JPH0281903A - Turning operation method for steam turbine - Google Patents

Abstract

PURPOSE:To enable the prevention of the detachment of a gear during a continuous turning by detecting the governor valve opening angle and rotor rotation number to release the excitation of an air cylinder. CONSTITUTION:When a turning motor 12 is rotated by a turning device automatic signal 8, a governor valve full-closing signal 10 is denied by a NOT circuit NOT3, and a wipe out WO3 remains as it is. Thus, an air cylinder 4 remains excited during a continuous turning, and a turning gear 1 is forcedly engaged with a rotor gear 2. The turning gear 1 is difficult to detach from the rotor gear 2 even when the torque is reduced by the fluctuation of the rotation torque on the rotor side, and a smooth turning operation can be conducted. On the other hand, when the governor valve is opened and the governor valve full-closing signal 10 is disappeared, the wipe out WO3 is moved by the hot circuit NOT3 to make the air cylinder 4 unexcited, and the turning gear 1 is detached.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention provides a steam turbine for commercial and industrial use,
This invention relates to an improved method of turning a steam turbine to remove rotor eccentricity.

(Prior Art) A steam turbine is a machine that rotates at a very high speed, and is designed so that the gap between a rotating part and a stationary part is made as small as possible to prevent performance deterioration. Therefore, if the rotor increases its rotation while remaining eccentric, contact between the rotating part and the stationary part may occur, resulting in excessive vibration.

One of the causes of rotor eccentricity is that when the turbine is stopped and the rotor is placed stationary in a temperature difference between the upper and lower halves of the casing, the temperature between the upper and lower surfaces of the rotor increases. Eccentricity will occur due to the difference. Therefore, when stopping the turbine or before starting it, be sure to perform a so-called turning operation in which the rotor rotates at low speed (2 to 10 rpm 8 degrees) for a predetermined period of time to reduce the temperature difference between the upper and lower halves of the casing and the rotor. It is necessary to make it uniform and remove eccentricity.

Turning after the turbine has stopped and before starting is one of the most important operational operations, but steam turbines are generally equipped with a turning device consisting of a dedicated motor and reduction gear. Turning is performed by meshing the gear on the turning device side and the gear on the rotor side.Also, when the turning operation is finished and the turbine speed is increased, the turning gear and the gear on the rotor side are quickly connected. Since it is necessary to release the turning device at a certain time, the turning device is generally equipped with a weight to automatically release the turning device.

Therefore, during continuous turning, the gear on the rotor side and the turning gear are maintained in mesh by transmitting torque to the rotor side, and when the rotor side is rotated by steam, there is no need to transmit torque from the turning gear side. It is a so-called automatic fitting/disengaging type that detaches by the action of a weight.

(Problem to be solved by the invention) This method is very effective for protecting the turning device, but on the other hand, the gear engagement during turning depends only on torque transmission, so the rotor When the rotational torque of the rotor decreases due to slight torque fluctuations or the inflow of a small amount of steam.

This also includes the possibility that the turning gear will disengage and the turning operation will be interrupted. In this case, if the rotor stops, the coupling block of the turning gear works again to reconnect the turning gear, but if this happens more frequently, it is undesirable because the shock caused when the gears are connected may cause damage to the gears.

An object of the present invention is to provide a turning operation method for a steam turbine that can prevent gear disengagement even during continuous turning.

[Structure of the invention]

(Means for Solving the Problems) The steam turbine turning operation method of the present invention connects a turning gear driven by a turning motor to a rotor gear on the steam turbine rotor side by excitation of air supply to an air cylinder. Equipped with a turning device that separates the turning gear from the rotor gear using a weight when air is removed from the cylinder without excitation, and during turning operation of the steam turbine, a turning device automatic operation signal, a turbine stop signal, a steam turbine control valve fully closed signal, and a bearing hydraulic pressure are provided. When the normal signal is established, the excitation of the air supply to the air cylinder is commanded, and the turning motor is commanded to start, and the excitation of the air cylinder is continued, and when the steam turbine speeds up, there is no signal for fully closing the regulator valve. The feature is that the air is removed from the air cylinder to make it non-excited.

(Function) In the present invention, during turning operation of the steam turbine,
When the turning device automatic signal, turbine stop signal, regulating valve fully open signal, and bearing oil pressure normal signal are established, the turning motor starts, drives, and restarts. During this time, the air cylinder receives air supply and is energized, and the turning gear is activated. Securely connects to the turbine rotor gear. The excitation of the air cylinder continues during turning operation to prevent the turning gear from disengaging. At the same time as the turbine speeds up, the air cylinder is de-energized, and when the rotational speed increases, the automatic engagement and disengagement mechanism safely disengages the gear.

(Embodiments) The present invention will be described below with reference to embodiments shown in FIGS. 1 to 5. First, FIGS. 4 and 5 show an automatic insertion/removal type turning device to which the steam turbine turning operation method of the present invention is applied. In FIGS. 4 and 5, for turning operation, turning gear 1 and rotor gear 2 mounted on the rotor side are engaged, and the rotation of the motor is decelerated by gears in the turning device. is configured to transmit torque from turning gear 1 to rotor gear 2.

This turning gear 1 is connected to a carrier 3 as shown in FIG.
When a turning operation is not performed, the carrier 3 is moved downward by a weight 7 provided at the tip of the carrier as shown in FIG. 5, and the gear is disengaged. Therefore, when the rotor is rotating at high speed, the gear is always disengaged due to the action of the weight 7,
The gears will not contact each other and be damaged, and the turning motor will not rotate at high speed while the gears are still meshed.

Now, when the steam turbine is stopped or before starting, it is necessary to engage the gears and perform turning operation to remove eccentricity, but at this time, by exciting the air cylinder 4, the toggle mechanism 5 The turning gear 1 and the rotor gear 2 are brought into engagement by lifting the rotating gear upward via the attached shaft 6.

Now, the steam turbine turning operation method according to the present invention using the gear coupling device configured as described above is carried out by the block control system shown in FIG. 1 and the sequence diagram shown in FIG. 2. That is, in FIG. 1, for example, when the steam turbine is stopped, if there is a turning device automatic signal 8, the turbine rotor is stopped by the zero speed switch 9.
When detected, the OR circuit ORY outputs an output, and the AND circuit AND outputs the control valve fully closed signal 10.

In response to the output of the AND circuit AND1, the output of the OR circuit OR2 causes the AND circuit AND2 to output an output in response to the turning device automatic signal 8, which becomes a starting signal for the turning motor 12.

The activation signal from the AND circuit AND is sent to the AND circuit AND via the timer 15 and the wipeout WO1 where the passing signal is cut off when the signal indicated by the arrow is input.

is input. This AND circuit AND is this origin 1
It receives and outputs the signal and the bearing oil pressure normal signal 11 to start the turning motor 12. The NOT circuit NOT creates a stop circuit. Also, the output side of timer 15 and wipeout WO
1, a wipeout W02 and timer 16 circuit is constructed.

By the way, before starting the turning 12, the turning gear 1 of the gear coupling device shown in FIG. 4 must be engaged with the rotor gear 2. This time adjustment is done by timer 15.
and 16. That is, the output signal from the AND circuit AND is input to the OR circuit OR3, and further passes through wipeout Wo3 to become an excitation signal for the air cylinder 4 shown in FIGS. 4 and 5. Create a non-excitation circuit with the knot circuit N0T2.

Upon receiving this excitation signal, the air cylinder 4 enters the ON operation from OFF according to the sequence shown in FIG. 2, lifts the carrier 3 shown in FIGS. 4 and 5 upward, and engages the turning gear 1 with the rotor gear 2. shall be. At this time, gears 1 and 2 may not mesh completely, so
As shown in FIG. 2, the turning motor 12 is driven by the timers 15 and 16, and the turning gear 1 is completely engaged with the rotor gear 2. This combined signal of both gears 1 and 2 is input to the AND circuit AND, and timer 17
In response to the output from the AND circuit AND, the output from the AND circuit AND commands the wipeout Wo2 to turn on the turning motor 12 again and restart it.

Therefore, in the steam turbine turning operation method of the present invention, even after the turning motor 12 is driven according to the above-described operation order and then restarted, the excitation of the air cylinder 4 is continued during the turning operation. The air cylinder 4 is de-energized under the condition that the regulator valve lO is open, that is, when the steam turbine is operating at increased speed or at the rated rotational speed.

That is, in FIG. 1, the control valve fully open signal 10 is input to the wipeout WO3 via the AND circuit IAND and the NOT circuit N0T3. This is because while the adjusting valve fully closed signal 10 is rotating the turning motor 12 with the turning device automatic signal 8, the adjusting valve fully closed signal 10 is negated by the knot circuit NOT, and the wipeout W○ remains as it is. The air cylinder 4 remains energized, and the air cylinder 4 of FIG. 2 also remains in the ON state.

This maintenance of the ON state of the air cylinder 4 is possible because the air cylinder is excited even during continuous turning, so the carrier 3
This means that the turning gear 1 and the rotor gear 2 are forcibly engaged by lifting the entire body. therefore,
Even if the torque decreases due to fluctuations in the rotational torque on the rotor side, the turning gear 1 is difficult to separate from the rotor gear 2, and smooth turning operation can be performed.

Furthermore, when the steam turbine is started up when the turning gear 1 separates from the rotor gear 2, the control valve opens and steam flows into the steam turbine. Therefore, when there is no control valve full open signal 10, the wipeout WO3 is operated by the NOT circuit NOT, and the NOT circuit NOT.

After that, the air cylinder 4 becomes non-excited, and the turning gear 1 can be safely disengaged by using the automatic engagement/disengagement function using the weight 7 of the carrier 3 as in the conventional case.

In another embodiment shown in FIG. 3, the control valve fully closed signal 1
An OR circuit OR4 is provided on the output side of the NOT circuit NOT of the 0 signal circuit, and the input of this OR circuit OR has a turbine rotation speed that is the output of the NOT circuit NOT and the turning rotation speed plus several rpm. The output of the OR circuit OR1 is given as an output of 19 or more, and the output of the OR circuit OR1 is commanded to the wipeout W03.

In this other embodiment, a function is added to safely separate the turning gear 1 from the rotor gear 2, and the control valve lO
The air cylinder 4 is de-energized and de-energized when the rotation speed of the turbine reaches a certain specified value in addition to when the cylinder 4 is opened.

[Effect of the Invention J As described above, in the present invention, even more stable turning operation can be performed by using the air cylinder, which was used only for gear meshing in the conventional technology, also during continuous turning.

It can reduce the possibility of turning gear damage and increase reliability. Furthermore, if the excitation of the air cylinder is always released by detecting the opening degree of the adjusting valve, the rotation speed of the rotor, etc., safe turning operation can be realized without impairing the automatic engagement/disassembly function.

[Brief explanation of the drawing]

FIG. 1 is a block control diagram for explaining the steam turbine turning operation method according to the present invention, FIG. 2 is a sequence diagram for explaining the present invention in detail, and FIG. 3 is a diagram showing another embodiment of the present invention. A block W diagram for explanation, FIG. 4 is a configuration perspective view showing the tanning device used in the present invention, and FIG.
The figure is a side view of the turning device of FIG. 4. 1... Turning gear 3... Carrier 5... Toggle mechanism 7... Weight 2... Rotor gear 4... Air cylinder 6... Mandrel agent Patent attorney Nori Chika Ken Yudo Daishimaru Ken

Claims (1)

[Claims] A turning device is provided in which a turning gear driven by a turning motor is coupled to a rotor gear on a steam turbine rotor side by excitation of air supply to an air cylinder, and the turning gear is separated from the rotor gear by a weight when air is removed from the air cylinder without excitation. During turning operation of the steam turbine, a turning device automatic operation signal, a turbine stop signal, a steam turbine control valve fully closed signal, and a bearing oil pressure normal signal are established to command the excitation of air supply to the air cylinder, and the turning operation is performed. Commands the motor to start and continues energizing the air cylinder,
A turning operation method for a steam turbine characterized in that when the steam turbine speeds up, air is removed from an air cylinder to make it non-excited without a signal to fully close a control valve.