KR200467220Y1

KR200467220Y1 - Plunger pump

Info

Publication number: KR200467220Y1
Application number: KR2020120010362U
Authority: KR
Inventors: 김영윤
Original assignee: 김영윤
Priority date: 2012-11-13
Filing date: 2012-11-13
Publication date: 2013-06-04

Abstract

Durable plunger pump according to the present invention
More specifically, the head 23 of the plunger 20 has a bottom dead center for fluid discharge so that the contact surface due to the pumping motion of the plunger 20 can be easily broken and the life of the pump is shortened. In contact with the bottom surface of the pumping space 11 of the first cylinder 10, the pressing portion 25 of the plunger 20 is in contact with the upper end 113 of the pumping space of the first cylinder (10). It is characterized by.
The plunger pump having improved durability includes a first cylinder 10 having a pumping space 11 and having a suction part 13 and a discharge part 15; Coupled to the pumping space (11) of the first cylinder (10) for linear reciprocating motion, the body 21, the head 23 connected to one end of the body 21, and is provided at the other end of the body 21 A plunger 20 having a pressurizing portion 25; A coupling part coupled to the first cylinder 10, covering the pumping space 11 of the first cylinder 10, and providing a lifting space 31 in which the pressing part 25 of the plunger 20 moves. Two cylinders 30; And operating means connecting valves 40a and 40b for supplying a working fluid to the upper and lower portions of the pressurizing portion 25 of the plunger 20 to move the plunger 20. .

Description

Durable plunger pump {PLUNGER PUMP}

The present invention relates to an improved plunger pump,

More specifically, a pump having a pumping space, comprising a cylinder having a suction part and a discharge part, and a plunger that vertically moves the pumping space, and discharges the fluid introduced due to the pumping motion of the plunger,

The head of the plunger contacts the bottom of the pumping space of the first cylinder at the bottom dead center position for fluid discharge so that the contact surface due to the pumping motion of the plunger is easily broken and the life of the pump is shortened. The pressurizing portion of the plunger relates to an improved plunger pump, characterized in that it is in contact with the upper end of the pumping space of the first cylinder.

Patent Publication No. 10-2004-0043952 "Pneumatic cylinder for wafer transfer having a buffer means" corresponding to a conventional plunger pump with improved durability,

According to the above-mentioned patent, a stage mounted on the upper surface and a plurality of lift pins are installed up and down; A pneumatic cylinder connected to the lift pin by the connector to up and down the lift pin; The pneumatic cylinder has a predetermined space and the cylinder body having a first and second air inlet on one side and the other side; A front base cap and a rear base cap respectively installed at both ends of the cylinder body, each having a front through hole and a rear through hole; A front bearing and a rear bearing installed on one surface of the front base cap and the rear base cap and respectively installed in the cylinder body; A piston rod penetrating the front through hole and the rear through hole and installed inside the cylinder body; A front seal and a rear seal installed between the front through hole and the rear through hole and the piston rod; A piston installed on one side of the piston rod; A first o-ring installed on a surface in contact between the piston and the cylinder body; And it proposes a pneumatic cylinder including a buffer means installed on both sides in contact with the front bearing and the rear bearing on the piston moving along the piston rod.

However, the technique of the present invention, by providing a buffer means on the upper and lower sides of the piston can mitigate the minute impact caused by the upper or lower surface of the piston in contact with the front or rear bearing by the reciprocating motion of the piston, There is a problem that can not prevent the damage caused.

There is also a Patent No. 10-0865908 "Booster Pump",

In the registered patent, a housing having a valve operating space having an air supply and a drain portion and a fluid compression space having a fluid inlet and an outlet portion at an upper and a lower portion of the main operating space, a compression piston inserted into the fluid compression space, and the main operation A booster pump comprising an elevating piston shaft having an operating piston mounted in a space and a slide valve portion mounted in the valve operating space, and a connection pipe interconnecting a lower portion of the main operating space and a middle of the valve operating space. ; The slide valve portion, the valve body is formed in the valve operating space and the intermediate projection jaw formed with a plurality of recessed grooves on the outside, and formed in a corresponding position of the respective recessed grooves around the valve operating space A booster pump including a depression portion and a guide locking portion for guiding the momentary elevation of the valve body while the angle and length of the valve body are changed between the depression grooves and the depressions is provided.

However, the present invention is provided with a guide locking portion for guiding the lifting and lowering of the valve body to prevent the wear phenomenon of the periphery of the valve body and the guide locking portion, but the technique of preventing the breakage of the plunger that plays a major role of the pump Is not presented.

There is also a utility model registration No. 20-0178077 Air Drive Pump.

In the registration utility model, an air inflow path through which air of an air compressor is supplied at a predetermined pressure is formed at one side, and two inner and outer air supply paths 12 and 13 are formed to penetrate downwards on both sides, respectively. An upper body having an air compression chamber formed by a sealing cap and a packing at both ends, and an air discharge passage communicating with the air compression chamber at both upper ends thereof; A lower body having a guide hole formed on a central axis, and a discharge part through which a pumped liquid is discharged inside the lower end and penetrated to one side; An inner cylinder having an air distribution hole formed while being communicatively coupled between the upper body and the lower body and communicating with an inner air supply path of the upper body; An outer cylinder communicatively coupled between the upper body and the lower body to maintain a predetermined gap with the inner cylinder and in communication with an outer air supply path of the upper body; A lower cylinder having a foot valve in which a packing ring is fixed to an inner upper end and coupled to a lower end of the lower body, and a ball valve is installed at a lower end thereof to control the access of liquid; The upper end is located inside the inner cylinder through the packing hole and the guide hole of the lower body, a slide hole of a predetermined depth is formed from the upper end to the lower end, and an opening and closing hole is installed at the lower end to shield the packing ring. A piston rod disposed at an inner side of the lower body at an upper side of the opening and closing portion, and a piston rod coupled to the inner wall of the inner cylinder at an upper outer periphery thereof; A spool rod having a lower end portion slidable through a rod keeper at an upper end of the piston rod and slidable in a slide hole, and having an upper end portion in an air compression chamber of the upper body; A spool housing which slides a predetermined height in close contact with a plurality of sealing rings along an inner circumference of the air compression chamber of the upper body and has a ventilation hole selectively communicating with the inner and outer air supply paths of the upper body; A first spool is coalesced together with a spring at an inner circumference of the spool housing, the through-hole of the first spool extends slightly larger than the spool rod, and a second corresponding to the inner circumference of the spool housing at the upper middle of the spool rod. While fixing the spool, the air drive pump is characterized by consisting of a spool member and the like installed in the upper end of the spool housing by the third spool to be suppressed by the spring.

However, the utility model has been proposed to protect the external shock and reduce noise, there is a problem that can not prevent damage due to friction and contact inside the pump.

In addition, there is a Patent Application Publication No. 10-2011-0104773 `` lubricating oil pumping device for pottery, ''

In the above-mentioned patent, the hollow part, the compressed air supply passage and the lubricating oil to the air cylinder

A supply hole is formed, the upper end of the hollow part is sealed by a cap, the hollow part and the compressed air supply path are communicated at the upper end of the air cylinder, the hollow part and the first lubricant supply hole are communicated at the lower end of the air cylinder, The air piston and the plunger piston are disposed in the hollow portion of the cylinder, the plunger cylinder is mounted in the lower mounting hole of the air cylinder, the second lubricating oil supply hole formed in the plunger cylinder is formed, and the plunger rod portion of the plunger piston is formed. Lubricant pumping device for oiler, fitted in the hollow part of the plunger cylinder, elastically supported by the piston part of the plunger piston by a spring disposed in the hollow part of the air cylinder, and a check valve mounted in the lower mounting hole of the air cylinder. Presenting.

However, although the patent discloses a method for quantitatively pumping lubricating oil, there is no technique for preventing damage to the pumping device.

Therefore, the present invention has been made to solve the above problems, in the durability improved plunger pump, the purpose of the pumping to solve the problem of damage caused by friction and impact that the contact surface is due to the pumping of the plunger A first cylinder having a space and having a suction part and a discharge part;

It is coupled to the pumping space of the cylinder and performs a linear reciprocating motion, and includes a plunger having a body, a head connected to one end of the body, and a pressing unit provided at the other end of the body,

Coupled to the first cylinder,

A second cylinder covering the pumping space of the first cylinder and providing a lifting space in which the pressurization portion of the plunger moves;

It includes an operating means for moving the plunger by supplying a working fluid to the upper and lower pressure portion of the plunger,

The head of the plunger is in contact with the bottom of the pumping space of the first cylinder in the bottom dead center position for fluid discharge, the pressing portion of the plunger is in contact with the upper end of the pumping space of the first cylinder is improved durability It is an object to provide a plunger pump.

In order to achieve the above object, the plunger pump having improved durability according to the present invention has a pumping space, and includes a first cylinder having a suction part and a discharge part;

Coupled to the first cylinder,

A second cylinder which covers the pumping space of the first cylinder and provides a lifting space in which the pressurization portion of the plunger moves, and operating means for supplying a working fluid to the upper and lower portions of the pressurization portion of the plunger to move the plunger; ,

The head of the plunger is provided with an upper first sealing ring in contact with the inner wall of the pumping space of the first cylinder, and a lower second sealing ring, and the second sealing ring in contact with the pumping fluid first has durability or chemical resistance, Or it is characterized by being made of a material having both properties.

As described above, the plunger pump having improved durability according to the present invention includes a first cylinder having a pumping space, and having a suction part and a discharge part.

Coupled to the first cylinder,

The head of the plunger is in contact with the bottom surface of the pumping space of the first cylinder at the bottom dead center position for fluid discharge, the pressing portion of the plunger is in contact with the upper end of the pumping space of the second cylinder, plunger Minimizes the friction generated in the pumping space of the cylinder, and solves the problem of breakage caused by friction, the head of the plunger, the upper first sealing ring in contact with the inner wall of the pumping space of the first cylinder, and the lower agent The second sealing ring is provided with a sealing ring, and the second sealing ring, which first comes into contact with the pumping fluid, is made of a material having characteristics of durability or chemical resistance, or both, so that the life of the pump due to heat and impact due to plunger friction This shortening problem can be solved.

1 is a perspective view according to the present invention
2 is a cross-sectional view and an embodiment according to the present invention
3 is a cross-sectional view of the plunger according to the present invention
4 is an enlarged view of a suction part and a discharge part according to the present invention;
5 is an enlarged view of the first and second fastening portions according to the present invention;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention may be modified in various ways and may have various forms. Therefore, embodiments (or embodiments) will be described in detail in the text. It should be understood, however, that this invention is not intended to be limited to the particular forms disclosed, but is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, the same reference numerals are used for the same reference numerals, and in particular, the numerals of the tens and the digits of the digits, the digits of the tens, the digits of the digits and the alphabets are the same, Members referred to by reference numerals can be identified as members corresponding to these standards.

In the drawings, the components are expressed by exaggeratingly larger (or thicker) or smaller (or thinner) in size or thickness considering simplicity of understanding, etc. However, since the scope of protection of the present invention is limited It should not be.

The terminology used herein is for the purpose of describing particular embodiments (suns and aspects) (or embodiments) only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the term " comprising " or " consisting of ", or the like, refers to the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

In the present specification, the first to the second and the second to refer to different components, are not limited to the order of manufacture, and their names coincide in the detailed description of the invention and the claims. You can't.

In describing the plunger pump with improved durability according to the present invention, for the sake of convenience, the non-strict approximate direction reference is specified with reference to FIG. Dividing one cylinder part into lower part, and explaining by dividing it up and down, right and left, front and rear

First, as shown in FIG. 2, the plunger pump having improved durability according to the present invention includes a pumping space 11, a first cylinder 10 having a suction part 13 and a discharge part 15; Coupled to the pumping space of the first cylinder 10 to perform a linear reciprocating motion,

Of the plunger 20 and the first cylinder 10 having a body 21, a head 23 connected to one end of the body 21, and a pressing part 25 provided at the other end of the body 21. The second cylinder 30 and the pressurizing portion 25 of the plunger 20 which cover the pumping space 11 and provide a lifting space 31 in which the pressurizing portion 25 of the plunger 20 moves. It includes a working means for moving the plunger 20 by supplying a working fluid to the upper and lower,

The cap 50 including the pressure adjusting member 51 for adjusting the pumping motion of the plunger 20 by adjusting the pressure of the working fluid flowing into the operating means connecting valve 40b on the upper end of the second cylinder Combined,

The head 23 of the plunger 20 contacts the bottom surface of the pumping space 11 of the first cylinder 10 at a bottom dead center position for fluid discharge.

When the pump A operates, the plunger 20 moves up and down. At this time, the pressurization portion 25 of the plunger 20 contacts the upper end 113 of the pumping space of the first cylinder 10. It will cause abrasion and breakage, resulting in weak durability. In order to solve this problem, the material of the pressurizing portion 25 of the plunger 20 and the upper end portion 113 of the pumping space of the first cylinder 10 may be replaced with a durable material. However, these materials are expensive and have economic difficulties, which makes them unsuitable for use in pumps. Therefore, as shown in FIG. 5, the present invention provides the pressing portion 25 of the plunger 20 to be in contact with the upper portion 113 of the pumping space of the first cylinder 10 while being in contact with the pressing portion 25. It is characterized by improving the durability by eliminating the impact received by the pumping space upper end 113, thereby preventing wear and breakage.

In addition, when looking at the embodiment of the plunger pump (A) it is disposed lying sideways as shown, so that the suction portion 13 is configured to receive the force of gravity. Accordingly, the working fluid is introduced into the first valve body 131a which is disposed toward the suction part by gravity and prevents the suction of the fluid through the operation means connecting valve 40a at the bottom of the pressurizing part 25 of the plunger 20. When the pressure is applied to the lower end of the pressurizing portion 25 of the plunger 20, the plunger 20 is raised so that the first valve body 131a of the suction portion 13 contacts the stop member 131b. The fluid is introduced into the first cylinder 10 from the suction unit 13. In addition, as shown in FIG. 2B, when the working fluid is introduced through the operation means connecting valve 40b on the upper end of the pressurizing portion 25 of the plunger 20, the upper end of the pressurizing portion 25 of the plunger 20 is introduced. Under pressure, the plunger 20 is lowered. On the contrary, the second valve body 151a of the discharge part 15 moves to the discharge part 15, but the elastic part 151b does not block the discharge part 15. As a result, the fluid introduced into the first cylinder 10 through the suction part 13 is discharged through the discharge part 15.

As shown in FIG. 3 again, between the body 21 and the pressing portion 25 of the plunger 20 is composed of a connecting portion 22 having a smaller diameter than the body 21, the body and 21 And the connecting portion 22 is composed of a single body, the diameter of the connecting portion 22 is configured to be smaller than the body 21. Therefore, the working fluid sucked by the actuating means connecting valve 40a exerts a pressure on the lower end of the pressurizing part to raise the plunger 20, which can be pressurized due to the connecting part 22 smaller than the body 21. As the area is increased, the pressure applied to the pressurization portion 25 by the working fluid may be increased.

The plunger 20 is moved up and down through the working fluid supplied to the upper and lower, the head 23 of the plunger 20 in the bottom dead center position of the pumping space of the first cylinder ( 11) By contacting the ground, there is no pressure loss by eliminating the space between the pumping space 11 and the plunger 20, the fluid introduced from the suction portion 13 can be efficiently discharged to the discharge portion. .

The suction part 13 and the discharge part 15 of the first cylinder 10 receive first and second valve bodies 131a and 151a and the valve bodies 131a and 151a, respectively, and are in fluid communication. First and second valves (131, 151) are provided, each having a connection body having a furnace (17),

When the fluid is sucked through the suction part 13, the first valve body 131a may move toward the first cylinder 10 due to the pressure of the suctioned fluid, thereby preventing the flow of the fluid. Therefore, in order to solve this problem, the first valve 131 on the suction part 13 is provided with a stop member 131b to prevent the first valve body 131a from being separated due to the fluid being sucked.

In addition, the discharge part 15 is provided with a second valve body 151a as a place where the sucked fluid is discharged, and the second valve body 151a is discharged by the downward movement of the plunger 20. The second valve 151 on the discharge part 15 side further includes elastic means 151b for blocking the discharge part 15 by holding the second valve body 151a so as to prevent movement of the fluid. Accordingly, when the fluid moves to the discharge part 15, the moving speed of the second valve body 151a may be reduced by the elastic force of the elastic means 151b and the fluid may be discharged due to the decrease in speed. It can be discharged through the (15).

The communication path 17 of the connecting body has a front valve body displacement path 17a, an intermediate elastic means accommodation path 17b, a rear discharge path 17c, and a displacement path 17a having a relatively large cross-sectional area. ) Has a cross-sectional tapered path 17d connecting the receiving passage 17b with a relatively small cross-sectional area.

When the pump is operated, the plunger 20 moves up and down, which causes the elastic means 151b of the discharge part 15 to move, and the elastic means 151b moves into the communication path 17 when contracted and expanded. In order to prevent the elastic means 151b from being damaged, the elastic means 151b is provided with a tapered path 17d so that the elastic means 151b can move without being caught in the communication path 17 through the tapered path 17d. 151b) improves durability by preventing wear and breakage.

In addition, the displacement path of the communication path 17 is characterized in that the side connection path for ensuring the flow rate is further provided.

As shown in FIG.

The head 23 of the plunger 20 is provided with an upper first sealing ring 23a and a lower second sealing ring 23b in contact with an inner wall of the pumping space 11 of the first cylinder 10. ,

The second sealing ring (23b) in contact with the pumping fluid first is characterized in that made of a material having the characteristics of durability or chemical resistance, or both,

The first sealing ring (23a) is made of a relatively soft material with a focus on ensuring the sealing,

The second sealing ring 23b, which first comes into contact with the pumping fluid during the pumping operation according to the linear reciprocating motion (for example, the lifting and lowering motion) of the plunger 20, may have, for example, durability or chemical resistance, such as Teflon material, or both. Both are made of a material having a characteristic to prevent damage to the first sealing ring (23a) by foreign matter contained in the pumping fluid to function for a long time pumping force.

In addition, the pressurization portion 25 of the plunger 20 is also provided with a third sealing ring 25a in contact with the inner wall of the ascending space 31 of the second cylinder 30, thereby pumping the vertical movement of the plunger. It can be in close contact with the inner wall of the space to ensure the sealing property so that the working fluid does not escape,

The inclination is given so that the diameter of the head 23 of the plunger 20 is larger than that of the body 21 of the plunger 20, so that the body 21 and the pumping space 11 of the plunger 20 are larger. In addition to forming a space in which the working fluid can flow therebetween, the body 21 of the plunger 20 does not come into contact with the inner wall of the pumping space 11 to prevent wear and breakage due to friction and impact. To improve the durability of the pump.

In addition, as shown in FIG. 5, a first fastening part 111 having a male screw part is provided at an upper portion of the pumping space 11 of the first cylinder 10.

The lower part of the second cylinder 30 is provided with a second fastening portion 32 having a female screw portion coupled to the male screw portion,

A packing ring 111a is coupled to a lower portion of the male screw portion of the first fastening portion 111, thereby preventing a gap generated when the first fastening portion 111 and the second fastening portion 32 are coupled to each other, thereby preventing air leakage. To prevent, the lower portion of the e-packing ring (111a) is provided with a support jaw (111b),

The first fastening portion has a sealed inner circumferential surface 32a in contact with the packing ring 111a and a support inner circumferential surface 32b intersecting with the support jaw 111b at the lower portion of the female screw portion of the second fastening portion 32. It is characterized in that the contact area of the male screw portion of the 111 and the female screw portion of the second fastening portion 32 is widened to increase the coupling force to prevent rocking of the fastened second cylinder 30.

In addition, in the above description of the present invention with reference to the accompanying drawings has been described mainly for improved durability plunger pump having a specific shape, structure and configuration, the present invention can be variously modified, changed and replaced by those skilled in the art, such Modifications, changes and substitutions should be construed as falling within the protection scope of the present invention.

A: pump 10: first cylinder
11: pumping space 111: first fastening portion
111a: Packing ring 111b: Supporting jaw
113: upper portion of the pumping space 13: suction portion
131: first valve 131a: first valve body
131b: stop member 15: discharge portion
151: second valve 151a: second valve body
151b: elastic means 17: communication path
17a: valve body displacement path 17b: elastic means receiving path
17c: discharge path 17d: cross-sectional area decrease
20: Plunger 21: Body
22: connection 23: head
23a: first sealing ring 23b: second sealing ring
25: pressurization portion 25a: third sealing ring
30: second cylinder 31: lifting space
32: second fastening portion 32a: sealed inner peripheral surface
32b: Inner support surface 40a, 40b: Actuator connecting valve
50: cap 51: pressure control member

Claims

A first cylinder 10 having a pumping space 11 and having a suction part 13 and a discharge part 15;
Coupled to the pumping space (11) of the first cylinder (10) for linear reciprocating motion, the body 21, the head 23 connected to one end of the body 21, and is provided at the other end of the body 21 A plunger 20 having a pressurizing portion 25;
Coupled to the first cylinder 10,
A second cylinder 30 covering the pumping space 11 of the first cylinder 10 and providing a lifting space 31 in which the pressing part 25 of the plunger 20 moves; And
Operating means connecting valves 40a and 40b for moving the plunger 20 by supplying a working fluid to the upper and lower portions of the pressurizing portion 25 of the plunger 20;
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The head 23 of the plunger 20 is in contact with the bottom surface of the pumping space 11 of the first cylinder 10 at the bottom dead center position for fluid discharge, the pressing portion 25 of the plunger 20 Is in contact with the upper end 113 of the pumping space of the first cylinder 10,

The first fastening part 111 having a male screw part is provided at the upper end 113 of the pumping space of the first cylinder 10,
The lower part of the second cylinder 30 is provided with a second fastening portion 32 having a female screw portion coupled to the male screw portion,
A packing ring 111a is coupled to a lower portion of the male screw portion of the first fastening portion 111, and a support jaw 111b is provided below the packing ring 111a.
A lower portion of the female screw portion of the second fastening portion 32 has a sealed inner circumferential surface 32a in contact with the packing ring 111a and a support inner circumferential surface 32b intersected with the support jaw 111b.
Durable plunger pump, characterized in that to prevent rocking of the fastened second cylinder (30).

The method of claim 1,
The suction part 13 and the discharge part 15 of the first cylinder 10 receive first and second valve bodies 131a and 151a, and the valve bodies 131a and 151a, respectively, and are in fluid communication. First and second valves (131, 151) each comprising a connecting body having a furnace (17) is provided,
The discharge part side second valve 151 is further provided with elastic means 151b for holding the valve body 151a to block the discharge part 15.

The communication path 17 of the connecting body
Forward valve body displacement path 17a,
An intermediate elastic means accommodation path 17b,
The discharge path 17c at the rear,
It has a cross-sectional tapered path 17d which connects the displacement path 17a having a relatively large cross-sectional area and the receiving passage 17b having a relatively small cross-sectional area, so that the elastic means 151b that contracts and expands moves without jamming. Durable plunger pump characterized by the above-mentioned.

The method of claim 1,
The head 23 of the plunger 20 is provided with an upper first sealing ring 23a and a lower second sealing ring 23b in contact with an inner wall of the pumping space 11 of the first cylinder 10. ,
The second sealing ring (23b) which first comes into contact with the pumping fluid is a durable plunger pump, characterized in that made of a material having the characteristics of durability or chemical resistance, or both.

The method according to any one of claims 1 to 3,
Between the body 21 and the pressing portion 25 of the plunger 20 is provided with a connecting portion 22 having a smaller diameter than the body 21,
The body 21 and the connecting portion 22 is composed of a single body, the diameter of the connecting portion 22 is configured smaller than the body 21,

The pressing portion 25 of the plunger 20 is provided with a third sealing ring 25a in contact with the inner wall of the rising space 31 of the second cylinder 30,
The inclination is given so that the diameter of the head 23 of the plunger 20 is larger than that of the body 21 of the plunger 20, so that the body 21 and the pumping space 11 of the plunger 20 are larger. In addition to forming a space in which the working fluid can be introduced therebetween, the durability of the plunger is characterized in that the body 21 of the plunger 20 does not come into contact with the inner wall of the pumping space 11. Pump.