US1678066A - Turbine-cooling means - Google Patents

Description

July 24, 1928. 1,678,066

. c. J. LAMB TURBINE COOLING MEANS Filed Nov. 4', 1935 INVENTOR ATTORNEY CJ. Lamb periods,

Patented July 24, 1928.

nnrrsn STATES I 1,678,066 PATENT OFFICE.

CARL J". LAMB, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TURBINE-COOLING MEANS.

Application filed November My invention relates to elastic fluid turbines, more particularly to means for maintaining an even distribution of heat throughout the mass of the turbine rotor during idle and has for its object the provision of apparatus of the character designated which shall be simple of design, easy of manufacture and application, and efficient of operation.

Apparatus embodying features of my invention is illustrated in the accompanying drawing,'forming a part of this specilica tion, in which the single figure is a view, partly in section, which illustrates an elastic fluid turbine having my improved apparatus applied thereto.

In the operation of power plants, as is well known, there is ordinarily a variation of power demand in a days operation. During certain hours of the day more power units must be put in'service to supply the power demand than during other hours. It follows therefore that in a days operation one or more units are operated for a part time only and are shut down the other part of the time.

Where elastic fluid turbines are employed as prime movers under the circun'istances mentioned, difficulties have been encountered due to the unequal distribution of heat within the turbine casing during idle periods. lVhcn the turbine is in operation, its rotor, or portions thereof, assume the temperature of the motive fluid, which may be upwards of 700 F. When the turbine is shut down and remains idle for several hours the temperature within the casing becomes greater at the top than at the bottom and the idle rotor cools off to a greater extent at the bottom than at the top. The lower part of the rotor being cooler than the upper part, it contracts to a greater degree so that the rotor is caused to bow or bend somewhat due to the differences in temperature. If now the turbine is again started, it will be found to be decidedly out of balance and rubbing of the parts is liable to occur if it is brought up to its designed speed before the heat of the rotor has again become evenly distributed throughout its mass.

The unequal heating of the turbine casing has the same effect, the turbine being bowed upwardly due to the greater expansion on the upper side. The result is that the blade rows become eccentric to the axis of the by gravity thereto.

4, 1925. Serial No. 66,830.

turbine. As the high spots of the rotor pass the high spots of the blades, rubbing quickly takes place.

Various expedients have been resorted to in order to overcome the before-mentioned difficulty; that most commonly employed being the provision of a separate motor with suitable gearing to keep the rotor of the idle turbine slowly rotating during its idle periods. This and other expedients known to me are obviously expensive and cumbersome.

In accordance with my invention I have overcome the before-mentioned dilficulty by providing a circulation of liquid downwardly around the turbine rotor during idle periods. The liquid employed is preferably condensate and may be taken directly from the hot-well of the condenser and returned The liquid is introduced into the inte'riorof the turbine Casing in the upper part thereof in the form of a plurality of sprays. Inasmuch as the heat absorbing quality of water is far above that of air or'other gaseous mediums, the eifect of the sprays is to quickly bring the rotor down to an even temperature.

The circulation of the liquid also cools the casing and maintains it at a substantially uniform temperature throughout. Thus distortion of the casing is avoided and the blade rows remain concentric to the axis of the turbine.

Referring now to the drawing for a better understanding of my invention I show a turbine 10 having a casing 11 and'a rotor 12. Motive fluid is admitted to the turbine through a conduit 13 and, after expansion in the turbine, passes to a condenser 14. Condensate is removed fronr the condenser 1 1 by a pump 16, dischargingthrough a conduit 17 to other apparatus,not shown. Leading from the conduit 17 is a branch conduit 18 and leadingfrom said conduit 18 are a plurality of branch conduits 1919 terminating in suitable openings in the top of the turbine casing. In the conduit 18 is located a valve 21 and in each of the branch conduits 19 is located a valve, as at 22, said valves operating to regulate the flow of condensate to the turbine. In the end of each of the conduits 19 is preferably arranged a suitable form of nozzle for establishing a spray of liquid as it enters the turbine casing.

Theoperation of my improved apparatus is as follows: hen the turbine 10 has been in operation and is shut down with the rotor 12 heated to approximately the ten'iperature of the motive fluid, the natural tendency is for the heat of therotor to be carried convection to the upper part thereof so that the upper part becomes hotter than the lower part, as heretofore pointed out. By opening the valves 21 and and maintaining the pump 16 in operation, condensate is caused to spray downwardly around the rotor quickly cooling it down to an even temperature. After passing over the rotor the condensate employed in cooling it returns by gravity to the condenser 15;.

The employment of condensate as a cooling medium is preferable to that of raw water because of the fact that the greater portion of free oxygen has been removed therefrom and it is less liable to oxidize and damage the blading or other parts of the interior of the turbine. It should be furthermore pointed out that this method of cooling a turbine rotor is particularly applicable to turbines wherein the rotor and the blading have been specially treated to pre' vent oxidation. i

From the foregoing it will be apparent that I have devisedan improved means for cooling the rotor of an idle turbine wherein an even. distribution of heat tln'oughout its mass may be quickly obtained.

.Vhile I have shown my invention in but one form, it will be obvious to those skilled in the art that itis not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, andI desire,therefore, that only such limitations shall vbe placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

lVhat I claim is 1. The combination with a turbine standing idle, of means for maintaining a circulation of liquid through said turbine.

2. The combination with a turbine, of means arranged in the upper part thereof for spraying a cooling liquid downwardly into the turbine when standing idle.

3. The combination with a turbine standingidle, of a condenser for the turbine, means for removing condensate from the condenser and means forutilizing the condensate in a cooling spray forthe interior of the turbine.

4; The combination with a turbine having a casing and a rotor, ofa condenser for the turbine, a pump forremoving condensate from the condenser, and conduit means leading from the pump to the interior of the turbine in the upper part of the casing for cooling the rotor when standing idle.

6, The combination-with a turbine standing idle having a casing and rotor, of a condenser for the turbine, a pump for re moving condensate from the condenser, conduit means for conductin condensate. away from the pump, va plurality of branchvconduits communicating with the conduit means and theinterior of the turbine casing and arranged to spray condensate along the rotor for cooling the same.

7. The combination with a turbine standing idle having a casing and a rotor, of a condenser for the turbine, a pump for removing condensate from: the condenser, conduit means for conducting condensate away from the pump, a plurality of branch coir duits communicating with the conduit means and the interior of the turbine casing in the ,upper part'thereof and arranged to spray condensate along, the rotor for cooling the same and valve-'ineansfor.controlling the How of condensate through said branch conduits.

8. The method of uniformlyscooling a turbine standing idle which consists of passing a flow ofliquid therethrough'.

9. The method of uniformly coo-ling a tur him standing, idle which consists of passing a "flow of liquid therethrough and distributing said liquid tothe parts of the turbine to effect a substantially even distribution of heat throughithe turbine.

In testimony whereof, I have hereunto subscribed my name this twenty-ninth day of October, 1925. I

CARL J. LAMB;

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