US 3587638 A
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United States Patent (72] Inventors D ich Llm rech 2,159,057 5/1939 Sterrett 277/28X Eri h gha p Mulheim(Ruhr), 3,131,939 5/1964 Cuny 277/15 Gummy Primary Examiner-M. Cary Nelson  Appl. No. 755,238 A E R B R h Aug. 26, SSISIG"! xammer- OI man  Patented June 28 Allamey-Spencer and Kaye  Assignee Licentia Patent-Verwaltungs-G.m.b.I-l. I
Frankfurt am Main, Germany  Priority Aug. 24, 1967 66 4 ABSTRACT: A coolant coupling head for the intake and 1 discharge of a coolant in liquid-cooled electromachine rotors in which a protective gas chamber is provided between a coo- (541 COOLANT COUPLING HEAD lant discharge point and a seal against the external at- 3 main, I Drawing fig mosphere. A gap seal 15 provided between such protective gas chamber and a coolant collection chamber at the coolant US. Cl. di ha e oint roviding a coolant storage contalner to 277/11 277/12- 277/28 which the coupling head is connected, at a geodetic height [5 ll.-
above the oupling head and the coolant collection chamber 0| u thereof a constant amount of leakage between the coolant 277/15 28 collection chamber and the protective gas chamber is maintained via the a seal. Moreover, the rotective as chamber  References and gas rooms of the storage containerznd of a co olant return UNITED STATES PATENTS system communicate one with another and are therefore kept 1,258,218 3/1918 Hicks 277/15 under the same gas pressure.
COQLANT COUPLING HEAD BACKGROUND OF THE INVENTION The present invention relates to a coolant coupling head for the intake and discharged a coolant in liquid-cooled rotors of electrical machines, particularly turbogenerators.
Such a coupling head includes one or a plurality of protective gas chambers which are provided within the coolant coupling head between the discharge point of the coolant and a seal against the external atmosphere. Such protective gas chambers are separated from the discharge point of the coolant by a gap or sliding seal. At least one protective gas chamber serves as a leakage collection chamber for a quantity of coolant passing through the gap or sliding seal so that it can be reintroduced into the coolant circulation system of the machine. In a coolant coupling head of this type, a certain amount of coolant leakage appears between the discharge point of the coolant and the adjacent protective gas chamber, the amount of this coolant leakage depending, on the one hand, on the size of the gap or sliding seal and, on the other hand, on the pressure difference between the discharge point collection chamber and the above-mentioned adjacent protective gas chamber.
To control the quantity of the coolant leaking through the gap, a complicated regulating device has heretofore been provided which controls the gas pressure in the protective gas chamber in such a manner that this pressure is always kept somewhat lower than the pressure of the liquid at the discharge point. By thus controlling the pressures so that a small difference in pressure between the gas and liquid always exists, only a small amount of coolant leaks through the above-mentioned gap seal. Such a regulating device is, however, very expensive, susceptible to malfunction, and not able to maintain this small difference in pressure, when the gas pressure in the protective gas chamber decreases greatly.
SUMMARY OF THE INVENTION It is the object of the present invention to provide means for insuring that the amount of coolant leaking through the gap seal is kept as constant as possible and independent of the pressure of the protective gas.
The present invention provides a geodetic height between a coolant storage container provided above the coupling head (said coupling head being connected to the storage container by means of conduits), and the discharge point collection chamber of the coupling head adjacent to the gap of sliding seal such that a desired constant amount of coolant passes through the gap or sliding seal into an adjacent protective gas chamber (leakage collection chamber). The protective gas chambers and gas rooms of the storage container and ofa coolant return system communicate one with another and are all under the same gas pressure. By this arrangement, a precisely defined pressure differential is produced at the gap or sliding seal. 1
This arrangement makes possible the elimination of the complicated regulating device for controlling the protective gas pressure in the protective gas chamber of the coupling head in dependence on the pressure of the liquid in the discharge point collection chamber. The amount of coolant now leaking through the gap seal is held at an approximately constant rate since, when the gap size is predetermined, it depends substantially only on the difference in geodetic height between the coolant storage container and the collection chamber. This applies for any operational state. It is further independent of the rotational speed of the rotor. The amount of pressure of the protective gas in the protective gas chamber adjacent to the gap seal has no influence on the amount of coolant passing therethrough since the protective gas chamber as well as the entire coolant system are under the same protective gas pressure. This is very advantageous and important, for example, when special operational conditions occur, as, for example, when the shaft packing which seals the protective gas chambers from the outside comes loose so that the protective gas pressure falls to zero.
.Since, according to -the construction proposed by the present invention, there is always a constant amount of coolant leakage, it is very simple from a control point of view to recycle the amount of coolant which collects through the drain line in the leakage collection vessel into the coolant circulation stream. This is preferably done by means of a device disposed in the path of the leakage liquid drain pipe. and including a chamber, a return pump and a float-controlled regu-' lating valve. Since the amount of leakage fluid is constant, the construction of the return pump and regulation of the liquid level are very much simplified.
BRIEF DESCRIPTION OF THE DRAWING The sole drawing in the case is a schematic view of one embodiment of the coolant coupling head for use in a watercooled turbogenerator (not shown) according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT The coolant coupling head is provided with a stub shaft 2, which is flanged to the rotor shaft 1 of the turbogenerator, and a housing 5 which surrounds the stub shaft 2. The housing 5 is directly connected to the bearing member 16 of the 'turbogenerator. Above the coolant coupling head, at a geodetic height of approximately 2 meters, there is a cooling water storage vessel 28 from which coolant, in this case cooling water, is fed. The coolant is fed via a line 29 and a pump 30, into an inlet bore 3 within the stub shaft 2. From there, the coolant flows into the distribution system (not shown) of the rotor shaft 1 for purposes of cooling the same and, on its return path, the coolant leaves the stub shaft 2 via an annular return channel 4 concentrically disposed in the stub shaft 2 with reference to the inlet bore 3. The annular return channel 4 opens into a collection chamber 8 from where the cooling water is returned, via a drain line 6 and a drain pipe 31, into the storage container 28. Between the housing 5 and the stub shaft 2 there are provided two protective gas chambers 10 and 14 which are separated from each other by a separating wall 12 and an annular comb seal 11.
The chamber 10 is sealed against the collection chamber 8 by a noncontact air gap seal 9. The chamber 14 is sealed against the external atmosphere by an oil seal 15 at the rotating shaft collar 26. The tightening oil dropping from the oil seal 15 during operation is collected in the lower portion of the protective gas chamber'l4 and is removed through a line 14 having a large diameter and is reintroduced into the lubrication oil circulation. The cooling'water or coolant leaking through the gap seal 9 during operation of the generator is collected in the lower portion of the protective gas chamber 10 and is fed into a coolant return system 32 through a line or conduit 27 which has a very large diameter. The coolant return system 32 returns the coolant to the storage container 28.
A storage container 33 for N -gas furnishes the gas at a pressure of 1.5 atmospheric pressure-gauge via a line 34 to the gas room of cooling water storage vessel 28. From there the protective gas is distributed, via a line 35 to theprotective gas chambers 10 and 14, then to the drain lines 24, 27 connected to the protective gas chambers 14 and 10 and then to the return system 32.
The coolant return system 32 consists substantially of a collection vessel 36, a return pump 37 and a float-controlled regulating valve 38 (three-way valve). During operation of the generator a substantially constant amount of coolant leaks through gap seal 9 into protective gas chamber 14 from where it flows off into the collection vessel 36. The level of the coolant, in this case water, in the return system is automatically kept at approximately the level 39 by the regulating valve 38. If it rises thereahove, more cooling water than before is returned via a line or tube 4 0 into the storage container 28. If
it decreases therebeneath, more cooling water than before is pumped through tubes4l, 42 (see arrows). The pump 37 thus operates continuously. The tube 43 is an equalizing means and element 44 is an indicator column for the water level. A pressure equalization tube 45 connects the collection vessel 36 with the gas room of the regulating valve 38. From the protective gas chamber protective gas passes through the annular comb seal 11 into the protective gas chamber 14, and from there it is let off via a line 17 and a valve 19. By this means tightening oil vapors are prevented from coming to the cooling water leaked through the gap seal 9 into the protective gas chamber 10..
It will be understood that the above description of the present invention, is susceptible to various modifications, changes and adaptations.
l. A coolant coupling head device for the intake and discharge of a coolant in liquid-cooled rotors of elecvtromachines, wherein a protective gas chamber is provided within a coolant coupling head between, a coolant collection chamber at the discharge point of the coolant and a seal against the external'atmosphere and a gap seal is provided between such coolant collection chamber and such protective gas chamber, such protective gas chamber serving as a coolant leakage collection chamber for the amount of coolant leaking through the gap seal from the coolant collection chamber for the purpose of recirculating the leaked coolant through the machine, the improvement wherein a coolant storage container is provided above the coupling head, conduit means are provided for connecting said coupling head to the storage container, the coolant storage container is situated a geodetic height above the coolant collection chamber, and pressure equalizing means are provided for maintaining the same gas pressure in a gas room above coolant in the coolant storage container and in the protective gas chamber, whereby the geodetic height difference causes a desired constant amount of coolant to leak through the gap seal from the coolant collection chamber to the protective gas chamber.
2. Coolant coupling head device as defined in claim 1 wherein means for recirculating leaked coolant is provided in the path of a drain line leading from the protective gas chamber, said means for recirculating including a collection vessel connected to said drain line, a return pump, and a floatcontrolled' regulating valve means for keeping the coolant level in the collection vessel constant.
3. Coolant coupling head device as defined in claim 2, wherein said means for recirculating further includes means for equalizing gas pressureabove the float of said valve means with gas pressure above coolant in said collection vessel.