US2122235A - Turbine - Google Patents

Description

June 28, 1938.

L. D. MILLARD TURBINE Filed Nov. 20,, 1937 5 Sheets-Sheet 1 June 28, 1938. L. D. MILLARD 2,122,235

TURBINE Filed Nov. 20, 1937 5 Sheets-Sheet 2 2 June 28, 1938. D. MILLARD TURBINE Filed Nov. 20, 1937 5 Sheets-Sheet 3 462- IIIIIIIIIEIIIIIII 4 45 :IIIIIIIIIIIIIII June 28, 1938. D 2,122,235

TURBINE Filed Nov. 20, 1937 5 Sheets-Sheet 5 Z Mi 11111111 Patented June 28, 1938 UNITED STATES PATENT OFFiCE Murray Iron Works Company, Burlington,

Iowa, a corporation of Iowa Application November 20, 1937, Serial No. 175,707

Claims.

My invention relates to improvements in turbines.

In general, a 360 arc of steam admission, through a steam turbine wheel is desirable, because this makes for maximum efficiency, due to reduction of windage losses caused by idle blades. For a given steam flow, the blade length decreases as the arc of admission increases thus simplifying the mechanical problems connected with blade and rotor construction. However, the 360 arc of steam admission through the steam turbine wheel is not ordinarily employed in small turbines due to certain mechanical problems which arise. Practical considerations dictated a widely used construction, wherein the casing is split on the horizontal center line of the casing, with all steam and exhaust pipe connections in the lower half of the casing, constituting the base. This allows dismantling without breaking pipe connections or disturbing alignment. While this arrangement is not always followed, users preference for such an arrangement has forced its almostuniversal use for small turbines.

A serious objection to this construction wherein the casing is split on the center line of the easing is the fact that only a relatively small are of steam admission to the wheel or rotor is possible. It is frequently found impracticable to get the required quantity of steam through the wheel without using an unnecessarily large wheel or large nozzles and blade heights. Hand valves for partial load and overload conditions are desirable, but where the arc of admission is used, as indicated, only a small space is available. This makes it necessary to restrict the number of hand valves or makes them inaccessible, if provided. I

The present invention provides a construction which retains the desirable features of a casing split on the horizontal center line, with all pipe connections in the lower casing section or base, and at the same time overcomes the objectionable features of such a casing. In accordance with the present invention, the turbine casing is so constructed that bearings for the shaft of the wheel or rotor are arranged centrally of the casing, but are not disturbed when it is desired to have access to the interior of the turbine casing. The access to the interior of the turbine casing is afforded by a split in the turbine casing well above the center line, the upper portion of the casing then serving as a removable cover. This arrangement provides the lower portion of the turbine casing extending through a considerably greater distance than 180, thus increasing the arc of steam admission, which now extends for more than 180, to a considerable extent, as desired. This increase in the length of the arc of admission can be utilized in either of two ways. It will permit of adding more nozzles to increase the steam capacity whereby the output of a given size turbine can be greatly increased. Further, it will permit of using more nozzles of a smaller diameter, thereby producing a turbine of greater efficiency. The increased length of the arc of admission also makes more room for hand valves for hand controlled nozzles, where operating conditions are such that these hand valves are needed. The improved construction also allows the cover to be small and light and easily removable for inspection within the interior of the turbine casing without disturbing any other part of the turbine and this cover can also be readily sealed to the base by a gasket joint. A further advantage in the new construction is that with the split between the cover and the lower casing section or base being arranged well above the true center line of the turbine casing, absolute center line support for the turbine casing is obtainable, which is essential if the turbine is to A be free from misalignments, due tothe expansion of the casing by the heat of the steam or the like. In addition to these advantages, the improved construction greatly simplifies the machine work required for the turbine casing. A further advantage of the improved construction is that the wheel, shaft and carbon gland rings, upon the removal of the cap or upper casing section may be readily separated from the lower casing section when desired. A further advantage of the improved construction is the excellent provision it makes for controlled steam flow through the wheel and from the wheel into the exhaust.

In the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a plan view of a turbine embodying my invention,

Figure 2 is a central vertical longitudinal section taken on line 2- -2 of Figure 1,

Figure 3 is an end elevation of the turbine, viewed from the exhaust end,

Figure 4 is a transverse section taken generally on line 44 of Figure 2,

Figure 5 is an exploded side elevation of a turbine and the parts in section,

Figure 6 is a horizontal section taken on line 6-6 of Figure 3,

Figure '7 is an inner side elevation of the nozzle carrying chamber, and,

Figure 8 is a section taken on line 88 of Figure 7, the same being flattened or distorted.

In accordance with the present invention, the numeral I designates a turbine casing as a whole, which embodies a lower casing section I I, having an end or head I2. The casing I0 is generally circular in the plane of rotation of the wheel to be described. The closed end I2 is preferable integral with the lower casing section II and has a U-shaped opening or recess I 3 formed therein, as shown. The bearing I4 embodies a lower part I5 including an oil well, and this lower part is rigidly attached to the lower part of the gland case, to be described later, by spaced webs or walls I6, preferably formed integral with these parts. The bearing M includes an upper part I1, which is detachably secured to the lower part I5 by bolts I 8 or the like.

The lower casing section II is attached to a base I9 by a dowel which is a sliding fit in the closed end or head l2. This allows the casing to expand radially from the center line of the turbine but does not allow it to move horizontally. This base is rigidly attached to standards 2! having feet 22. The upper ends of these standards are rigidly secured to horizontal braces 23, preferably formed integral with the upper portion of the end or head I2. These braces being hollow inside serve as excellent openings for carrying the exhaust steam away from the wheel. Since the bearing M is rigidly mounted upon this end or head I2, thebraces 23 and associated ele ments serve to stiffen the end or head against any possible displacement.

The end of the casing section II opposite the closed end or head I2 will be designated by the numeral 25. This end 26 has a vertically arranged U-shaped opening or recess 28, corresponding to the recess I3. The recesses I 3 and 28 are oppositely arranged, are in alignment, and pass through the tops of the ends or heads I2 and as shown. The end or head 25 also has a circumferential opening 24 in its face through which is inserted an arcuate steam admission or nozzle carrying chamber 29. This nozzle carrying chamber, by means of a flange, is fastened securely to the end 26 by bolts 25 and 2'! or the like. This flange covers and seals the opening 24. As better shown in Figures 4 and '7, the nozzle carrying chamber 29 extends circumferentially throughout the casing beyond the center line and for more than 180. The chamber 29 is provided with the nozzles 29, Figure 7, as is well known in the turbine art, and these nozzles supply the steam to the wheel to rotate the same. The nozzle carrying chamber 29 is curved or arcuate and is provided at suitably spaced points with hand wheels 30, Figure 4, which are employed to open or close valves to control the passage of steam from the chamber 29 to selected nozzles or groups of nozzles 3|, as is well known in the art. At this point, particular attention is called to the fact that the nozzle carrying chamber 29 extends throughout more than 180, and, as shown in Figures 4 and '7, its opposite ends extend well above the center line of the casing.

The numeral 3I designates a bearing, arranged opposite to and corresponding with the bearing I l. Bearing 3| includes a lower portion 32 having an oil well and this lower portion is rigidly attached to the lower half of the gland case, to be discussed later, by webs33. The lower portion 32 is also rigidly attached, at 34, with a vertical support 35. The bearing 3I also includes an upper portion 36, which is detachably secured to the lower portion 32 by bolts 31 or the like.

Steam is supplied to the casing through an inlet pipe 38, and enters the casing through a passage 39, Figure 8, in communication with chamber 29 and the supply of steam is controlled by a reciprocatory valve device 40, operated by a governor II. The steam is thus supplied in the proper amount to rotate the rotor at a desired speed.

After passing through the wheel, the steam discharges from the casing I0 through the exhaust pipe 42.

Rotatably mounted within the casing I0 is a wheel or rotor 43, rigidly mounted upon a horizontal shaft 44. This shaft is journaled in the bearings I4 and 3|. These bearings are split horizontally through their centers, with the upper portions I! and 36 removable, as explained, and the horizontal centers of these bearings are in alignment with the horizontal centers of the casing Ill. The numeral designates a gland, surrounding the shaft 44. This gland is split horizontally making a lower part which is rigidly attached to the lower part of the bearing I5 by Walls I6 as described before. This lower half 55 of the gland locates in the round part of the U- shaped opening I3, thus locating the gland and bearing on the center line of the casing. The lower part of the gland is flanged and secured to the end I2 by bolts 56 or the like. The gland 45 includes an upper part 51 which is detachably secured to the lower part 55 by bolts 53 or the like. This upper part of the gland 51 is also flanged and secured to the end I2 by bolts 41 or the like, thus scaling up the U-shaped opening. The top of this upper part terminates with a horizontal flange 46.

In a similar manner a gland 48 surrounds the shaft 44. This gland is split horizontally making a lower part 59 which is rigidly attached to the lower part of the bearing 32 by webs 33 as described before. This lower half of the gland 59 locates in the round part of the U-shaped opening 28, thus locating the gland and bearing on the center line of the casing and in line with the opposite gland and bearing. The lower part of the gland is flanged and secured to the end 25 by bolts or the like. The gland 48 includes an upper part 6| which is detachably secured to the lower part 59 by bolts 62 or the like. This upper part 6| is also flanged and secured to the end 25 by bolts 50 or the like, thus sealing up the U- shaped opening. The top of the upper part terminates with a horizontal flange 39. The gland 48 is clearly shown in Figure 4, and the gland 45 is similar to gland 48, as is obvious. It might be stated at this point that when the upper bearing parts I? and 36 are removed and the upper gland parts 51' and GI are removed, the shaft 44 and Wheel 43 are removable as a unit upwardly through the U-shaped openings I3 and 28. The glands 45 and 48 hold the usual packing rings 45a and 48a respectively.

The casing I0 is split horizontally a considerable distance above its center line, and the center line of the casing is at the center of the shaft 44, whereby the lower casing section II extends above the horizontal center line for a considerable distance, as explained. The splitting of the casing horizontally above the center line, as explained, provides an upper casing section or cap 5 I, having a horizontal flange 52, detachably connected with the horizontal flange 53 of the lower casing section by bolts 54. This horizontal flange 52 also fits over the horizontal flanges 46 and d9 of the upper portions of the gland cases 45 and 48. The assembled upper and lower casing sections constitute the entire casing H), as explained.

From the foregoing description, it is seen that by removing the top casing section or cover 5|, access may be had to the interior of the lower casing section, without in any way disturbing the nozzles, valves, glands, steam connections, or other parts ofthe turbine.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts, may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a turbine, a casing having a center line and split horizontally a considerable distance above the center line to provide a lower casing section extending throughout considerably more than 180 and an upper removable casing section, an arcuate nozzle chamber carried by the lower casing section and extending about the center line of the casing for considerably more than 180, a shaft extending through the lower casing section at the center line of the casing, a wheel carried by the shaft and arranged within the casing, said lower casing section having means to permit of the upward movement of the shaft from within such lower casing section, means to prevent the discharge of steam from the lower casing section about the shaft, and bearings for the shaft and adapted to permit of the upward movement of such shaft.

2. In a turbine, a casing having a center line and split horizontally above the center line for a considerable distance for providing a lower casing section extending considerably beyond 180 and a removable upper casing section, the lower casing section having openings formed in its ends, the upper ends of the openings being open, an arcuate nozzle chamber carried by the casing and concentric with the center line of the casing and extending considerably beyond 180, bearings arranged exteriorly of the casing and. concentric with its center line, a shaft held within the bearings at the center line of the casing and passing through the openings in the ends of the casing, and gland and bearing housings removably mounted within the openings in the ends of the casing and receiving the shaft.

3. In a turbine, a casing having a center line and split horizontally considerably above the center line for affording a relatively large lower casing section and a relatively small removable upper casing section, the relatively large lower casing section having ends provided with substantially vertical U-shaped openings passing through their tops, an arcuate nozzle chamber connected with the lower casing section in substantial concentric relation thereto and extending considerably beyond 180, bearings arranged in alignment With the center line of the casing, a shaft held within the bearings and extending through the casing, a wheel mounted upon the shaft and arranged within the casing, glands arranged upon opposite sides of the wheel and receiving the shaft therethrough, said glands being movable in a vertical direction through the substantially vertical U-shaped openings, and flanges secured to the glands and covering the U-shaped openings and attached to the ends of the casing.

4. In a turbine, a casing having a center line and split horizontally considerably above the center line for providing a relatively large lower casing section and a relatively small upper casing section, the lower casing section having ends provided with U -shaped openings which pass through the tops of the ends, stationary bearings arranged exteriorly of the casing and split horizontally through their center line and through the center line of the casing, said bearings including upper removable parts, a shaft held within the bearings and passing through the center line of the casing, a wheel within the casing and mounted upon the shaft, an arcuate nozzle chamber for the lower casing section and extending a considerable distance above the center line of the casing, glands arranged upon opposite sides of the wheel and having flanges, said glands being movable downwardly through the U-shaped openings, and means to attach the flanges to the ends of the casing.

5. A casing having a center line, said casing having opposite ends, said casing being split gen erally horizontally for a considerable distance above its center line, said split extending through the opposite ends of the casing thereby providing a body portion extending for considerably more than 180 and a removable cap, a steam chamber separate from the cap and carried by one end of the body portion and extending for considerably more than 189, nozzles connected with the steam chamber and aranged in a curved group and extending for more than and arranged within the body portion, valves carried by said end to control the passage of steam from the steam chamber to certain of the nozzles, said valves being accessible fromthe exterior of the body portion, bearings separate from the cap and having their center lines in alignment with the center line of the casing, a shaft held within the bearings, and a wheel within the casing and carried by the shaft.

6. In a steam turbine, a casing having a cen ter line, said casing having opposite ends and being split generally horizontally for a considerable distance above the center line, said split dividing the casing into a body portion extending for considerably more than and a removable cap, said removable cap constituting a portion of the periphery of the casing, a curved group of nozzles carried by one end of the body portion and separate from the cap, the curved group extending circumferentially for a considerably greater distance than is obtainable with the same casing split horizontally through its center and the group attached to the lower casing section and separate from the cover, bearings having their center lines in alignment with the center line of the casing, a shaft held within the bearings, and a wheel within the casing and carried by the shaft.

'7. In a steam turbine, a casing having a center line, said casing being split generally horizontally for a considerable distance above its center line for dividing the casing into a body portion extending for considerably more than 180 and a removable cover, said body portion embodying ends having generally vertical openings which are open at their tops, a curved group of nozzles carried by the body portion and separate from the cap, bearings separate from the cap and having their centers in alignment with the center line of the casing, a shaft extending through the casing and held within the bearings, glands receiving the shaft and removably mounted within the generally vertical openings, and a wheel within the casing carried by the shaft.

8. In a turbine, a casing having a periphery and ends, said casing being split generally horizontally for a considerable distance above its center line for dividing the casing into a body portion extending for considerably more than 180 and a removable cap, the cap constituting a portion of the periphery of the casing, a curved group of nozzles carried by the body portion and separate from the cap and extending circumferentially for a considerably greater distance than is obtainable if the casing Were split horizontally through its center line, bearings having their center lines in alignment with the center line of the casing, said bearings having parts detachable with relation to the casing, a shaft extending through the center line of the casing and held within the bearings, a wheel arranged within the casing and carried by the shaft, means to prevent the escape of fluid pressure from the body portion about the shaft and to permit of the upward movement of the shaft, the arrangement being such that when the cap is removed and the detachable parts of the bearings released that the shaft and wheel may be removed in an upward direction from the body portion without disturbing the nozzles.

9. In a turbine, a casing having a periphery and ends, said casing being split generally horizontally for a considerable distance above its center line for dividing the casing into a body portion extending for considerably more than 180 and a removable cap, the cap constituting a portion of the periphery of the casing and affording a top opening when removed, the body portion being provided in its ends with upstanding openings, a curved group of nozzles carried by the body portion and separate from the cap and extending circumferentially for a considerably greater distance than is obtainable if the casing was split horizontally through its center, bearings having their center lines in alignment with the center line of the casing, said bearings having releasable parts, a shaft extending through the center line of the casing and said upstanding opening and held within the bearings, means to prevent the escape of fluid pressure through the upstanding openings and a wheel arranged within the casing and carried by the shaft, the arrangement being such that when the cap is removed and the releasable parts of the bearings released that the wheel and shaft may be removed from the body portion without disturbing the nozzles.

10. In a turbine, a casing having a periphery and ends, said casing embodying a body portion extending for considerably more than 180 and a removable cap, the cap constituting a portion of the periphery and affording an opening in the periphery when removed, the body portion being provided in its ends with generally radial openings, a curved group of nozzles carried by the body portion and separate from the cap and extending circumferentially for a considerably greater distance than is obtainable if the body portion extended for only 180, bearings having their center lines in alignment with the center line of the casing, said bearings having releasable parts, a shaft extending through the center line of the casing and through the generally radial openings and held within the bearings, and a wheel arranged within the casing and carried by the shaft, the arrangement being such that when the cap is removed and the releasable parts of the bearings released that the wheel may be removed from within the body portion without disturbing the nozzles.

11. In a turbine, a casing having a periphery and ends, said casing embodying a body portion extending considerably beyond 180 above the center line of the casing and a removable cap for providing an upper opening in the periphery when the cap is removed, said body portion being provided in its ends with generally vertical openings, a curved group of nozzles discharging into the body portion and separate from the cap and extending circumferentially for a considerably greater distance than is obtainable if the body portion extended for only 180, generally horizontally split bearings having their center lines in alignment with the center line of the casing, a shaft extending through the center line of the casing and the generally vertical openings and held within the bearings, and a wheel within the casing and carried by the shaft, the arrangement being such that the wheel and shaft may be removed from in the body portion without disturbing the nozzles or the lower portions of the bearings.

12. In a turbine, a casing having a periphery and ends, said casing embodying a body portion extending considerably beyond 180 above the center line of the casing and a removable cap for providing an upper opening in the periphery, said body portion having generally vertical openings in its ends, a curved group of nozzles discharging into the body portion and separate from the cap and extending circumferentially for a considerably greater distance than is obtainable if the body portion extended for only 180, generally horizontally split bearings having their center lines in alignment with the center line of the casing, said bearings embodying upper and lower parts, generally horizontally split glands arranged within the generally vertical openings and embodying upper and lower parts, a shaft extending through the center line of the casing and through the glands and held Within the bearings, and a wheel within the casing and carried by the shaft, the arrangement being such that the wheel and shaft may be removed from within the casing without disturbing the connections of the nozzles and the adjustments of the lower parts of the bearings and glands.

13. In a turbine, a casing having a periphery and ends, said casing embodying a body portion extending considerably beyond 180 above the center line of the casing and a removable cap for providing an opening in the periphery, said body portion having openings in its ends extending to the top of the body portion, a group of nozzles discharging into the body portion and separate from the cap, generally horizontally split bearings having their center lines in alignment with the center line of the casing, the bearings having upper and lower parts, glands arranged within the openings in said ends and split generally horizontally to provide upper and lower parts, a shaft extending through the casing and through the glands and held within the bearings, and a wheel within the casing and mounted upon the shaft, the arrangement being such that the wheel and shaft may be removed from within the body portion without separating the wheel and shaft and without disturbing the connections of the nozzles or the adjustments of the lower parts of the bearings and glands.

14. In a turbine, a casing including a body portion and a removable cap, the body portion having ends provided with openings extending through the top thereof, horizontally split glands arranged within the openings and embodying upper and lower parts, horizontally split bearings arranged exteriorly of the body portion and embodying upper and lower parts, means rigidly connecting the lower part of each gland with the lower part of the adjacent bearing, a shaft extending through the casing and arranged within the glands and bearings, a wheel within the easing and mounted upon the shaft, and means to supply fluid pressure into the casing to rotate the wheel.

15. In a turbine, a casing having a center line and split horizontally a considerable distance above the center line for affording a body portion and a removable cap, a wheel within the casing, a shaft carrying the wheel, said body portion having means to receive the shaft and to permit of the removal of the shaft and wheel as a unit from within the body portion by upward movement of the shaft, means to prevent the escape of fluid pressure from within the body portion about the shaft, bearing means for the shaft, and means separate from the cap for supplying fluid pressure to the wheel, said fluid pressure supplying means extending considerably beyond 180".

LOREN D. MILLARD.

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