Connecting structure for split surfaces of double-shell multi-stage pump

Abstract

The invention relates to a double-shell multistage pump split face connecting structure which comprises an inner shell and an outer barrel arranged on the outer side of the inner shell in a sleeving mode, the outer barrel is provided with an inlet flange and an outlet flange, the outer barrel and a pump cover jointly form a sealing cavity, and the inner shell is sealed in the sealing cavity; the rotor part is arranged in the inner shell and forms a flow passage part of the pump together with the transition flow channel of the inner shell; the inner shell comprises an upper shell body and a lower shell body, and the upper shell body and the lower shell body are arranged in a central symmetry mode. An axially split flange face is arranged between the upper shell and the lower shell, and connecting devices are arranged on the two sides of the axially split flange face; the four corners of the middle opening face are each provided with a limiting mechanism. An inner shell anti-rotation positioning block is arranged on the end face of the high-pressure side of the inner shell, and an inner shell circumferential positioning block is arranged on the middle plane of the upper shell and the middle plane of the lower shell. The radial size of the inner shell is reduced, so that the radial size of the whole pump is small, and the transportation and installation space is reduced; the weight of the pump body and the cost are reduced. According to the connecting mode of the middle open face, the casting difficulty of the middle open face of the inner shell is reduced.

Description

Technical Field

[0001] The invention relates to a connection structure, in particular to a connection structure for the open face of a double-shell multistage pump, which reduces the difficulty of casting the open face of an inner shell, reduces the radial size of the inner shell, has a stable structure and low transportation cost. Background Art

[0002] Double-casing multistage centrifugal pumps are generally used in the petrochemical and power industries, especially for conveying high-temperature and high-pressure chemical media. In the prior art double-casing multistage centrifugal pumps, such as the BB5 pump, the inner casing is divided into segmental or split type. The connection method of the split inner casing is as follows: Figure 7 As shown in the figure, the middle open surface is extended to form a flange surface, threaded holes are machined on the flange surface, and then studs are used for connection. This connection method causes the radial size of the inner shell to become larger, which increases the overall radial size of the pump and the cost. At the same time, it increases the difficulty of casting. Summary of the invention

[0003] In view of the above problems, the main purpose of the present invention is to provide a connection structure for the open surface of a double-casing multi-stage pump, which reduces the difficulty of casting the open surface of the inner casing, reduces the radial size of the inner casing, has a stable structure and low transportation cost.

[0004] The present invention solves the above technical problems through the following technical solutions: a connection structure of an open surface in a double-shell multistage pump, the connection structure of the open surface in the double-shell multistage pump comprises: an inner shell and an outer cylinder sleeved on the outer side of the inner shell.

[0005] The outer cylinder is provided with an inlet flange and an outlet flange. The outer cylinder and the pump cover together form a sealed cavity, and the inner shell is sealed in the sealed cavity.

[0006] The rotor component is installed inside the inner casing, and together with the transition flow channel of the inner casing, constitutes the flow-passing component of the pump.

[0007] The inner shell comprises an upper shell and a lower shell, which are arranged in a central symmetrical manner; a centrally opened flange surface is arranged between the upper shell and the lower shell, and connecting devices are arranged on both sides of the centrally opened flange surface; a limiting mechanism is arranged at each of the four corners of the centrally opened surface.

[0008] An inner casing anti-rotation positioning block is arranged on the high-pressure side end face of the inner casing, and an inner casing circumferential positioning block is arranged on the middle plane of the upper casing and the lower casing.

[0009] In a specific implementation example of the present invention, the connecting device includes an inner surface and an outer surface; the inner surface and the outer surface are clearance-fitted, the inner surface is provided with a threaded hole; the outer surface is provided with a corresponding through hole; the connecting device is provided with a fastening device, which includes multiple sets of gaskets and hexagon socket head screws.

[0010] In a specific implementation example of the present invention, each limiting mechanism includes a wedge block, a trapezoidal groove and two set screws; the wedge block is installed in the trapezoidal groove, and the wedge block is tightened by the set screws.

[0011] In a specific implementation example of the present invention, the taper angle θ of the wedge block is 5 to 12°.

[0012] In a specific implementation example of the present invention, the taper angle of the trapezoidal groove and the taper angle θ of the wedge block are the same.

[0013] In a specific implementation example of the present invention, the distance between the small end surface of the trapezoidal groove and the small end surface of the wedge-shaped block is 2 to 5 mm.

[0014] In a specific implementation example of the present invention, the distance between the large end surface of the trapezoidal groove and the large end surface of the wedge block is 1 / 3 of the width of the wedge block.

[0015] In a specific implementation example of the present invention, the length of the trapezoidal groove is 2 to 5 mm longer than the length of the wedge-shaped block.

[0016] In a specific implementation example of the present invention, the inner shell assembly process steps are as follows:

[0017] Step (1), put the upper shell on the lower shell and adjust the center;

[0018] Step (2), installing the wedge block in the trapezoidal groove and tightening the wedge block with a set screw;

[0019] Step (3): Install the gasket and the hexagon socket head screw.

[0020] In a specific implementation example of the present invention, during the disassembly process of the connection structure, when the upper shell and the lower shell of the inner shell are separated, the following steps are followed: Step (1), first remove the set screws of the wedge block;

[0021] Step (2), loosen the wedge block with a tool, and use the tool to clamp the wedge block cap to pull out the wedge block;

[0022] Step (3), then remove the hexagon socket head screw and gasket on the split face connection device;

[0023] Step (4): Finally, separate the upper shell from the lower shell to complete the disassembly of the inner shell.

[0024] The positive progressive effect of the present invention is that the open-surface connection structure of the double-shell multi-stage pump provided by the present invention has the following advantages compared with the common technology: the open-surface connection method of the present invention reduces the difficulty of casting the open-surface of the inner shell, and the design methods such as the limiting structure, the anti-rotation positioning block of the inner shell, and the circumferential positioning block of the inner shell make the present invention low in casting difficulty, stable in structure, and low in transportation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 It is a schematic diagram of the open surface structure of the inner shell in the present invention.

[0027] Figure 3 It is a schematic diagram of the connection device in the present invention.

[0028] Figure 4 It is a schematic diagram of the limiting structure in the present invention.

[0029] Figure 5 It is a cross-sectional schematic diagram of the limiting structure in the present invention.

[0030] Figure 6-1 It is a schematic diagram of the wedge block structure in the present invention.

[0031] Figure 6-2 Schematic diagram of the position of the wedge block taper angle θ in the present invention.

[0032] Figure 7 It is a schematic diagram of the overall structure of the currently common similar technologies.

[0033] The following are the names corresponding to the labels in the present invention:

[0034] Outer shell 1, pump inlet 11, pump outlet 12, inner shell 2, upper shell 21, lower shell 22, center open surface connecting device 23, connecting device inner surface 231, connecting device outer surface 232, gasket 234, hexagon socket head screw 235, limiting mechanism 24, wedge block 241, set screw 242, trapezoidal groove 243, inner shell anti-rotation positioning block 25, inner shell circumferential positioning block 26, pump cover 3, rotor component 4. DETAILED DESCRIPTION

[0035] Preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to illustrate the technical solutions of the present invention in detail.

[0036] Figure 1 It is a schematic diagram of the overall structure of the present invention, Figure 2 FIG. 1 is a schematic diagram of the open surface structure of the inner shell in the present invention. Figure 1-2As shown: the connection structure of the open surface of the double-shell multistage pump provided by the present invention includes: an inner shell 2, an outer cylinder 1 sleeved on the outside of the inner shell 2, the outer cylinder 1 is provided with an inlet flange 11 and an outlet flange 12, the outer cylinder 1 and the pump cover 3 together form a sealed cavity, the inner shell 2 is sealed in the sealed cavity, the rotor component 4 is installed inside the inner shell 2, and together with the transition flow channel of the inner shell 2, it constitutes a flow component of the pump, the inner shell 2 includes an upper shell 21 and a lower shell 22, the upper shell 21 and the lower shell 22 are arranged in a central symmetrical manner, an open flange surface is provided between the upper shell 21 and the lower shell 22, connecting devices 23 are provided on both sides of the open flange surface, a limiting mechanism 24 is provided on each of the four corners of the open surface, an inner shell anti-rotation positioning block 25 is provided on the high-pressure side end face of the inner shell, and an inner shell circumferential positioning block 26 is provided on the middle plane on the upper shell 21 and the lower shell 22.

[0037] Figure 3 It is a schematic diagram of the connection device in the present invention, such as Figure 3 As shown: the connecting device 23 includes an inner surface 231 and an outer surface 232 (see Figure 2 ); the inner connecting surface 231 and the outer connecting surface 232 are clearance-matched, and the inner connecting surface 231 and the outer connecting surface 232 can limit the upper shell 21 and the lower shell 22 to prevent the upper shell 21 and the lower shell 22 from sliding relative to each other in the radial direction. The inner connecting surface 231 is provided with a threaded hole; the outer connecting surface 232 is provided with a corresponding through hole; the connecting device 23 is provided with a fastening device, which includes multiple sets of gaskets 234 and hexagon socket head screws 235.

[0038] The inner housing anti-rotation positioning block 25 (see Figure 1 and 2 ) is to prevent the inner housing 2 from rotating in the inner cavity of the outer housing 1 during the operation of the pump, so as to ensure the normal operation of the pump and extend its service life. The inner housing anti-rotation positioning block 25 is arranged on the high-pressure side end face of the inner housing.

[0039] The inner shell circumferential positioning block 26 (see Figure 1 and 2 ) so that the inner shell 2 does not produce axial displacement and circumferential movement with the outer cylinder 1. The inner shell circumferential positioning block 26 is arranged on the middle plane of the upper shell 21 and the lower shell 22.

[0040] During normal operation of the pump of the present invention, the pressure outside the inner housing 2 is greater than the internal pressure, that is, the inner housing 2 is subjected to external pressure. However, during the start-up of the pump, when the outer side of the inner housing 2 is not filled with liquid, the internal pressure of the inner housing 2 is greater than the external pressure, and a gap may be generated between the middle opening flange surfaces of the upper housing 21 and the lower housing 22. In order to prevent this possibility, a limit mechanism 24 is provided. Figure 4 It is a schematic diagram of the limiting structure in the present invention, Figure 5 is a cross-sectional schematic diagram of the limiting structure in the present invention, Figure 6-1 It is a schematic diagram of the wedge block structure in the present invention, Figure 6-2 Schematic diagram of the position of the wedge block cone angle θ in the present invention. As shown in the above figure: a total of 4 limiting mechanisms 24 are set, and one limiting mechanism 24 is set in each of the four directions of the middle open surface. Each limiting mechanism 24 includes a wedge block 241, a trapezoidal groove 243 and two set screws 242. The wedge block 241 is shown in Figure 6, and its cross-section is trapezoidal. The wedge block cap can be set to be circular, triangular, polygonal, etc. The two parallel surfaces of the trapezoidal cross-section cut the wedge cap flat to keep it in the same plane. The wedge block 241 is installed in the trapezoidal groove 243, and the wedge block 241 is tightened with a set screw 242.

[0041] In the specific implementation of the present invention, the taper angle θ of the wedge block 241 can be 5 to 12°. In the specific implementation, the taper angle θ of the trapezoidal groove 243 and the taper angle θ of the wedge block 241 are the same. The distance between the small end face of the trapezoidal groove 243 and the small end face of the wedge block 241 can be 2 to 5 mm. The distance between the large end face of the trapezoidal groove 243 and the large end face of the wedge block 241 is 1 / 3 of the width of the wedge block. The length of the trapezoidal groove can be 2 to 5 mm longer than the length of the wedge block. The above parameters can be modified to other values ​​or ranges according to specific needs.

[0042] The assembly and disassembly processes of the present invention are respectively as follows:

[0043] Inner housing assembly process steps:

[0044] 1. Put the upper shell 21 on the lower shell 22 and adjust the center;

[0045] 2. Install the wedge block 241 in the trapezoidal groove 243 and tighten the wedge block 241 with the set screw 242;

[0046] 3. Install the gasket 234 and the hexagon socket head screw 235.

[0047] During the disassembly process, when the upper shell 21 and the lower shell 22 of the inner shell 2 are separated, the following steps are followed:

[0048] 1. Remove the set screw 242 of the wedge block first;

[0049] 2. Use a tool to pry the wedge block 241 loose, and use the tool to clamp the wedge block cap to pull out the wedge block 241;

[0050] 3. Then remove the hexagon socket head screw 235 and the gasket 234 on the split face connection device 23;

[0051] 4. Finally, separate the upper shell 21 from the lower shell 22 to complete the disassembly of the inner shell 2.

[0052] The present invention adopts the inner housing anti-rotation positioning block 25 to prevent the inner housing 2 from rotating in the inner cavity of the outer housing 1 during the operation of the pump, thereby ensuring the normal operation of the pump and extending its service life.

[0053] In the present invention, the inner shell circumferential positioning block 26 is adopted to prevent the inner shell 2 from axial displacement and circumferential movement with the outer cylinder 1 .

[0054] The radial dimension of the inner casing of the present invention is reduced, so that the radial dimension of the whole pump is small, the transportation and installation space is reduced, the weight of the pump body is reduced, and the cost is reduced. The open surface connection method of the present invention reduces the difficulty of casting the open surface in the inner casing.

[0055] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected, and the scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A connection structure of an open surface in a double-shell multistage pump, characterized in that: The open-face connection structure of the double-shell multistage pump comprises: an inner shell, an outer cylinder sleeved outside the inner shell, The outer cylinder is provided with an inlet flange and an outlet flange, and the outer cylinder and the pump cover together form a sealed cavity, sealing the inner shell in the sealed cavity; The rotor component is installed inside the inner casing, and together with the transition flow channel of the inner casing, it forms the flow-passing component of the pump; The inner shell comprises an upper shell and a lower shell, and the upper shell and the lower shell are arranged in a central symmetric manner; a centrally opened flange surface is provided between the upper shell and the lower shell, and connecting devices are provided on both sides of the centrally opened flange surface; a limiting mechanism is provided at each of the four corners of the centrally opened surface; An inner casing anti-rotation positioning block is arranged on the high-pressure side end face of the inner casing, and an inner casing circumferential positioning block is arranged on the middle planes on the upper casing and the lower casing.

2. The open-surface connection structure of a double-shell multistage pump according to claim 1, characterized in that: The connecting device comprises an inner surface and an outer surface; the inner surface and the outer surface are clearance-matched, the inner surface is provided with a threaded hole; the outer surface is provided with a corresponding through hole; the connecting device is provided with a fastening device, which comprises a plurality of gaskets and hexagon socket head screws.

3. The open-surface connection structure of a double-casing multistage pump according to claim 2, characterized in that: Each limiting mechanism includes a wedge block, a trapezoidal groove and two set screws; the wedge block is installed in the trapezoidal groove, and the wedge block is tightened by the set screws.

4. The open-surface connection structure of a double-shell multistage pump according to claim 3, characterized in that: The taper angle θ of the wedge block is 5 to 12°.

5. The open-surface connection structure of a double-casing multistage pump according to claim 4, characterized in that: The taper angle θ of the trapezoidal groove and the taper angle θ of the wedge block are the same.

6. The open-surface connection structure of a double-casing multistage pump according to claim 5, characterized in that: The distance between the small end face of the trapezoidal groove and the small end face of the wedge block is 2 to 5 mm.

7. The open-surface connection structure of a double-casing multistage pump according to claim 3, characterized in that: The distance between the large end surface of the trapezoidal groove and the large end surface of the wedge block is 1 / 3 of the width of the wedge block.

8. The open-surface connection structure of a double-casing multistage pump according to claim 7, characterized in that: The length of the trapezoidal groove is 2 to 5 mm longer than the length of the wedge block.

9. The open-surface connection structure of a double-casing multistage pump according to claim 3, characterized in that: The inner shell assembly process steps are as follows: Step (1), put the upper shell on the lower shell and adjust the center; Step (2), installing the wedge block in the trapezoidal groove and tightening the wedge block with a set screw; Step (3): Install the gasket and the hexagon socket head screw.

10. The open-surface connection structure of a double-casing multistage pump according to claim 3, characterized in that: During the disassembly process of the connection structure, when the upper shell and the lower shell of the inner shell are separated, the following steps are followed: Step (1), first remove the set screws of the wedge block; Step (2), loosen the wedge block with a tool, and use the tool to clamp the wedge block cap to pull out the wedge block; Step (3), then remove the hexagon socket head screw and gasket on the split face connection device; Step (4): Finally, separate the upper shell from the lower shell to complete the disassembly of the inner shell.

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