CN111207080B

CN111207080B - Chemical pump with shaft-split middle-opening conveniently-disassembled structure

Info

Publication number: CN111207080B
Application number: CN202010074322.6A
Authority: CN
Inventors: 陈科
Original assignee: Yueqing Ruiyi Economic Information Consulting Co ltd
Current assignee: Yueqing Ruiyi Economic Information Consulting Co.,Ltd.
Priority date: 2020-01-22
Filing date: 2020-01-22
Publication date: 2020-12-15
Anticipated expiration: 2040-01-22
Also published as: CN112392729A; CN111207080A; CN112392730A

Abstract

The invention discloses a chemical pump with a shaft-divided middle-division convenient-to-disassemble structure, which comprises a pump body, an impeller and a pump shaft, wherein the pump body is in a side-suction side-outlet type, the pump body comprises an end connecting disc, a suction chamber, an impeller chamber, a water outlet and an end face, the suction chamber is close to the impeller chamber, the side of the suction chamber, which is far away from the impeller chamber, is provided with the end connecting disc, the side of the impeller chamber, which is far away from the suction chamber, is provided with the end face, the side of the suction chamber is provided with the water inlet, the side of the impeller chamber is provided with the water outlet, the end face and the end connecting disc are provided with through holes for communicating the. The multistage accumulated pump body and working parts such as the impeller, the pump shaft and the like in the pump body can realize synchronous working of a plurality of pump cavities, and the flow and the lift range are enlarged by the chemical pump which is transformed in a mode of overlapping single-stage pump heads.

Description

Chemical pump with shaft-split middle-opening conveniently-disassembled structure

Technical Field

The invention relates to the field of chemical pumps, in particular to a chemical pump with a shaft split structure and a split structure.

Background

The chemical pump is a circulating or pressurizing device which is used in a large number in the chemical industry and provides flowing power for a medium of a process system.

Among the prior art, chemical pump all is single pump head design, a pump head is taken to motor traction, the operating mode application scope of single pump head is limited, and single chemical pump need set up mechanical seal in order to prevent leaking in its pump shaft passes pump case department, the machine of chemical industry occasion seals reliable operating condition that needs, centrifugal pump design and operation requirement under the different operating modes have been stipulated with bearing seal system API682 for the pump to petrochemical industry institute's petrochemical industry design specification API610, the bearing seal of chemical pump all needs complicated washing pipeline basically, it is loaded down with trivial details to set up, thereby when needing newly-increased chemical pump because the operating mode adjustment, also need to connect again and join in marriage washing pipeline.

Disclosure of Invention

The invention aims to provide a chemical pump with a shaft split structure convenient to disassemble, which aims to solve the problems in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a take chemical pump of axle division zhong kaishu structure, the chemical pump includes the pump body, the impeller, the pump shaft, the pump body is the side-draught side play formula pump body, the pump body includes the end connection pad, the suction chamber, the impeller chamber, delivery port and terminal surface, suction chamber and impeller chamber next-door neighbour, one side that the suction chamber deviates from the impeller chamber sets up the end connection pad, one side that the impeller chamber deviates from the suction chamber sets up the terminal surface, the suction chamber side sets up the water inlet, the impeller chamber side sets up the delivery port, be equipped with the through-hole on terminal surface and the end connection pad, through-hole intercommunication suction chamber and impeller chamber, the through-hole diameter on the terminal.

Cancel the axial of traditional chemical pump structure of intaking, change into the side structure of intaking, give way the axial space, thereby realize the series structure of the multistage pump body, the terminal surface is the rear side of the pump body, this next-door neighbour impeller chamber, the through-hole of terminal surface central authorities is the position department of putting into the impeller, the impeller is dealt with into from the back lid of the pump body, thereby when pump chamber is dismantled to needs, can directly accomplish the dismantlement work through dismantling the apron on the terminal surface, afterwards, directly take the impeller together with the pump shaft from the pump chamber, both conveniently change or wash the impeller, also conveniently clear up the pump chamber, the impeller need not dismantle with being connected of pump shaft, thereby need not to carry out the axial locking force adjustment of rotor part.

The pump body that multistage adds up and impeller in it, acting parts such as pump shaft, can realize the synchronous acting of a plurality of pump chambeies, when process system reforms transform or the operating mode changes, probably single impeller also can't realize crossing operating mode adjustment or acting efficiency greatly reduced through motor frequency conversion control, reform transform the chemical industry pump through the form of stack single-stage pump head, the application range of chemical industry pump is greatly enlarged, moreover, be different from newly-increased a new chemical industry pump, through the stack mode of single-stage pump head, as long as not overpower, the motor need not be changed, also need not increase the machine and seal the flushing line, this part pipeline arrangement is very troublesome.

The chemical pump further comprises a middle pump cover, an end cover, a tail cover, an impeller nut, a shaft sleeve and a machine seal, wherein an end hole for connection is formed in the end connecting disc, a rear cover hole for connection is formed in the end face, one end face of the end cover and the end connecting disc have matched spigot features, a connecting hole which has the same central circle as the end hole is formed in the end cover, one end face of the middle pump cover is provided with a spigot feature matched with the end connecting disc, a countersunk connecting hole which has the same central circle as the end hole is formed in the middle pump cover, the other end face of the middle pump cover is provided with a spigot feature matched with the end face, a countersunk connecting hole which has the same central circle as the rear cover hole is formed in the middle pump cover, one end face of the tail cover is provided with a spigot feature matched with the end face, and a connecting hole which has the same; the end connecting disc is connected with the end cover or the middle pump cover, and the end surface of the end connecting disc is connected with the tail cover or the middle pump cover;

the middle pump cover plays a role in connection, the end face of one pump body and the end connecting disc of the other pump body are respectively connected to two sides between the two pump bodies, the pump bodies are casting parts, therefore, structures with certain precise sizes are inconvenient to process, after the middle pump cover is added, the middle pump cover is a full-machined workpiece of a flat plate, a plurality of structures can be manufactured on the end face of the middle pump cover so as to meet corresponding design requirements, for example, the end face of one end connected with the end face can be provided with a plurality of spiral grooves, then the back face of the impeller is provided with auxiliary blades, compared with the simple auxiliary blades, better axial force balance can be realized, for example, a seal or a bearing can be arranged at the central position of the middle pump cover, the seal is used for blocking leakage between the two pump bodies, when the pump body sections are more, the pump shaft can be reliably supported by the bearing arranged in the middle pump cover, need be connected with the pump body of both sides respectively, so, it is necessary to use the fastener to connect respectively, moreover, need pay attention to structural design, dodges out and interferes the position, uses the counter sink to connect, and the axial dimension is saved to the head of holding the screw.

The end connection disc side of the first stage pump body needs to be sealed by a pump cover with a central hole, namely an end cover, while the end face side of the last stage pump body needs to be connected by a pump cover with a certain axial length, namely a tail cover,

the pump shaft comprises a main section, a threaded section and a transmission head, wherein a key groove is formed in the main section, an impeller is sleeved on the main section, the main section and the impeller are in transmission through a key or a spline, the threaded section is arranged at one end of the main section, the transmission head is arranged at one end, away from the main section, of the threaded section, a transmission hole is formed at one end, away from the threaded section, of the main section, the transmission hole and the transmission head are in an embedded or threaded connection relation in shape, an impeller nut is screwed on the threaded section and abuts against the end portion of a hub of the impeller, and the; the rear part of the tail cover is connected with a connecting frame used as a motor or a mounting frame connected with the motor,

a mechanical seal is arranged in the tail cover, and a mechanical seal pump shaft extends into one end of the tail cover; the pump shaft is sleeved with a shaft sleeve, and one end of the shaft sleeve is abutted against the end part of the hub on the back of the impeller. The mechanical seal in the tail cover plays a role in shaft face dynamic seal, the mechanical seal is used as a sealing element due to the fact that a chemical pump has high requirements for leakage, the mechanical seal needs to be flushed according to the requirements of API610 and 682 according to the use occasion and working condition, and the dynamic seal positions among the pump bodies of a plurality of stages are in the pump, so that if the pump bodies pumping the same medium are used in an overlapping mode, only basic mechanical seals or labyrinth rings, piston type seals and the like need to be used, interstage leakage does not leak out of the pump, and therefore the sealing requirements are not high.

The shaft sleeve is used for adjusting the axial spacing of different parts on different interstage rotors.

Further, the chemical pump still includes end axle and bearing, and end axle one end sets up the transmission blind hole that is connected with the transmission head, and the end axle other end passes through the bearing and installs the central authorities at the end cover.

The axial position of the pump shaft is required to be positioned at the position of the primary pump body, the end shaft sleeve is embedded at the end part of the pump shaft in the primary pump body and then is installed in the bearing arranged in the end cover, and the shaft shoulder of the end shaft or the positioning structure on the shaft shoulder abuts against the inner ring of the bearing to be positioned axially. Not only the axial positioning is accomplished, but also the effect of rotary support can be played for the pump shaft becomes double-ended bearing structure.

Preferably, the transmission head is a square cylinder, the transmission hole is a blind hole with a square cross section, and the transmission head and the transmission hole are connected in a direct insertion mode.

The transmission head is directly inserted into the transmission hole and connected, so that the installation is more convenient, only the insertion and the end part support are needed, and the axial locking of the pump shafts is inwards pressed through the two ends.

Furthermore, after the two pump shafts are in butt joint, a gasket is padded at the butt joint position. Since there may be machining errors in the length of the pump shaft and the axial length of the pump body, it is necessary to adjust the axial distance in order to prevent accumulation of errors. A plurality of gaskets with different thicknesses are backed up in advance, and when a new single-stage pump head is installed, the gaskets are inserted between the shafts.

As optimization, a mechanical seal is arranged in the center of the middle pump cover. A mechanical seal is arranged in the center of a middle pump cover between pump stages to prevent media from streaming between the stages.

When a plurality of pump bodies are overlapped, the inlet and the outlet of each stage of pump body are connected in series. The pump bodies can be used in parallel and also can be used in series to obtain high lift.

As optimization, the diameter of the central circle of the rear cover hole is larger than that of the central circle of the end hole; the outer edge of the end connecting disc is provided with a yielding groove, and the radial distance between the bottom of the yielding groove and the pump shaft is smaller than the radius of a central circle of the rear cover hole. The mounting hole configuration mode is that in the consideration of the dismounting direction, the abdicating groove is arranged on the end connecting disc, namely, the middle pump cover is connected with the end face at the back and is connected with the end connecting disc of another pump body at the front.

The main operation process of the invention is as follows: the medium enters the single-stage pump head from the side, and is discharged from the water outlet of the single-stage pump head after the single-stage pump head applies work and pressure, the multiple single-stage pump heads which are used in parallel can respectively pump the medium, the water inlet is collected by the suction inlet, the water outlet is collected to discharge water, the flow range of the chemical pump is expanded, and when the chemical pump is used in series, the inlet and the outlet of the multiple-stage pump heads are sequentially connected, so that the lift range is expanded.

Compared with the prior art, the invention has the beneficial effects that: the invention can realize the synchronous working of a plurality of pump cavities through a pump body with multi-stage accumulation and working parts such as an impeller, a pump shaft and the like in the pump body, and the chemical pump which is transformed by superposing single-stage pump heads is used in parallel and can respectively pump media, a suction inlet collects water, a water outlet collects water, the flow range of the chemical pump is expanded, when the chemical pump is used in series, the inlet and the outlet of the multi-stage pump heads are sequentially connected, the lift range is expanded, and the invention is different from a new chemical pump which is newly added, and the motor does not need to be replaced and does not need to add a complicated machine seal flushing pipeline as long as the power is not exceeded by the superposition mode of the single-stage; the multistage single pump head that uses, after one of them damages, remaining still can continue to work, prevents that emergency shutdown from causing danger, and the change of impeller is very convenient with the washing, and the pump chamber also only need demolish behind a set of screw and just can wash.

Drawings

In order that the present invention may be more readily and clearly understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

FIG. 1 is a schematic view of the final assembly of the present invention;

FIG. 2 is a cross-sectional view of the pump body of the present invention;

FIG. 3 is a schematic view of the pump shaft connection of the present invention;

FIG. 4 is a cross-sectional view of the intermediate pump cover of the present invention;

FIG. 5 is a partial view A of FIG. 1;

FIG. 6 is view B-B of FIG. 1;

FIG. 7 is a section C-C of FIG. 2;

fig. 8 is a partial view D of fig. 1.

In the figure: 1-pump body, 11-end connecting disc, 111-end hole, 112-abdicating groove, 12-suction chamber, 13-impeller chamber, 14-water outlet, 15-end face, 151-rear cover hole, 2-middle pump cover, 3-impeller, 4-pump shaft, 41-main section, 411-transmission hole, 42-thread section, 43-transmission head, 5-end cover, 6-tail cover, 7-end shaft, 8-bearing, 91-impeller nut, 92-shaft sleeve, 93-gasket and 94-mechanical seal.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, a chemical pump with a shaft-in-out structure, which comprises a pump body 1, an impeller 3 and a pump shaft 4, wherein the pump body 1 is a side-suction side-out pump body, as shown in fig. 2, the pump body 1 comprises an end connection disc 11, a suction chamber 12, an impeller chamber 13, a water outlet 14 and an end surface 15, the suction chamber 12 is close to the impeller chamber 13, one side of the suction chamber 12, which is far away from the impeller chamber 13, is provided with an end connection disc 11, one side of the impeller chamber 13, which is far away from the suction chamber 12, is provided with an end surface 15, as shown in fig. 6, the side of the suction chamber 12 is provided with a water inlet, the side of the impeller chamber 13 is provided with the water outlet 14, the end surface 15 and the end connection disc 11 are provided with through holes, the through holes communicate the suction chamber 12 with the impeller chamber.

Cancel the axial of traditional chemical pump structure of intaking, change into the side structure of intaking, give way the axial space, thereby realize the series structure of the multistage pump body 1, terminal surface 15 is the rear side of the pump body 1, this next-door neighbour impeller chamber 13, the through-hole of terminal surface 15 central authorities is the position department of putting into impeller 3, impeller 3 is put into from the back lid of the pump body 1, thereby when pump chamber is dismantled to needs, can be directly can accomplish dismantlement work through dismantling the apron on the terminal surface 15, afterwards, directly take out impeller 3 and pump shaft 4 from the pump chamber together with pump shaft, both conveniently change or wash impeller 3, also conveniently clear up the pump chamber, impeller 3 need not dismantle with being connected of pump shaft 4, thereby the axial locking force adjustment that need not carry out the rotor part.

The pump body 1 that multistage adds up and impeller 3 in it, acting parts such as pump shaft 4, can realize the synchronous acting of a plurality of pump chambeies, when process system reforms transform or the operating mode changes, even probably single impeller 3 also can't realize crossing operating mode adjustment or work efficiency greatly reduced through motor frequency conversion control, reform transform the chemical industry pump through the form of stack single-stage pump head, the application range of chemical industry pump is greatly enlarged, and, be different from adding a new chemical industry pump again, through the stack mode of single-stage pump head, as long as do not overpower, the motor need not be changed, also need not increase the machine and seal the flushing line, this part pipeline is arranged very troublesome.

As shown in fig. 1 to 5, the chemical pump further comprises a middle pump cover 2, an end cover 5, a tail cover 6, an impeller nut 91, a shaft sleeve 92 and a mechanical seal 94, wherein an end hole 111 for connection is arranged on an end connection disc 11, a rear cover hole 151 for connection is arranged on an end face 15, one end face of the end cover 5 and the end connection disc 11 have matched spigot characteristics, the end cover 5 is provided with a connecting hole with the same center circle as the end hole 111, one end face of the middle pump cover 2 is provided with a spigot feature matched with the end connecting disc 11, the middle pump cover 2 is provided with a countersunk connecting hole with the same center circle as the end hole 111, the other end face of the middle pump cover 2 is provided with a spigot feature matched with the end face 15, the middle pump cover 2 is provided with a countersunk connecting hole with the same center circle as the rear cover hole 151, one end face of the tail cover 6 is provided with a spigot feature matched with the end face 15, and the tail cover 6 is provided with a connecting hole with the same center circle as the rear cover hole 151; the end connecting disc 11 is connected with the end cover 5 or the middle pump cover 2, and the end surface 15 is connected with the tail cover 6 or the middle pump cover 2;

the middle pump cover 2 plays a role in connection, the end face 15 of one pump body 1 and the end connecting disc 11 of the other pump body 1 are respectively connected to two sides between the two pump bodies 1, the pump bodies 1 are cast parts, so that the structure with some precise sizes is inconvenient to process, after the middle pump cover 2 is added, the middle pump cover 2 is a flat full-machined workpiece, a plurality of structures can be manufactured on the end face of the middle pump cover 2 so as to meet the corresponding design requirements, for example, the end face of one end connected with the end face 15 can be provided with a plurality of spiral grooves, then the back of the impeller 3 is provided with auxiliary blades, compared with the simple auxiliary blades, better axial force balance can be realized, for example, a seal or a bearing can be arranged at the central position of the middle pump cover 2, the seal is used for blocking leakage between the two pump bodies 1, when the sections of the pump bodies 1 are more, the pump shaft 4 can be reliably supported by the, when the middle pump cover 2 plays a bearing role, the middle pump cover needs to be connected with the pump bodies 1 on two sides respectively, so that the middle pump cover needs to be connected with the pump bodies 1 on two sides respectively through fasteners, the structural design needs to be noticed, interference positions are avoided, countersunk holes are used for connection, the heads of screws are accommodated, and the axial size is saved.

The end connection disc side of the first stage pump body 1 needs to be sealed by a pump cover with a central non-opening, namely an end cover 5, while the end surface 15 side of the last stage pump body 1 needs to be connected by a pump cover with a certain axial length, namely a tail cover 6,

as shown in fig. 1 and 3, the pump shaft 4 includes a main section 41, a threaded section 42 and a transmission head 43, the main section 41 is provided with a key slot, the main section 41 is sleeved with the impeller 3, the main section 41 and the impeller 3 are in transmission through a key or a spline, one end of the main section 41 is provided with the threaded section 42, one end of the threaded section 42, which is away from the main section 41, is provided with the transmission head 43, one end of the main section 41, which is away from the threaded section 42, is provided with a transmission hole 411, the transmission hole 411 and the transmission head 43 are in a shape of being embedded or threaded, an impeller nut 91 is screwed on the threaded section 42 and abuts against a hub end of the impeller 3, and the pump; the rear part of the tail cover 6 is connected with a connecting frame used as a motor or a mounting frame connected with the motor,

a mechanical seal 94 is arranged in the tail cover 6, and the mechanical seal 94 seals one end of the pump shaft 4 extending into the tail cover 6; the pump shaft 4 is sleeved with a shaft sleeve 92, and one end of the shaft sleeve 92 abuts against the end part of the hub on the back of the impeller 3. The mechanical seal in the tail cover 6 plays a role of shaft face dynamic seal, the leakage requirement is very high due to the chemical pump, the mechanical seal 94 is used as a sealing element, the mechanical seal 94 in the tail cover 6 needs to be flushed according to the requirements of API610 and 682 according to the use occasion and the working condition, and the dynamic seal positions between the pump bodies 1 of a plurality of stages are arranged in the pump, so if the pump bodies pumping the same medium are used in an overlapping mode, only the basic mechanical seal or labyrinth rings, piston type seals and other modes are needed, interstage leakage does not leak out of the pump, and therefore the sealing requirement is not high.

Bushings 92 are used to adjust the axial spacing of the various components on the various interstage rotors.

As shown in fig. 8, the chemical pump further includes an end shaft 7 and a bearing 8, wherein one end of the end shaft 7 is provided with a blind transmission hole connected with the transmission head 43, and the other end of the end shaft 7 is mounted in the center of the end cover 5 through the bearing 8.

The pump shaft 4 needs to be axially positioned at the position of the primary pump body 1, the end shaft 7 is sleeved at the end part of the pump shaft 4 embedded in the primary pump body 1 and then installed in a bearing 8 arranged in the end cover 5, and the shaft shoulder of the end shaft 7 or a positioning structure on the shaft shoulder abuts against an inner ring of the bearing 8 to be axially positioned. Not only the axial positioning is finished, but also the effect of rotary support can be achieved, so that the pump shaft 4 is of a double-end support structure.

As shown in fig. 3, the transmission head 43 is a square cylinder, the transmission hole 411 is a blind hole with a square cross section, and the transmission head 43 and the transmission hole 411 are connected in a straight-inserting manner.

The transmission head 43 and the transmission hole 411 are directly connected, so that the installation is more convenient, only the insertion and the end part abutting against are needed, and the axial locking of the pump shafts 4 is inwards pressed through the two ends.

As shown in fig. 3, after the two pump shafts 4 are butted, a gasket 93 is fitted at the butted portion. Since there may be machining errors in the length of the pump shaft 4 and the axial length of the pump body 1, it is necessary to adjust the axial distance in order to prevent accumulation of errors. A plurality of spacers 93 of different thicknesses are backed up in advance and are inserted between the shafts when a new single stage pump head is installed.

As shown in fig. 1 and 4, a mechanical seal 94 is provided at the center of the intermediate pump cover 2. The middle pump cover 2 between the pump stages is centrally provided with a mechanical seal 94 to prevent the medium from streaming between the stages.

When a plurality of pump bodies 1 are overlapped, the inlet and the outlet of each stage of pump body 1 are connected in series. The pump body 1 can be used in parallel or in series to obtain high lift.

As shown in fig. 4, the diameter of the center circle of the rear cover hole 151 is larger than that of the end hole 111; the outer edge of the end connecting disc 11 is provided with a yielding groove 112, and the radial distance between the groove bottom of the yielding groove 112 and the pump shaft 4 is smaller than the radius of a central circle of the rear cover hole 151. The arrangement mode of the mounting holes is that in the consideration of the dismounting direction, the abdicating groove 112 is arranged on the end connecting disc 11, namely the middle pump cover 2 is connected with the end face 15 at the back and is connected with the end connecting disc 11 of the other pump body 1 at the front, during mounting, the middle pump cover 2 is firstly mounted on the end connecting disc 11 through a fastener, during dismounting, the connecting screws of the middle pump cover 2 and the end face 15 are firstly dismounted, then the upper-level pump body 1 is separated from the middle pump cover 2, the dismounting sequence can conveniently and directly reach the position of the pump cavity, and the dismounting of the pump body 1 and the impeller 3 can be completed only by dismounting once.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides a take in the axle division just to tear chemical pump of structure open which characterized in that: the chemical pump comprises a pump body (1), an impeller (3) and a pump shaft (4), wherein the pump body (1) is a side-suction side-outlet type pump body, the pump body (1) comprises an end connecting disc (11), a suction chamber (12), an impeller chamber (13), a water outlet (14) and an end face (15), the suction chamber (12) is closely adjacent to the impeller chamber (13), the end connecting disc (11) is arranged on one side of the suction chamber (12) departing from the impeller chamber (13), the end face (15) is arranged on one side of the impeller chamber (13) departing from the suction chamber (12), the water inlet is arranged on the side face of the suction chamber (12), the water outlet (14) is arranged on the side face of the impeller chamber (13), through holes are formed in the end face (15) and the end connecting disc (11) and are communicated with the suction chamber (12) and the impeller chamber (13), the diameter of the through holes in the end face (15) is larger than the outer, the impeller (3) is arranged in the impeller chamber (13);

the chemical pump also comprises an intermediate pump cover (2), an end cover (5), a tail cover (6), an impeller nut (91), a shaft sleeve (92) and a mechanical seal (94), wherein an end hole (111) for connection is formed in the end connecting disc (11), a rear cover hole (151) for connection is formed in the end face (15), one end face of the end cover (5) has a matched spigot characteristic with the end connecting disc (11), a connecting hole which has the same central circle as the end hole (111) is formed in the end cover (5), one end face of the intermediate pump cover (2) is provided with a spigot characteristic matched with the end connecting disc (11), a countersunk head connecting hole which has the same central circle as the end hole (111) is formed in the intermediate pump cover (2), the other end face of the intermediate pump cover (2) is provided with a spigot characteristic matched with the end face (15), and a countersunk head connecting hole which has the same central circle as the rear cover hole (151) is formed in the intermediate pump cover (2), the end face of one end of the tail cover (6) is provided with a spigot characteristic matched with the end face (15), and the tail cover (6) is provided with a connecting hole which has the same central circle with the rear cover hole (151); the end connecting disc (11) is connected with the end cover (5) or the middle pump cover (2), and the end face (15) is connected with the tail cover (6) or the middle pump cover (2);

the pump shaft (4) comprises a main section (41), a threaded section (42) and a transmission head (43), wherein a key groove is formed in the main section (41), an impeller (3) is sleeved on the main section (41), the main section (41) and the impeller (3) are in transmission through keys or splines, the threaded section (42) is arranged at one end of the main section (41), the transmission head (43) is arranged at one end, deviating from the main section (41), of the threaded section (42), a transmission hole (411) is arranged at one end, deviating from the threaded section (42), of the main section (41), the transmission hole (411) and the transmission head (43) are in embedded or threaded connection, an impeller nut (91) is screwed on the threaded section (42) and abuts against the end portion of a hub of the impeller (3), and the pump shaft (4) is connected with a motor from the rear of a tail cover (6);

a mechanical seal (94) is arranged in the tail cover (6), and the mechanical seal (94) seals one end of the pump shaft (4) extending into the tail cover (6); a shaft sleeve (92) is sleeved on the pump shaft (4), and one end of the shaft sleeve (92) abuts against the end part of a hub on the back of the impeller (3).

2. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: the chemical pump further comprises an end shaft (7) and a bearing (8), wherein one end of the end shaft (7) is provided with a transmission blind hole connected with a transmission head (43), and the other end of the end shaft (7) is installed in the center of the end cover (5) through the bearing (8).

3. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: the transmission head (43) is a square cylinder, the transmission hole (411) is a blind hole with a square cross section, and the transmission head (43) is directly connected with the transmission hole (411) in an inserting mode.

4. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: after the two pump shafts (4) are in butt joint, a gasket (93) is padded at the butt joint position.

5. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: and a mechanical seal (94) is arranged at the central position of the middle pump cover (2).

6. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: when a plurality of the pump bodies (1) are overlapped, the inlet and the outlet of each stage of the pump body (1) are connected in series.

7. The chemical pump with the structure of being separated from the shaft and being convenient to disassemble as claimed in claim 1, wherein: the central circle diameter of back lid hole (151) is greater than the central circle diameter of end hole (111), the outer fringe department of end connection dish (11) is equipped with and steps down groove (112), the radial distance of groove (112) tank bottom department of stepping down and pump shaft (4) is less than the central circle radius of back lid hole (151).