USRE7331E - Improvement in steam-generators - Google Patents

Description

2 SheetsSheet 1.

air. McLAUTHLIN.

STEAM GENERATOR.

No. 7,331. Reis sued 0012.3,1876.

sea: I I

I 2 Sheets-411M122; G.- T. McLA'UTHLIN. STEAM: GENERATOR.

Raissuei. Oct. 3, 1876.

UNITED STATES PATENT FFICE.

GEORGE T. MGLAUTHLIN, OF BOSTON, MASSAUHUSETTS.

IMPROVEMENT IN' STEAM=GENE RATORS.

Specification forming part of Letters PatentNo. 166,393, dated August 3, 1875 reissue No. L331, dated October 3, 1376; application filed September 18, 1876. I

To all whom it may concern:

- Be it known that I, GEORGE T. \IoLAUtrn- LIN, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Steam-Generators; and I do hereby declare that the following, taken in connection with the drawings, which accompany and form part of this specification, is a description of my invention, sufficient to enable those skilled in the art to practice it.

My invention relates to certain details ot' construction of stealngenera'tors of that class in which a series of water-tubes depend from the crown-sheet of a water and. steam-chainber-into the fire-box or chamber, each tube having within it, or inclosing, an inner tube to efi'ect a circulation, and secure a thin sheet or tube of water in contact with the inner side- 5, a plan or topview of one of the tube-hold ers; Fig. 6, an interior top view of the tubeclosing. plug, andFig. 7 a section of a modified form of outer and inner tube.

at denotes the brick-Work or casing of the furnace; b-,.'the gates; c, the fire -"pot and chamber; .d, the chimney orflu'e.

In the. upper-partot' the chamber 0 is lo catedth'e main water and steam chamber 9, havingaside casing, it, (around which the flames and. othervolatile products ofcombus tion course in their passage from the fire-pot to the chimney,) and upper and lower crownsheets The: cylinder rests'upon suitable supports ,l projecting from the furnace-wall, and the upper and lower sheets i k are con,- nected by a series of ties, in 'n, and boltso p, each pair mm. of the ties being connected to the upper sheet'by an eyebolt, o,'the head of which is fastened to the ties by a pin, q, and the screw-threaded end of which ,is fitted into the sheet. and is further secured by a nut, r,

and to the lower sheet by a similar eyebolt, 11, pin 8, and nut t.

Each of the ties is made of thin strap-iron, and by thus giving to each large superiicles (or by any means exposing sufii'cient surfaces) I secure, in combination with theboilcr-braccs, surfaces against which the water in the steamroolnis attracted, and down which it drips, the

distributing of these metal surfaces throughout the chamber thus attracting or afi'ording lodging-surfaces for all particles of water, and

tending to keep the steam dry.

The ties are all of equal lenglh, so that when they, or any of theuu-arc removed (by knocking out their pins) for access to the chain her, they may be interchangeably replaced, v

each fitting in any place, and

to any of the bolts. r

These flat-iron or strap-iron ties, thickly in terspersed, making thcinof equal length and interchangeable, and connecting the slic or heads of the cylinder by the straps, bolts, nuts, and pins, are features of my invention. From the crown-sheet depend the watertubes u. the fire-chamber, and hangs free therein, being secured in'place only by its cgnnection at the top with the crown-sheet. Each is con'- nected to the crown-sheet by a screw-thread,

'17, near its upper end, working in a nut-thread in the sheet. Each opens into the'cliamber g, and the open end to of each-projects a short distance above the inner surface of the sheet, as seen in Figs 1 and 4, so that sediment and and not be drawn into the tubes. 1

calcareous deposits shall lodge upon the sheet,

the plug d Fig. 4, and withiu each tn another central tube, y, the-bottom oi b ll! rests upon centering and supporting rings'z, projecting from the plug d the tube a, or

the tube 31, leaving a free water-passage from Each tube extends down well into,

' leaving tube to tube, as shown at a while the upper part is'centered by the tube-holder having springs b extending from an encompassing ring, 0

The upper end of each tubeg] projects some distance above the tube 1:, so as to effect a circulation 05 solid water down tubes 3 the steam generated between the inner tube and' the outer tube, parting from the water when it leaves the mouth of the large tube, spreading into the space between the projecting tubes g ,'and passing up into the steam-space, the solid water to return through tube y. i v

Each circulating-tube 3 maybe removed from the tube u, either through the top thereof into the steam-room, or through the bottom into, the fire-pot, (the plug being in the latter case first ren1oved,) and, in like manner, the circulating-tu e may be replaced or put into the outer tube.

'When the tube y is entered at the top of the tube it, its bottom self-centers, or is guidedby the radial wings z, and in entering from the bottom of the ring and its wings, are used to centrally locate the upper end, while the: lower end is centrally located by securi'ngthe plug in place, (if the plug be made with the guide-wings,) or by any other'suitable guiding devices.

The tube a, 1s a peripherally screw-threaded cap or head, the.screw-thread of which enters a Q nut-thread in the lower end of the tube.

At the center of the plug isa safety-valve,

c said .valve being attached to the outer end ofa pin, f at whose inner end is a nut, 9

the stress of a' suitable spring, k acting upon this nut, closing the valve. The power of this spring is such that the pressure of the steam upon the valve compresses the spring and opens the valve when the pressure of the steam exceeds the limit of working pressure or approaches an unsafe pressure.

The valve-seat is on a screw-threaded ring, 11 that screws into the plug. 7 v The spring 7L is a coiled spring, mill is cast in, shape as shown in the drawing. The spring k s 'iring-stand m and the seat-ring i are cast in one piece.

The space between the seatring and valy'e at its periphery is arranged for the purpose of receiving the end of a forked lever, by which the valves can be opened, when desired, to drain the tubes, these valves serving the double purpose of safety-valves and tubedrainers.

,Instead of such construction, the inner tube, or part of it, may be castin the form of i a tubular coiled spring, or it may be made of flat metal bars, coiled so as to form a tube, in either case having a cross-bar at its lower end, connecting by a central screw, with a head or'cap, the edge of which abuts against the end of the main tube, the abutting edges being ground to make a tight joint. The upplug (1 that closes the bottom of each When the pressure otthe steam exceeds thethe steam presses.

limit of working-pressure, down the cap, (the coils of the inner tube opening,) and the water escapes upon and extingnishes the fire. This modification is represented at Fig. 7.

The inner tube is so made that there is no space between the adjacent coils to disturb the circulation, while the pressure of the steam (below or near a safety-pressure,) forces down the cap by opening the spring.

To drain the water from the tubes, the cap may have projecting lugs k by prying over which the cap may be forced down slightly, so -that the water can escape, this arrangement of the tube and ca-p'attbrding the double purpose of safety-valve and draining-valve.

Over the tubes a, through the water and steam-room, and its systemof ties, a blow-off pipe, 1 extends, with suitable branches m haying vertical arms a, which pass down close to the surface of the crownsheet. Their open ends are between nests of tubes, and, in blowingo'tf, any deposits upon the sheet arev drawn into the pipes and blown into the atmosphere, thus preventing deposits from accumulating, and from rc-entering the water-tubes.

By proper use of this blow-off mechanism the internal surfaces of the boiler, its crownsheet, and the tubes, are all kept clean and free from injurious deposits, as the blow-off pipes take the dirt and deposits t om the only lodging-place they have, and be ore they become incrustations.

By my arrangement and construction of the tubes the fire-pot may be entered, and each plug, or any particular plug, may be withdrawn from each or any one of the tubes to, and the inner tubes, each or either, or all of them, may.

be removed, the same being also the case with the main tubes. Inlike manner each pair, or any one or more of the pairs, of ties may be removed from the steam-room, and any one or more of the circulating-tubes may be removed for examination thereof, or for examination of the main tubes. Thus the whole boiler and every part of it are alike accessible for repairs, examination, or cleaning, and the boiler may be taken to pieces or put together with the greatest ease, and with ordinary skilled labor, and in a very short time.

The feed-pipe m or distributor for supplying the boiler or generator with water extends across the cylinder, and is perforated with a number of small holes, s'o arrangedas to discharge the water upward. With a supplypipe sopertbrated there is no liability of burst-' ing the gcneratorby the introduction of water, should the water in thegenerator be exhausted, for the water discharged from. the distributor in a number of small streams and upward is quickly t'ormed into steam. By inserting the plug 1! within the depending tube I afford an mean I s additional means of safety. The screw-thread cut in the end of the tube weakens it at that point, and pressure beyond the safety-point would allow "the tube, it not being held externally, to stretch out. This would not be the case with an encircling-cap.

I have described that the small safety-valves at the ends of the depending tubes open when the pressure of the steam exceeds the limit of working pressure, or approaches an unsafe pressure. The working pressure of the steam is set or regulated by the ordinary safetyvalve; and these small valves at vthe ends of the tubes are set so that they will not blow off until above the working pressure then, should the regular safety-valve become inoperative, these small valves yield one by one, according to the pressure of steam required to overcome their springs, and they then discharge the water on the fire, and in this way the failure of the safety-valve to act does not result in de-' stroying the boiler; and'further, if the re ular safety-valve is overloaded to such a degreeas might burst the boiler, the smhli valves, being set at a pressure below unsafe gressure, will blow oil, and extinguish the re. i I claimx 1. The removable ring 0 and its springs b, combined with themain depending and the circulating tubes for centering and holding the upper end of the circulating-tube, substantially as set forth.

2. The? main depending tube u, connected with the crown-sheet by means of screwthreads, {as set forth, and the circulating-tube y withinlthe main tube, combined with the removable centering dcviees, substantially'as described, for centering the circuIatingFtu at bottom and top, as set forth.

3. The outer tube u,'the inclined projections g z, and the inner tube 3 arranged, with relation to each other, substantially as described,

and so that the lower end of the inner tube is centered automatically, and its end left'unobstructed for the passage of water, as set forth. 4. The outer tube 10, provided with the re movable plug, combined with the inner tube .and removable centering mechanismaand arranged, with relation to, thesteam-chamber and fire-box, so that theinner tube may be removed from the top or the bottom of the outer tube, substantially as described.

5. The combination, with the outer and inner tube, of the safety-valve, arranged.te discharge the water'on the fire in the tire-box, v

substantially as described."

- 6. The combination, with the sheets or heads of'a steam-generator, of the'removable ties of equal lengths, and adiustablecyebolts, the ties being interchangeable, as and for the purpose set .forth.

7. The vertical steam and water cylinder, arranged above the flre-box,'an d forming no 'part' thereof, and having an open annular and the tubes at and y, suspended and space about the cylinder for the passageof the heat and products of combustion, the entire cylinder having an equal exposure, or

nearly so, on all sides, substantially as set forth. I

GEO. T. MGLAUTHLIN.

Witnesses i G. W. GREGORY, W. J. PRATT.

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