US1791585A

US1791585A - Hydraulic turbine

Info

Publication number: US1791585A
Application number: US39904A
Authority: US
Inventors: Clark A Terry
Original assignee: International Paper Co
Current assignee: International Paper Co
Priority date: 1925-06-27
Filing date: 1925-06-27
Publication date: 1931-02-10
Anticipated expiration: 1948-02-10

Description

Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE CLARK A. TERRY, OE GLENs PALLs, NEW YORK, AssIeNOR To INTERNATIONAL PAPER COMPANY, A CORPORATION OE NEW YORK HYDRAULIC TURBINE Application filed .Tune 27,

This invention relates to hydraulic turbines and aims to prevent vibration due to the constant malring and breaking of the vacuum in the draft tube and tail race,and tol increase the efciency of operation.

lt is well known to those familiar with the operation of hydraulic turbines, that there is a tendency of the water column to pulsate in the draft tube, which is more or less pronounced according to the varying conditions Y with respect to the changes in load, the action yof the governor, the sudden closing of the turbine gates, and other conditions encountered in theypractical operation of the mech.-

The momentum of the water column in the draft tube under the conditions mentioned, causes the column to break, and on the column being arrested by the creation of the vacuum due to the break, the column is thrown upwardly again by the atmospheric pressure, and these actions being rapidly repeated, result in violent pulsa-tions of the Water column, with the vacuum constantly making land breaking in the draft tube and tail race, and subjecting the mechanism to violent, injurious and annoying vibrations which greatly interfere with the eiciency of operation.

In accordance with the present invention this objectionable action of the turbine is prevented by the provision of means of improved form and construction which, on the tendency of the creation of avacuum in the draft tube by the break ofthe water column, will act automatically to admit air to the water column and thus check the creation of a vacuum I such as would bring about the objectionable actions above described.

In its more detailed form the invention consists of a suction relief instrumentality in the form of a valve applied in a passage leading from the outside atmosphere to the interior of the draft tube, which valve is spring pressed on its seat so as to prevent the escape of water outwardly from the draft tube under normal conditions of operation, but is capable when the force of the spring is overcome, to yield and open inwardly and thereby admit air to the draft tube, such opening movement of the valve being effect- 1925. Serial No. 39,904.

ed automatically when the suction of the water in the draft tube reaches a predetermined point.

The invention consists also in the provision of means for mullling the' action of the valve in itsv opening and closing movements, so as to silence its operation to a minimum.

In the accompanying drawings:

Fig. lis a sectional elevation of a hydraulic turbine having my invention applied thereto.

Fig. 2 is an elevation partly in section on an venlarged scale of the air admission valve mechanism. y

Fig. 3 is a cross section through the same on the line 3-3 of Fig. 2.

Referring to the drawings: v

l designates a hydraulic turbine provided as usual with the rotor 2 carried by a rotor shaft 3, to which rotor water is admitted through the intake chamber l surrounding the rotor, and from which the water flows downwardly through a draft tube 5 and finds its'escape through a tail race G.

7 designates a valve mechanism, which in accordance with my invention, is applied from the outside atmosphere and communicating with the interior of the kdraft tube. The pipe 8 has its inner end exposed within the draft tube and extends through the wall thereof and has its outer end disposed in a lateral passage at the lower end of the inspection pit 9 leading upwardly to the outside air through the masonry surrounding the Vturbine'. The valve mechanism 7 comprises a valve casing 10 connected at its inner end to the outer end` of the pipe 8 and connected at its outer end to the inner'end of a cylindrical perforated shell 12. The valve casing is provided with a valve seat 13, against which seats an inwardly opening valve lst carried by a valve stem l5 which is guided at its inner end in a spider 16 fixed in the valve casing. llhek valve stem extends outwardly within the cylindrical shell 12 and through the outer end of the same and is acted on by a spring 17 surrounding the outer exposed end of the stem and bearing against the end of the cylindrical shell and against an adjustable head 18 on the end of the stem,

to the outer end of a passage or pipe 8 leading the tendency of the spring being to hold the valve yieldingly on its seat, and thereby close the communication of the pipe 8 with the outside atmosphere.

The valve thus applied and held yieldingly to itsi'se'at bythe spring, will'p'revent the escape of Water "from the draft tube and is capable of opening inwardly when the suction of the Water within the draft tube reaches a predetermined degree and the force of the spring is overcome, suoli inward opening of the valve permitting' air to flow 'inwardly through the perforated shell and pipe 8 and into the draft tube and thus acting to relieve 1 said abnormal suction. Under the normal 'opeation ofl the turbine, with the water flowingdownwardly through the draft tube,the valve will be held closed by `its spring, thereby' iiiairtaining thatdegree of suction Vof the Water in 'the `draftV tube which is character is'ticof'tl'e iiormal action ofthe downwardly tlilvving"Yvater. Whenhowe'ver the conditions are such that the suction of the water in- Icreases to an abnormal degree with a tendlsency ofthe' watercolumn to break and the *"creation'of a vacuum, the va lve will be opened autbriiaticallyagainst'the force of the spring by the atmospheric pressure, and air will be "admitted tothe draft tube and the" tendency 130 of the column to breakl will be checked. In

this manner the valvewilly act to automatii 'allyprevent pulsations and vibrations of the water column, and while opening automati-V "ally 'to admit air according to the degree of "`r`s'ctionl obtaining within the draft'tube, it

i will under normal conditions of operation "prevent the escape of the water from the draft tube and will maintain that degree of suction inthe tube which is characteristic of the nor- Ao mal 'operation of the turbine.

' Inolrder to reduce the soundof the inrushing air on the opening/'of the valve and relieve the same-of undue noise,lmeans are provided to muil'le the mechanism, which means 1n the @p present' case is inthe form of a mass 19 of curled hair or likeniaterial which is packed in` the perforated shell in the annular space between the same and an internal perforated '-tube 20' sustained centrally within the shell j fand 5surrounding the valve stem. The mass of*`m`ziterial thus applied while permitting "the passage of the air through the perforated` shell and perforated tube and its entrance """into` the draft tube on the opening of the "55"valve', willeifectually silence the action of i' the rapidlyllowing stream of air and Vwill at x. the' same time act to filter the air. 'TheI improvedl mechanism constructed and appled'as above described is positive and re` liable in action, is adapted for application to Jany form of draft tube, and is readily" i"adjustable so as to operL te under varying ydegrees of suction lwithin the tube according to the'` varying conditions encountered in practice. By preventing the pulsations and vibrations ofthe water column, which are not only annoying and disturbing in the plant but frequently of an injurious and destructive character, the eiiiciency of the turbine is greatly increased and safety in operation assured.

It'maybe desirable to apply to the pipe 8, a vacuum gage 2l, and to apply a gate valve 22 to the pipe between the gage and valve mechanism 7, as shown in Fig. 2.

In the foregoing description and accom panying drawings I have set forth one form of embodiment of the invention by way of example, but it will be manifest to the skilled mechanic that the details of the mechanism and its mode of application lma be variously changed-without departingI rom the spirit of the invention; and it will be understood that the invention is not limited to any particular form or construction of the parts except in so far as such limitations are specified in the claims.

lIIa-ving thus described my invention, what I claim is l. In combination with a hydraulic turm90 inwardly opening valve and adjustable means' 595 to control the opening of said valve, and responsive automatically directly to a'predetern'iined degree of suction of the water therein to admit air automatically to the water column when said degree of suction isf?- vreached; whereby vibration of the Water column will be prevented.

` 2. In combination with a hydraulic turbine of the suction type having a draft tube in which the water column submergesthe turbine rotor, an air inlet'mechanism associated with the draft tube and comprising an inwardly opening valve and adjustable means to control the opening of said valve,and responsive'automatically directly to a predetermined degree ofsuction of the water therein tol admit air automatically to the water column when said degree of suction is reached, said valve when closed acting to prevent the escape of water through it.

3. In combination with a hydraulicturbine of thereaction type having a'draft tube in which the water column submerges the tur* bine rotor, an air inlet valve applied to said draft'tube and an adjustable springacting on said valve to hold it yieldingly closed, said valvel being constructed tojbe opened automatically by the suction of the waterin said tube when saidsuction reaches a predetermined degree; whereby air will be admitted automatically to the wat-er column and vibrationV of the same will be' prevented.

In combination with a hydraulic turbine of the reaction type having a draft tube turbine rotor, a normally closed inwardl opening air inlet Valve applied to said dra tube, said valve being constructed to be automatically opened and admit air to the draft tube When the suction of the Water n said tube reaches a predetermined degree, and adjustable means to control the opening of said Valve whereby the vibration of the Water column, and the escape of the Water through the valve, Will be prevented.

n testimony whereof, I have aiixed my signature hereto.

CLARK A. TERRY.