JPS6220604A - Method and device for feeding air to pneumatic bearing - Google Patents

Abstract

PURPOSE:To stably support a pneumatic bearing, by a method wherein gas for low speed supporting during the starting is discharged from a tank previously accumulating a pressure, and when a feed gas pressure is insufficient due to a fluctuation in a load of a turbomachine, a pressure is supplemented from a backup pressurizer to a tank. CONSTITUTION:An operation control device 119 is formed with a control device 121 of a turbo machine 100, an inverter device 120 of a motor, a power source 127 for emergency, and a dynamic brake unit 126. When a starting instruction 122 is inputted to the operation control device 119, a residual pressure P1 in a tank 108 and a set pressure Pa of a pressure switch 116 are in a relation of P1<Pa, the feed of air for the starting is decided to be impossible, and an operation instruction is outputted to a backup pressurizer 117 from the controller 121. Intake air is supplemented to the tank 108 through a filter 18 and a check valve 112. When P1 becomes equal to or higher than Pa, the feed of air for the starting is decided to be possible to open an electromagnetic valve 114, and the air for the starting is fed to pneumatic bearings 107a and 107b to support a rotor 102.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for supplying air to gas bearings of turbomachines that rotate at high speed, such as turbochargers, turbocompressors, and turbine pumps.

[Prior art and problems]

Conventionally, a device for supplying pressurized gas to a bearing from the discharge side of a gas machine via piping is disclosed, for example, in Japanese Patent Publication No. 57-36436.

However, in this conventional example, an auxiliary pressurizing device is installed in the piping to ensure support pressure for the bearing during starting and stopping operations, so the pressure generated during low-speed operation of the gas machine or when switching from low to high speed Fluctuations were transmitted directly to the bearings, resulting in unstable operation and complicated equipment.

In particular, the greatest advantage of gas bearings is their low friction, which is a problem, and they have the disadvantage of requiring long coasting times when stopped, which increases the operating time of the auxiliary pressurizing device.

[Purpose of the invention]

Here, the present invention eliminates the auxiliary pressurizing device that is always activated when starting and stopping the turbomachine, shortens the coasting time when the turbomachine is stopped, and at the same time does not cause pressure fluctuations in the supply gas.
The purpose is to provide a gas supply method and apparatus.

(Summary of the Invention) In order to achieve the above object, the present invention discharges low-speed support gas from a pre-accumulated tank at startup, and when the turbomachine enters steady operation and the discharge pressure reaches a sufficient pressure. , the above tank acts as a surge absorbing tank, and during stopping operation, the turbomachine operates the friction brake, eddy current brake, or dynamic brake to shorten the coasting time. This is a gas bearing air supply method and device that replenishes the tank from an emergency backup pressurizer when the supply gas pressure is insufficient.

〔Example〕

FIG. 1 is a diagram showing a part of an embodiment of the present invention in side cross section and its circuit configuration in blocks.

A start command 122 is sent to the operation/control device 119, which includes a control device 121 for implementing the control flow of the turbomachine 100, an inverter device 120 for driving the motor with an inverter, an emergency power source 127 that is switched in the event of a power outage, and a dynamic brake unit 126. When ゛ is input, backup pressurization 1111 is activated at startup and when pressure is insufficient.
7 through a check valve 112, connected to the discharge side 105 of the turbomachine through another piping through a check valve 110, and further connected to gas bearings 107a and 107b through a solenoid valve 114 through another piping. The residual pressure P1 of the tank 108, which has enough capacity to store the pressure and supply air required to support the bearing during startup and pressure fluctuations, and the set pressure P of the pressure switch 116 .

However, if Pl<Pa, it is determined that starting air supply is not possible, and the control wJ is
When an operation command for the backup pressurizer 117 is issued from the device 121 and the backup pressurizer 117 starts operating, the inhaled gas is removed by the filter 118,
The tank 108 is pressurized and refilled through the check valve 112, and P1
≧P, the backup pressurizer 117 is stopped to enable starting air supply, and the control device 121 releases the solenoid valve 114.
An opening command is issued, starting air is supplied to the gas bearings 107a and 107b, and the rotor 102 is supported with gas.

Incidentally, the gas bearing 107a rotatably supports the rotating shaft 101 with a certain gap, and the gas bearing 107b is a means for separating the shaft end of the rotating shaft 101 from the bracket with a certain gap.

Next, if the set pressure P of the pressure switch 115 installed in the piping immediately before the gas bearings 107a, 107b and the gas pressure P2 in the piping are P2<Pb, the turbomachine cannot be started, so the solenoid valve 114 is closed and the turbomachine is started. Return to normal condition and restart.

When P≧Pb, it is the beginning of a turbo machine! When Fjl preparation is complete, a start command is issued from the control device 121 to the inverter 120, power is supplied from the inverter 120 to the motor 103, and when the rotor 102 starts rotating, the impeller 10
4 rotates, gas is pressurized within the casing from the intake port of the turbomachine 100 and reaches the discharge side 105.

This discharged gas passes through a filter 109 and is piped to the load, but from the middle of the pipe to the tank 108, a check valve 110
The pressurized gas is branched off and supplied to the turbomachine during operation.

As the rotation speed of the impeller 104 increases, the discharge pressure also increases.

At this stage, completion of the start is determined by the time-up of the start timer 125, a pressure gauge (not shown) provided on the load piping, a tachometer provided on the motor shaft, etc., and the start stage is completed.

The discharge pressure at this stage is higher than Pa, gas is constantly replenished into the tank 108, and further gas is supplied from the tank 108 to the mist separator 113. Solenoid valve 114, gas bearing 107a
, 107b, and the normal backup pressurizer 11
7, the state of P2≧P is maintained without operation.

When starting is completed, the impuffer energizes the motor according to the speed command and rotates the rotor 102 in response to the load. Although the discharge pressure varies depending on the air layer used by the load, the capacity of the tank 108 does not increase due to surges. Since the capacity is sufficient to absorb

During the steady operation stage, the backup pressurizer 117 is operated intermittently as necessary to maintain the state of P1≧Pa, but normally the state of P1≧P can be maintained only by the gas pressure on the discharge side. Backup pressurization 11117 is rarely operated.

In addition, the discharge pressure may rise abnormally due to clogging of load piping, etc.
If Pl rises abnormally, the pressure is released by an unloader (not shown) provided in the tank 108 or the piping.

The biggest problem at this stage is a power outage, and when a power outage is detected, the emergency power is switched to 11i127, and the solenoid valve 114
Hold open and shift to emergency stop.

Stop command 123 or power outage detection 1 to control device 121 from outside
24 is input, the control device 121 outputs the power from the emergency power supply 124 in the case of a power outage, or from the inverter 1 in the case of a power outage.
20, power is supplied to the dynamic brake unit 126, a DC braking current is supplied to the stator coil of the motor 103, and the rotor 102 is electromagnetically braked. During this time, air is supplied to the gas bearings 107a and 107b from the tank 108 via the solenoid valve 114.

When the stoppage of the rotor 102 is confirmed by the timer 1° 25 or a signal from a tachometer (not shown) attached to the motor shaft, a closing command is issued from the control device 121 to the solenoid valve 114, and the stop stage is ended. .

The air supply method for the gas bearing described above is shown in the flowchart of FIG. That is, steps 201 to 210 represent a starting stage, steps 211 to 217 are operating stages of the turbomachine 100, and steps 218 to 221 are its stopping stage.

For the purpose of explanation, the explanation was given using a motor-driven turbomachine, but in the case of a turbocharger, impellers 104 are installed at both shaft ends, and the motor 103 is equipped with dynamic brake coils, etc. Ii & Den! It is easy to infer that the same operation can be achieved by providing a brake ats such as a brake or an electromagnetic brake, so the explanation will be omitted.

〔Effect of the invention〕

Thus, according to the present invention, it is possible to stably support the gas bearing from the discharge pressure during operation while absorbing surges with a small tank capacity that stores a small amount of gas sufficient to support the rotating shaft at startup or stop. At the same time, since the bearing can be stopped in a short time, excluding coasting during stopping, it is possible to provide a compact and highly reliable gas bearing that can prevent burnout due to high-speed bearing contact.

Therefore, the present invention significantly contributes to this field.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view of a part of an embodiment of the present invention and a block diagram showing the circuit configuration thereof, and FIG. 2 is a flowchart showing a control method. 100 is a turbo machine, and 101 is a rotating shaft. 107a and 107b are gas bearings, and 108 is a tank. 110.112 is a check valve, 114 is a solenoid valve. 115, 116 is a pressure switch, 117 is a backup pressurizer, 119 is an operation/control panel, 120 is an inverter device, 121 is a control head, 125 is a start timer, 127
126 is an emergency power supply, and 126 is a dynamic brake unit. Applicant's agent Mr. Sato Figure 1 Figure 2 (0)

Claims (1)

[Scope of Claims] 1. In a gas bearing that branches part of the discharge pressure of a turbomachine and supplies it to the gas bearing, there is a backup pressurizer that operates primarily to store gas in a tank during startup via a check valve. , a pipe that connects to the tank branched from the discharge pipe of the turbomachine via a check valve, and a supply pipe from the tank to the gas bearing via a solenoid valve that receives a start command and remains open until the stop is completed. A pressure switch installed in the tank, a pressure switch installed in the supply piping to the bearing immediately before the bearing, a braking means for the rotating shaft, and a pressure switch that corresponds to the start command, stop command, and set pressure of the pressure switch. An air supply device for a gas bearing, comprising: a control device for starting and stopping the backup pressurizer and operating a braking means; 2. In a gas bearing in which a part of the discharge pressure of the turbomachine is branched and supplied via a tank, and the rotating shaft is supported by the gas bearing, the residual pressure in the tank is higher than the first set pressure. Supply gas from the backup pressurizer, and when the residual pressure in the tank becomes higher than the first set pressure, open the solenoid valve and check that the piping pressure from the tank to the gas bearing just before the gas bearing is higher than the second set pressure. During the startup stage, the turbomachine is started while the solenoid valve is held open, and the pressure supplied from the discharge side of the turbomachine to the tank is increased from the backup pressurizer so that the residual pressure in the tank is higher than the set pressure. an operating stage in which the power supply is supplied or switched to emergency power in response to a power outage detection signal; and a stopping stage in which a braking means is activated in response to a power outage signal or a stop command, and a solenoid valve is closed after confirming that the power has stopped. Air supply method for gas bearings.