JPS5874894A - Siphon tube - Google Patents

Abstract

PURPOSE:To enable to reduce the time required for establishing a siphon, by shaping a siphon tube such that it is flattened at its siphon constituting portion to have a sectional area substantially equal to that at the discharge portion of a pump and a height smaller than the critical water head transferring to the discharge flow of the siphon. CONSTITUTION:A siphon tube 4 is flattened at its siphon constituting portion 4a to have a section area A2 substantially equal to that A1 at the discharge portion 2a of a pump 2 and a height smaller than the critical water head (h) transferring to the discharge flow of the siphon. By employing such an arrangement, the siphon tube 4 can be filled with water, with no air left at the upper portion of the tube 4, so that the siphon can be established in an extremely short time. At the same time, the total water head required for establishing a siphon, represented as H'1+H2 in the drawing, can be reduced as compared with those of the conventional arrangements. Resultantly, the shaft power required for establishing a siphon can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a siphon tube used in chamber-shaft axial flow pumps and mixed flow pumps.

As shown in FIG. 7, in the conventional siphon tube l of this kind, the cross-sectional area of the siphon forming part was formed into a circular shape that was the same as the cross-sectional area of the discharge part of the pump 2, so that a jet flow as shown by the solid line B was generated. Therefore, the total lifting height H required for siphon formation is
s +H* (where Hl is the water absorption level and H! is the discharge water level) increases. In addition, an air pocket 3 is generated in the upper part of the jet flow B, and it takes a long time to reach the full flow, and sometimes the flow does not reach the full flow.

The present invention aims to eliminate the above-mentioned drawbacks.
The siphon forming part is formed into a flat shape having a cross-sectional area approximately the same as the cross-sectional area of the pump discharge part, and its height is set below the critical water depth for transition to a jet flow. .

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

In Fig. 2, 4 is a siphon tube connected to the pump 2, and the siphon forming portion 4 of this siphon tube 4 has the same cross-sectional area as the cross-sectional area A1 of the discharge portion 2a of the pump 2! It is formed in a flat shape and its height is set below the critical water depth at which the water transitions to a jet flow.

Since this embodiment is configured as described above, the siphon tube 4
Because there is no air pocket at the top of the inner flow and the flow is full,
Siphons can be formed in a very short time. At the same time, the total lift required to form a siphon becomes H, +H, which is smaller than the total lift Ht +H snow in the conventional example shown in FIG.

! Figure 3 shows a comparison of the characteristics of this embodiment and the conventional example, where solid lines C and E indicate the total lift and required shaft power of this embodiment, respectively, and the two-dot chain line indicates the total lift and required shaft power, respectively.

F indicates the total lift and required shaft power of the conventional example, respectively.

As is clear from this figure, according to this embodiment, both the total lift and the required shaft power can be made smaller than in the conventional example.

tiThis embodiment has a large cross-sectional area of the ion forming portion 4a! The cross-sectional area A of the pump discharge portion 2a is formed to be the same as that of the pump discharge portion 2a, thereby avoiding sudden changes in the cross-sectional area.

It is possible to prevent piping loss from increasing.

As explained above, according to the present invention, it is possible to reduce the shaft power necessary for forming the siphon, and also to downsize the pump and reduce costs.

This significantly reduces the time required for siphon formation.

The pump can be started up quickly.

[Brief Description of the Drawings] @ Figure 1 is a usage state diagram of a conventional siphon tube, Figure 2 is a usage diagram showing one embodiment of the siphon tube according to the present invention, and Figure ai3 is a usage state diagram of this embodiment and the conventional example. It is a characteristic comparison diagram. 2a...Pump discharge part, 4...Siphon pipe%4a
...Siphon formation part. TJ2 Figure U Rage 0r

Claims (1)

[Scope of Claims] The siphon forming portion is formed into a flat shape having a cross-sectional area that is approximately the same as the cross-sectional area of the pump discharge portion. A siphon tube whose height is set below the critical water depth for transition to jet flow.