensed liquid, and means on the upper portion of the recovery chambers for permitting the discharge of air from the apparatus when the apparatus is initially operated.

2. A solvent recovery apparatus comprising a central vaporization chamber, a heating means disposed in said central chamber, walls defining a pair of substantially closed end chambers connected to opposite ends of the central vaporization chamber, said end chambers comprising exit and entry chambers for the apparatus, some of the walls of each of said end chambers extending substantially above the vaporization chamber, means for causing a material to be passed horizontally through said vaporization chamber, a port disposed in a wall of each end chamber adiacent the top thereof, each of said ports being located at a level substantially above the censaid ports providing for the passage of material therethrough, condensing means associated with the vaporization chamber for condensing vaporized solvent, and means provided in the lower part of the condensing means for withdrawing condensed solvent from the apparatus.

HARLEY Y. JENNINGS.

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