JPS5943906A - Protective trip device for rotary machine - Google Patents

Abstract

PURPOSE:To have automatic stop of a rotary machine at the time of shaft breakage by furnishing pressure switches with different set values in a discharge system of a main oil pump mounted on the shaft of the rotary machine and by actuating the emergency stop device of the same when the discharge pressure sinks below the set pressure values of both switches. CONSTITUTION:Two pressure switches 1, 2 are installed at the discharge oil pipe 9 of a main oil pump 10 driven by the main 17 of a turbine 19. These switches are so set that one 1 will be off with the oil pressure below P1 while the other 2 off with the oil pressure exceeding P3, where P3 is higher than P1, and when both switches are off, a relay 20 is actuated to put an emergency shutoff valve 21 in service in order to close a stop valve 22. Off conditions of the two switches are normally not overlapped, but an abrupt drop of the oil pressure because of breakage will not permit the sensing pressure of the switch to sink so quickly through the action of an orifice 8 and oil chamber 7, so that both switches are turned off and a relay 21 is actuated to cause emergency stop of the turbine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a main oil pump of a rotating machine, and is particularly suitable for a machine in which a rotating machine shaft and a main oil pump shaft are connected. Relating to a protective device for stopping.

The rotating shaft of a steam turbine usually has one or more main axles having impellers and a detection part for a rotation speed control mechanism.
It consists of several auxiliary axles.

The auxiliary axle is located at the tip of the steam turbine and is directly connected to the main axle.

The auxiliary axle is equipped with a rotation speed control detection unit, an overspeed prevention device, a main oil pump driven by the axle, etc. The auxiliary axle is equipped with these important devices, which can be called the brain of the turbine. There is.

That is, if the auxiliary axle were to break for some reason, the connection with the main axle would be severed, and the steam turbine would face an extremely serious crisis of being unable to control its speed.

If the auxiliary axle breaks, the connection with the main axle is severed.

That is, the main axle continues to rotate (as mentioned above, there is no longer a function to control the rotation), while the auxiliary axle immediately stops. Naturally, such a stop of the auxiliary axle means that the main oil pump stops functioning, and the pump discharge/-E force suddenly increases by K14'F, making it impossible to operate the rotating machine.

The object of the present invention is to detect the J loss of the auxiliary axle as a drop in the main oil pump discharge pressure, and to voluntarily stop the rotating machine, which is a steam turbine, to protect the main oil pump of the rotating machine. It is without providing.

In the present invention, a plurality of pressure gases and f-ts are installed in the main oil pump discharge line, and furthermore, the set values of these pressure gases and f-ts are set to be mutually lower than the set value. This system activates the emergency stop device for the rotating machine when In addition, an oil chamber is provided in the lamina of one of the multiple switches, so that if there is a sudden change in pressure, the change will be detected by the pressure gauge with an appropriate time delay. . When the rotary machine is normally stopped and the main oil pump is also stopped, the drop in the oil discharged from the main oil pump is gradual and the pressure switch settings are different, so the pressure switch operations do not overlap. On the other hand, if the main oil pump discharge pressure suddenly decreases in the event of an abnormality such as a broken auxiliary axle, the pressure detection unit equipped with an oil chamber will be slow to detect the low pressure, i'L, and as a result, Since the operation of multiple pressure switches with different set values stagnates, it is possible to detect a sudden pressure drop.When this sudden pressure drop above the main oil pump discharge 11 is detected, the rotating machine It was designed to make an emergency stop.

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram in which safe equipment is added to the present invention. During normal operation, the main oil pump 1o is driven by the main axle 17.
The oil pipe 9, check valve 15 and oil pipe 16 are driven by high pressure oil (for control equipment) and low pressure r'tll (bearing).
(for national information). The oil turbine 14 is driven by oil discharged from the main oil pump °10.

The high-pressure oil that has been consumed in the drive is converted into low-pressure discharge oil from the oil turbine 14.

A booster pump 12 directly connected to an oil turbine 14 through a coupling 13 sucks up oil from a main oil tank 2 and supplies it to the main oil pump 10 via an oil pipe 11. Oil pipe 9 between main oil pump °10 and check valve 15
Two pressure switches are provided on the top. These detect the oil pressure in the oil pipe 9 via the oil pipes 5 and 6 and the stop valves 3 and 4 for pressure adjustment, respectively.

A speed governor 18 is installed at the tip of the auxiliary shaft that drives the main oil pump, and opens and closes a valve 20 that controls the amount of working fluid (steam in the case of a steam turbine) flowing into the turbine 19 . If the auxiliary shaft breaks, this governor will act as if the rotational speed of the rotating shaft had become zero, and the valve 2 would be activated to bring the rotational speed to the target value.
This acts in the direction of opening zero, causing the rotating shaft to overspeed and become dangerous. The signals of pressure switches 1 and 2 are relay 20
The emergency shutoff valve 21 is operated under the operational reliability of the relay shown in FIG. As a result, turbine 19
valve 20 is closed and the turbine is stopped. In addition, a stop valve 22 is usually installed upstream of the valve 20, but in that case, when the emergency shut-off valve 21 operates like the valve 20,
The stop valve 22 also closes quickly.

In FIG. 2, the pressure switch 1 (PS-1) has a characteristic that the contact OFF condition is canceled when the oil pressure is 22 or more, and the contact OFF condition is established when the oil pressure is less than P1. On the other hand, the pressure switch 2 (PS-2) has a contact of OFF when the oil pressure is 24 or higher.
It has the characteristic of establishing the condition and releasing the contact OFF condition when the oil pressure is below P3. Relay X is energized and brings the turbine to an emergency stop only when a condition is established in which the contacts of these pressure switches are simultaneously turned off.

When the turbine is started, the main oil pump discharge oil pressure also increases as the turbine speed increases. When the oil pressure rises to 12 or more, the OFF condition is released. When the oil pressure rises to 24 or more, pressure switch 2 (PS-
2) establishes the OFF condition.

During normal turbine operation, the oil pressure indicates P. During this time, the pressure switch 2 (PS-2) maintains the 01''F condition. When the turbine normally stops, when the oil pressure drops to below P3, the pressure switch 2 (PS-2) releases the OFF condition.

When the oil pressure drops below Pl, pressure switch 2 (PS-
2) establishes the OFF condition again.

That is, during normal startup, operation, and shutdown, the OFF conditions for the two types of pressure switches 1 and 2 are established at the same time, and it is impossible for relay X to be energized.

Assume that the auxiliary shaft breaks during normal operation. The main oil pump 10 immediately stops and the oil pressure in the oil pipe 9 drops rapidly. When the oil pressure drops below I) 3, the pressure cass isochi 2
(PS-2) cancels the OFF condition. However, the presence of oil prefilled in the oil chamber 7 delays the release of the 0FFIS condition. On the other hand, since the oil pressure has dropped to below PI, an OFF condition is immediately established for pressure switch 1 (PS-1).

Due to the delay in releasing the OFF'lZ condition in the pressure switch 2, both OL''F conditions are satisfied and the relay X is energized.

In order to expand the range in which this excitation signal is valid and ensure excitation, it is effective to further delay the arrival time of contact P3 of pressure switch 2 (PS-2). An orifice 8 is provided between the oil pipe 17 and the oil pipe 6 as a mechanical means. It is also possible to install a timer (in Figure 2) as an electrical means (the area enclosed by the dotted line).

The present invention is a simple device that detects a sudden drop in the main oil pump discharge pressure and implements an emergency stop of a rotating machine such as a turbine, and also provides the following effects. In the present invention, the first pressure switch (PS-1) is turned off in the low main oil pump discharge pressure region, and the second pressure switch (Its-2) is turned on in the same low region.

Therefore, when both are turned off, the turbine is brought to an emergency stop. Also, the main oil pump has completely stopped and the main oil pump discharge is zero.
The turbine emergency stop signal is automatically canceled and the system enters a reset state. There is no need to install a separate reset switch.

In addition, in the embodiment of the present invention, when the two switches are OFF, the turbine is brought to an emergency stop, so that in the event of an accident such as a power failure of the pressure switch, the turbine will not be brought to an emergency stop, and the operation will be performed on the safe side. Become.

That is, it has the function of FAIL-8AF'H.

Therefore, according to the present invention, it is possible to immediately detect failure of the axle on which the main oil pump of the steam turbine is installed and automatically stop the rotating machine.
It is effective in preventing problems.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing a protective trip device for a steam turbine according to an embodiment of the present invention, and FIG. 2 is an operating membrane in the protective trip device shown in FIG. 1. It is an explanatory view showing operation and non-operation states of two types of pressure switches with different fixed values. 10... Main oil pump, 17... Main axle, 1, 2...
・Pressure switch, 7...oil chamber, 8...orifice,
20... Lee 2 [

Claims (1)

[Claims] 1. A plurality of pressure switches having different pressure setting values are installed in the discharge system of a main oil bonder provided on the main oil pump shaft of a rotating machine, and the discharge pressure of the main oil pump is equal to both pressures. A protective trip device for a rotating machine, characterized in that when the pressure drops below each pressure setting value of the switch, the pressure switch is operated to activate an emergency stop device for the rotating machine and stop the operation of the rotating machine. 2. A protective trip device for a rotating machine according to claim 1, characterized in that an oil chamber is provided in one system of the pressure switch, and an orifice is provided in the system. 3.% Allowance The protective trip device for a rotating machine according to claim 1, characterized in that an oil chamber is provided in one system of the pressure switch, and a timer means is provided in this one switch.