US2013607A - Internal ejector - Google Patents

Description

Sept. 3, 1935. c HAWLEY 2,013,607

INTERNAL EJECTOR Filed Nov. 9, 1954 INVENTOR gwles Q ATTORNE s Patented Sept. 3, 1935 INTERNAL EJECTOR Charles Gilbert Hawley, Chicago, Ill., assignor to Centrifix Corporation, Cleveland, Ohio, a corporation of Ohio Application November 9, 1934, Serial No. 752,353

4 Claims.

This invention relates to improvements in steam purifiers as used within steam boilers. Purifiers of the so-called open type are so employed and are positioned within the upper part of the steam-and-water drum, providing the avenue through which steam leaves the drum; meantime functioning to exclude and to separate entrained boiler water, to the end that the steam shall be discharged from the boiler in a clean, dry state. As matter of course, the separated moisture must be constantly discharged from such purifier, otherwise liquid would escape with the steam and defeat the purpose of the purifier.

It is a simple matter to arrange for the discharge of the separated liquid by means of one or more drainpipes leading from the purifier, passing through the wall of the drum and connected to any suitable discharge trap upon the exterior of the boiler. But that practice entails added expense and results in the waste of hot boiler water and consequent waste of heat. Therefore, in most cases, it is desirable to eject or return the separated water from the purifier to the interior of the boiler, and preferably, directly into the main body of water occupying the steam-and-water drum. Obviously, by so doing savings of two kinds are accomplished.

Whenever the pressure within the purifier and drain is only slightly less than that existing within the steam space of the boiler, the separated water may be effectively discharged through one or more short drainpipes which are extended from the purifier to a point or level well below the surface of the water in the drum. But this simple arrangement is likely to be inefficient in boilers that are operated at high ratings, for in such cases the ejecting or draining action is often defeated by'a lowered pressure within the purifier and particularly by the agitation and turbulence of the boiler water wherein the open lower end of the drain is submerged. Either excessive pressure drop through the purifier or conflicting hydraulic disturbance working upward from the bottom of the drum may cause boiler water to ascend through the drainpipe instead of falling therein, as required to clear the purifier. s

The present purpose is to overcome the above defined difficultiesand as will become apparent this purpose is accomplished, first, by employing a purifier that opposes little resistance to the passage of the steam, yet effectively separating the entrained moisture, and second, by shielding or protecting the submerged open lower end of the drainpipe from hydraulic disturbance; in

other words, in such manner that the column of water always occupying the lower part of the drainpipe is little, if at all, disturbed by the erratio currents which surge about its submerged end. Thus the purifier is adapted to work effectively at all rates of boiler operation, and without waste of water or heat.

The invention, as best practiced, will be more readily understood upon reference to the drawing that forms part of this specification.

In said drawing, Fig. 1 is a vertical section of the steam-and-water drum of a typical steam boiler and shows a steam purifier installed therein in accordance with the present invention;

Fig. 2 is a partial, vertical section upon the line 22 of Fig. 1, viewed in the direction of the arrow 2a; Fig. 3 is a fragmentary vertical section like unto Fig. 1 but showing ejector protecting means of a slightly different form; and, Fig. 4-

is a like view illustrating still another modification of the invention.

A conventional steam-and-water drum, marked 2, is distinguished by steam-and-water tubes 3 entering its upper part and by water circulating or exit tubes l always leading from the bottom of the drum. At the top of the drum is the steam outlet or nozzle 5 with which the steam purifier 6 is associated, such purifier providing the avenue through which the steam from the steam space S passes to the boiler nozzle 5 and functioning to remove or separate the steam-entrained boiler water in advance of said nozzle.

As preferred and as here shown, the purifier 6 is of the non-rotative centrifugal type, well known as Centrifix, distinguished by a circumferential series of tangential steam entrance tuyeres 6a and by separating races or spaces at both top and bottom, the latter serving to receive the entrained moisture which is centrifugally separated by the vortexial action of the steam passing through the purifier; an action occasioned by the tangential or whirling entrance of the steam. Such a purifier usually has two drainpipes l, l and, importantly, serves to deliver the separated water into such pipes under pressure conditions almost equalling that within the open steam space S. Thus it becomes feasible to extend short drainpipes l, 1 directly downward within the boiler drum 2, where their open ends I are submerged within the boiler water W.

Little space remains between the bottom of the purifier and the surface D of the water for the diameter of a water-tube boiler drum is not great; and obviously, under the most favorable of conditions the water rises within the pipes l and to a level or levels always above the steam disengagement surface D. Clearly, and as here described, it is important to select and employ a purifier which minimizes the rise or stand of water within the drain pipes, making possible the continuous downward movement of the separated water; which must be discharged if the purifier is to continue to operate as expected. This much has been done in boilers operating at usual ratings but where boilers are operated at very high ratings there is need of further means to ensure the downward discharge of water through the purifier drain pipe or pipes. This is due to the nearness of the steam disengagement surface, D, and to the violent agitation of the boiler water which takes place when the boiler is forced. Under such conditions the hydraulic forces of the many conflicting currents within the body of boiler water cause variations in the amount and direction of fiow within the open drain pipe or pipes; sometimes causing water to rise into, instead of being discharged from, the purifier.

The object of the present invention, and its effect, is to overcome these diificulties and to maintain substantially constant conditions of discharge within and from the drainpipe or pipes. This for- Ward step, as hereinafter described, entails the protection, removal or defense of the open end of the drainpipe from the surging forces of the boiler Water and thereby the constant downward discharge of separated water is ensured. To such end it has already been proposed to extend the drainpipe welldownward into the return or exit tube of the boiler and some benefit has been gained by so doing. But such arrangement is not uniformly successful and is open to the objection that it is an awkward matter to install the extended drainpipe, often crooked; and, to the objection that when so installed the presence of the pipe restricts the effective area or capacity of the exit tube and thus tends to divert the return fiow to other and unobstructed exit tubes of the boiler, endangering the life of the occupied tube.

The specific object of this invention is to avoid all difficulties, particularly including those last above mentioned. This I accomplish by terminating the drainpipe or pipes 1 short of the bottom of the boiler drum and within an intervening uni-directional flow space or cavity, itself in free communication with the interior of the drum and forming the entrance of one or more of its return or water exit tubes 4.

The details of this new construction may be varied to suit different boilers and boiler conditions but each thereof must be characterized by the described uni-directional space or cavity which receives the lower end of the drainpipe and quite completely protects it and the exit tube 4 from surging hydraulic forces that otherwise would or might prevent the proper operation of the steam purifier. By way of example, three diiferent cavity constructions are illustrated in Figs. 1, 3 and 4 of the drawing, wherein, for purposes of easy identification each of these isolating or uni-directional cavities is marked A.

In the case of Figs. 1 and 2, the described antisurge or isolating cavity A is formed by an open bottomed box 3 which rests upon the bottom of the boiler drum covering one or several of the downward opening exit tubes 4. In the top of the box are openings 9 which receive the lower ends of the drainpipes 7, 1. In the case of Fig. 3, the cavity is formed by a smaller box it and completed by a spaced baflle ll, while in the case of Fig. 4 the cavity is formed by an open bottomed box or inverted pan I2, likewise receiving a drainpipe and covering one or more exit tubes 4. In every case the box contains or provides a water entrance perforation or openings of restricted size yet in the aggregate ample to represent and supply the exit tube or tubes covered; and through which the water from the body of the drum may flow freely into the cavity A and the exit tube or tubes 4.

It is of advantage that these boxes may be extended laterally and longitudinally so that the downflow from the drainpipe or pipes shall be dispersed and distributed to a number of exit pipes, particularly where the latter are of relatively small size.

In the case of Figs. 1 and 2, the interconnecting opening l4 takes the form of a sufficiently capacious slot in the end portion of the box 8 and the construction of Fig. 3 is characterized by' an open ended box It; its entrance passage 15 being defined by the end of the box it! and the fixed baffle H, spaced therefrom. The box IE of Fig. 4 resembles an inverted pan, receiving the end of the drain pipe and containing the required number of small openings .16, by which latter communication is established between the body of the boiler and the cavity A.

It will be noted in each case the described box rises upon the floor of the drum and serves to protect or defend both the lower end of the purifier drainpipe and the upper open end of the boiler return or exit tube 4. In other Words, surging water having suflicient force to disturb conditions within the pipe 1 and tube 4 are diverted and excluded by the presence of the perforated cavity forming box. Thus it is ensured that the downflow through both the exit tube and the drainpipe shall be persistent and undisturbed.

In every case the openings which are provided in the top of the box for the reception of the drain tube or tubes are large enough to permit of the escape of any steam that may be trapped within the cavity A, and additional openings may be provided for that purpose when deemed necessary.

From time to time the boiler tubes must be cleaned and this invention provides therefor by making the interconnecting or shielding box readily removable, so that cleaning tools may be used in the normally covered return tubes 4.

As shown in Figs. 1 and 3 the box may be secured to the bottom of the drum 2 by means of a hinge l1, I3, permitting the box to be swung upward and to one side after the drain tubes 1 have been removed, by unscrewing them from the purifier. Similarly, in the case of Fig, 4, the box l2 may be lifted away from above the normally covered tube 4 as soon as the drain pipe I is removed. The rigid drainpipe normally serves to prevent lateral displacement of the inverted pan l2 and the downward pressure of the water upon the pan serves to hold it properly against the bottom of the drum. No side fastenings are required.

Having thus described my invention I claim as new and desire to secure by Letters Patent:

1. The improvement herein described comprising a boiler drum with its steam outlet and a water exit tube, the latter leading from the bottom of the drum, in combination with a steam purifier positioned within said drum and connected to said outlet, a drainpipe lea-ding from said purifier toward the bottom of the drum and terminating above the open end of said exit tube, and a box-like element forming an intervening uni-directional water exit cavity in open but relatively restricted communication with the interior of the drum and receiving the ends of both said drain pipe and said tube.

2. The improvement herein described comprising a boiler drum with its steam outlet and a Water exit tube, the latter leading from the bottom of the drum, in combination with a steam purifier positioned within said drum and connected to said outlet, a drainpipe leading from said purifier toward the bottom of the drum and terminating above the open end of said exit tube, and a suitably perforated open bottomed box resting upon the bottom of said drum, covering said exit tube and receiving the lower end of said drain pipe.

3. The improvement herein described comprising a boiler drum with its steam outlet and a water exit tub-e, the latter leading from the bottom of the drum. in combination with a steam purifier positioned within said drum and connected to said outlet, a drainpipe leading from said purifier toward the bottom of the drum and terminating above the open end of said exit tube, and a suitably perforated open bottomed box removably positioned upon the bottom of said drum, covering said exit tube and receiving the the lower end of said drain pipe.

4. The improvement herein described compris'mg a boiler drum with its steam outlet and water exit tubes, the latter leading from the bottom of the drum, in combination with a steam purifier positioned within said drum and connected to said outlet, a drainpipe leading from said purifier toward the bottom of the drum and terminating above the open ends of said exit tubes, and a suitably perforated open bottomed box resting upon the bottom of said drum, covering a plurality of said exit tubes and through ill its top receiving the lower end of said drain 20

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