JP2010281280A - Method and device for diagnosing deterioration of rubber member to be used for single-shaft eccentric screw pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To replace a female screw type stator of a single-shaft eccentric screw pump with the optimum timing by accurately grasping deteriorating conditions of a rubber stator impossible to be directly measured, while considering influences of the temperature of a fluid to be transported. <P>SOLUTION: This method of diagnosing deterioration of a rubber member to be used for a single-shaft eccentric screw pump includes: a hardness measuring process for measuring harness of a stator 1; and a region determining process for determining a safe region when the hardness measured in the hardness measuring process is a first set value or less, for determining a cautious region when the hardness measured in the hardness measuring process exists in a range from the first set value to a second set value larger than the first set value, and for determining a replace region when the hardness measured in the hardness measuring process exists in a range larger than the second set value. In the hardness measuring process, when the temperature of a fluid flowing in an inner hole 7 of the stator 1 is higher than a preset and prescribed temperature, hardness of an end of the stator 1 on a downstream side in the flowing direction among both ends of the stator 1 is measured, and when the temperature of the fluid is lower than the preset and prescribed temperature, hardness in a central part of the stator 1 is measured. In the region determining process, region determination is performed based on the hardness measured in the hardness measuring process. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method and apparatus for diagnosing deterioration of a rubber member used in a uniaxial eccentric screw pump.

  Conventionally, for example, the following is well known for diagnosing the deterioration state of a rubber member.

  In Patent Document 1, the pressure surface of an Asker F hardness meter is brought into contact with the outer peripheral surface of a developer supply sponge rubber roll that supplies developer from a developer cartridge to a developer carrier, and the measured value is 30 or more and 70 or less. The point of using the thing is disclosed.

  In Patent Document 2, if the tooth part of a toothed belt is covered with a tooth cloth colored with a pigment of a color different from that of the tooth part, and the tooth part is worn out and the tooth part is exposed, the life of the tooth part is changed due to the change in color. A toothed belt that can be determined as follows is disclosed.

  In Patent Document 3, the hardness of the rolling surface after the start of use of the rotary kiln tire or the support roller is measured, and the measured hardness is compared with the limit hardness at which cracks and peeling occur on the rolling surface. On the other hand, there is disclosed a method for diagnosing deterioration of a rotary kiln tire or support roller for diagnosing that the rolling surface deterioration is progressing as the measured hardness is closer.

  However, the rubber roll described in Patent Document 1 is merely selected to have an appropriate hardness when used. The degree of deterioration of the rubber roll is not determined based on the detected hardness.

  The toothed belt described in Patent Document 2 is premised on the abrasion of the surface tooth cloth. For this reason, it cannot be used for a portion that comes into contact with food or the like that is not preferable to be mixed. In addition, it is impossible to detect a deterioration state caused by aging of the rubber member, micro cracks, or the like.

  The deterioration diagnosis method described in Patent Document 3 only determines deterioration of a rolling surface of a tire or a support roller based on measured hardness.

  Also, in general, the life of rubber members is whether or not cracks or defects are formed on the surface, whether or not carbon adheres by touching with a finger, or whether or not elasticity is lost by pressing with a finger. I try to judge it.

  However, with the methods described in Patent Documents 1 and 2, or general methods, the degree of deterioration of the rubber member can only be qualitatively determined, and it is necessary to rely on experience and intuition. Further, when it is determined in this way, the replacement time may have already been reached, and it may be necessary to stop the operation of the apparatus using the rubber member. In addition, in the above-mentioned state, there is a possibility that a part of the rubber member has already dropped off or foreign matters (residues etc.) are mixed in the cracked part, so that germs can propagate and cause spoilage. Not suitable for use in. For this reason, conventionally, it has been desired to know the replacement time in a planned manner in advance.

  In addition, although the method described in Patent Document 3 can quantitatively determine the deterioration state of the rolling surface of the tire or the support roller, it can be used internally such as a female screw type stator used in a uniaxial eccentric screw pump. The deterioration state cannot be detected. In this case, the progress of deterioration greatly varies depending on the type and temperature of the fluid passing through the inner hole of the female screw type stator, but it is impossible to cope with this method.

JP 2000-221772 A JP 2005-36914 A Japanese Patent No. 3280718

  The present invention provides a single-shaft eccentric screw pump that can determine an internal deterioration state that cannot be directly measured while taking into consideration the influence of the temperature of the fluid to be conveyed, and can indicate an appropriate replacement time before reaching the end of its service life. It is an object of the present invention to provide a deterioration diagnosis method and apparatus for a female screw type stator to be used.

As a means for solving the above problems, the present invention provides:
An internally threaded stator having an inner hole and having a first axis, and a second axis that is disposed in the internally threaded stator and is eccentric from the first axis is around the first axis. A deterioration diagnosis method for a female screw type stator used in a uniaxial eccentric screw pump comprising a male screw type rotor that revolves in sliding contact with the female screw type stator,
A hardness measuring step for measuring the hardness of the female thread type stator;
When the hardness measured in the hardness measurement step belongs to a range equal to or less than the first set value, it is determined that it is a safe region, and a range from the first set value to a second set value larger than the first set value. An area determination step of determining that it is a caution area, and determining that it is an exchange area if it belongs to a range larger than the second set value;
Have
In the hardness measurement step, when the temperature is higher than a predetermined temperature based on the temperature of the fluid flowing through the inner hole of the female screw type stator, the end on the downstream side in the flow direction among the both ends of the female screw type stator When the hardness of the part is measured and lower than a predetermined temperature set in advance, the hardness of the central part of the female thread type stator is measured,
In the deterioration determination step, it is determined which region belongs to the hardness based on the hardness estimated in the hardness measurement step.

  According to the deterioration diagnosis method, it is possible to quantitatively determine the deterioration state of the female screw type stator by merely measuring the hardness of the female screw type stator and determining which region the hardness belongs to. Moreover, the position for measuring the hardness of the female thread type stator is changed according to the temperature of the fluid. As a result, it is possible to measure the hardness at the place where the deterioration is most likely to proceed and to determine the replacement timing of the female screw type stator at an early stage.

  In the area determining step, when belonging to a range from the second set value to a third set value greater than the second set value, it is determined that the area is a replacement area and belongs to a range greater than the third set value Therefore, it is preferable to determine that this is the use limit region.

  According to this method, it is possible to prompt the replacement before the deterioration state of the internal thread type stator is excessively deteriorated by determining the replacement time more finely.

  In the deterioration determination step, the hardness of a corresponding portion in the inner hole of the female screw type stator is estimated based on the hardness measured in the hardness measurement step, and which region belongs to the region based on the estimated value. It is preferable to judge.

  According to this method, it is possible to determine the deterioration state based on the hardness at the location that is assumed to be most easily deteriorated by being directly affected by the fluid, and to appropriately determine the replacement timing of the female screw type stator. Is possible.

  In the deterioration determination step, it is preferable to change each set value according to a difference in the interference between the female screw type stator and the male screw type rotor.

  According to this method, since it is possible to perform the deterioration determination in consideration of the difference in the interference between the female screw type stator and the male screw type rotor determined in consideration of the type of fluid, the replacement of the female screw type stator can be further performed. It becomes possible to determine the time appropriately.

Further, the present invention provides a means for solving the above-described problems,
An internally threaded stator having an inner hole and having a first axis, and a second axis that is disposed in the internally threaded stator and is eccentric from the first axis is around the first axis. A deterioration diagnosis device for a female screw type stator used in a uniaxial eccentric screw pump used in a uniaxial eccentric screw pump provided with a male screw type rotor that revolves in sliding contact with the female screw type stator,
The female threaded stator is formed by integrating a metal outer cylindrical body on the outer peripheral portion of the inner cylindrical body, and has a through hole that reaches the female threaded stator at either one or both ends of the outer cylindrical body. Part is formed,
Hardness measuring means attached to the mounting portion and measuring the hardness of the female thread type stator through a through hole;
Based on the temperature of the fluid flowing through the inner hole of the female screw type stator, when the temperature is higher than a predetermined temperature, the hardness of the end of the female screw type stator on the downstream side in the flow direction is measured. When the hardness is lower than a predetermined temperature set in advance, based on the hardness measured at the central portion of the female thread type stator, when the hardness belongs to a range equal to or lower than the first set value, it is determined to be a safety region. If it belongs to the range from the first set value to the second set value that is larger than the first set value, it is determined that it is a caution area and belongs to the range that is larger than the second set value from the second set value. A deterioration determining means for determining that the area is an exchange area;
It is set as the structure provided with.

  According to the present invention, the position of measuring the hardness of the female screw type stator is changed in consideration of the temperature difference of the fluid conveyed through the inner hole of the female screw type stator. It is possible to accurately grasp the state of the part considered to be advanced. Therefore, the female threaded stator can be replaced at the most appropriate time.

It is a schematic sectional drawing of the uniaxial eccentric screw pump concerning this embodiment. It is a front view of the hardness meter for measuring the hardness of the internal thread type stator of FIG. It is a schematic sectional drawing which shows the state which attached the hardness meter to the uniaxial eccentric screw pump of FIG.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In the following description, terms indicating specific directions and positions (for example, terms including “up”, “down”, “side”, “end”) are used as necessary. In order to facilitate understanding of the invention with reference to the drawings, the technical scope of the present invention is not limited by the meaning of these terms. Further, the following description is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a uniaxial eccentric screw pump according to this embodiment. This uniaxial eccentric screw pump includes a female screw type stator 1 and a male screw type rotor 2.

  The internal thread type stator 1 has a configuration in which an inner cylinder 4 made of a synthetic resin material (for example, Teflon (registered trademark), polyacetal, cast nylon, etc.) is integrated with an inner surface of an outer cylinder 3 made of a metal material. An opening 5 penetrating the inner peripheral surface is formed on the outer peripheral surface of one end side and the central portion of the outer cylindrical body 3, and the hardness of the inner cylindrical body 4 can be measured by a hardness meter 6. The inner cylinder 4 has two female screw-shaped inner holes 7. The inner hole 7 has an elliptical cross-sectional shape. The center of the inner hole 7 at the opening portion of both end faces of the inner cylindrical body 4 is located at the axial center (first axial center O1) of the female screw type stator 1.

  The male screw type rotor 2 is formed by forming a metal material such as stainless steel (for example, SUS304) or a synthetic resin material into a single male screw shape, and is mounted in the inner hole 7 of the female screw type stator 1. The interference of the externally threaded rotor 2 with respect to the internal diameter of the internally threaded stator 1 is changed according to the type of fluid to be conveyed. For example, in the case of a fluid such as juice that has a low viscosity, the interference is increased. Moreover, if it is a highly viscous fluid such as a paste, the interference is reduced. The vertical cross-sectional shape of the male screw type rotor 2 is substantially a perfect circle, and the pitch of the helical shape is ½ of the pitch of the inner holes 7 of the female screw type stator 1. A drive shaft 10 is connected to one end of the male screw type rotor 2 via a universal joint 8 and a coupling rod 9 so that a driving force from a motor (not shown) is transmitted. The rotation center (second axis O2) of the male screw type rotor 2 is eccentric from the first axis O1 of the female screw type stator 1. Thus, when the motor is driven, the male screw type rotor 2 rotates around the second axis O2 while revolving around the first axis O1.

  One end of the female thread type stator 1 is disposed at one end of a casing 11 in which the universal joint 8 and the like are accommodated. That is, a recess is formed in one end surface of the casing 11, and one end of the female screw type stator 1 is positioned in this recess. An end stud 12 is attached to the other end of the female thread type stator 1. The end stud 12 and the internal thread type stator 1 are attached to the casing 11 by connecting the end stud 12 and the casing 11 with a stay bolt (not shown) while sandwiching the internal thread type stator 1.

  In the single-shaft eccentric screw pump having the above-described configuration, a rotational force is applied from the drive shaft 10 to the male screw type rotor 2 via the coupling rod 9 and the universal joint 8 by driving the motor. The male screw type rotor 2 revolves around the first axis O1 of the female screw type stator 1 and rotates around the second axis O2. As a result, the fluid is sucked into the casing 11 and discharged from the end stud 12.

  When the fluid is conveyed using the uniaxial eccentric screw pump in this way, the deterioration of the female thread type stator 1 starts due to various factors. If the deterioration state of the internal thread type stator 1 becomes severe, there is a possibility that a crack may occur or a part of the internal thread type stator 1 may fall off. For this reason, if the fluid is directly related to the human body such as food and cosmetics, it is desirable to replace the female thread type stator 1 in advance.

  Therefore, the hardness of the inner cylinder 4 is measured by the hardness meter 6 through the opening 5 formed in the outer cylinder 3 of the female thread type stator 1 periodically. In this case, the measurement position is changed according to the temperature of the fluid. That is, the fluid conveyed by the uniaxial eccentric screw pump is conveyed at various temperatures through the inner hole 7 of the female screw type stator 1 depending on the type of the fluid.

  When a fluid at a high temperature (when the temperature of the fluid is higher than the air temperature around the uniaxial eccentric screw pump) is conveyed, the casing 11 and the end stud 12 made of a metal material become hot, and rubber or synthetic resin The internal thread type stator 1 made of the material continues to be affected by heat. For this reason, in the inner hole 7 of the female thread type stator 1, both end portions are more likely to deteriorate than the center portion. In particular, the end stud 13 side is the free end side of the male screw type rotor 2, and the deflection range of the male screw type rotor 2 increases with the deformation of the inner hole 7, and deterioration due to wear tends to proceed. On the other hand, when a fluid having a low temperature (when the temperature of the fluid is lower than the temperature of the air around the uniaxial eccentric screw pump) is conveyed, deterioration tends to proceed at the center of the inner hole 7.

  Therefore, when the temperature of the fluid is higher than the air temperature around the uniaxial eccentric screw pump, the hardness is measured at the tip of the female screw type stator 1, and when it is low, the hardness is measured at the center. Thereby, the hardness of the site | part considered that deterioration has progressed most can be measured. In this case, since the hardness at the outer peripheral portion of the female thread type stator 1 is measured, the hardness in the inner hole 7 is predicted from the measured value. Thereby, the hardness of the site | part which begins to start deterioration can be obtained. Here, a value obtained by uniformly adding a predetermined value (here, Shore hardness 2Hs) to the measured value is used as the estimated value.

  If the hardness in the inner hole 7 is estimated, it is determined to which region the hardness belongs. Here, on the scale of the hardness meter 6, the range of Shore hardness 65-75Hs is displayed as a green band as a safety area, and the range of 75-80Hs is displayed as a yellow band as a warning area. , 80 to 100 Hs (maximum scale) is displayed as a red band as an exchange area. In this case, since the hardness of the outer peripheral portion of the female thread type stator 1 is measured and the hardness in the inner hole 7 at the corresponding location is estimated, the position of the region described on the scale of the hardness meter 6 is estimated. It is preferable to make adjustments such as shifting in accordance with.

  The setting of the area based on the Shore hardness is merely an example, and the area may be freely changed to an appropriate value depending on the material used for the internal thread type stator 1. In this case, the relationship between the hardness measured in an experiment or the like and the deterioration state of the female thread type stator 1 may be obtained.

  In this way, the user can easily grasp the degree of deterioration of the female thread type stator 1 simply by measuring the hardness of the female thread type stator 1 with the hardness meter 6. In particular, when a food is transported as a fluid, if it is replaced when it becomes a caution area, it is possible to reliably prevent foreign matters from being mixed into the food, which is safe. Moreover, since the position of the internal thread type stator 1 measured by the hardness meter 6 is changed according to the temperature of the fluid to be conveyed, the hardness at a more preferable position can be measured, and the deterioration state can be accurately grasped. It becomes possible to do.

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

  In the above embodiment, the hardness of the female screw type stator 1 is measured through the opening 5 formed in the outer cylindrical body 3 of the female screw type stator 1, but each component is disassembled and the end face of the female screw type stator 1 is disassembled. The hardness may be measured.

  Specifically, in the case of transporting food, the fluid flow path of the fluid is cleaned frequently (every day). Therefore, at the time of this disassembly, the hardness of the end face of the internal thread type stator 1 (inner cylinder 4) is measured by the hardness meter 6. If measured at the end face of the inner cylinder 4, the hardness at a position closer to the inside of the inner hole 7 can be obtained compared to the case of measuring at the outer peripheral face, and the replacement time can be accurately determined. .

  Moreover, in the said embodiment, although the area | region determined from the hardness of the internal thread type | mold stator 1 was set to three, it is good also considering a replacement | exchange area | region as 80-90Hs of Shore hardness, and 90-100Hs as a warning area | region. That is, by indicating the limit value of the replacement region, it is possible to use the internal thread type stator 1 to the limit that is close to the actual life.

  Moreover, in the said embodiment, although the hardness of the internal thread type | mold stator 1 was measured suitably, as shown in FIG. 3, you may enable it to always measure, with the hardness meter 6 mounted | worn. In this case, it is possible to automatically record how the hardness of the internal thread type stator 1 changes over time, and to predict when the replacement time will be. In addition, it is preferable to correct the replacement time according to the interference between the female screw type stator 1 and the male screw type rotor 2. That is, it is considered that the larger the interference is, the faster the internal thread type stator 1 is deteriorated. Therefore, the predicted replacement time is corrected earlier.

  Further, even when the hardness is measured as appropriate, a change in the hardness of the internal thread type stator 1 is measured in advance by experiments or the like, and based on the measured value, to what extent the deterioration is currently progressing. You may make it understandable.

DESCRIPTION OF SYMBOLS 1 ... Female thread type stator 2 ... Male thread type rotor 3 ... Outer cylinder body 4 ... Inner cylinder body 5 ... Opening part 6 ... Hardness meter 7 ... Inner hole 8 ... Universal joint 9 ... Coupling rod 10 ... Drive shaft 11 ... Casing 12 ... End stud

Claims (5)

An internally threaded stator having an inner hole and having a first axis, and a second axis that is disposed in the internally threaded stator and is eccentric from the first axis is around the first axis. A deterioration diagnosis method for a female screw type stator used in a uniaxial eccentric screw pump comprising a male screw type rotor that revolves in sliding contact with the female screw type stator,
A hardness measuring step for measuring the hardness of the female thread type stator;
When the hardness measured in the hardness measurement step belongs to a range equal to or less than the first set value, it is determined that it is a safe region, and a range from the first set value to a second set value larger than the first set value. An area determination step of determining that it is a caution area, and determining that it is an exchange area if it belongs to a range larger than the second set value;
Have
In the hardness measurement step, when the temperature is higher than a predetermined temperature based on the temperature of the fluid flowing through the inner hole of the female screw type stator, the end on the downstream side in the flow direction among the both ends of the female screw type stator When the hardness of the part is measured and lower than a predetermined temperature set in advance, the hardness of the central part of the female thread type stator is measured,
A deterioration diagnosis method for a female screw type stator used for a single-shaft eccentric screw pump, wherein in the deterioration determination step, it is determined which region belongs based on the hardness estimated in the hardness measurement step.   In the area determining step, when belonging to a range from the second set value to a third set value greater than the second set value, it is determined that the area is a replacement area and belongs to a range greater than the third set value The deterioration diagnosis method for a female screw type stator used in a uniaxial eccentric screw pump according to claim 1, wherein the deterioration determination method is a use limit region.   In the deterioration determination step, the hardness of a corresponding portion in the inner hole of the female screw type stator is estimated based on the hardness measured in the hardness measurement step, and which region belongs to the region based on the estimated value. 3. A method for diagnosing deterioration of an internal thread type stator used in a uniaxial eccentric screw pump according to claim 1 or 2, wherein the determination is performed.   4. The single-shaft eccentric screw pump according to claim 1, wherein in the deterioration determination step, each set value is changed in accordance with a difference in interference of the female screw type stator and the male screw type rotor. 5. Deterioration diagnosis method for female thread type stators used in the process. An internally threaded stator having an inner hole and having a first axis, and a second axis that is disposed in the internally threaded stator and is eccentric from the first axis is around the first axis. A deterioration diagnosis device for a female screw type stator used in a uniaxial eccentric screw pump used in a uniaxial eccentric screw pump provided with a male screw type rotor that revolves in sliding contact with the female screw type stator,
The female threaded stator is formed by integrating a metal outer cylindrical body on the outer peripheral portion of the inner cylindrical body, and has a through hole that reaches the female threaded stator at either one or both ends of the outer cylindrical body. Part is formed,
Hardness measuring means attached to the mounting portion and measuring the hardness of the female thread type stator through a through hole;
Based on the temperature of the fluid flowing through the inner hole of the female screw type stator, when the temperature is higher than a predetermined temperature, the hardness of the end of the female screw type stator on the downstream side in the flow direction is measured. When the hardness is lower than a predetermined temperature set in advance, based on the hardness measured at the central portion of the female thread type stator, when the hardness belongs to a range equal to or lower than the first set value, it is determined to be a safety region. If it belongs to the range from the first set value to the second set value that is larger than the first set value, it is determined that it is a caution area and belongs to the range that is larger than the second set value from the second set value. A deterioration determining means for determining that the area is an exchange area;
An apparatus for diagnosing deterioration of an internal thread type stator used in a single-shaft eccentric screw pump.

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