JPS63167001A - Reaction turbine - Google Patents

Abstract

PURPOSE:To balance the thrust of a turbine axle, to heat steam in bleed air chamber and to improve internal efficiency of a turbine by introducing leakage steam from a labyrinth packing into a bleed air stage chamber of a reaction turbine through a balancing pipe. CONSTITUTION:A moving blade array 2 and a stationary blade array 3 as reaction blade are provided on a turbine axle 1, and a balancing piston 6 inte gral with the turbine axle 1 is disposed upstream from the moving blade array 2. A bleed air chamber 5 is formed in a turbine casing 11, and a bleed air pipe 22 is connected to the bleed air chamber 5. In this arrangement, there is provided a balancing pipe 24 for introducing leakage steam from a leakage steam chamber 19 into a bleed air stage 5a of the turbine casing 11. Pressure of bleed air steam from the bleed air chamber 5 is applied to one end surface 6a of the balancing piston 6, and steam pressure from a steam inlet chamber 7 is applied to the other end surface 6b thereof. Further steam of the bleed air stage 5a is heated by high-temperature steam leakage from labylinth packing 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reaction turbine that is operated by disposing a balancing piston on the turbine axle and balancing the axial thrust applied to the axle during operation. 1. [Prior Art] A reaction turbine having reaction blades causes a high-speed steam flow ejected from a stator blade attached to a turbine casing to flow into a rotor blade attached to a turbine axle consisting of reaction blades, thereby generating a high-speed steam flow. The turbine axle is rotated by applying an impulse force due to a change in the direction of the rotor blades and a reaction force resulting from the expansion of steam within the rotor blades, that is, the pressure drop resulting in an increase in the flow velocity of the steam, to rotate the turbine axle.
They are made to do mechanical work. In this case, since steam is expanded in the rotor blades, the steam pressure at the inlet of the rotor blade is higher than at the outlet. Therefore, the turbine axle receives a thrust in the direction in which the steam flows1.In order to balance this thrust, a balancing piston is provided on the turbine axle to generate a force in the opposite direction to the thrust to balance the turbine axle. The prior art will be explained below based on the attached drawings.

FIG. 3 is a schematic diagram of the reaction turbine. In the figure, a turbine axle 1 has a rotor blade, which is a reaction rod, and both ends of the rotor blade are supported by bearings 9 and 1o, respectively. 11 is a turbine casing, and rotor blade rows 2 and 3 of the turbine axle 1
It is provided with a row of stator blades 12 and 13 that are combined with each other to form a blade section, and also surrounds the turbine axle 1 and rotatably supports it via bearings 9 and 10.

Further, on the upstream side of the high-pressure blade row formed by combining the reaction blade row 2 of the turbine axle 1 and the stator blade row 12 of the turbine casing 11, a balance piston 6 is provided.

Downstream of a low-pressure blade row formed by combining a small space consisting of a steam inflow chamber 7 and a leakage steam chamber 19 defined by the inner peripheral surface of the turbine casing 11 surrounding it, and a first reaction blade row 3 and a stator blade row 13 Exhaust steam defined on the side by the inner peripheral surface of the turbine casing 11 and the turbine axle 9 and the turbine casing 1
A steam inflow chamber 7 and a leakage steam chamber 19 are separated by a labyrinth packing 16 disposed on the inner peripheral surface of the steam chamber 1. The steam inflow chamber 7 is.

A steam pipe 20 is connected to supply the steam sent into the turbine casing 11. The supplied steam expands in the blade row stage and flows through it while doing work, reaching the exhaust steam chamber 14, and passes through the exhaust pipe 21 to a condenser (not shown).
The water is sent to the water, becomes condensate, and is used. In the turbine casing 11, an air bleed chamber 5 is formed between a blade row portion consisting of a reaction blade row 2 and a stationary blade row 12 and a blade row portion consisting of a reaction blade row 3 and a stationary blade row 13. A bleed pipe 22 is connected to the bleed chamber 5 of the labyrinth seal 16 and communicates with a factory steam pipe (not shown), etc., and is configured to allow steam leaking from the labyrinth packing 16 to join the bleed pipe 22. Leakage steam is now used together with extracted steam for factory steam, etc.

[Problem that the invention seeks to solve]

In the reaction turbine configured as described above, steam leaking out of the labyrinth packing 16 flows into the leakage steam chamber 19 with an isenthalpic change with the steam in the steam inlet chamber 7, so that the steam temperature in the leakage steam chamber 19 is lower than that in the steam inlet chamber. Close to the steam temperature of 7. However, the steam temperature in the bleed chamber 5 is considerably lower than the steam temperature in the steam inlet chamber 7 because work is done by flowing through the blade row consisting of the rotor blades 2 and the stator blades 12, but the leak steam chamber 19 The steam passes through the balance pipe 23 to the bleed pipe 2.
2, the energy of the high-temperature leaked steam is fully utilized and discharged to the outside via the bleed pipe 22 without causing the turbine to do any work, which reduces the internal efficiency of the turbine.

In view of the above-mentioned points, it is an object of the present invention to provide a reaction turbine that can effectively utilize steam leaking from a labyrinth packing to improve the internal efficiency of the turbine.

[Means for solving problems]

In the present invention, a balance pipe is provided for extracting leaked steam from a labyrinth gasket provided between a balance piston provided on a turbine axle and a turbine casing and sending it to the extraction stage of one reaction turbine.

[Effect]

As mentioned above, the steam leaking from the labyrinth packing was led to the bleed chamber stage of the reaction turbine through the balancing pipe, so the thrust of the turbine axle was balanced by the balancing piston, and the high temperature steam leaking from the labyrinth packing was Only the amount of steam flowing into the stage and the amount of steam leaking out is 1'?
)02tJ-The explanation will be supplemented with reference to FIG. 2 below. Second
The figure shows the Moliny HS line (or steam HS line), with the vertical axis representing dynthalpy and the horizontal axis representing entropy, showing the heat drop in the turbine. In the figure, point A is the enthalpy of steam flowing into the turbine.

Point B represents the enthalpy when the incoming steam passes through the blade row and expands adiabatically due to isentropic changes up to the pressure P curve. Curves p and I curve Pa represent the isopressure line with point B and the isopressure line of extracted steam, respectively; 1 curves T, Ta and Tb are the 0 point, D
It is a temperature line passing through point and E point.

However, during actual expansion within the turbine, the entropy increases, resulting in steam having an enthalpy equal to the intersection point C between the constant pressure line P and the temperature line T. Similarly, the enthalpy of the extracted steam is the value at the intersection of the constant pressure line Pa of the extracted steam and the temperature wATa. Therefore, what is used for this Turpin work is
It is the sum of the heat drop h1 between the seasons and the heat drop h2 between the times, and the internal efficiency at this time is h1+h2. By the way, as in the present invention, when the high temperature leaked steam from the labyrinth packing is sent to the bleed stage, the steam in the bleed stage is heated and its temperature rises to the temperature line Tb, so the enthalpy of the steam in the bleed stage is equal to that of the bleed steam. It moves to the upper right on the pressure line Pa by the amount of temperature rise, and reaches the intersection E of the temperature line Tb and the constant pressure line Pa.

Therefore, the steam flowing through the blade row stage after the bleed stage expands along the constant pressure line pl of the exhaust chamber, so it performs work by reducing the pressure and temperature to point F. Therefore, the work done by the steam when configured as in the present invention is the heat drop between D and the heat drop between gaps h3.
It becomes the sum of In this case, h2<ha, so increase the heat drop by that difference.

Also, the amount of steam increases by the amount of leaked steam flow.

The amount of work that can be used increases accordingly.

[Example of idea]

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram of a reaction turbine according to an embodiment of the present invention. In FIG. 1, parts that are the same as those in the conventional example shown in FIG. 3 are given the same reference numerals, and their explanations will be omitted.

In FIG. 1, the leakage steam from the leakage steam chamber 19 is as follows.

The flow is arranged to be delivered to the bleed stage 5a of the turbine by means of a balance pipe 24, which is connected at one end to the bleed stage of the turbine casing. Therefore, the pressure of the bleed steam in the bleed chamber 5a is applied to the end surface 6b of the balancing piston 6, as in the prior art.
On the other hand, since the steam pressure in the steam inlet chamber 7 is applied to the end face 6a of the balancing piston 6, it balances the thrust from the reaction blades mentioned above, and the high-temperature steam leaking from the two cylinders heats the steam in the extraction stage. This increases the temperature of the steam in the bleed chamber and increases the amount of steam in the bleed chamber by the leaked steam, thereby increasing the amount of work that can be used by the blade rows after the bleed chamber.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the steam leaking from the balance piston shell and rinse packing is guided to the bleed stage, so that the thrust from the first reaction vane is balanced by the balance piston, and the leaking steam is used to bleed air. The steam in the chamber is heated to raise its temperature to increase the heat drop used by the turbine, and the steam flowing in the line after the extraction stage is increased by the amount of leaked steam, so the amount of work given to the turbine is increased. It is possible to improve the internal efficiency of the turbine.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a reaction turbine according to an embodiment of the present invention, and FIG. 2 is a steam-hs diagram showing the heat drop of the turbine.
- diagram, FIG. 3 is a schematic configuration diagram of a conventional reaction turbine.4゜1: Turbine axle 52t3: bucket row, 5: bleed chamber. 5a: extraction stage, 6: balance piston, 7: steam inflow chamber. 11: Turbine casing, 12, 13: Stator blade row, 1
6: Lapilin packing, 19: Leaking steam chamber, 22: Bleeding pipe, 23, 24: Balancing pipe. , π゛go'' Fig. 1 Δ Nitrobi Fig. 2

Claims (1)

[Claims] In a reaction turbine configured to bleed flowing steam to the outside through a bleed chamber provided in an intermediate stage of the casing of a steam turbine, a shaft generated by steam flowing through the casing stage from the high-pressure side to the low-pressure side. A balancing pipe is provided to take out leaked steam from a labyrinth packing part provided between a balance piston provided on the turbine axle and the turbine casing in order to balance the directional thrust and send it to the extraction stage. A reaction turbine featuring: