CN206830245U - Extraction condensing type changes the exhaust casing cooling system of back pressure turbine - Google Patents

Abstract

The utility model relates to a rear cylinder cooling system of a steam turbine converted from a condensing type to a back pressure type. The above-mentioned thermal insulation packing layer is located in the hollow in the middle of the rear cylinder, the rear steam seal of the steam turbine and the oil shield of the rear bearing of the steam turbine; the above-mentioned heat insulation board is attached to the outer wall of the barring box; That is to say, the above-mentioned blind plate is installed at the exhaust port from the rear cylinder to the condenser. There is an air inlet on each side of the blind plate. The air outlets are connected; the above two ventilation holes are respectively located at the observation hole and the explosion-proof door of the rear cylinder. The utility model supplies air to the rear cylinder, has good cooling effect, solves the problem of excessive temperature of the rear cylinder of the steam turbine, eliminates potential safety hazards, and ensures reliable operation of the steam turbine.

Description

Rear Cylinder Cooling System of Extraction Condenser Converted to Back Pressure Turbine

technical field

The utility model relates to a rear cylinder of a steam turbine, in particular to a cooling device for the rear cylinder of the steam turbine, in particular to a cooling system for the rear cylinder of a steam turbine from a pumping condensing type to a back pressure type.

Background technique

The original 1# steam turbine of the inventor's unit was a 12MW extraction condensing steam turbine unit, which was transformed into a 6MW back pressure unit according to the needs of production and operation. After the transformation, the unit operates normally, but the temperature of the rear cylinder is too high. The longer the unit runs, the higher the temperature of the rear cylinder reaches 108°C. The temperature of the rear cylinder is too high, causing the damage of the 2# bearing bush temperature being too high and the expansion of the cylinder exceeding the standard. Yushi carried out a transformation for the purpose of cooling. During the transformation process, in order to reduce the excessive temperature of the rear cylinder, the explosion-proof door and observation hole were removed, and two fans were installed. The ventilation method was exhaust to extract the heat in the cylinder. After the steam turbine is under load and running for a long time, after the two fans are turned on, the temperature of the rear cylinder of the steam turbine will continue to rise to 120°C, posing safety hazards, and this cooling transformation method is not feasible.

The inventor has retrieved the following relevant patent documents: CN201778845U discloses a rear cylinder for a steam turbine, including a rear cylinder upper cover, a rear cylinder lower cover and a rear bearing seat cover, and the rear cylinder upper cover and the rear bearing seat cover are respectively connected with the rear cylinder The lower cover can be detachably connected, which reduces the labor intensity of workers and shortens the production cycle. The upper cover of the rear cylinder, the rear bearing seat cover and the lower cover of the rear cylinder respectively adopt welding structure, which has the characteristics of simple welding, light weight and material saving. CN204175715U discloses a cylinder cooling device, comprising a vortex tube refrigerator, a radiator, a tee joint and a hot gas pipe; the vortex tube refrigerator is provided with a compressed air inlet, a cold air outlet and a hot air outlet, The cold air outlet of the vortex tube refrigerator communicates with the first input end of the three-way joint; the hot air outlet of the vortex tube refrigerator communicates with the second input end of the three-way joint through a hot air pipe, and a radiator is connected in series on the hot air pipe ; The output end of the three-way joint communicates with the intake end of the cylinder.

The above technologies have not given specific guidance on how to make the rear cylinder cooling system of the extraction condensing type to back pressure steam turbine can significantly reduce the temperature of the rear cylinder, so as to ensure the reliable operation of the steam turbine.

Contents of the invention

The purpose of the utility model is to provide a cooling system for the rear cylinder of the steam turbine from the condensing type to the back pressure type, so as to solve the problem of the high temperature of the rear cylinder of the steam turbine, thereby eliminating potential safety hazards and ensuring the reliable operation of the steam turbine.

For solving the problems of the technologies described above, the technical scheme that the utility model adopts is as follows:

A cooling system for the rear cylinder of an extraction condensing type to back pressure steam turbine (or a cooling device for the rear cylinder of an extraction condensing type to back pressure steam turbine), which has a rear cylinder and a barring box, and its technical solution lies in the above The rear cylinder cooling system of the extraction condensing type to back pressure steam turbine also has an insulation packing layer (insulation material layer), a heat insulation plate, a blind plate, two marine fans, and two ventilation holes. The above insulation packing layer is located in the rear cylinder, The hollow in the middle of the oil shield between the rear steam seal of the steam turbine and the rear bearing of the steam turbine (that is, 2# bearing bush); the above-mentioned heat shield is attached to the outer wall of the crank box; the exhaust port at the bottom of the rear cylinder is the rear The above-mentioned blind plate is installed at the exhaust port from the cylinder to the condenser. There is an air inlet on both sides of the blind plate. The air supply port of each marine fan is connected to an air inlet on the corresponding blind plate through a pipeline. The above two ventilation holes are respectively set at the observation hole and the explosion-proof door of the rear cylinder (that is, the observation hole and the explosion-proof door of the rear cylinder are opened). The above-mentioned marine fan performs forced ventilation and heat exchange (air supply) to the rear cylinder to reduce the temperature of the rear cylinder. The utility model supplies air to the rear cylinder. During operation, only one marine fan can be used to reduce the temperature of the rear cylinder, and the other one is used as a backup.

In the above technical solution, the heat insulation board is preferably arranged around the outer wall of the crank box body, and the heat insulation plate extends along the length direction of the crank box body (that is, along the direction of the centerline of the handwheel on the crank box body) Stretching), the length of the heat shield is preferably equivalent (equal) to the length of the cranking box. The above-mentioned thermal insulation filler layer is preferably aluminum silicate needle-punched felt. The above-mentioned heat shield is preferably made of two stainless steel plates and a high temperature resistant asbestos plate sandwiched between the two stainless steel plates.

The rear cylinder cooling system of the condensing type to back pressure steam turbine described in the utility model also has a thermal insulation packing layer, a heat insulation plate, a blind plate, two marine fans, and two ventilation holes. The above thermal insulation packing layer is located in the rear cylinder 1. The hollow in the middle of the oil shield between the rear steam seal of the steam turbine and the rear bearing of the steam turbine (that is, the 2# bearing bush); the above-mentioned heat shield is attached to the outer wall of the crank box; the exhaust port at the bottom of the rear cylinder is The above-mentioned blind plate is installed at the exhaust port from the rear cylinder to the condenser. There is an air inlet on each side of the blind plate. The air supply port of each marine fan passes through the pipeline and an air inlet on the corresponding blind plate. The above two ventilation holes are respectively set at the observation hole of the rear cylinder and the position of the explosion-proof door. In this way, the marine fan performs forced ventilation and heat exchange (air supply) to the rear cylinder to reduce the temperature of the rear cylinder. The utility model supplies air to the rear cylinder. During operation, only one marine fan can be used to reduce the temperature of the rear cylinder, and the other one is used as a backup. After testing, it is feasible to adopt the cooling system of the utility model, and the manufacturing cost is low. After the unit runs for a long time (4~6 hours), the temperature of the rear cylinder is 85°C, the temperature of the rear cylinder is reduced by more than 20%, and the cooling effect is good. , thereby eliminating potential safety hazards, ensuring reliable operation of the steam turbine, reducing the failure rate of the steam turbine by more than 25%, and greatly extending the service life of the steam turbine.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a (partial) view from direction A in Fig. 1 .

detailed description

As shown in Fig. 1 and Fig. 2, the rear cylinder cooling system of the condensing type to back pressure steam turbine of the present invention has a rear cylinder 1, a crank box 4, a thermal insulation packing layer 10, a heat insulating plate 3, and a blind plate 6. Two marine fans (two centrifugal fans) 8 and 8', two ventilation holes 2 and 2'. The thermal insulation packing layer 10 is located in the middle depression of the rear cylinder, the rear steam seal 9 of the steam turbine, and the oil shield of the rear bearing (ie, 2# bearing bush) 5 of the steam turbine. The above-mentioned heat insulation board 3 is attached and installed on the outer wall of the crank box body 4 . The above-mentioned blind plate 6 is installed at the exhaust port at the bottom end of the rear cylinder 1, that is, at the exhaust port from the rear cylinder to the condenser, and each side of the blind plate 6 has an air inlet 7, 7', and each marine fan The air supply ports of 8 and 8' communicate with one of the air inlets 7 and 7' on the corresponding blind plate through pipelines. Above-mentioned two ventilation holes 2, 2' are respectively arranged at the observation hole and the explosion-proof door position of the rear cylinder (the observation hole and the explosion-proof door of the rear cylinder are about to be opened). The above-mentioned marine fan performs forced ventilation and heat exchange (air supply) to the rear cylinder to reduce the temperature of the rear cylinder. The utility model supplies air to the rear cylinder. During operation, only one marine fan can be used to reduce the temperature of the rear cylinder, and the other one is used as a backup.

As shown in Figure 1 and Figure 2, the above-mentioned heat insulation board 3 is arranged around the outer wall of the crank box body 4, and the heat insulation board 3 extends along the length direction of the crank box body 4 (that is, along the handwheel on the crank box body The direction of the central line extends), and the length of the heat shield 3 is equivalent (equal) to the length of the crank box 4. The thermal insulation filler layer 10 is aluminum silicate needle felt. The heat shield 3 is made of two stainless steel plates and a high temperature resistant asbestos plate sandwiched between the two stainless steel plates.

After testing, it is feasible to adopt the cooling system of the utility model (i.e. the above embodiment), and the manufacturing cost is low. After the unit runs for a long time (4~6 hours), the temperature of the rear cylinder is 85°C, and the temperature of the rear cylinder is reduced by 20°C. % or more, the cooling effect is good, thereby eliminating potential safety hazards, ensuring the reliable operation of the steam turbine, reducing the failure rate of the steam turbine by more than 25%, and greatly extending the service life of the steam turbine.

Claims (4)

1. A rear cylinder cooling system of an extraction condensing type to a back pressure type steam turbine, having a rear cylinder (1) and a barring box (4), characterized in that the rear cylinder of the extraction condensing type to a back pressure type steam turbine The cooling system also has a thermal insulation packing layer (10), a heat insulation plate (3), a blind plate (6), two centrifugal fans (8, 8′), two ventilation holes (2, 2′), and the above thermal insulation packing The layer (10) is located in the hollow in the middle of the rear cylinder, the rear steam seal (9) of the steam turbine and the oil shield of the rear bearing (5) of the steam turbine; the above-mentioned heat insulation board is attached to the outer wall of the barring box (4) (3); The above-mentioned blind plate (6) is installed at the exhaust port at the bottom of the rear cylinder (1), that is, at the exhaust port from the rear cylinder to the condenser, and each of the two sides of the blind plate (6) has an inlet The air outlet (7, 7'), the air outlet of each centrifugal fan (8, 8') is connected with an air inlet (7, 7') on the corresponding blind plate through the pipeline; the above two ventilation holes (2, 2') are located at the observation hole and explosion-proof door of the rear cylinder respectively. 2. The cooling system for the rear cylinder of the condensing type to back pressure steam turbine according to claim 1, characterized in that the above-mentioned heat insulation board (3) is arranged around the outer wall of the crank box (4), and the heat insulation board ( 3) Extend along the length direction of the cranking box (4), that is, the heat shield (3) stretches along the direction of the centerline of the handwheel on the cranking box, and the length of the heat shield (3) is the same as that of the cranking box (4) are equal in length. 3. The cooling system for the rear cylinder of a condensing-type to back-pressure steam turbine according to claim 1, characterized in that the above-mentioned thermal insulation packing layer (10) is aluminum silicate needle-punched felt. 4. The cooling system for the rear cylinder of the condensing-type to back-pressure steam turbine according to claim 1, characterized in that the above-mentioned heat shield (3) is made of two stainless steel plates and a high temperature resistant steel plate sandwiched between the two stainless steel plates. of asbestos panels.