JPS59165801A - Adjustment method of thrust of turbo machinery and apparatus thereof - Google Patents

Abstract

PURPOSE:To suppress the face pressure of a thrust bearing within the allowable limit by turning the thrust of a turbo machinery to other parts when said thrust exceeds the allowable limit of the face pressure of the thrust bearings, thus permitting automatic adjustment of the balance of the thrust. CONSTITUTION:A balance pipe 7 is arranged to communicate the inside part of a low-pressure side bearing 5 and the part between a high-pressure side bearing 4 and a dummy ring 6, and a valve 13 installed midway in the balance pipe 7 is opened and closed by the signal supplied from a trubine watching instrument. When the indication value on the turbine watching instrument exceeds the allowable limit for the face pressure of a thrust bearing, the opening degree of the valve 13 increases, and an excessive steam thrust is supplied into the inside part of the low-pressure side bearing 5 through the balance pipe 7. Thus, the face pressure of the thrust bearing can be adjusted automatically within the allowable limit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in thrust adjustment methods and devices for turbomachines such as steam turbines, gas turbines, blowers, and compressors.

Once the steam thrust is completed, it cannot be easily changed, and there are limits to the accuracy of calculations with current technology, resulting in discrepancies between calculations and actual operation, and sometimes excessive thrust is generated. The shaft position of the turbine rotor changes significantly and an alarm occurs, and the temperature of the thrust bearing metal rises and a sear alarm occurs, which not only causes operational problems, but also wear of the thrust bearing metal, or worst case scenario. In such cases, metal burnout accidents may occur.

In such cases, adjustment has traditionally been made by inserting an orifice in the thrust balance pipe (see diagram) or installing a valve, but adjustment requires stopping the turbine or
It was a hassle because I had to manually adjust it while looking at the gauges.

The present invention was completed based on the experience of actually facing these two problems and having difficulty solving them.The present invention was developed based on the experience of actually facing these two problems and having difficulty solving them. The object of the present invention is to provide an adjustment method and device.

In order to achieve this objective, one of the methods of the present invention is to adjust the thrust of heavy machinery. The thrust bearing is characterized in that the thrust balance is automatically adjusted by relieving force to others during operation, so that the surface pressure of the thrust bearing always remains within an allowable value no matter what the operating condition changes.

In addition, in order to achieve the above object, the turbomachine thrust adjustment device of the present invention connects the vicinity of the high-pressure side bearing and the vicinity of the low-pressure side bearing in the casing that pivotally supports the turbine rotor with a balance piping. In addition, a turbine monitoring instrument equipped with a shaft position gauge or a thrust bearing metal temperature gauge is installed in a turbomachine equipped with a thrust adjustment device such as a valve or orifice in the middle of the balance piping, and the shaft position gauge or It is characterized in that the thrust force adjustment device is controlled by a signal taken out by a thrust bearing metal thermometer.

Hereinafter, details of the present invention will be sequentially explained according to embodiments illustrating the details.
do.

Figure 1 shows an example of a turbomachine that is categorized as an impulse type turbine based on its operating method and as a backpressure turbine based on the status of steam entering and exiting the turbine.
The turbine rotor 2 that is pivotally supported within the turbine rotor 2 is provided with a plurality of stages in parallel, each consisting of a set of a disk 21 formed integrally with the turbine rotor 2 and a rotor blade 3 embedded in the disk 21. . 4 is a high-pressure side bearing (also called a high-pressure gland ring) of the casing 1; 22 is a shaft protrusion of the turbine rotor 2 that comes into contact with the high-pressure side bearing 4; and 5 is a low-pressure side bearing (also called a low-pressure grand ring) of the casing 1. 5L23 is a shaft protrusion portion of the turbine rotor 2 that comes into contact with the low pressure side bearing 5;
6. is a dummy ring provided in the inner casing portion of the high-pressure side bearing 4, and its diameter is larger than that of the high-pressure side bearing 4. Reference numeral 24 denotes a shaft protrusion of the turbine rotor 2 that comes into contact with the dummy ring 6, and has a larger diameter and protrudes higher toward the outer periphery than the shaft protrusion 22.

A portion of the casing l between the high-pressure side bearing 4 and the dummy ring 6 and an inner portion of the low-pressure side bearing 5 are provided with a second
As shown in the figure, a balance pipe 7 is arranged and installed to connect these parts, and the balance pipe 7 is used to collect leakage steam from the outlet of the dummy ring 6 (in the case of an extraction turbine). In the case of a water turbine, the oil is recovered to an appropriate location in the low pressure stage.

In the case of a condensing turbine, the dummy ring 6 is divided into a plurality of parts, and the intermediate outlet is connected to an appropriate location in the middle stage of the turbine (usually a bleed stage for a feedwater heater).

Therefore, during operation of the turbine, the steam thrust 8 that acts on the rotor blades 3 and the disk 21 can be generated by appropriately determining the inner diameter of the dummy ring 6, so that the turbine rotor protrusion provided correspondingly inside the dummy ring 6 can be 24 (so as to be able to balance the steam thrust 9 in the opposite direction).

Note that since the inner diameters of the high-pressure gland ring 4 and the low-pressure gland ring 5 are usually made equal, the steam thrust 10.11 acting on the rotor shaft protrusion 22.23 corresponding to both is approximately small and approximately balanced. It has become.

In this manner, when designing a turbine, the inner diameter of the dummy ring 6 is determined so that the steam thrust is either zero or sufficient to be received by the thrust bearing.

However, in an actual turbine, during operation, the nozzle 12
The steam pressure distribution generated around the rotor blades 3 may deviate from the planned value due to impurities contained in the steam adhering to the rotor blades 3 in the form of scale, or manufacturing errors in the nozzle 12 or the rotor blades 3. Sometimes. Furthermore, calculations and actual steam pressure differences that occur before and after the disk 21 often do not match, and as a result, sometimes an excessive or large steam thrust is generated.
This has led to accidents such as thrust bearing wear and burnout.

Therefore, a valve 13 is provided in the middle of the balance pipe 7,
The opening and closing of the valve 13 can be adjusted by stopping the turbine,
Alternatively, it has been conventionally known to manually adjust while looking at a meter.

The present invention automatically opens and closes the valve 13 during operation without stopping the turbine. It can be opened and closed by manual operation, etc., and the control signal 1
4 is configured to be taken out using a shaft position meter of the turbine rotor 2 or a thrust bearing metal thermometer (not shown).

One possible method for opening and closing the valve 13 is to operate a link mechanism (not shown) on the outer periphery of the casing 1 using a hydraulic actuator. These shaft position gauges or thrust bearing metal temperature gauges are included in turbine monitoring instruments (not shown).

Next, the operation of the thrust adjusting device configured as described above will be explained.

First, when operating the thrust adjustment device.

Please make the following preparations (i.e., steam thrust 9.1O111 is calculated and actually matches well (but thrust 8 is.

As mentioned above, calculations may not match reality, and even if they match at the start of operation, they may gradually deviate from each other. This deviation may be large or small, so if the deviation is large, then in order to balance it,
Since it is necessary to reduce the outlet pressure of the dummy ring 6, it is necessary to prepare the valve 13 in advance so that the valve 13 can be opened.
Plan so that the thrust is balanced with 3 reduced.

The deviation of this thrust from the planned value results in a change in the surface pressure of the thrust bearing, which is detected as a change in the indication of the shaft position meter of the turbine monitoring instrument and a rise in the temperature of the thrust bearing and metal thermometer. Therefore, allowable ranges are determined in advance for these indicated values.

When the surface pressure of the thrust bearing exceeds the allowable range of the indicated value, the monitoring instrument detects a change in the indication of the shaft position meter or a rise in the temperature of the bearing metal thermometer, and issues a signal. , the valve 13 increases its opening degree by hydraulic or electrical operation, and in order to lower the outlet pressure of the dummy ring 6, excessive steam thrust flows through the balance pipe 7 and is fed to the inner part of the low-pressure side bearing 5. .

In this way, by changing the pressure at the outlet of the dummy ring 6, the thrust force 9 (the thrust force 10 also changes, but because the relevant turbine rotor diameter is small, it is smaller than the thrust force 9) is changed, and the total thrust is Make sure that it does not become excessive. When the valve 13 is fully open, the outlet pressure of the dummy ring 6 is the lowest.
As the valve 13 is closed, its outlet pressure +-i gradually increases. Therefore, the pressure difference between the inlet and outlet of the dummy ring 6 decreases, and the steam thrust 9 decreases. On the other hand, the thrust 10 increases, but since the inner diameter of the dummy ring 6 is larger than the inner diameter of the high-pressure gland ring 4, the steam thrust decreases as a whole, and it moves toward the right in FIG. The thrust from the high pressure side to the low pressure side will increase.

As described above, according to the present invention, a permissible range is determined in advance for the specified value of the shaft position meter of the turbine monitoring instrument and the thrust bearing metal thermometer, and when the surface pressure of the thrust bearing exceeds the permissible range. , it is possible to generate a signal from one of these monitoring instruments to open or close the valve of the balance pipe, thereby automatically adjusting the surface pressure of the thrust bearing and its thrust so that it falls within the permissible range. .

Therefore, according to the present invention, when the planned (calculated) thrust differs from the actual thrust and excessive thrust is generated, or when excessive thrust is generated due to changes during operation, the turbine can be modified. It is possible to continue operating safely without taking such measures.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a turbomachine embodying the present invention;
The figure is an explanatory diagram of the operation of the main parts of the turbomachine. DESCRIPTION OF SYMBOLS 1--Casing, 2...Turbine rotor, 4...High-pressure side bearing, 5...Low-pressure side bearing, 6...Dummy ring, 7...Balance pipe, 13--W, 14-Redirection signal.

Claims (2)

[Claims] (1) When the thrust generated by the working medium of the turbomachine exceeds the permissible limit of the surface pressure of the thrust bearing, the thrust in excess of the permissible limit is released to other sources during operation to automatically balance the thrust. A thrust adjustment method for a turbomachine, characterized in that the thrust bearing is adjusted so that the surface pressure of a thrust bearing always falls within an allowable value no matter what the operating conditions change. (2) Connect the vicinity of the high-pressure side axis and the vicinity of the low-pressure side bearing in the casing that pivotally supports the turbine rotor with a balance piping, and install a thrust adjustment device such as a valve or orifice in the middle of the balance piping. In turbomachinery,
A turbo equipped with a turbine monitor equipped with a shaft position gauge or a thrust bearing metal thermometer, and configured to control the thrust adjustment device by a signal taken out from the shaft position gauge or thrust bearing metal thermometer. Machine thrust adjustment device.