JPS6047480B2 - pump equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump device configured to take in water to be supplied to a shaft seal device from the rear shroud side.

Conventionally, in order to seal the rotating shaft that penetrates the casing and connects to the pump runner, a stub interbox is provided at the part that penetrates the rotating shaft, and this stub interbox takes in and supplies water from the rear shroud side of the pump runner. It is necessary to proceed. At this time, in order to lead water to the stub interbox, a hole was made in the casing on the rear shroud side of the pump runner, and a water conduit pipe communicating with the stub interbox was connected thereto. Furthermore, in a cast casing, a water guide hole was drilled from the inner surface of the casing on the rear shroud side of the pump runner toward the stub interbox. However, the former structure requires a large number of parts and is expensive. Furthermore, according to the latter method, it is necessary to perform very deep 16-mm machining, which makes machining extremely difficult. Furthermore, in a single-suction type centrifugal pump or the like, an axial load is generated when the pump is operated, which places a large burden on the bearing device. Therefore, in such cases, attempts have been made to cancel the axial load by providing a balance hole in the pump runner or providing a partition plate on the inner surface of the casing facing the front shroud of the pump runner. However, the balance hole does not have a sufficient effect, and the partition plate causes the axial load to change drastically from negative to positive depending on the pump's discharge volume, which in turn affects the bearing device. The burden could not be reduced sufficiently. Therefore, the present inventors developed a pump device that can easily drill a water introduction hole into a stuffing box, and that can sufficiently cancel out the load applied in the axial direction and reduce the burden on the bearing device. We repeatedly considered whether there was a structure for this.

This will be explained below with reference to one embodiment of the present invention shown in the drawings.

In the figure, reference numeral 1 denotes a pump runner, which is fixed to the tip of a rotating shaft 2. 3 and 4 are the rear shroud and front shroud of the pump runner 1, and 5 is a balance hole.

6 and 7 are a back casing and a front casing that cover the pump runner 1, and the front casing 7 is further provided with a suction port 8 and a discharge port 9.

Reference numeral 10 denotes a water guide hole, which is drilled in the rear casing 6 so that a part of the water on the rear shroud 3 side can be supplied to a stuffing box (not shown) provided at the part where the rotating shaft 2 passes through the rear casing 6. It is something.

In this way, in order to take in water to be supplied to the shaft sealing device, the rear shroud 3 of the pump runner 1 is attached to the rear casing 6.
The opening extends across the inner surface of the rear casing 6 facing the rear casing 6 and the outer peripheral surface of the rear casing 6, and the tip thereof is stuffed.

By providing a groove 11 having a water guide hole 10 that communicates with the water guide hole 10, the distance between the water guide holes 10 can be shortened, and drilling of the groove can be simplified. However, if such a groove 11 is provided, the load placed on a bearing device (not shown) will increase. That is, as shown by curve A in FIG. 3, as the discharge amount Q of the pump device changes, the load F applied in the axial direction varies greatly while staying within a high value range. In order to counteract this axial load, a partition plate 12 is installed on the inner surface of the front casing 7 facing the front shroud 4 so as to stop the flow of water swirling along the rotation direction of the front shroud 4.
It is conceivable to provide a However, the front casing 7
By simply providing the partition plate 12 on the inner surface of the pump, it is possible to reduce the load F acting in the axial direction only in a range where the discharge amount Q of the pump device is small, as shown by curve B. As a result of repeated experiments under various conditions, the present inventors came to the following conclusion.

) In other words, in order to take in water to be supplied to the shaft sealing device,
It opens across the outer peripheral surface of the back casing 6 and the surface facing the back shroud 3 of the pump runner 1, and
Water guide hole 1 whose tip communicates with the stuffing box
A partition plate 12 is provided to stop the flow of water swirling along the front shroud 4 of the pump runner 1 on the inner surface of the front casing 7 located on the opposite side of the groove 11 with the main planner 1 in between. By doing so, such problems can be solved.

Here, the groove 11 can be constructed by selecting a shape or size that facilitates subsequent drilling and casting at the same time as the back casing 6. Further, the partition plate 12 can also be constructed by being cast simultaneously with the front casing 7. In this way, when the groove 11 and the partition plate 12 are placed in positions facing each other with the pump runner 1 in between, the load F acting in the axial direction becomes a small value regardless of the discharge amount Q, as shown by the curve C. Become. This is thought to be because the loads applied in the axial direction cancel each other out as follows. First, when the water swirling along the direction of rotation of the back shroud 3 flows into the groove 11, the flow of water is stopped, and the dynamic pressure of the water turns into static pressure that pushes the pump runner 1 in the direction of arrow a. . Similarly, when water swirling along the direction of rotation of the front shroud 4 hits the partition plate 12 and is stopped from swirling, the dynamic pressure of this water turns into static pressure that pushes the pump runner 1 in the direction of arrow b. In this way, the forces acting in the directions of arrows a and b are applied to cancel the axial load generated on the pump runner 1 by sucking water, and the discharge amount Q is reduced as shown by curve C. It is thought that this is to reduce the load F applied in the axial direction to a small, almost constant value in response to changes. Furthermore, if the groove 11 and the partition plate 12 are provided in a position other than the position where they face each other with the pump runner 1 in between, the groove 11 and the partition plate 12 will be separated by the arrows a.
It is thought that a phase difference occurs in the force generated in the direction of arrow b, and this increases the load F acting in the axial direction.
Such grooves 11 or partition plates 12 only require a slight change in the mold in which the back casing 6 and front casing 7 are cast, and do not increase the number of work steps.

As is clear from the above description, the pump device of the present invention includes a rotating shaft, a pump runner fixed to the rotating shaft and having a front shroud and a back shroud, and an opening on the back shroud side of the pump runner. a front casing that includes a front shroud of the pump runner and covers a front shroud of the pump runner;
In a pump device equipped with a back casing equipped with a stuffing box that houses a shaft sealing device that closes the opening of the front casing and guides out the rotating shaft, water to be supplied to the shaft sealing device is taken in and the machining distance of the water guide hole is shortened. In order to do this, there is a groove that opens across the outer circumferential surface of the rear casing and the surface facing the rear shroud of the pump runner, and has a water guide hole whose tip communicates with the stuffing box, and a groove with the pump runner in between. A partition plate is provided on the inner surface of the front casing located on the opposite side to stop the flow of water swirling along the front shroud of the pump runner.

Therefore, according to the present invention, not only can the machining of the pump device be simplified, but also the load acting in the axial direction can be reduced to a small degree, reducing the load on the bearing device, extending the life of the bearing device, and making it more compact and compact. This allows for weight reduction.

[Brief explanation of the drawing]

Fig. 1 is a part of a sectional view from the front showing one embodiment of the present invention, Fig. 2 is a part of a sectional view from the same side, and Fig. 3 is the same discharge amount Q and axial direction. This is a diagram for explaining the relationship between load and weight F. 1... Pump runner, 3... Rear shroud, 4... Front shroud, 6, 7...
...Casing, 11...Groove, 12...
...Partition board.

Claims (1)

[Claims] 1. A rotating shaft, a pump runner fixed to the rotating shaft and having a front shroud and a back shroud, and an opening that opens the back shroud side of the pump runner and covers the front shroud of the pump runner. In a pump device comprising a front casing and a back casing provided with a stuffing box for accommodating a shaft sealing device that closes an opening of the front casing and guides out the rotating shaft, the back casing is provided with a stuffing box for taking in water to be supplied to the shaft sealing device. a groove that is open across the outer circumferential surface of the casing and a surface facing the rear shroud of the pump runner and has a water guide hole whose tip communicates with the stuffing box; and a groove that is opposite to the groove with the pump runner in between. A pump device characterized in that a partition plate is provided on an inner surface of the front casing located on the side to stop the flow of water swirling along the front shroud of the pump runner.