JPH0350316Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a pit-barrel type pump consisting of a canned motor pump housed in a pot, and in particular can effectively eliminate gas generated in the pot. This invention relates to an improvement of a pit-barrel pump equipped with an automatic gas venting mechanism.

[Conventional technology]

Generally, as a means of transferring low temperature liquefied gas,
A pot forming a liquid reservoir is provided in a part of the liquefied gas transfer system, and a canned motor pump having a pump suction port at the lower end is housed in this pot, and the liquefied gas is discharged to the outside from the upper end of the pot. A pit-barrel type pump is used.

However, in this type of pump, when the pump is stopped, liquid accumulates inside the pot, so when the liquefied gas in the pump suction piping system, including the pot, heats up due to sunlight etc., it gasifies and flows into the upper part of the pot. Furthermore, when the pump is started, this gas is sucked into the pump, causing the pump to run dry.

For this reason, in this type of pump, it is necessary to periodically remove the gas that accumulates in the upper part of the pot. It is proposed that the gases be vented periodically and forcibly.

From this point of view, conventional degassing devices for barrel tanks with a vertical pump placed in the center have been designed so that one end of the barrel tank is opened to the upper gas reservoir and the other end is opened to the pump suction port. A vent pipe is provided, a balance water guide pipe is inserted into the upper open end side of the vent pipe, and a part of the pump discharge water is introduced into the guide pipe as balance water, so that the flow inside the guide pipe is carried out downstream. An automatic gas venting device has been proposed in which an ejector action is generated in the balance water to cause gas to be sucked into a suction pump and discharged out of the barrel tank (Japanese Utility Model Publication No. 53-9519).

[The problem that the idea aims to solve]

However, the conventional automatic gas venting device requires a long gas venting pipe from the upper gas reservoir part of the barrel tank to the lower pump suction side, which not only results in a complicated equipment structure but also increases the tendency for upward movement. It is difficult to cause the gas to flow backward through a long pipe, and even if a guide pipe is installed to introduce some of the pump discharge water, there is a limit to the ejector effect resulting from this, and the pump discharge efficiency is limited. It is extremely difficult structurally to discharge gas without damaging the structure.

Furthermore, in the conventional automatic gas venting device, the gas discharged from the barrel tank is
Since the liquid is discharged to the outside together with the pump discharge liquid by the action of the suction pump, there is a drawback that gasification within the pump chamber is promoted and pump efficiency is reduced. Furthermore, in order to obtain an ejector action for degassing, an independent piping is installed on the pump discharge side to introduce a part of the pump discharge water, and by this, a part of the pump discharge water can be returned to the pump suction side. In order to obtain a sufficient ejector effect, it is necessary to increase the return amount, and as the equipment increases, the pump efficiency decreases as described above. Therefore, when the liquid handled by the pump is a low-temperature liquefied gas, it is almost impossible to remove the gas.

Therefore, the purpose of the present invention is to remove the gas stagnant at the upper end of the pot that houses the canned motor pump unit in a pit-barrel pump that transfers low-temperature liquefied gas, etc. Using the handled liquid, when discharging this liquid to the outside of the canned motor section, it is passed through the gas reservoir section with a diffuser effect, and is also passed through an external piping independent of the pump discharge piping. We provide a pit barrel type pump equipped with an automatic gas venting mechanism that allows gas in the pot to be smoothly discharged at all times without reducing pump efficiency with a simple configuration by transferring the liquid handled by the pump to a storage tank. It's about doing.

[Means to solve the problem]

In order to achieve the above object, the pit-barrel pump equipped with an automatic gas venting mechanism according to the present invention has a pump suction port 20 at the lower end and a pump discharge flow path 36 in a cylindrical shape around the outer periphery of the canned motor section 28. Canned motor pump unit 16 installed
is arranged in the fluid supply pot 10, and a discharge passage 74 is formed at the upper end of the canned motor pump unit 16, passing through the end plate 68 and communicating with the pump discharge passage 36. A tubular body 72 is provided, the upper end of the tubular body 72 and the upper end of the pot 10 are connected by a flange to close the upper part of the pot, and an exhaust port is provided at the upper end of the tubular body 72 to prevent the occurrence of air pollution inside the pot. In a pit barrel type pump configured to discharge gas, an opening 14 as an exhaust port independent of the discharge path 74 of the pipe body 72 is provided in a portion that closes the upper part of the pot 10, and a diffuser is connected to the opening 14. - A jet pump casing 90 is constructed with a jet pump casing 90 equipped with a pump casing 92, and the discharge side of the pump casing is connected in communication with a storage tank 96 for pump handling liquid via external piping, and furthermore, a canned motor is A jet fluid discharge nozzle 94 is guided out of the pump unit 16 from a discharge port 70 opened in the end plate 68 of the pump unit 16, and this nozzle is directed upward along the pipe body 72,
And the tip of this nozzle is connected to the diffuser section 9.
2, and when the canned motor pump unit 16 operates, the canned motor part 2 is pumped from the lower pump chamber 18.
A part of the pump handling liquid introduced into the pump 8 is supplied to the diffuser section 92 through the jet fluid discharge nozzle 94, and is transferred to the reservoir section 92 along with the gas staying at the upper end of the pot 10 through the external piping. It is characterized by the provision of an automatic degassing mechanism for transferring the gas to the tank 96.

[Effect]

According to the pit-barrel pump equipped with an automatic gas venting mechanism according to the present invention, a canned motor pump unit is housed in the fluid supply pot, and an end plate is inserted through the upper end of the canned motor pump unit. A pipe body forming a discharge passage communicating with the pump discharge passage is provided, the upper end of the pipe body and the upper end of the pot are connected by a flange to close the upper part of the pot, and an exhaust port is provided at the upper end of the pipe body. In the configuration for discharging the gas generated inside the pot, the exhaust port is configured as a diffuser part of the jet pump casing, and a jet fluid discharge nozzle is provided to face the diffuser part, thereby discharging the gas inside the pot. By the action of the diffuser, the gas remaining in the upper part can be efficiently discharged upwardly to the outside as an upward air current. Further, in this case, the fluid supplied to the jet fluid discharge nozzle directs the pump handling liquid introduced into the canned motor from the shortest distance, thereby smoothing the circulation of the circulating fluid inside the canned motor, Gas remaining at the upper end of the pot can be forcibly and effectively removed without reducing pump efficiency at all.

〔Example〕

Next, an embodiment of a pit-barrel pump equipped with an automatic gas venting mechanism according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 designates a cylindrical pot with a sealed bottom, and a fluid supply port 12 is provided on one upper side of the pot 10. As shown in FIG. Further, the upper end of this pot 10 is open, and this opening 14
Move the motor pump unit 1 into the pot 10.
6 is inserted and arranged. In this case, the motor pump unit 16 is suspended and fixed to the opening 14 of the pot 10, and the opening 14 is closed by the motor pump unit 16.

The motor pump unit 16 has a canned motor pump structure, and is equipped with a suction port 20 communicating with the pump chamber 18 at its lower end, and an impeller 22 equipped with an automatic thrust balance mechanism is disposed within the pump chamber 18. ing. Note that an axial flow inducer 2 extending into the suction port 20 is provided at the tip of the impeller 22.
Add 4. A thrust bearing mechanism 26 is provided adjacent to the pump chamber 18, and a canned motor section 28 is provided above the thrust bearing mechanism 26. However, a discharge port 30 is opened at the outer circumference of the pump chamber 18, and a pump casing 32 forming the discharge port 30 is extended upward, and the thrust bearing mechanism 26 is surrounded and fixed to the inner circumference of the pump casing 32. A cylindrical discharge passage 36 is formed between the casing 34 and the casing 34 . The pump casing 32 also surrounds the external motor casing 38 of the canned motor section 28, which is connected to the casing 34 that surrounds and fixes the thrust bearing mechanism 26. is extended to extend the discharge flow path 36. The canned motor section 28 has an outer motor casing 38 and an inner motor casing arranged concentrically.
A motor stator 42 is hermetically housed between the inner motor casing 40 and a motor rotor 44 having a hermetically sealed structure.
One end of the four motor rotor shafts 46 is extended to form a common shaft that serves as a support shaft for the impeller 22 disposed within the pump chamber 18. At both ends of the motor rotor 44, the motor rotor shaft 46 is supported by a lower bearing 48 and an upper bearing 50.
A lower motor rotor chamber 5 is provided at each end of the rotor 44.
2 and an upper motor rotor chamber 54. Note that an upper fluid chamber 56 is provided adjacent to the upper motor rotor chamber 54 and surrounding the upper end of the motor rotor shaft 46.

On the other hand, the thrust bearing mechanism 26 has thrust washers 60 fixedly arranged in a thrust bearing housing 62, which abut the upper and lower surfaces of the thrust bearing 58, which is rotatably supported on the motor rotor shaft 46, respectively. The casing 34 that surrounds and fixes the thrust bearing housing 62 is configured to integrally form a diffuser portion 64 in a part of the discharge passage 36 formed between the casing 34 and the pump casing 32. An opening 66 is appropriately provided in a part of the downstream side so as to be orthogonal to the discharge flow path 36 to direct a part of the pump discharge fluid to the thrust bearing housing 62.
Configure it to be installed within. Therefore, the fluid introduced into the housing 62 lubricates the thrust bearing mechanism 26 and directly lubricates the lower bearing 48 through the gap provided in the lower bearing 48 as appropriate. Let it flow inside.

In this way, the fluid introduced into the lower motor rotor chamber 52 passes between the internal motor casing 40 and the motor rotor 44, during which time the motor section is cooled. and flows into the upper motor rotor chamber 54 and then into the upper fluid chamber 56, lubricating the upper bearing 50 directly. The fluid introduced into the upper fluid chamber 56 is then transferred to the canned motor section 2.
It is led out to the outside of the pump casing 32, that is, into the pot 10, through a discharge port 70 formed in the end plate 68 of No.8.

Furthermore, the end plate of the canned motor section 28
A pipe body 72 having the same diameter as the outer diameter of the discharge passage 36 and whose upper end is closed is connected to the upper part closed by the groove 68, and the discharge passage 36 is connected to a discharge pipe formed inside the pipe body 72. It communicates with road 74. And tube body 7
A flange portion 76 is provided at the upper end of the pot 10, and the tube body 72 is flange-bonded to the upper end of the pot 10 to be disassembled and liquid-tightly connected. Pipe body 7
A discharge port 78 is provided at the center of the upper end of the pipe 2, and this discharge port 78 is connected to external piping. Further, a terminal box 80 is connected and fixed to a part of the tube body 72, and a compartment 82 is provided inside the tube body 72, and a conductive cable 84 led out from the terminal box 80 is inserted into the interior of the compartment 82. It is connected to a conductive cable 86 led out from the motor stator 42 of the canned motor section 28 via a connection terminal 88 as appropriate.

The above configuration shows the main structure of the pitted barrel pump embodying the present invention.

In the pit barrel type pump constructed in this way, in order to discharge the gas staying at the upper end of the pot 10, in the embodiment shown in FIG. A jet pump casing 90 is integrally provided at the upper end, and communicates with the pot 10 of the diffuser section 92 of the jet pump casing 90, and a jet fluid discharge nozzle 94 is provided so as to face the diffuser section 92. Arrange. The pressurized fluid introduced into the canned motor section 28 described above is used as the jet fluid guided to the jet fluid discharge nozzle 94, and the pressurized fluid is discharged into the pot 10 through the discharge port 70. The piping of the jet fluid discharge nozzle 94 is connected to the piping of the jet fluid discharge nozzle 94.

With this configuration, the gas accumulated in the upper part of the pot 10 is constantly transferred to the canned motor section 28 while the motor pump unit 16 is being driven.
A part of the pump handling liquid introduced into the pump is discharged as a pressurized fluid from the jet fluid discharge nozzle 94, and is led out to the pump discharge side, that is, external piping together with a part of the handling liquid under the action of the jet pump. can do. Therefore, this external piping is configured to communicate with the gas phase portion of the storage tank 96, which is a supply source of pump handling liquid.

[Effect of idea]

As is clear from the embodiments described above, according to the present invention, a jet pump section is provided at the upper end of the pot, and a jet fluid discharge nozzle is connected to the jet pump section from a discharge port opened in the end plate of the canned motor pump unit. This is achieved by leading out the pump and placing its tip facing the opening of the diffuser section of the jet pump section, and discharging a part of the pump handling liquid pressurized by the canned motor pump unit from the discharge nozzle. The discharged jet fluid is directed toward the upper exhaust port of the pot, so that the diffuser effect is extremely well achieved, and the gas stagnant at the upper end of the pot can be efficiently removed.

That is, in the present invention, by providing an opening as an exhaust port independent of the discharge piping of the pump body in the part that closes off the upper part of the pot, the gas accumulated in the upper part of the pot can be discharged without reducing pump efficiency. It has the advantage that it can be done. Moreover, in this case, there is a diffuser in the opening.
By configuring a jet pump casing with a water pump and connecting the discharge side of the pump casing to a storage tank for pump handling fluid via external piping, the pump can be used for cooling the canned motor and lubricating the bearings. By using a circulation system that discharges and recovers the liquid handled by the pump, gas can be efficiently and constantly smoothly discharged.

Further, the jet fluid discharge nozzle connected to the jet pump casing at the opening is led out to the outside from the discharge port opened in the end plate of the canned motor pump unit, and is directed upward along the pipe body. By directing the pipe and facing the opening of the diffuser section, the piping structure is shortened and the liquid is guided in a direction that facilitates the flow of the liquid. This makes gasification within the canned motor section easier, especially when handling low-temperature liquefied gas. At the same time, the gas accumulated in the upper part of the pot can be smoothly discharged.

Therefore, the pitted barrel pump equipped with an automatic gas venting mechanism according to the present invention not only has a simple structure and can be manufactured at low cost, but also has an automatic gas venting function when handling low-temperature liquefied gas, which has been difficult in the past. It has many excellent advantages, such as being easily achieved, easy to maintain, and being able to be applied immediately to existing pump equipment without major modification, and its practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of a pit-barrel pump equipped with an automatic gas venting mechanism according to the present invention. 10...pot, 12...fluid supply port, 14...
...Opening, 16...Motor pump unit, 18
... Pump chamber, 20 ... Suction port, 22 ... Impeller, 24 ... Inducer, 26 ... Thrust bearing mechanism, 28 ... Canned motor section, 30 ... Discharge section, 32 ... Pump casing , 34...K
Thing, 36...Discharge channel, 38...External motor casing, 40...Internal motor casing, 4
2...Motor stator, 44...Motor rotor,
46...Motor rotor shaft, 48...Lower bearing, 5
0... Upper bearing, 52... Lower motor rotor chamber,
54... Upper motor rotor chamber, 56... Upper fluid chamber, 58... Thrust bearing, 60... Thrust washer, 62... Thrust bearing housing, 64
... Diffuser section, 66 ... Opening, 68 ...
End plate, 70... Discharge port, 72... Pipe body, 74... Discharge path, 76... Flange portion, 78
...Discharge port, 80 ... Terminal box, 82 ... Drawing room, 8
4... Conductive cable, 86... Conductive cable, 8
8... Connection terminal, 90... Jet pump casing, 92... Diffuser section, 94... Jet fluid discharge nozzle, 96... Storage tank.

Claims (1)

[Scope of Claim for Utility Model Registration] A canned motor pump unit 16 is constructed which has a pump suction port 20 at its lower end and a pump discharge passage 36 arranged in a cylindrical shape around the outer periphery of a canned motor section 28. The canned motor pump unit 1 is housed and arranged in the fluid supply pot 10.
A pipe body 72 is provided at the upper end of the pot 6 to form a discharge passage 74 that passes through the end plate 68 and communicates with the pump discharge passage 36, and the upper end of the pipe body 72 and the upper end of the pot 10 are connected to each other. In a pit-barrel pump configured to connect with a flange to close the upper portion of the pot and provide an exhaust port at the upper end of the tube body 72 to discharge gas generated inside the pot, the portion that closes the upper portion of the pot 10 includes: An opening 14 is provided as an exhaust port independent of the discharge passage 74 of the pipe body 72, and a jet pump casing 90 having a diffuser section 92 is formed in this opening 14 to discharge the discharge of the pump casing. The side is connected to the storage tank 96 for the pump handling liquid via external piping, and the outlet 70 is opened to the end plate 68 of the canned motor pump unit 16 at the opening 14 to the outside of the pump unit 16. leading out the jet fluid discharge nozzle 94 and directing this nozzle upward along the tube body 72;
And the tip of this nozzle is connected to the diffuser section 9.
2, and when the canned motor pump unit 16 operates, the canned motor part 2 is pumped from the lower pump chamber 18.
A part of the pump handling liquid introduced into the pot 8 is supplied to the diffuser section 92 through the jet fluid discharge nozzle 94, and is transferred to the reservoir section 92 together with the gas staying at the upper end of the pot 10 through the external piping. A pit barrel type pump characterized by being equipped with an automatic degassing mechanism for transferring gas to a tank 96.