JPS5885394A - Shaft sealing device for water supply pump to boiler - Google Patents

Abstract

PURPOSE:To facilitate construction of shaft shealing device and enhance the reliability of a feed water pump to a boiler, by equipping the pump with a seal water pressure-boosting impeller on its shaft. CONSTITUTION:Low pressure water discharged from a condensate pump 1 flows into a seal water pressure-boosting pump 16 through a seal water pipe 6 and, upon boosted by the pump 16 to a certain amount higher value than the intake pressure of a boiler feed water pump 4, is supplied to a floating ring 20 through a diffuser 18 and a seal water pipe 19. While the pump 4 is at a standstill, the booster pump 3 is also stopped to reduce the pressure in the pump 4 below the discharge pressure of the condensate pump 1, so that the low pressure water discharged from the condensate pump 1 can serve for sealing even though not boosted by the seal water pressure-boosting impeller 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft sealing device having a floating ring used in a boiler feed pump. Conventional boiler feed pump equipment includes a condensate pump 1. Deaerator2. Booster pump 3I Boiler feed pump 4 and sealing pump 7t - Piping 6,12~1s
The water discharged from the condensate pump 1 is operatively connected through the condensate pipe 12. After flowing into the booster pump 3 through the deaerator 2 and the downcomer pipe 13 and being pressurized, it flows into the boiler feed water pump 4 through the piping 14, where it is further pressurized, and then flows through the piping 15t to the boiler (not shown). Supplied.

A floating ring (not shown) provided on the shaft 5 of the boiler feed pump 4 has a water sealing pipe 6. Seal water is supplied through the seal pump 7 and the control valve 8t.

In this case, in order to prevent the high-temperature water in the boiler feed pump 4 from leaking, the sealing water is raised in advance by the sealing pump 7 to a constant one-direction higher pressure than the internal pressure of the pump 4. . Further, the control valve 8 is controlled by a controller 11, and the controller 11 is a differential pressure oscillator 11 that detects the differential pressure between the rotor balance pipe 9 and the water sealing pipe 6 through which pressure water equal to the suction pressure of the boiler feed pump 4 flows. It is manipulated by the signal sent from the

Furthermore, in the conventional shaft sealing device described above, it is necessary to set up interlocks for starting and stopping the boiler feed water pump 4 and for reducing pressure water in the water sealing pump 7.

The device may become very complex and costly.

In view of the above, the present invention aims to simplify the shaft sealing device and improve its reliability.

A boiler feed pump equipped with a shaft sealing device having a floating ring, characterized in that an impeller for increasing pressure of sealed water is attached to the shaft of the pump, and sealed water pressurized by the impeller is supplied to the floating. It is something.

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

Among the symbols shown in FIG. 2, the same symbols as those in FIG. 1 indicate the same parts.

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

sI2 diagram and l! In Fig. 3, 16 is a water-sealing boosting impeller attached to one end of the boiler feed water pump shaft 5;
is gauging surrounding the impeller 16 and the diffuser 18 provided on the discharge side of the impeller 16, and the casing 17 has a passage 171 connecting the suction port of the impeller 16 and the water seal If6, and a diffuser 1B and a 70-ting ring 20. A passage 17b is used to communicate with the water sealing pipe 19. The rest of the configuration is the same as the conventional example shown in FIG. 1, so the explanation will be omitted.

Next, the operation of this embodiment configured as described above will be explained.

The low pressure water discharged from the condensate pump 1 is sent to the water sealing pipe 6t-
The water then flows into the sealing water boosting pump 16, where it is boosted to a pressure that is a certain value higher than the pressure of the boiler feed water pump 4a, and then supplied to the floating ring 20 via the diffuser 18 and the water sealing pipe 19'. On the other hand, when the pump water supply pump 4 is stopped, the booster pump 3 is also stopped, so the pressure inside the boiler water supply pump 4 becomes lower than the discharge pressure of the condensate pump 1, so the low pressure water discharged from the condensate pump 1 is The water seal is not pressurized by the pressure boosting impeller 16 and can function as a uniaxial seal.

As explained above, according to the present invention, various devices such as a water sealing pump, a water sealing control valve, a differential pressure oscillator, and an interlock circuit in the conventional example are not required.

Simplifies the entire device and improves reliability.

Moreover, the cost can be reduced considerably.

[Brief explanation of the drawing]

Figure 1 is a system diagram of conventional boiler feed water pump equipment. FIG. 2 is a system diagram of a boiler feed water pump equipment equipped with the shaft sealing device of the present invention, and FIG. 3 is a sectional view showing an embodiment of the shaft sealing device of the present invention. 4...Boiler water supply pump, 5...Pump shaft, 16.
・・Impeller for water sealing and boosting pressure, 20・・Floating ring.

Claims (1)

[Claims] In a boiler feed pump equipped with a shaft sealing device having a floating ring, an impeller for increasing the pressure of sealed water is attached to the shaft of the pump, and the sealed water pressurized by the impeller is configured to be supplied to the 70-ring ring. A shaft water sealing device for a boiler feed pump, characterized by: