JPH07279615A - Oil discharge conduit of thermal turbomachinery - Google Patents

Abstract

PURPOSE: To shorten an oil discharge passage by guiding an oil discharge pipe of a turbo machine from a bearing casing to the outside through an exhaust diffuser, directly connecting an oil discharge conduit to a lower part of the bearing casing oil tightly and freely to operate, and leading out the oil discharge conduit through a hollow and vertical flow rib. CONSTITUTION: A rotor 1 and an impeller carrier 2 suspended inside a turbine casing 3 are disposed on an exhaust side final stage of an axial flow gas turbine. An exhaust casing 4 has annular inside part 5 and an outside part 6, and restricts an exhaust diffuser 7. Oil flows out from a bearing 9 through an oil groove, achieves an oil discharge conduit 12, and is guided to an oil tank of the outside. The oil discharge conduit 12 is connected to a spring stay 15, and formed as a spring support of a bearing casing 10. The oil discharge passage is not guided through the exhaust diffuser 7 in an axial direction, and is formed as a short oil discharge passage. The exhaust diffuser structure is lightened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil discharge conduit of a thermal turbomachine, particularly an axial flow gas turbine, which is provided with an exhaust casing following its outlet rotary vanes, the limiting wall of which is mainly on the hub side. An annular inner portion and an annular outer portion, both of which form an exhaust diffuser and are connected to each other via a plurality of circumferentially evenly distributed flow ribs. A bearing part on the outlet side of the rotor is provided in the hollow chamber inside the inner part, and the bearing casing can be positioned at a predetermined position by an adjusting member arranged in the inner part of the exhaust casing, and at least 1 Supported on the foundation via two spring stays, and the oil discharge conduit is guided from the bearing casing to the outside through the exhaust diffuser. On the.

[0002]

It is known that thermal turbomachines, in particular axial-flow gas turbines, consist mainly of rotors with vanes and vane supports suspended with guide vanes in a turbine casing. An exhaust casing is connected to the turbine casing. In modern turbomachines, the exhaust casing is not supported on the foundation, but rather is fixed to the turbine casing and consists mainly of an annular inner part and an annular outer part on the hub side, which parts are It forms the exhaust diffuser. The inner part and the outer part are connected to each other by welded radial flow ribs. These flow ribs are preferably hollow and evenly arranged in the circumferential direction. Inside the hollow part of the inner part, that is to say inside the exhaust diffuser structure, a bearing part on the outlet side of the turbine rotor is provided.

Conventionally, an oil discharge conduit is arranged in parallel with an oil pressure conduit for guiding the oil to the bearing, and the oil is led out of the bearing through the oil conduit. This oil drainage conduit is guided first from the bearing parallel to the machine axis, ie axially through the exhaust diffuser and downwards, and then to the outside via one of the large hollow ribs. The disadvantages of this known technique are that, for fluid engineering reasons, and because a relatively long exhaust diffuser is used, which advantageously extends in the axial direction, in order to positively influence the efficiency in a stationary gas turbine installation. The problem is that the oil pipe is relatively long and the oil discharge conduit is inclined.

In turbomachines of the type mentioned at the outset, the bearing part on the exhaust side, which is located inside the inner part of the exhaust diffuser, will be in the hottest environment during operation of the machine. The location of the bearings and the normally vertical load bearing points reside within the exhaust diffuser structure. Due to the low long-term fracture strength of the materials used, the entire support structure is likely to deform over time. Therefore, EP-049196
According to the 6 patent specification, it is proposed to release the bearing support on the outlet side from the effects of thermal stress and thermal expansion of the casing and the diffuser. In that case, the bearing casing is positionable by means of an adjusting member arranged in the inner part of the exhaust casing and is supported on the foundation via at least one spring stay. The connection between the bearing casing and the spring stay is made by a beam. As a result, the load of the bearing is no longer received by the exhaust diffuser structure, but is transmitted to the spring stay arranged on the foundation via the beam, and as a result, the exhaust diffuser structure can be formed in a lightweight structure, which is expensive. Heat resistant materials are saved.

[0005]

The object of the present invention is, in the turbomachinery described at the outset, not only to enable problem-free oil discharge, but also to make the oil discharge conduit as short as possible, and At the same time, the oil drain conduit is arranged so that the required number of components is as low as possible.

[0006]

According to the present invention, which has solved the above-mentioned problems, as described in claim 1, an oil discharge conduit of a thermal turbomachine, in particular, an axial-flow gas turbine, the outlet rotation of which is provided. The vane is followed by an exhaust casing, the limiting wall of which consists mainly of a hub-side annular inner part and an annular outer part, both parts of which form an exhaust diffuser, and They are connected to each other via a plurality of flow ribs that are evenly distributed in the circumferential direction, a bearing portion on the outlet side of the rotor is provided in the hollow chamber inside the inner portion, and the bearing casing is inside the exhaust casing. A positionable positioning member is positioned and is supported on the foundation via at least one spring stay, and an oil drain conduit is drained from the bearing casing. In the type that is guided to the outside through the diffuser, the oil discharge conduit is directly connected to the lower part of the bearing casing in an oil-tight and movable manner, and the exhaust gas is discharged through vertical hollow flow ribs. It is led out from the exhaust casing through the diffuser and is connected to the spring stay.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. The drawings show only those parts which are important for understanding the invention. Among the devices are compressors, combustion chambers,
The entire exhaust pipe and flue are not shown. The direction of oil flow is indicated by the arrow.

FIG. 1 shows the exhaust side and four final stages of a thermal turbomachine, in this case an axial flow gas turbine. This last stage mainly comprises a rotor 1 and a vane support 2 which is provided with guide vanes and which is suspended in a turbine casing 3. An exhaust casing 4 is flange-connected to the turbine casing 3. The exhaust casing 4 mainly comprises an annular inner part 5 on the hub side and an annular outer part 6 limiting the exhaust diffuser 7. The inner part 5 and the outer part 6 are connected to each other by a plurality of welded radial flow ribs 8, which are preferably embodied as hollow ribs and are evenly distributed in the circumferential direction. It is arranged.

The bearing part on the outflow side of the rotor 1 is arranged in the inner part 5. The rotor 1 is supported in a bearing 9, and the bearing casing 10 is positioned by an adjusting member 11 (see FIG. 3) which is a component of the inner part 5. The exhaust casing 4 flanged to the turbine casing 3 should be regarded as a rigid extension of the turbine casing 3, so that for adjusting the bearing this adjusting member 1
1 is sufficient, and all other aids that guarantee the maintenance of the bearing line are unnecessary.

FIG. 2 shows an oil drain conduit 12 located below the bearing casing 10. The oil discharge conduit 12 is fixed at its upper end to a lower part of the bearing casing 10 by a general member, for example, a ball joint 13, and is sealed via a seal ring 14.
The oil discharge conduit 12 is vertically guided through the hollow flow rib 8 in the lower part of the exhaust diffuser 7, and reaches the outside through this short path.

The oil flows out of the bearing 9 through the oil groove 16 and reaches the oil discharge conduit 12, and is guided to the external oil tank through the oil discharge conduit. If this oil tank is located low enough, no siphoning effect will occur in the oil drain conduit.

The oil drain conduit 12 is sized for buckling safety. The oil drain conduit is connected to a conventional spring stay 15 located on the foundation, which serves as a spring strut for the bearing casing 10. As a result, EP-0491966
The bearing load is no longer carried by the exhaust diffuser structure, but rather eliminated from the hot exhaust diffuser area, as described in the U.S. Pat. In other words, according to the solution of the invention,
On the one hand, the same advantages are obtained as in the EP-0491966 patent specification, while on the other hand another positive next aspect is obtained. The oil drain is no longer guided downwards through the long axial exhaust diffuser, which is considerably shorter than in the prior art. No tilting of the oil drain conduit causes any problems. Furthermore, according to the EP-0491966 patent, the oil drainage conduit itself is used instead of the beam required for the coupling of the bearing casing 10 and the spring stay 15, so that the number of components is low.

[0013]

As explained above, the advantages of the invention are in particular that a shorter oil drainage path is realized than in the prior art, the problem of tilting the oil drainage conduit is no longer present, and furthermore the oil drainage is This oil drainage conduit also serves as a spring stay for the bearing casing, provided that the conduit is dimensioned to be safe against buckling, thus reducing the number of components required. is there.

[Brief description of drawings]

The drawing shows an embodiment of the invention based on a single-shaft axial-flow gas turbine with an axial exhaust diffuser.

1 is a partial longitudinal section view of a gas turbine with an oil discharge conduit arranged according to the invention;

FIG. 2 is an enlarged view of a bearing portion shown in FIG.

3 is a cross-sectional view of the exhaust diffuser taken along line 3-3 of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 rotor, 2 blade support body, 3 turbine casing, 4 exhaust casing, 5 inner part, 6 external part, 7 exhaust diffuser, 8 flow rib,
9 bearings, 10 bearing casings, 11 adjusting members, 12 oil discharge conduits, 13 ball joints, 14
Seal ring, 15 Spring stay, 16
Oil groove

Claims (1)

[Claims] 1. A thermal turbomachine oil discharge conduit, the outlet casing of which is followed by an exhaust casing (4).
Is provided, the limiting wall of which consists mainly of an annular inner portion (5) and an annular outer portion (6) on the hub side, both of which forming an exhaust diffuser (7). And are connected to each other through a plurality of flow ribs (8) uniformly distributed in the circumferential direction, and a bearing portion on the outlet side of the rotor (1) is provided in the hollow chamber inside the inner portion (5). And bearing casing (10)
Is positionable by an adjusting member (11) arranged in the inner part (5) of the exhaust casing (4) and is supported on the foundation via at least one spring stay (15), and the oil In the type in which the discharge conduit (12) is guided from the bearing casing (10) to the outside through the exhaust diffuser (7), the oil discharge conduit (12) is directly oil-tight in the lower part of the bearing casing (10). And is movably connected to the exhaust casing (4) through an exhaust diffuser (7) through a vertical flow rib (8) formed in the hollow and connected to a spring stay (15). An oil drainage conduit for a thermal turbomachine characterized by: