US909103A - Turbine. - Google Patents

Description

R. K. MORGOM & A. JUDE.

TURBINE. APPLICATION FILED JUNE? 13, 1908.

Patented Jan. 5, 1909.

" 2 SHEETS-SHEET 1.

Mmmsm R. K. MOROOM & A. JUDE.

TURBINE.

APPLICATION FILED JUNE 13, 1908.

Patented Jan. 5, 1909.

2 SHEETS-SHEET 2.

UNrtrED STATES PATENT OFFICE.

REGINALD KEBLE MORCOM AND ALEXANDER JUDE, OF BIRMINGHAM, ENGLAND, ASSIGNORS TO BELLISS & MOBCOM LIMITED, OF BIRMINGHAM, ENGLAND.

T'URB INE Specification 0: Letters ratent.

Patented Jan. 5,1909.

To all whom it may concern:

Be it known that we, REGINALD KEBLE MoacoM and ALEXANDER Jenn, subjects of the King of Great Britain, residing at Led sam Street Works, Birmingham, in the county of Warwick, England, have invented new and useful Improvements in Turbines, of which the following is a specification.

This invention relates to an improved design of turbine to be operated by expansive fluid in-Which, by a new combination of known elements, the energy of high pressure steam can be renderedmechanically available in a I more economical .manner than hitherto and the invention comprises devices adapted to facilitate the adjustment of Y portions of the turbine sub ect to wear and tear so as to maintain, throughout the working life of the turbine, those pressure conditions on which eflicient action depend;

The combination referred to is that of one or more vane-carrying wheels of relatively large diameter for the impulse'action of the fluid in the initial or earlystages of its expansion and a drum on drums for the later and terminalstages of the expansionfor the further impulse action of the same fluid when,with the smaller pressure, the velocity of exit from the stator guide-blades less and the volume is correspondingly greater.

Among other advantages, the impulse type of action has the merit that the static pressure of the fluid does not undergo any change during its passage between any one set 0 vanes so that the displacing eiiect on the rotor due to fluid-action on the vanes is derived only from the dynamic action by virtue of which the rotor is driven. On this account the axial displacing force on an unpulse-driven rotor will be relatively small and permit of the employment of a comparatively small balancing-disk or dummy-piston.

A further advantage belonging to the impulse-type of action is? that leakage of fluid occurs only between the surface of the rotor and the inner edge of the diaphragm or partition-of the stator which carries the guideblades and not between the stator and the outer extremity of the vanes as in turbines of the pressure operating type.- Accordingly, by the adoption of the impulseaction throughout the entire flow, the leakage areas will be minimized as well as the axial displacing force. But the adoption of the impulse-type involves a higher velocity-of vane than would be requisite with an alternative type of action. This requirement is conveniently provided for by'the-well known use of wneels of large diameter for the initial and early stages of the expansion but, inasmuch as the employment of such wheels, in the later stages of the expansion when the volume of the fluid to be dealt with is so much greater, is cumbersome and costly and causes much loss by disk-friction, we have found that with a drum-built rotorwith an increased number of expansion steps, to'keep down the velocity of issue from any one set of ide-blades, a much more economical ef feet will be produced.

A drum-built rotor of impulse-type will, as compared with a wheel-rotor of the same type, have a larger circumference of leakage between the rotor and the inner edges of the partitions of the stator. Accordingly, to compensate for this inherent disadvantage we provide, as a portion of this invention, special clearance-adjusting "devices at those portions of the turbine and as the purpose of the invention is to permanently maintain the necessary pressures at all parts of the turbine for economic andefficient working, leakageradjusting' devices will be required at all parts where leakage. can occur as will presently be described. To balance the much mitigated pre'ssure, which will be'exe erted on the rotor under the above circumstances, we adopt a revolving idle pistondisk but, in order that one of small area and diameter may suflice for the urpose, We

subject it to a very considerab e diil'erence of pressure on its two faces.

1n the accompanying drawings :-.Figure 1 is a half longitudinal section of aturbine showing a double-wheela'nd drum combination of rotor and a single balancing piston. Fig. 2 is a half longitudinal section of a modification in which a single wheel is combined with the drum and a diderential balancin piston is employed. Fig. 3 is a longitudindl section of a portion of the stator and a portion of a balancing piston or of the rotor shaft. Fig. 4 1s a ongitudinal section of a portion of the stator and a portion of a bal ancingpiston. Fl". 5 is a transverse section corresponding to Big. 4. Fig. 6 is a longitudinal section through a portion of the stator and of the rotor drum showing-a guide-blade'carrying partition in cross-section; Fig-.- 7 is a view similar to Fig. 6 but showing a modification. Fig. 8 is a longitudinal section of a portion of the stator and of another portion of the rotor drum, the guideblade carrying partitions being likewise shownin cross-section.

Referring to Fig. 1, which is to be regarded as a representative exdmple, a. and a. are

"of the wheel a.

wheel-portions of the rotor by means of which the steam undergoes two stages of expansion, these being fo lowed by a series'of expansions carried out. in the drum-portions b t b of the rotor.

By adopting such conditions that the fluid, in flowing from the supply passage. 0 to the compartment d, undergoes a fall of pressure and corresponding acquirement of velocity-energy which is utilized in assing the 'double, seriesof v'anes of the w eel a without further alteration-0f static pressure in its progress past the vanes thereof, there will be the same fluid-pressure on both sides If corresponding conditions occur in respect to the flow from the compartment d to the compartment 6 and passage through the double series of vanes of the wheel a the pressures will be alike also on bothsides of the Wheel a. Thus by the two-foldexpansion the ressure will be very considerably reduced wit out incurring much thrust on the rotor in an axial direction, such thrust as occurs being due to the fluidressures on the annular areas 6 and e o the bosses of the wheels 0, and a. Additional axial thrust from right to left will be due to the fluid pressure on the drum portions of the rotor, but by the combination of wheel and drum with impulse action on both as above described, the one-way axial-force on the rotor can be kept relatively small. To balance'this force by a-piston f of the least diameter, we sub ect one side thereof namely 9 to the initial pressure of the steam by the pipe connection it and the opposite side 2 to the terminal pressure of the steam by t e pipe k which, when a condenser is used, W1 l be less than the atmospheric pressure.

Fig. 2 shows a modified example in which there is only one wheel a but in which there is a differential balancing piston, having two diameters f and f, the side g of which is subjected to the initial fluid-pressurecon ducted through the pipe h as before, the space 9 which intervenes between g and g being, by the pipe 'h, subjected to an intermediate pressure which results from the expansion of the fluid from the supply passage 0 to the wheel a and the space g on the further side of the larger portion of the balancing piston being subjected to a still lower pressure which ma be the terminal pressure of the steam. In 2 the space g 18 shown connected by a pipe l t to a space in the stator between the portions b and b of the rotor Where the pressure is slightly greater than thatof the atmosphere. This will entail a somewhat larger balancing piston than that, if leakage occurs past the stuffing box I i, it will be of steam outwards in relatively small quantity, instead of air inwards which, by reason of a considerable difference of pressure, may be sufiicient to appreciably lmpair the vacuum. With this arrangement also any steam which leaks past the balancing piston will be. conducted by the pipe k to traverse the portions 5 and b of the rotor and do work.

Fig. 3 shows themethod of minimizing the leakage of steam past a balancing pistonf or a portion of the rotor shaft neither of which are exposed to extreme differences of pressure, consisting of a series of Ramslottom spring-rings It each of which, onrthe operating side thereof, carries an anti-friction nonseizing substance k, such as carbon, occupying a groove formed in the side of the ring.

Figs. 4 and 5 are two .views of a contriv ance for minimizing the leakage past a balancingiston or portion of the rotor shaft expose to greater differences of pressure,

. Fig. 4 being a part-longitudinal section and art-transverse section. In these Fig. 5 a figures, t mm are, interposed between the pistonporti0 n f of the rotor and the surrounding portion 0 of the stator, a plurality of rings, each composed of a plurality of segments m. Eachse ment is supported by one or more stud-brfitsn, which is adapted from the outside,even when the turbine is running, to either advance the segment towards the rotor or withdraw it. The steamjoint between the stator and the back of the segments m is effected "ry flanges m which fit into internal grooves 0 formed in the interior surface of the stator 0. 'l he joint between the adjacent segments of each ring is effected b means of an overlapping strip m which, be ore assembly, is secured to the end of one segment, the end of the adjacent segment being beveled, as indicated in dotted lines in Fig. 5, to facilitate insertion. Ihe segments may have a plain surface as represented by the outside rings in Fig. 4 or, as shown by the middle ring in that figure, they may he provided with deformalle segmental packing stri s m which are adapted to yield to a radial orce and which also, by the endish shaped and thereby adapted to be forced into closer proximity to the rotor by a deforming pressure which makes the angle still more obtuse. In Fig. 7 the segments p are of Y section one flange of which is adapted to be deformed, towards the surface of the rotor. In these the principle of the, adjustment resides in the capability of fiattenlng a dished surface to a greater or less degree. Fig. 8 shows an adjustable mounting of the plates p of the high pressure ortion b of the rotor drum where it isdesira le that a more exact adjustment and one also capable of being efi'ected from the exterior while the turbine is in operation, be employed. In this construction the adjustment of the periphery of the plates p towards or from the rotor is effected in a manner similar to that adopted nuts g in Figs. 4and 5. In this figure, g g are segmental blocks by which the plates p are secured, the blocks being carried on the ends of the stud bolts g g provided with looking We 0 aim: 1. A turbine for expansible fluids comprising a wheel, vanes carried thereon, a

stator, a partition wall in said stator extend-- ing inwards to a portion of the rotor of small diameter, means for minimizing leakage between the edge of the partition and the rotor, guide-blades fitted in an aperture in said partition arranged to direct the fluid on to the wheel-vanes and effect an impulse-action thereon without change of pressure while passing between the vanes, a drum, vanes carried by the drum, a partition wall in stator extending inwards towards'the drum surface, means for minimizing the leakage between the edge of the partition wall and the drum surface and guide-blades fitted in an aperture in said partition arranged to direct the fluid on to the drum-vanes and effect an impulse-action thereon without change of pressure while passing between the vanes.

2. In a turbine, means for adjusting the clearance spaces between the stator and the 3. In a turbine, means for adjusting the the stator p clearance spaces between the stator and the periphery of a balancezpiston,compnsing segmental blocks in sai clearance spaces,

flanges on said blocks fitted in groovesv formed in the stator, stri s overlapping the butting ends of adjacent locks an adjusting bolts on which said blocks are mounted.

5. In aturbine, means for adjusting the clearancespaees' between the stator and the periphery of a balanceiston, comprising segmental blocks in sai clearance spaces, flanges on said blocks fitted in grooves formed in the stator, strips overlapping the butting ends ofadjacent blocks, adjustin bolts on which said blocks are mounted an deformable strips secured to said blocks on the surface presented towards the balancepiston.

6. In a turbine of the impulse type, means for adjustiin the clearance spaces between Iates and the low pressure portions of the rotor drum, comprising deformable segments secured to the inner borders of the stator lates.

7. In a tur me of the. impulse type, means for adjusting the clearance spaces between the stator plates and the low-pressure portions of the rotor drum, comprising deformable segments'formed with an overhanging dished flange secured to the inner borders of the stator plates.

8. In a turbine of the impulse type, means for adjusting the clearance spaces between the stator plates and the high-pressure'portions of the rotor drum, comprising seg mental blocks in which said plates are carried and adjusting bolts on which said blocks are mounted.

9. In a turbine of the impulse type, means for adjusting the clearance spaces between the stator plates and the high-pressure portions of the rotor-drum, comprising segmental blocks on which said plates are carried, flanges on said blocks fitted in grooves formed in the stator and adjusting bolts on which said blocks are mounted.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

REGINALD KEBLE MORCOM.' ,ALEXANDER JUDE.

Witnesses ERNEST BARKER, ALBERT HALSTEAD.

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