US2990030A - Dehydrator - Google Patents

Description

June 27,1961 J. R. M coY EIIAL 2,990,030

DEHYDRATOR Filed Aug. 20, 1958 4 Sheets-Sheet 1 I 1 27 I Y J! V A ,2

[ WEHfUFE June 27, 1961 J. R. MCCOY ETAL 2,990,030

DEHYDRATOR Filed Aug. 20, 1958 4 Sheets-Sheet 4 AVEN/0P5 JOA A/ P. M 60) 72/01/45 C WEE/VAT) JAIL/[5 AT LIW/IJ- United States Patent Ofiice Patented June 27, 1961 2,990,030 DEHYDRATOR John R. McCoy, Thomas C. Tiearney, and E. Lewis, Lebanon, Ind., assignors, by mesne assignments, to Commercial Filters Corporation, Melrose, Mass, a corporation of New York Filed Aug. 20, 1958, Ser. No. 756,185 5 Claims. (Cl. 183-25) This invention relates to improvements in a dehydrator, and more particularly to a dehydrating and degasifying apparatus highly desirable for use in removing water and gas from liquids such as insulating oils used in transformers, circuit breakers, switch gear, underground pipe.

type cables, and similar locations where dry oil is necessary to maintain high insulating characteristics, although the invention may be used to dry and degasify other types of liquids including mixtures of chlorinated diphenyls, silicones, polybutines, used in the impregnation of condensers or capacitors, as well as other liquids, all as will be apparent to one skilled in the art.

In the past, many and various types of dehydrators and degasifiers have been developed, and in the main these formerly known devices embodied a tank having a treated liquid outlet at the bottom and a connection to a source of vacuum at the top. The untreated liquid was usually admitted to the tank at an elevated temperature and in some cases permitted to flow over heated trays or the like within the tank, while in other cases spray nozzles were utilized to spray the untreated liquid under pressure into the interior of the tank. Frequently, these sprays disrupted vertically into the tank in the form of conical sprays, or the sprays were otherwise so located so that the spray patterns crossed each other.

The importance of removing substantially all water and gas content from an insulating oil is apparent when it is recalled that only a few water parts in a million parts of oil reduce the dielectric strength of the oil a considerable amount. These formerly known dehydrators, mentioned above, have proven objectionable for various reasons. Oil or other liquid that passed over heated trays or plates is not broken up into the fine fog or mist developed by a spray, and therefore that oil will not release its water content as thoroughly or quickly as where sorays are utilized. However, in the past the sprays were of such character as to converge or criss-cross each other within the tank, causing the tiny droplets of liquid to agglomerate or coalesce into larger droplets, whereby satisfactory removal of water and gas was rendered objectionably difi'icult.

Also, formerly known dehydrators frequently did not break up the liquid undergoing treatment into as fine particles as are desired, and failed to utilize nearly the available volume within the dehydrator. Such objections, of course, added materially to the cost and operation of these formerly known devices.

With the foregoing in mind, it is an important object of the instant invention to provide an economical and highly efiicient dehydrator and degasifier, capable of reducing the water and gas content of a liquid to a satisfactory operating level in a single pass through the device.

Another important object of the instant invention is the provision of a dehydrator capable of breaking the spray of the liquid undergoing treatment into extremely fine particles and maintain them in that condition until the water and gas have vaporized therefrom.

Also an important object of the instant invention is the provision of a dehydrator embodying a tank, and so constructed as to use substantially the entire interior volume of the tank above the treated liquid sump for spray dispersal purposes.

A further object of the instant inventiomand one equally as important, is the provision of spray patterns for incoming liquid to be treated such that substantially the entire transverse area of the tank is utilized for spray purposes, there is no danger of spray from one nozzle falling across or through spray from another nozzle, and wherein sprays from all of the nozzles are maintained separate and apart from each other.

A further object of the instant invention is the provision of a liquid dehydrator including a tank, and where in the spray patterns are transversely of the tank and extend throughout the major transverse area of the tank.

It is also a feature of the instant invention to provide a liquid dehydrator wherein the liquid inlet line is disposed adjacent the interior wall of the dehydrator and carries spray means aimed at the farthest Wall portion of the tank.

Still another object of the instant invention resides in the' provision of a liquid dehydrator embodying a tank from which the intake line and spraying mechanism are removable whenever desired while the remainder of the tank may remain permanently sealed around the discharge and vacuum outlets, if so desired.

Also a feature of this invention is the provision of a liquid dehydrator operating upon the spray principle, and containing a baffle assembly of economical and simple construction, yet which is highly efficient in preventing droplets or globules of the liquid undergoing treatment being carried out into the vacuum line.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawings, in which FIG. 1 is a top plan view of a dehydrator structure embodying principles of the instant invention;

FIG. 2 is a fragmentary side elevational view of the structure of FIG. 1, with a part of the casing broken away and parts shown in section;

FIG. 3 is a plan sectional view of the dehydrator taken substantially as indicated by the line IIIIII of FIG. 2, looking in the direction of the arrows;

FIG. 4 is an enlarged fragmentary vertical sectional view taken substantially as indicated by the staggered section line IVIV of FIG. 1;

FIG. 5 is a greatly enlarged fragmentary transverse sectional view through one of the spraying nozzles and the adjacent intake pipe taken substantially on the line V-V of FIGURE 3; and

FIG. 6 is a view in elevation of the discharge end of one of the spray nozzles.

As shown on the drawings:

In the illustrated embodiment of the instant invention there is shown a dehydrator and degasifier comprising a tank 1 closed at its top as indicated at 2, and at its bot tom as indicated at 3, by means of cover members which are preferably welded or equivalently positively secured to the tank body. The tank is preferably provided with a jacket 4 therearound to hold suitable insulation 5. The tank may be supported at any desired height from the floor by a plurality of suitable leg structures 6, seen in FIG. 2.

In the lower region thereof, at the bottom as illus trated, the tank is .provided with an outlet discharge fitting 7 for treated or conditioned liquid, this fitting being connected to any suitable pump line arrangement for redistribution of the treated liquid. The upper interior region of the tank is connected by a flanged fitting 8 with a suitable source of vacuum, which may be any good commercial pump capable of producing a high vacuum.

tank and projecting outwardly therefrom and carrying a flange on its outer end, this nipple furnishing the inlet port for liquid to be treated. As seen in FIGS. 1 and 3, the tank may also be provided with opposed sightglass assemblies 11 and 12 which are substantially midway of the height of the tank, and enable'the operator to ob serve the movement of the liquid undergoing treatment inside the tank. i

Liquid is admitted into the tank for treatment through a pipe 13 depending from a flange 14 providing a cover disposed over the aforesaid flange 10 on the intake nipple 9. This pipe is preferably plugged at its lower end as indicated at 15 in FIG. 2, and extends down to a point substantially at the desired level of treated liquid in the bottom of the tank. It will be noted from the showings particularly in FIGS. 1 and 3 that the pipe 13 is disposed adjacent the interior wall of the tank, or, in other words, at one side of the tank. The pipe 3 communicates by way of a pressure pump with a source of liquid to be treated, and in the illustrated instance such communication is established by Way of a flange 16 overlying the flange 14 and having a threaded aperture 17 therein which is aligned with the top of the pipe 13, as seen best in FIG. 2. It will, of course, be understood that suitable gasket means are utilized between the flanges 10, 14 and 16. These flanges may be connected together in a removable manner in any desired fashion, such as by bolts 18. Inside the tank, the pipe 13 is provided with a plurality of vertically spaced spray nozzles 19, and the aforesaid nipple Si is of sufiicient size to permit the withdrawal of the pipe 13 and the nozzles, when desired, for inspection or replacement purposes. Otherwise, the tank is preferably fully sealed.

With reference now to FIGS. 5 and 6, it will be seen that each of the nozzles 19 embodies a hollow body 20 having a shank portion threaded through a suitable aperture in the wall of the intake pipe 13, as indicated at 21. While these nozzles in and of themselves or individually form no part of the instant invention, except by way of their association with the other structures, it should be noted that each nozzle is of such a character as to produce a fiat fan-shaped spray. To this end, it may be mentioned that each nozzle comprises a suitable core 21a flanged at its outer end and held in place within the body 20 by a nozzle 22 and an inwardly flanged bushing 23 threaded to the body. The aperture through the nozzle gradually decreases in size until it terminates at its finest diameter in a flat jet-like opening 24 having inwardly converging top and bottom walls, and an external opening in the nature of a flattened oval as seen in FIG. 6. Such structure causes the spray nozzle to produce a fiat fan-like spray as indicated at 25 in FIG. 4, and by the dotted lines 26 in FIG. 3, which flat spray, since there is a high vecuum in the upper part of the'tank, extends clear to the far wall portions of the tank. Therefore, the spray covers the major cross-sectional area of the tank as evinced by the dotted lines 26. In most cases, the spray actually strikes against the wall of the tank at the farthest point from the nozzle, and remains in substantially a transverse plane until so striking the wall, when the sprayed liquid gravitates down the wall toward the tank bottom.

In order to prevent any fine particles of the liquid undergoing treatment to escape through the vapor outlet 8 connected with the vacuum line, a baffie assembly is provided within the tank above the nozzles 19 This bafiie assembly may merely be seated upon a ring or flange secured to the inside wall of the tank, as shown at 27 in FIGS. 2 and 4.

The bafiie assembly itself comprises like lower and upper plates 28 and 29 each of which is provided with a myriad of preferably evenly spaced perforations 30 throughout its central area, with the exception of that region of the plate in the immediate vicinity of the intake Pi e h Plates 8 an 9 ar 4 9 Pref abl 9? substantially the same area as the cross-sectional area of the casing, as seen best in FIG. 3. Between the perforated plates 28 and 29 is an imperforate plate 31 which is of lesser diameter than the perforated plates, as seen in FIGS. 3 and 4. The bafile plates are maintained in a unitary assembly by means of suitable bolts, 32, hollow spacer elements 33 being utilized to maintain all of the plates in vertically spaced relationship with each other. The entire baffle assembly may therefore be placed in position as a unitary structure when the dehydrator is being assembled.

In operation, the instant invention is extremely simple and highly efiicient. Liquid to be dehydrated and degasified is pumped through the inlet pipe 13 under pressure and at an elevated temperature. This liquid is then atomized or reduced to a fine fog or mist through the sprays from the nozzles 19. Due to the elevated temperature and vacuum, water particles will readily separate from the very fine particles of other liquid, vaporize, and pass out through the fitting 8. Such vaporous particles will follow a course through the bafile assembly as gen.- erally indicated by the dotted and arrowed line 34 in FIG. 4. Any particles or droplets of the liquid being treated which are of sufiicient fineness to move toward the vapor outlet will contact one or more of the plates 28, 29 and 31, and coalesce into droplets too large to be carried over into the vacuum line. Such droplets will then gravitate to the pool of treated liquid at the bottom of the tank. Thus, none of the liquid being treated can be carried over into the vacuum line with the instant spraying and bafiling arrangements.

The eifectiveness of the instant invention is greatly enhanced by virtue of the fact that the liquid undergoing treatment will be reduced to an extremely fine mist or fog by the spray nozzles 19, and be distributed throughout the major volume of the tank in flat horizontal fanlike sprays which do not criss-cross or converge with and meet any other spray. Owing to the vacuum in the tank and the pressure involved, the various sprays 25 from the nozzles will remain substantially parallel and out of contact with each other until they strike the interior wall of the tank. Thus, there is no opportunity for agglomeration or coalescence of the droplets of liquid into larger particles from which it is extremely difiicult to release the water or gas. The fine mist or fog of these separated sprays releases any water or gaseous content very readily.

The number of nozzles utilized on the intake pipe varies according to the particular job the dehydrator is to perform. If a finished oil which has the nearest minimum amount of water obtainable therein after treatment is desired, a large number of nozzles is used, and the lower the flow rate per nozzle, the better the dehydration. The pressure utilized as well as the temperature also depend to some extent upon the character of liquid undergoing treatment. For example, insulating oil of the type utilized in transformers, circuit breakers, and the like may be heated to l40-150 F., while cable insulating oil is preferably heated to approximately 200 F owing to its greater viscosity.

By way of example and not by way of limitation, it may be mentioned that for ordinary transformer oil, spray pressures ranging from to 150 lb. per square inch, and a temperature from to F., with a vacuum of approximately 28 inches, produces satisfactory results. For critical work, however, larger vacuum pumps could be utilized which would maintain the vacuum in the dehydrator ranging somewhere between 100 and 1,000 microns absolute pressure; the temperature might be increased to as high as 200 F., and the pressure at the nozzles might be increased approximately to 200 lb. per square inch. The results would be more eifective than with the example just previously given. With the instant invention, it is possible under good operating conditions to reduce the water content of the liquid undergoing treatment down to less than five parts per million, and the gas content to less than 1%, in a single pass of the liquid through the dehydrator. It makes no difference whether new or used liquid is being processed, since with the instant dehydrator such liquid may be reprocessed indefinitely.

Obviously, if the liquid is not removed from the tank as fast as it enters, and the level of processed liquid in the tank should rise above the nozzles, the dehydration would not be desirably effective. With that in mind, it is preferable to equip the dehydrator with a float switch assembly 35 which may be of a known commercial type, but which is installed in such a manner as to cut ofi the supply of liquid to the tank when the level reaches a predetermined height, or cut off both the pumps in the supply line and the discharge line, if such might be desired.

The sightglass arrangements 11 and 12 permit the operator to ascertain the functioning of the nozzles at any time. Should any of the nozzles need servicing, it is a simple expedient to release the bolts 18, remove the plate 16, and lift out the plate 14 together with the intake pipe 13 and the nozzles attached thereto, the baffle arrangement being perforated to permit this operation as indicated at 36 in FIG. 3. The nozzles may then be serviced or replaced, and the intake assembly again mounted within the tank. Thus, servicing of the nozzles, which are substantially the only parts that may ever require servicing, may be easily accomplished with a minimum amount of shutdown time.

From the foregoing, it is apparent that we have provided a dehydrating and degasifying apparatus which is extremely eflicient in operation and economical to use. It will be noted that the liquid undergoing treatment is reduced to a minimum mist or fog and maintained in thin flat parallel sprays with no opportunity to agglomerate or coalesce during the time necessary for it to release the water and gaseous content. At the same time, liquid undergoing treatment cannot be withdrawn through the vacuum line by virtue of the eflicient and simple bafile assembly. It will also be apparent that all of the available interior volume of the tank for spraying and dehydrating purposes is fully utilized, and the entire structure, consistent with its ease of operation and high efliciency, may be economically manufactured.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

We claim as our invention:

1. In a dehydrator, a tank having an outlet discharge opening for dehydrated liquid in the bottom, a connection for a vacuum line at the top of said tank, an inlet pipe for untreated liquid extending vertically into said tank adjacent the wall thereof, a plurality of spaced nozzles on said pipe aimed toward the far side of the tank, each said nozzle being shaped to provide a flat fan-like spray in the form of a fine mist shooting substantially hori zontally, said nozzles being spaced to maintain all of the fine mist sprays separate from each other, and bafile means including a lower perforated plate and an upper spaced imperforate plate of less area mounted in said tank above the nozzles and below the vacuum line connection.

2. In a liquid conditioning apparatus, a tank having an opening in the lower portion for the discharge of treated liquid, a pipe for untreated liquid extending into said tank, spray means on said pipe arranged to provide a plurality of spaced fan-like non-converging fine mist sprays of the liquid substantially transversely of the tank, and means to connect the upper interior of the tank above said spray means with a source of vacuum.

3. In a liquid conditioning apparatus, a tank having an outlet opening for treated liquid near one end and a vapor outlet opening for connection to a vacuum line near the other end thereof, inlet means for untreated liquid extending into said tank, and spaced spray means connected with said inlet means between said outlet openings and arranged to provide a plurality of separate nonconverging flat fan-like fine mist sprays of the liquid across the tank generally transversely of a path between said outlet openings.

4. In a liquid dehydrator, a casing having a discharge opening for treated liquid at the bottom thereof, a generally vertical liquid line for untreated liquid extending into said tank adjacent the wall thereof, spray means on said line aimed at the farthest wall portion of said tank and arranged to discharge incoming liquid in a series of vertically spaced substantially horizontal non-converging substantially flat fan-like fine mist sprays over most of the width of the tank, and said tank having a vapor discharge port at the top thereof.

5. In a method of dehydrating oil, spraying a plurality of substantially fan-like fine mist sprays of the oil to be dehydrated across the interior of an enclosure and with the fan-like sprays spaced from one another and nonconvergent, drawing a vacuum through the non-convergent sprays to remove moisture from the mist droplets of oil, collecting the dehydrated droplets of oil, and withdrawing the dehydrated oil from the enclosure.

References Cited in the file of this patent UNITED STATES PATENTS 2,201,870 Piercy et al May 21, 1940 2,257,945 Fraser Oct. 7, 1941 2,448,128 Trageser Aug. 31, 1948 2,573,966 Hamlin Nov. 6, 1951 2,642,950 Clark et al. June 23, 1953 2,714,938 Smith Aug. 9, 1955 2,733,961 Rhinehart Feb. 7, 1956 2,797,767 Brooke et a1. July 2, 1957 2,868,523 Cundifi et al Ian. 13, 1959

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