US1791849A - Seal tightening for centrifugal machines - Google Patents

Description

l Parenteel Feb.1o, 1931 UNITED STATES PATENT oFFlc-'E GEORG STAUIBER, OF BERLIN, GERMANY SEAL '.lIGrH'lENINGrl FOR CENTRIFUGAL MACHINES Application led' October 6, 1927, vSerial No.

`In rotary or centrifugal machines appreciable clearance losses are produced between the rotating wheels and the casing'. In order to reduce these losses the clearance between the wheel and casing may be reduced in a known manner-as by a flexible sliding riable liquid pressure. in the passage of the discharging liquid and ofthe counter-acting the clearance walls,

forces automatically adjusts itself to the smallest' clearance opening.

The-'object of the present invention is to reduce the losses in a more effective way than has been possible by the devices heretofore known,and the invention consists in that of which one is movable withrelation to the other in the direction of the enlargement or reduction of the clearance, is so formed that the clearance cross section is continually reduced in the direction of liow of the clearance liquid. By this construction a much higher eiiciency is obtained than with parallel clearances. Consequently, eration it will be possible to adjust the clearance much more accurately and to thus maintain the water losses far less than in the case of the known arrangement of clearances with parallel walls.

In the accompanying drawing wherein the invention is illustrated the figure is a detail section showing the invention applied to use.

Referring to the drawing in detail the numeral 1 indicates the wheel, 2 the casing and 3 the clearance between them to be sealed.

The tightening is effected by a packing ring 4 which according to the invention is of a special form and bymeans of which the continuous reduction in the clearance space -pressure is highest when with the same effectiveness in opl-- 224,495, and in Germany October 13, 1926.

is obtained. The form in the embodiment illustrated is such that when the counter surface at the runner is flat the side of the ring opposed to said surface is so taperedthat it may -only bear against the runner along a circular line so that between the ring andthe runner a contracting passage 6 is formed, this form being further characterized in that between the .side of the ring in front of the casing and the casing itself a 'pressure space 5 is provided. The spaces 5 and 6 communicate with each other and with the clearance Sto be sealed. In the pressure space 5 there exists a substantially constantpressure dependent upon the different clearance pressures at the circumference of the Iclearance space 3. ,The l'ire'ssure4 space 5 opposite the casing wall 2 is elastica'llysealed by a ring 7 other suitable material. Inl thelpassag'e 6 approximately the same .pressure 1 exists as in the space 5 provided the ring 4 fits the wall l so closely that no water flows between them. By the contraction or reduction of thepassage '.6 outwardly, which is an important factor in proper packing, the pressure acting upon the tapered wall ofthe packing ring located on the runner side is highly variable, and in such manner that the the packing ring 4 closely Hfits the runner 1 and steadily decreases the fartherl the packing ring is removed from said runner.

Since the counter pressure exerted by the liquid in the space 5 upon the ring 4 remains substantially constant, the packing ring w1ll remain in a state ofequilibriumin that position in which the pressure on the side of the clearance balances the pressure of the liquid in the space 5 and the spring forces act in the same direction where such are present.

If the packing ring 4 tends to approach side of the clearance upon the packing ring surrounded by adouble, ring'f'8 of rubber. or

lthe runner wheel l, the quantity of the dis- 4 so that the packing ring is displaced from the runner.

Thus the free movability of the ring 4 is essential for the mode of operation of the device, and this ring therefore must be fastened to the casing in such manner that it may freely adjust itself in the way above set forth. As herein shown, this adJustment is permitted by suitable springs arranged on bolts loosely holding the ring 4 in attached relation to the casing 2, one of said springs being indicated at 9.

By means of the sealing device according to the invention it is not intended to produce a condition in which no Awater whatever dis\ charges between the runner wheel and the packing ring. This condition would result with wear of the ring 4 and in corrosion of the fiange of the wheel. It is intended, on the contrary, by shaping the packingring 4 to enable the discharge and waste of a certain quantity of water between the runner and the packing ring, but only as much as will be necessary to obtain effective liquid lubrication between the wheel and the ring and to avoid mutual wear. This intentionally caused loss of water obviously involves a loss of energy which, however, is substantially lower than that which results with other types of sealing devices.

The load surfaces on both sides of the ring 4 are so dimensioned that the packing ring in the position of equilibrium closely approaches the runner wheel, thus permitting a slight water discharge, suiicient, however to leave an adequate layer of lubrication between the runner and the packing ring and to prevent mutual wear of the latter.

The characteristic of the invention is the shaping of the clearance walls in such manner that aclearance contracting or decreasin in' the direction of ow is formed.

claim:

1. In a fluid pressure turbine having a casing and rotor mounted'therein provided with a runner clearance sealing means between the runner and the casing including a ring interposed between one side of the runner and the casing, the opposing side faces of the runner and the ring being spaced apart to provide a y clearance passage therebetween and said ring having a single circular line of contact with the face of the runner at the outer side of said clearance passage, and means for yieldingly mounting said ring upon the casing whereby said ring is mova ly responsive to variable iluid pressures in the clearance passage.

2. In a'iiuid pressure turbine having a casing and rotor mounted therein provided with a runner; clearance sealing means between the runner and the casing including a ring interposed between one side of the runner and the casing, the opposing side faces of the runner and the ring'being spaced apart to provide a clearance passage therebetween and mounting sai ring upon the casf casing at the outer side of said pressure chamber.

3. A fluid pressure turbine having a casing and a rotor mounted therein provided with a runner, a sealing ring, and means, for movably mounting said ring upon the casing for movement towards and from one side of the runner, the said side face of the runner and the opposing' side face of the ring extending in convergent relation to each otherV to provide a clearance passage gradually diminishing in cross sectional area towards the discharge side of said assage, and said ring at the dischar e side oi) the passa e having a single line o circular contact with the side face of the runner, and said ring moving relative to thev runner to increase the area of the clearance discharge in corespovndence with increments of increase of uid pressure in the clearance passage.

In testimony whereof I have signed my name tothis specification.

DR. GEORG STAUBER.

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