JPH0140377Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liquid leakage seal for a rotating surface that suppresses the amount of liquid leakage from a gap between a rotor and a casing of a hydraulic machine, for example.

A conventional liquid leakage seal for a rotating surface will be explained based on FIGS. 1 and 2. Figure 1 is a cross-sectional view of a general flat seal, and Figure 2 is a cross-sectional view of a general threaded seal. Although it can also function as a bearing, it has drawbacks such as being prone to foreign matter getting caught or seizing, and a large amount of leaking liquid considering the gap. The threaded seal is provided with thread grooves 3 in opposite directions on both the corresponding sealing surfaces of the rotating body 1 and the stationary wall 2, which oppose the flow of leaked liquid, making it easy to eject foreign objects even if they get caught, and reducing the contact area even if they come into contact. Since the diameter is small, seizure is unlikely to occur, but the shaft power loss due to the fluid action of the thread groove 3 is large, and it does not function as a bearing, and if it comes into contact with it, it is likely to cause eccentricity or vibration of the rotating body 1 due to bending stress. It has its drawbacks.

The purpose of this invention is to eliminate the above-mentioned drawbacks and improve the liquid leakage seal for rotating surfaces with practical functions.Parallel grooves are provided on the sealing surface of the rotating body, and the corresponding sealing surface of the stationary wall is designed to prevent liquid leakage. The present invention provides a liquid leakage seal for a rotating surface characterized by a structure in which a thread groove is carved in a direction opposite to the flow. In other words, an appropriate number of parallel grooves are provided on the sealing surface of the rotating body in the gap where the rotating body surface faces the stationary wall surface, and if a foreign object is caught in the sealing surface of the stationary wall, the foreign object will rotate. When it rotates with the parallel grooves of the body, it is pushed back in the direction opposite to the direction in which it came in and is ejected.The grooves on both sides intersect in a lattice pattern to block the flow, so (a) Foreign matter is ejected. The properties are much better than flat seals.

(b) Shaft power loss is extremely low compared to conventional screw seals.

(c) The amount of liquid leaked is smaller than that of a flat seal.

(d) Like conventional screw seals, seizing is unlikely to occur even if they come into contact.

(e) Although it does not have a bearing function, eccentricity and vibration are less likely to occur when there is contact compared to conventional screw seals.

It has the following effects.

The structure and operation of the present invention will be specifically explained based on an embodiment shown in FIGS. 3 to 5. Figure 3 is a sectional view of the impeller and its surrounding essential parts of a centrifugal pump to which the present invention is applied. It leaks to the bottom pressure side through the gap between the ring 6 and the impeller ring 6', and the gap between the liner ring 7 fitted to the casing 5 and the journal 7' fitted to the main shaft 8. A leakage seal for a rotating surface to which the present invention is applied is provided.

4A is a sectional view of the wear ring 6 in FIG. 3, B is a front view of the impeller ring 6',
Figure 5A is a cross-sectional view of the liner ring 7 in Figure 3, and Figure 5B is a front view of the journal 7'. , the impeller ring 6', and the journal 7' have parallel grooves 3' carved on their outer peripheral surfaces.

Here, when a flow or a foreign substance enters the above-mentioned gap from the high pressure side, both grooves interact so that they are pushed back along the thread groove 3 on the casing 5 side. Since the main shaft 8 side has parallel grooves 3', the hydraulic effect is small and the loss of shaft power is also small. Even if the casing 5 side and the main shaft 8 side come into contact, since both sides are grooves, the contact area is small, and since one side is parallel groove 3', bending stress is also small. The shape of the groove is a square groove so that foreign matter can easily pass through, and the pitch of the thread groove 3 is twice the normal size.
Similar effects can be achieved with other shapes.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a general flat seal, Figure 2 is a sectional view of a general screw seal, and Figure 3 is an impeller of a centrifugal pump equipped with a leakage seal on the rotating surface to which the present invention is applied. 4A is a sectional view of the wear ring in FIG. 3; FIG. 5B is a front view of the impeller ring; FIG. 5A is a sectional view of the liner ring in FIG. 3; B is a front view of the journal as well. 1... Rotating body, 2... Stationary wall, 3... Thread groove,
4... impeller, 5... casing, 6... wear ring, 6'... impeller ring, 7... liner ring, 7'... journal.

Claims (1)

[Scope of utility model registration request] A liquid leakage seal for a rotating surface, characterized in that a parallel groove is formed on the sealing surface of a rotating body, and a threaded groove is carved in the sealing surface of a corresponding stationary wall in a direction opposite to the flow of leaking liquid.