JPS5836209Y2 - Seal oil supply device for rotating electric machines - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sealing oil supply device used for a shaft seal of a rotating electric machine in which a cooling gas such as hydrogen gas is sealed.

For example, in hydrogen-cooled turbine generators, etc., the rotating shaft is a bearing part, and the seal that passes through the stationary part continuously supplies sealing oil at a pressure slightly higher than the hydrogen gas inside the machine, preventing gas leakage to the outside of the machine. are doing.

A system diagram of a sealing oil supply system for a hydrogen-cooled turbine generator is shown in FIG.

In the figure, 1 is a turbine generator, 2 is a rotating shaft, 3 is a pair of bearings on both sides that support this rotating shaft (one side is shown in cross section in the figure), and 4 is a shaft penetrating through the turbine generator 1. This is a sealing part installed in the aircraft to prevent hydrogen gas inside the aircraft from leaking into the atmosphere outside the aircraft, and as shown in the figure, three systems of sealing oil are supplied.

4a is a seal ring of the sealing portion 4, which is kept in a floating state by sealing oil.

5 is a sealed oil pump on the hydrogen side (inside the machine), and AC motor 6
It is directly connected to and is in constant operation, and sealing oil is supplied under pressure to the hydrogen side (inside the machine) of the sealing parts 4 on both sides through a conduit 8 via a check valve 7.

9 is a return pipe that flows down from the hydrogen side of the sealing parts 4 on both sides and returns the accumulated sealing oil; 10 is a return pipe that stagnates the discharged sealing oil from this return pipe, separates the mixed hydrogen gas in the upper part, and is a hydrogen gas cutoff tank that stores sealing oil, and the sealing oil is sucked into the sealing oil pump 5 from the lower part.

Reference numeral 11 denotes a sealing oil pump on the air side (outboard side of the machine), which is directly connected to the AC motor 12 and constantly operated. Press-fit and supply.

15 is an emergency sealed oil pump on the air side, and a DC motor 16
The sealed oil pump 11 side is switched and operated in the event of an accident.

17 is a check valve, 18 is a sealing oil float pump, which is directly connected to the AC motor 19 and operates, and supplies sealing oil to the air side ends of the sealing parts 4 on both sides through conduits 20 and 21, and the sealing parts rotate 40 times. A seal ring 4a surrounding the shaft 2 is maintained in a floating state.

Next, 22 is a lubricating oil pipe, through which lubricating oil is sent from a lubricating oil supply system (not shown) in the direction of arrow A, to the bearings 3 on both sides.
supply to.

23 is an oil drain pipe that discharges the lubricating oil flowing down from the bearing 3 and the air side sealing oil flowing down, and 24 is a loop that stagnates the oil from this oil drain pipe and discharges the mixed hydrogen gas upward to remove it. In the seal tank, the lubricating oil is returned to the main oil tank (not shown) through a return pipe 25 in the direction of arrow B.

26 is a return pipe that returns the seal oil from the lower part of the loop seal tank 24 to the seal oil pump 11 side; 27 is a differential pressure regulating valve inserted between the conduit 14 and the return pipe 26; The supply pressure of sealing oil by the extraction pipe 29 led from the upper side of the conduit 14 increases by a predetermined pressure difference with respect to the gas pressure from the in-machine hydrogen gas side via the drained oil by the led extraction pipe 28. Adjust the pressure of the sealing oil on the conduit 14 side.

The figure shows an example of a double-flow system for supplying the sealing oil to the sealing part 4, in which the hydrogen side and the air side are supplied by separate pump systems, but the supply circuit for the hydrogen side sealing oil has a pressure equalizing valve. (not shown) is provided so that the oil pressure is the same as that of the air side sealing oil.

Therefore, the supply pressure of the sealing oil is extracted through the extraction pipe 29.

Furthermore, hydrogen gas pressure from the inside of the turbine generator 1 is applied to the hydrogen side of the sealed portion 4 and the return pipe 9 and hydrogen cutoff tank 10 from this side.

Therefore, waste oil on the hydrogen side is introduced into the extraction pipe 28 branched from the lower surface of the horizontal portion of the return pipe 9, but the pressure is only the hydrogen gas pressure from inside the machine, and this gas pressure is extracted. It will be.

In this way, the pressure difference adjustment valve 27 is adjusted to maintain a predetermined differential pressure that is slightly higher than the predetermined gas pressure of the hydrogen gas inside the machine, and the gas inside the machine is sealed. I have to.

A low differential pressure detector 30 is inserted between the extraction tubes 28 and 29 and is activated when the differential pressure between the two becomes lower than a set value.
The system detects the pressure difference between the pressure of the hydrogen gas extracted from inside the machine and issues a detection signal when the sealing oil supply pressure on the high side drops and the pressure difference becomes lower than the set value.

Reference numeral 31 denotes a replenishment pipe that replenishes sealing oil from the conduit 14 when the oil level in the hydrogen gas cutoff tank 10 falls below a set height, and 32 refers to a supply pipe that replenishes sealing oil to the return pipe 26 when the oil level in the hydrogen gas cutoff tank 10 rises above the set height. 33 is a check valve.

In the above device, seal oil is supplied to the hydrogen side and air side of the sealer 4 through separate supply systems, and the emergency seal oil pump 1
5 is installed in parallel only to the air-side seal oil system due to equipment costs.

The air side sealing oil pump 11 and the emergency sealing oil pump 15 have capacities that are capable of supplying sealing oil for both the hydrogen side and air side systems.

When an accident occurs on the sealing oil pump 11 side and the low differential pressure detector 30 is activated, this signal starts the DC motor 16 and switches the operation to the emergency sealing oil pump 15.

In the conventional sealing oil supply device, when an accident occurs on the sealing oil pump 11 side, only the low differential pressure detector 30 detects, and this operation switches to the emergency sealing oil pump 15.

However, when the AC power supply is lost and the hydrogen side seal oil pump 5 and the air side seal oil pump 11 stop simultaneously, the amount of seal oil required for both systems must be quickly restored.
I couldn't centrifuge it.

This is because after the loss of AC power, the emergency seal oil pump 15 will not start until the seal oil differential pressure drops to a certain extent and the low differential pressure detector 30 is activated, resulting in a prolonged blank period for pump operation. be.

For this reason, the emergency sealing oil pump 15 side is required to have strict starting characteristics, but during the transition period of switching, there is a risk that the required amount of sealing oil will be insufficient and hydrogen gas will leak.

This idea was made in order to eliminate the drawbacks of the conventional devices mentioned above, and in order to eliminate the blank time between the loss of AC power and the activation of the seal oil low difference detector, the power failure detector detects the loss of AC power. When detected, the emergency seal oil pump is started, and in the event of a failure on the air side seal oil pump side without a loss of AC power, the emergency seal oil pump is started by the operation of the seal oil low differential pressure detector, similar to the above conventional system. The purpose is to reliably prevent hydrogen gas from leaking from the sealed part and improve reliability.

A system diagram of a sealing oil supply device according to an embodiment of this invention is as follows:
As shown in FIG. 1, the emergency sealed pump 15 is started not only by the operation of the low differential pressure detector 30 but also by the operation of detecting the loss of AC power by the power failure detector.

This is shown in FIG. 2 as a circuit diagram according to an embodiment of this invention.

Reference numeral 40 denotes an operating circuit power supply line, and a DC power supply, for example, is used so that there is no problem even if the AC power supply fails.

30a is a contact of the low differential pressure detector 30, and when it is activated and closed, the relay 41 is activated.

41a is a normally open contact of this relay for self-holding.

42 is a return button switch.

A power outage detector 43 is provided on the AC power line 50 side of the AC motor 12 of the sealed oil pump 11, and 43a is a normally open contact of this power outage detector.

41 b is a normally closed contact of the relay 41, 51 is an AC motor control circuit, 52 is an electromagnetic switch, 53 is its operating coil, 41 C is a normally open contact of the relay 41, 60 is a DC power line, and 61 is a DC motor control circuit, 62 is an electromagnetic switch,
63 is its operating coil.

In the device of the above embodiment, the contact 41b is normally closed and the AC motor 12 is operated.

When the power failure detector 43 is activated due to a loss of AC power supply or the low differential pressure detector 30 is activated due to a drop in the differential pressure of the sealing oil, the relay 41 is activated and opens the AC motor 12 side, and at the same time starts the DC motor 16. Then, the emergency seal oil pump 15 is switched into operation.

FIG. 3 is a curve diagram showing the amount of oil when the sealed oil pump is switched between normal use and emergency use using the apparatus of the above embodiment.

A1-A2-d2-d3 is the oil flow curve when switching to the emergency seal oil pump 15 due to the operation of the low differential pressure detector 30, and the chain line A1D2'Ds is the oil flow curve when the emergency oil seal is switched to the emergency seal oil pump 15 due to the operation of the power failure detector 43. This is an oil amount curve when switching to pump 15.

A1 and A3 are oil quantity curves until the sealing oil pump 11 stops due to an accident, and D, -D3 and dt d3 are oil quantity curves of the emergency sealing oil pump 15 that has been started and accelerated, respectively.

Here, Qo: Discharge amount of regular and emergency pumps 11 and 15 Ql: Minimum required oil amount on the air side Q2: Low differential pressure detector hydraulic oil amount Q3: Regular oil amount on the air side Q4: Total minimum oil amount for both systems Q5: Total regular oil amount for both systems to: AC power loss time tl: Low differential pressure detector operating time t2: Total regular oil amount return time for both systems t3: Air side regular oil amount recovery time In the diagram, the regular oil pump 11 In the case of a failure in itself, the rotating parts continue to rotate and the amount of oil gradually decreases, but even if the emergency sealed oil pump 15 is started after time t, the pump 11 will not stop rapidly and the oil level will gradually decrease. The decrease in the amount is gradual, and there is also the oil amount due to the hydrogen side sealed oil pump 5, so the total oil amount does not fall below Q4, and this excessive state is passed without any problem.

However, if the AC power supply is lost, the hydrogen side and air side sealed oil pumps 5 and 11 stop.

At this time, in the conventional device, the low differential pressure detector 30 is activated at time t.

Emergency seal oil pump 15 at time t1, one hour after
starts, but the minimum oil amount Q4 cannot be maintained and hydrogen gas leaks from the sealed part.

Therefore, in the device of this invention, the AC power supply is lost (time t).

) At the same time, the emergency seal oil pump 15 is started by the operation of the power failure detector 43, and during the switching transition, the seal oil pump 11 is suddenly decelerating and the emergency seal oil pump 15 is accelerating. The total discharge amount will never be less than the oil amount Q4.

It should be noted that the amount of oil discharged by the pumps 11, 15 that is greater than the required amount is branched back to the suction side.

Further, as a method for supplying sealing oil to the sealing part, in the above embodiment, a double flow type was described in which the sealing oil is supplied through separate systems to the hydrogen side and the air side of the sealing part 4.
This is a single-flow type system in which sealing oil is introduced from the center of the sealing part, the sealing ring is kept in a floating state, and the sealing oil is supplied through a separate system that flows out to the hydrogen and air sides. The supply pressure is taken out, and the hydrogen gas pressure from inside the machine is taken out from the return pipe on the hydrogen side of the sealed part through the extraction pipe, and the pressure difference between the two is detected by a low differential pressure detector, and it is activated when it becomes lower than a predetermined value. It can also be applied when

In the case of this single-flow type, there is only one sealed oil pump powered by AC power.

Further, in the above embodiment, the case of a hydrogen-cooled turbine generator has been described, but it can also be applied to the case of other types of cooling gas or other types of gas-cooled rotating electric machines.

As described above, according to this invention, when AC power is lost, the sealing oil pump powered by AC power is simultaneously switched to the emergency sealing oil pump powered by DC power and started, so the amount of oil required during the switching transition is is maintained, the leakage of in-flight gas is reliably prevented, reliability is improved, and starting control of the DC motor of the emergency seal oil pump is facilitated.

[Brief explanation of drawings]

Figure 1 is a system diagram of a sealing oil supply system for a hydrogen-cooled turbine generator, and Figure 2 shows an embodiment of this invention. Circuit diagram for switching operation with DC motor, Figure 3 is the same as Figure 1.
FIG. 3 is a curve diagram showing the amount of oil when switching the pump shown in FIG. DESCRIPTION OF SYMBOLS 1... Turbine generator, 2... Rotating shaft, 4... Sealing part, 9... Return pipe which is the return side, 11...・・Regular sealed oil pump, 12・・
... AC motor, 14 ... Conduit on the press-in side, 15 ... Emergency seal oil pump, 16 ...
...DC motor, 30...Low differential pressure detector, 4
3... Power outage detector, 50... AC power line.

Claims (1)

[Scope of utility model registration request] In a device that has a regular seal oil pump directly connected to an AC motor and an emergency seal oil pump directly connected to a DC motor, and supplies seal oil to a sealing part that seals the rotating shaft of a rotating electrical machine filled with cooling gas. , a low difference that operates when the pressure difference between the supply pressure of the sealing oil and the gas pressure on the cooling gas side sealed in the rotary electric machine falls below a predetermined value to switch the operation of the sealing oil pump from normal use to emergency use. A sealing oil supply device for a rotating electrical machine, comprising a pressure detector and a power failure detector that operates when the AC power supply of the AC motor is interrupted to switch the operation of the sealing oil pump from normal use to emergency use.