CN201381989Y - Double inlet self-balancing multistage centrifugal pump - Google Patents

Abstract

The utility model relates to a double-inlet self-balance multiple-stage centrifugal pump, wherein the two ends of the pump are respectively used as inlets (double inlets), and are symmetrically provided with a plurality of single-stage impellers which can overlap to form a multi-stage impeller, and the middle portion of the pump is used as an outlet which is composed of double suction impellers. As the two ends of the pump are the inlets of the pump, and conveying medium does not need pressurizing by the impellers, the high-pressure end does not exist, and a balance water pipe does not need arranging, simultaneously, as the axial force generated by the impellers of the pump automatically balances, and the pressure on two ends of the double suction impeller is basically equal, a sealing device for high and low pressure regions does not need arranging, thereby avoiding the capacity loss caused by a balance water pipe and a sealing device arranged in an existing multi-stage centrifugal pump, and increasing the efficiency. And the double-inlet self-balance multiple-stage centrifugal pump is simpler than a multi-stage centrifugal pump which is composed of double suction impellers.

Description

Double inlet self-balancing multistage centrifugal pump

technical field

The utility model relates to a double-inlet self-balancing multistage centrifugal pump, which has a horizontal structure and includes two kinds of double-inlet self-balancing multistage centrifugal pumps, a segmental type and a volute type.

Background technique

Existing multi-stage centrifugal pumps mainly include D-type and DG-type multi-stage centrifugal pumps with impellers arranged in sequence from left to right or from right to left, and ZD-type self-balancing multi-stage centrifugal pumps with symmetrically arranged axial force self-balancing impellers. This type of pump is a multi-stage centrifugal pump composed of a single-suction impeller or the first stage is a double-suction impeller and the rest is a single-suction impeller, and there are also multi-stage centrifugal pumps composed of double-suction impellers. For a multi-stage centrifugal pump composed of full double-suction impellers, due to the use of double-suction impellers, when the number of impeller stages is large, the flow path between the impeller stages will be very complicated, which is not easy to realize. Generally, a multi-stage centrifugal pump composed of double-suction impellers only has 2 to 3 pumps. class. For the D-type and DG-type multi-stage centrifugal pumps with impellers arranged in sequence, the conveying medium is imported from one end to the outlet at the other end; for the ZD-type self-balancing multi-stage centrifugal pump with axial force self-balancing arranged symmetrically to the impellers, the conveying medium is conveyed from one end The inlet enters, and when it is close to the middle position, it is connected to the other end through the guide pipe and then discharged from the middle outlet; although the flow channel between the stages of the multi-stage centrifugal pump composed of double-suction impellers is very complicated, there is only one inlet and one outlet to deliver medium.

In order to ensure the effectiveness of the seal at the high pressure end of the multistage centrifugal pump with the above structure, it is often necessary to install a balance water pipe to reduce the pressure at the shaft seal at the high pressure end of the pump. The pump with symmetrically arranged impellers and the multistage centrifugal pump composed of double-suction impellers also need to install sealing devices at the high and low pressure sections of the pump to prevent a large amount of leakage of the medium. The setting of the balance water pipe and the sealing device inevitably increases the volume loss of the pump and reduces the efficiency of the pump.

Utility model content

In view of the above-mentioned deficiencies in the prior art, the purpose of this utility model is to provide a double-inlet self-balancing pump with a new structure that can completely avoid the above-mentioned two volume losses and is simpler in structure than a multi-stage centrifugal pump composed of double-suction impellers. Multistage centrifugal pump.

The technical scheme of the utility model is achieved in the following way: the double-inlet self-balancing multistage centrifugal pump includes a medium inlet and an outlet, and between the inlet and the outlet is a multistage impeller formed by superposition of several impellers. It is characterized in that: the outlet is in In the middle of the pump, the impeller corresponding to the outlet is a double-suction impeller, and the inlet is located at both ends of the pump. The multi-stage impeller between the inlet and the outlet at both ends is arranged symmetrically along the double-suction impeller corresponding to the outlet. The individual impellers that make up the multi-stage impeller are all single-suction impellers.

The double-inlet self-balancing multi-stage centrifugal pump includes a segmental double-inlet self-balancing multi-stage centrifugal pump in which both ends of the pump body structure are guide vanes and the middle outlet shell is a volute, and a double-inlet self-balancing multi-stage centrifugal pump in which the pump body structure is all volute. Balancing multistage centrifugal pumps.

In the utility model, since both ends of the pump are pump inlets, the conveying medium has not been pressurized by the impeller, and there is no need for a balance water pipe if there is no high-pressure end; at the same time, due to the symmetrical arrangement of the single-stage impellers at both ends, the double-suction impeller is arranged on the At the outlet, the axial force generated by the pump impeller is automatically balanced, and the pressure at both ends of the double-suction impeller is basically the same, so there is no need to install a sealing device in the high and low pressure area, which reduces the leakage of the pump, thereby avoiding the existing multi-stage centrifugal pump. The pump setting balances the volume loss from the water pipes and seals, increasing efficiency. Moreover, the utility model is simpler in structure than a multistage centrifugal pump composed of double-suction impellers.

Description of drawings

Figure 1 - Structural schematic diagram of the segmental double-inlet self-balancing multistage centrifugal pump of the utility model;

Figure 2 - Structural schematic diagram of the utility model volute double-inlet self-balancing multistage centrifugal pump.

The arrows in the figure indicate the flow direction of the medium.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

This dual-inlet self-balancing multi-stage centrifugal pump is a multi-stage centrifugal pump with a new structure proposed to avoid unnecessary volume loss caused by the existing multi-stage centrifugal pumps with balancing water pipes and sealing devices in high and low pressure areas. A multi-stage centrifugal pump with a new structure is proposed due to the complex structure of the multi-stage centrifugal pump housing composed of double-suction impellers. The structural feature of this double-inlet self-balancing multi-stage centrifugal pump is that the two ends are the pump inlets (double inlets) and several single-stage impellers are symmetrically arranged (the single-stage impellers at both ends are required to have the same structure and symmetry except for the direction of rotation. Arrangement), a multi-stage impeller formed by stacking several single-suction impellers, with the outlet of the pump in the middle consisting of double-suction impellers. The double-suction impeller casing in the middle of the pump needs to be designed as a volute, and the single-stage impeller casings at both ends can be designed as a guide vane type or a volute type. When the shells at both ends are designed as guide vanes, it is equivalent to running two parallel D-type pumps in series through double-suction impellers back to back; when the shells are all designed as volute, it is equivalent to multi-stage volute. The double-suction impeller forms a multistage centrifugal pump, but its structure is simpler and easier to cast and process. That is to say, it includes a segmental double-inlet self-balancing multistage centrifugal pump whose shell structure is guide vane and a volute double-inlet self-balancing multistage centrifugal pump whose shell structure is all volute. The two structures are described in detail below respectively.

Fig. 1 is a schematic diagram of the structure of the segmental double-inlet self-balancing multi-stage centrifugal pump of the present invention. The structure of the pump body is a guide vane; the middle is a double-suction impeller 6, and the casing is a volute. It can be seen from the figure that a number of single-suction impellers 2 with the same structure but different directions of rotation are symmetrically arranged at both ends of the double-suction impeller 6, and the water inlet section 1 at both ends of the pump body constitutes a segmental double-inlet self-balancing multi-stage centrifugal pump. The inlets 7 at both ends of the pump, and the volute outlet section 5 form the middle outlet 8 of the double-inlet self-balancing multistage centrifugal pump. The guide vane 3 with the same rotation direction as the single-suction impeller 2 is installed in the middle section 4 and constitutes a segmented double-inlet self-balancing multistage centrifugal pump casing with the water inlet section 1 and the volute-type water outlet section 5 at both ends. The medium conveyed by the pump enters the single-suction impeller 2 from the water inlet section 1 at both ends, enters the double-suction impeller 6 after being pressurized step by step, and finally enters the pump outlet 8 from the volute outlet section 5. Due to the symmetrical arrangement of the single-stage impellers 2 at both ends (the number of impeller stages at both ends can be increased and decreased at the same time, the number of impeller stages in the figure is only for illustration), the axial force generated by the pump impeller is automatically balanced, and because there is no balance water pipe and high and low areas The sealing device also reduces the leakage of the pump and improves the efficiency.

Figure 2 is a schematic diagram of the structure of the newly proposed volute double-inlet self-balancing multistage centrifugal pump. The structural form is that the two ends are the pump inlet 7, the middle is the pump outlet 8, and the two ends of the pump are arranged symmetrically by the single-suction impeller 2, and the middle It is a double-suction impeller 6, and the housings are all volutes. It can be seen from the figure that the pump body 9 and the pump cover 10 of the volute flow channel constitute the casing of the volute double-inlet self-balancing multistage centrifugal pump, and the two ends of the casing are respectively left with inlets 7 to form a double inlet. The middle of the body is the outlet 8 of the pump. Several single-suction impellers 2 with the same structure but different directions of rotation are symmetrically arranged at both ends of the double-suction impeller 6 . The pump conveying medium enters the single-suction impeller 2 from both ends of the pump body 9 and the pump cover 10 at the same time, enters the double-suction impeller 6 after being pressurized step by step, and finally enters the pump outlet 8 from the flow channel in the middle of the pump body 9 and the pump cover 10 . Since the conveying medium at the inlets of both ends of the pump has not been pressurized by the impeller, the pressure is relatively low, which ensures the sealing effectiveness of the shaft seal 11 there. leakage, improving efficiency. In addition, the single-stage impellers at both ends of the pump are symmetrically arranged (the number of impeller stages can be increased or decreased at the same time, the number of impeller stages in the figure is only for illustration), and the axial force generated by the pump impeller is automatically balanced.

The mark 12 in Fig. 1 and Fig. 2 is the front bearing part, 13 is the rear bearing part, 14 is the pump seat, and the mark 15 in Fig. 2 is the mechanical seal part.

The double-inlet self-balancing multistage centrifugal pump does not have balancing water pipes and high and low pressure sealing devices, which improves the efficiency of the pump unit, and the pump itself balances the axial force generated by the impeller automatically.

Although the dual-inlet self-balancing multistage centrifugal pump has two inlets, the two inlets are actually branched from one general inlet at the front end.

Claims (4)

1. Double-inlet self-balancing multi-stage centrifugal pump, including medium inlet (7) and outlet (8), between the inlet (7) and outlet (8) is a multi-stage impeller formed by overlapping impellers, which is characterized in that: The outlet (8) is in the middle of the pump, the impeller corresponding to the outlet (8) is a double-suction impeller (6), and the inlet (7) is located at both ends of the pump, between the inlet (7) and the outlet (8). The inter-stage multi-stage impellers are arranged symmetrically along the corresponding double-suction impellers (6) at the outlet. 2. The double-inlet self-balancing multi-stage centrifugal pump according to claim 1, characterized in that: the individual impellers forming the multi-stage impeller are all single-suction impellers (2). 3. The dual-inlet self-balancing multi-stage centrifugal pump according to claim 1 or 2, characterized in that: the centrifugal pump is a section in which the pump body structure at both ends is guide vanes (3), and the middle outlet shell is a volute Double-inlet self-balancing multistage centrifugal pump. 4. The dual-inlet self-balancing multi-stage centrifugal pump according to claim 1 or 2, characterized in that: the centrifugal pump is a double-inlet self-balancing multi-stage centrifugal pump whose casing is all volute type.