SU935647A1 - Vertical pump unit - Google Patents

Description

(54) VERTICAL PUMP UNIT

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The invention relates to hydraulic engineering, more specifically to devices for balancing axial force in high-performance centrifugal pumps.

The vertical pumping unit is known; it contains a centrifugal pump with a cantilever impeller and a block of mechanical seals of the pump shaft connected via a pipeline to the locking fluid supply system, and an external U drive with the drive shaft 1 located in its casing.

The axial forces generated by the operation of the unit are perceived by the thrust bearings, which are large in size and weight. This causes an increase in the metal consumption and the power consumed by the bearings during the operation of the unit and the increased starting power of the drive.

Also known is a vertical pumping unit, comprising a centrifugal pump 20 with a cantilever impeller and a block of mechanical seals of the pump shaft, connected via a pipeline to the locking fluid supply system, an external

an actuator, in the case of which, provided with an upper lid, an actuator shaft is located, and a relief element for balancing the axial force 2.

In this construction, the discharge element is made in the form of an electromagnet attracting a disk located on the shaft. Such a structure is characterized by insufficient reliability of the operation of the unit, complexity of its design and installation.

The aim of the invention is to improve the reliability of the unit, simplifying its design and installation.

The goal is achieved by the fact that a throttling element is installed in the pipeline, a bore is made in the lid of the drive housing, and an end of the drive shaft is located in its cavity, the bore cavity is sealed around the shaft by means of additional mechanical seals and connected to the locking fluid supply system, and the discharge element is shaft end with additional seals, h

FIG. 1 shows a vertical pump unit, a longitudinal section; on

FIG. 2 - pump shaft seal on an enlarged scale; in fig. 3 - additional seal located on the drive shaft.

Vertical pumping unit contains a centrifugal pump 1 with a cantilever impeller 2 and blocks of mechanical seals 3 of shaft 4 of pump 1 connected via pipeline 5 to locking fluid supply system, remote actuator 6, in case 7 of which is fitted with an upper cover 8 a drive shaft 9 is located 6, and a discharge member 10 for balancing axial forces. A throttling element 11 is installed in the pipeline 5, a bore 12 is made in the lid 8 of the housing 7 of the drive-6, and an end face 14 of the shaft 9 of the drive 6 is located in its cavity 13, the cavity 13 of the bore 12 is sealed by shaft 9 by means of additional mechanical seals 15 and connected to the system supplying the locking fluid, and the discharge element is the end 14 of the shaft 9 with additional seals.

Each of the seals 3 of the shaft 4 of the pump 1 contains (Fig. 2) a fixed element 16 and a rotating element 17 mounted on the shaft 4. In block 3 there is a chamber 18 to which the locking fluid is supplied. The difference in the diameter of the seal 3 and the diameter p.2 of the shaft 4 of the pump (Fig. 2) determines the area on which the fluid pressure acts in the chamber 18.

Each additional mechanical seal 15 (FIG. 3) installed in the cavity 13 of the bore 12 also contains a fixed element 19 and an element 20 rotating with the shaft 9, similar to elements 16 and 17, respectively. The diameter of the discharge element is equal to Ij. This diameter determines the area of the discharge element, which is influenced by the pressure of the discharge liquid entering the cavity, 13.

To collect leakage of the locking fluid through the additional seals 15, a lid 8 is installed in the lid 8, which is in communication with the chamber of free draining of the locking fluid from the sealing unit 3 (not shown).

An additional pipe 22 serves to supply the locking fluid to the cavity 13 of the bore 12. The stationary elements 16 and 19 of the plates 3 and 15 are sealed with rubber rings 23.

The unit works as follows.

When the pump 1 is in operation, an axial force occurs, directed towards the drive 6.

For axial unloading of the pump 1, the blocking fluid is supplied simultaneously to the cavity 13 of the bore 12 and to the chamber 18 of the sealing block 3 of the shaft 4 of the pump 1. Depending on the ratio of the ring width to width)). which is affected by pressure P | fluid in chamber 18, and a circle with diameter j, which is acted upon by pressure P2 of fluid in cavity 13, the magnitude of pressure P, is controlled by means of a throttling element 11, so that the resultant force is directed towards the axial force to compensate for the latter.

An important advantage of the proposed unit in comparison with the known one is that in case of emergency repair of the unloading element 10, the drive 6 of the pump 1 is not required to be dismantled, as was required in an electromagnetic discharge pump, i.e. the pump meets the requirements of maintainability.

This is especially important for main circulation pumps operating under radiation conditions.

Claims (2)

1.Sinev N.M., Udovichenko P.-M. Sealed water pumps. M., ATOMi 3d, 1972, p. 215, fig. 3.43. 2. In the same place 205-207, fig. 3.38, 3.39. 17 U 23 18 ; j  Ft