JPS62138073A - Starting method for turning gear in vacuum - Google Patents

Abstract

PURPOSE:To shorten the starting time by evacuating the inside of a vacuum vessel up to a predetermined pressure, heating the outer surface of the vacuum vessel by a fluid at a high temperature and driving a revolving electric machine installed into the vacuum, vessel. CONSTITUTION:A rotary vacuum pump 7 is operated. A valve 12 is opened at the time T1 when a pressure-fluctuation gradient is made easy, and fluid at a high temperature is made to flow into a fluid path 10. The inner surface of a vacuum vessel 1 and an interior part such as a motor are degassed and treated by the heating. The valve 12 is controlled to be closed at the time T2 after a fixed time passes. The valve 12 is controlled to be opened again at the time T3 when pressure is made lower than that at the time T1. The inside of the vacuum vessel 1 is evacuated up to predetermined pressure or less, repeating the opening and closing of the valve 12. The motor 4 is driven at the time reaching target pressure. The valve 14 is controlled to be opened at the time when operation transfers to stationary operation, and a fluid at a low temperature is made to flow through the fluid path 10.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for starting a rotating device in a vacuum having a rotating electrical machine installed in a vacuum container, and particularly to a method for starting a rotating device in a vacuum, which is capable of shortening the starting time. Regarding the startup method.

[Technical background of the invention and its problems]

In some types of plants, a rotating electric machine is installed in a vacuum container and the rotating electric machine is operated in a vacuum atmosphere. FIG. 3 shows a typical example of such a vacuum rotation device, in which a motor 4 consisting of a rotor 2 and a stator 3 is installed inside a vacuum container 1. The stator coil wire end of the motor 4 is connected to an external motor drive power source (not shown) through the hermetic seal 5, and the exhaust port 6 of the vacuum container 1 is connected to the rotary vacuum pump 7. ing. In addition.

In the figure, numerals 8 and 9 indicate bearings.

By the way, when starting up the vacuum rotating device configured as described above, the following method is usually adopted. That is, first, the rotary vacuum pump 7 is operated to evacuate the inside of the vacuum container 1.

Then, when the pressure inside the vacuum container 1 drops below a certain level, the motor drive power is turned on and the motor 4 starts rotating.

However, when the above startup method is adopted, the following problems occur. Namely.

If a motor drive power source designed to increase the rotation speed of the motor 4 to the rated rotation speed with the least amount of electric power is used, a considerable amount of time is required to increase the rotation speed to the rated rotation speed. This is due to the following reasons. That is, when the inside of a vacuum container is evacuated using the most common rotary vacuum pump, only the evacuating characteristics shown in FIG. 4 can be obtained. In this figure, the horizontal axis shows the elapsed time from the time when the vacuum pump started operating, and the vertical axis shows the pressure inside the vacuum container. As can be seen from this figure, the gas is rapidly exhausted at the beginning of the exhaust, and then it is gradually exhausted, but the slope becomes very gentle. This is determined by the relationship between the volume inside the vacuum vessel and the displacement of the rotary vacuum pump, especially.

This becomes noticeable when the volume of the vacuum container is large and the displacement of the rotary vacuum pump is small. Therefore, using a motor drive power supply designed as described above.

If the motor 4 is started without sufficient evacuation, it will be balanced at a rotation speed that is lower than the rotation speed determined by the amount of supplied power by the amount of windage loss, and rotate as the pressure inside the vacuum vessel 1 gradually decreases. It takes a considerable amount of time to increase the number of revolutions to the rated number while following the process of gradually increasing the number of revolutions.

If it takes a long time to start up as described above, a loss of time will be inevitable if the inside of the vacuum container 1 is repeatedly returned to atmospheric pressure for operation.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a method for starting a rotating device in a vacuum, which can significantly improve the exhaust characteristics and shorten the start-up time. It's about doing.

[Summary of the invention]

According to the present invention, an in-vacuum rotating device is configured to evacuate the inside of the vacuum container to a predetermined pressure while heating the outer surface of the vacuum container with a high-temperature fluid, and then drive a rotating electric machine installed in the vacuum container. A startup method is provided.

〔Effect of the invention〕

According to the present invention, since the vacuum container is heated from the outside using a high-temperature fluid, the inner wall surface of the vacuum container, the motor, and other internal components of the vacuum container can be forcibly degassed. . This degassing treatment improves the exhaust characteristics and allows the exhaust to be evacuated to a certain pressure or less in a short time. As a result, it is possible to shorten the startup time.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a vacuum rotation apparatus to which the method of the present invention is applied. In this figure, the same parts as in FIG. 3 are given the same reference numerals. Therefore, a detailed explanation of the overlapping portion will be omitted.

In this example, a fluid passage 10 is provided on the outside of the vacuum container 1 so as to double as the wall of the vacuum container 1 and to surround the vacuum container 1 . The inlet 11 of the fluid passage 10 is connected via a valve 12 to a high-temperature fluid supply source 13 such as high-temperature water or high-temperature steam, and is also connected via a valve 14 to a low-temperature fluid supply source 15 .

Next, referring to FIG. 2, the startup procedure of this device will be explained. First, the rotary vacuum pump 7 is started to operate. When the rotary vacuum pump 7 starts operating in this manner, the inside of the vacuum container 1 is rapidly evacuated as shown in FIG. 2 at the beginning, and then the pressure change gradient becomes gentle. At the time point T1 when the temperature becomes gentle, the valve 12 is opened.

When the valve 12 is controlled to be "open", high temperature fluid flows into the fluid passage 1o as shown by the solid line arrow in the figure. Therefore, the wall of the vacuum container 1 is heated, and the inner surface of the vacuum container 1 and internal components such as the motor are degassed by this heating. Due to this degassing, the pressure inside the vacuum container 1 temporarily increases. The high temperature fluid is flowed for a certain period of time while the rotary vacuum pump 7 continues to exhaust the air.

At time T2, the valve 12 is controlled to be 'closed'.

This valve? By the ri+ control, degassing is stopped and the pressure inside the vacuum vessel 1 is reduced again. Then, at the time T3 when the pressure has decreased from the pressure at the second time T1, the valve 1 is again
2 is controlled to be ``open'' to allow high-temperature fluid to flow into the fluid passage 10 for a certain period of time. Thereafter, the inside of the vacuum container 1 is evacuated to a certain pressure or less while repeatedly opening and closing the valve 12. Then, the motor 4 is driven when the target pressure is reached. Further, at the time of transition to steady operation, the valve 14 is controlled to be "open" so that the low temperature fluid flows into the fluid passage 10.

With such a startup method, the time required to evacuate the inside of the vacuum container 1 to the target pressure can be shortened, and the startup time can be shortened. In other words, since the vacuum container 1 is forcibly heated to expedite degassing, the time required for degassing can be shortened compared to when degassing is done only by the suction force of the rotary vacuum pump 7. , the time required to reach the target pressure can be shortened. Therefore, it is possible to contribute to shortening the startup time.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways, such as coaxially driving the rotating body inside the container using the motor as a drive source. Alternatively, the time required to reach the target pressure may be further shortened by flowing low-temperature fluid into the fluid passage 10 when the pressure within the vacuum container has decreased to a certain value. In addition, in the above-mentioned embodiment, the fluid passage through which high-temperature fluid flows during startup is made to flow through low-temperature fluid during steady operation, so that the fluid passage also serves as a fluid passage. You may also do so. Further, the pump for evacuation is not limited to a rotary vacuum pump.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a rotating device in vacuum to which the starting method of the present invention is applied, Fig. 2 is a diagram showing exhaust characteristics when the starting method of the present invention is adopted, and Fig. 3 is a diagram showing the conventional starting method. Fig. 4 is a diagram showing the exhaust characteristics when the conventional startup method is adopted. 1... Vacuum vessel, 4... Motor, 7... Rotary vacuum pump, 13... High temperature fluid supply source. Fig. 1 Il n Fig. 2 Fig. 3 Fig. 4

Claims (3)

[Claims] (1) When starting up a vacuum rotating device consisting of a rotating electric machine installed inside a vacuum container, after evacuation of the inside of the vacuum container to a predetermined pressure while heating the outer surface of the vacuum container with high-temperature fluid, A method for starting a rotating device in a vacuum, characterized in that the rotating electric machine is driven. (2) The method for starting a rotating device in a vacuum according to claim 1, wherein the high-temperature fluid is made to flow through a passage provided along the outer surface of the vacuum container. (3) The method for starting a rotating device in a vacuum according to claim 2, wherein the passage also serves as a low-temperature fluid passage during steady operation.