JP2955950B2 - Abnormality detection method for gas bearing type expansion turbine and start-up method of air separation device using the same - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in a gas-bearing expansion turbine and a method for starting an air separation device using the same. And a method for easily detecting the presence or absence of an abnormality in the expansion turbine before starting the air separation device and confirming that there is no abnormality before starting the air separation device.

[Prior Art] Conventionally, after completion of the assembly of a gas-bearing type expansion turbine mainly used for an air liquefaction / separation device, the presence or absence of an abnormality in a bearing before starting the device is confirmed by a method as shown in FIG. I was That is, one lead wire 1a of the tester 1
Is brought into contact with the outer surface of the casing 3 of the gas bearing type expansion turbine 2, and the other lead wire 1 b is connected to the vinyl-coated conductor 4, and the tip of the vinyl-coated conductor 4 is provided through the casing 3. Attachment 5
The bearing gas G is supplied to rotate the expansion turbine 2 in a state in which the casing 3 is in contact with the tip of the turbine wheel 6 (the tip of the turbine shaft 7). It was confirmed that the turbine shaft 7 and the bearing 8 were not in contact with each other based on the presence or absence of conduction between them.

[Problems to be solved by the invention]

However, in the above-described method, it was not possible to externally check whether the tip of the vinyl-coated conductor 4 is in contact with the tip of the turbine wheel 6, and there was a possibility of erroneous confirmation due to a contact error. In addition, there is also a problem that foreign matter may enter the expansion turbine 2 due to the insertion and removal of the vinyl-coated conductor 4, and if the foreign matter that has entered the bearing portion is an insulator, it cannot be detected. .

On the other hand, in recent air separation apparatuses, their shutdown and restart have been performed more frequently than before due to remote automatic operation of the apparatus. However, the above-described conventional method for detecting an abnormality of an expansion turbine is performed mainly for the inspection immediately before assembling and operating the device. Therefore, it is difficult to perform the inspection using the above method when the air separation device is restarted. In addition, since it is difficult to incorporate the device into a device, inspection of a device operated by remote automatic operation is hardly performed.

Therefore, the present invention can easily detect an abnormality of the gas-bearing type expansion turbine even at a remote location before starting the air separation device, and inspect the presence or absence of abnormality of the expansion turbine in advance to confirm that there is no abnormality. It is an object of the present invention to provide a method by which the device can be activated afterwards.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides an optical sensor with an optical sensor at the front of a blade of a turbine wheel of a gas-bearing expansion turbine, or at the front of a blade of an impeller of a compressor directly connected to the expansion turbine. Before starting the air separation device, a sensor head is provided, and only the bearing gas is supplied to the gas-bearing type expansion turbine to rotate the expansion turbine at a constant low speed. An abnormality detection method for a gas-bearing type expansion turbine characterized by detecting a pulse and detecting irregularities of the pulse, and a gas-bearing type expansion turbine and an automatic control system for remote automatic operation Before starting the air liquefaction / separation apparatus, before starting the air liquefaction / separation apparatus, only the bearing gas is supplied to the gas-bearing type expansion turbine and the gas By rotating the expansion turbine at a constant low speed, the passage interval of the blades of the turbine wheel of the expansion turbine or the impeller of the compressor directly connected to the expansion turbine is measured, and the irregular rotation of the rotation of the expansion turbine is measured. The present invention provides a method for starting the air separation device, wherein the start of the air separation device is started after detecting the performance and confirming that there is no abnormality in the expansion turbine by remote automatic operation.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to FIGS. 1 to 3 based on one embodiment in which a gas bearing expansion turbine is provided in an air separation device. The configuration of the air separation device can be applied to any type of a known air separation device having a gas-bearing type expansion turbine, and the configuration of the air separation device does not have a feature. ,
The illustration and description thereof are omitted.

First, FIG. 1 shows a main part of a gas bearing type expansion turbine (hereinafter simply referred to as an expansion turbine) 11. The configuration of the expansion turbine 11 itself is the same as the conventional one,
Holds the turbine shaft 14 so that it can rotate at high speed in a non-contact state by the bearing gas G supplied to the bearing 13. At the tip of the turbine shaft 14, a turbine wheel 15 is fixedly mounted. The turbine wheel 15 is rotated by the pressure of a high-pressure gas introduced from an intake port (not shown) to adiabatically expand the high-pressure gas to generate cold. To the discharge port (16).

In the air separation device, a compressor (brake blower) (not shown) is usually provided integrally with the expansion turbine 11, and an impeller of the compressor is fixed to the other end of the turbine shaft 14. Gas is being pressurized.

In order to carry out the method of the present invention, as shown in FIG. 2, the sensor head 18a of the optical sensor 18 which has passed through the casing 17 in an airtight manner is attached to the front of the blade 15a of the turbine wheel 15 of the expansion turbine 11. They are provided at appropriate intervals.
The optical sensor 18 outputs, as a pulse signal, a passage interval of the blade 15a crossing the front surface of the sensor head 18a as the turbine wheel 15 rotates, and outputs the pulse signal from the light emitting unit of the pickup 18b (light emitting unit and light receiving unit). The received pulse signal is received by the light receiving section, and the pulse is measured by the pulse interval measuring device 19 to detect the regularity and irregularity of the rotation of the turbine wheel 15, thereby detecting the bearing section 12 of the expansion turbine 11. It is configured to detect abnormality.

Before starting the air separation device, when bearing gas G is supplied to the bearing portion 12 at a predetermined pressure in a no-load state, that is, without supplying gas to the turbine wheel 15 portion of the expansion turbine 11, the turbine shaft The rotor 14 floats from the bearing 13 by the pressure of the bearing gas G and starts to rotate, and has a constant rotation speed corresponding to the pressure of the bearing gas G, usually 20 to 30 rotations per minute. In this way, when the turbine shaft 14, that is, the turbine wheel 15 is rotating at a constant low speed, when the optical sensor 18 detects the passage interval of the blade 15a, if the arrangement interval of the blade 15a is equal, , Pulse signals at regular intervals are obtained. Normally, the blades 15a of the turbine wheel 15 are provided at regular intervals, so that the obtained pulse signals have regular intervals in accordance with the pressure of the bearing gas G supplied.
At this time, when foreign matter such as water or dust enters the bearing portion 12, the foreign matter pushes the turbine shaft 14 to be eccentric, and the bearing 12 is eccentric.
As a result, the pulse signal is disturbed due to the rotation irregularity caused by contact with the pulse signal 13.

Therefore, as shown in FIG. 3, the pulse interval measurement device 19 is set to a predetermined value B of the number of pulse intervals within a certain range with respect to the normal pulse width A corresponding to the pressure of the gas supplied from the bearing gas G. When the pulse signal exceeds the specified value B by setting the permissible width of the disturbance (point C)
Further, it is possible to know that an abnormality has occurred in the bearing portion 12, for example, that a foreign matter has entered the bearing portion 12.

Then, if no abnormality is detected, the expansion turbine 11 enters the load operation. On the other hand, an alarm for notifying the occurrence of an abnormality to the rotation measuring device 19 and an output circuit 19 for stopping the operation of the device are provided.
If “a” is provided, the operator can be notified of the abnormality of the expansion turbine 11. This makes it possible to prevent useless start-up operation of the device and failure of the expansion turbine 11, thereby preventing an accident caused by an abnormality of the expansion turbine 11 and improving safety.

As described above, by detecting the passage interval of the blade 15a of the turbine wheel 15 with the optical sensor 18, it is possible to detect even slight rotation unevenness that cannot be detected by a normal tachometer that simply measures the number of rotations. And under an extremely slow rotation speed,
An abnormality can be detected before a failure occurs, and an abnormality due to invasion of a minute foreign matter that becomes a problem during ultrahigh-speed rotation can be detected.

That is, in a normal turbine tachometer, 1 to 1
With two pulses, it is difficult to detect a difference in pulse interval within one rotation, and it is difficult to detect an abnormality in advance if the number of rotations is large or small.

In addition, by detecting the rotation unevenness of the turbine wheel 15 using the optical sensor 18 and detecting the abnormality of the bearing portion 12, the presence or absence of the abnormality of the bearing portion 12 in a non-contact state with the turbine wheel 15 or the turbine shaft 14. Can be detected, so that no burden is imposed on each part of the expansion turbine 11, and erroneous confirmation due to a contact error unlike the conventional contact method does not occur. The expansion turbine 11
Since it is possible to prevent the foreign matter from entering the portion, it is possible to detect the presence or absence of an abnormality when necessary.

In particular, in an air separation device equipped with an automatic control system for remote automatic operation, the device is stopped and restarted more frequently than before, but according to the method of the present invention, before the restart, the expansion turbine It is possible to confirm the presence or absence of the abnormality in 11, and as described above, it is possible to prevent useless operation and failure of the device beforehand, and to improve safety.

In the above-described embodiment, the example in which the sensor head of the optical sensor is disposed in the turbine wheel portion of the expansion turbine has been described. However, when the expansion turbine is integrally provided with the compressor, Even if the sensor head is provided in front of the impeller blades of the directly connected compressor, the same operation and effect as described above can be obtained. Normally, the expansion turbine is arranged on the cryogenic side and the compressor is arranged on the room temperature side.Therefore, providing an optical sensor in the impeller of the compressor makes the device of the sensor cable and the like easier, and reduces cost and cost. It is preferable from the viewpoint of maintenance.

In this embodiment, the expansion turbine is provided in the air liquefaction / separation apparatus. However, the present invention can be similarly applied to other apparatuses such as a gas liquefier and a refrigerator.

Next, a starting method of the air liquefaction / separation apparatus to which the abnormality detection method of the gas bearing type expansion turbine of the present invention is applied will be described.

The configuration of the air liquefaction / separation device is a device equipped with a gas-bearing type expansion turbine as described above, and an air liquefaction / separation device equipped with an automatic control system for remote automatic operation.
Any type of device can be applied. In this embodiment, the above-described abnormality detection method is incorporated as one step of a start-up method by automatic operation using an automatic control system for automatic operation of the device.

Hereinafter, this process will be described based on the automatic start control flow diagram shown in FIG.

First, in “Use expansion turbine?” In step S1, as a pre-startup preparation, the operator selects the use of the expansion turbine using the mode selection switch on the field control system panel, and confirms the opening of the bearing gas main valve. If the selection not to use the expansion turbine is made, the process jumps to step S3.

When the use of the expansion turbine is selected in step S1,
The panel display indicates "use of expansion turbine = Y", and then the process proceeds to step S2, where "is there an abnormality in expansion turbine?" Is displayed. Here, the inspection process based on the above-described abnormality detection method is automatically performed, and if an abnormality is detected in the expansion turbine, the process branches to step S4, where an abnormality is displayed (a lamp, a buzzer, etc.), and a start switch is displayed. The device will not be started even if is inserted.

If no abnormality is detected in the expansion turbine in step S2, the process proceeds to step S3, "Is startup preparation completed?" Here, the operator checks the state of the preparation work of each part of the air liquefaction separation device, proceeds to the step of `` start switch on '' in step S5, the start switch is turned on,
The automatic start-up operation of the apparatus is performed according to a process usually performed as a start-up method of each type of air liquefaction separation.

By performing the automatic start-up operation in such a process, the automatic start-up operation by the remote control becomes possible. In particular, the frequent stop and restart operations, which are often required in recent devices, can be continued by remote control with confidence. Now you can get it.

〔The invention's effect〕

As described above, according to the present invention, it is possible to detect the presence or absence of an abnormality in a non-contact state with a turbine wheel or an impeller or a turbine shaft. Such an erroneous confirmation due to a contact error does not occur, and the presence or absence of an abnormality can be reliably detected. Further, since it can be permanently installed in the expansion turbine, it is possible to prevent intrusion of foreign matter from the portion and to detect the presence or absence of an abnormality when necessary.

In particular, in an air separation device equipped with an automatic control system for remote automatic operation, before restarting, it is possible to confirm the presence or absence of an abnormality in the expansion turbine each time. Stopping and restarting are possible, so that useless operation and failure of the device can be prevented beforehand, and safety can be improved.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a sectional view of a main part of an expansion turbine, FIG. 2 is a front view of a turbine wheel, and FIG. Explanatory drawing of state, 4th
The figure shows an example of the automatic start control flow diagram,
FIG. 5 is a sectional view showing an example of a conventional abnormality detection method. 11 ... Expansion turbine, 12 ... Bearing part, 13 ... Bearing, 14 ...
… Turbine shaft, 15 …… turbine wheel, 15a …… wing, 18…
… Light sensor, 18a …… Sensor head

Claims (2)

(57) [Claims] 1. A sensor head of an optical sensor is provided at a front part of a blade of a turbine wheel of a gas bearing type expansion turbine or at a front part of a blade of an impeller of a compressor directly connected to the expansion turbine. Before starting the apparatus, only the bearing gas is supplied to the gas-bearing type expansion turbine to rotate the expansion turbine at a constant low speed, and the optical sensor detects the number of passages of the blade as a pulse signal, and the pulse signal A method for detecting an abnormality of a gas-bearing type expansion turbine characterized by detecting irregularity of the gas turbine. 2. When starting an air liquefaction / separation apparatus equipped with a gas-bearing type expansion turbine and equipped with an automatic control system for remote automatic operation, the gas-bearing / type expansion turbine is started before starting the air liquefaction / separation apparatus. Only the bearing gas is supplied to the turbine to rotate the gas-bearing type expansion turbine at a constant low speed and pass through the blades of the turbine wheel of the expansion turbine or the blades of the impeller of the compressor directly connected to the expansion turbine. Measuring the intervals, detecting irregularities in the rotation of the expansion turbine, confirming that there is no abnormality in the expansion turbine by remote automatic operation, and then starting the operation of the air separation device; How to start the device.