JPS60596B2 - Forced lubrication head tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When the bearing of a rotating machine uses a forced lubrication system, when its oil supply source is cut off, the rotating machine also cuts off its drive source.

In other words, it is a trip of a rotating machine. In this state, a head tank is often used to supply bearing oil to the rotation of the rotary machine due to inertia.

The present invention relates to an improvement of this head tank. Forced lubrication equipment for bearings in high-speed, large rotating machines such as steam turbines, turbos, and axial flow compressors is used to prevent bearings from burning out when the oil pump stops due to a power outage or breaks down. ,
The rotating machine must be brought to an emergency stop.

Normally, it trips automatically due to safety instrumentation, or even if it is stopped, it takes time to stop because the rotating machine rotates due to the inertia of the rotating machine. In the case of large rotating machines, some rotate for a long time, several minutes, before stopping, and the head tank required during this period has an extremely large capacity. For this reason, there are methods that do not require a head tank, such as having a pump directly connected to the shaft of the rotating machine, but head tank systems are increasingly being adopted because the structure is complex and can cause failures. How can I reduce the capacity of this head tank?
The present invention solves the problem of whether or not it can last for the necessary time. When the rotating machine trips, the time until it stops and the rotational speed are as shown in FIG. 2, and the rotational speed decreases with time. The actual amount of oil required at this time is as shown in Figure 3-a, but in a conventional head tank as shown in Figure 4-d, the relationship between the amount of discharge and the stop time is as shown in Figure 3-d. Therefore, a head tank with a large capacity was required. An improved version of this is a liquid injection head tank as shown in Fig. 4-c, but the relationship between the amount of released oil and the stop time is as shown in Fig. 3-c or c'; Although the capacity can be reduced, it is still far from satisfying the various conditions. The ideal relationship between the amount of released oil and time is as shown in Figure 3-a, and the ideally shaped liquid column tank that achieves this amount of released oil is the shape shown in Figure 4-a.
The bottom area is very large.

As an example, the liquid level height is 5.7 m, and the initial released oil amount is 240 m/s.
min, bottom diameter D for machines that require 2 minutes to stop
The length is 6 to 7 m, which is not practical.

The present invention attempts to accommodate this with a diameter of 1'1. Figure 1 is a system diagram of a forced lubrication oil system with a head tank for tripping. 1 is the rotating machine, la is its bearing, 2 is the main oil tank, 3 is the oil pump, 4 is the oil cooler,
5 is an oil filter, 7 is a restriction orifice, 6 and 8 are check valves, 9 is a head tank for tribbing, and 10 is an overflow pipe for tank 9.

When the oil pump 3 is first started, the oil sucked up from the main oil tank 2 is pressurized by the oil pump 3, passes through the oil cooler 4, oil filter 5, and check valve 6, and then reaches the bearing of the rotating machine 1. La is refueled. A portion of the oil passes through the restriction orifice 7 and is stored in the head tank 9, and when this reaches a certain level, it flows through the overflow pipe 10 to the oil chamber pipe and is returned to the tank 2. At the time of tripping, oil is supplied from the tank 9 to the bearing la through the check valve 8. Figure 5 is the first
1 shows a longitudinal section of a head tank 9' according to the present invention, which is installed in place of the head tank 9 shown in the figure. This tank is a basic tank 1 having the required head and capacity capable of refueling during the initial or first half of the rotation duration of the rotating machine after the rotating machine has tripped.
1, and an auxiliary tank 12 having a head and capacity capable of refueling for the remaining period. Therefore, base tank 11
The tank has a high height and a small diameter, and the auxiliary tank has a low height and a large diameter.The base tank 11 is an open type with a pent 16 at the top, and the auxiliary tank 12 is a closed type. The bottom of the base tank 11 is higher than the bottom of the auxiliary tank 12, and the two bottoms are connected by a passage 13.
The top of 2 is connected to the base tank 11 with a check valve 14 that only allows outflow from the tank. In the figure, the base tank 11 and the auxiliary tank 12 are concentric, and the second auxiliary tank 12
′ are also placed concentrically. and auxiliary tank 12'
The bottom surface of the tank is lower than the bottom surface of the auxiliary tank 12, and both bottom surfaces are connected by a passage 13'. This head tank 9'
The supply of oil to the auxiliary tanks 12, 12' is the same as that described with reference to FIG. 1, and at this time, the auxiliary tanks 12, 12' are filled with oil by opening the check valve 14. At the time of drip, the head tank 9' operates as follows.

The oil stored in the base tank 11 flows down from the head while sucking air from the vent 16. The rotation speed of the rotating machine 1 decreases rapidly after the trip, but since the brake of the rotating machine is due to wind damage and bearing friction, the rotation continues for a longer time as the speed decreases. The lubricating oil required at this time is for preventing heat generation in the bearing, and may be at a ratio of 1.5 to the square of the rotational speed. Also, the amount Q of oil discharged from the head tank is reduced by 1 to 2 proportions of the head, although it depends on the structure of the bearing, so the diameter of the base tank 11 should be set to approximately match this required amount of oil.
When the oil level in the base tank 11 drops to the passage 13, that is, when the oil level in the base tank 11 reaches the level of the passage 13, the auxiliary tank 1
The oil from No. 2 begins to flow down from the passage 13 while replacing it with air. In this way, the base tank 11 takes charge of lubrication during the initial or first half of the inertial rotation duration of the rotary machine with the required head and its tank capacity, and when the base tank 11 is filled with oil, the oil in the auxiliary tank 12 begins to flow down. This will take care of the rest of the rotation duration of the rotating machine. If there are several auxiliary tanks, connect them in parallel at the bottom with their bottom heights lowered one after another. In this way, the auxiliary tanks will work one after the other, increasing the refueling time, satisfying the required time, and as shown in Figure 3, which is similar to the ideal relationship graph between required oil amount and time, Figure 3-a. It is possible to obtain performance similar to b. This is the fourth
The figure shows a subordinate head tank d and a liquid column type head tank c.
, and the head tank b according to the present invention are as follows as an example. Initial oil amount 240min
Assuming that the liquid level in the head tank is 5.7 m, the duration is 20 minutes, and the amount of released oil Q is proportional to the height, the capacity comparison is approximately b: c: d = 1: 12: 23 degrees. become. Although the tank of the present invention is inferior to the theoretical value due to ease of manufacture, it still produces a difference of about b:c:d=1:4.5:9, and the tank of the present invention is considerably advantageous. I understand that. In other words, by dividing the head tank into the tank responsible for the first half of the period of rotation due to inertia after a trip and the tank responsible for the remaining period as described above, the capacity of the head tank can be made considerably smaller. . In the figure, the base tank 11 and the auxiliary tank 12 are shown concentrically, but the same effect can be achieved even if they are installed separately with a step in the bottom height and connected at the bottom with a connecting pipe.

[Brief explanation of the drawing]

Figure 1 is a schematic system diagram of the forced lubrication system, Figure 2 is a conceptual graph of rotation speed and stop time during an emergency stop, Figure 3 is a graph of the relationship between the oil amount of various types of turrets and the time until stop, a: theoretical value. , b: In the case of the head tank of the present invention, c, c': In the case of the liquid column type head tank, d: In the case of the conventional head tank, Figure 4 shows the size and shape of the head tank when refueling is carried out for the same time. Comparison diagram, a: ideal shape, b: mold according to the present invention,
c: liquid column type, d: conventional type, FIG. 5 is a conceptual diagram of the head structure of the present invention, and FIG. 6 is a diagram of the same air displacement state. 1... Rotating machine, 2... Main oil tank, 3... Oil pump,
4...Oil cooler, 5...Oil filter, 6.8,1
4...Check valve 7...Restriction orifice, 9,9'...Head tank, 10,15...Overflow pipe, 1 line...Base tank, 12,12'...Auxiliary tank, 13...Oil passage 16
···Bento. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. An open type base tank having the required head and capacity for refueling during the initial or first half of the period of rotation due to inertia after the rotary machine's drive source is cut off, and for refueling for the remaining period. A closed type auxiliary tank having the required head and capacity for water is connected at the bottom with the bottom of the base tank being higher than the bottom of the auxiliary tank, and the top of the auxiliary tank is equipped with a check valve that only allows outflow from the tank. Forced lubricating oil head tank connected to the base tank.