US2310680A - Solvent saver - Google Patents

Description

C. F. DINLEY SOLVENT SAVER Filed May 28, 1940 2 Sheets-Sheet l 1 N V EN TQR: Clarence if DLnZe 1 7 B y W W A TTORNE Y5,

atented Feb. 9, 1943 SOLVENT SA Clarence F. Dinley, Detroit, Micln, assignor, by mesne assignments, to Detroit Rex Products Company, Detroit, lmch, a corporation of Michigan Application May 28, 1940, Serial No. 337,574

8 Claims.

My invention relates to the recovery of volatile solvents from clothes or textile materials that have been treated with such solvents, or from any article or material that absorbs, or adsorbs, or retains the solvent, as because of an interstitious or capillary structure, or for any otherreason. The invention is particularly useful for recovering dry-cleaning solvents such as carbon tetrachloride, trichlorethylene, or perchlorethylone, whose vapors are generally uninflammable, or any other volatile grease-removing solvents. It also permits of freeing clothes or fabrics of solvent odor remaining after solvent in them has been recovered as far as practicable. I have hereinafter explained the invention with particular reference to the dry-cleaning of clothes or the like.

In dry-cleaning clothes with volatile solvents, the clothes are agitated in a bath of the solvent to remove grease and dirt, and are then rapidly spun or centrifuged to expel as much as possible of the solvent. While the greater part of the solvent used is gotten out of the clothes and recovered in this manner, a substantial amount still remains; and it is therefore a common practice to hang the clothesln a place where a good air circulation is maintained, until they are free of all apparent odor of the solvent. In this way, the entire amount of solvent left in the clothes after centrifuging is lost, amounting, ordinarily, to some 10 to 20 lbs. of solvent per 100 pounds of woolen goods treated, and to some 20 to 45 lbs. of solvent per 100 pounds of cotton goods, according to the duration and speed, etc., of the centrifuging.

It is this solvent remaining in the clothes after the dry-cleaning operation that I aim to recover, by means of an apparatus which I have devised for the purpose. In suitable forms, such as here shown and described, my invention permits of recovering as much as some 95% of the solvent remaining in the clothes when treated in my apparatus. The apparatus can be made simple,

convenient, rapid, and economicalin operation,

and very efiicient in recovery of solvent, as well as rugged in construction and comparatively inexpensive to build. Other features and advantages of the invention will appear from the following description of a species and form of embodiment, and from the drawings. All the features and combinations shown and described are of my invention, so far as novel.

In the drawings, Fig. 1 is a front view of an apparatus conveniently embodying my invention, a large part of the front wall of the apparatus being broken away and removed, and some of the internal parts being shown in vertical section; Fig; 2 is a vertical sectional view from the left of Fig. 1, taken substantially as indicated by the line and arrows 11-11 in Fig. 1,

some parts in front of the section line IIII being also shown; and Fig. 3 is a fragmentary sectional view on a. larger scale than Figs. 1 and 2, taken substantially as indicated by the line and arrow III-III in Fig. 2.

As shown in Figs. 1, 2 and 3, the apparatus comprises a closed treating chamber In, or cylindrical form, in which the goods or material treated are traversed by a gaseous absorbent medium,

preferably air. To assure more thorough permeation of the goods by the air, they are preferably agitated or tumbled, for which purpose there is a rotary foraminous-walled container in the form of a cylindrical drum ll, revolving coaxially within the chamber [0. about a horizontal axis formed by a shaft 12 attached to the rear drum wall I3 and mounted in bearings It, It on an upright pedestal frame or column structure I5. As here shown, the drum II is of sheet metal, and its cylindrical wall is rendered foraminous by a multitude of evenly-spaced fine holes l6, and is provided with a series of inward-extending, evenly spaced, longitudinal baflies [1, while its rear end -l3 has bracing indicated at 88. The rear drum wall I 3 is closed; but the front of the drum II is open in correspondence to a door ill in the front wall of the chamber to, through which goods or work to be treated can conveniently be introduced and withdrawn. Preferably, the front chamber wall forms part of the front wall of a casing 2| which encloses the treating chamber ill, the pedestal i5, and the associated parts hereinafter mentioned. As shown, there is a base 22 on which the pedestal I5 is mounted, and around which the lower end of the casing 2i engages. Also, the front casing wall 20 has an opening with a removable closure 22a (which includes the door I 9), large enough to pass the drum II on occasion.

As shown in Fig. 2, the front end of the revolving drum H has an inward-extending partial wall or flange 23 whose rolled or beaded edge 24 defines its opening corresponding to the door l9, and the front wall portion 22a has an axially extending flange 25, formed by an angle bar welded on. The door I9 is shown dished inward to a depth suficient to bring its inner surface flush with that of the drum wall 23, and is marginally flanged to seat externally against the wall portion 22a. As shown in Fig. l, the door I9 is hinged to the front wall portion 22a at 26, to swing and open outward horizontally, about a vertical axis, and is provided with a pivoted securing-latch 21 that coacts with a catch 28 on the front wall portion 22a. In the center of the door I9 may be mounted a thermometer or temperature indicator 29, exposed and responsive to the temperature in the interior of the drum II, to show the temperature condition in the midst of the goods in the drum.

For circulating or passing air through the treating chamber ID and the goods in the revolving drum N, there is.a rotary blower or fan 30 directly below the chamber I8, mounted on the frame structure |5.. The axial intake conduit 3| of this fan 30 extends forward and upward in the form of a 90 elbow, and is connected through the lower wall of the chamber l0. In the bottom of the chamber I0, accommodated in a depression 32 of its lower wall, there is a lint filter 33 (of any suitable or usual air-filtering fabric) resting on attached marginal supporting strips 34 and readily removable through a separate door opening in the front wall 20. This door opening has a door or cover 35 hinged to the front wall 20 at 38, and provided with a handle and securing catch 3T, for normally holding it closed. The air-delivery conduit 38 of the fan 30 extends to one side (to the left) beneath the chamber III and upward ona slope beneath the latter to and beyond the vertical plane of the left hand chamber wall, where it changes or connects into an enlarged, flat. rectangular air trunk 40, which extends upward beside the chamber l and back (to the right) horizontally over this chamber, where it bends and opens downward at 4| through the top of the chamber by way of a slotlike opening which is substantially co-extensive in length with said chamber.

The solvent-laden air drawn by the fan 30 from the chamber In and delivered through the conduit 38, 4|) is chilled by means of a (sectional) condenser 42 mounted or interposed in this conduit in its upright trunk portion 40, just above the lateral connection of the conduit 38 thereinto, thus condensing the solvent vapor in the air to liquid. A sump 43 for collecting the condensed solvent drip from the condenser 42 may be provided in the closed lower end of the trunk 40, below the lateral connection of the conduit 38 thereinto, with a valved draw-oil connection 44. As shown in Fig. 2, the condensate draw-ofl pipe 44 has a depression 44a. which forms a liquid seal to prevent the entrance of air when the valve is open during operation of the machine. To increase the vapor tension or partial pressure of the solvent and the recovery thereof from the goods, provision is made for heating the aircirculated by the fan 30 through the conduit 38, 40, by means of a (sectional) heater 45 mounted or interposed in the conduit 40 close to its downward connection 4| into the chamber I0, between the latter and the condenser 42.

As shown in Fig. 1, the conduit or trunk 40 has an air-intake opening 50 formed in its elbow or bend 4| just above the chamber In, which is controlled by a swinging damper pivoted at 52. In advance of the condensate sump 43, the conduit 38 is provided with a vent branch or connection 53 extending downward and rearward and opening out through the rear wall of the casing 2| at 54. As here shown, controlling butterfly dampers 55 and 56 are provided in the conduits 38 and 53.

For driving the .fan 30 and the drum N, there is shown an (electric) motor 50 mounted on the pedestal 5 directly to the rear of the fan, and having one end of its shaft 8| directly connected to the fan rotor (not shown). The other end of the motor shaft 8| is shown connected to the drum shaft l2 through a belt connection 62, a speed reducer 53, and a belt connection 84.

As shown in Figs. 1 and 2, the condenser 42 and the heater 45 may be of fluid-heat-exchange type, each comprising two serially connected sections or units A, B. Each unit A, B comprises a serpentine tube of serially connected lengths 58 extending back and forth through a large number of rectangular metal fin plates 61. For a drum l of 36 in. diameter that is 24 in. deep in the axial direction and revolves at about 30 to 40 R. P. M., each heat exchange unit may consist of copper tubing of in. external diameter bent into a serpentine of eight 21 in. lengths, and the fin plates 61 may be 4 in. by 5 in. and so spaced that there are nine of them per in. of the tube lengths 56. The units A, B are arranged completely across the air trunk or conduit 40, to force the air to pass through them. In practice, the condenser 42 and the heater 45 may be just alike, with a total of 10.4 sq. ft. of tube surface each, and 106.8 sq. ft. of fin surface.

If desired, any two or more of the valves or dampers 5|, 55, 56 may be interconnected for concurrent or unified operation. For this purpose, the pa allel shafts 52, 68, 69 of the dampers 5|, 55, B are here shown provided with cranks 12, I3, and a crank 15 is shown fulcrumed on a pivot shaft 15 parallel with the damper shafts, in a bracket 11 attached to the wall of the chamber l0. As here shown, the cranks I5 and 12 are in the nature of bell-cranks. The crank 15 is connected by link-rods 8|, 82 to the cranks 1| and 12, and the latter is connected by a link rod 83 to the crank 13. A helical tension spring 84 is connected between one of the arms of the crank 15 and a fixed anchorage bracket 85 on the wall of chamber ID, in such relation to the shaft axis 15 that in the movement of shifting the dampers open and shut or viceversa the spring 84 passes dead-center: in other words, the spring normally holds all the dampers 5|, 55, 55 atone or the other extreme of their movement. As shown, the upper end of this spring 84 is connected to the pivot 86 that connects the link-rod 8| -to the crank 1|. For operating the interconnected dampers, one of the damper or pivot shafts may conveniently be utilized: 1. e., as shown, the shaft 88 is extended out through the front of easing 2| and is provided with an operating handle 81.

The apparatus may be operated as follows:

Condensing water and steam of suitable temperature and pressure being supplied to the condenser 42 and to the heater 45, a batch of some 20 lbs. of dry clothing that has been cleaned may be placed in the drum H, the door l8 may be closed, and the fan 30 and the drum may be rotated at suitable speeds-the dampers 5|, 55, 55 being in the positions shown in Fig. 1. The air is circulated by the fan 30 in a closed circuit through the heater 45, the goods in the treating chamber H), the lint filter 33, the fan 30, and the condenser 42. Issuing from the heater 45, the air warms up the goods and -vapo1izes solvent in them, to an amount approaching saturation at the temperature of the air. Passing through the filter 33 (which removes all lint picked up by the air from the goods) and through the condenser 42, the air is chilled by. the condenser,,and the solvent vapor therein is condensed, running down and dripping off into the sump 43. Thus cooled and relatively free of solvent, the air is reheated in the heater 45and so on indefinitely.

Operation of the machine in this mannermay continue until the cool air leaving the condenser 42 is just saturated with solvent vapor, which may be determined by noticing when condensate ceases to come from the draw-oil connection 44, or from a rise in the reading of the temperature indicator 29, and will rarely require more than 10 min. or less. As soon as this maximum recovery of solvent has been reached, the damper 5i may be swung to the left to open the outside air intake 50 and close the upper end of the conduit 40, and the dampers 55 and 56 may be turned 90 from their positions in Fig. 1 to shut oil the lower end of the conduit 38 from the fan 30 and to open the outside air vent 53, while the fan 30 and the drum l I continue in operation as before. Under these conditions, unheated outside air will be blown through the chamber i and the clothing or material therein, removing all perceptible traces of solvent odor, which will rarely require more than a minute. At the same time, air circulation through the conduit 38, 40, due to a chimney eflect of the heater 45 (or, in reverse, of the cooler 42) will be prevented by the dampers i, 55, each of which is effective for this purpose; and thus reevaporation and loss of condensate on the condenser cooling surfaces will be prevented. 'I'hereupon the motor 60 and the fan 30 and drum I I may be stopped and the door i9 may be opened, and the clothes or material may be removed from the apparatus, when theywill be found completely free of all odor.

Returning the dampers 5|, 55, 56 to their positions in Fig. 1 restores the apparatus toconditlon for treating another batch of articles or material. 7

About 90 gal. of condensing water per hour may be passed through the serially connected units A, B of the condenser 42, entering at a temperature of about 37 F. and leaving at about 50 F. in winter or entering at about 74 F. and leaving at about 80 F. in summer. The heater 65 may be supplied with dry steam at a pressure of about 5 to lbs. per sp. in. (gage) The fan 30 may be of such capacity and so operated as to give an air flow in the fan circuit of about 500 cu. ft. per min. Under these operating conditions, there may be a super-atmospheric air pressure corresponding to +1 in. of water in the fan delivery duct 38, ahead of the condenser 42, and to +0.35 in. of water in the duct 40, between the condenser 42 and the heater 45, while in the fan intake there may be a partialvacuum corresponding to 0.2 in. of water below atmospheric. The temperature of the air at 4!, where it enter the treating chamber 10, may be about 215 F. in winter or about 225 vF. in summer, while the temperature in the midst of the goods at the center of the drum ll may be about 140 F., more or less, and in the duct 40 above the condenser 42 the temperature of the air may be about 55 F. in winter and 83 F. in summer. Under conditions within the ranges here indicated, a solvent recovery of about 95% may be had. Quite surprisingly, the temperature of the condensing water (within these ranges) does not very materially affect the percentage of recovery.

It is quite unnecessary for the temperature in the center of the drum II to approach the boiling point of the solvent: on the contrary, a recovery substantially as indicated may be had for' any of the following solvents:

/ Boiling point, F.

Carbon tetrachloride 1'70 Ethylene dichloride 182 Trichlorethy 188 Perchlorethylene 250 However, the temperature at the center of the drum ll should never be excessive? e. g a temperature below 130 F. will not harm-any textile fabric, while a temperature above 150 F. is likely to cause shrinkage, especially in the case of woolens. Temperatures between 130 and 150 F. may

' or may not prove harmful, according to the character of the goods and other circumstances. The thermometer 29 helps the operator to avoid injurious over-heating of the goods.

Some of the features of my apparatus which are of importance for eiiicient and satisfactory operation may be briefly noticed.

It is important to have the heater 45 very close to the treating chamber III, as shown, so that the temperature in the chamber may be kept as high as possible with a minimum consumption of heat. It is important to have the air pass downward amongst the tumbling articles or material in the drum ii, rather than upward, since the tumbling opens them up in the top of the drum and allows the air to get in amongst them and pass through them in every direction of least resistance. If the air rose through the chamber l0, it would encounter the goods packed in the bottom of the drum i I, and would tend to spread out and pass up around the drum, rather than through the goods. It is also important to have the lint filter 33 close to or in the chamber III, as shown, to prevent any cooling of the solventvapor-laden air on its way from the goods to the lint filter, and any consequent condensation of the vaporous solvent-which would collect on the filter and greatly reduce the freedom of air flow through it, by matting the lint into a sort of felt.

Having thus described my invention, I claim:

1. Apparatus of the character described, for

recovering volatile solvents from material that has been treated therewith, comprising a treating chamber with a door in its front for the introduction and withdrawal of goods to be treated; a rotating foraminous-walled tumbling drum for the goods in said treating chamber. with an end opening adjacent said door; a rotary fan adjacent said treating chamber, with its suction intake connected into the latter below said drum; a lint filter removably mounted in said intake connection, between the fan and said drum; a delivery conduit from said fan extending upward past said treating chamber and connected into the latter above said drum; an air heater mounted in said conduit over said drum, adjacent the connection of the conduit into said drum; a c0ndenser interposed in said conduit between said fan and heater, with means for drawing off the condensate therefrom; and an air intake and an air vent for said conduit between said heater and drum and between said fan and said condenser,

respectively, with valve means for opening and closing them and for preventing chimney circulation of air through the conduit between them when they are open.

2. Apparatus of the character described, for' recovering volatile solvents from material that has been treated therewith, comprising a treating chamber with a door in its front for the introduction and withdrawal of goods to be treated;

' a rotating foraminous-Walled tumbling drum for livery conduit from said fan extending upward around one side of said treating chamber and connected into the latter above said drum; an air heater mounted in said conduit over said drum, adjacent the connection of the conduit into said drum; a condenser interposed in said conduit between said fan and heater, with means for drawing off the condensate therefrom; and an air intake and an air vent for said conduit between said heater and drum and between said fan and said condenser, respectively, with valve means for opening and closing them and for preventing chimney circulation of air through the conduit between them when they are open.

3. Apparatus of the character described, for recovering volatile solvents from material that has been treated therewith, comprising a treating chamber with a door in its front for the introduction and withdrawal of goods to be treated; a rotating foraminous-walled tumbling drum for the goods in said treating chamber, with an end opening adjacent said door; a rotary fan below said treating chamber, with its suction intake connected into the latter below said drum; a delivery conduit from said fan extending upward past said treating chamber and connected into its upper side above said drum; an air heater mounted in said conduit over said drum, adjacent the connection of the conduit into said drum; a condenser interposed in said conduit between said fan and heater, with means for drawing ofi the condensate therefrom; and an air intake and an air vent for said conduit between said heater and drum and between said fan and said condenser, respectively, with valve means for opening and closing them and for preventing chimney circulation of air through the conduit between them when they are open.

4. Apparatus of the character described, for recovering volatile solvents from material that has been treated therewith, comprising a casing having a treating chamber therein and provided with a door in its front wall, for the introduction and withdrawal of goods to be treated into and from said chamber; a rotating foraminouswalled tumbling drum for the goods in said treating chamber, with an end opening adjacent said door; a rotary fan in said casing underneath said treating chamber, with its suction intake connected into the latter below said drum; a lint filter removably mounted in said intake between said fan and said drum, and withdrawable through the front casing, wall; a delivery conduit from said fan extending upward around one side of said treating chamber in said casing and connected into. said chamber above said drum; an air heater mounted in said conduit over said drum, adjacent the connection of the conduit into said drum; a condenser interposed in said conduit between said fan and heater, with means for drawing OK the condensate therefrom; and an air intake and an air vent for said conduit I between said heater and drum and between said fan and said condenser, respectively, with valve means for opening and closing them and for preventing chimney circulation of air through the conduit between them when they are open.

5. Apparatus of the character described, for recovering volatilesolvents from material that has been treated therewith, comprising a casing having a treating chamber therein and provided with a door in its front wall for the introduction and withdrawal of goods to be treated into and from said chamber; a rotating foraminouswalled tumbling drum for the goods in said treating chamber, with an end opening adjacent said door; a rotary fan in said casing, with its suction intake connected into the treating chamber below said drum; a lint filter removably mounted in said chamber between said fan intake connection and said drum, and withdrawable through the front casing wall; a delivery conduit from said fan extending upward past said treating chamber in said casing, and connected into said chamber above said drum; an air heater mounted in said conduit over said drum, adjacent the connection of the conduit into said drum; a condenser interposed in said conduit between said fan and heater, with means for drawing oi the condensate therefrom; and an air intake and an air vent for said conduit between said heater and drum and between said fan and said condenser, respectively, with valve means for opening and closing them and for preventing chimney circulation of air through the conduit between them when they are open.

6. Apparatus of the character described, for recovering volatile solvents from material that has been treated therewith, comprising a casing having a treating chamber therein, and provided with a door in its front wall for the introduction and withdrawal of goods to be treated into and from said chamber; a base; a column in said casing extending up from the base behind said treating chamber to support the latter at the back; a drive shaft rotatably mounted in bearing means on said column, and a rotating foraminous-walled tumbling drum for the goods in said treating chamber, with an end opening adjacent said door mounted on the forward end of said drive shaft and overhung with respect to the shaft bearing means and said column; a rotary fan in said casing below said treating chamber, with a lateral suction connection therefrom forward and upward into said treating chamber below said drum; a driving motor mounted on said column behind said fan and directly connected thereto; a speed reducer mounted on said column; and driving belt connections from said motor to said reducer and from said reducer to said drive shaft.

'7. In apparatus for recovering volatile solvents from material which has been treated therewith, a horizontal axis casing constituting a treating chamber and having relatively-narrow longitudinally-extending inlet and outlet openings respectively at the top and bottom thereof, said openings being substantially coextensive in length with the chamber; a rotating horizontal axis foraminous-walled tumbling drum for the material in the chamber; a rotary fan below the treating chamber with a suction connection leading down from the bottom outlet opening of the casing; a delivery conduit with a straight vertical portion extending up from said fan at one side of the casing, and a straight horizontal portion extending over the casing from said vertical portion and connecting with the top inlet opening of the chamber; a heater within the horizontal portion of the delivery conduit immediately adjacent the top opening; a sump at the lower end of the

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