WO2016111040A1

WO2016111040A1 - Single-axis eccentric screw pump

Info

Publication number: WO2016111040A1
Application number: PCT/JP2015/074717
Authority: WO
Inventors: 哲男山根; 健斗塚本
Original assignee: 兵神装備株式会社
Priority date: 2015-01-09
Filing date: 2015-08-31
Publication date: 2016-07-14
Also published as: TWI662191B; DE112015005921T5; JP6421372B2; CN107110153B; MY186111A; CN107110153A; KR20170093916A; JP2016128670A; KR101930664B1; TW201629350A

Abstract

A single-axis eccentric screw pump is provided with: a stator 9 having an inner surface formed in a female screw-thread shape; a rotor 10 capable of being inserted through the stator 9 and comprising a shaft body having a male screw-thread shape; an outer cover body 8 capable of moving between a first position which is on the outer peripheral side of the stator 9 and a second position at which the outer cover body 8 compresses the stator 9; and a movement means 7 for moving the outer cover body 8 between the first position and the second position. As a result of this configuration, the contact pressure of the stator 9 on the rotor 10 is stabilized, and fluid is discharged at a desired discharge pressure.

Description

Uniaxial eccentric screw pump

The present invention relates to a uniaxial eccentric screw pump.

Generally, in a uniaxial eccentric screw pump, the stator expands and contracts in response to changes in liquid temperature and air temperature, and therefore it may be difficult to convey the fluid in an appropriate state corresponding to those changes. For example, CIP (Cleaning In Place) and SIP (Sterilizing InlacePlace) cause high temperature steam or hot water to flow into the stator, which causes this problem. In addition, if the stator wears and the tightening allowance on the rotor becomes small, the fluid cannot be conveyed properly. It becomes necessary to replace it with a new one.

Conventionally, as a uniaxial eccentric screw pump capable of coping with such a problem, a stator made of an elastic body is accommodated in a casing, and a rotor is inserted into the stator. A device is known in which the contact pressure with the rotor is kept constant by adjusting the air pressure and elastically deforming the stator in the radial direction (see, for example, Patent Document 1).

However, it is actually difficult to control how much pressure is set in the space in order to keep the contact pressure of the stator to the rotor constant. When the pressure is high, for example, as shown in FIG. 9, the cavity 103, which is a fluid conveyance space formed between the rotor 101 and the stator 102, becomes small, and a desired discharge amount cannot be obtained. Further, the frictional force between the rotor 101 and the stator 102 is increased, and the torque for rotating the rotor 101 is increased, or the stator 102 is worn early. On the other hand, if the pressure is small, the fluid cannot be sufficiently flowed even if the rotor 101 is rotated, and it is impossible to discharge the fluid at a desired discharge pressure.

In addition, since air pressure is directly applied to the stator 102, when damage such as a crack occurs in the stator 102, air may leak from the damaged portion. In this case, the stator 102 cannot be pressed against the rotor 101 with a desired contact pressure. In addition, air may enter the fluid through the damaged portion, or the fluid may flow out to the outside. If air is mixed into the fluid (especially food), there is a problem in quality, and if it flows out to the surroundings, the outflow part is contaminated.

JP 60-173381 A

An object of the present invention is to provide a uniaxial eccentric screw pump capable of stabilizing a contact pressure to a rotor by a stator and discharging a fluid with a desired discharge pressure.

As a means for solving the above problems, the present invention provides:
A stator having an inner peripheral surface formed into a female screw type;
A rotor that can be inserted through the stator and has a male screw shaft;
A uniaxial eccentric screw pump comprising:
An exterior body movable between a first position on the outer peripheral side of the stator and a second position for compressing the stator;
Moving means for moving the exterior body between the first position and the second position;
A uniaxial eccentric screw pump characterized by comprising:

This configuration makes it possible to change the contact pressure of the stator with respect to the rotor only by changing the position of the exterior body by the moving means. Accordingly, it is possible to stabilize the tightening force by the stator and prevent the wear of the stator, the increase of the rotational torque of the rotor, or the fluctuation of the discharge pressure of the fluid.

The exterior body is composed of a plurality of exterior parts, and by moving to the second position, the side parts of the adjacent exterior parts are in contact with each other to form an annular shape, preventing further movement. Is preferred.

∙ With this configuration, the exterior portion does not push the stator beyond the second position. Therefore, it is possible to reliably prevent the stator from being pushed in more than necessary to cause the stator to wear, the rotor rotational torque to increase, or the fluid discharge pressure to fluctuate.

A holding member for holding the exterior part;
It is preferable that the holding member is made of an elastic material, and when the exterior portion is moved by the moving unit, the exterior portion is urged by being interposed between both members.

With this configuration, the moving means moves the exterior body indirectly through the elastic holding member. Therefore, an excessive contact pressure from the stator does not easily act on the rotor, and an even better tightening state can be obtained.

The moving means may be provided in a casing that covers the stator, and may include a sleeve that is elastically deformed inward to move the exterior body.

The movement of the exterior body by the moving means may be performed based on fluid pressure.

This configuration allows a uniform force to be applied to the exterior body according to the Pascal principle. Therefore, it is possible to prevent the occurrence of problems such as uneven deformation of the stator due to the force being partially concentrated and the exterior body being inclined.

The movement of the exterior body by the moving means may be performed by a pressing member.

In this case, the pressing member may be driven by a spring.

The pressing member may be driven by a solenoid.

According to the present invention, since the tightening force of the rotor by the stator is set according to the position to move the exterior body, this tightening force can be stabilized to a desired value. Accordingly, it is possible to reliably prevent the wear of the stator, the increase of the rotational torque of the rotor, or the fluctuation of the discharge pressure of the fluid.

It is a schematic sectional drawing of the uniaxial eccentric screw pump concerning a 1st embodiment. It is the elements on larger scale of FIG. FIG. 3 is a sectional view taken along line AA in FIG. 2. It is a fragmentary sectional view of the uniaxial eccentric screw pump concerning a 2nd embodiment. FIG. 5 is a cross-sectional view of only the exterior body and the wound body shown in FIG. 4. It is a fragmentary sectional view of the uniaxial eccentric screw pump concerning other embodiments. It is a fragmentary sectional view of the uniaxial eccentric screw pump concerning other embodiments. It is a fragmentary sectional view of the uniaxial eccentric screw pump concerning other embodiments. It is sectional drawing of the stator and rotor of a uniaxial eccentric screw pump concerning a prior art.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use. Further, the drawings are schematic, and the ratio of each dimension is different from the actual one.

(First embodiment)
FIG. 1 shows a uniaxial eccentric screw pump according to a first embodiment. This uniaxial eccentric screw pump includes a driving machine (not shown) provided on one end side of the casing 1 and a pump body 2 provided on the other end side.

The casing 1 is a cylindrical metal material, and a coupling rod 3 is accommodated. One end of the coupling rod 3 is connected to the coupling 4 so that power from the driving machine is transmitted. A connecting pipe 5 is connected to the outer peripheral surface at one end of the casing 1 so that a fluid can be supplied from a tank or the like (not shown).

The pump body 2 includes a sleeve 7, an exterior body 8, a stator 9, and a rotor 10 housed in a stator casing 6, and an end stud 11 is attached to the end of the stator 9.

The casing 1 is connected to one end portion of the stator casing 6 by bolts and nuts. An end stud 11 is connected to the other end of the stator casing 6, and the flanges are similarly connected to each other by bolts and nuts. These connecting portions are sealed with packing or the like (not shown). An injection port 12 is connected to the lower central portion of the stator casing 6, and an extraction port 13 is connected to the upper central portion. In the middle of the piping connected to the injection port 12, a first on-off valve 14, a control valve 15, a first pressure gauge 16a, and a regulator (pressure regulator) 16b are provided in this order from the stator casing 6 side. As a result, the control fluid 15 (which may be a gas but is preferably an incompressible fluid typified by liquid) is adjusted by the regulator 16b and switched to an open position, and In addition, it is possible to inject into the sealed space 21 described later through the injection port 12 from the opened first on-off valve 14. A second pressure gauge 18 and a second on-off valve 17 are provided in order from the stator casing 6 side in the middle of the piping connected to the dispensing port 13. The second pressure gauge 18 detects the pressure of the control fluid in the sealed space 21. The detected pressure is input to a control device (not shown). The control device adjusts the flow rate and pressure of the control fluid injected through the injection port 12 based on the input detected pressure, and opens and closes the second on-off valve 17 to control the control fluid in the sealed space 21. It can be dispensed.

The sleeve 7 is a cylindrical elastic material. The sleeve 7 has an opening at one end sandwiched between the inner peripheral surface at one end of the stator casing 6 and the outer peripheral surface of the first clamp 19, and an opening at the other end is connected to the inner peripheral surface at the other end of the stator casing 6 and the second end. It is clamped between the outer peripheral surface of the clamp 20. Thus, the annular sealing space 21 can be easily formed between the sleeve 7 and the stator casing 6 by the first clamp 19 and the second clamp 20. The control fluid is injected into the sealed space 21 through the injection port 12 and is discharged through the extraction port 13. In FIG. 2, the maximum deformation state of the sleeve 7 most deformed by the injection of the control fluid is indicated by a two-dot chain line, and the initial state before the deformation is indicated by a solid line. The sleeve 7 constitutes a moving means according to the present invention, and inflates inward by injecting a control fluid from the injection port 12 into the sealed space 21 and presses the exterior body 8.

The exterior body 8 is a rigid body made of a hard metal material such as stainless steel or a synthetic resin material, and includes a first exterior part 22 and a second exterior part 23 as shown in FIG. The first exterior part 22 and the second exterior part 23 form a cylindrical shape in which the outer periphery of the cross section is substantially circular and the inner periphery is substantially decagonal. Opposing surfaces of the first exterior part 22 and the second exterior part 23 are positioned by positioning pins 24. The positioning pin 24 is formed with a male screw on one end side. In FIG. 3, two positions are positioned by positioning pins 24 (first positioning pins 24a and second positioning pins 24b). One end of the first positioning pin 24 a is screwed into the first exterior part 22, and the other end is slidably disposed in the second positioning hole 23 a of the second exterior part 23. One end of the second positioning pin 24 b is screwed into the second exterior portion 23, and the other end is slidably disposed in the first positioning hole 22 a of the first exterior portion 22. As a result, the first exterior portion 22 and the second exterior portion 23 are brought into contact with and separated from each other while being guided by the positioning pins 24. In this case, the first exterior portion 22 and the second exterior portion 23 move between a first position where the stator 9 is not pressurized and a second position where the opposing surfaces are brought into contact with each other to form a decagon. Is possible. When the first exterior portion 22 and the second exterior portion 23 approach from the first position toward the second position, the inner surface side is brought into surface contact with the outer surface of the stator 9. And the 1st exterior part 22 and the 2nd exterior part 23 are rigid bodies, and compress the whole stator 9 uniformly inward. Therefore, there is no problem that the contact pressure of the stator 9 with respect to the rotor 10 varies in the axial direction and pulsation or the like occurs. Moreover, since it does not approach beyond the 2nd position, the contact pressure of the stator 9 with respect to the rotor 10 is not raised any more.

The stator 9 is an elastic material such as rubber or resin selected according to the fluid to be conveyed as appropriate (for example, silicon rubber, fluororubber (the latter is used for cosmetics in which the fluid contains silicone oil). ) In a cylindrical shape (for example, a circular cross-sectional shape). The center hole 9a of the stator 9 has a single-stage or multi-stage female screw shape with an inner circumferential surface having n strips.

The rotor 10 has a shaft body made of a metal material such as stainless steel in a single-stage or multi-stage male screw shape with n-1 strips. The rotor 10 is disposed in the center hole 9a of the stator 9 and forms a transport space 9b connected in the longitudinal direction. One end of the rotor 10 is connected to the coupling rod 3 on the casing side, and rotates around the inner side of the stator 9 and revolves along the inner peripheral surface of the stator 9 by a driving force from a driving machine (not shown). That is, the rotor 10 rotates eccentrically in the center hole 9a of the stator 9 so that the material in the transfer space 9b can be transferred in the longitudinal direction.

Subsequently, a method for assembling the single-shaft eccentric screw pump having the above-described configuration will be described.

First, the second clamp 20 is integrated with one end of the stator 9 by press fitting or the like. And it combines so that each inner surface of the 1st exterior part 22 and the 2nd exterior part 23 may contact | abut to the outer surface used as the substantially decagon of the stator 9. FIG. At this time, the first exterior portion 22 and the second exterior portion 23 are aligned by the positioning pin 24. Subsequently, the sleeve 7 is mounted on the outer periphery of the first exterior portion 22 and the second exterior portion 23 assembled to the stator 9 while sliding in the axial direction. The first clamp 19 is integrated by press-fitting or the like at the end opposite to the integration of the second clamp 20.

In each member (assembled product) assembled in this manner, the sleeve 7 is in close contact with the outer peripheral surfaces of the first exterior part 22 and the second exterior part 23, and the first clamp 19 and the second clamp 20 are attached to both ends. And are integrated. Accordingly, the inside of the sleeve 7 is sealed, and even if a crack or the like occurs in the stator 9 and the fluid inside leaks, the sleeve 7 does not flow further outward. The assembly is connected to one end of the casing 1 via a first clamp 19. Then, the rotor 10 is inserted into the center hole 9 a of the stator 9 from the other end side of the casing 1, that is, from the drive machine side. Further, the stator casing 6 is mounted on the outer periphery of the sleeve 7 to complete the assembling work. When the stator casing 6 is mounted, the airtightness between the sleeve 7 and the stator casing 6 is maintained by the first clamp 19 and the second clamp 20, and the sealed space 21 can be formed. Therefore, the control fluid injected into the sealed space 21 does not flow into the sleeve 7. Further, since the airtightness can be maintained not only by the inside of the sleeve but also by the sealed space 21, there is no fear that the fluid leaks to the outside even if a crack or the like occurs in the stator 9.

Next, the operation of the uniaxial eccentric screw pump having the above configuration will be described.

The relationship among the injection amount of the control fluid into the sealed space 21, the type of fluid, the rotational speed of the rotor 10, and the discharge pressure is set in advance. For example, the sleeve 7 is positioned in the initial state with the injection amount of the control fluid into the sealed space 21 as the minimum value. And the relationship between the rotational speed of the rotor 10 and discharge pressure is memorize | stored as a data table for every kind of fluid. Further, the amount of control fluid injected into the sealed space 21 is changed in stages, and the same processing is performed to complete the data table.

When discharging a fluid from a tank or the like, first, a control fluid is injected into the sealed space 21 formed by the stator casing 6 and the sleeve 7 by opening the first on-off valve 14 or the like. The amount of the control fluid injected into the sealed space 21 is determined with reference to the data table so that the fluid can be discharged at a desired discharge pressure according to the rotational speed of the rotor 10 described later. In this case, if the control fluid is an incompressible fluid, it is preferable in that the relationship between the injection amount and the discharge pressure can be made stable without fluctuation.

If the discharge pressure is increased, the injection amount of the control fluid into the sealed space 21 is increased, and the first exterior part 22 and the second exterior part 23 are brought close to each other via the sleeve 7. Thereby, the stator 9 is pressurized and the contact pressure with the rotor 10 increases. On the other hand, if the discharge pressure is suppressed, the injection amount of the control fluid is suppressed so that the first exterior portion 22 and the second exterior portion 23 do not approach so much. Thereby, the contact pressure of the stator 9 with respect to the rotor 10 is suppressed.

Subsequently, a driving machine (not shown) is driven, and the rotor 10 is rotated at a preset rotational speed via the coupling 4 and the coupling rod 3. The rotational speed at this time is determined in consideration of the discharge amount per unit time. Thereby, the conveyance space 9b formed by the inner peripheral surface of the stator 9 and the outer peripheral surface of the rotor 10 moves in these longitudinal directions. The fluid discharged from the tank is sucked into the transfer space 9 b and transferred to the end stud 11. The fluid reaching the end stud 11 is further transported to another place.

Thus, according to the uniaxial eccentric screw pump having the above-described configuration, the following advantages can be obtained.
(1) Since the contact pressure of the stator 9 with respect to the rotor 10 is adjusted, the fluid can be discharged from the end stud 11 with a desired discharge pressure.
(2) The force applied from the sleeve 7 to the exterior body 8 is determined by the amount of control fluid injected into the sealed space 21 and is stable. Further, the outer casing 8 is in surface contact with the stator 9 and applies a pressing force uniformly. For this reason, the frictional resistance that the rotor 10 receives during rotation is only due to the set contact pressure, and is not easily changed. Therefore, the rotational torque does not increase when the rotor 10 is rotated.
(3) Even if an excessively large force is temporarily applied to the stator 9 due to the rotation of the rotor 10, only a certain pressure determined by the amount of control fluid injected into the sealed space 21 is applied to the stator 9. It is. For this reason, the stator 9 is flexibly deformed toward the outer diameter side and does not cause damage. Moreover, the stator 9 is pressed through the sleeve 7. Therefore, even if a crack or the like is formed in the stator 9, the periphery is covered with the sleeve 7, so that outside air or the like enters the sleeve 7 from the outside, or a fluid leaks to the periphery. There is no contamination.
(4) Since the suction side has a low pressure and the discharge side has a high pressure, when the control fluid is injected into the sealed space 21, the stator 9 is more easily compressed (or greatly expanded on the discharge side) than the discharge side. The presence of the body 8 can prevent the degree of compression on the suction side (or expansion on the discharge side) from becoming too large. That is, it can compress uniformly as a whole, and the compression degree at the time of conveying a fluid does not change a lot.

In addition, you may make it form in the 1st clamp 19 or the 2nd clamp 20 the through-hole which connects the space between the sleeve 7 and the stator 9, and the exterior. According to this, when the control fluid flows into the sealed space 21, the air interposed between the first exterior portion 22 and the second exterior portion 23 and the sleeve 7 and the stator 9 is discharged through the through hole. can do. As a result, the sleeve 7 can apply a pressing force evenly to the stator 9 via the outer package 8. Further, when damage such as a crack occurs in the stator 9, the fluid leaking from the inside of the stator 9 to the outside flows out through the through hole, so that an abnormality of the stator 9 can be detected at an early stage. Further, when the sleeve 7 is damaged or when the sleeve 7 is not properly assembled, the control fluid flows out through the through hole, so that these abnormalities can be detected early.

Further, when the amount of the control fluid injected into the sealed space 21 is suppressed, the pressing force of the first exterior portion 22 and the second exterior portion 23 by the sleeve 7 may be small so that the stator 9 is not compressed. For example, the pressing force may be zero by suppressing the control fluid injection amount. As a result, even if the stator 9 expands due to stationary cleaning, stationary sterilization, or the like, the first exterior portion 22 and the second exterior portion 23 are in a state of being freely movable outward, so that the stator 8 can move to the rotor 10. Inconveniences such as preventing the rotation by being pressed against the surface are not caused.

(Second Embodiment)
FIG. 4 shows a uniaxial eccentric screw pump according to the second embodiment. This uniaxial eccentric screw pump differs from the first embodiment in the following points. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The outer periphery of the stator 9 is provided with an exterior body 8 (first exterior portion 28 and second exterior portion 29) and a wound body 25 that is wound around the stator 9 to position them. This wound body 25 is an example of the holding member of the present invention. Then, by injecting a control fluid into a sealed space 21 formed by the stator casing 6 and the sleeve 7 disposed on the inner diameter side thereof, the sleeve 7 is expanded to the inner diameter side, whereby the wound body 25, the first exterior portion The stator 9 is pressurized toward the inner diameter side via the 28 and the second exterior part 29.

The injection port 26 is connected to the lower center of the stator casing 6. The control fluid can be injected into the sealed space 21 defined by the stator casing 6 and the sleeve 7 through the injection port 26. Further, a pouring port 27 is connected to the upper center of the stator casing 6 so that the control fluid can be poured. The discharge port 27 is provided with a pressure gauge to detect the pressure of the control fluid in the sealed space 21. The pressure detected by the pressure gauge is input to a control device (not shown) and is used to control the flow rate and pressure of the control fluid injected through the injection port 26.

The first exterior part 28 and the second exterior part 29 are formed in a plate shape, unlike those according to the first embodiment. As shown in FIG. 5, the

exterior portions

28 and 29 are substantially dodecagons that conform to the outer surface shape of the stator 9 when arranged on the outer periphery of the stator 9. However, a gap is formed between both side edges of the first exterior part 28 and the second exterior part 29. And by pressing the 1st exterior part 28 and the 2nd exterior part 29, the

exterior parts

28 and 29 can be approached and the stator 9 can be elastically deformed inside. However, if both side edges are in contact with each other, the stator 9 cannot be compressed more than necessary because it cannot be moved further.

The wound body 25 is made of heat-resistant plastic or the like, wound around the exterior body 8, and prevents the first exterior portion 28 and the second exterior portion 29 from being temporarily displaced with respect to the stator 9 to be displaced. Used for That is, the first exterior portion 28 and the second exterior portion 29 are prevented from being displaced in the circumferential direction and the edges of both are prevented from overlapping each other. The first exterior portion 28 and the second exterior portion 29 are arranged along the outer surface shape of the stator 9, and the outer surfaces are substantially decagonal. Even if the wound body 25 has such a polygonal shape, it can be wound, and the first exterior portion 28 and the second exterior portion 29 can be easily temporarily fixed to the stator 9.

In the uniaxial eccentric screw pump having the above-described configuration, the assembly work of the first exterior portion 28 and the second exterior portion 29 to the stator 9 is performed with a simple and inexpensive configuration in which the wound body 25 is wound around them. Can do. It is not necessary to align the exterior parts with high accuracy. In addition, when the fluid is conveyed by rotating the rotor 10, a control fluid is injected into the sealed space 21 so that the fluid can be conveyed at a desired discharge pressure in advance. As a result, the sleeve 7 expands inward, and the stator 9 is pressed by the exterior body 8 via the wound body 25. The rotor 9 can be pressed by the stator 9 with a desired contact pressure, and the fluid can be discharged at a predetermined discharge pressure, as in the first embodiment.

According to the uniaxial eccentric screw pump having the above-described configuration, the configuration of the exterior body 8 can be simplified and temporarily fixed by simply winding the wound body 25 along the stator 9. Therefore, workability can be improved and it can be manufactured at low cost.

In addition, this invention is not limited to the structure described in the said embodiment, A various change is possible.

For example, in the above embodiment, the amount of the control fluid injected into the sealed space 21 is determined so as to be discharged at a desired discharge pressure according to the rotational speed of the rotor 10. You may determine according to the change of the discharge amount and discharge pressure accompanying the liquid temperature change of an animal. In the former case, the amount of the control fluid injected into the sealed space 21 is determined based on the elapsed time from the start of use so that the discharge amount (or discharge pressure) of the fluid becomes a desired value based on the elapsed time from the start of use. do it. In the latter case, the amount of the control fluid injected into the sealed space 21 is determined by experiments or the like in advance so that the discharge amount (or discharge pressure) of the fluid becomes a desired value based on the temperature or the liquid temperature of the fluid. Just decide.

In the above-described embodiment, the example in which the exterior body 8 is configured by two divisions of the first exterior portion 22 and the second exterior portion 23 has been described. However, the exterior body 8 may be configured by three or more divisions. FIG. 6 shows an example in which the exterior body 8 is configured by four divisions consisting of four exterior portions 8a to 8d having a ¼ circle cross section. Each of the exterior portions 8a to 8d can move in the radial direction (inner diameter side and outer diameter side), and by moving to the inner diameter side, the side end surfaces of the adjacent exterior portions abut each other, and are connected in an annular shape. It becomes a state. Although not mentioned here, it is preferable to provide a positioning pin that guides when the exterior portion reciprocates in the radial direction, as in the above-described embodiment.

Moreover, in the said embodiment, although the exterior body 8 was moved with the fluid pressure of the control fluid which flowed in in the sealed space 21, as shown in FIG.7 and FIG.8, the exterior body 8 is made by the press member 30. FIG. You may make it move.

In FIG. 7, the 1st exterior part 22 is arrange | positioned at the upper half part, and the 2nd exterior part 23 is arrange | positioned at the lower half part. Then, the first exterior part 22 is movable in the vertical direction, and the second exterior part 23 is supported so as not to be displaced. The first exterior portion 22 has a flange-shaped pressing portion 30 a on one end side, and is pressed by a rod-shaped pressing member 30 urged downward by a spring 31.

In this case, the urging force of the spring 31 may be set to a value that allows the first exterior portion 22 to move upward when the internal pressure becomes larger than a preset value (set value) due to the fluid. As the set value, for example, a value slightly larger than the desired discharge pressure may be set so as to absorb the fluctuation of the discharge pressure.

Further, in addition to the spring 31, a drive mechanism that moves the first exterior portion 22 upward against the urging force of the spring 31 by air pressure or the like may be provided. According to this, unlike the case where only the spring 31 is provided, the force applied to the exterior body 8 can be finely adjusted as in the above-described embodiment.

8, the structure is the same as in FIG. 7, and the pressing member 30 is a movable iron core, and a solenoid 32 is disposed on the outer periphery thereof. The pressing member 30 is reciprocated by exciting and demagnetizing the solenoid 32, and the pressing force by the pressing member 30 is increased by increasing the current value that is conducted when the solenoid 32 is excited.

7 and 8, only the first exterior part 22 is pressed by the pressing member 30, but the second exterior part 23 may also be pressed by another pressing member. The number of pressing members can be increased according to the number of divisions.

DESCRIPTION OF SYMBOLS 1 ... Casing 2 ... Pump main body 3 ... Coupling rod 4 ... Coupling 5 ... Connection pipe 6 ... Stator casing 7 ... Sleeve (moving means)
DESCRIPTION OF SYMBOLS 8 ... Exterior body 9 ... Stator 9a ... Center hole 9b ... Transfer space 10 ... Rotor 11 ... End stud 12 ... Injection port 13 ... Outlet port 14 ... First on-off valve 15 ... Control valve 16 ... First pressure gauge 17 ... First 2 on-off valve 18 ... second pressure gauge 19 ... first clamp 20 ... second clamp 21 ... sealed space 22 ... first exterior part 23 ... second exterior part 24 ... positioning pin 25 ... wound body (holding member)
26 ... Injection port 27 ... Pouring port 28 ... First exterior part 29 ... Second exterior part

Claims

A stator having an inner peripheral surface formed into a female screw type;
A rotor that can be inserted through the stator and has a male screw shaft;
A uniaxial eccentric screw pump comprising:
An exterior body movable between a first position on the outer peripheral side of the stator and a second position for compressing the stator;
Moving means for moving the exterior body between the first position and the second position;
A uniaxial eccentric screw pump characterized by comprising:
The exterior body is composed of a plurality of exterior parts, and by moving to the second position, the side parts of the adjacent exterior parts are in contact with each other to form an annular shape and prevent further movement. The uniaxial eccentric screw pump according to claim 1.
A holding member for holding the exterior part;
The uniaxial eccentric screw according to claim 2, wherein the holding member is made of an elastic material, and when the exterior portion is moved by the moving means, the exterior portion is urged by being interposed between the two members. pump.
4. The uniaxial shaft according to claim 1, wherein the moving unit includes a sleeve that is disposed in a casing that covers the stator and elastically deforms inward to move the exterior body. 5. Eccentric screw pump.
The uniaxial eccentric screw pump according to any one of claims 1 to 4, wherein the outer body is moved by the moving means based on a fluid pressure.
The uniaxial eccentric screw pump according to any one of claims 1 to 4, wherein the outer body is moved by the moving means by a pressing member.
The uniaxial eccentric screw pump according to claim 6, wherein the pressing member can be driven by a spring.
The uniaxial eccentric screw pump according to claim 6, wherein the pressing member can be driven by a solenoid.