阅读说明：本技术 一种端吸泵 (End suction pump ) 是由 张静静 耿永红 于 2021-01-26 设计创作，主要内容包括：本发明公开了一种端吸泵,包括中间泵体,所述中间泵体的左端转动连接有左泵体、右端转动连接有右泵体,中间泵腔内转动连接有中间轴套,左泵腔内转动连接左轴套,右泵腔内转动连接有右轴套,所述左轴套、中间轴套、右轴套内设有动力轴；所述中间轴套设有中间叶轮,所述左轴套设有左叶轮,所述右轴套设有右叶轮；所述中间泵体的外侧设有进液口,所述左泵体的外侧设有增压出口,所述右泵体的外侧设有增流出口；所述中间泵体的两侧设有第一电动推杆,两个第一电动推杆的伸缩端设有切换组件；该端吸泵不仅结构简单,而且可以根据需要在低压大流量或者高压小流量之间切换。(The invention discloses an end suction pump, which comprises a middle pump body, wherein the left end of the middle pump body is rotatably connected with a left pump body, the right end of the middle pump body is rotatably connected with a right pump body, a middle shaft sleeve is rotatably connected in a middle pump cavity, a left shaft sleeve is rotatably connected in the left pump cavity, a right shaft sleeve is rotatably connected in the right pump cavity, and power shafts are arranged in the left shaft sleeve, the middle shaft sleeve and the right shaft sleeve; the middle shaft sleeve is provided with a middle impeller, the left shaft sleeve is provided with a left impeller, and the right shaft sleeve is provided with a right impeller; a liquid inlet is formed in the outer side of the middle pump body, a pressurizing outlet is formed in the outer side of the left pump body, and a flow increasing outlet is formed in the outer side of the right pump body; the two sides of the middle pump body are provided with first electric push rods, and the telescopic ends of the two first electric push rods are provided with switching assemblies; the end suction pump is simple in structure and can be switched between low-pressure large flow or high-pressure small flow according to requirements.)

1. A kind of end suction pump, characterized by, including the middle pump body, the left end of the said middle pump body rotates and connects with the left pump body, the right end rotates and connects with the right pump body, there is middle pump cavity in the said middle pump body, there is left pump cavity in the said left pump body, there is right pump cavity in the said right pump body, the said middle pump cavity internal rotation connects with the middle axle sleeve, the said left pump cavity internal rotation connects with the coaxial left axle sleeve of middle axle sleeve, the said right pump cavity internal rotation connects with the coaxial right axle sleeve of middle axle sleeve, there are power shafts in said left axle sleeve, middle axle sleeve, right axle; the outer side of the middle shaft sleeve is fixedly provided with a middle impeller positioned in a middle pump cavity, the outer side of the left shaft sleeve is fixedly provided with a left impeller positioned in a left pump cavity, and the outer side of the right shaft sleeve is fixedly provided with a right impeller positioned in a right pump cavity; a liquid inlet is formed in the outer side of the middle pump body, a pressurizing outlet is formed in the outer side of the left pump body, and a flow increasing outlet is formed in the outer side of the right pump body; a left inlet and a left outlet communicated with the supercharging outlet are arranged in the left pump body, and a right inlet and a right outlet communicated with the flow increasing outlet are arranged in the right pump body; a liquid outlet hole and a middle inlet hole communicated with the liquid inlet are formed in the middle pump body; the front side and the rear side of the middle pump body are respectively and fixedly provided with a first electric push rod along the left-right direction, the telescopic ends of the two first electric push rods are provided with a switching component connected with the left pump body and the right pump body, when the first electric push rods are completely extended out, the switching components control the left pump body and the right pump body to rotate to a first position, the liquid outlet hole is communicated with the left inlet, the liquid outlet hole is disconnected with the right outlet, and the right inlet is disconnected with the middle inlet; when first electric putter contracts completely, switching module control left pump body and right pump body all rotate to the second position, go out liquid hole and left import disconnection, go out liquid hole and right export intercommunication, right import and middle import intercommunication.

2. The end suction pump of claim 1, wherein the switching assembly comprises a cross bar fixedly connected between two telescopic ends of the first electric push rod, a driving rod is arranged at the front end of the cross bar along the left-right direction, a left chute is arranged on the outer side of the circumference of the left pump body, a right chute is arranged on the outer side of the circumference of the right pump body, a left convex column extending into the left chute and a right convex column extending into the right chute are arranged on the outer side of the driving rod; when the first electric push rod is completely extended, the left pump body and the right pump body rotate to the first position under the action of the left convex column and the left chute and the action of the right convex column and the right chute; when the first electric push rod is completely contracted, the left pump body and the right pump body are rotated to the second position under the action of the left convex column and the left chute and the action of the right convex column and the right chute.

3. The end suction pump of claim 2, wherein the inner bore side wall of the left hub is provided with a left positioning groove, the inner bore side wall of the middle hub is provided with a middle positioning groove, and the inner bore side wall of the right hub is provided with a right positioning groove; a left sliding block assembly, a middle sliding block assembly and a right sliding block assembly are sequentially arranged in the power shaft from left to right, when the first electric push rod is completely extended out, the left sliding block assembly is matched with the left positioning groove, the middle sliding block assembly is matched with the second middle positioning groove, the right sliding block assembly is separated from the right positioning groove, and the left shaft sleeve and the middle shaft sleeve are driven to synchronously rotate when the power shaft rotates; when first electric putter contracts completely, right slider component and right constant head tank cooperation, middle slider component and the cooperation of constant head tank in the middle of the second, left slider component and left constant head tank break away from the cooperation, and drive right axle sleeve and middle axle sleeve synchronous rotation when the power shaft rotates.

4. The end suction pump of claim 3, wherein a shaft hole with an open left end is arranged in the power shaft, a push rod connected with the cross rod is arranged in the shaft hole, the left end of the push rod penetrates out of the cross rod, the push rod is provided with a left shoulder on the left side of the cross rod, a right shoulder on the right side of the cross rod, a left spring is arranged between the left shoulder and the cross rod on the outer side of the push rod, and a right spring is arranged between the right shoulder and the cross rod; the outer side of the ejector rod is provided with a large-diameter section which is connected in the shaft hole in a sliding manner.

5. The end suction pump as claimed in claim 4, wherein the left slider assembly, the middle slider assembly and the right slider assembly have the same structure and comprise a limiting block, a radial sliding groove communicated with the shaft hole is radially arranged in the power shaft, the limiting block is radially and slidably connected in the radial sliding groove, notches are formed in the radial sliding groove at the outer side of the power shaft, limiting lugs extending out of the notches are arranged on the limiting block, and a first spring for forcing the limiting lugs to retract into the notches is arranged in each radial sliding groove; the left side and the right side of each limiting block are provided with first chamfers; when the first electric push rod is completely extended out, the large-diameter section of the push rod pushes out the limiting lugs in the left slider component and the middle slider component and respectively extends into the left positioning groove and the middle positioning groove, and the limiting lug in the right slider component retracts into the notch to be separated from the right positioning groove under the action of the first spring; when the first electric push rod is completely contracted, the large-diameter section of the push rod pushes out the limiting convex blocks in the right sliding block assembly and the middle sliding block assembly to respectively extend into the right positioning groove and the middle positioning groove, and the limiting convex block in the left sliding block assembly retracts into the notch to be separated from the left positioning groove under the action of the first spring.

Technical Field

The invention relates to the field of fluid machinery, in particular to an end suction pump.

Background

The inlet of the end-suction centrifugal pump is vertical to the direction of the impeller, and the inlet is positioned at one end of the side surface of the impeller. The end suction centrifugal pump is applied to the transportation of industrial liquid, urban water supply and drainage, pressurized water supply for high-rise buildings, garden sprinkling irrigation, fire control pressurization, heating and other cold and hot water circulating pressurization and equipment matching, the circulation of an air conditioning unit, the transportation of cooling water and the like;

the end suction centrifugal pump can meet the working condition that low pressure and large flow or high pressure and small flow are needed in the actual use process, and the centrifugal pump which can simultaneously meet the requirements of the working conditions does not exist in the prior art.

Disclosure of Invention

The invention aims to provide an end suction pump which is simple in structure and can be switched between low-pressure large flow or high-pressure small flow according to requirements.

In order to achieve the purpose, the invention provides the following technical scheme: a kind of end suction pump, including the middle pump body, the left end of the said middle pump body rotates and connects with the left pump body, the right end rotates and connects with the right pump body, there is middle pump cavity in the said middle pump body, there is left pump cavity in the said left pump body, there is right pump cavity in the said right pump body, the said middle pump cavity rotates and connects with the middle axle sleeve, the said left pump cavity rotates and connects with the left axle sleeve coaxial with middle axle sleeve, the said right pump cavity rotates and connects with the right axle sleeve coaxial with middle axle sleeve, there are power shafts in said left axle sleeve, middle axle sleeve, right; the outer side of the middle shaft sleeve is fixedly provided with a middle impeller positioned in a middle pump cavity, the outer side of the left shaft sleeve is fixedly provided with a left impeller positioned in a left pump cavity, and the outer side of the right shaft sleeve is fixedly provided with a right impeller positioned in a right pump cavity; a liquid inlet is formed in the outer side of the middle pump body, a pressurizing outlet is formed in the outer side of the left pump body, and a flow increasing outlet is formed in the outer side of the right pump body; a left inlet and a left outlet communicated with the supercharging outlet are arranged in the left pump body, and a right inlet and a right outlet communicated with the flow increasing outlet are arranged in the right pump body; a liquid outlet hole and a middle inlet hole communicated with the liquid inlet are formed in the middle pump body; the front side and the rear side of the middle pump body are respectively and fixedly provided with a first electric push rod along the left-right direction, the telescopic ends of the two first electric push rods are provided with a switching component connected with the left pump body and the right pump body, when the first electric push rods are completely extended out, the switching components control the left pump body and the right pump body to rotate to a first position, the liquid outlet hole is communicated with the left inlet, the liquid outlet hole is disconnected with the right outlet, and the right inlet is disconnected with the middle inlet; when first electric putter contracts completely, switching module control left pump body and right pump body all rotate to the second position, go out liquid hole and left import disconnection, go out liquid hole and right export intercommunication, right import and middle import intercommunication.

Furthermore, the switching assembly comprises a cross rod fixedly connected between the telescopic ends of the two first electric push rods, a driving rod is arranged at the front end of the cross rod along the left-right direction, a left chute is arranged on the outer side of the circumference of the left pump body, a right chute is arranged on the outer side of the circumference of the right pump body, and a left convex column extending into the left chute and a right convex column extending into the right chute are arranged on the outer side of the driving rod; when the first electric push rod is completely extended, the left pump body and the right pump body rotate to the first position under the action of the left convex column and the left chute and the action of the right convex column and the right chute; when the first electric push rod is completely contracted, the left pump body and the right pump body are rotated to the second position under the action of the left convex column and the left chute and the action of the right convex column and the right chute.

Furthermore, a left positioning groove is formed in the side wall of the inner hole of the left shaft sleeve, a middle positioning groove is formed in the side wall of the inner hole of the middle shaft sleeve, and a right positioning groove is formed in the side wall of the inner hole of the right shaft sleeve; a left sliding block assembly, a middle sliding block assembly and a right sliding block assembly are sequentially arranged in the power shaft from left to right, when the first electric push rod is completely extended out, the left sliding block assembly is matched with the left positioning groove, the middle sliding block assembly is matched with the second middle positioning groove, the right sliding block assembly is separated from the right positioning groove, and the left shaft sleeve and the middle shaft sleeve are driven to synchronously rotate when the power shaft rotates; when first electric putter contracts completely, right slider component and right constant head tank cooperation, middle slider component and the cooperation of constant head tank in the middle of the second, left slider component and left constant head tank break away from the cooperation, and drive right axle sleeve and middle axle sleeve synchronous rotation when the power shaft rotates.

Furthermore, a shaft hole with an open left end is formed in the power shaft, a push rod connected with the cross rod is arranged in the shaft hole, the left end of the push rod penetrates out of the cross rod, a left convex shoulder is arranged on the left side of the cross rod of the push rod, a right convex shoulder is arranged on the right side of the cross rod, a left spring is arranged between the left convex shoulder and the cross rod on the outer side of the push rod, and a right spring is arranged between the right convex shoulder and the cross rod; the outer side of the ejector rod is provided with a large-diameter section which is connected in the shaft hole in a sliding manner.

Furthermore, the left slider assembly, the middle slider assembly and the right slider assembly have the same structure and respectively comprise a limiting block, a radial sliding groove communicated with the shaft hole is formed in the power shaft along the radial direction, the limiting blocks are connected in the radial sliding groove in a sliding manner along the radial direction, notches are formed in the radial sliding groove on the outer side of the power shaft, limiting lugs extending out of the notches are arranged on the limiting blocks, and a first spring used for forcing the limiting lugs to retract into the notches is arranged in each radial sliding groove; the left side and the right side of each limiting block are provided with first chamfers; when the first electric push rod is completely extended out, the large-diameter section of the push rod pushes out the limiting lugs in the left slider component and the middle slider component and respectively extends into the left positioning groove and the middle positioning groove, and the limiting lug in the right slider component retracts into the notch to be separated from the right positioning groove under the action of the first spring; when the first electric push rod is completely contracted, the large-diameter section of the push rod pushes out the limiting convex blocks in the right sliding block assembly and the middle sliding block assembly to respectively extend into the right positioning groove and the middle positioning groove, and the limiting convex block in the left sliding block assembly retracts into the notch to be separated from the left positioning groove under the action of the first spring.

Advantageous effects

Compared with the prior art, the technical scheme of the invention has the following advantages:

1. the first electric push rod stretches and retracts to control the ejector rod to move, so that the connection or disconnection of the power shaft and the left shaft sleeve, the middle shaft sleeve and the right shaft sleeve is changed, the working states of the left impeller, the middle impeller and the right impeller are changed, and the switching pressurization or flow increase working state of the centrifugal pump is achieved;

2. the power rod fixed on the cross rod controls the rotation of the left pump body and the right pump body, so that the first electric push rod can stretch and retract and simultaneously drive the left pump body and the right pump body to rotate to change a flow channel, thereby being suitable for different working conditions and achieving the effect of saving energy;

3. the first chamfers are arranged on the two sides of the limiting block, so that the limiting block can be conveniently pushed out when the large-diameter section of the ejector rod moves;

4. the limiting convex block is reset through the first spring, and the first spring withdraws the limiting convex block when the large-diameter section leaves the limiting block.

Drawings

FIG. 1 is a front view of the present invention in a state of increasing end suction pump pressure;

FIG. 2 is a side view of the present invention in a state of increasing end suction pump pressure;

FIG. 3 is a sectional view taken along line A-A of FIG. 2 in accordance with the present invention;

FIG. 4 is a sectional view taken along line B-B of FIG. 3 according to the present invention

FIG. 5 is a cross-sectional view taken along line C-C of FIG. 3 in accordance with the present invention;

FIG. 6 is an elevational view of the present invention in a state of increasing end suction pump flow;

FIG. 7 is a side view of the present invention in a state of increasing end suction pump flow;

FIG. 8 is a cross-sectional view taken along line D-D of FIG. 7 in accordance with the present invention;

FIG. 9 is a cross-sectional view taken in the direction E-E of FIG. 8 in accordance with the present invention;

fig. 10 is a partial view of the area I of fig. 9 in accordance with the present invention.

Detailed Description

Referring to fig. 1-10, a suction end pump includes a middle pump body 22, a left pump body 21 is rotatably connected to a left end of the middle pump body 22, a right pump body 23 is rotatably connected to a right end of the middle pump body 22, a middle pump cavity 2b is arranged in the middle pump body 22, a left pump cavity 2a is arranged in the left pump body 21, a right pump cavity 2c is arranged in the right pump body 23, a middle shaft sleeve 17 is rotatably connected to the middle pump cavity 2b, a left shaft sleeve 15 coaxial with the middle shaft sleeve 17 is rotatably connected to the left pump cavity 2a, a right shaft sleeve 18 coaxial with the middle shaft sleeve 17 is rotatably connected to the right pump cavity 2c, and a power shaft 14 is arranged in the left shaft sleeve 15, the middle shaft sleeve; the outer side of the middle shaft sleeve 17 is fixedly provided with a middle impeller 221 positioned in the middle pump cavity 2b, the outer side of the left shaft sleeve 15 is fixedly provided with a left impeller 211 positioned in the left pump cavity 2a, and the outer side of the right shaft sleeve 18 is fixedly provided with a right impeller 231 positioned in the right pump cavity 2 c; a liquid inlet 22a is formed in the outer side of the middle pump body 22, a pressurizing outlet 21a is formed in the outer side of the left pump body 21, and a flow increasing outlet 23a is formed in the outer side of the right pump body 23; a left inlet 213 and a left outlet 212 communicated with the pressurization outlet 21a are arranged in the left pump body 21, and a right inlet 233 and a right outlet 232 communicated with the flow increasing outlet 23a are arranged in the right pump body 23; a liquid outlet hole 222 and a middle inlet hole 223 communicated with the liquid inlet 22a are formed in the middle pump body 22; the front side and the rear side of the middle pump body 22 are fixedly provided with first electric push rods 11 along the left-right direction, the telescopic ends of the two first electric push rods 11 are provided with switching components connected with the left pump body 21 and the right pump body 23, when the first electric push rods 11 are completely extended out, the switching components control the left pump body 21 and the right pump body 23 to rotate to the first positions, the liquid outlet hole 222 is communicated with the left inlet 213, the liquid outlet hole 222 is disconnected with the right outlet 232, and the right inlet 233 is disconnected with the middle inlet; when the first electric push rod 11 is completely retracted, the switching assembly controls the left pump body 21 and the right pump body 23 to rotate to the second position, the liquid outlet hole 222 is disconnected from the left inlet 213, the liquid outlet hole 222 is communicated with the right outlet 232, and the right inlet 233 is communicated with the middle inlet.

The switching assembly comprises a cross rod 12 fixedly connected between the telescopic ends of two first electric push rods 11, a driving rod 121 is arranged at the front end of the cross rod 12 along the left-right direction, a left chute 214 is arranged on the outer side of the circumference of the left pump body 21, a right chute 234 is arranged on the outer side of the circumference of the right pump body 23, and a left convex column 1211 extending into the left chute 214 and a right convex column 1212 extending into the right chute 234 are arranged on the outer side of the driving rod 121; when the first electric push rod 11 is fully extended, the left pump body 21 and the right pump body 23 both rotate to the first position under the action of the left convex column 1211 and the left chute 214 and the action of the right convex column 1212 and the right chute 234; when the first electric putter 11 is fully retracted, the left pump body 21 and the right pump body 23 rotate to the second position under the actions of the left protruding pillar 1211 and the left inclined groove 214, and the right protruding pillar 1212 and the right inclined groove 234.

A left positioning groove 15a is formed in the side wall of an inner hole of the left shaft sleeve 15, a middle positioning groove 17a is formed in the side wall of the inner hole of the middle shaft sleeve 17, and a right positioning groove 18a is formed in the side wall of the inner hole of the right shaft sleeve 18; a left sliding block assembly, a middle sliding block assembly and a right sliding block assembly are sequentially arranged in the power shaft 14 from left to right, when the first electric push rod 11 is completely extended out, the left sliding block assembly is matched with the left positioning groove 15a, the middle sliding block assembly is matched with the second middle positioning groove 17a, the right sliding block assembly is separated from the right positioning groove 18a, and the power shaft 14 drives the left shaft sleeve 15 and the middle shaft sleeve 17 to synchronously rotate when rotating; when the first electric push rod 11 is completely contracted, the right slider component is matched with the right positioning groove 18a, the middle slider component is matched with the first middle positioning groove 17a, the left slider component is separated from the left positioning groove 15a, and the power shaft 14 drives the right shaft sleeve 18 and the middle shaft sleeve 17 to synchronously rotate when rotating.

In this embodiment, a shaft hole 14a with an open left end is formed in the power shaft 14, a push rod 13 connected with the cross rod 12 is arranged in the shaft hole 14a, the left end of the push rod 13 penetrates through the cross rod 12, a left shoulder 13a is arranged on the left side of the cross rod 12 of the push rod 13, a right shoulder 13b is arranged on the right side of the cross rod 12, a left spring 131 is arranged between the left shoulder 13a and the cross rod 12 on the outer side of the push rod 13, and a right spring 132 is arranged between the right shoulder 13b and the cross rod 12; the outer side of the top rod 13 is provided with a large-diameter section 133 which is connected in the shaft hole 14a in a sliding way. The left slider assembly, the middle slider assembly and the right slider assembly have the same structure and respectively comprise a limiting block 16, a radial sliding groove 14a communicated with the shaft hole 14a is radially arranged in the power shaft 14, the limiting blocks 16 are connected in the radial sliding groove 14a in a sliding manner along the radial direction, notches 14b are respectively arranged at the radial sliding grooves 14a at the outer side of the power shaft 14, limiting lugs 161 extending out of the notches 14b are respectively arranged on the limiting blocks 16, and a first spring 19 for forcing the limiting lugs 161 to retract into the notches 14b is respectively arranged in each radial sliding groove 14 a; the left side and the right side of each limiting block 16 are provided with first chamfers 16 a; when the first electric push rod 11 is completely extended, the large-diameter section 133 of the push rod 13 pushes the limit lugs 161 in the left slider component and the middle slider component out to respectively extend into the left positioning groove 15a and the middle positioning groove 17a, and the limit lug 161 in the right slider component retracts into the notch 14b and is separated from the right positioning groove 18a under the action of the first spring 19; when the first electric push rod 11 is completely contracted, the large-diameter section 133 of the push rod 13 pushes out the limiting lugs 161 in the right slider assembly and the middle slider assembly to respectively extend into the right positioning groove 18a and the middle positioning groove 17a, and the limiting lugs 161 in the left slider assembly are retracted into the notch 14b and separated from the left positioning groove 15a under the action of the first spring 19.

When the flow increasing working state is realized, the first electric push rod 11 is in the fully retracted position, as shown in fig. 8, at this time, the left pump body 21 and the right pump body 23 both rotate to the second position; the middle inlet 223 and the right inlet 233 are communicated with the liquid inlet 22a, the liquid outlet 222 and the right outlet 232 are communicated with the flow increasing outlet 23a, when the centrifugal pump works, the power shaft 14 rotates, because the large diameter section 133 of the mandril 13 pushes the limit lug 161 in the middle slider assembly and the right slider assembly out of the power shaft 14, the middle shaft sleeve 17, the right shaft sleeve 18 and the power shaft 14 are engaged, because the left limit lug 161 in the left slider assembly retracts into the notch 14b under the action of the first spring 19 to be disconnected with the left shaft sleeve 15, and because the middle shaft sleeve 17 and the middle impeller 221 are fixedly connected, the right shaft sleeve 18 and the right impeller 231 are fixedly connected, the power shaft 14 rotates to drive the middle impeller 221 and the right impeller 231 to rotate at the same time, so that liquid can be sucked from the liquid inlet 22a through the middle impeller 221 and the right impeller 231, the liquid can be acted through the middle impeller 221 and the right impeller 231, and then is pumped from the liquid outlet 222 and the right outlet 232 to the flow increasing outlet 23a (, the end suction pump is in a flow increasing working state.

When the invention is controlled to be switched to a pressurization working state, the first electric push rod 11 is started to extend, because the telescopic end of the first electric push rod 11 is fixedly connected with the cross rod 12, and the cross rod 12 is in sliding connection with the ejector rod 13 through the left spring 131, the right spring 132, the left spring 131 and the right spring 132 are arranged to provide buffering when the first electric push rod 11 extends and contracts; when the first electric push rod 11 extends out, the driving rod 121 is matched with the left chute 214 through the left convex column 1211, the right convex column 1212 is matched with the right chute 234, the left pump body 21 and the right pump body 23 are driven to rotate to change the flow channel, at this time, the middle inlet hole 223 is communicated with the liquid inlet 22a, the liquid outlet hole 222 is communicated with the left inlet 213, the left outlet 212 is communicated with the pressurization outlet 21a, meanwhile, the ejector rod 13 drives the large-diameter section 133 to start to move left, the left spring 131 and the right spring 132 deform under the action of the ejector rod 13 and the cross rod 12 to generate a force which forces the ejector rod 13 to drive the large-diameter section 133 to extend left, when the position-limiting convex block 161 in the left slider assembly is matched with the position of the left positioning groove 15a due to the continuous rotation of the power shaft 14, the large-diameter section 133 of the ejector rod 13 pushes the position-limiting convex block 161 in the left slider assembly out of the notch 14 and extends into the left positioning, the limit bump 161 in the right slider assembly is retracted into the power shaft 14 under the action of the first spring 19, the power shaft 14 rotates and drives the left impeller 211 and the middle impeller 221 to rotate, so that liquid can be sucked from the liquid inlet 22a through the middle impeller 221, the liquid enters the left inlet 213 from the liquid outlet 222, is pressurized by the left impeller 211, and is then pumped from the left outlet 212 to the pressurization outlet 21a (as shown in fig. 3), and at this time, the end-suction pump pressurization operation state is achieved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.