JPS62280506A - Method of operating condensate booster pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to the operation of a condensate boost pump, and in particular to a condensate boost pump suitable for the combined operation of a regular pump and a standby pump. It concerns pump operation methods.

[Conventional technology]

Conventionally, as a method of operating a condensate boost pump, for example, as shown in JP-A-57-161406, the rotation speed of the pump during operation is controlled by driving the condensate boost pump with an electric motor equipped with a fluid coupling. Efforts are being made to keep the differential pressure of the deaerator water level regulating valve, which is installed downstream of the pump, constant by controlling the pump, thereby preventing damage to the regulating valve due to noise, vibration, and cavitation erosion. Ta.

This method makes it possible to control the rotation speed of the condensate boost pump by interposing a fluid coupling, whereas the electric motor is driven at a constant rotation speed. When a spare machine was installed in a pump, the spare machine was not equipped with a fluid coupling because of the frequency of use of the spare machine and the economical problems caused by the installation of a fluid coupling.

This means that when one of the multiple condensate boost pumps installed stops or breaks down, in the process of operating the condensate boost pump, that is, the regular machine and the standby machine, the standby machine is Due to the structure, constant rotation is performed at all times, so the outlet of the standby machine is higher than that of the regular machine, and as a result, the regular machine must be operated in combination by increasing its rotational speed to the rated speed.

[Problem that the invention seeks to solve]

The above conventional technology takes into account the fact that a backup unit driven by an electric motor is installed in the condensate boost pump, and that the regular unit and the backup unit are operated together when one of the multiple condensate boost pumps stops or breaks down. has not been done.

Since the backup machine always rotates at a constant speed, the regular machine had to be operated at the same speed as its rated speed. For this reason,
During combined operation, the fluid coupling of the regular machine is inhibited from its rotational speed control function, and the adjustment of the deaerator water level, that is, the condensate flow rate, must depend on the deaerator water level adjustment valve. This means that during combined operation, especially when the condensate flow rate decreases during low-load operation, the differential pressure across the regulating valve increases,
There was a problem that there was a risk of damage due to valve noise, vibration, and cavitation erosion.

An object of the present invention is to control the regulating valve by providing a regulating valve at the outlet of the standby machine when the regular machine and the standby machine are operated together, and to control the deaerator water level regulating valve without causing an increase in the rotational speed of the regular machine. The purpose is to keep the differential pressure constant and ensure stable plant operation during combined operation.

[Means for solving problems]

The above purpose is to install a regulating valve at the outlet of the standby machine separately from the deaerator water level regulating valve installed downstream of the standby machine of the condensate boost pump, and to control the water level of the deaerator and Condensate flow rate/
This is achieved by providing a computing unit that corrects and calculates each signal of the water supply flow rate, and a regulating valve controller that adjusts the air pressure to operate the regulating valve based on the conversion signal from the computing unit.

[Effect]

In the present invention, when the regular machine and the standby machine are operated together, the regulating valve at the outlet of the standby machine uses a conversion signal that is corrected by the signal from the water level of the deaerator and the signals from the condensate flow rate and the feed water flow rate. It will be controlled by the aforementioned regulating valve controller. As a result, the outlet pressure of the regulating valve becomes the same as the outlet pressure of the regular machine due to the rotational speed of the fluid coupling that corresponds to the condensate flow rate required during combined operation in the regular machine, ensuring stable operation during combined operation. The differential pressure of the air water level control valve is kept constant.

〔Example〕

An embodiment of the present invention will be described below. FIG. 1 is a system diagram showing a condensate boost pump operating method according to the present invention. The steam that has completed its work in the steam turbine (not shown) is transferred to condenser 1.
After being condensed, it is pressurized by a condensate pump 2 driven by an electric motor 3 provided on a pipe 4, and is desalinated in a condensate desalination device 5 and sent to a condensate boost pump 6. . Condensate repressurized by a condensate boost pump 6 driven by an electric motor 8 equipped with a fluid coupling 7 is passed through a condensate flow rate measuring device 9 disposed in the pipe line 4 . Deaerator water level adjustment valve 10. Low pressure feed water heater 11
The water is sent to the deaerator 12 and held there. Further, the water from the deaerator 12 is supplied to the water supply pressure pump 14 disposed in the pipe [3]. The water is fed under pressure to a steam generator (not shown) via a feed water flow meter 15 and a feed water pump 16. In the above-mentioned circulation system, the condensate boost pump 6 is constantly controlled in rotation speed by the fluid coupling 7, and the rotation speed control mechanism of the fluid coupling 7 will be described.

The signal from the deaerator water level detector 23 is sent to the calculator 24, while the signal from the condensate flow rate meter 9 and the feed water flow rate meter 1 are sent to the calculator 24.
Based on the signal from 5, the arithmetic unit 25 sends it to the arithmetic unit 24 as a correction signal. Each of the above-mentioned signals is sent to the rotational speed controller 26 as a conversion signal by the arithmetic unit 24 to control the rotational speed of the fluid coupling 7. That is, when the water level of the deaerator 12 is lower than the set water level, the rotation speed of the condensate boost pump 6 is increased by the fluid coupling 7, and conversely, when the water level of the deaerator 12 is higher than the set water level, the fluid coupling increases the rotation speed of the condensate boost pump 6. 7, the rotational speed of the condensate boost pump 6 is to be decreased. On the other hand, the differential pressure of the deaerator water level regulating valve 1o is detected by the differential pressure detector 21, and this signal is sent to the deaerator water level regulating valve 1 by the differential pressure regulator 22.
The differential pressure of 0 is always controlled to be constant.

The present invention provides the following system configuration and control mechanism in addition to the system configuration and control mechanism described above. A regulating valve 33 is installed at the outlet of a condensate boost pump 31 driven by an electric motor 32. The signal from the deaerator water level detector 23 is sent to the calculator 24, while the signal from the condensate flow rate meter 9 and the signal from the feedwater flow rate meter 15 is sent to the calculator 24 as a correction signal by the calculator 25. It will be done. Each of the above signals is sent as a conversion signal by the computing unit 24 to the regulating valve controller 34 to control the regulating valve 33.

Therefore, in this figure, only one condensate boost pump 6 is shown, but when one of the multiple condensate boost pumps 6 stops or breaks down, the condensate boost pump 6 and the condensate boost backup pump 31 when driving together.

By controlling the regulating valve 33 at the outlet of the condensate pressure boosting preliminary pump 31, the pressure at the regulating valve 33 outlet becomes the same as the pressure at the condensate boosting pump 6 outlet by controlling the rotation speed of the fluid coupling 7.
Further, the degassing water level regulating valve 10 is controlled so that the differential pressure is constant.

Next, the characteristics of the condensate boost pump according to the present invention will be explained with reference to FIG. That is, Fig. 2 is a graph showing the characteristic curve of the condensate boost pump and the condensate flow rate, and as the flow rate G decreases depending on the rotation speed of the fluid coupling, the characteristic curve Po-5 of the condensate boost pump changes to PO to P5. On the other hand, the system head curve Ps is the pressure inside the deaerator plus the pipe line loss and hydrostatic head. In the condensate flow ft G s when the condensate boost pump and the condensate boost backup pump are operated together,
The rotation speed of the condensate boost pump decreases due to the fluid coupling, resulting in a characteristic curve P8. As a result, the outlet pressure of the condensate boost pump becomes H5, which is the combination of the system head PSx when the condensate flow rate is 01 and the differential pressure ΔP1 of the deaerator water level adjustment valve.

Further, the characteristics of the condensate booster backup pump according to the present invention will be explained with reference to FIG. In other words, Fig. 3 is a graph showing the characteristic curve and condensate flow rate of the condensate boosting backup pump. The outlet pressure of the water pressure boosting backup pump becomes H2 according to the condensate pressure boosting backup pump characteristic curve Pa. As a result, the rotation speed of the condensate boost pump must be increased to the rated rotation speed, but the control valve at the outlet of the condensate pressure increase prediction pump is connected to the deaerator water level detector, condensate flow rate meter,
The signals from the feedwater flow rate measuring device are processed and controlled by the regulating valve controller, and the throttle of the regulating valve at the condensate flow rate Gl becomes ΔP2, and the pressure at the outlet of the regulating region is finally equal to the outlet of the condensate boost pump. Hs becomes the same as the pressure of , and there is no need to increase the rotation speed of the condensate boost pump.

As described above, according to the present invention, when the condensate boost pump and the condensate boost reserve pump are operated together, the outlet of the condensate boost pump and the above-mentioned regulator valve is The pressure can be kept low, and the valve differential pressure of the deaerator water level adjustment valve can be kept constant, making it possible to prevent damage caused by noise, vibration, and cavitation erosion. Further, during the above-mentioned combined operation, there is no need to increase the rotation speed of the condensate boost pump to the rated rotation speed, and the power of the condensate boost pump can be reduced.

〔Effect of the invention〕

According to the present invention, a regulating valve is provided at the outlet of the condensate boosting preliminary pump, and this regulating valve can be controlled by signals of the deaerator water level, condensate flow rate, and water supply flow rate. The differential pressure of the deaerator water level adjustment valve is maintained constant when the water booster backup pump is operated in combination, which has the effect of preventing damage caused by noise, vibration, and cavitation erosion.

In addition, during the above-mentioned combined operation, there is no need to increase the rotation speed of the condensate boost pump to the rated rotation speed, so there is an effect of reducing the power of the pump.6 In particular, the present invention provides the above-mentioned effects with excellent economic efficiency. This makes the equipment inexpensive.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a device implementing the condensate boost pump operation method of the present invention, Fig. 2 is a graph showing the characteristic curve and condensate flow rate of the condensate boost pump by the device of Fig. 1, and Fig. 3 is 61 is a graph showing the characteristic curve and condensate flow rate of the condensate boosting preliminary pump using the device shown in FIG. 1; 61... condenser; 3... electric motor;
4... Pipe line, 6... Condensate boost pump, 7... Fluid coupling, 8... Electric motor, 10... Deaerator water level adjustment valve,
12... Deaerator, 13... Pipeline, 24.25...
computing machine.

Claims (1)

[Claims] 1. The condensate boost pump is connected to an electric motor with a fluid coupling installed on the pipe that pressurizes the condensate condensed in the condenser and sends water to the deaerator. In the pump configuration in which the machine is installed, a regulating valve and an arithmetic unit and a controller for controlling the regulating valve are installed separately from the deaerator water level regulating valve installed in the pipeline on the downstream side of the standby machine. , a condensate boost pump operating method characterized in that the above condensate boost pump and a standby unit are operated together.