CN102840142A - Multistage shield pump placed on electric motor - Google Patents

Abstract

The invention relates to a multi-stage canned pump with an upper motor. The motor part is arranged on the upper part of the canned pump, the pump part is arranged on the bottom of the canned pump, and an intermediate connecting section is arranged between them. This structural design is very beneficial to the installation and maintenance of the canned pump set; there is a thrust bearing between the pump part and the intermediate connection section. The lower end surface of the thrust bearing is connected to the high-pressure water chamber of the pump part, and the upper end surface is connected to the low-pressure water chamber surrounded by the middle connecting section, thus forming an axial water thrust pointing to the upper part of the canned pump, which can balance the canned pump group The gravity of the shafting reduces the load on the thrust bearing to near zero. The motor rotor and the stator are respectively sealed by the rotor shielding sleeve and the stator shielding sleeve, and a gap is left between the two shielding sleeves. A small amount of liquid passing through the thrust bearing passes through the gaps of each bearing and shielding sleeve in turn to lubricate the bearing and cool the motor. The structure guarantees no leakage and smooth fluid delivery, which improves the durability of the pump.

Description

A kind of multi-stage canned pump with motor on top

technical field

The invention relates to a canned pump, in particular to a multi-stage canned pump with two pump shafts, an upper-mounted motor, and a small axial force. The invention can be widely used in various water conveying systems in municipal, petrochemical and other fields.

Background technique

In order to meet the high head requirements of the water delivery system, multistage centrifugal pumps are usually used as power equipment. However, ordinary multistage centrifugal pumps usually use packing seals or mechanical seals, and there is a certain amount of liquid leakage. Especially when the operation deviates from the optimal working condition, the noise and vibration are large, the load on the bearing is large, and the operation reliability of the pump is deteriorated. Like this, not only influence people's working and living environment, also bring certain potential safety hazard. In some occasions, canned pumps are also used as water delivery equipment. The existing canned pump technology generally needs to set up a special water circulation channel for cooling the motor and lubricating the bearing. Some canned pumps use the method of taking high-pressure water from the pump outlet pipe and discharging circulating water from the shaft center hole to the impeller suction port. The disadvantage of this method is that it is difficult to process the center hole of the shaft, and the circulating water is likely to interfere with the water flow at the inlet of the impeller. Due to the gravity of the shafting parts of the canned pump and the axial water thrust acting on the impeller, the bearing load is large and the bearing is easy to wear, thereby reducing the operating safety and durability of the pump. In recent years, canned pump design techniques have continued to evolve. For example, the invention patent ZL200910135730.1 adopts the design concept of double shielding hoses, which can greatly reduce the operating noise of the unit, but the structural design of the flow-passing parts is relatively complicated, and the flow loss of the pump is relatively large. Overall, the current canned pump technology still needs to be improved. Especially when multi-stage canned pumps are used in high-rise water supply systems or central air-conditioning systems, the existing multi-stage centrifugal pump and canned pump technologies are difficult to meet the requirements in terms of bearing durability and pump operation stability. In order to optimize the hydraulic design of the multi-stage canned pump, improve the structure of the pump, and further reduce the axial water thrust on the pump, it is necessary to design a new multi-stage canned pump structure. This structure can make the canned pump have a high delivery head, bearing It has the characteristics of low axial load and no fluid leakage, so as to effectively meet the requirements of various water delivery systems for electromechanical equipment.

Contents of the invention

The purpose of the present invention is to propose a multi-stage canned pump with an upper motor. This structure can make the canned pump have the characteristics of high delivery head and low axial load of the bearing, so as to ensure the durability of the bearing and improve the operation reliability of the pump. .

Technical scheme of the present invention is as follows:

A multi-stage shielded pump with an upper motor, comprising a pump inlet pipe, a pump suction inlet, a pump inlet, a pump outlet, a pump outlet pipe, a primary impeller, a primary space guide vane, a secondary impeller, a secondary space guide vane, Pump section casing, pump end connection section, water outlet channel, intermediate connection section, thrust plate, upper end bearing, motor shaft, middle end bearing, high pressure water chamber, low pressure water chamber, auxiliary bearing, pump shaft, bearing seat, motor rotor , Stator, motor section casing, circulating water chamber, rotor shielding sleeve, stator shielding sleeve. The pump suction inlet, first-stage impeller, first-stage space guide vane, secondary impeller, secondary space guide vane, water outlet channel and pump section casing form the pump part (pump section) of the canned pump. The motor rotor, stator, motor section casing and motor shaft form a motor part (motor section). The thrust plate and the bearing seat constitute the thrust bearing of the shielded pump, which is characterized in that: the thrust bearing is installed on the pump end connection section, its lower end surface is connected with the high-pressure water chamber, and its upper end surface is surrounded by the middle connection section. The low-pressure water chambers are connected.

Another technical feature of the present invention is that: the pump part is located at the lower part of the multi-stage canned pump, and the motor part is located at the upper part of the multi-stage canned pump, and they are separated by an intermediate connecting section to become independent structural units .

The technical feature of the present invention is that the motor shaft is supported by the upper end bearing and the middle end bearing, and the pump shaft is supported by the thrust bearing and the auxiliary bearing. The motor shaft and the pump shaft are connected through a coupling device arranged in the middle coupling section.

The motor rotor is completely wrapped by the rotor shielding sleeve and fixed on the motor shaft. The motor stator is completely wrapped by the stator shielding sleeve and fixed in the motor segment casing. The motor rotor, stator, rotor shielding sleeve, and stator shielding sleeve are arranged coaxially with the motor shaft, and a radial gap of preferably 0.15-0.5mm is left between the rotor shielding sleeve and the stator shielding sleeve.

The pump inlet pipe and the pump outlet pipe are located on the same axis.

Compared with the prior art, the present invention has the following advantages and technical effects: ①The lower part of the thrust bearing is a high-pressure water chamber, and the upper part is a low-pressure water chamber. When the pump is running normally, the high-pressure water chamber will be filled with high-pressure liquid from the pressurized impeller of the last stage of the canned pump. The pressure acts directly under the thrust plate; while in the low-pressure water chamber, only the liquid leaking from the pump part to the intermediate coupling section has a pressure much lower than that of the liquid in the high-pressure water chamber. The resultant axial force acting on the thrust disc is upward, which can offset most of the gravity of the shafting of the shielded pump group (including the motor and the pump), so that the load on the thrust bearing is greatly reduced. Thereby prolonging the service life of the thrust bearing. ②Because the pump part and the motor part are separated by the middle connecting section, they become independent structural units. In this way, the overall structure of the canned pump set is very simple, which makes installation and maintenance very convenient. ③For shielded pump sets, the motor shaft is supported by the upper end bearing and the middle end bearing, and the pump shaft is supported by the thrust bearing and auxiliary bearing. They are connected through a coupling device arranged in the middle coupling section. In this way, the installation difficulty of the unit is greatly reduced, and the processing requirements for shaft parts are also reduced. ④The pump inlet pipe and the pump outlet pipe are located on the same axis. This is suitable for the pipeline layout of many operating sites.

Description of drawings

Fig. 1 is a main sectional view of a multi-stage canned pump with an upper motor provided by the present invention.

Fig. 2 is a sectional view of section A-A in Fig. 1 .

In the figure: 1-pump inlet pipe; 2-pump inlet; 3-pump section casing; 4-water outlet channel; 5-pump end connection section; 6-thrust plate; 7-middle connection section; 8-motor section casing; -stator; 10-upper bearing; 11-circulating water pipe; 12-circulating water chamber; 13-rotor shielding sleeve; 14-motor rotor; 15-motor shaft; 16-middle end bearing; 17-high pressure water chamber; 18 -Secondary space guide vane; 19-Secondary impeller; 20-First stage space guide vane; 21-First stage impeller; 22-Pump suction inlet; 23-Pump outlet pipe; 24-Pump outlet; 25-Pump base; 26 -Stator shielding sleeve; 27-auxiliary bearing; 28-pump shaft; 29-bearing seat; 30-low pressure water chamber.

Detailed ways

The principle and structure of the present invention will be further described below in conjunction with the accompanying drawings.

Example

As shown in Figures 1-2, Figure 1 is a main sectional view of a multi-stage canned pump with an upper motor provided by the present invention, including a pump inlet pipe 1, a pump inlet 2, a pump suction inlet 22, a first stage impeller 21, a first stage Primary space guide vane 20, secondary impeller 19, secondary space guide vane 18, high pressure water chamber 17, water outlet channel 4, pump section casing 3, pump end coupling section 5, pump shaft 28, pump outlet pipe 23, motor rotor 14, motor shaft 15, stator 9, motor section housing 8. Among them, the pump suction port 22, the primary impeller 21, the primary space guide vane 20, the secondary impeller 19, the secondary space guide vane 18, the high-pressure water chamber 17, the water outlet channel 4, the pump section casing 3 and the pump end connection section 5 The pump part that constitutes the canned pump is the pump section. In this pump section, the pump suction port 22, the primary impeller 21, the primary space guide vane 20, the secondary impeller 19, and the secondary space guide vane 18 are sequentially arranged from bottom to top to form a pump. The main body of the pump section is provided with a pump end coupling section 5 on the top of the pump section main body, and a high-pressure water chamber 17 is formed between guide vanes 18 in the secondary space of the pump end coupling section 5. The main body of the pump section is wrapped in the pump section casing 3, and 3 and the main body of the pump section are provided with a water outlet channel 4; the motor rotor 14, the motor shaft 15, the stator 9 and the motor section casing 8 form the motor part, that is, the motor section.

An intermediate coupling section 7 is provided between the pump part and the motor part, so that the structural units of the canned pump are relatively independent.

The motor rotor 14 is sealed and fixed on the motor shaft 15 by the rotor shielding sleeve 13; a stator 9 is arranged radially outside the motor rotor 14, and a stator shielding sleeve 26 and a motor segment casing 8 are respectively provided on the inner side and the outer side of the motor rotor 14. In this way, there is a gap flow passage between the stator shielding sleeve 26 and the rotor shielding sleeve 13, which communicates with the space where the bearings on both sides of the motor rotor are located, that is, it indirectly communicates with the low pressure water chamber 30 and the circulating water chamber 12.

On both sides of the motor rotor 14, an upper end bearing 10 and a middle end bearing 16 are arranged axially; The motor shaft 15 and the pump shaft 28 are coupled by a coupling device arranged in the middle coupling section 7 .

The pump inlet pipe 1 and the pump outlet pipe 23 are arranged on the same axis. A circulating water pipe 11 is provided between the circulating water chamber 12 and the pump inlet pipe 1 .

The working process of the pump is as follows:

The fluid from the pump inlet 2 enters the first-stage impeller 21 through the pump inlet 22 , and the fluid flows into the first-stage space guide vane 20 after being pressurized. Afterwards, the fluid enters the secondary impeller 19 and the guide vane 18 in the secondary space, and reaches the high-pressure water chamber 17 . Except for a small amount of fluid leaking to the intermediate coupling section 7 through the thrust bearing, most of the fluid will flow to the pump outlet 24 through the outlet channel 4 .

Since the upper and lower ends of the thrust bearing of the canned pump are respectively a low-pressure water chamber 30 and a high-pressure water chamber 17, a pressure difference between the two ends of the thrust plate 6 is formed. Under the strong pressure difference, a small amount of liquid in the high-pressure water chamber 17 leaks to the low-pressure water chamber 30 to lubricate the thrust bearing. Since there is a large pressure difference between the upper and lower ends of the thrust plate, the formed axial force can basically offset the gravity of the shafting of the shielded pump unit, thereby reducing the load on the thrust bearing and reducing the wear of the bearing. The liquid in the middle connecting section 7 will further flow along the axial direction, successively pass through the middle end bearing 16 , the gap between the motor rotor shielding sleeve and the stator shielding sleeve, and the upper end bearing 10 to reach the circulating water chamber 12 . During the movement, this part of the liquid, on the one hand, plays the role of lubricating the bearing, and on the other hand, it also takes away the heat generated by the motor when the canned pump is working. As long as the flow control of this part of the liquid is appropriate, it can provide a very good operating environment for the canned pump group.

The liquid in the circulating water chamber 12 flows to the pump inlet pipe 1 through the circulating water pipe 11 and returns to the pump inlet 2 under the residual pressure of the fluid.

Therefore, the design of the canned pump can fully guarantee the operation without liquid leakage.

For the pump part (section), the first-stage impeller and the first-stage space guide vane form a stage unit. Afterwards, each stage unit consists of an impeller and a space guide vane. Each level unit is preferably designed to have the same structure. According to the operating head requirements of the canned pump, more stage units can be used.

The pump base 25 is installed at the bottom of the canned pump. On the one hand, as a hydraulic component, it is the pump suction chamber;

Since the intermediate coupling section 7 is provided between the pump part and the motor part, the structural units of the canned pump are relatively independent. Moreover, since the motor shaft 15 and the pump shaft 28 are respectively supported by different bearing sets, the installation difficulty of the shaft system and the machining accuracy requirements of related parts can be greatly reduced. Such a structural design is also very beneficial for the maintenance of the canned pump.

The pump inlet pipe 1 and the pump outlet pipe 23 are arranged on the same axis. This arrangement is suitable for the pipeline arrangement of many canned pumps in practical applications.

Claims (5)

1. the multi-stage shield pump of putting on the motor contains pumping intake piping (1), pump inlet (2), Pump Suction Nozzle (22), first stage impeller (21); Chopped-off head spatial guide blade (20), secondary impeller (19), secondary spatial guide blade (18), pump section shell (3), pump end connecting section (5); Exhalant canal (4), pump discharge (24), pump discharge pipe (23), thrust disc (6), middle connecting section (7); Upper end bearing (10), motor shaft (15), middle step bearing (16), high pressure water chamber (17), low-pressure water chamber (30); Auxiliary bearing (27), pump shaft (28), bearing support (29), rotor (14), stator (9); Motor section shell (8), circulating water chamber (12), Rotor can (13), stator can (26), described Pump Suction Nozzle (22); First stage impeller (21), chopped-off head spatial guide blade (20), secondary impeller (19), secondary spatial guide blade (18), exhalant canal (4); Pump shaft (28) and pump section shell (3) are formed the pump section of canned motorpump, described rotor (14), and stator (9), motor section shell (8) and motor shaft (15) are formed motor section; Described thrust disc (6) and bearing support (29) are formed the thrust-bearing of canned motorpump, and it is characterized in that: thrust-bearing is installed on the pump end connecting section (5), and its lower end surface and high pressure water chamber (17) join, and the low-pressure water chamber (30) that its upper-end surface and middle connecting section (7) surround joins.

2. according to the multi-stage shield pump of putting on the described motor of claim 1; It is characterized in that: described pump section is positioned at the bottom of multi-stage shield pump; Described motor section is positioned at the top of multi-stage shield pump, and they are separated by middle connecting section (7), become element of construction independent of each other.

3. according to the multi-stage shield pump of putting on claim 1 or the 2 described motors, it is characterized in that: described motor shaft (15) is supported by upper end bearing (10) and middle step bearing (16), and pump shaft (28) is supported by thrust-bearing and auxiliary bearing (27); Motor shaft (15) and pump shaft (28) connect through the hitch bar in the connecting section (7) in the middle of being arranged on.

4. according to the multi-stage shield pump of putting on claim 1 or the 2 described motors, it is characterized in that: described rotor (14) is wrapped up by Rotor can (13) fully, and is fixed on the motor shaft (15); The stator of motor (9) is wrapped up by stator can (26) fully, and is fixed in the motor section shell (8); Rotor (14), stator (9), Rotor can (13), stator can (26) all with motor shaft (15) coaxial arrangement, and leave the radial clearance of 0.15～0.5mm between Rotor can (13) and the stator can (26).

5. according to the multi-stage shield pump of putting on the described motor of claim 1, it is characterized in that: described pumping intake piping (1) is positioned on the same axis with pump discharge pipe (23).

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