US2003397A - Moisture extraction - Google Patents

Description

June 4, 1935. H. L. SMITH, JR

MOISTURE EXTRACTION Filed July 17, 1934 2 Sheets-Sheet l I M, Dav-v INVENTOR HIS ATTORNEYS June 4, 193 5.

H. L. SMITH, JR 2,003,397

I MOISTURE EXTRACTION Filed July 17, 1934 .2 Sheets-Sheet 2 7'0 EVACUATOA ll: E::

\NVENTOR 24M 0 Mac M: ATTORNEYS Patented June 4, 1935 UNITED STATES PATENT OFFICE MOISTURE ax'mao'non Horace L. Smith, Jr., Richmond, Va., assignor to Thermal Engineering Corporation, Richmond, Va., a corporation of v t Application July 17, 1934, Serial No. 735,718 3 Claims. (01. 3H8) This invention relates to the extraction of of steam in the ejector and the contamination moisture, and more particularly concerns imof the ejector condensate by the foreign matter. proved apparatus for withdrawing moisture from Another object of the invention is the procloth, fabrics or other materials which are pervision ofan improved type of vacuum chamber 5 meable to air. for use with moisture extracting apparatus of 5 In many manufacturing processes, it is necesthe type described. sary to extract moisture from air permeable ma- In general, the above and other objects of my terials. Thus in the finishing of textiles, a web invention are carried out by providing moisture of textile fabric is subjected to one or more water extraction apparatus inclu n a v m mrinsing operations prior to sizing or other treatber into which the air and entrained water are 10 ment, and it is essential that the moisture abdrawn from the fabric or other moist permeable sorbed by the fabric during rinsing be removed material under treatment, and by providing therefrom before the sizing or other treating mans for c n inu ly re v from this terial is applied. It has been customary to exchamber the extracted water and the fore l5 tract this moisture by continuously passing the matter carried thereby Without Passing this wet material over a slot or similar opening in a water through t e exhausting D p other chamber in which a vacuum is maintained by vacuum producing means. pumps or equivalent means, whereby the mois- In a preferred form of my invention, this is ture in the fabric is entrained and withdrawn by accomplished by connecting the pump or other the air drawn therethrough into the vacuum vacuum produ means to a point above the 20 chamber. This water withdrawn from the fabbottom of the vacuum chamber and by Providing ric contains a large amount of lint, threads, dye an extracted water outlet means comp in a and other foreign material which is withdrawn downwardly extending duct of considerable length from the vacuum chamber by the vacuum pump. connected at its upp end to a point at This foreign matter collects on the pump screens jacent the bottom of the vacuum ch m r an 25 and stops the pumping action or, if no screens having an air seal or trap at its lower end. with are used, clogs and injures the pumps and causes this arrange the Waller other q d frequent shut-downs or breakage of apparatus. tracted from the material under treatment, to-

It has been proposed to overcome the above exg t c w t foreign matter carried e y.

plained difficulty by using steam jet ejectors for continuously flows off by gravity through the 30 maintaining a vacuum within the vacuum moisoutlet duct, and the water seal provided by this ture extracting chamber. Although the use of water at the lower end of this duct prevents the such-ejectors avoids clogging difficulties to a ceregress of air through the duct to the vacuum tain extent, it is unsatisfactory in other respects. chamber. The pump or other means for main- Thus a large amount of steam is required to optaining a vacuum in the chamber withdraws the 35 erate a steam ejector even under ordinary opentraining air only from this chamber and accrating conditions, and the fiow of extracted cordingly, the invention entirely prevents the conwater into the ejector condenses some of .the densation of steam and contamination of consteam therein before it has performed its ejecdensate in an ejector type of exhauster, as well tion function, thereby greatly increasing the as the clogging of a pump exhauster. 40 steam consumption of the ejector. Further, since In a modified form of the invention, the vacuum the water passing through the ejector is contamchamber is provided with a combined water and inated with lint, dye and other foreign matter air outlet opening so shaped as to aid in sepaextracted from the fabric, the hot water conrating the extracted moisture from the entraining densed from the ejector exhaust is unfit for most air as these fluids leave the chamber. In a fur- 45 uses and is accordingly wasted. ther modification of the invention, the moisture With the above and other considerations in extracting or inlet opening of the vacuum chammind, it is proposed in accordance with the presber is so arranged as to prevent the distortion of ent invention to provide improved apparatus for this inlet by the vacuum maintained within the extracting moisture from air permeable materials chamber. 50 such as cloth or other fabric, which apparatus, The invention will be best understood by referwhile. effectively removing the moisture, entirely ence to the accompanying drawings, in which ceravoids the clogging. of screens or pumps by fortain embodiments thereof have been disclosed; eign matter in the extracted moisture, the low- In the drawings;

ering of ejector efficiency by the condensation Figure 1 is a diagrammatic representation of a 55 fabric treatment to which the moisture extraction apparatus of the present invention is applicable;

Figure 2 is an elevation, partly in section, of the moisture extraction apparatus embodying the invention;

Figure 3 is a plan view, partly in section, of the apparatus shown in Figure 2;

Figure 4 is a plan view, similar to Figure 3, showing a modified form of apparatus embodying the invention;

Figure 5 is a sectional elevation of a modified form of moisture extracting apparatus embodying the invention, the section being taken along the line 5-5 of Figure 6; and

Figure 6 is a plan view of the apparatus shown in Figure 5 disclosing my improved vacuum chamber inlet slot construction.

The moisture extraction apparatus of the invention may be used wherever it is desired to withdraw moisture from air permeable material. One important application of this apparatus is in the finishing of woven textile materials. It is customary to thoroughly rinse certain textile fabrics with water prior to the application of starch or sizing thereto or other treatment thereof, and it is usually essential that the rinse water be removed before the fabric is subjected to further treatment. In one fabric treating process as illustrated in Figure 1, a continuous Web 5 of textile fabric is moved between rinse water sprays 6 which thoroughly saturate the fabric, after which the web passes over a guide roll 1 and over a. stationary moisture extracting cylinder or vacuum chamber 8. The chamber 8 is provided with a very narrow slot 9 along the upper cylindrical surface thereof, this slot being substantially coextensive with the width of the fabric web, as shown in Figures 2, 3 and 4. A vacuum is maintained within the chamber 8 by means hereinafter described, and air is accordingly drawn through the fabric as it passes over the slot 9 with the result that the water carried by the fabric is entrained in the air and drawn out of the fabric into the chamber 8. The fabric web 5 then passes through a sizing bath l0 under a suitable roll I I and'is delivered to drying or other treatment means, not shown, over the guide roll l2.

The apparatus of the present invention acts to maintain the desired vacuum in the chamber 8 by continuously removing the entraining air and the extracted water from this chamber. The vacuum creating means may comprise a vacuum pump, a steam ejector or any other device capable of continuously withdrawing air from the chamber 8 at a suitably high rate of flow.- In the embodiment of the invention shown in Figure 2, a steam jet ejector, generally designated J, is employed for maintaining a vacuum in the chamber 8. This form of evacuating means is particularly adaptable in many textile finishing plants where heated water is'employed in various treating processes, since the hot water recovered from the ejector may be usefully employed in such plants.

The ejector J may be of known construction and as shown comprises a steam nozzle l3 located in a chamber l 4 and disposed to direct a high velocity steam jet axially through a contracted throat or Venturi tube l5. In accordance with the invention, the suction pipe l6 of the ejector is connected to the vacuum chamber 8 at or adjacent the top thereof, and as shown in Figure 2. this pipe is connected to the upper surface of the chamber 8 adjacent one end of the chamber and communicates with the chamber ll of the ejector adjacent the nozzle l3. Steam is supplied to the ejector nozzle l3 from a suitable source through the pipe l1.

The outlet or exhaust pipe 18' of the ejector J is connected to suitable condensing means illustrated at C. The condenser may take any suitable form and as shown comprises a chamber [9 communicating with the ejector exhaust pipe l8 through an inlet opening 20 at its upper surface adjacent one end thereof, and a condensate outlet 2| in its lower surface adjacent its opposite end. Cooling water is sprayed into the inlet end of the chamber l9 through a pipe 22 and small auxiliary water sprays 23 are provided at spaced points along the center of the chamber. An air outlet opening 24 is provided at the outlet end of the condenser chamber as shown. In operation, the

air and steam delivered by the ejector exhaust l8 passes through the condenser chamber IS, the steam is condensed by the water sprays and the mixed condensate and spray water flow off through the outlet 2 I, the air passing out through the opening 24.

By properly designing the condenser, the water recovered therefrom maybe delivered at a comparatively high temperature and usefully employed in various processes such as those incident to the finishing and manufacture of fabrics.

As explained above, the water extracted from the fabric web 5 is contaminated with lint, threads, dye and other foreign matter. If this contaminated water passed through the ejector J, the hot water recovered from the ejector exhaust would be unfit for use in most manufacturing operations. Further, if the comparatively cold water extracted from the fabric passed into the ejector chamber H, it would come into direct contact with and condense some of the steam in the jet from the nozzle l3 before this steam could perform its propelling function in the throat Hi. In accordance with the present invention, the water extracted from the fabric is separated from the entraining air in the vacuum chamber 8 and is continuously removed from this chamber without passing through the exhausting mechanism and without either breaking the vacuum in the chamber or employing pumps or equivalent propelling means.

In order to remove the contaminated extracted water, I provide a liquid column in a vertically extending duct 25 connected at its upper end to a point adjacent the bottom of the vacuum chamber 8, and having a liquid seal or trap at its lower end. The liquid seal or trap may comprise a reverse bend at the lower end of the duct 25 the upwardly extending leg of the duct being shorter than the downwardly extending leg thereof as shown. The outlet of the duct may be connected to a sewer or other waste water receiver.

In the.operation of the apparatus described. the water saturated fabric web 5 passes over the slot 9 in the vacuum chamber 8 and the vacuum created within the chamber 8 by the ejector J causes air to flow at a high velocity through a limited area of the fabric thereby entraining and extracting water therefrom. The slot 9 is very narrow. in practice it may be from .005 to .064 inches wide. Accordingly, although the velocity of the air and entrained water through the slot it- 'self is very high, this velocity immediately drops to a much lower value as'the air and water enter the chamber 8. At this point, the extracted water falls to the bottom of the chamber 8 and flows off by gravity to the duct while the entraining air is drawn off through the ejectoras explained above. The duct 25 is so designed as to vertical extent and cross section that the water column built up therein by the vacuum in the chamber 8 is capable of balancing the highest vacuum which the ejector apparatus can establish in the vacuum chamber. Thus the water outlet duct is always sealed, and at the same time permits the continuous flow of extracted contaminated water from the chamber 8.

As explained above, pumps or other mechanica exhausting means may be used on my improved moisture extracting apparatus. This embodiment is disclosed in Figure 4 wherein an exhaust or vacuum pump, conventionally represented at P, is connected through a duct I6 with the upper surface of the vacuum chamber 8'. The chamber 8' is provided with a trapped water column outlet duct 25' which may be identical with the duct 25 of Figure 2. With this arrangement, the contaminated water separates by gravity from the entraining air in the vacuum chamber 8' and flows off through the duct 25', and the clogging or injury of the pump-P by the lint and other foreign matter in the extracted water is effectively avoided.

In a modified form of the invention, as shown in Figure 5, the vacuum chamber 21 is provided with a single outlet 28 at one end thereof through which both the entraining air and the extracted moisture pass, and which is so shaped as to aid in separating the moisture from the air at this point. Thus the outlet end of the vacuum chamber 21 communicates directly with the downwardly extending water outlet pipe or duct 29 and the upper surface of the chamber outlet duct 28 is curved downwardly as shown at 30 toward the upper end of the pipe 29. Just beyond this downward curve, the duct 3| leading to the evacuator is joined to the vacuum chamber outlet duct 28 and the water outlet 29, the arrangement being such that in entering the air duct 3|, the airmakes a U-bend and substantially reverses its direction of fiow'. With this arrangement, as the stream of air and water flows out of the vacuum chamber. 21 through the duct 28, this stream is deflected downwardly toward the water outlet pipe 29 and the water in the mixture, being considerably heavier than the air, continues to flow downwardly into the pipe 29 while the lighter air passes upwardly around an acute angle bend into the air duct 3i to the evacuator. It is, of course, to be understood that a steam jet ejector, vacuum pump or other type of evacuator is connected to the air duct 3!.

A modified form of water seal for the water outlet duct is disclosed in connection with the apparatus shown in Figure .5. This seal comprises a large tank or other receptacle 32 in wh ch the lower end of the pipe 29 is submerged. The ca- I pacity of the tank 32 is such that when it is filled to the level of its overflow pipe 33 and the evacuator is started, the column of 'water drawn up in the pipe 29 will not empty the tank 32 to a point where the lower end of the pipe 29 is uncovered. In other words, the tank 32 has a greater volumetric capacity than the pipe 29 or at least a greater capacity than that portion of the pipe 29 which is filled with water when the evacuator is in operation. With this arrangement, when the moisture extracting apparatus is started up after an idle period, the water seal in the pipe 29 is not broken and the required vacuum is quickly built up in the chamber 21 regardless of the rate of flow of extracted liquid into the upper end of the pipe 29. a The water seal disclosed in Figure 5 is, of course, applicable to all modifications of my improved moisture extracting apparatus.

Another featm'e which is applicable to all forms of apparatus embodying my invention is an improved inlet opening for the vacuum chamber which is illustrated in Figure 6. In order that the entraining air shall pass through the web 5 at a very high velocity and thus extract substantially all of the moisture therefrom, it is desirable that the slot be extremely narrow and that a high degree of vacuum be maintained in the chamber 21. With the apparatus designed to handle a web 5 of considerable width, there is some danger that the vacuum-chamber may collapse due to the vacuum therein to such an extent that the inlet slot or portions thereof are contracted or closed, thus interfering with the moisture extracting operation. It is difficult and expensive to brace or reinforce a continuous slot without placing obstructions in the path of the air and entrained water drawn therethrough. In accordance with one feature of my invention, I overcome the above noted difliculties by forming a plurality of comparatively short slots 34 in the surface of the vacuum chamber 21, these slots being disposed with their ends in overlapping relationship, as shown in Figure 6, and being closely spaced so that the web 5 extends over all of these slots. I prefer to arrange the slots 34 as shown in substantially parallel relationship and at a slight angle to the axis of the vacuum chamber. With this arrangement, a bridge of metal, indicated at 35, extends between the ends of the adjacent slots and prevents the closing of the slots due to the collapse of the vacuum chamber. The individual slots may be of any desired length short of that at which there is danger of restriction or closing thereof and any desired width of web may be handled by increasing the number of overlapping slots employed. Since the ends of the adjacent slots 34 overlap transversely of the web, moisture is extracted fromthe web across its entire width.

Although the invention has been described in connection with certain forms of apparatus employed in the extraction of water from textile fabrics, it should be understood that the invention is generally applicable to any operation in which water or moisture are extracted by the suction of air through the material under treatment, and that various changes and omissions may be made in the apparatus used without departing from the scope of the invention as defined in the appended claims.

jacent its upper surface, means for condensing steam from said ejector and a downwardly extending water outlet duct having its upper end in communication with said chamber adjacent the lower surface of said chamber and having a reverse bend adjacent its lower end.

2. Apparatus for extracting moisture from permeable material comprising a vacuum chamber having a restricted inlet opening therein, means for continuously moving moist air permeable material over said opening, a steamjet ejector having an inlet duct connected to said chamber adjacent its upper surface, means for condensing steam from said ejector, a downwardly extending water outlet duct having its upper end in communication with said chamber adjacent the lower surface of said chamber, and a water seal at the lower end of said duct.

3. Apparatus for extracting moisture from permeable material comprising a vacuum chamber having a restricted inlet opening therein, means for continuously moving moist air permeable material over said opening, a steam jet ejector having an inlet duct connected to said chamber adjacent its upper surface, means for condensing steam from said ejector, a downwardly extending water outlet duct having its upper end in communication with said chamber adjacent the lower surface of said chamber and a receptacle surrounding the lower end of said duct and having a volume above the lower end of said duct at least equal to the volume of liquid carried by said duct.

' HORACE L. SMITH, JR.

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