JPS6345498A - Injection nozzle for jet pump - Google Patents

Abstract

PURPOSE:To prevent the clogging of a nozzle part by opening the nozzle part only when a jet pump is in operation and closing the nozzle part when operation stops. CONSTITUTION:An injection cover 5 is installed onto the periphery of the lower edge part of a transport pipe 1, and can be shifted in the direction of the axis center of a transport pipe 1 by allowing the inner peripheral surface of an outer cylinder 7 to freely slide for the outer peripheral surface of a flange 11. The outer peripheral tapered surface 23 of an inner cylinder 9 is formed into a nozzle part 24 together with the inner peripheral tapered surface 3 of the transport pipe 1, and the nozzle part 24 can be closed by the shift of the injection cover 5. The nozzle part 24 is opened only in the operation of the jet pump, and closed when the operation is suspended. Therefore, the clogging of the nozzle part in the operation stop can be prevented.

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to an injection nozzle for a jet pump. BACKGROUND OF THE INVENTION Jet pumps can be used to lift objects to be pumped up, such as sand that has settled at the bottom of a sand pit or sludge in a pit. Conventional jet pumps, for example, as shown in Utility Application No. 152620/1980, have a suction pipe that opens downward facing the object to be pumped up, such as sand or sludge, and jet water is injected into this suction pipe. Some have an upward injection nozzle that sucks the object to be pumped up into the suction pipe. Problems to be Solved by the Invention However, in conventional jet pumps such as those described in Section 2, the injection nozzle opens upwards, so objects to be pumped up, such as sand, may fall into the injection nozzle, especially when the pump is stopped. There is a possibility that the injection nozzle may be clogged by backflow into the injection nozzle.6 Therefore, it is an object of the present invention to make it possible to prevent the occurrence of such clogging. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides: a transport pipe whose lower end is open when arranged vertically; and a transport pipe arranged around the lower end of the transport pipe. an outer cylinder capable of forming a storage space for driving water between the lower end thereof and an inner cylinder which forms an inlet communicating with the transport pipe and whose upper end surface can come into contact with the lower end surface of the transport pipe. , and is configured to be movable in the axial direction of the transport pipe, and when the upper end face of the inner cylinder and the lower end face of the transport pipe are opened due to this movement, the driving water flows into the transport pipe between these end faces. an injection cover capable of forming a nozzle portion for injecting water; an upper end surface of an inner cylinder of the injection cover can be pressed against a lower end surface of a transport pipe to seal between both end surfaces; and driving water is supplied into the injection cover. and a suppressing means that allows the injection cover to move in a direction in which the two end surfaces are separated from each other based on the hydraulic pressure of the driving water. In this configuration, when the operation is stopped, the upper end surface of the inner cylinder of the injection cover and the lower end surface of the transport pipe are brought into contact with each other by the suppressing means, and the nozzle portion is closed. When driving water is supplied inside the injection cover to operate the jet pump,
The water pressure of the driving water causes the spray cover to move against the pressing force of the suppressing means, and the two end faces are projected toward each other to open the nozzle portion. For this purpose, driving water is injected into the transport pipe from the nozzle portion, and the object to be pumped up, such as sand, is attracted by this driving water and sent from the suction port into the transport pipe. When the operation of the jet pump is stopped, the nozzle portion is closed again by the suppressing means, so that sand and the like do not enter the nozzle portion, and clogging of the injection nozzle is reliably prevented. Embodiment In FIGS. 1 and 2, reference numeral 1 denotes a vertical transport pipe, which is provided, for example, from above the water surface in a settling basin toward a settling pit at the bottom of the settling basin. FIG. 1 shows the lower end of such a transport pipe 1, and 2 is the bottom of the water. The lower end of the transport pipe 1 is open, and an inner circumferential tapered surface 3 that tapers toward the inside of the transport pipe 1 is formed as the lower end surface. 4 is a backwash pipe connected to the transport pipe 1. An injection cover 5 is provided around the lower end of the transport pipe 1 . The injection cover 5 includes an outer cylinder 7 that is arranged along the outer circumference of the transport pipe 1 and can form an annular driving water storage space 6 between the transport pipe 1 and an inlet pipe 7 that communicates with the transport pipe 1. It has an inner cylinder 9 in which an opening 8 can be formed, and the outer cylinder 7 and the inner cylinder 9 are connected by a bottom plate 10. A first flange 11 is fixed to the outer periphery of the lower end of the transport pipe 1 . This first flange 11 is arranged so as to be internally fitted into the upper part of the outer cylinder 7 of the injection cover 5,
The upper part of the accommodation space 6 is closed. A driving water supply pipe 12 to the housing space 6 is connected to the upper surface of the first flange 11 . The injection cover 5 has an outer cylinder 7
The inner circumferential surface of the first flange 11 is slidable on the outer circumferential surface of the first flange 11, so that it is movable in the axial direction of the transport pipe 1. An O-ring 13 seals between the outer cylinder 7 and the first flange 11. Guide stays 14 for guiding the movement of the injection cover 5 penetrate through the first flange 11 at 23 or more positions in the circumferential direction. This guide stay 14 is
Its lower end is embedded in the bottom plate XO of the injection cover 5, and is fixed with a lock nut 15. Flange 1 in guide stay 14

A pipe-shaped spacer IS is externally fitted in the part that passes through [, and this spacer 1
6 and the flange 11 are sealed with an O-ring 17. Transport pipe 1 between first flange 11 and bottom plate 10
A second flange 18 is fixed to the outer periphery of the guide stay 14, and the guide stay 14 passes through the second flange 18. Guide stay 14 above second flange 18
A compression coil spring 19 as a suppressing means that engages with the second flange 18 is provided on the outer periphery of the compression coil spring 19 .
the first washer 20 that engages with the first washer 20, the spacer 16 mentioned above that engages with the first washer 20, and the spacer 1
6 and a second washer 21 that engages with the second washer 21 are fitted in order. Further, a double nut 22 that engages with a second washer 21 is screwed onto the upper end of the guide stay 4. The inner tube 9 has an inner diameter substantially equal to the inner diameter of the transport pipe 1, and has an outer circumferential tapered surface 23 as an upper end surface formed on the outer circumference of the upper end thereof. This outer peripheral tapered surface 23 is configured to be able to form an annular nozzle portion 24 directed toward the inside of the transport pipe 1 with the inner peripheral tapered surface 3 of the transport pipe 1, and also allows movement of the injection cover 5. The nozzle portion 24 is configured to be able to come into contact with the inner circumferential tapered surface 3 and close the nozzle portion 24. In such a configuration, when the jet pump is stopped, the compression coil spring 19 is connected to the washer 20 and the spacer 1.
6 or the like, push the guide stay 14 upward. As a result, the injection cover 5 is moved upward and the spring 1
Both tapered surfaces 3 and 23 are brought into contact with each other by a force of 9,
The nozzle portion 24 is maintained in a closed state. During operation of the jet pump, pressurized driving water 25 is supplied from the driving water supply pipe 12 toward the inside of the accommodation space 6 . Air can be mixed into this pressurized water 25 if necessary. Then, the pressure possessed by this driving water 25 acts on the bottom plate 10 of the injection cover 5, and this acting force overcomes the force of the compression coil spring 19, and the injection cover 5 is moved downward. As a result, the outer circumferential tapered surface 23 of the inner cylinder 9 separates from the inner circumferential tapered surface 3 of the transport pipe 1, the nozzle part 24 is opened, and the driving water 25 is injected into the transport pipe 1 from this nozzle part 24. Then, the object to be pumped up, such as sediment, is sucked by the driving water 25 and sent from the suction port 8 into the transport pipe 1, and is transported upward through the transport pipe 1. The nozzle gap 26 of the nozzle part 24 is formed by a double nut 22.
By adjusting the spring force of the compression coil spring 19, it is possible to obtain an appropriate value. Moreover, the second washer 21 comes into contact with the first flange 11, thereby preventing the nozzle portion 24 from opening excessively. Further, by reducing the height of the inner cylinder 9, the nozzle portion 24 can be positioned close to the water bottom 2, and hot water can be reliably sucked up to objects to be pumped up that exist near the water bottom 2. When the operation of the jet pump is stopped, the water pressure from the drive water 25 is no longer applied, so the injection cover 5 is moved upward by the spring force of the compression coil spring 19, and the nozzle part 2
As soon as the nozzle 4 is closed, objects to be pumped up, such as sand, are prevented from entering the nozzle portion 24 and causing clogging. If a blockage occurs inside the transport pipe 1, pressurized backwash water is supplied from the backwash pipe 4 to the inside of the transport pipe 1 to clean the part where the blockage has occurred. . 3 and 4 show other embodiments of the present invention. In this example, a bottomed cylinder 3 is provided on the lower surface of the second flange 18.
1, an air chamber 32 is provided at the lower outer periphery of the transport pipe 1. In addition, a plurality of air introduction holes 33 are formed in the wall of the transport pipe 1 to communicate the air chamber 32 with the inside of the transport pipe 1. 34 is an air suction pipe to the air chamber 31, which passes through the second flange 18 as shown in FIG.
1 and is open to the atmosphere. According to such a configuration, air is mixed into the driving water 25 due to the ejector effect of the driving water 25 jetted from the nozzle portion 24 . Thereby, wear on the inner surface of the transport pipe 1 is reduced, and an air lift effect can also be exerted. Effects of the Invention As described above, according to the present invention, the nozzle part opens only when the jet pump is in operation and closes when the jet pump is stopped, so that the object to be pumped up does not enter the nozzle part when the jet pump is stopped. Clogging is reliably prevented from occurring.

[Brief explanation of drawings]

FIG. 1 is a sectional view taken from the front of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. Figure 4 shows IV- in Figure 3.
FIG. 1... Transport pipe, 3... Inner peripheral tapered surface (lower end surface), 5
...Injection cover, 7.Outer cylinder, 9.Inner cylinder, 19.
... Compression coil spring (suppressing means), 23 ... outer peripheral tapered surface (upper end surface), 24 ... nozzle part. Agent Yoshihiro Morimoto 1 Figure 2 '422 Figure 3 ゛ -7TT completion 2211

Claims (1)

[Claims] 1. A transport pipe arranged in the vertical direction and having an open lower end, and a driving water storage space formed between the transport pipe arranged around the lower end of the transport pipe and the lower end. and an inner cylinder that forms a suction port that communicates with the transport pipe and whose upper end surface can come into contact with the lower end surface of the transport pipe, and is configured to be movable in the axial direction of the transport pipe. and an injection cover capable of forming a nozzle portion between the upper end surface of the inner cylinder and the lower end surface of the transport pipe for injecting driving water into the inside of the transport pipe when the upper end surface of the inner cylinder and the lower end surface of the transport pipe are opened by this movement; The upper end surface of the inner cylinder of the cover can be pressed against the lower end surface of the transport pipe to seal the two end surfaces, and when driving water is supplied into the injection cover, the two ends can be closed based on the water pressure of this driving water. An injection nozzle for a jet pump, comprising: a pressing means that allows movement of an injection cover in a direction in which surfaces are separated from each other;