JPS6215516Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a canned motor pump, and in particular, a part of the liquid handled by the pump is provided adjacent to the rear rotor chamber of the canned motor via a circulation pipe from the pump discharge pipe. This invention relates to an improvement in the circulation system for pump handling liquid, which is configured to flow sequentially through the rear bearing, the rotor-stator space, the front bearing, and the front rotor chamber by the action of an auxiliary pump, and then return to the pump discharge pipe. .

In general, in canned motor pumps that handle liquids that are relatively easy to vaporize, the circulating liquid vaporizes immediately after leaving the motor section. Since the liquid guided to the rotor chamber is easily vaporized, the liquid is not returned to the discharge side of the main pump, but the rear rotor chamber and the vapor zone of the liquid supply tank are connected via piping to allow the vaporized liquid to be transferred. However, this method requires a long piping system from the pump installation location to the liquid supply tank, which makes piping work troublesome and increases equipment costs. There is.

In this type of canned motor pump, the applicant has already established a system in which one side of the discharge pipe 18 of the main pump and the rear rotor chamber 12 of the motor section are communicated via a circulation tube 14B, as shown in FIG. , an auxiliary pump chamber 1 between the front rotor chamber 13 and the main pump chamber 1
5, the auxiliary pump chamber 15 and the discharge pipe 18 of the main pump are communicated via the circulation tube 14A, and a part of the liquid handled by the pump is distributed to the rear rotor chamber 12, the rear bearing 8, the space between the rotor and the stator, and the front section. A pump is proposed in which the flow is sequentially passed through the bearing 6 and the front rotor chamber 13 and is returned to the discharge pipe 18 of the main pump by the action of an auxiliary pump, and the patent No.
Obtained a patent as No. 782368 (Special Publication No. 49-37922).

That is, according to the pump of the patented invention, the circulation tubes 14A and 14B are respectively connected to the discharge pipe 18 of the main pump, and the liquid handled by the pump is circulated into the circulation system by the pressure increasing action of the auxiliary impeller 16, and the motor cooling and lubrication of the parts. In addition, by cooling the heat-generating parts as mentioned above, the circulating fluid whose temperature has risen will flow back to the high-pressure part (discharge port), making it difficult to evaporate, and effectively preventing gasification of the circulating fluid. Ru.

However, in the pump of the aforementioned patented invention, the front bearing FB and the rear bearing
Although prevention of gasification of the circulating liquid in the RB is achieved, according to the configuration of this type of conventional pump, the liquid circulating within the pump system has a pressure distribution as shown in Figure 1 with respect to its vapor pressure characteristics. state. That is, in FIG. 1, the pressure of the circulating fluid is distributed on the liquid phase side with respect to the vapor pressure characteristic curve V, and the pressure of the circulating fluid is distributed on the liquid phase side with respect to the vapor pressure characteristic curve V.
The pump suction pressure is set on curve V for convenience, but the suction pressure during actual pump operation is located on the liquid phase side) → Pump discharge port B → Circulation tube C (In this case, there is actually some pressure inside the tube) (There is a pressure drop) → Rear rotor chamber D → Front rotor chamber E → Auxiliary pump chamber F (In this case, the pressure inside the chamber is actually slightly higher than the main pump discharge pressure) → Pump discharge port B and pressure change However, as a result, the front bearing FB in the front rotor chamber E is placed in an environment with a relatively low pressure level and is easily exposed to dry conditions. In this case, the detailed pressure distribution corresponding to the position of each component in the liquid circulation system is shown in Figure 6 (in this case, the horizontal axis in Figure 6 is as shown in Figure 5). axial distances for pump configurations shown).

Therefore, as a result of various studies to overcome all the problems of conventional canned motor pumps mentioned above, the inventor of the present invention has developed an efficient way to take out a part of the liquid handled by the pump from the discharge side of the pump part to the auxiliary pump chamber. By increasing the pressure of this liquid to an appropriate pressure using an auxiliary impeller, and flowing this pressurized liquid into the canned motor in a fixed direction without any special flow path design,
We have succeeded in developing a canned motor pump that allows smooth circulation of pump fluid, provides proper lubrication of front and rear bearings, and reliably prevents cavitation.

In other words, a canned motor pump is constructed by connecting the pump section and the motor section via an adapter.
An auxiliary pump chamber is provided at the rear end of the rear rotor chamber of the motor section, and a handling liquid circulation pipe led out from a part of the discharge pipe of the pump section is communicated with this auxiliary pump chamber. An auxiliary impeller that sends liquid to the front rotor chamber is arranged, and this auxiliary impeller is attached to the motor rotor shaft.On the other hand, the adapter is provided with a liquid passage that communicates with the front rotor chamber, and this liquid passage is connected to the front rotor chamber through external piping. By communicating with a part of the discharge pipe of the pump section and properly setting the pressure of the liquid handled by the auxiliary impeller, the front rotor chamber is always maintained at a pressure higher than the discharge pressure of the pump section and is not exposed to steam. Easy front bearing ensures stable lubrication.

In addition, the shaft through hole of the motor rotor shaft that passes through the pump part and the adapter is sealed with a seal ring to prevent leakage of circulating fluid and facilitate the handling of fluids with high vapor pressure. .
Furthermore, it is possible to install an auxiliary impeller with the basic configuration of a general canned motor pump, and the circulation system for the pump handling liquid formed inside the canned motor does not become complicated, so it is possible to It has sufficient conditions for practical use, such as being extremely easy to design the flow path.

Therefore, the purpose of the present invention is to provide a canned motor pump that handles liquids that easily vaporize, such as liquefied gas, by increasing the pressure of the pumped liquid into the canned motor under pressure conditions that do not vaporize it, thereby ensuring smooth and appropriate flow. The object of the present invention is to provide a canned motor pump that maintains circulation flow, has a simple flow path design, and is easy to operate.

In order to achieve the above object, the present invention consists of a pump section and a canned motor section, and an auxiliary pump chamber is provided in the motor rotor chamber, and a part of the handled liquid is introduced into the motor rotor chamber from the discharge side of the pump section. In a canned motor pump that handles a liquid that is easily vaporized, the auxiliary pump chamber is circulated through the pump section under the action of an auxiliary impeller provided in the auxiliary pump chamber. The inlet side of this auxiliary pump chamber and a part of the discharge pipe of the pump section are communicated and connected by a circulation pipe, and a rear bearing and Rotor
Compensates for the pressure drop of the handled liquid in the motor rotor chamber between the stators and the front rotor chamber, and guides the handled liquid to the discharge side of the pump section through the liquid passage at a pressure approximately equal to the pump discharge pressure. It is characterized by being provided with an auxiliary impeller for boosting the pressure set to a certain pressure.

In the canned motor pump described above, it is preferable that the pump section and the motor section are connected via an adapter, and that the adapter is provided with a liquid passage communicating with the discharge side of the pump section.

Next, embodiments of the canned motor pump according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a pump section;
Reference numeral 2 indicates a canned motor section, and the pump section 10 and the motor section 12 are connected by an adapter 14 so as to be compatible with each other.

The pump section 10 includes a suction pipe section 20 and a discharge pipe section 2 that communicate with a pump chamber 18 in which an impeller 16 is provided.
2, and the impeller 16 is attached to the extended end of the rotor shaft 24 of the motor section 12. On the other hand, the motor section 12 includes a stator assembly 26 and a rotor assembly 28. The rotor shaft 24 is supported by a front bearing 30 and a rear bearing 32, respectively. A rotor chamber 36 is formed. However, an auxiliary pump chamber 38 is defined at the rear end of the rear rotor chamber 36, and an auxiliary impeller 40 is disposed within this auxiliary pump chamber 38 and is fixed to the rotor shaft 24. Therefore, in this auxiliary pump chamber 38,
A circulation pipe 42 led out from the discharge pipe part 22 of the pump part 10 is communicated with the pump part 10 to guide a part of the handled liquid to the rotor chamber. In this case, a through hole 46 is bored in a part of the bearing support member 44 that defines the rear rotor chamber 36 and the auxiliary pump chamber 38.
The handling liquid is introduced into the rear rotor chamber 36 through the rotor, a part of which is used for lubricating the rear bearing 32, and the remainder is transferred to the front rotor chamber 34 via the rotor-stator.

Additionally, the adapter 14 includes a front rotor chamber 36
and a fluid passage 48 that communicates with the discharge side of the pump portion 10.
That is, the fluid passage 48 is formed by drilling a through hole 52 in a part of a bearing support member 50 that supports the front bearing 30, and communicates with the front rotor chamber 34, and is also connected to an external conduit 5 from one side of the adapter 14.
4 is led out to the discharge pipe portion 22 of the pump portion 10.
Alternatively, an external conduit 54
Alternatively, the fluid passage 48 of the adapter 14 may be directly connected to the discharge side of the pump section 10 without providing a through hole 49 shown by a broken line in the adapter 14 (for example, it is preferable to drill a through hole 49 shown by a broken line in the adapter 14). Note that a seal ring 58 is provided to seal a shaft through hole 56 of the rotor shaft 24 that passes through the adapter 14 and the pump chamber 18, so that the circulating fluid in the fluid passage 48 does not flow to the impeller 16.
It is constructed so that it does not leak into the

According to the canned motor pump according to the present invention configured as described above, a part of the handled liquid discharged from the pump section 10 is introduced into the auxiliary pump chamber 38 via the circulation pipe 42, and the auxiliary impeller 40 is guided into the rear rotor chamber 36 through the through hole 46. A part of the handling liquid introduced into the rear rotor chamber 36 lubricates the rear bearing 32 and circulates into the auxiliary impeller 40, while the remaining part passes through the gap between the stator 26 and the rotor 28 to cool the motor section 12. , and then guided to the front rotor chamber 34. A part of the handling liquid introduced into the front rotor chamber 34 lubricates the front bearing 30 and is guided to the liquid passage 48 of the adapter 14, and the remainder passes through the through hole 52 to the liquid passage 48. They are guided, merged, and further circulated through the external conduit 54 to the discharge side of the pump section. Therefore, according to the present invention, the circulation pipe 42 communicating with the suction port side of the auxiliary pump chamber 38 is
Since it communicates with a portion of the pump section 10 that has relatively high hydraulic pressure, vaporization of the liquid within the circulation pipe 42 is prevented, and the liquid is further pressurized by the auxiliary impeller 40 . As a result, gasification of the liquid flowing through the liquid passageway 48 in the canned motor section 12 and the adapter 14 is prevented, and the cooling and lubrication efficiency in the motor section 12 can be improved.

The characteristics of the canned motor pump according to the present invention described above will become clearer from the pressure distribution characteristic curve of the circulating fluid shown in FIG.

That is, in FIG. 3, the suction pressure A of the pump section 10 increases to the discharge pressure B at the discharge pipe section 22, and the circulating fluid at this discharge pressure B is supplied to the auxiliary pump chamber 38 via the circulation pipe 42, The pressure is increased by the impeller 40 to a discharge pressure C, which is then introduced into the rear rotor chamber 36. Therefore, a portion of the circulating fluid in the rear rotor chamber 36 lubricates the rear bearing 32 and flows back to the inlet of the auxiliary impeller 40 (shaded area). In addition, the liquid passage 48 passes through the front rotor chamber 34.
The circulating fluid guided to the pump part 10 decreases in pressure while increasing in temperature, lubricates the front bearing 30 (shaded area), decreases to the discharge pressure B of the pump part 10, and is circulated to the discharge pipe part 22. Therefore, as is clear from FIG. 3, the pressure distribution of the circulating fluid exists in the liquid phase part that is sufficiently separated from the gas phase part, so the canned motor pump according to the present invention is suitable for handling liquids that easily vaporize. Suitable for this purpose, it is possible to supply liquid from the pump section to the auxiliary pump chamber placed to circulate liquid inside the canned motor under suitable pressure conditions without vaporization, making it extremely versatile. .

On the other hand, the pressure distribution characteristics in the circulation system of the handled liquid in the canned motor pump according to the present invention are shown in FIG. 4 in comparison with the structure of the canned motor pump shown in FIG. 2. (In this case, the horizontal axis in FIG. 4 indicates the axial distance of the pump configuration shown in FIG. 2). That is, according to the present invention, compared to the structure and characteristics of the conventional canned motor pump shown in FIG. 5 and FIG. A part of the liquid is guided through the circulation pipe 42 to the auxiliary impeller 40 (,), and the auxiliary impeller further increases the pressure and supplies it into the motor rotor chamber, and the handled liquid is maintained at a higher pressure than the pump discharge pressure (). It can be easily understood that the fluid can be smoothly circulated to the discharge pipe section 22 ().

Therefore, the canned motor pump according to the present invention is configured so that a part of the pump handling liquid that flows into the canned motor always flows in a fixed direction when handling liquid that easily vaporizes. There is no need to design a special flow path, and it is possible to effectively increase the pressure of the liquid, lubricate the bearings, and cool the motor section. In addition, in the present invention, since the motor section and the pump section are connected via an adapter, a part of the circulation system for pump handling liquid in the motor section can be easily configured using this adapter. In addition, it has many excellent advantages suitable for practical use, such as being able to easily adjust liquid leakage to the suction side of the pump section.

The preferred embodiments of the present invention have been described above, but within the scope of the spirit of the present invention,
Of course, various design changes can be made.

[Brief explanation of the drawing]

Fig. 1 is a pressure distribution characteristic curve of circulating fluid in a conventional canned motor pump, Fig. 2 is a cross-sectional side view of essential parts showing an embodiment of the canned motor pump according to the present invention, and Fig. The pressure distribution characteristic curve of the circulating fluid in the canned motor pump shown in the figure,
Fig. 4 is a pressure distribution characteristic curve diagram in the circulation system of the handled liquid of the canned motor pump shown in Fig. 2, Fig. 5 is a sectional side view of the main part of the conventional canned motor pump, and Fig. 6 is a sectional side view of the main part of the conventional canned motor pump. It is a pressure distribution characteristic curve diagram in the circulation system of the liquid handled by the canned motor pump shown in the figure. 10... Pump section, 12... Canned motor section, 14... Adapter, 16... Impeller, 18
... Pump chamber, 20 ... Suction pipe section, 22 ... Discharge pipe section, 24 ... Rotor shaft, 26 ... Stator assembly, 28 ... Rotor assembly, 30 ... Front bearing, 32 ... Rear bearing, 34... Front rotor chamber, 36... Rear rotor chamber, 38... Auxiliary pump chamber, 40... Auxiliary impeller, 42... Circulation pipe,
44...Bearing support member, 46...Through hole, 4
8...Liquid passage, 50...Bearing support member, 5
2...Through hole, 54...External conduit, 56...Shaft through hole, 58...Seal ring.

Claims (1)

[Scope of claim for utility model registration] a. Consisting of a pump part and a canned motor part, with an auxiliary pump room attached to the motor rotor room,
In a canned motor pump that handles liquid that is easily vaporized, a part of the handled liquid is introduced into the motor rotor chamber from the discharge side of the pump section and circulated to the pump section under the action of an auxiliary impeller provided in the auxiliary pump chamber, b. An auxiliary pump chamber that communicates with the rear rotor chamber is provided on the rear surface of the rear bearing of the canned motor section, c. The inlet side of this auxiliary pump chamber and a part of the discharge pipe of the pump section are connected via a circulation pipe, and d. The system compensates for the pressure drop of the handling liquid in the circulation pipe in the pump chamber, and also compensates for the pressure drop of the handling liquid in the motor rotor chamber through the rear bearing and the rotor-stator to the front rotor chamber, thereby reducing the handling liquid. A canned motor pump that is provided with an auxiliary impeller for boosting the pressure, which is set to lead the liquid to the discharge side of the pump section through a passageway at a pressure substantially equal to the pump discharge pressure.