JPS59201903A - Automatic starter of oil tank ventilator - Google Patents

Abstract

PURPOSE:To improve operation reliability, by a method wherein, in a device which prevents leakage of oil by maintaining the inside of an oil tank in a negative pressure state, a preliminary air ejector is automatically started to produce a negative pressure when an exhaust fan, serving to produce the negative pressure of the device, is brought to a stop. CONSTITUTION:When the function of an exhaust fan 17 is brought to a stop due to a power source trouble or failure in operation of a motor 16 or the exhaust fan 17, a check valve 23, located on the discharge side of the exhaust fan 17, is closed occasioned by reduction in a wind pressure. When an opening detector 30 detects such closing of the check valve, in response to a detecting signal therefrom, an automatic on-off valve 31 is opened through a transducer 36, and a pressure air is fed to a nozzle 34 of an air ejector 18 through an air feed pipe 25 and is injected therethrough. This brings the interior of a suction chamber 35 of the air ejector 18 into a negative pressure, and causes the air in an oil tank 1 to be sucked out through a piping 24. The air is exhausted through a check valve 27, forcibly opened thereupon, and a piping 28 to a piping 22, and the interior of the oil tank 1 is maintained in a negative pressure state.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a lubricating oil system for a steam turbine.

[Background of the invention]

FIG. 1 shows a typical example of a conventional steam turbine lubricating oil system. Lubricating oil 2 in an oil tank of 1 yen is sucked from a strainer 5 by an oil pump 4 driven by an electric motor 3, and then passed through an oil pipe 6.
The bearings 11a, llb, IIC of the steam turbine
, lid, and serves as lubricating oil for each bearing. The lubricating oil that worked on each bearing is the bearing 11a, l'lb.

11C, bearing boxes 12a and 12b containing lids.

The oil flows into the reservoir 12CPF3, flows through the oil drain pipes 13a, 13b, and 13c, passes through the oil drain pipe 10, and is collected in the oil tank 1. (
(The dotted line in the figure indicates the returned oil).

The rotor 14 of the steam turbine 9 and each bearing box 12a.

Seal parts 12b and 12C, 15a and 15b.

Oil may leak from 15C, 15d, 15e, and 15f. In order to prevent this, negative pressure is created in the oil drain pipes 10+13a+13b, 13C including the oil tank 1 and the bearing boxes 12a, 12b, 12C, and the seals 15a...15f are removed. Generally, it is sucked into the oil tank 1 to prevent leakage.

This device is an exhaust fan 17 driven by an electric motor 16 installed on the top surface of the oil tank 1.

Furthermore, the air ejector 18 is provided as a bank amplifier when the exhaust fan fails.

The system related to the exhaust fan 17 driven by the electric motor 16 has a flow rate adjustment valve 32 in the middle of the suction pipe 29 and is connected to the oil tank 1, and the suction force of the exhaust fan 17 causes the oil tank to have negative pressure. Adjust the degree of negative pressure between the gas and the gas. on the other hand,
The exhaust side of the exhaust fan 17 passes through the plumber 9 and the expansion joint 2o, and a check valve 23 is provided between the piping 21 and the piping 22, and is discharged to the atmosphere opening pent 33.

The air ejector 18 is connected to the oil tank 1 and the piping 24, and the air supply tube 25 from the driving air source is supplied to the air ejector 18 through the main valve 26 and discharged from the nozzle 34. The exhaust air from the air ejector 18 is connected to the pipe 22 via a check valve 27. Normally, an electric motor-driven exhaust fan 17 is operated to suck air from the oil tank and create a negative pressure inside. In this case, since the air ejector 18 is normally stopped, the air supply source valve 26 is closed.

The relationship between the check valve 23 and the check valve 27 is that when the exhaust fan 17 is operating, the check valve 23 opens due to the exhaust pressure, while the check valve 23 for the air ejector 18 on the stop side opens due to the exhaust pressure. Closed by pressure.

When the function of the exhaust fan 17 stops due to a failure of the exhaust fan 17 and the electric motor 16, or a failure of the power supply side, etc.
An air ejector 18 is prepared to operate as a substitute, but to operate it, the air supply source valve 26 is manually operated by the operator, and the interior of the oil tank is closed for a period of time until the air ejector 18 is operated. Negative pressure is not ensured, and positive pressure is created due to vaporization of lubricating oil, etc., and the pressure increases. During this time, the pressure inside the bearing boxes 12a, 12b, 12C of the steam bin 9 increases,
The lubricating oil (oil paper) is blown onto the rotor 14 and each seal portion 15 al 15 br 15 cr 15d,
15e and 15f had the drawback of leaking to the outside.

[Embodiments of the invention]

2, 3 and 4 show embodiments of the invention.

In FIG. 2, a check valve 23 attached to the discharge side of the exhaust fan 17 is opened by the wind pressure caused by the amount of exhaust air, so that the air extracted from the oil tank 1 by the operation of the exhaust fan 17 is opened. An opening detector 30 that detects the opening of this check valve 23 transmits an opening/closing signal to a converter 3G, which converts this signal, and responds to this by transmitting an opening/closing signal to a converter 3G. The signal is transmitted to the automatic on-off valve 31, which opens and closes this valve.

The automatic on-off valve 31 shown in FIG. 2 is an electric valve driven by an electric motor, but as shown in FIG. 3, an air-operated valve 41 is used.
An opening/closing signal from the converter 36 is guided through an electromagnetic valve 42 from an air pipe 43 branched from the air supply tube 25 to an air-operated valve 41 to open and close this valve. Further, in FIG. 2, the automatic on-off valve 31 may be an electromagnetic valve type on-off valve.

The operation will be explained with reference to FIG. If the function of the exhaust fan 17 is stopped due to a failure of either the electric motor 16 or the exhaust fan 17 due to a power supply failure or equipment failure, the check valve 23 provided on the discharge side of the exhaust fan 17 will stop the exhaust fan 17 from functioning. 17, the exhaust air pressure decreases, and at the same time, the check valve 23 changes from an open state to a closed state. Due to this closing, the opening detector 30 converts the closing signal to the converter 36.
, the converter 36 automatically opens and closes the valve 31, and
Immediately, the pressurized air from the air supply pipe 25 is guided to the nozzle 34 of the air ejector 18, which discharges the pressurized air. As a result of this discharge, the suction chamber 35 of the air ejector 18 becomes a negative pressure, and air is sucked in from the oil tank 1 through the piping 24 connected thereto and discharged from the air ejector 18.

This extracted air has some pressure, pushes open the check valve 27, passes through the pipe 28, and joins the pipe 22. This extracted air pressure closes the check valve 23 more strongly to prevent backflow to the exhaust fan 17 side.

Through this series of operations, when the exhaust 7-an 17 is stopped, it is immediately and smoothly switched to the air ejector 18.

FIG. 4 describes an example in which the exhaust 77 unit driven by an electric motor is installed as a standby unit, which is the same as the normally operating unit. The components of the electric motor 16a-, exhaust fan 17a1, and other accessories have the same functions as normally operating equipment, and if the electric motor 16 or the exhaust fan 17 stops functioning due to a power failure or failure, there will be no reverse check. The valve 23 closes, and the closed signal from the opening detector 30 linked to this is transmitted to the converter 36a, and this signal operates the electromagnetic switch 47, which starts the spare electric motor 16aK and exhaust fan 17a. .

Due to this startup, the air from the oil tank 1 is transferred to the flow rate adjustment valve 3.
2a and piping 29a, and is discharged from the exhaust fan 17a. This exhaled air passes through the pipe 19a1, the expansion joint 20-a, and the pipe 21a, opens the check valve 45, and passes from the pipe 46 to the pipe 2.
Join 2. A signal from an opening detector 49 that detects the opening of the check valve 45 is transmitted to the converter 36a, and a mode is set to return the motor 16 to the next starting condition. This method detects the opening of the check valve and starts the exhaust fan on the standby side. Unlike conventional technology, which detects the power supply, this method detects the opening of the check valve and detects the final discharge status of the exhaust fan. Since the valve is detected only once, safety can be increased.

The purpose of this invention is to extract the air in the oil tank and create a negative pressure, but this negative pressure must be less than 130 meters of water column, and since the negative pressure is a small value when detected with a pressure detector, However, from the standpoint of reliability, a reliable method is to detect the opening of a check valve that is always opened depending on the air extracted from the oil tank.

With this method, any condition such as power supply failure, electric motor failure, exhaust fan failure, etc. will be detected.

From the above, it is possible to prevent oil leakage from the bearing box seal of a steam turbine due to poor air extraction inside the oil tank, and in connection with this, when a hydrogen-cooled generator is connected to a turbine, oil leakage from the lubrication equipment can be prevented. Since oil is supplied to the generator bearings, a small amount of hydrogen mixed in the returned bearing oil is also continuously discharged through the exhaust gas 77. In addition, the area near the steam turbine is at a high temperature, and fires that may be caused by oil leakage can be prevented.

In addition, 48 in the figure is an electromagnetic switch.

〔Effect of the invention〕

According to the present invention, it is possible to detect the opening/closing of the check valve on the outlet side of the exhaust fan driven by the electric machine, and automatically start the air ejector as a standby unit or the standby exhaust fan based on this signal.1) When the regular electric motor-driven exhaust fan function stops, the standby fan can be automatically started immediately.

2) When switching from regular use to standby, negative pressure can be maintained in a very short time, and oil leakage from the bearing can be prevented.

[Brief Description of the Drawings] Fig. 1 is a conventional lubrication system diagram, Fig. 2 is a system diagram of an electric motor-driven exhaust fan and air ejector according to an embodiment of the present invention, and Fig. 3 is a system diagram of a motor-driven exhaust fan and air ejector according to an embodiment of the present invention.
4 are system diagrams of other embodiments of the present invention. 17...Exhaust fan, 17a...Exhaust fan, 18
30 3t

Claims (1)

[Scope of Claims] 1. In a facility comprising an electric motor-driven exhaust fan that creates a negative pressure in an oil tank, and an air ejector that banks up this exhaust fan, / a check valve on the discharge side of the exhaust fan; An automatic oil tank ventilation system characterized in that the air ejector on the standby side is configured to detect a signal from the opening of the exhaust fan and automatically start the air ejector on the standby side depending on the opening according to the discharge air volume when the exhaust fan is stopped. Ki @
Device.