What is the steam action of the three stage shaft of the steam turbine? What is the function of the

The most advantageous extraction pressure should both heat the feed water to a given feed water temperature and maximize the work done by the extraction steam in the turbine. When the recuperative steam extraction is used to heat the feed water, the feed water temperature increases with the increase of the steam extraction pressure, and the thermal economy also increases. When the pumping pressure reaches a certain value, the thermal economy reaches its maximum, and the feed water temperature at this time is called the theoretical optimal feed water temperature.

The third section of the shaft seal leaks steam? The outermost two sections of the shaft seal are the shaft seal air supply and the shaft seal leakage to play a sealing role, for the high-pressure cylinder part, let the air at the end leak in, through the shaft seal heater to extract away, so that the steam in the cylinder will not leak into the air; For the low-pressure cylinder part, it is also pumped by the shaft seal heater, but the purpose is not to let the outside air enter the cylinder, but to enter the steam seal of the suction section, and then all the air is pumped out.

In addition to the shaft seal air supply and extraction at the end, if there is a third, fourth, and fifth sections, these are connected to the high-add, low-add, or deaerator, the purpose is to let the high-pressure steam segment leak a part of the heater, ** heat, and at the same time avoid the steam leaking into the air (if the pressure is too great, the flow is too large, the shaft seal heater can not be pumped, the burden is too great, and it will leak out).

In addition, when the unit is hot starting, the cylinder is hot, and the rotor temperature should be lower, and the heat absorption and heat dissipation are very fast), and the reverse steam can be supplied through the shaft seal to heat the rotor, so as to avoid excessive negative expansion of the unit.

The three-stage shaft steam of different power plant steam turbines is used differently, and you had better upload your axle steam system diagram to see the ins and outs of the steam to correctly tell your use.

When the steam turbine is inlet, the pressure on the inlet side is high and the pressure on the outlet side is low, so that the pressure difference between the inlet side and the steam outlet side of the steam turbine is generated, and this pressure difference acts on the blades of the steam turbine to produce axial thrust, so that the steam turbine rotor produces shaft channeling. When the pressure difference is constant, the larger the steam flow, the greater the shaft channeling.

Steam turbine shaft channeling refers to the phenomenon that the rotor of the steam turbine generator set moves in the axial direction. The axial positioning of a steam turbine relies on thrust bearings, and axial channeling usually occurs due to increased axial thrust or damage to thrust bearings.

The axial clearance between the rotor and the stator of the steam turbine is very small, when the axial thrust of the rotor is too large, resulting in the melting of the thrust bearing Wujin, the rotor will produce the impermissible axial displacement, resulting in the friction of the dynamic and static parts, resulting in serious damage to the equipment, so the steam turbine is equipped with axial displacement protection device. Its function is: when the axial displacement reaches a certain value, an alarm signal is issued; When the axial displacement reaches a dangerous value, the protection device acts, cuts off the steam intake of the steam turbine, and stops the machine.

The axial displacement is subject to load changes; vacuum variation; steam temperature change; the effects of blade breakage or water shock during operation; In addition, the blades are seriously scaled; steam flow rate changes; The presence of water in the oil, etc., can also affect its variation.

When the axial displacement increases, the inlet and outlet oil temperature, thrust pad metal temperature, expansion difference and unit vibration of the thrust bearing should be closely monitored. If the parameters of the main and reheat steam are abnormal, they should be restored to normal; When the axial displacement increases to the alarm value, the value chief, the operation manager, and the unit load should be reduced.

The main functions of the steam turbine shaft seal are:

1. Due to the unequal atmospheric pressure in the cylinder and the outside atmosphere, it will inevitably cause the steam in the cylinder or the air outside the cylinder to leak out or leak in along the radial gap between the main shaft and the cylinder, and heat the journal or make the steam enter the bearing chamber, causing the deterioration of oil quality, leaking air and destroying the vacuum, so that the rotor passes through the cylinder at both ends are equipped with steam seals, the high-pressure shaft seal is used to prevent steam from leaking out of the cylinder, and the low-pressure shaft seal is used to prevent air from leaking into the cylinder.

2. During the operation of the steam turbine, there must be a part of the steam leaking from the shaft end to the atmosphere, which also affects the working environment of the steam turbine generator.

3. Prevent the leakage of steam and valve stem in the cylinder from leaking outward, polluting the environment of the steam turbine room and the lubricating oil quality of the bearing. Prevent high-temperature steam from flowing through the large shaft of the steam turbine during normal operation of the unit, causing it to heat up, thereby causing the bearing to overheat.

4. During the whole hot shutdown process of the steam turbine shutdown and the condenser needs to maintain the vacuum, prevent air from leaking into the steam turbine, accelerate the internal cooling of the steam turbine, and cause the large shaft to bend.

A shaft is a friction seal or stuffing box to prevent fluid leakage between the shaft and bearing of a compressor or other fluid transfer device, and a sealing device to prevent leakage between the shaft and housing of a pump. Commonly used shaft seal types are packing seals, mechanical seals and power seals.

Prevents steam from the high-pressure part from leaking outward, and air from the low-pressure part from leaking into the cylinder.

The kinetic energy of the steam turbine rotor is transferred by steam, and during normal operation, the steam turbine rotor is rotating, while the cylinder is stationary. In order to prevent a large amount of steam from leaking out of the high-pressure cylinder and a large amount of air from the vacuum part of the low-pressure cylinder, and improve the thermal efficiency and safety of the unit, high and low pressure shaft seals are placed at the front and rear ends of the cylinder.

At the place where the turbine passes out of the cylinder, a shaft seal is set in the gap between the dynamic and static parts to reduce steam leakage, also known as the cylinder end seal. The shaft seal is generally divided into several sections, each section has multiple steam sealing rings, and there is a steam chamber between each section, and the steam leaking into the chamber is evacuated or steam is supplied to the chamber through the pipeline. The types of steam turbine shaft seals include traditional toothed seals, Bryden seals, and honeycomb seals, which have thicker steam seal teeth and large steam seal gaps, and in order to greatly reduce the amount of steam leakage, there are several small gap steam seals in the near future, such as brush steam seals, soft tooth steam seals, and elastic tooth steam seals.

The shaft seal of a steam turbine is also called a steam seal.

There are many kinds of steam seals, and the shaft seals you say refer to the shaft end steam seals.

It is divided into high-pressure end and low-pressure end, and the high-pressure end is to reduce the leakage of steam and maintain the environment of the workshop. The shaft seal at the low pressure end is to prevent air from leaking inward and maintain the vacuum.

The main function is to prevent the steam in the high-pressure part from leaking outward, and the air in the low-pressure part from leaking into the cylinder. In layman's terms, it is to isolate the steam engine from the outside world and seal the steam engine.

EliminationThermal bending of the rotor,DecreaseThe temperature difference between the upper and lower cylinders and the function of reducing the punching torqueCheckWhether there is friction between the turbine and whether the lubricating oil system is working normally.

The so-called "cranking" refers to the use of manpower to rotate the motor several times before starting the motor, so as to judge whether the load driven by the motor (i.e., the mechanical or transmission part) is stuck and the resistance increases, so that the starting load of the motor will not become larger and damage the motor (i.e., burn out). Therefore, generally after stopping for a shift (8 hours), when the motor is started again, it is necessary to crank the car.

1. Establish oil film lubrication for each bearing of the steam turbine to reduce the dry friction or semi-dry friction between the journal and the bearing pad and protect the journal from damage.

2. While ensuring that the rotor is evenly heated or cooled, the stirring effect of the rotor on the steam in the cylinder is strengthened, and the temperature difference between the upper and lower cylinders and the resulting thermal deformation and thermal stress are reduced. However, the disadvantage of high-speed crank is that the starting torque is large, and in order to reduce the torque, the top axle oil system is usually used.

3. When the steam turbine is rolling, it can reduce the inertness of the rotor and reduce the impact force of the blades. During overhaul, turning is used, and the excitation electromechanical brush slip ring can also be turned.

1. After the unit is stopped, the rotor rotates continuously to avoid the rotor bending caused by the temperature difference between the upper and lower cylinders caused by the natural cooling of the cylinder.

2. The unit rushes the front disc car to make the rotor rotate continuously to avoid the rotor bending caused by the temperature difference caused by factors such as valve leakage and steam seal and steam supply. At the same time, check whether the rotor has bent and whether there is friction in the moving parts.

3. The unit must be in the state of cranking to be able to rush, otherwise the rotor will be washed in the stationary state due to too much friction, which will lead to the damage of the bearing.

4. A long period of continuous cranking can eliminate the non-permanent bending caused by the long-term shutdown and storage of the unit or other reasons.

There are many functions, the most basic of which is to prevent the shaft from bending.

The function of the top shaft oil pump of the steam turbine is to prevent damage to the steam turbine and reduce the cranking power of the steam turbine.

The oil source of the top shaft oil pump comes from the lubricating oil behind the oil cooler, and the pressure is about that, which can effectively prevent the oil pump from absorbing air erosion. The oil is coarsely filtered through a 32 m automatic backwash filtration unit.

Then through the 25 m double-barrel filter into the top shaft oil pump oil inlet, after the oil pump is pressurized, the oil pressure at the outlet of the oil pump is, the pressure oil enters the diverter through the single-cylinder high-pressure filter, through the check valve, the throttle valve, and finally enters the bearings.

By adjusting the throttle valve, the amount of oil and oil pressure entering each bearing can be controlled, so that the jacking height of the journal is within a reasonable range (theoretical calculation, the jacking oil pressure of the journal is 12 16MPa, and the jacking height is greater than. The oil pressure at the outlet of the pump is regulated by the relief valve.

In order to control the operation of two pumps, switch and prevent pump suctioning damage, the inlet and outlet pipelines of oil pump are equipped with pressure switches, and when the oil pressure at the inlet of the oil pump, the pressure switch at the inlet of the oil pump is turned on (on), indicating that the suction filter screen is blocked; When the oil pressure of the outlet pipeline of the pump is on, the pressure switch on the outlet pipeline is turned on (on), and the standby top shaft oil pump should be started.

The oil film has not yet been established at the bottom of the shaft diameter when the steam turbine is from the stationary state to the start, and the oil film at the bottom of the shaft diameter is established when the top shaft oil system is started, and the shaft diameter is lifted to reduce the friction between the shaft diameter and the bearing pad, and at the same time, the crank device can smoothly rotate the bearing, which can reduce the power of the crank motor, save the power of the plant, and reduce the rotating torque of the punching car and save steam.

The steam turbine has a coaxial oil pump that provides lubricating oil to the bearings. However, in the process of starting and stopping the steam turbine, the coaxial oil pump decreases with the rotation speed, and the oil pressure also decreases, which cannot serve the purpose of supplying oil to the steam turbine bearing. Therefore, the top shaft oil pump is set up, which runs when the steam engine starts and stops, and provides qualified oil pressure lubricating oil to the steam turbine bearing, and the lubricating oil will slightly jack up the steam turbine rotor and form an oil film around the bearing, so it is called the top shaft oil pump.

During the cranking, lubrication is also provided by the top axle oil pump.

The function of the top shaft oil pump is to jack up the large shaft and establish the oil film to prevent the occurrence of accidents due to excessive weight of the shaft system, damage to the oil film and damage to the bearing pad in the case of rotor rotation.

The function of the AC and DC seal oil pump is to provide airside sealing oil to the generator to prevent hydrogen leakage inside the generator.

As the name suggests, the top shaft oil pump is the top shaft, which is mainly used before starting and stopping the car and using the top shaft oil pump to pump the oil to the bearing box, and jacking the large shaft to a certain height to avoid friction when cranking.

Jack the large shaft of the steam turbine to prevent the lower bearing from wearing at low speed, but the oil pressure of the top shaft should not be too high, otherwise the upper bearing will wear.

It can play a role in reducing axial thrust.

A steam turbine is a rotating power machine that converts the energy of steam into mechanical work. The version is also known as the steaming power steam turbine. It is mainly used as a prime mover for power generation, and can also directly drive various pumps, fans, compressors and ship propellers.

It can also use the exhaust steam or intermediate steam extraction of the steam turbine to meet the heating needs of production and life.

What do you mean by vapor balance?

Yes? Is it a source balance piston? If so, it is to reduce the axial thrust. If you're talking about uniformity.

The steam intake is made of circumferential steam intake and other structures to make the steam intake uniform.

The headless deaerator has a steam balance pipe to prevent the water from backing up to the pumping steam when the load is suddenly shaken. There are also some heater vapor balance, shaft seals or something, and some ordinary deaerators also have them, which are to balance the vapor pressure.

Does it mean balancing the piston?

1. The function of the shaft seal at the low pressure end of the condensing steam turbine is to prevent the outside air from leaking into the cylinder, thereby destroying the vacuum of the condenser, increasing the exhaust pressure of the steam turbine and reducing the economy of the unit. In order to improve the steam leaking from the high-pressure end and prevent the outside air from leaking from the low-pressure end, the steam turbine is equipped with a steam sealing system. It is a schematic diagram of the steam turbine shaft end sealing system.

Here's how it works. In order to reduce this part of the loss, the shaft seal at the high-pressure end is divided into a number of sections, and a certain empty chamber is left between each section, and the steam leakage in these empty chambers is led to different places according to the level of its pressure respectively to be utilized, so as to improve the economy of the unit. Small steam turbines generally seal the steam leakage at the high-pressure end through the pipeline, and the rest of the small amount of steam leakage is discharged to the atmosphere by the signal pipe after passing through several shaft seals.

During operation, the shaft seal can be monitored by observing the steam emitting from the signal tube.

2. Although the low-pressure end is equipped with a shaft seal, it cannot avoid the leakage of outside air, so it is necessary to use the steam with a pressure slightly higher than the atmospheric pressure to seal it to prevent air leakage. The steam used for this part of the sealing is from the high-pressure end shaft seal through the pipeline, and a part of the steam flows into the low-pressure cylinder after passing through part of the shaft seal; The other part flows out along the shaft seal gap and is finally discharged to the atmosphere through the signal tube.

3. When the steam turbine is working normally, in addition to the introduction of low-pressure end shaft seal steam leakage, the excess part can be sent to the shaft seal heater through the pipeline to heat the condensate, and part of the heat of the shaft seal steam leakage can also be directly introduced into the condenser. During the start-up and shutdown of the steam turbine, if there is no steam at the high-pressure end shaft seal, the new steam that has been decompressed and depressurized should be sent to the high-pressure and low-pressure end shaft seal at the same time.

The working principle of the shaft seal system of the steam turbine, when the unit is in normal operation, the steam source of the shaft seal system comes from the second stage of steam extraction, and when the unit starts and stops or is low load, because the second stage steam extraction pressure is too low, the new steam is used to supply steam to the shaft seal system, in order to maintain the stability of the steam supply pressure, the pressure regulator is realized by the pressure regulator on the equalizing box, when the pressure of the equalizing box is too high, the pressure regulator acts, reducing the amount of steam entering the equalizing box, if it is still too high, part of the steam will enter the condenser; If the pressure of the equalizing chamber is low, the opposite operation is carried out to keep the pressure of the equalizing chamber stable.