FI68296B - RELEASE FOR ROTATION AV ROTATION IN MOTOR RIKTNING AVN VERTIKALPUMPS AXEL - Google Patents

Description

! 68296

The present invention relates to pumps and in particular to devices for preventing the rotation of the shafts of vertical pumps in the opposite direction. Po. the invention can be best utilized in the main circulation pumps of nuclear power plants. One of the most important problems in this case is the prevention of the rotation of the stopped pumps in the opposite direction, the rotation of which is caused by the backflow of the working fluid.

When one or more pumps in a group operating with a common collector are stopped, the flow of pumped liquid tends to rotate in the opposite direction the shafts of the stopped pumps.

15 There are various difficulties in rotating the pump shaft in the opposite direction, namely the following: - a large driving torque is required to start the reversing pump; the pump must use reversing bearings; pumps he winding parts undergoes additional wear.

Various devices have been used to prevent the shaft of the vertical pumps from rotating in the opposite direction. A pump is already known in the art (see NM Suniovin, PM Udovichenko's book "Water pumps without sealing sleeves", "Atomizdat", 1975, p. 122, Fig. 239) through the impeller of the backflow door and thus prevents the pump shaft from rotating in the opposite direction at the inlet pipe connection which it closes when the fluid flows back. When using 30 of these valves in the described pumps, the problem is the poor reliability of the valve operation in the radioactive liquid flow and the difficult preventive maintenance and repair of the valve in conditions with high radioactivity.

2 68296

Another device that prevents the vertical pump shaft from rotating in the opposite direction is more reliable (see NM Syniov, PM Udovichenko's book "Water pumps without sealing sleeves", Moscow, ed. "Atomizdat", 1975, p. 213) The device comprises 5 fixed circlips and locking parts which is suspended freely on horizontal spindles attached to a shaft. The spindles on which the locking parts are suspended are arranged radially with respect to the geometric axis of the shaft. When the pump is operating, the sliding locking members slide over the teeth of the locking ring 10, allowing the shaft to rotate. When the pump is stopped, the locking parts engage with the teeth of the circlip, which prevents the shaft from rotating in the opposite direction.

In use, however, the locking members continuously slide over the teeth of the locking ring, resulting in premature wear of the teeth and the locking-15 members.

Po. The main object of the invention is to develop a device which prevents the shaft of the psychic pump from rotating in the opposite direction and in which the locking parts are arranged so that they do not touch the teeth of the locking ring during operation of the pump.

To this end, a device has been developed which prevents the shaft of a vertical pump from rotating in the opposite direction and comprises a fixed circlip and locking parts for engaging with the teeth of the circlip and suspended freely on horizontal shafts attached to the shaft. the locking portions are positioned perpendicular to the lines extending through the geometric longitudinal axis of the shaft. As the shaft rotates, the locking parts are bent by the centrifugal force due to this structure, leaving them in contact with the teeth of the locking ring, so that the device is not subject to wear.

The invention will now be described in more detail with reference to a particular embodiment related to the accompanying drawings, in which: Figure 1 shows a schematic longitudinal view of a device according to the invention which prevents the shaft of the vertical pump 3 68296 from rotating in the opposite direction; and Figure 2 shows a cross-sectional view taken along line 11-11 of Figure 1.

The device for preventing the shaft 5 of the vertical pump from rotating in the opposite direction comprises a locking ring 1 (Fig. 1) mounted on the pump cover 2, locking parts 3 suspended freely on horizontal spindles 4 fixed by brackets 5 on the shaft 6. Locking parts 3 (Fig. 2 ) is operatively connected to the teeth 7 of the snap ring 1 10. Each spindle 4 is positioned perpendicular to a straight line 00 extending through the geometric longitudinal axis of the axis. The teeth 7 of the locking ring 1 are chamfered in a direction opposite to the normal direction of rotation of the shaft 6 shown by the arrow in the drawing.

When the pump is stopped, the locking parts 3 (Fig. 1} settle in a vertical position with their own weight and engage with the teeth 7 of the locking ring 1 as shown in Fig. 2. In this state the pump shaft 6 is locked in the opposite direction, which could follow the pumped liquid flow. when started, the shaft 6 starts to rotate and the locking parts 3 sliding over the bevels of the teeth 7 begin to deviate from the shaft 6 around the spindles 4, allowing it to rotate. 3, the latter deviate from their direction around the spindles 4 and settle in the positions shown in Fig. 1 by dashed lines (Fig. 1}, whereby the contact between the teeth 7 and the locking parts 3 of the locking ring 1 is removed.This is the position of the locking parts 3 during pump operation.

When the pump is stopped, the rotational speed of the shaft 6 decreases and the centrifugal force acting on the locking parts 3 decreases accordingly. The locking parts 3 lower with their own weight 35 and begin to slide over the bevels of the teeth 7 of the locking ring. When the shaft 6 stops, the locking parts 3 engage with the teeth 7 and lock the shaft 6, thus preventing it from rotating in the opposite direction due to the flow of the pumped liquid.