TWI662191B - Uniaxial eccentric screw pump - Google Patents

Abstract

It has a stator (9) with an inner peripheral surface formed in the shape of a female screw, a rotor (10) that can be inserted into the stator (9) and consists of a male screw-type shaft, and can be placed on the outer periphery of the stator (9) The outer body (8) is moved between the first position on the side and the second position where the stator (9) is compressed, and the movement for moving the outer body (8) between the first position and the second position Means (7). Thereby, the contact pressure of the stator (9) to the rotor (10) can be stabilized, and the fluid can be discharged at a desired discharge pressure.

Description

Single shaft eccentric screw pump

The present invention relates to a uniaxial eccentric screw pump.

Generally speaking, in a uniaxial eccentric screw pump, because the stator will expand and contract according to changes in liquid temperature and air temperature, it may be difficult to move the fluid in an appropriate state corresponding to these changes. For example, in CIP (Cleaning In Place) and SIP (Sterilizing In Place), this problem occurs because high-temperature steam and hot water flow in the stator. In addition, when the stator wears and makes the tightness of the rotor small, it will become impossible to carry the fluid properly, and the stator will easily wear when the stator expands greatly, and the stator or rotor must be replaced as soon as possible. New product.

Conventionally, as a uniaxial eccentric screw pump capable of coping with such a problem, a stator made of an elastic body is housed in a casing, and the air pressure in a space formed between the casing and the stator is inserted with the rotor inserted in the stator. By adjusting the stator to elastically deform in the radial direction, the contact pressure between the stator and the rotor is maintained constant (for example, refer to Patent Document 1).

However, in order to maintain the contact pressure between the stator and the rotor, it is difficult to control the pressure in the space. If the pressure is large, for example, as shown in FIG. 9, the space for moving fluids formed between the rotor 101 and the stator 102, that is, the cavity 103 becomes small, and a desired discharge amount cannot be obtained. In addition, the friction between the rotor 101 and the stator 102 becomes larger, and in order to increase the torque of the rotation of the rotor 101, the stator 102 will wear out early. On the other hand, if the pressure is small, even if the rotor 101 is rotated, the fluid cannot flow sufficiently, and the fluid cannot be discharged at a desired discharge pressure.

In addition, because air pressure is directly applied to the stator 102, when damage to the stator 102 such as cracks occurs, air leakage may occur 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 be mixed into the fluid through the damaged portion, or the fluid may flow to the outside. When air is mixed in a flowing substance (especially food), it will cause quality problems. On the other hand, if it flows out to the surrounding area, the outflow part will be contaminated.

[Patent Document 1] Japanese Patent Laid-Open No. 60-173381

The object of the present invention is to provide a uniaxial eccentric screw pump which can stabilize the contact pressure of the stator to the rotor, and can discharge the fluid with a desired discharge pressure.

The present invention provides a uniaxial eccentric screw pump, which is a uniaxial eccentric screw pump including a stator and a rotor. The inner peripheral surface of the stator is formed into a female screw shape, and the rotor can be inserted into the stator It is composed of a male screw-type shaft body, and is characterized in that it is provided with an exterior body and a moving means. The exterior body can be at a first position on the outer peripheral side of the stator and a first position compressing the stator. Moving between two positions. This moving means is used to move the exterior body between the first position and the second position.

According to this structure, the contact pressure of the stator to the rotor can be changed only by changing the position of the exterior body by moving means. Therefore, the fastening force generated by the stator can be stabilized, and the stator can be prevented from abrasion, an increase in the rotation torque of the rotor, and a variation in the discharge pressure of the flowing material.

Preferably, 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 a loop to prevent them Further moves.

With this structure, the exterior portion does not exceed the second position to press the stator in. Therefore, the stator is not excessively pushed in, and it is possible to reliably prevent the occurrence of stator abrasion, an increase in the rotational torque of the rotor, and a change in the discharge pressure of the flowing material.

Preferably, a holding structure for holding the exterior part is provided. The holding member is made of an elastic material. When the outer covering portion is moved by the moving means, it is interposed between the two members to elastically press the outer covering portion.

According to this structure, the moving means indirectly moves the exterior body through the elastic holding member. Therefore, it is not easy to apply improper contact pressure from the stator to the rotor, and a better tightening state can be obtained.

Preferably, the moving means is provided with a sleeve which is arranged in a casing covering the stator and is elastically deformable inward to move the exterior body.

Preferably, the moving of the exterior body by the moving means is performed by fluid pressure.

According to this structure, according to the Pascal principle, a force is applied uniformly to the exterior body. Therefore, it is possible to prevent an abnormality such as an uneven amount of deformation of the stator caused by the local concentration of the force that inclines the exterior body.

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

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

The pressing member may be configured to be driven by an electromagnetic coil.

According to the present invention, the position is changed by moving the exterior body. This setting sets the fastening force of the stator to the rotor, so that the fastening force can be stably set to a desired value. Therefore, it is possible to reliably prevent abrasion of the stator, an increase in the rotational torque of the rotor, and a change in the discharge pressure of the fluid.

1‧‧‧shell

2‧‧‧Pump body

3‧‧‧ coupling rod

4‧‧‧ coupling

5‧‧‧ connecting pipe

6‧‧‧ Stator housing

7‧‧‧ sleeve (moving means)

8‧‧‧ Outer body

9‧‧‧ stator

9a‧‧‧center hole

9b‧‧‧ transport space

10‧‧‧ rotor

11‧‧‧ end stud

12‧‧‧ injection port

13‧‧‧Note out port

14‧‧‧The first on-off valve

15‧‧‧Control Valve

16a‧‧‧The first pressure gauge

17‧‧‧The second on-off valve

18‧‧‧ 2nd pressure gauge

19‧‧‧The first holder

20‧‧‧ 2nd gripper

21‧‧‧sealed space

22‧‧‧The first exterior department

23‧‧‧The second exterior department

24‧‧‧ Locating Pin

25‧‧‧ Wound body (holding member)

26‧‧‧ injection port

27‧‧‧Note out port

28‧‧‧The first exterior department

29‧‧‧The second exterior department

Fig. 1 is a schematic sectional view of a uniaxial eccentric screw pump according to a first embodiment.

FIG. 2 is a partially enlarged view of FIG. 1.

Fig. 3 is a sectional view taken along the line A-A in Fig. 2.

Fig. 4 is a partial sectional view of a uniaxial eccentric screw pump according to a second embodiment.

FIG. 5 is a sectional view showing only the exterior body and the wound body shown in FIG. 4.

Fig. 6 is a partial sectional view of a uniaxial eccentric screw pump according to another embodiment.

Fig. 7 is a partial sectional view of a uniaxial eccentric screw pump according to another embodiment.

Fig. 8 is a partial sectional view of a uniaxial eccentric screw pump according to another embodiment.

9 is a sectional view of a stator and a rotor of a conventional uniaxial eccentric screw pump.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Explanation. The following descriptions are merely illustrative in nature and are not intended to limit the present invention, its application, or its use. In addition, the drawings are schematic, and the ratios of dimensions are different from reality.

(First Embodiment)

Fig. 1 shows a uniaxial eccentric screw pump according to a first embodiment. This uniaxial eccentric screw pump is provided with 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 housing 1 is formed by forming a metal material into a cylindrical shape, and houses a coupling rod 3 therein. One end of the coupling rod 3 is connected to the coupling 4 so that the power from the driver is transmitted. In addition, a connection pipe 5 is connected to the outer peripheral surface of one end side of the casing 1, and a fluid can be supplied from a groove or the like (not shown).

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

One end portion of the stator case 6 and the case 1 are connected to each other by a flange and a bolt by a bolt and a nut. In addition, the other end portion of the stator case 6 and the end stud 11 are similarly connected to each other by bolts and nuts. These connecting portions are sealed with a gasket or the like (not shown). An injection port 12 is connected to the lower center portion of the stator case 6, and an injection port 13 is connected to the upper center portion. On the way to 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 in accordance with the stator case 6 side. As a result, the supplied control fluid (gas can also be used, but preferably a liquid After the pressure is adjusted by the regulator 16b, the control valve 15 and the first on-off valve 14 that are switched to the open position can be injected into the sealed space 21 described below through the injection port 12 after the pressure is adjusted by the regulator 16b. A second pressure gauge 18 and a second on-off valve 17 are provided along the piping connected to the injection port 13 in the order from the stator case 6 side. The second pressure gauge 18 detects the pressure of the control fluid in the sealed space 21. The control device detects pressure input (not shown). The control device adjusts the flow rate and pressure of the control fluid injected through the injection port 12 according to the input detection pressure, and opens and closes the second on-off valve 17 to thereby inject the control fluid in the sealed space 21.

The sleeve 7 is formed by forming an elastic material into a cylindrical shape. One end of the sleeve 7 is clamped between the inner peripheral surface of one end side of the stator case 6 and the outer peripheral surface of the first holder 19, and the other end of the sleeve 7 is clamped between the other parts of the stator case 6. Between the one end side inner peripheral surface and the outer peripheral surface of the second holder 20. In this manner, the first holder 19 and the second holder 20 can easily form an annular sealed space 21 between the sleeve 7 and the stator case 6. The control fluid is injected into the sealed space 21 through the injection port 12 and is injected from the sealed space 21 through the injection port 13. In FIG. 2, the maximum deformation state of the sleeve 7 that has undergone the maximum deformation by the injection of the control fluid is shown by a two-dot chain line, and the initial state before the deformation is shown by a solid line. The sleeve 7 is a moving means constituting the present invention, and the control body 8 is pushed inward by injecting a control fluid into the sealed space 21 from the injection port 12 to expand it inward.

Outer body 8 is made of metal material such as hard stainless steel or As shown in FIG. 3, a rigid body made of a synthetic resin material is composed of a first exterior portion 22 and a second exterior portion 23. The first outer covering portion 22 and the second outer covering portion 23 are formed into a cylindrical shape having a substantially circular outer periphery in cross section and an approximately 10-corner inner periphery. The facing surfaces of the first exterior portion 22 and the second exterior portion 23 are positioned by positioning pins 24. The positioning pin 24 has a male screw formed on one end side. In FIG. 3, two locations are positioned by positioning pins 24 (a first positioning pin 24a and a second positioning pin 24b). One end of the first positioning pin 24 a is screwed to the first exterior portion 22, and the other end thereof is slidably disposed in the second positioning hole 23 a of the second exterior portion 23. One end portion of the second positioning pin 24 b is screwed to the second exterior portion 23, and the other end portion thereof is slidably disposed in the first positioning hole 22 a of the first exterior portion 22. Thereby, the 1st exterior part 22 and the 2nd exterior part 23 can be contacted or separated in the state guided by the positioning pin 24. In this case, the first exterior portion 22 and the second exterior portion 23 may be formed in a first position where the stator 9 is not pressurized and a second position where the facing surfaces abut each other to form a 10-angle shape. Move between. 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. In addition, the first and second exterior portions 22 and 23 are rigid bodies, and the entire stator 9 can be uniformly compressed inward. Therefore, the contact pressure of the stator 9 to the rotor 10 does not cause unevenness in the axial center direction, and causes abnormalities such as pulsation. In addition, since they do not approach each other and approach each other, the contact pressure of the stator 9 to the rotor 10 is not excessively high.

The stator 9 is an elastic material (e.g., silicone rubber, fluorine rubber (the latter is suitable It is used for cosmetics containing silicone oil, etc.)) and formed into a cylindrical shape (for example, a circular cross-sectional shape). The inner hole 9a of the center hole 9a of the stator 9 is formed in the shape of n, one or more female screw threads.

The rotor 10 is formed by forming a shaft body made of a metallic material such as stainless steel into a male thread shape of n-1, single or multiple stages. The rotor 10 is disposed in a center hole 9a of the stator 9 and has a continuous conveyance space 9b formed along the length thereof. One end of the rotor 10 is connected to the coupling rod 3 on the casing side, and is driven to rotate inside the stator 9 by a driving force from a driving machine (not shown), and revolves along the inner peripheral surface of the stator 9. That is, the rotor 10 rotates eccentrically in the center hole 9 a of the stator 9, whereby the material in the transfer space 9 b can be transferred in the longitudinal direction.

Next, an assembling method of the uniaxial eccentric screw pump constituted by the aforementioned structure will be described.

First, the second holder 20 is integrated at one end portion of the stator 9 by press-fitting or the like. Next, the outer surfaces of the stator 9 having a substantially 10-angled shape are combined so that the inner surfaces of the first outer covering portion 22 and the second outer covering portion 23 are in contact with each other. At this time, the first exterior portion 22 and the second exterior portion 23 are aligned by the positioning pins 24. Next, the sleeve 7 is mounted on the outer periphery of the first and second outer covering portions 22 and 23 assembled to the stator 9 while sliding in the axial center direction. At the end opposite to the end where the second holder 20 is integrated, the first holder 19 is integrated by press-fitting or the like.

Each component (assembly) assembled in such a manner has the sleeve 7 tightly attached to the outer peripheral surface of the first outer covering portion 22 and the second outer covering portion 23, and The first holder 19 and the second holder 20 are integrated. Therefore, the inside of the sleeve 7 is hermetically sealed, and even if a crack or the like occurs in the stator 9 to cause leakage of the internal fluid, the sleeve 7 will not flow out further from the sleeve 7. In addition, the aforementioned unit is connected to one end portion of the housing 1 through a first holder 19. Next, the rotor 10 is inserted into the center hole 9 a of the stator 9 from the other end side of the housing 1, that is, the driver side. Further, the sub-shell 6 is set on the outer periphery of the sleeve 7 to complete the assembling operation. If the sub housing 6 is installed, the airtightness between the sleeve 7 and the stator housing 6 can be maintained by the first holder 19 and the second holder 20 to form a sealed space 21. Therefore, the control fluid injected into the sealed space 21 does not flow into the inside of the sleeve 7. In addition, not only the inner side of the sleeve, but also the airtightness can be maintained by using the sealed space 21, and even if a crack or the like occurs in the stator 9, there is no need to worry about the leakage of the fluid to the outside.

Next, the operation of the uniaxial eccentric screw pump configured as described above will be described.

The relationship between the injection amount of the control fluid toward the sealed space 21, the type of fluid, the rotation speed of the rotor 10, and the discharge pressure are set in advance. For example, the injection amount of the control fluid toward the sealed space 21 is set to the minimum value so that the sleeve 7 is in the initial state. Next, the relationship between the rotation speed of the rotor 10 and the discharge pressure is stored in the form of a data table according to the different types of fluid. In addition, the injection amount of the control fluid toward the sealed space 21 is gradually changed and the same process is performed to complete the data sheet.

When a fluid is discharged from a groove or the like, first, by opening the first on-off valve 14 or the like, the shape of the stator case 6 and the sleeve 7 is adjusted. The resulting sealed space 21 is filled with a control fluid. The injection amount of the control fluid into the sealed space 21 is determined by referring to the aforementioned data sheet, and the fluid can be discharged at a desired discharge pressure in accordance with the rotation speed of the rotor 10 described later. In this case, if the control fluid is a non-compressible fluid, the relationship between the injection amount and the discharge pressure is stable and does not change, which is preferable from this viewpoint.

If the discharge pressure is increased, the injection amount of the control fluid into the sealed space 21 can be increased, and the first exterior portion 22 and the second exterior portion 23 can be brought closer to each other through the sleeve 7. Thereby, the stator 9 is pressurized, and the contact pressure with the rotor 10 is increased. On the other hand, if the discharge pressure is suppressed, the injection amount of the control fluid can be suppressed, and the first exterior portion 22 and the second exterior portion 23 can be made not so close. In this way, the contact pressure of the stator 9 to the rotor 10 can be suppressed.

Next, a driving machine (not shown) is driven, and the rotor 10 is rotated at a predetermined rotation speed through the coupling 4 and the coupling rod 3. The rotation speed at this time is determined in consideration of the discharge amount per unit time. As described above, the transport space 9 b formed by the inner peripheral surface of the stator 9 and the outer peripheral surface of the rotor 10 moves in the longitudinal direction. The fluid discharged from the groove is sucked into the transfer space 9 b and is transferred toward the end stud 11. The fluid that has reached the end stud 11 is further transported to another location.

In this way, according to the uniaxial eccentric screw pump of the aforementioned structure, the following advantages can be obtained.

(1) Since the contact pressure of the stator 9 to the rotor 10 is adjusted, the fluid can be discharged from the end stud 11 at a desired discharge pressure.

(2) The force acting on the exterior body 8 from the sleeve 7 is determined by the injection amount of the control fluid into the sealed space 21 and is stable. In addition, in the stator 9, the exterior body 8 is brought into surface contact, and the pressing force can be uniformly applied. Therefore, the frictional resistance that the rotor 10 receives when it rotates is also based on the set contact pressure and is not easily changed. Therefore, when the rotor 10 rotates, the rotation torque does not increase.

(3) Even if an excessive force is temporarily applied to the stator 9 through the rotation of the rotor 10, only a certain pressure determined by the injection amount of the control fluid toward the sealed space 21 will be applied to the stator 9. Therefore, the stator 9 is elastically deformed toward the outer diameter side without causing damage. The stator 9 is pressed through the sleeve 7. Therefore, even if a crack or the like is generated in the stator 9, the surrounding area is covered by the sleeve 7, so that external air or the like does not enter the sleeve 7 from the outside, and the fluid does not leak to the surroundings and cause pollution.

(4) Because the suction side is low pressure and the discharge side is high pressure, when the control fluid is injected into the sealed space 21, the stator 9 is more easily compressed on the suction side than the discharge side (or on the discharge side). Expansion) and the presence of the exterior body 8 can prevent the degree of compression (or expansion on the discharge side) on the suction side from becoming excessive. That is, the entirety can be uniformly compressed, and the degree of compression when moving a fluid is not greatly changed.

A through hole may be formed in the first holder 19 or the second holder 20 to communicate the space between the sleeve 7 and the stator 9 with the outside. According to this structure, when there is a controlled fluid inflow in the sealed space 21, air passing between the first exterior portion 22, the second exterior portion 23, the sleeve 7, and the stator 9 can be exhausted through the through hole. As a result, with the sleeve 7 and through the exterior body 8, the stator 9 is subjected to an equal pressing force. When the stator 9 is damaged by cracks or the like, fluid flowing out from the inside of the stator 9 to the outside can flow out through the through-holes, so that an abnormality of the stator 9 can be detected early. In addition, when the sleeve 7 is damaged or the sleeve 7 is improperly assembled, the control fluid will flow out through the through hole, so these abnormalities can be detected early.

In addition, when suppressing the injection amount of the control fluid into the sealed space 21, the pressing force of the sleeve 7 on the first outer portion 22 and the second outer portion 23 is reduced, and the stator 9 is not compressed. can. For example, by suppressing the control fluid injection amount, the pressing force may be made zero. In this way, even if the stator 9 expands during stationary washing, stationary sterilization, etc., the first and second exterior portions 22 and 23 can still move freely outside, so it can be avoided that the stator 8 is crimped to The rotor 10 prevents abnormalities such as rotation.

(Second Embodiment)

Fig. 4 shows a uniaxial eccentric screw pump according to a second embodiment. This uniaxial eccentric screw pump is different from the aforementioned 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 descriptions thereof will be omitted.

On the outer periphery of the stator 9 are provided an exterior body 8 (the first exterior portion 28 and the second exterior portion 29), and a wound body 25 that is wound to position them around the stator 9. This wound body 25 is an example of the holding member of the present invention. Moreover, the stator case 6 and the The control fluid is injected into the sealed space 21 formed by the sleeve 7 and the sleeve 7 is expanded toward the inner diameter side, whereby the stator 9 is directed inward through the wound body 25, the first outer portion 28, and the second outer portion 29. Radial pressure was applied.

An injection port 26 is connected to the lower center of the stator case 6. Through the injection port 26, the control fluid can be injected into the sealed space 21 defined by the stator case 6 and the sleeve 7. In addition, an injection port 27 is connected to the center of the upper portion of the stator case 6 so that the control fluid can be injected. A pressure gauge is provided in the injection port 27 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 portion 28 and the second exterior portion 29 are formed in a plate shape different from the first embodiment described above. As shown in FIG. 5, these exterior portions 28 and 29 are arranged in a state of being arranged on the outer periphery of the stator 9, and have approximately a 10-angle shape along the shape of the outer surface of the stator 9. However, a gap is formed between both side edges of the first exterior portion 28 and the second exterior portion 29. Further, by pressing the first and second exterior portions 28 and 29 to bring the exterior bodies 28 and 29 closer, the stator 9 can be elastically deformed toward the inside. However, if the edges on both sides are in contact with each other, the stator 9 cannot be excessively compressed because it cannot move further.

The wound body 25 is made of heat-resistant plastic or the like and is wound around the outer body 8 to temporarily fix the stator 9 to the first outer portion 28 and the second outer portion 29 to prevent positional displacement. . That is, it is used to prevent: the first exterior portion 28 and the second exterior portion 29 from being displaced in the circumferential direction. Offset so that the edges of the two overlap each other. The first exterior portion 28 and the second exterior portion 29 are arranged along the shape of the outer surface of the stator 9, and the outer surfaces are approximately 10-angled. Even with such a polygonal shape, the wound body 25 can be wound, and the stator 9 can be temporarily fixed to the first exterior portion 28 and the second exterior portion 29 temporarily.

According to the uniaxial eccentric screw pump of the aforementioned structure, the assembly operation of the first outer portion 28 and the second outer portion 29 to the stator 9 is simple and low by winding the winding body 25 around these portions. Cost construction can be done. It is also unnecessary to align the exterior parts with each other with high accuracy. In addition, when the rotor 10 is rotated to transfer a fluid, the control fluid is injected into the sealed space 21 in advance so that the rotor 10 can be transferred at a desired discharge pressure. Thereby, the sleeve 7 is expanded inward, and the stator 9 is pressed by the outer body 8 through the wound body 25. In addition, the rotor 10 can be pressed by the stator 9 at a desired contact pressure, and the fluid can be discharged at a predetermined discharge pressure, which is the same as the first embodiment described above.

According to the uniaxial eccentric screw pump of the aforementioned structure, the structure of the exterior body 8 can be simplified, and it can be temporarily fixed only by winding the winding body 25 in a state along the stator 9. Therefore, workability can be improved and production can be performed at low cost.

The present invention is not limited to the structure described in the foregoing embodiment, and various changes can be made.

For example, in the aforementioned embodiment, the injection amount of the control fluid toward the sealed space 21 is determined in such a manner that it can be ejected at a desired ejection pressure in accordance with the rotation speed of the rotor 10, but it can also cooperate with the The abrasion state of the sub-9, the temperature, the change in the discharge amount of the fluid temperature of the fluid, and the change in the discharge pressure are determined. In the former case, the injection amount of the control fluid into the sealed space 21 can be determined in advance through experiments and the like so that the discharge amount (or discharge pressure) of the flowing material becomes a desired value in accordance with the elapsed time from the start of use. In the latter case, the injection amount of the control fluid into the sealed space 21 can be determined through experiments and the like in advance so that the discharge amount (or discharge pressure) of the flowing matter becomes a desired value in accordance with the air temperature and the liquid temperature of the flowing matter.

In addition, in the foregoing embodiment, the structure in which the exterior body 8 is divided into two parts, the first exterior part 22 and the second exterior part 23, has been described, but it may be configured to be divided into three or more. The example shown in FIG. 6 has a structure in which the exterior body 8 is divided into four exterior parts 8a to 8d having a quarter-round cross section. Each of the exterior parts 8a to 8d can be moved in the radial direction (inner diameter side and outer diameter side), and by moving to the innermost diameter side, the side end surfaces of adjacent exterior parts are in contact with each other, and they are connected in a ring shape status. Although not mentioned here, it is preferable to provide a positioning pin for guiding when the exterior portion reciprocates in the radial direction similarly to the previous embodiment.

Moreover, in the aforementioned embodiment, although the exterior body 8 is moved by the fluid pressure of the control fluid flowing into the sealed space 21, as shown in FIGS. 7 and 8, the exterior body is moved by pressing the member 30. The body 8 can also be moved.

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

In this case, the spring pressure of the spring 31 can be set to a value that can move the first exterior portion 22 upward when the internal pressure of the flowing material becomes larger than a preset value (set value). As the set value, for example, a value slightly larger than a desired discharge pressure may be used to absorb fluctuations in the discharge pressure.

Further, in addition to the spring 31, a driving mechanism for moving the first exterior portion 22 upward by using an air pressure or the like against the spring pressure of the spring 31 may be provided. According to this structure, unlike the case where only the spring 31 is provided, the force acting on the exterior body 8 can be finely adjusted similarly to the previous embodiment.

FIG. 8 adopts the same structure as that of FIG. 7, using a movable core as the pressing member 30, and placing an electromagnetic coil 32 on its outer periphery. The pressing member 30 is reciprocated by exciting and demagnetizing the electromagnetic coil 32, and the current value that is conducted during the excitation increases, thereby increasing the pressing force generated by the pressing member 30.

In addition, in FIGS. 7 and 8, the first exterior portion 22 is pressed only by the pressing member 30, but the second exterior portion 23 can be pressed by other pressing members, and can also be pressed in accordance with the exterior body 8. Divide the number to increase the pressing member.

Claims (7)

A uniaxial eccentric screw pump is a uniaxial eccentric screw pump provided with a stator and a rotor. The inner peripheral surface of the stator is formed into a female screw shape. The rotor can be inserted into the stator and is made of a male screw type shaft body. It is characterized in that it is provided with an exterior body and a moving means that can move between a first position on the outer peripheral side of the stator and a second position that compresses the stator. The moving means is The outer body is moved between the first position and the second position. The moving means is provided with a sleeve which is arranged in a casing covering the stator and can be elastically deformed inward to make the outer Body moves. The single-shaft eccentric screw pump according to item 1 of the scope of patent application, wherein the exterior body is composed of a plurality of exterior parts, and the adjacent exterior parts are moved to each other by moving to the second position. The side parts of each are abutted and connected in a loop to prevent further movement. The uniaxial eccentric screw pump according to item 2 of the scope of the patent application, further comprising a holding member for holding the exterior part, the holding member is made of an elastic material, and the exterior is made by the moving means. When the part is moved, it intervenes between the two members and applies elastic pressure to the exterior part. The uniaxial eccentric screw pump according to any one of claims 1 to 3, wherein the movement of the exterior body using the aforementioned moving means is performed by fluid pressure. The uniaxial eccentric screw pump according to any one of claims 1 to 3, wherein the movement of the exterior body using the movement means is performed by pressing a member. The single-axis eccentric screw pump according to item 5 of the scope of patent application, wherein the pressing member can be driven by a spring. The single-axis eccentric screw pump according to item 5 of the scope of patent application, wherein the pressing member can be driven by an electromagnetic coil.