JP3098864B2 - Vertical pull-out type self-priming pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical axis pull-out type self-priming pump in which the structure and arrangement of each chamber necessary for a self-priming operation are improved.

[0002]

2. Description of the Related Art In this type of self-priming pump, at the start of the first operation, a priming water is supplied in advance to perform an exhaust action, and at the next restart, the self-priming water remaining after the pump is stopped is used. Exhaust function. In this case, if the suction conditions are relatively easy, no major problems will occur.However, if the combined suction conditions, such as the volume of the suction pipe and the suction lift are too severe, are severe, the exhaust It was easy to cause a problem that the retained water during operation became overheated and became unable to self-prime.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has been made to improve the self-priming capability of a vertical shaft pull-out pump and to reduce the time required for the self-priming action at the time of starting. It is a thing.

[0004]

In order to solve the above-mentioned problems, a vertical pull-out type self-priming pump according to the present invention comprises a casing body, a casing cover for attaching and detaching the casing body from above, and a lower portion of the casing cover. A lower casing having a lower end face provided with an opening communicating with the suction chamber while forming a suction chamber between the casing and the casing main body; and an inner casing provided inside the casing cover and the lower casing. Is configured. An impeller is fixed at the tip of the drive shaft that passes through the center of the inner casing so as to be located in the lower casing,
A suction port communicating with the suction chamber through the suction passage is arranged at the top of the suction chamber, and a lower air / water separation chamber and an upper air / water separation chamber are formed inside the lower casing and the casing cover, which are partitioned by a porous partition plate. Is done. A discharge chamber communicating with the upper part of the upper water / water separation chamber through a discharge hole is formed on the outer periphery of the upper water / water separation chamber, and a discharge port is arranged at the uppermost part of the discharge chamber. A return water flow path communicating from the bottom of the separation chamber to the lower steam separation chamber and a return water flow path communicating from the bottom of the upper steam separation chamber to the suction chamber are provided.

[0005]

According to the construction of the casing as described above, the upper steam-water separation chamber having a considerable volume can be provided, and the steam-water separation action is sufficiently performed. Further, a discharge hole communicating the upper steam separation chamber and a discharge chamber provided on the outer periphery thereof is provided at an upper part of the discharge chamber, and the retained water must pass through a discharge hole at a high position. Since the water cannot be discharged into the discharge chamber and the discharge port is located at the top of the discharge chamber, the water does not easily reach the discharge port. No waste is discharged from the discharge port. In addition, return water channels provided at two locations return part of the water in the upper air / water separation chamber to the suction chamber, and return part of the water in the discharge chamber to the lower air / water separation chamber to sufficiently retain the water. The circulation of the impeller prevents idling of the impeller and promotes the self-priming action. By these comprehensive actions, while efficiently performing the steam-water separation action in the lower steam-water separation chamber and the upper steam-water separation chamber separated by the porous partition plate, the liquid held in the casing is effectively used to suck The air sucked from the pipe into the suction chamber is exhausted. Therefore, the self-priming action is performed reliably and effectively, the time required for the self-priming action at the time of startup is reduced, and the normal operation can be promptly shifted to.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pump equipped with a double mechanical seal shown in the drawings will be described below. In the drawing, 1 is a casing body, 2 is a casing cover, 3 is a lower casing, 4 is an inner casing, and the lower casing 3 has an outer diameter equal to or smaller than that of the casing cover 2 and is integrated with a lower portion of the casing cover 2. , A casing body 1, a casing cover 2, a lower casing 3, and an inner casing 4 constitute an entire casing. The main part of each of these members has a cylindrical outer shape, and the casing cover 2 and the lower casing 3 are shaped and dimensioned so as to be attached to and detached from the casing main body 1 from above, thereby forming a pull-out type. A casing is configured. 1a is a seal between the casing main body 1 and the casing cover 2, and 1b is a nozzle provided at the bottom of the casing main body 1 for priming, backwashing or draining.

5 is a casing body 1 and a lower casing 3
, A drive shaft penetrating through the center of the inner casing 4 and supported by the inner casing 4, 7 is an impeller having a back blade, and the impeller 7 is a lower casing 3.
Is fixed to the tip of the drive shaft 6 so as to be located close to the end face cover 3a. The end cover 3a is provided with a bell mouth-shaped opening 8 communicating with the bottom of the suction chamber 5, and the inner surface of the lower casing 3 is provided with a convex baffle plate 3b as shown in FIG. 7 are formed at a predetermined angle with a small gap therebetween.

[0008] The inner casing 4 includes a casing cover 2.
An upper cylindrical portion 4a located inside the cylindrical portion 2a and a lower cylindrical portion 4b located inside the lower casing 3 are provided between the upper cylindrical portion 2a and the upper edge of the back blade of the impeller 7. Is provided with a flange 4c having the same diameter as the impeller 7 while maintaining a gap of about 0.3 to 0.5 mm. 11 is an upper water / water separation chamber formed between the cylindrical portion 2a of the casing cover 2 and the upper cylindrical portion 4a of the inner casing 4, and 12 is formed between the lower casing 3 and the lower cylindrical portion 4b of the inner casing 4. Lower steam separation chamber, 13 is steam separation chamber 1
It is a perforated partition plate provided between 1 and 12.

Reference numeral 14 denotes a suction port to which a suction pipe (not shown) is connected. Reference numeral 15 denotes a suction flow path for connecting the suction port 14 to the suction chamber 5. The suction port 14 is provided at the uppermost part of the suction chamber 5. The suction channel 15 has a sectional area equal to or larger than that of the suction port 14. 16 is a discharge chamber, 16
Reference symbol a denotes a bottom plate of which the bottom plate 16a projects in a flange shape from the inner surface of the casing body 1 toward the cylindrical portion 2a of the casing cover 2, and has a substantially C-shape avoiding a portion where the suction flow path 15 is provided. It is formed and communicates with the upper steam separation chamber 11 through a plurality of discharge holes 17 provided in the upper part of the cylindrical portion 2a. Reference numeral 18 denotes a discharge port to which a discharge pipe (not shown) is connected, and is arranged at a high position so as to communicate with the upper part of the discharge chamber 16.

The upper steam separation chamber 11 and the lower steam separation chamber 12
Is communicated by a number of small-diameter holes 13a of the porous partition plate 13. Further, apart from these holes 13a, the return water flow path 2 connects the lower part of the upper steam separation chamber 11 to the suction chamber 5.
1 is formed through a perforated partition plate 13 and a lower casing 3. Further, the lower part of the discharge chamber 16 is connected to the lower steam separation chamber 1.
The return water flow path 22 communicating with the bottom plate 2 of the discharge chamber 16
6a, the cylindrical portion 2a of the casing cover 2, and the porous partition plate 13.

Reference numeral 25 denotes an external suspension pipe, reference numeral 26 denotes an internal suspension pipe, and the casing body 1 comprises an external suspension pipe 25.
The components from the casing cover 2 to the bell mouth-shaped opening 8 are unitized together with rotating members such as the drive shaft 6 and are suspended by an internal suspension tube 26.

FIG. 4 exemplifies a state of installation, in which an external suspension pipe 25 is fixed at its upper end to a floor 27 by a suitable support structure known in the art, and an internal suspension pipe 26 is attached at its upper end to a motor 28 as a motor. And attach the external suspension pipe 25
And the unit such as the casing cover 2 is integrated with the casing main body 1. When the internal suspension pipe 26 is pulled up, the casing main body 1 and the external suspension pipe 25 are fixed to the floor 27. The pull-out structure allows a unit such as the casing cover 2 to be lifted as it is.

FIG. 4 shows an example of installation in a facility for handling a liquid containing a radioactive substance. Reference numerals 101 and 102 denote radiation shielding materials inserted between a hole 27 a of a floor 27 and an external suspension pipe 25. 103 is the fixture, 104 is the mounting base on which the external suspension pipe 25 is suspended, 10
Reference numeral 5 denotes a radiation shielding material inserted between the internal suspension pipe 26 and the drive shaft 6.

Reference numeral 31 denotes a bearing, 32 denotes a mechanical seal on the atmosphere side, 33 denotes a mechanical seal on the impeller side, and the drive shaft 6 is supported by the internal suspension pipe 26 by a bearing 31 and the like, and the mechanical seals 32, 33 are used. It is sealed and forms a unit integral with the internal suspension pipe 26 and the like. 3
Reference numeral 4 denotes a flushing water supply pipe to these double mechanical seals, 35a and 35b denote water guide holes thereof, 36 denotes a flushing water discharge pipe, 37 denotes a water guide hole thereof, and flushing water is supplied from a water guide hole 38 provided in the mechanical seal 33. After entering, it rises between the guide cylinder 39 and the sleeve 40 and passes through the outer periphery of the mechanical seal 32 to the flushing water discharge pipe 36.

This embodiment is configured as described above. Next, the operation will be described. First, at the time of startup, water is injected from a priming system pipe (not shown) to fill the casing. Full water is a state in which the water level reaches the lower surface of the suction port 14 and the lower surface of the discharge port 18 as shown by a chain line L in FIG. It is. When the pump is started in this state, the water level in the suction chamber 5 drops to near the lower end of the bell mouth-shaped opening 8, and the water in the upper steam separation chamber 11 and the lower steam separation chamber 12 is discharged from the discharge port 1.
The water in the tank is started to rise into the suction pipe connected to the suction port 14 by applying a negative pressure corresponding thereto. This is the first stage of the self-priming action. If the operation is continued as it is, the process shifts to the following second stage.

That is, since the water level in the suction chamber 5 is lowered, air is also sucked in, and the impeller 7 tends to run idle, and the air / water separation chambers 11 and 12 and the discharge chamber 1
The inside of 6 is in a water-water turbid state, and bubbles rise due to the water-water displacement action, and water falls. A part of the water in the upper air / water separation chamber 11 is sucked into the suction chamber 5 through the return water passage 21 at the same time when the pump is started, and a part of the water in the discharge chamber 16 is also returned to the return water passage. Then, the air in the suction chamber 5 is gradually exhausted to the discharge port 18 by the series of water circulation, and the air in the suction chamber 5 is returned.
Negative pressure in the air continuously increases. In this way, the water level in the suction pipe continues to rise, and finally all the air in the suction pipe and the suction chamber 5 is exhausted to the discharge port 18 to complete the self-priming action, and the entire casing is filled with water. It will be in a normal water supply operation state.

As described above, the return water flow passages 21 and 22 return a part of the water to the suction chamber 5 or the lower air / water separation chamber 12, thereby preventing the impeller 7 from completely idling and circulating the retained water. Thus, the self-priming function is effectively continued, and the temperature of the retained water is made uniform by circulation to enhance the self-priming effect. In addition, the return water flow path 21 has a reverse flow when the check valve or the sluice valve is not installed in the pipe on the suction side or the discharge side, or when the pump is stopped in an open state even if it is present, the return flow is generated in the pipe. When the water falls and the water level in the pump drops and reaches the water level of the return water flow path 21, the pump serves as a vacuum breaker, so that the pump does not become empty due to the siphon phenomenon. The return water flow path 21 is provided at a height at which the water required for restart can be secured.

The return water flow path 21 causes internal leakage loss but is not large enough to affect the power of the pump shaft, so that there is substantially no problem. The return water flow path 22 does not cause internal leakage loss.

In the above-described second-stage self-priming operation, the baffle plate 3b formed on the inner surface of the lower casing 3 hinders the uniform flow of the steam-water turbid liquid that is vigorously discharged from the entire periphery of the impeller 7. At the same time as the lower air-water separation chamber 1
This prevents the swirling of the air-water turbid liquid in the tube 2 to speed up the collection of small bubbles and further promotes the rise of bubbles along the baffle plate 3b. In addition, the porous partition plate 13 that vertically divides the air-water separation chamber, the multi-injection of the air bubbles collected on the lower surface thereof from the large number of holes 13a upward at a lower water pressure causes the air bubbles in the upper air-water separation chamber 11 to be discharged. Are collected and pushed up to promote discharge from the discharge holes 17.

The discharge chamber 16 has a discharge port 18 at its uppermost part.
Is formed in such a size that an amount of retained water that does not interfere with the self-priming effect accompanied by exhaustion remains at a position lower than the lower surface of the discharge port 18. Therefore, even if the pipe on the discharge side is installed so as to descend from the discharge port 18, the water in the discharge chamber 16 is not drained at once immediately after starting the pump, and The sucking action can be performed without any trouble.

[0021]

As is apparent from the above-described embodiment, the present invention relates to the shape and structure of the casing, the suction port, the suction chamber, the vertically separated steam-water separation chamber, the discharge chamber, the discharge port, and the like. The structure and arrangement of the components have been devised, and a return water passage communicating from the bottom of the discharge chamber to the lower steam separation chamber and a return water passage communicating from the bottom of the upper steam separation chamber to the suction chamber are provided. Since the water-water separation in the casing is efficiently performed and the liquid retained in the casing is effectively used, the self-priming action at the time of starting can be completed in a short time. Therefore, the self-priming action is performed reliably and effectively, and the self-priming time required at the time of startup is reduced,
Even when the suction conditions are severe, the water holding does not overheat before the end of evacuation, and self-priming is not prevented, so that normal operation can be promptly started.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a partially broken side view illustrating an installation state of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing main body 2 Casing cover 3 Lower casing 4 Inner casing 5 Suction chamber 6 Drive shaft 7 Impeller 8 Opening 11 Upper air / water separation chamber 12 Lower air / water separation chamber 13 Porous partition plate 14 Suction port 15 Suction channel 16 Discharge Chamber 17 Discharge hole 18 Discharge port 21, 22 Return water flow path

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-117994 (JP, A) JP-A-58-210397 (JP, A) JP-A-53-43205 (JP, A) 105696 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 9/02 F04D 7/08 G21D 1/04

Claims (1)

(57) [Claims] 1. A casing body (1), a casing cover (2) for attaching and detaching to and from the casing body from above,
A lower casing (3) provided at a lower portion of the casing cover and having a suction chamber (5) formed with the casing body and having an opening (8) at the lower end face communicating with the suction chamber;
And a casing cover and an inner casing (4) provided inside the lower casing, the casing being constituted, and a tip of a drive shaft (6) penetrating the center of the inner casing is located in the lower casing. The impeller (7) is fixed as described above, and the suction passage (1) is provided at the top of the suction chamber.
5) In a vertical axis pull-out type self-priming pump provided with a suction port (14) communicating with a suction chamber through 5), a lower casing (3) and a lower part partitioned by a porous partition plate (13) inside a casing cover (2). Steam-water separation chamber (1
2) and an upper steam separation chamber (11) are formed, and a discharge chamber (16) communicating with the upper part of the upper steam separation chamber (11) through a discharge hole (17) is formed in the upper steam separation chamber (11). A discharge port (18) is arranged at the uppermost portion of the discharge chamber (16), and a return passage communicating from the bottom of the discharge chamber (16) to the lower steam separation chamber (12). Water channel (2
2) and the suction chamber (5) from the bottom of the upper steam separation chamber (11)
And a return water flow path (21) communicating with the pump.