JPS5950876B2 - liquid supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a liquid supply device having a main circuit and an emergency circuit in a liquid supply flow path connecting a liquid supply source and a liquid supply device, and in particular, the pressure of the main circuit can be used to prevent troubles in the regular pump. This invention relates to a liquid supply device that detects this with a pressure detection switch and activates an emergency pump to back up the liquid supply using an emergency circuit.

For example, a seal oil supply device that supplies oil to the bearings of a turbine generator, etc., normally drives a regular seal oil pump 1 on the main circuit side to supply oil from an oil tank 2 to a turbine generator 3, as shown in Fig. 1. The oil is supplied to the bearing section through the check valve 5 and the oil pressure adjustment valve 6, and when trouble occurs on the main circuit side, the emergency sealing oil pump 7 on the emergency circuit side is started to supply oil from the oil tank 2. Oil is supplied to the bearing section of the turbine generator 3 via the check valve 9 and further through the oil pressure regulating valve 6, and the oil supplied to this bearing section is returned to the oil tank 2.

In this case, the regular seal oil pump 1 and the emergency seal oil pump 7
A positive displacement pump is used, and the flow rate is proportional to the pump rotation speed.

Therefore, in order to keep the pressure on the discharge side of both pumps 1 and 7 constant, pressure regulating valves (for example, spring-type relief valves) 4 and 8 are provided between the suction port side and the discharge port side of both pumps. The loop is formed as a pressure regulating circuit.

By the way, conventionally, in such a sealing oil supply device, if a trouble occurs on the main circuit side and the oil pressure suddenly decreases,
This is detected by a pressure detection switch 10 provided on the discharge side of the regular seal oil pump 1, and the detection signal is used to start the emergency seal oil pump 7 on the emergency circuit side.

However, even if the emergency seal oil pump 7 is activated immediately by the detection signal from the pressure detection switch 10, the pressure regulating valve 4 provided between the suction port side and the discharge port side of the regular seal oil pump 1 As a result, the rotational speed and pressure characteristics of the regular sealed oil pump 1 become as shown in FIG. 2C, and it takes too long for the pressure detection switch 10 to detect a decrease in the pressure.

That is, the flow rate Q and pressure P due to the flow resistance from the discharge port side of the regular sealed oil pump 1 to the bearing part of the turbine generator 3
The relationship between the two can be expressed by the characteristics shown in FIG. 2a.

Further, the relationship between the flow rate Q and the pressure P depending on the set value of the pressure regulating valve 4 is represented by the characteristics shown in FIG.

Therefore, the pressure P on the discharge side of the currently used sealed oil pump 1 is taken as the vertical axis, and the number of rotations of the pump (proportional to the flow rate) N is taken as the horizontal axis.
When Figures a and b are combined, the characteristics shown in Figure 2C are obtained.

Therefore, as is clear from the characteristics shown in Figure 2C,
Even though there is a problem on the main circuit side, the pump discharge pressure does not change suddenly unless the pump rotation speed becomes considerably low.

Moreover, if the operating point of the pressure detection switch is set at a point below the normal pump discharge side pressure by ΔP, as shown by the dashed line in Figure 2, the pressure detection switch will be set at a point where the rotational speed of the pump is almost constant. It will not work unless it reaches 0゛, and in this case, there is not enough time for the emergency seal oil pump to increase its rotation, and the pressure will drop temporarily.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a common pump and a discharge port side and a suction port side of the common pump in a liquid supply channel connecting a liquid supply source and a liquid receiving device. A main circuit with a pressure regulating valve that controls the liquid pressure on the regular pump discharge port side to a constant level in the return path connecting the main circuit, and an emergency circuit with an emergency pump in parallel with this main circuit. In the device, a throttling mechanism is provided between the discharge port of the regular pump on the main circuit side and the connection part of the return path connected to this discharge port side to generate a pressure difference between the upstream side and the downstream side. , has an operating value set in a flow path connecting the throttle mechanism and the discharge port of the regular pump to a value that is larger than the set value of the pressure regulating valve and smaller than the upstream pressure of the throttle mechanism under normal conditions; By installing a liquid pressure detector that issues a start command to the emergency pump when it detects that the discharge side pressure of the regular pump has fallen below the operating value, the response of the drop in fluid pressure to the decrease in the rotational speed of the regular pump can be accelerated. It is an object of the present invention to provide a liquid supply device that can significantly shorten the time required to detect a pressure drop due to trouble occurring on the main circuit side.

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

FIG. 3 shows an example of a case where the liquid supply device according to the present invention is applied as a sealing oil supply device for supplying oil from an oil tank to a bearing portion of a turbine generator.

That is, in FIG. 3, 11 is an oil tank containing oil;
Reference numeral 12 denotes a regular sealed oil pump whose suction port is connected to the oil tank 11 and which is driven by a regular pump motor (not shown).
3 is an emergency sealed oil pump whose suction port is connected to the oil tank 11 and driven by an emergency pump motor (not shown);
Both pumps 12 and 13 are displacement pumps similar to those of the past, and their discharge ports are commonly connected through check valves 16 and 17, respectively, and the common connection is connected through a hydraulic pressure regulating valve 18. and is connected to the bearing oil supply line of the turbine generator 19.

Further, a circulation path is formed to guide the oil in the bearing portion to the oil drain line and return it to the oil tank 11 again.

Here, a feedback loop with pressure regulating valves (for example, spring-type relief valves) 14 and 15 provided between the suction port side and the discharge port side of the regular sealed oil pump 12 and the emergency sealed oil pump 13 is used to adjust the pressure. It is formed as a circuit to keep the discharge pressure of both pumps constant.

Also, the check valves 16 and 17 are for preventing backflow of oil supplied to the turbine generator 19 side.

Further, the opening degree of the oil pressure regulating valve 18 is automatically adjusted according to various conditions such as the pressure of the bearing oil supply line of the turbine generator 19 and the rotational speed of the turbine generator 19.

On the other hand, 21 is a throttling mechanism provided in the flow path between the discharge port of the regular sealed oil pump 12 and the connection part of the return path connected to this discharge port side. According to the orifice theory, the pressure is higher than the side pressure.

That is, the pressure on the downstream side of the throttle mechanism 21 is controlled by the pressure regulating valve 1.
4, the pressure on the upstream side is kept at a constant pressure, and the pressure on the upstream side is the constant pressure plus the differential pressure (pressure loss) at both ends of the throttling mechanism, and therefore increases in a square curve as the flow rate increases.

Further, 20 is the discharge port of the regular sealed oil pump 12 and the throttle mechanism 2.
This pressure detection switch 20 is set to a value greater than the set value of the pressure regulating valve 14 and smaller than the upstream pressure of the throttle mechanism 21 under normal conditions. When the pressure on the pump discharge side decreases below the set value, it operates and gives a start command to the emergency pump motor, and the emergency seal oil pump 13
It is what drives the.

Next, to describe the operation of the above configuration, assuming that the regular seal oil pump 12 is currently working normally, the oil in the oil tank 11 is transferred to the regular seal oil pump 12, the throttle mechanism 21. It is supplied to the bearing portion of the turbine generator 19 through the main circuit of the pressure regulating valve 14 and the check valve 16, and further through the oil pressure regulating valve 18.

In this case, the pressure detection switch 20 does not operate because the pressure on the upstream side of the throttle mechanism 21 is higher than its set value, and the emergency seal oil pump 13 does not operate.

In such a state, if a trouble occurs on the main circuit side and the rotation speed of the regular seal oil pump 12 decreases, the fourth
As is clear from the pressure-rotational speed characteristic shown in the figure, the pressure detection switch 20 operates immediately, gives a start command to the emergency pump motor, and operates the emergency seal oil pump 13.

That is, in FIG. 4, if the horizontal axis is the rotation speed of the regular sealed oil pump and the vertical axis is the pressure on the discharge side of the pump, the differential pressure curve between the upstream side and the downstream side of the throttle mechanism 21 will be as shown in C, Further, the pressure on the downstream side of the throttle mechanism 21 is kept constant as shown in a by the set value of the pressure regulating valve 14, similar to the characteristics shown in FIG. The characteristics are similar to the 5 curves obtained by superimposing the C curve on the curve C.

Here, set the pressure detection switch 20 to the pressure regulating valve 14.
If the pressure detection switch 20 is set at a value greater than the set value of , and is lower than the upstream pressure of the throttling mechanism 21 by ΔP in normal conditions, then the pressure detection switch 20 will be set at a point where the rotational speed of the regular sealed oil pump is It operates immediately when it drops a little and starts the emergency pump motor.

Therefore, the emergency seal oil pump 13 is operated before the rotational speed of the regular seal oil pump 12 drops too much.
There is almost no pressure drop in the oil supplied to the turbine generator 19 side, and backup of oil supply through the emergency circuit is performed smoothly.

In the above embodiment, the detection time by the pressure detection switch 20 can be significantly shortened by appropriately adjusting the throttle opening of the throttle mechanism 21.

Furthermore, in the above embodiment, a case was described in which the application was applied to a sealing oil supply device that supplies oil to the bearing part of a turbine generator.
It can be applied to oil supply devices for other electrical equipment, and can also be applied to devices that supply not only oil but also other liquids, such as water, from a liquid supply source to a liquid supply device in exactly the same way as described above. It is possible.

In addition, it goes without saying that the present invention can be implemented with various modifications without changing the gist thereof.

As described above, according to the present invention, a regular pump is installed in the liquid supply flow path connecting the liquid supply source and the liquid receiving device, and a regular pump is installed in the return path connecting between the discharge port side and the suction port side of the regular pump. In a liquid supply device equipped with a main circuit equipped with a pressure regulating valve that controls the liquid pressure at a constant level on the discharge port side, and an emergency circuit equipped with an emergency pump in parallel with this main circuit, the regular pump on the main circuit side A throttle mechanism that generates a pressure difference between the upstream side and the downstream side is provided between the discharge port of the pump and the connection part of the return path connected to the discharge port side, and this throttle mechanism and the discharge port of the regular pump are provided. The flow path connecting the pump has an operating value that is larger than the setting value of the pressure regulating valve and smaller than the upstream pressure of the throttling mechanism under normal conditions, and the discharge side pressure of the regular pump is below the operating value. The structure is equipped with a liquid pressure detector that issues a start command to the emergency pump when it detects that the rotation speed has dropped, making it possible to hasten the response to a drop in liquid pressure in response to a drop in the rotation speed of the regular pump, thereby preventing problems on the main circuit side. A liquid supply device can be provided that can significantly shorten the time required to detect a pressure drop caused by the occurrence.

[Brief explanation of the drawing]

Fig. 1 is a schematic system diagram showing an example of a case where a hydraulic pressure detection device is applied to a sealing oil supply device of a turbine generator, and Fig. 2 is a characteristic curve diagram showing the relationship between pump rotation speed and pump discharge pressure in the same device. , Fig. 3 is a schematic system diagram showing an embodiment of the present invention applied to a sealing oil supply device for a turbine generator, and Fig. 4 shows the relationship between pump rotation speed and pump discharge pressure in the same embodiment. It is a characteristic curve diagram. 11...Oil tank, 12...Normal sealed oil pump, 13...Emergency sealed oil pump, 14
, 15... Pressure regulating valve, 16, 17...
・Check valve, 20...Pressure detector, 21...
...Aperture mechanism.

Claims (1)

[Claims] 1. Liquid pressure on the discharge port side of the regular pump is provided in the liquid supply channel connecting the liquid supply source and the liquid receiving device, and is connected to the regular pump and the return path connecting the discharge port side and the suction port side of the regular pump. a main circuit provided with a pressure regulating valve that controls the pressure at a constant level, an emergency circuit provided with an emergency pump in parallel with this main circuit, and a discharge port of the regular pump and the return path connected to the discharge port side. A throttling mechanism is provided in the flow path between the connecting portion of the pump and generates a pressure difference between the upstream side and the downstream side thereof, and a flow path that connects the throttling mechanism and the discharge port of the regular pump is provided. and has an operating value set to a value larger than the setting value of the pressure regulating valve and smaller than the upstream pressure of the throttling mechanism under normal conditions, and the discharge side pressure of the service pump decreases below the operating value. A liquid supply device comprising: a liquid pressure detector that gives a start command to the emergency pump when it detects that the emergency pump has been damaged.