CN103486048A - Photovoltaic variable speed multistage centrifugal pump structure - Google Patents

Abstract

The invention discloses a variable-speed multi-stage centrifugal pump structure for photovoltaics, which relates to the technical field of centrifugal pump manufacturing. Including first-stage impeller, first-stage guide vane, secondary impeller, overrunning clutch, guide casing, last-stage impeller, last-stage guide vane, pump casing, the first-stage impeller and the second-stage impeller are fixed on the pump shaft I through a key connection, It rotates together with the pump shaft I; the final stage impeller is fixed on the pump shaft II through a key connection, and rotates together with the pump shaft II; the two sides of the overrunning clutch are respectively fixed on the pump shaft I and the pump shaft II through a key connection; When the pump shaft I exceeds the critical speed, the overrunning clutch combines the pump shaft I and the pump shaft II to rotate together; the guide casing is located between the secondary impeller and the final impeller, nested outside the overrunning clutch, and the guide casing connects the secondary impeller The discharged liquid is directed to the final impeller. The invention is mainly used in occasions where the rotation speed of the pump changes, such as a pump driven by a photovoltaic power source; the pump works with a variable load according to the rotation speed, and the pump has high operating efficiency.

Description

A variable speed multistage centrifugal pump structure for photovoltaic

technical field

The invention belongs to the technical field of centrifugal pump manufacturing, and in particular relates to a photovoltaic variable speed multistage centrifugal pump structure.

Background technique

At present, most of the photovoltaic pump load pumps are well pumps, and the diameter of the well is usually 4-6 inches. When the required head is 30-120m, the pump used must choose a multi-stage centrifugal submersible pump. Centrifugal pumps for loads in photovoltaic water pump systems are usually directly selected from existing general-purpose centrifugal pumps. However, photovoltaic systems are affected by regular changes in sunlight throughout the day, and the power generated by photovoltaic systems has its own characteristics. The flow-power and flow-head characteristics of multi-stage pump centrifugal pumps cannot match well with photovoltaic systems. For example, when the light intensity is low, the pump speed is low and cannot provide enough head to pump water. On the other hand, When the light intensity is high, the electricity generated by photovoltaics cannot be fully utilized effectively, resulting in waste.

After retrieval, the patent applications related to the present invention include: segmented multistage centrifugal pump with symmetrically arranged impellers (publication number: CN1439808A). balanced in the axial direction. However, the structure is coaxial, and the impellers of all parts are on the same shaft, without separation and speed change functions.

Photovoltaic water pump system with water pressure control function (public number: 101109387B), the invention patent uses batteries to store photovoltaic power generation energy to supply power to water pumps, and uses water pressure monitoring devices to detect and close-loop control water pressure. Valley filling" approach to improve the efficiency of photovoltaic water pumps. However, this method needs to add storage batteries and water pressure monitoring and control equipment, the system is complex and expensive, and the use of storage batteries can cause secondary pollution.

A new technology to improve the efficiency of photovoltaic water pump system (publication number: CN103075330), this patent uses two or more identical water pumps to work in parallel, when the light intensity is low, only one water pump is started to work, and when the light intensity is high Two or more water pumps can work simultaneously to improve the overall efficiency of the photovoltaic system. However, this system requires two or more pumps and supporting control equipment, which is not only more expensive than ordinary systems, but also extremely inconvenient to install in water wells.

Contents of the invention

The technical problem to be solved by the present invention is that the multistage centrifugal pump does not match the photovoltaic system, and the pump has low operating efficiency throughout the day. The solution provided by the present invention is to propose a photovoltaic variable speed pump by changing the structure of the multistage centrifugal pump. The multi-stage centrifugal pump structure makes the traditional single-shaft multi-stage pump into a separable modular multi-stage pump. Energy is used to determine the number of stages of centrifugal pump load operation, with simple structure and high operating efficiency.

The technical solution of the present invention is: a variable-speed multi-stage centrifugal pump structure for photovoltaics, including a first-stage impeller, a first-stage guide vane, a secondary impeller, an overrunning clutch, a guide casing, a final-stage impeller, a final-stage guide vane, and a pump casing , Pump shaft Ⅰ and concentric pump shaft Ⅱ.

The first-stage impeller and the secondary impeller are fixed on the pump shaft I through a key connection and rotate together with the pump shaft I; the last-stage impeller is fixed on the pump shaft II through a key connection and rotate together with the pump shaft II; the first-stage impeller, Guide vanes, secondary impellers, and final impellers are the same as general multistage centrifugal pumps. The two sides of the overrunning clutch are respectively fixed on the pump shaft I and the pump shaft II through a key connection, which is used to separate and combine the pump shaft I and the pump shaft II, that is, when the speed of the pump shaft I does not reach the critical speed of the overrunning clutch, the centrifugal force is insufficient. It cannot drive the overrunning clutch and pump shaft II to rotate together, only the pump shaft I rotates; when the speed of the pump shaft I exceeds the critical speed of the overrunning clutch, the centrifugal force is large enough to drive the overrunning clutch and the pump shaft II to rotate together; the guide casing is located between the secondary impeller and Between the final stage impellers, it is nested outside the overrunning clutch, and is used to guide the liquid discharged from the secondary impeller into the final stage impeller.

The blades of the first stage impeller, guide vane, secondary impeller and final stage impeller are the same as the blades of ordinary multistage centrifugal pumps, which are in the form of three-dimensional twisting, which is to improve the hydraulic performance of the impeller; the first stage impeller, secondary impeller and final stage impeller The structure is the same, the outlet width of the first stage impeller and the last stage impeller is 3~5mm smaller than the inlet width of the guide vane; the inlet of the diversion shell is connected with the outlet of the secondary impeller, and the inlet is in the form of three-dimensional twisted blades, which is to reduce hydraulic loss; The outlet width of the secondary impeller is 3~5mm wider than the inlet of the diversion shell; the outlet of the diversion shell is connected to the inlet of the last stage impeller, and the outlet is in the form of three-dimensional twisted blades, which is to pre-swirl the liquid and improve hydraulic performance. The outlet diameter is 2 to 3mm larger than the inlet diameter of the last stage impeller. The middle part of the diversion shell is in the form of a cylinder for collecting and diverting liquid, and the thickness of the middle wall of the diversion shell is 10-12mm.

The axial gap between the pump shaft I and the pump shaft II is 3~5mm; the overrunning clutch is nested in the diversion casing, the radial gap between the overrunning clutch and the diversion casing is 10~12mm, the overrunning clutch and the secondary impeller and The axial clearance of the diversion shell is 2-4mm.

The beneficial effects of the present invention are: the multi-stage impeller adopts a separated shaft structure, the impellers of each stage are arranged axially, the size is equivalent to that of a general multi-stage pump, and the structure is simple; the two-stage shaft can be separated and combined through an overrunning clutch, and the driven shaft can be Realize simultaneous rotation and differential rotation with the driving shaft; the inlet and outlet of the diversion shell adopt the form of three-dimensional twisted blades, which has small hydraulic loss and high pump operation efficiency.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a variable-speed multistage centrifugal pump for photovoltaic use according to the present invention.

Figure 2 is a schematic diagram of the inlet of the diversion shell.

Figure 3 is a schematic diagram of the outlet of the diversion shell.

In the figure: 1. Pump shaft Ⅰ, 2. First stage impeller, 3. First stage guide vane, 4. Secondary impeller, 5. Guide casing, 6. Overrunning clutch, 7. Pump shaft Ⅱ, 8. Pump casing, 9. Final stage impeller, 10. Final guide vane, 11. Inlet vane of diversion shell, 12. Exit vane of diversion shell.

Detailed ways

With reference to Fig. 1, the variable-speed multistage centrifugal pump structure for photovoltaics according to the present invention includes a primary impeller 2, a primary guide vane 3, a secondary impeller 4, an overrunning clutch 6, a guide casing 5, a final impeller 9, and a final impeller. The guide vane 10, the pump casing 8, the primary impeller 3 and the secondary impeller 4 are fixed on the pump shaft I1 through a key connection, and rotate together with the pump shaft I1; the last stage impeller 9 is fixed on the pump shaft II7 through a key connection, It rotates together with the pump shaft II7; the two sides of the overrunning clutch 6 are respectively fixed on the pump shaft I1 and the pump shaft II7 through key connections; when the pump shaft I1 exceeds the critical speed, the overrunning clutch 6 combines the pump shaft I1 and the pump shaft II7 to rotate together ; The guide case 5 is located between the secondary impeller 4 and the final stage impeller 9, nested outside the overrunning clutch 6, the guide case inlet 11 and the guide case outlet 12 are in the form of three-dimensional twisted blades, the middle is a cylindrical type, and the guide case The flow shell 5 guides the liquid discharged from the secondary impeller 4 into the final impeller 9 . Other structures of the variable-speed multistage pump for photovoltaic use in the present invention are the same as those of ordinary multistage centrifugal pumps, and will not be repeated here.

Referring to Fig. 2, the inlet 11 of the diversion casing is in the form of three-dimensional twisted blades, and the number of blades is 5. The inlet 11 of the diversion casing collects and guides the liquid at the outlet of the secondary impeller 4 to the middle of the diversion casing. The twisted blades can reduce the hydraulic loss of the pump.

Combined with Fig. 3, the outlet 12 of the diversion shell is in the form of three-dimensional twisted blades, and the number of blades is 5. The outlet 12 of the diversion shell pre-swirls the collected liquid and then guides it into the inlet of the final impeller 9. Pre-swirling of the twisted blades can improve the hydraulic power of the pump. performance.

The working process is as follows:

When the light intensity is weak, the electric energy provided by the photovoltaic system is small, the speed of the pump shaft I1 does not reach the critical speed of the overrunning clutch 6, and only the pump shaft I rotates. At this time, the pump only has the primary impeller 2 and the secondary impeller 4 to rotate with the pump shaft I1 , the liquid passing through the guide shell 5 is discharged through the non-rotating final stage impeller 9 and the final guide vane 10; when the light intensity is strong, the electric energy provided by the photovoltaic system is sufficient, and the speed of the pump shaft I1 reaches the critical speed of the overrunning clutch 6, and the overrunning The clutch 6 will drive the pump shaft Ⅱ7 to rotate together, and the liquid passing through the guide casing 5 will be discharged through the final guide vane after entering the final impeller 9 and doing work through the rotation of the final impeller.

Claims (6)

1. A variable-speed multi-stage centrifugal pump structure for photovoltaics, including the first-stage impeller (2), the first-stage guide vane (3), the secondary impeller (4), the overrunning clutch (6), the guide casing (5), the final The first-stage impeller (9), the last-stage guide vane (10), the pump casing (8), the first-stage impeller (2) and the second-stage impeller (4) are fixed on the pump shaft I (1) through a key connection, and are connected to the pump shaft I (1) rotate together; the final stage impeller (9) is fixed on the pump shaft II (7) through a key coupling, and rotates together with the pump shaft II (7); the overrunning clutch (6) is nested in the guide casing ( 5), the two sides of the overrunning clutch (6) are respectively fixed on the pump shaft I (1) and the pump shaft II (7) through key connection; when the pump shaft I (1) exceeds the critical speed, the overrunning clutch will drive the pump shaft I (1) Combined with the pump shaft II (7) to rotate together; the guide casing (5) is located between the secondary impeller (4) and the final impeller (9), nested outside the overrunning clutch (6), the guide casing (5) The liquid discharged from the secondary impeller (4) is introduced into the final impeller (9). 2. A variable-speed multistage centrifugal pump structure for photovoltaic use according to claim 1, characterized in that: the water inlet end of the diversion casing (5) is outside the secondary impeller (4), and the diversion casing (5) The water inlet end and the water outlet end are three-dimensionally twisted blades, and the middle part is cylindrical; the radial distance between the top of the three-dimensionally twisted blades at the water inlet end and the water outlet end of the diversion shell (5) and the pump casing (8) is 0-2 mm. 3. A variable-speed multi-stage centrifugal pump structure for photovoltaics according to claim 1, characterized in that: the radial gap between the overrunning clutch (6) and the guide casing (5) is 10-12mm, The axial clearance is 2-4mm. 4. A variable-speed multi-stage centrifugal pump structure for photovoltaics according to claim 1, characterized in that: the pump shaft I (1) and the pump shaft II (7) are connected through an overrunning clutch (6), and the pump shaft I (1) is the driving shaft, and the pump shaft II (7) is the driven shaft; the axial distance between the pump shaft I (1) and the pump shaft II (7) is 3-5 mm. 5. A variable-speed multistage centrifugal pump structure for photovoltaics according to claim 1, characterized in that: the first stage impeller, guide vane, secondary impeller and final stage impeller blades are the same as the blades of ordinary multistage centrifugal pumps, and are 3D twisted form. 6. A variable-speed multi-stage centrifugal pump structure for photovoltaic use according to claim 1, characterized in that: the inlet of the diversion shell is connected to the outlet of the secondary impeller, and the inlet is in the form of three-dimensional twisted blades.

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