A fire pump for improving the hump phenomenon of small flow

Abstract

The invention discloses a fire pump for improving the small flow hump phenomenon, which comprises a volute, an impeller, and a rotating shaft. The volute comprises a front side wall, an inlet pipe, and a pressure water chamber. The impeller comprises a front cover plate, a rear cover plate, blades, and an inlet ring. The invention is characterized in that an adjustment ring is arranged on the outer circumference of the inlet ring, and the adjustment ring is rotatably arranged relative to the inlet ring. The adjustment ring comprises a ring body, a first guide blade, and a first connecting hole. The outer circumference of the ring body is arranged with a first guide blade, and a plurality of first guide blades are evenly distributed along the circumferential direction. The left end face of the inlet ring is connected with an end cover ring through a connecting piece. A second connecting hole is provided on the inlet ring, and the second connecting hole is arranged on the right side of the adjusting ring. The invention can improve the regulating effect of the unsteady flow and pressure pulsation at the inlet of the fire pump, can reduce the cavitation performance and the inlet secondary flow, thereby improving or eliminating the small flow hump phenomenon, and improving the hydraulic performance and operation stability of the fire pump.

Description

Technical Field

[0001] The invention relates to the technical field of fire pumps, and in particular to a fire pump capable of improving a small flow hump phenomenon. Background Art

[0002] like Figure 1 As shown, the existing fire pump includes a volute, a centrifugal impeller, and a rotating shaft. The impeller is rotatably installed in the volute, the impeller is installed on the rotating shaft, the rotating shaft is connected to the motor transmission, the volute includes a front side wall, an inlet pipe, and a pressure water chamber, the inlet pipe and the pressure water chamber are respectively connected to the upstream and downstream of the front side wall, the impeller includes a front cover plate, a rear cover plate, blades, and an inlet ring, a plurality of blades are evenly distributed along the circumference and connected between the front cover plate and the rear cover plate, the inlet end of the front cover plate is provided with an inlet ring, the inlet ring is matched with the recessed part of the inlet pipe; the outer peripheral surface of the inlet ring is provided with a guide vane, and the guide vane is fixed relative to the inlet ring. However, the existing fire pump still has the problems of large unsteady flow at the inlet of the fire pump, large influence on cavitation performance and inlet secondary flow, and hump phenomenon that affects the hydraulic performance and operation stability of the fire pump. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a fire pump that improves the small flow hump phenomenon. Through the optimized design of the adjustment ring, the second guide vane, the second connecting hole, the third guide vane and / or the third connecting hole, the regulation effect of the unsteady flow and pressure pulsation at the inlet of the fire pump can be improved, the cavitation performance and the inlet secondary flow can be reduced, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A fire pump for improving the hump phenomenon of small flow rate, comprising a volute, a centrifugal impeller, and a rotating shaft, wherein the impeller is rotatably mounted in the volute, the impeller is mounted on the rotating shaft, the rotating shaft is connected to the motor in a transmission manner, the volute comprises a front side wall, an inlet pipe, and a pressure water chamber, the inlet pipe and the pressure water chamber are respectively connected to the upstream and downstream of the front side wall, the impeller comprises a front cover plate, a rear cover plate, blades, and an inlet ring, a plurality of blades are evenly distributed along the circumferential direction and connected between the front cover plate and the rear cover plate, an inlet ring is arranged at the inlet end of the front cover plate, and the inlet ring is arranged in cooperation with the concave portion of the inlet pipe; the characteristic is that: the outer circumferential surface of the inlet ring is provided with a An adjusting ring is provided, which is rotatably arranged relative to the inlet ring. The adjusting ring rotates under the impact of the reflux liquid on the outer side of the front cover plate. The adjusting ring includes a ring body, a first guide blade, and a first connecting hole. The outer peripheral surface of the ring body is provided with a first guide blade, and a plurality of first guide blades are evenly distributed along the circumferential direction. The left end face of the inlet ring is connected to the end cover ring through a connecting piece, and a matching groove is formed between the end cover ring and the inlet ring. The ring body is arranged in the matching groove, and one or more first connecting holes are opened on the ring body. The first connecting holes are arranged radially so that the gap between the ring body and the matching groove is filled with dynamic liquid.

[0006] Furthermore, the inlet ring is provided with one or more second communicating holes, which are arranged radially and on the right side of the adjusting ring or the ring body, so that part of the reflux liquid can flow back to the inlet of the blade in advance through the second communicating holes.

[0007] Furthermore, the inner circumferential surface of the inlet ring is fixedly provided with second guide vanes, a plurality of second guide vanes are evenly distributed along the circumferential direction, and an axial length of the second guide vanes is greater than the sum of the axial lengths of the adjustment ring and the second connecting hole.

[0008] Furthermore, a groove is provided on the second guide vane, and the position of the groove is arranged corresponding to the position of the second connecting hole, that is, the groove and the second connecting hole have approximately the same axial position; the radial depth of the groove is greater than half of the radial width of the second guide vane and less than the radial width of the second guide vane.

[0009] Furthermore, an inclined portion is provided at the downstream end of the second guide vane, the inclined portion is provided adjacent to the groove, and the inner diameter of the inclined portion is smaller than the inner diameter of the groove top, that is, the inclined portion extends radially inward from the groove, and the angle between the inclined portion and the rotation axis of the impeller is 5°-30°; the axial length of the second guide vane is approximately equal to the axial length of the inlet ring.

[0010] Furthermore, a third guide vane is fixedly provided on the outer circumferential surface of the inlet ring, a plurality of the third guide vanes are evenly distributed along the circumferential direction, and the third guide vanes are provided adjacent to the second connecting hole.

[0011] Further, the radial width of the third guide blade is smaller than the radial width of the first guide blade, the cross section of the third guide blade is triangular, and the radial width of the left end of the third guide blade is smaller than the radial width of the right end.

[0012] Furthermore, one or more third connecting holes are provided on the inlet ring, and the third connecting holes respectively connect the matching groove and the flow channel between two adjacent second guide blades, so that the liquid in the matching groove can partially flow through the third connecting holes to the flow channel between two adjacent second guide blades, thereby adjusting the rotation effect of the adjustment ring and the pressure distribution at the impeller inlet.

[0013] Further, the aperture diameter / cross-sectional area of ​​the second communicating hole>the aperture diameter / cross-sectional area of ​​the first communicating hole>the aperture diameter / cross-sectional area of ​​the third communicating hole.

[0014] Furthermore, the aperture / cross-sectional area of ​​the second connecting hole is 2-7 times the aperture / cross-sectional area of ​​the first connecting hole, and the aperture / cross-sectional area of ​​the first connecting hole is 2-5 times the aperture / cross-sectional area of ​​the third connecting hole; the first guide blade, the second guide blade, and the third guide blade are arc-shaped or straight-plate guide blades, and their inclination direction is inclined relative to the rotation axis of the impeller.

[0015] The fire pump of the present invention improves the small flow hump phenomenon. The adjusting ring rotates under the impact of the reflux liquid on the outer side of the front cover plate. The second connecting hole allows part of the reflux liquid to flow back to the inlet of the blade in advance through the second connecting hole. Compared with the prior art (such as Figure 1 As shown in the figure, it can improve the regulating effect of unsteady flow and pressure pulsation at the inlet of the fire pump, reduce cavitation performance and inlet secondary flow, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump.

[0016] The present invention can better improve the regulating effect of the unsteady flow and pressure pulsation at the inlet of the fire pump through the design of the second guide vane and the third guide vane, can better reduce the cavitation performance and the inlet secondary flow, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a fire pump in the prior art;

[0018] Figure 2 This is a schematic diagram of the structure of a fire pump for improving the small flow hump phenomenon of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of a fire pump for improving the small flow hump phenomenon of the present invention;

[0020] Figure 4 This is a schematic diagram of the partially enlarged structure of a fire pump for improving the small flow hump phenomenon of the present invention.

[0021] In the figure: volute 1, front side wall 11, inlet pipe 12, water pressure chamber 13, centrifugal impeller 2, rotating shaft 3, front cover plate 21, rear cover plate 22, blades 23, inlet ring 24, adjustment ring 25, second guide vane 26, second connecting hole 27, third guide vane 28, end cover ring 29, ring body 30, first guide vane 31, first connecting hole 32, groove 33, inclined portion 34, third connecting hole 35. DETAILED DESCRIPTION

[0022] In order to make the technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described in detail in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present invention, which are only used to explain the present invention, not to limit the present invention. It should be noted that, for the convenience of description, only the parts / structures related to the present invention are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0023] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present invention should be the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0025] like Figure 2-4As shown, a fire pump for improving the hump phenomenon of small flow rate includes a volute 1, a centrifugal impeller 2, and a rotating shaft 3. The impeller 2 is rotatably installed in the volute 1, and the impeller 2 is installed on the rotating shaft 3. The rotating shaft 3 is connected to the motor drivingly. The volute 1 includes a front side wall 11, an inlet pipe 12, and a pressure water chamber 13. The inlet pipe 12 and the pressure water chamber 13 are respectively connected to the upstream and downstream of the front side wall 11. The impeller 2 includes a front cover plate 21, a rear cover plate 22, blades 23, and an inlet ring 24. A plurality of blades 23 are evenly distributed along the circumferential direction and connected between the front cover plate 21 and the rear cover plate 22. The inlet end of the front cover plate 21 is provided with an inlet ring 24, and the inlet ring 24 is corresponding to / matched with the recessed portion of the inlet pipe 12; it is characterized in that: the outer peripheral surface of the inlet ring 24 is provided with an adjusting ring 25, and the adjusting ring 25 is relatively The inlet ring 24 is rotatably arranged, and the adjustment ring 25 rotates under the impact of the reflux liquid on the outer side of the front cover plate 21 (the reflux liquid impacts the first guide blade 31 to cause the adjustment ring 25 to rotate). The adjustment ring 25 includes a ring body 30, a first guide blade 31, and a first connecting hole 32. The outer peripheral surface of the ring body 30 is provided with a first guide blade 31, and a plurality of first guide blades 31 are evenly distributed along the circumferential direction; the left end face of the inlet ring 24 is connected to the end cover ring 29 through a threaded connector, and a matching groove is formed between the end cover ring 29 and the inlet ring 24. The ring body 30 is arranged in the matching groove, and one or more first connecting holes 32 are opened on the ring body 30. The first connecting holes 32 are arranged radially, so that the small gap between the ring body 30 and the matching groove is filled with dynamic liquid (similar to the effect of a liquid hydrodynamic bearing).

[0026] The inlet ring 24 is provided with one or more second connecting holes 27 , which are arranged radially and on the right side of the adjusting ring 25 or the ring body 30 , so that part of the reflux liquid can flow back to the inlet of the blade 23 in advance through the second connecting holes 27 .

[0027] The fire pump of the present invention improves the small flow hump phenomenon. The adjusting ring 25 rotates under the impact of the reflux liquid on the outer side of the front cover plate 21. The second connecting hole 27 allows part of the reflux liquid to flow back to the inlet of the blade 23 in advance through the second connecting hole 27. Compared with the prior art (such as Figure 1 As shown in the figure, it can improve the regulating effect of unsteady flow and pressure pulsation at the inlet of the fire pump, reduce cavitation performance and inlet secondary flow, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump.

[0028] In one embodiment, the inner circumferential surface of the inlet ring 24 is fixedly provided with a second guide vane 26, and a plurality of second guide vanes 26 are evenly distributed along the circumferential direction, and the axial length of the second guide vane 26 is greater than the sum of the axial lengths of the adjustment ring 25 and the second connecting hole 27. The present invention can promote / improve the reflux effect of the reflux liquid at the upstream end of the inlet ring 24 to the inlet of the blade 23 through the design of the second guide vane 26.

[0029] Furthermore, a groove 33 is provided on the second guide vane 26, and the position of the groove 33 is arranged corresponding to the position of the second connecting hole 27, that is, the groove 33 and the second connecting hole 27 have approximately the same axial position; the radial depth of the groove 33 is greater than half of the radial width of the second guide vane 26 and is less than the radial width of the second guide vane 26.

[0030] The downstream end of the second guide vane 26 is provided with an inclined portion 34, which is arranged adjacent to the groove 33, and the inner diameter of the inclined portion 34 is smaller than the inner diameter of the groove top of the groove 33, that is, the inclined portion 34 extends radially inward from the groove 33, and the angle between the inclined portion 34 and the rotation axis of the impeller 2 is 10°-18°; the axial length of the second guide vane 26 is substantially equal to the axial length of the inlet ring 24. The present invention can promote / improve the reflux effect of the reflux liquid in the second connecting hole 27 to the inlet of the blade 23 through the design of the groove 33 and the inclined portion 34.

[0031] In one embodiment, a third guide vane 28 is fixedly disposed on the outer circumferential surface of the inlet ring 24. A plurality of third guide vanes 28 are evenly distributed along the circumferential direction, and the third guide vanes 28 are disposed adjacent to the second connecting hole 27. The design of the third guide vane 28 can promote the return liquid to flow into the second connecting hole 27.

[0032] Furthermore, the radial width of the third guide blade 28 is smaller than the radial width of the first guide blade 31, the cross section of the third guide blade 28 is triangular, and the radial width of the left end of the third guide blade 28 is smaller than the radial width of the right end. The present invention can further promote the flow of reflux liquid into the second connecting hole 27 through the matching design of the third guide blade 28 and the first guide blade 31.

[0033] The present invention can better improve the regulating effect of the unsteady flow and pressure pulsation at the inlet of the fire pump through the design of the second guide vane 26 and the third guide vane 28, and can better reduce the cavitation performance and the inlet secondary flow, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump.

[0034] In one embodiment, one or more third connecting holes 35 are provided on the inlet ring 24, and the third connecting holes 35 respectively connect the matching groove and the flow channel between two adjacent second guide blades 26, so that the liquid in the matching groove can partially flow through the third connecting holes 35 to the flow channel between two adjacent second guide blades 26, thereby adjusting the rotation effect of the adjustment ring 25 and the pressure distribution at the inlet of the impeller 2.

[0035] Further, the hole diameter / cross-sectional area of ​​the second communication hole 27 > the hole diameter / cross-sectional area of ​​the first communication hole 32 > the hole diameter / cross-sectional area of ​​the third communication hole 35 .

[0036] The aperture / cross-sectional area of ​​the second communication hole 27 is 2-6 times the aperture / cross-sectional area of ​​the first communication hole 32 , and the aperture / cross-sectional area of ​​the first communication hole 32 is 2-4 times the aperture / cross-sectional area of ​​the third communication hole 35 .

[0037] In one embodiment, the first guide vane 31 , the second guide vane 26 , and the third guide vane 28 are arc-shaped or straight-plate-shaped guide vanes, and their inclination directions are inclined relative to the rotation axis of the impeller 2 .

[0038] The fire pump of the present invention improves the small flow hump phenomenon. By optimizing the design of the adjustment ring 25, the second guide vane 26, the second connecting hole 27, the third guide vane 28 and / or the third connecting hole 35, the regulation effect of the unsteady flow and pressure pulsation at the inlet of the fire pump can be improved, the cavitation performance and the inlet secondary flow can be reduced, thereby improving or eliminating the small flow hump phenomenon and improving the hydraulic performance and operation stability of the fire pump.

[0039] The above-mentioned implementation modes are for explanation of the present invention rather than limitation of the present invention. It can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fire pump for improving a small flow hump phenomenon, comprising a volute (1), a centrifugal impeller (2), and a rotating shaft (3), wherein the impeller is rotatably mounted in the volute, the impeller is mounted on the rotating shaft, the rotating shaft is drivingly connected to a motor, the volute comprises a front side wall (11), an inlet pipe (12), and a water pressure chamber (13), the inlet pipe and the water pressure chamber are respectively connected to the upstream and downstream of the front side wall, the impeller comprises a front cover plate (21), a rear cover plate (22), blades (23), and an inlet ring (24), a plurality of blades are evenly distributed along the circumferential direction and connected between the front cover plate and the rear cover plate, an inlet ring is arranged at the inlet end of the front cover plate, and the inlet ring is arranged to cooperate with the recessed portion of the inlet pipe; Features: An adjustment ring (25) is arranged on the outer circumference of the inlet ring (24). The adjustment ring is rotatably arranged relative to the inlet ring. The adjustment ring rotates under the impact of the reflux liquid on the outer side of the front cover plate. The adjustment ring comprises a ring body (30), a first guide blade (31), and a first connecting hole (32). The outer circumference of the ring body is provided with a first guide blade, and a plurality of first guide blades are evenly distributed along the circumferential direction. The left end face of the inlet ring is connected to an end cover ring (29) via a connecting piece. A matching groove is formed between the end cover ring and the inlet ring. The ring body is arranged in the matching groove. One or more first connecting holes (32) are opened on the ring body. The first connecting holes are arranged in the radial direction so that the gap between the ring body and the matching groove is filled with dynamic liquid.

2. A fire pump for improving the small flow hump phenomenon as claimed in claim 1, characterized in that: The inlet ring (24) is provided with one or more second communication holes (27), the second communication holes being arranged radially and being arranged on the right side of the adjustment ring (25) or the ring body (30), so that part of the reflux liquid can flow back to the inlet of the blade in advance through the second communication holes.

3. A fire pump for improving the small flow hump phenomenon as claimed in claim 2, characterized in that: The inner circumferential surface of the inlet ring (24) is fixedly provided with a second guide vane (26), a plurality of the second guide vanes are evenly distributed along the circumferential direction, and the axial length of the second guide vane is greater than the sum of the axial lengths of the adjustment ring (25) and the second connecting hole (27).

4. A fire pump for improving the small flow hump phenomenon as claimed in claim 3, characterized in that: The second guide blade (26) is provided with a groove (33), the position of the groove being arranged corresponding to the position of the second connecting hole (27), that is, the groove and the second connecting hole have the same axial position; the radial depth of the groove is greater than half the radial width of the second guide blade and less than the radial width of the second guide blade.

5. A fire pump for improving the small flow hump phenomenon as claimed in claim 4, characterized in that: The downstream end of the second guide vane (26) is provided with an inclined portion (34), which is arranged adjacent to the groove (33), and the inner diameter of the inclined portion is smaller than the inner diameter of the groove top, that is, the inclined portion extends radially inward from the groove, and the angle between the inclined portion and the rotation axis of the impeller is 5°-30°; the axial length of the second guide vane is equal to the axial length of the inlet ring (24).

6. A fire pump for improving the small flow hump phenomenon as claimed in claim 5, characterized in that: The outer circumferential surface of the inlet ring (24) is fixedly provided with a third guide vane (28), a plurality of the third guide vanes are evenly distributed along the circumferential direction, and the third guide vanes are arranged closely adjacent to the second connecting hole (27).

7. A fire pump for improving the small flow hump phenomenon as claimed in claim 6, characterized in that: The radial width of the third guide blade (28) is smaller than the radial width of the first guide blade (31), the cross section of the third guide blade is triangular, and the radial width of the left end of the third guide blade is smaller than the radial width of the right end.

8. A fire pump for improving the small flow hump phenomenon as claimed in claim 7, characterized in that: The inlet ring (24) is provided with one or more third communication holes (35), the third communication holes respectively communicating with the matching groove and the flow passage between two adjacent second guide blades (26), so that part of the liquid in the matching groove can flow through the third communication holes to the flow passage between two adjacent second guide blades, thereby being able to adjust the rotation effect of the adjustment ring (25) and the pressure distribution at the impeller inlet.

9. A fire pump for improving the small flow hump phenomenon as claimed in claim 8, characterized in that: The hole diameter / cross-sectional area of ​​the second connecting hole (27)>the hole diameter / cross-sectional area of ​​the first connecting hole (32)>the hole diameter / cross-sectional area of ​​the third connecting hole (35).

10. A fire pump for improving the small flow hump phenomenon as claimed in claim 8, characterized in that: The aperture / cross-sectional area of ​​the second connecting hole (27) is 2-7 times the aperture / cross-sectional area of ​​the first connecting hole (32), and the aperture / cross-sectional area of ​​the first connecting hole is 2-5 times the aperture / cross-sectional area of ​​the third connecting hole (35); the first guide blade (31), the second guide blade (26), and the third guide blade (28) are arc-shaped or straight-plate-shaped guide blades, and their inclination direction is inclined relative to the rotation axis of the impeller.

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