KR101781267B1 - Positive displacement pump - Google Patents

Abstract

(For example, an inner member) 20 for transferring a fluid in accordance with a movement in the pump chamber 30, and a pump , And abnormal operation detecting means (40) for detecting an abnormal operation. The abnormality detection means 40 includes a sensor portion 41 for transmitting a microwave toward the motion member 20 and receiving the reflected wave therefrom and an abnormality detection means 40 for determining an abnormal operation based on a signal output from the sensor portion 41 And a judging section 42 for judging whether or not there is a defect. The sensor unit 41 is arranged to transmit and receive microwaves in a state where the fluid in the pump chamber 30 is interposed between the sensor unit 41 and the moving member 20. [ Thereby, a positive displacement pump capable of detecting an abnormal operation accurately and quickly is provided.

Description

[0001] POSITIVE DISPLACEMENT PUMP [0002]

The present invention relates to a positive displacement pump capable of detecting an abnormal operation.

In a positive displacement pump, fluid is transported along with movement (e.g., reciprocating motion or rotational movement) of a motion member (e.g., a piston or a rotor) in the pump chamber. The fluid to be transported may be, for example, a liquid. In the following description, the fluid to be transported is simply referred to as " fluid ".

In such a positive displacement pump, it is desired to detect an abnormal operation from the viewpoint of preventing wear and damage of the member. Abnormal operations include, for example, a ball operation, a completion operation, a closing operation, and foreign matter contamination.

The pneumatic operation means operation in a state in which the supply of fluid to the positive displacement pump is stopped due to the empty of the tank for supplying the fluid to the positive displacement pump and the fluid is almost or completely absent from the pump chamber. The state in which the fluid is hardly present in the pump chamber means, for example, the ratio of the volume (ml) of the fluid present in the pump chamber to the volume (ml) of the pump chamber is not more than several percent. In this case, gas (for example, air) in the tank may be introduced into the pump chamber instead of the fluid, and gas may exist in most or all of the pump chamber. Further, when gas is introduced into the pump chamber instead of the fluid, a part of the pump chamber is in a vacuum state, and the gas is present in the remaining portion. Such an idling operation also occurs when, for example, an abnormality occurs in the piping connected to the suction side of the positive displacement pump, or when an abnormality occurs in the device for supplying the fluid to the positive displacement pump.

Completion operation means operation in a state in which the volume of the fluid present in the pump chamber is reduced compared with that during normal operation. For example, the volume of the fluid in the pump chamber gradually decreases from the normal operation to the open operation.

The closing operation means a state in which a part of the fluid solidifies in a nozzle or a piping connected to the discharge side of the positive displacement pump and the operation in a state in which the flow path is narrowed or closed. Foreign matter incorporation means operation in a state where foreign matter is introduced into the pump chamber of the positive displacement pump together with the fluid.

Various proposals have conventionally been made for detection of abnormal operation of the positive displacement pump. For example, Patent Document 1 proposes a means for detecting an idle operation in a single-shaft eccentric screw pump. The cooperative operation detecting means comprises first and second cooperative operation detecting means. The first open-circuit detecting means receives a signal from the temperature detecting sensor of the stator (outer member), and judges that the stator is in the open operation when the temperature of the stator exceeds the set temperature. Further, the second open-circuit detecting means receives a signal from the temperature detecting sensor and judges that the stator is in the open operation when the temperature rise gradient of the stator exceeds the set temperature gradient.

Further, Patent Document 2 proposes a pump anomaly detection device. The abnormality detecting device detects the rotation torque of the motor and stores the same at regular intervals, calculates a comparison value as an average value, an upper limit allowable range for a comparison value, and a lower limit allowable range for a comparison value. Further, the average value is calculated from the rotation torque of the number of sets larger than the number of sets of the comparison value, and is used as the reference value. The permissible range for the reference value is determined from the upper-limit permissible range and the lower-permissible permissible range, and based on whether the comparison value is within the permissible range, it is determined that the pump is abnormal when the permissible range is not within the permissible range. As a result, the positional relationship between the stator and the rotor (inner member) changes due to wear of the stator, and a state in which the load acting on the motor for rotating the rotor is not stable can be detected abnormally.

Japanese Patent No. 4191857 Japanese Patent No. 5424202

As described above, in the positive displacement pump, it is desired to detect an abnormal operation. In Patent Document 1, a temperature sensor is disposed on a stator serving as an outer member, and a cooperative operation is determined based on the temperature rise of the stator.

However, since the stator is made of an elastic material such as rubber or a resin, its thermal conductivity is low. For this reason, it takes a time (for example, about 10 minutes) until the measured temperature of the temperature sensor rises after the state of the coarse operation, and the wear of the stator progresses during this time. Further, the temperature of the stator rises not only by the air operation but also by the increase of the number of revolutions of the rotor (inner member), the increase of the pump load, and the increase of the temperature of the fluid. When the temperature of the stator rises due to factors other than these pneumatic operations, it is judged as a pneumatic operation. In order to reduce the erroneous judgment, it is conceivable that a judgment is made as a cooperative operation when the temperature rise continues for a predetermined time by providing a delay timer or the like. However, if the delay timer is provided, the time required for detection of the empty operation is also increased.

Further, when the fluid is excellent in lubrication, even a cooperative operation, some fluid remaining in the stator acts as a lubricant, and the temperature rise of the stator tends to be suppressed. Therefore, in the case where the fluid is excellent in lubricity, there is a fear that the detection means described in Patent Document 1 may require time for detecting the air operation. Further, when the number of revolutions of the rotor is small, the heat radiation becomes larger than the frictional heat with the rotor in the stator. Therefore, the temperature of the stator does not change, and there is a fear that the detection means described in Patent Document 1 may require time for detection of the air operation.

In addition, the detection means disclosed in Patent Document 1 is intended for co-operation, and the clogging operation and foreign matter incorporation are not studied.

On the other hand, in the abnormality detecting device described in Patent Document 2, no examination has been made on the cooperative operation, the clogging operation, and foreign matter incorporation. It is also conceivable to apply the method of detecting an abnormality based on the torque of the motor disclosed in Patent Document 2 to the detection of the ball operation. Here, when the pump is idle, the torque of the motor temporarily rises and then rises. Temporarily reducing the torque of the motor is due to the reduction of the reaction force from the fluid. In this state, some of the fluid remaining in the stator acts as a lubricant. However, as the fluid in the stator decreases more and more due to the transfer of the fluid and the vaporization of the fluid due to the frictional heat, the torque of the motor is changed to the upward direction by the frictional force between the rotor and the stator.

In the change of the torque of such a motor, when it is judged as the idle operation at the step of temporarily reducing the torque, even when the torque temporarily decreases due to other factors, it is judged as an idle operation. The case where the torque temporarily decreases due to other factors includes, for example, a case where the torque temporarily decreases due to a change in the properties of the fluid, a change in the number of revolutions of the motor, and a change in a pipe (path) connected to the pump. On the other hand, when the air operation is judged at the step of increasing the torque of the motor, the torque rises after the torque temporarily decreases, so that it takes time to detect the coarse operation and the stator wear proceeds.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positive displacement pump capable of detecting an abnormal operation accurately and quickly.

The positive displacement pump according to an embodiment of the present invention includes a pump chamber, a motion member for transferring the fluid in accordance with the movement in the pump chamber, and an abnormal operation detecting means for detecting an abnormal operation. The abnormal operation detecting means includes a sensor portion for transmitting the microwave toward the moving member and for receiving the reflected wave and a judging portion for judging an abnormal operation based on the signal outputted from the sensor portion. The sensor unit is arranged to transmit and receive the microwave in a state in which the fluid in the pump chamber intervenes between the sensor unit and the motion member during normal operation.

Preferably, the judging section grasps the state of the fluid in the pump chamber together with the motion of the motion member based on the signal output from the sensor section.

The sensor unit preferably irradiates microwaves perpendicularly to the interface between the fluid and the pump chamber. It is preferable that the sensor unit always irradiate the microwave to the moving member.

It is preferable that the determination section determines either or both of the cooperative operation and the completion operation as the abnormal operation. And the judging section may adopt a configuration in which it is judged that the abnormal operation is performed when the peak value of the waveform of the signal exceeds the first threshold value. The determination unit may also be configured to determine the abnormal operation when the waveform of the signal is different from the predetermined pattern.

Preferably, the sensor unit comprises a Doppler type sensor. In this case, the judgment unit counts the number of occurrences of one or both of the mountains and valleys of the sinusoidal waves contained in the waveform of the signal, and when the number of occurrences counted within a predetermined time exceeds the second threshold value, It is possible to adopt a configuration in which it is determined that the operation is an operation. When the appearance frequency is used for the determination, the determination unit counts the frequency of appearance of the signal until the intensity of the signal exceeds the third threshold value and again until the intensity of the signal exceeds the third threshold value And increases the frequency of occurrence when the intensity of the signal exceeds the fourth threshold value. The third threshold may be set so as to detect only the peak or the valley of the sinusoidal wave outputted when the motion member is closest to the sensor unit.

In the case where the sensor unit is composed of a Doppler type sensor, the determination unit also adopts a configuration for calculating an integral value by integrating the waveform of the signal for a predetermined time and determining an abnormal operation based on the integral value .

Wherein the abnormal operation detecting means comprises: a signal processing unit for performing at least one of a high-pass filter, a low-pass filter, a full-wave rectification and an amplification to a signal output from the sensor unit, And an output unit for outputting a determination result of the determination unit.

It is preferable that the pump chamber is formed of an outer member whose inner circumferential surface is formed in an arm-threaded shape, and the motion member is an inner member of a screw thread type which relatively eccentrically rotates with respect to the outer member. In this case, the inner member of the outer member has a substantially elliptical shape in the transverse section, and the sensor unit transmits the microwave along a direction of the ellipse from a position on the symmetry line parallel to the elliptical direction of the substantially elliptical shape desirable. It is preferable that the sensor unit transmits the microwave to a portion of the inner member that always forms a closed space with the outer member.

In the present invention, the "approximately elliptical shape" is a shape in which the first arc-shaped portion 30c and the second arc-shaped portion 30d as shown in FIG. 2 (a) The shape is not limited to the following elliptical shape but may be a shape in which the first arc-shaped portion 30c and the second arc-shaped portion 30d as shown in FIG. 9A to be described later are connected to the curved portion 30g, And an elliptical shape as shown in Fig. 9 (b).

The positive displacement pump of the present invention directly grasps the state in the pump chamber by a sensor section that transmits and receives a microwave. Thereby, during abnormal operation, the output signal from the sensor section changes instantly, so that the abnormal operation can be detected quickly. In addition, when the fluid temperature rises, the abnormal operation is not erroneously determined, so that the abnormal operation can be accurately detected.

1 is a cross-sectional view schematically showing a configuration example of a positive displacement pump of the present invention.
Fig. 2 is a cross-sectional view schematically showing the movement of the rotor in the transverse section of the stator. Fig. 2 (a) c) shows a case where the rotation angle is 180 °, and Fig. 2 (d) shows when the rotation angle is 270 °.
3 is a schematic diagram showing an example of a waveform of a signal output from a Doppler type sensor.
Fig. 4 is a cross-sectional view schematically showing the state in the stator during normal operation. Fig. 4 (a) is the AA position of Fig. 1, Fig. 4 (b) is the BB position, Represents the state at the CC position.
Fig. 5 is a cross-sectional view schematically showing an example of a state in the stator in a cooperative operation. Fig. 5 (a) is the AA position in Fig. 1, and c) represents the state at the CC position, respectively.
6 is a schematic diagram showing a waveform example of a signal output from the pulse radar system and the FMCW system sensor.
Fig. 7 is a sectional view schematically showing a configuration example in the case where the positive displacement pump is a rotary pump.
8 is a cross-sectional view schematically showing an arrangement example of a sensor when the positive displacement pump is a single-shaft eccentric screw pump. FIG. 8 (a) And Fig. 8 (b) shows a case where the transmission direction is not perpendicular to the interface.
Fig. 9 is a schematic view showing an example of the cross-sectional shape of the inner circumferential surface of the outer member, Fig. 9 (a) showing a curved portion and Fig. 9 (b) showing an elliptical shape.
10 (a) is a cross-sectional view schematically showing a configuration example of a single-shaft eccentric screw pump in which an outer member is rotatable, FIG. 10 (a) Shows a case where the sensor unit is arranged in the outer rotor.
Fig. 11 is a schematic diagram showing an example of waveforms of signals including sine waves and valleys when a Doppler type sensor is used. Fig. 11 (a) Respectively.

Hereinafter, the positive displacement pump of the present embodiment will be described with reference to the drawings.

1 is a cross-sectional view schematically showing a configuration example of a positive displacement pump of the present invention. The positive displacement pump shown in Fig. 1 is a single axis eccentric screw pump 10. The single axis eccentric screw pump 10 includes an outer member 30 (hereinafter also referred to as a "stator") to be a pump chamber and an inner member 20 (hereinafter also referred to as an "inner rotor" Quot;). The stator 30 is an outer member, and the inner circumferential surface 30a thereof is formed in an arm thread shape. The rotor 20 is of a male thread type, receives power and eccentrically rotates. The rotor (20) and the stator (30) are housed in the casing (11). The casing (11) is a metal cylindrical member, and a first opening (11a) is formed at the tip end in the longitudinal direction. The first opening 11a functions as a discharge port of the single axis eccentric screw pump 10, and a nozzle, a pipe, and the like are mounted on the discharge port.

A second opening portion 11b is formed on the outer periphery of the casing 11. As shown in Fig. The second opening 11b is connected to the inner space of the casing 11 in the middle of the casing 11 in the longitudinal direction. The second opening 11b functions as a suction port of the single-shaft eccentric screw pump 10, and is connected to the tank through which the fluid is stored, for example, through a pipe.

The stator 30 is made of, for example, an elastic body such as rubber or a resin. The inner circumferential surface 30a of the stator 30 is n-thread female type and has one or a plurality of threads. On the other hand, the rotor 20 is a metal shaft. The rotor 20 is in the form of (n-1) male threads and has one or a plurality of threads.

In the single-shaft eccentric screw pump 10 shown in Fig. 1, the inner circumferential surface of the stator 30 has two sets of female threads, and has a plurality of threads. The cross-sectional shape of the inner peripheral surface of the stator 30 becomes an elliptical shape at any position in the longitudinal direction. On the other hand, the rotor 20 is in the form of a male screw eccentrically formed in a single set, and the cross section of the rotor 20 has a round shape at any position in the longitudinal direction. The rotor 20 is eccentrically rotatable in a state of being inserted into a space formed by the inner peripheral surface 30a of the stator 30.

The rotor 20 is connected to the rod 13 via the first material joint 12 and the rod 13 is connected to the second material joint 14 via the second material joint 14. In order to enable the rotor 20 to eccentrically rotate, And is connected to the shaft 15. Although not described in detail, the drive shaft 15 is rotatably held in the casing 11 in a state in which the gap with the casing 11 is sealed. The drive shaft 15 is connected to the main shaft 16a of the motor 16. As the main shaft 16a rotates by the operation of the motor 16, the drive shaft 15 rotates and rotates through the material joints 12 and 14 and the rotor 13 ) Eccentrically rotates.

When the rotor 20 is eccentrically rotated in this manner, the space defined by the rotor 20 and the inner circumferential surface 30a of the stator 30 advances in the longitudinal direction of the stator 30 while rotating within the stator 30. [ Therefore, it is possible to suck the fluid from the one end side of the stator 30 and to transfer the sucked fluid toward the other end side of the stator 30 for discharge. The uniaxial eccentric screw pump 10 shown in Fig. 1 can transfer the fluid sucked from the second opening portion 11b by rotating the rotor 20 in the forward direction to be discharged from the first opening portion 11a have.

Next, the motion of the rotor in the transverse section of the stator due to the eccentric rotational motion of the rotor will be described with reference to the drawings.

Fig. 2 is a cross-sectional view schematically showing the movement of the rotor in the cross-section of the stator. Fig. 2 (a) (c) shows the case where the rotational angle is 180 °, and FIG. 2 (d) shows the case when the rotational angle is 270 °. Fig. 2 is a sectional view taken along the line A-A in Fig. 2 (a) indicates the direction in which the sensor unit 41 transmits microwaves.

As shown in Fig. 2, the rotor 20 has a circular cross-sectional shape. The inner peripheral surface of the stator 30 has an elliptical cross-sectional shape, and the outer peripheral surface has a circular shape. The cross-sectional shape of the inner circumferential surface of the stator 30 has semicircular arcuate portions 30c and 30d connecting the opposite linear portions 30b and their end points. The cross-sectional shape of the inner circumferential surface has a symmetry line 30e parallel to the ellipse direction (the direction along the straight line portion 30b, see the hatched hatched portion in FIG. 2A) and a symmetry line 30e perpendicular to the ellipse direction. (See Fig. 2 (a)).

2 (a), the rotor 20 has a first arc-shaped portion 30c and a second arc-shaped portion 30c among the two arc-shaped portions 30c and 30d at the start (when the rotation angle is 0 °) It is in a tangible state. Hereinafter, this state is also referred to as " right stroke end ". In this case, when the rotor 20 starts eccentric rotation, the rotor 20 moves in the transverse section of the stator 30 toward the second arc-shaped portion 30d of the inner peripheral surface (ellipse) along the ellipse direction . When the rotation angle reaches 90 degrees, the first and second arc-shaped portions of the inner peripheral surface (ellipse) are located at the center of the arc-shaped portion as shown in Fig. 2 (b). When the rotational angle reaches 180 degrees, the second contact portion 30d comes into contact with the second arc portion 30d of the inner circumferential surface (ellipse) as shown in Fig. 2 (c). Hereinafter, this state is also referred to as " left stroke end ".

When the rotational angle reaches 180, the direction of movement of the rotor 20 is reversed. Thereafter, the rotor 20 moves toward the first arc-shaped portion 30c of the inner circumferential surface (oval) along the oval direction. When the rotation angle reaches 270 degrees, the first and second arc-shaped portions of the inner circumferential surface (ellipse) are positioned at the center of the arc-shaped portion as shown in Fig. 2 (d). When the rotation angle reaches 360 degrees, it is brought into a state of being in contact with the first arc-shaped portion 30c of the inner peripheral surface (ellipse) at the time of starting (Fig. 2 (a)).

Thus, the rotor 20 reciprocates in the space defined by the inner circumferential surface of the elliptical shape of the stator 30 in the transverse section. Further, the direction of the reciprocating motion is not limited to the left and right direction (horizontal direction) as shown in Fig. 2, but changes according to the arrangement direction of the pump. Further, even in the case of the same pump, the direction of the reciprocating motion changes in accordance with the position of the stator in the longitudinal direction (position in the transverse section).

The positive displacement pump of the present embodiment further includes means 40 for detecting an abnormal operation as shown in Fig. The abnormality detection means 40 includes a sensor unit 41 and a determination unit 42. The sensor unit 41 transmits the microwave toward the motion member (rotor) 20 and receives the reflected wave. The transmission and reception of the microwave by the sensor unit 41 is performed in a state in which the fluid in the pump chamber (stator) 30 is interposed between the sensor unit 41 and the moving member (rotor) 20 during normal operation . That is, the microwave passes through the fluid in the pump chamber (stator) 30 during the normal operation from the sensor portion 41 toward the motion member (rotor) 20.

The judging unit 42 judges abnormal operation based on the signal outputted from the sensor unit 41. [ The determination unit 42 shown in the figure is connected to the sensor unit 41 through a cable in order to receive a signal output from the sensor unit 41. [ The judging unit 42 judges whether or not the signal output from the sensor unit 41 is a radio communication signal by connecting the judging unit 42 to the radio receiver, .

Microwaves have a property of being reflected by a metal member, and transmittance is high for rubber, resin and the like. Therefore, it is not necessary to drill a hole in the stator 30 made of rubber or the like if the hole is made only in the casing 11 made of metal so as to reflect the microwave to the moving member and receive the reflected wave by the sensor unit 41 . Therefore, as shown in Fig. 1, the sensor portion 41 may be disposed in the through-hole formed in the casing 11. Fig.

However, depending on the material and the thickness of the stator 30 made of rubber or the like, the microwave is attenuated in the stator 30. In this case, for example, a hole having an appropriate depth may be formed in the stator 30 and the sensor portion 41 may be disposed in the hole. Thereby, the microwave can be reflected by the moving member, and the reflected wave can be received by the sensor unit 41.

In the case where the judging unit 42 receives a signal outputted from the sensor unit 41 by radio communication or the like, as in the configuration example of Fig. 10 to be described later, the inside of the stator 30 (outer member) The sensor portion 41 may be disposed inside the member disposed outside.

A Doppler type sensor, a pulse radar type sensor, or an FMCW type (continuous wave frequency modulation type) sensor may be employed as the sensor unit 41. [ Hereinafter, the detection of the abnormal operation in the case of using the sensors of the respective methods will be described.

3 is a schematic diagram showing a waveform example of a signal output from a Doppler type sensor. 3 shows the signal intensity on the vertical axis and the elapsed time on the horizontal axis. Fig. 3 shows the waveform of the signal intensity in the normal operation and the waveform of the signal intensity in the open operation (abnormal operation). An example of the waveform of the output signal shown in Fig. 3 is a waveform of the output signal when the Doppler type sensor is used in the configuration example shown in Fig. In the waveform example of the signal shown in Fig. 3, the signal outputted from the Doppler type sensor is subjected to the processing of the high-pass filter (the process of cutting the direct current component) and the process of the full wave rectification in that order.

A Doppler sensor for outputting a signal shown in Fig. 3 transmits and receives a microwave, and outputs a signal corresponding to a Doppler frequency. Here, the Doppler frequency is the difference between the frequency of the transmitted microwave and the frequency of the received microwave. More specifically, the Doppler sensor outputs a sinusoidal signal in accordance with the Doppler frequency, and the frequency of the signal changes in accordance with the Doppler frequency. In addition, the intensity (amplitude) of the signal changes in principle according to the energy of the reflected wave. However, when the Doppler frequency is 0 (zero), the intensity (amplitude) of the signal becomes 0 (zero) irrespective of the energy of the reflected wave.

In the case of using such a Doppler type sensor, in a normal operation, a portion with a signal strength of 0 and a portion with a sharp mountain-like shape appear alternately periodically. The portion where the signal intensity is flat and 0 indicates that the Doppler type sensor does not detect the moving body, that is, the microwave is absorbed by the fluid in the stator (pump chamber). More specifically, it indicates that the rotor (motion member) is located at a position other than the right stroke end, and shows a state as shown in (b) to (d) of FIG. This is because the microwaves are absorbed by the fluid as they enter the fluid in the stator (in the pump chamber) and advance, and can interfere with reaching the rotor (motion member) or reflections from the rotor (motion member).

The sharp mountain-shaped portion S indicates that the Doppler type sensor detects the moving body, that is, the microwave is reflected by the moving member without being absorbed by the fluid in the stator (pump chamber). More specifically, it indicates that the rotor is passing through the right stroke end as shown in Fig. 2 (a). This is because microwaves are not absorbed by the fluid in the stator (the pump chamber) and reach the rotor (motion member) because the rotor (motion member) and the stator (pump chamber) are in contact with each other at the right stroke end. Further, since the fluid interposed between the sensor portion and the rotor (moving member) is in a thin film shape both before and after the right stroke end, the microwave permeates the fluid in the stator (the pump chamber) to reach the rotor It is caused by being reflected.

In the case of using the Doppler type sensor, it is possible to grasp the state of the fluid in the pump chamber, that is, the fluid is filled in the pump chamber, based on the flat portion with the signal intensity of 0 in normal operation. Further, the motion (operation) of the motion member can be grasped based on the sharp mountain-shaped portion S.

Further, in a portion where the signal intensity is flat, a part of the transmitted microwave is reflected at the interface between the fluid and the stator (pump chamber), and the reflected wave is received. Since the frequency of the reflected wave is the same as the frequency of the transmitted microwave, the reflected wave is not reflected in the output signal.

On the other hand, in the open operation, the waveform of the signal changes. As shown in Fig. 3, the waveform of the signal has no portion where the signal intensity is zero and flat. That is, the Doppler sensor always detects the moving body (rotor). In the waveform of the signal shown in Fig. 3, a broad-acid-shaped portion B periodically appears, and a peak of the mountain-shaped portion B indicates that the rotor passes the right stroke end.

In addition, the peak value of the broad mountain-like portion B in the ball operation is larger than the peak value of the sharp mountain-shaped portion S in the normal operation. This is because the transmission and reception of the microwave by the sensor are not performed on the point that they do not have an area but are performed in a region having a constant area.

Fig. 4 is a sectional view schematically showing the state in the stator during normal operation. Fig. 4 (a) is the AA position in Fig. 1, Fig. 4 (b) is the BB position, ) Represents the state at the CC position, respectively. 1, the BB position and the CC position are slightly shifted from the AA position in the longitudinal direction of the rotor 20, the BB position is the first opening 11a side (discharge side), the CC position is the second (Suction side) on the side of the opening 11b.

4 (a), when the rotor 20 is positioned at the right stroke end, the fluid 60 is not interposed between the rotor 20 and the stator 30, (30) are in direct contact with each other. In this case, the microwave arrives at the rotor 20 and is reflected, and the reflected wave is received at the sensor unit 41. On the other hand, when the position is slightly shifted in the longitudinal direction of the rotor 20, a fluid intervenes between the rotor 20 and the stator 30 as shown in Figs. 4 (b) and 4 (c). In this case, the microwave is absorbed when advancing in the fluid 60, and it is possible to prevent the arrival of the microwave to the rotor 20 or the reflection of the microwave in the rotor 20. As a result, only the reflection wave at the A-A position is received by the sensor unit, and the energy of the reflected wave is weakened.

Fig. 5 is a cross-sectional view schematically showing an example of the state in the stator in the cooperative operation. Fig. 5 (a) is the AA position in Fig. 1, (c) show the state at the CC position, respectively. 5 (a) to 5 (c), no fluid is present in the stator 30 at any position. Therefore, regardless of the position in the longitudinal direction of the rotor 20, the microwave arrives at the rotor 20 and is reflected, and the reflected wave is received by the sensor unit 41. As a result, the energy of the reflected wave becomes strong.

In the case of using the Doppler type sensor, it is possible to grasp the state of the fluid in the pump chamber, that is, whether the fluid is mostly or completely not present in the pump chamber, based on the fact that the signal strength is 0 and the flat portion does not exist have. Further, the movement (motion) of the motion member can be grasped based on the broad mountain-shaped portion.

In the completion operation, the volume of fluid present in the pump chamber decreases. Therefore, as compared with the normal operation, the signal intensity is zero, the ratio of the flat portion decreases, and the ratio of the sharp-angled portion increases. Also, the peak value in the sharp mountain-shaped portion becomes large. Based on these, it is possible to grasp the state of the fluid in the pump chamber together with the motion of the motion member even in the completion operation.

In the closing operation, the fluid is excessively introduced into the stator (pump chamber). Therefore, in the right stroke end, the area of the region where the fluid intervenes between the stator and the rotor increases. Conversely, the area of the microwave-reflective area decreases. Therefore, the signal waveform changes and the peak value in the sharp mountain-shaped portion becomes smaller as compared with the normal operation. Based on this, it is possible to grasp the state of the fluid in the pump chamber together with the motion of the motion member even in the occlusion operation.

In the foreign matter incorporation, when a substance (for example, a metal) having a dielectric constant different from that of a fluid or a reflectance at the surface is mixed as a foreign matter, the signal waveform changes. As a foreign matter, for example, when a liquid having a dielectric constant smaller than that of a fluid is mixed, the absorption rate of the microwave decreases, thereby changing the signal waveform. Based on this, it is possible to grasp the state of the fluid in the pump chamber together with the motion of the moving member even in the presence of foreign matter.

6 is a schematic diagram showing an example of the waveform of a signal output from the pulse radar system and the FMCW system sensor. 6 shows the intensity of the signal output from the pulse radar system or the FMCW system sensor on the ordinate, and the elapsed time on the abscissa. Fig. 6 shows the waveform of the signal intensity in the normal operation and the waveform of the signal intensity in the open operation (abnormal operation). The waveform example of the output signal shown in Fig. 6 is a waveform of the output signal when the pulse radar system or the FMCW system sensor is used in the configuration example shown in Fig.

The pulse radar type sensor capable of outputting the signal shown in Fig. 6 transmits and receives microwave pulses and outputs signals corresponding to the time required from transmission to reception of microwave pulses. From this output signal, the distance between the sensor and the rotor (motion member) can be calculated.

The FMCW sensor transmits and receives a continuous wave of a microwave, and the frequency of the continuous wave changes in a predetermined period and shape. The FMCW sensor generates a bit signal obtained by mixing a reception signal and a transmission signal. From this output signal, the distance between the sensor and the rotor (motion member) can be calculated.

When such a pulse radar system and an FMCW system sensor are used, in a normal operation, as shown in Fig. 6, a portion C where the signal intensity changes and a portion where the signal intensity is constant appear alternately. The reason for this will be described below.

When the fluid in the stator (pump chamber) is not interposed between the sensor unit 41 and the motion member (rotor) 20 and is reflected by the motion member, specifically, as shown in Fig. 2 (a) In the case of the same right stroke end, a signal corresponding to the distance between the sensor portion and the rotor (motion member) is output from the sensor portion based on the reflected wave from the rotor (motion member). In the case where a thin-film fluid intervenes between the sensor unit 41 and the rotor (motion member) 20, specifically, in the case where the fluid is in front of or behind the right stroke end, And reaches the rotor. The microwave arriving at the rotor is reflected and reaches the sensor part. Therefore, based on the reflected wave from the rotor, a signal corresponding to the distance between the sensor part and the rotor is outputted from the sensor part. By this output signal at the right stroke end and before and after the right stroke end, a portion C in which the signal intensity changes appears. In addition, the waveform of the portion C in which the signal intensity varies is weak in the energy of the reflected wave, and it is likely to become unclear.

When a fluid having a predetermined thickness or more is interposed between the sensor part 41 and the rotor 20 (motion member), specifically, as shown in Figs. 2 (b) to 2 (d) When the distance between the rotor 41 and the rotor 20 is equal to or greater than a predetermined distance, the rotor is rotated by the fluid interposed between the sensor unit 41 and the rotor (the moving member) 20, ) Or reflection from the rotor (motion member). Therefore, a signal corresponding to the distance between the sensor and the fluid is outputted from the sensor based on the reflected wave at the interface between the fluid and the stator (pump chamber). By this output signal, a portion where the signal intensity is constant appears.

When the pulse radar system and the FMCW system sensor are used as described above, it is possible to grasp the state of the fluid in the pump chamber, that is, the fluid is filled in the pump chamber, based on the presence of the portion where the signal strength is constant. In addition, since the microwave arrives at the rotor at the right stroke end or before and after it, is reflected, and a signal based on the reflected wave is output from the sensor, the motion (operation) of the motion member can be grasped.

On the other hand, in the air operation, since gas is introduced into the stator (inside the pump chamber), no reflection occurs at the interface between the fluid and the stator (pump chamber). In addition, absorption of microwave by the fluid does not occur. From these, a signal based on the microwave reflected by the rotor (motion member) is outputted irrespective of the position of the rotor (motion member). That is, a signal corresponding to the distance between the sensor and the rotor (motion member) is output. Therefore, the waveform of the signal changes, and as shown in Fig. 6, the hill part and the valley part alternately appear.

When the pulse radar system and the FMCW system sensor are used in this way, the state of the fluid in the pump chamber, that is, the fluid in the pump chamber is mostly or completely absent . Further, the motion (motion) of the motion member can be grasped based on the alternate appearance of the hill and the valley.

In the completion operation, the volume of fluid present in the pump chamber decreases. Therefore, as compared with the normal operation, the ratio of the portion where the signal intensity is constant decreases, and the ratio of the portion where the signal intensity changes is increased. In addition, the peak value at the portion where the signal intensity changes is large. Based on these, it is possible to grasp the state of the fluid in the pump chamber together with the motion of the motion member even in the completion operation.

In the positive displacement pump of the present embodiment, the change of the waveform due to the abnormal operation is detected based on the signal output from the sensor unit in the determination unit, and the abnormal operation is determined.

Here, in the detection of the air operation based on the conventional temperature of the stator, the state in the pump chamber is indirectly grasped based on the temperature of the stator without directly grasping the state of the fluid in the pump chamber. Further, the detection of the abnormal operation based on the conventional motor torque indirectly grasps the state in the pump chamber based on the torque of the motor without directly grasping the state of the fluid in the pump chamber.

On the other hand, in the positive displacement pump of the present embodiment, the state of the fluid in the pump chamber can be directly grasped by the sensor unit 41. [ As a result, at the time of abnormal operation, as shown in Figs. 3 and 6, the output signal from the sensor unit changes immediately. Therefore, the abnormal operation can be detected quickly and can be detected within 5 seconds, for example.

Further, since the temperature of the stator (pump chamber) is not used when detecting the abnormal operation, when the fluid temperature rises, the abnormal operation is not erroneously determined. In addition, since the torque of the motor (the load of the drive unit) is not used when the abnormal operation is detected, in the case of a change in properties of the fluid, a change in the number of revolutions of the motor, There is no mistake because it is abnormal operation. Therefore, the positive displacement pump of the present embodiment can accurately detect the abnormal operation.

In the positive displacement pump of the present embodiment, the Doppler type sensor, the pulse radar type sensor, or the FMCW type (continuous wave frequency modulation type) sensor can be employed for the sensor portion 41. The frequency of the microwave transmitted by the sensor unit 41 may be, for example, 0.3 GHz to 3 THz.

The determination section 42 preferably grasps the fluid state in the pump chamber 30 along with the motion of the motion member 20 based on the signal output from the sensor section 41. [ When the motion of the motion member 20 is grasped, the number of revolutions and the like of the motion member can be obtained not only during abnormal operation but also during normal operation, for example. It is also possible to detect whether the motion of the motion member 20 is normal or abnormal by grasping the motion of the motion member 20. [ The abnormal operation of the motion member 20 corresponds to abnormal operation of the motion member due to, for example, breakage of the joint, defective motor, defective controller, or the like.

Further, when the positional relationship between the sensor portion and the motion member (rotor) changes at the stroke end due to abrasion of the motion member (rotor) or the pump chamber (stator), the signal may change accordingly. Concretely, it is conceivable that the peak value of the acid type becomes small, or the peak value can not be detected. By using this change in the signal, it is possible to detect wear of the motion member (rotor) or the pump chamber (stator). In addition, the present invention can be used for controlling the position of the moving member 20 at the time of stopping the pump. For example, the rotation angle of the rotor at the time of stopping the pump can be controlled to be constant.

Although the outer peripheral surface of the stator 30 (outer member) shown in Fig. 2 has a circular cross-sectional shape, the outer peripheral surface of the outer member may have a polygonal cross-sectional shape. Although the cross-sectional shape of the inner peripheral surface of the stator 30 (outer member) shown in Fig. 2 is an elliptical shape, the cross-sectional shape of the inner peripheral surface of the outer member may be a shape shown in Fig. 9 described later.

Fig. 9 is a schematic view showing an example of the cross-sectional shape of the inner peripheral surface of the outer member, Fig. 9 (a) showing a curved portion, and Fig. 9 (b) showing an elliptical shape. The cross-sectional shape of the inner peripheral surface of the outer member shown in Fig. 9A has the arc-shaped portions 30c and 30d of the first and second semicircular members similarly to the outer member shown in Fig. The cross-sectional shape of the inner circumferential surface of the outer member shown in Fig. 9A differs from that of the outer member shown in Fig. 2 in that the first arc-shaped portion 30c and the second arc- Shaped portion 30g. All of the curved portions 30g are convex inward, and the width W of the inner circumferential surface is narrowed along with the symmetry line 30f perpendicular to the elliptical direction. The curved portions 30g may be concave inward. In this case, the width W of the inner circumferential surface widens in the vicinity of the symmetry line 30f perpendicular to the elliptical direction.

The cross-sectional shape of the inner peripheral surface of the outer member shown in Fig. 9 (b) is an elliptical shape. When the cross-sectional shape is an elliptical shape, the elliptical direction is parallel to the long axis 30h, and the symmetrical line parallel to the elliptical direction is the long axis 30h.

1, the positive displacement pump is a single-axis eccentric screw pump in which the outer member is not rotatable. However, the positive displacement pump of the present embodiment is not limited to this type of single-axis eccentric screw pump. That is, the present invention can be applied to any displacement type pump having a pump chamber and a motion member capable of reflecting microwaves. For example, the outer member may be applied to a rotatable single-shaft eccentric screw pump, a rotary pump, a piston pump, or the like.

In the single-shaft eccentric screw pump in which the outer member is rotatable, an outer rotor is used instead of the stator as the outer member. Like the stator shown in Fig. 1, the outer rotor is made of an elastic material such as rubber or a resin, and the inner peripheral surface of the outer rotor has n pairs of female threads. Unlike the stator shown in Fig. 1, the outer rotor is rotatably held by, for example, a sliding bearing, a rolling bearing, or the like. More specifically, the outer rotor is fixed to an outer rotor casing made of metal, and the outer rotor casing is rotatably held by a bearing or the like. In this case, the outer rotor and the outer rotor casing rotate integrally.

Like the inner rotor 20 shown in Fig. 1, the inner rotor is a metal shaft, and is in the shape of male thread. Unlike the inner rotor 20 shown in Fig. 1, the inner rotor is rotatable, for example, by connecting the material joint and the rod directly to the main shaft of the motor without interposition. Further, in order to eccentrically rotate the inner rotor relative to the outer rotor, the rotation axis of the inner rotor is disposed at a predetermined distance from the rotation axis of the outer rotor.

In the single-shaft eccentric screw pump in which the outer member is rotatable, the inner rotor connected thereto is rotated by the rotation of the motor. The outer rotor rotates at half the number of revolutions of the inner rotor in a state in which the rotating shaft of the outer rotor and the rotating shaft of the inner rotor are eccentrically interlocked with the rotation of the inner rotor. In this way, the inner rotor rotates eccentrically relative to the outer rotor. In the single-shaft eccentric screw pump in which the outer member is rotatable, the inner rotor makes one round of the space of the substantially elliptical shape of the cross section of the outer rotor while the inner rotor (motor) rotates 720 degrees (two rotations).

Fig. 10 is a sectional view schematically showing a configuration example of a single-shaft eccentric screw pump in which an outer member is rotatable. Fig. 10 (a) shows a case in which the sensor unit is arranged in the outer rotor casing, ) Shows a case where the sensor unit is arranged in the outer rotor. The uniaxial eccentric screw pump shown in Figs. 10 (a) and 10 (b) includes a casing 11, a sliding bearing 18, an outer rotor casing 17, an outer rotor 31 , And an inner rotor (20). In the single-shaft eccentric screw pump in which the outer member is rotatable, the outer rotor 31 (outer member) becomes the pump chamber and the eccentricity of the outer rotor 31 relative to the outer rotor 31 The rotating inner rotor 20 becomes a moving member.

The uniaxial eccentric screw pump shown in Figs. 10 (a) and 10 (b) further includes an abnormal operation detecting means 40, similarly to the configuration example shown in Fig. The abnormality detection means 40 includes a sensor portion 41 and a determination portion 42. [ The judging unit 42 receives the signal outputted from the sensor unit 41 by wireless communication.

10 (a), the sensor portion 41 is disposed inside the outer rotor casing 17, more specifically, in the through hole formed in the outer rotor casing 17 . 10 (b), the sensor portion 41 is disposed inside the outer rotor 31, and more specifically, disposed in the non-through hole formed in the outer rotor 31 do. The sensor unit 41 integrally rotates with the outer rotor 31 and the outer rotor casing 17 in any of the configuration examples shown in Figs. 10 (a) and 10 (b).

7 is a cross-sectional view schematically showing a configuration example in the case where the positive displacement pump is a rotary pump. The rotary pump 50 shown in Fig. 7 includes a casing 51 and two rotors 52 having different rotational directions. In the rotary pump 50, the casing 51 serves as a pump chamber, and a metal-made rotor 52 that rotates becomes a moving member.

The rotary pump 50 shown in Fig. 7 further includes an abnormal operation detecting means 40, similarly to the configuration example shown in Fig. The abnormality detection means 40 includes a sensor portion 41 and a determination portion 42. [ In order to transmit and receive the microwave by the sensor unit 41, a through hole 51a is formed in the casing 51 made of metal. The rotary pump 50 has a seal member 53 for sealing the through hole 51a and a pressure plate 54 for pressing the seal member 53 against the casing 51. [ The seal member 53 is made of, for example, rubber permeable to microwaves.

The piston pump has, for example, a cylindrical cylinder and a piston. In such a piston pump, the cylinder serves as a pump chamber, and a piston reciprocating in the cylinder serves as a moving member.

The moving member is eccentrically rotated, rotated, or reciprocated. In at least a part of the movement process, the sensor unit can transmit the microwave toward the motion member.

8 is a cross-sectional view schematically showing an example of the arrangement of the sensor when the positive displacement pump is a single axis eccentric screw pump. FIG. 8 (a) is a view showing the transmission direction of the microwave of the sensor unit, And FIG. 8 (b) shows a case where the transmission direction is non-perpendicular to the interface. Fig. 8 corresponds to a cross-sectional view taken along the line A-A in Fig. 8 indicates the direction in which the sensor unit transmits microwaves.

The sensor unit can be arranged, for example, as shown in Figs. 8 (a) and 8 (b). In the case of the rotary pump, the sensor unit can be disposed at the position indicated by the arrow A in Fig. In this case, in a part of the movement process, the sensor unit can not transmit the microwave toward the motion member. However, with the motion of the moving member, a state in which the microwave is reflected by the moving member occurs periodically without intervening the fluid in the pump chamber between the sensor portion and the moving member. At that time, in the normal operation and the abnormal operation, the waveform of the output signal changes as described with reference to Figs. 3 and 6, so that the abnormal operation can be detected.

From the viewpoint of improving the detection efficiency of the abnormal operation, it is preferable that the sensor unit irradiates the microwave toward the motion member always during the motion process of the motion member. That is, it is preferable to dispose the sensor unit at a position where the motion member always reflects the microwave in a state in which the fluid in the motion member is not interposed between the sensor unit and the motion member. Concretely, it is preferable that the single-shaft eccentric screw pump as shown in Figs. 1 and 2 is disposed on one of the first and second arc-shaped portions 30c and 30d 2). It is preferable that the rotary pump as shown in FIG. 7 is disposed toward the rotation center of the rotor 52.

8 (b), microwaves can be irradiated to the interface between the fluid and the stator (pump chamber) in a direction not perpendicular to the interface between the fluid and the stator (pump chamber). However, as shown in Fig. 8 (a) , It is preferable that the microwave is irradiated perpendicularly to the interface between the sensor portion fluid and the stator (pump chamber). By arranging the sensor unit in this way, the transmission direction of the microwave of the sensor unit becomes perpendicular to the interface between the fluid and the pump chamber, and it is possible to prevent a part of the microwave from being refracted at the interface between the pump chamber and the gas or fluid in the pump chamber. High-intensity reflected waves can be received. In addition, it is possible to reduce the reflection of a part of the microwave at the interface between the pump chamber and the gas or fluid in the pump chamber, and thereby the high-intensity reflected wave can be received by the sensor unit.

More specifically, in the uniaxial eccentric screw pump as shown in Figs. 1 and 2, if the sensor portion is disposed on the side of the arc portions 30c and 30d, (30c, 30d). Further, if the sensor portion is disposed on the linear portion 30b side, it is preferable that the transmission direction of the microwave of the sensor portion is arranged parallel to the symmetry line 30f perpendicular to the elliptical direction.

The sensor unit is disposed at a position where the motion member always reflects the microwave, and the transmission direction of the microwave of the sensor unit is perpendicular to the interface between the fluid and the pump chamber, as shown in FIG. 2 (a) . Thereby, the detection efficiency of the abnormal operation can be improved, and the sensor unit can receive the high-intensity reflected wave.

The judging unit 42 detects at least one of an open operation, a completion operation, a closing operation, and foreign matter contamination as an abnormal operation. In the case of detecting an open operation, it may be applied to the end detection control. Here, the termination detection control is a control for stopping the pump when the delivery of the fluid is completed. When the air operation is detected, it is possible to realize the end portion detection control when it is determined that the delivery of the fluid is completed when the air operation is detected, and the pump is stopped. Further, when the completion operation is detected, the air operation can be prevented in advance in the case of reaching the air operation through the completion operation in the normal operation.

The determination of the abnormal operation can include, for example, a process of obtaining a waveform peak value of an output signal and a process of determining that the peak value exceeds an upper threshold value as an abnormal operation. The intensity of the output signal varies depending on, for example, the material of the stator or the seal member, its thickness, and the composition of the fluid to be conveyed. According to these conditions, the threshold value can be appropriately set.

The determination using the threshold value includes a mode in which the abnormality operation is determined when the peak value exceeds the threshold value and a mode in which the abnormality determination is made when the peak value is below the threshold value. Which type is employed can be appropriately set in accordance with the processing method of the output signal. In the case where the peak value exceeds the threshold value, the form of judging the abnormal operation is, for example, as shown in the waveform example shown in Fig. 3, by the processing of the high-pass filter (processing for cutting off the direct current component) Can be employed for the processing method of the output signal to be performed in that order. It is also possible to employ a method of performing the processing of the high-pass filter, the full-wave rectification, the low-pass filter, and the noninverting amplification in that order. On the other hand, when the peak value is less than the threshold value, the determination of the abnormal operation can be adopted, for example, in a method of performing the high-pass filter, the full-wave rectification, the low-

Further, the judging section 42 may judge the abnormal operation when the waveform of the output signal is different from the predetermined pattern. In this case, a waveform pattern of an output signal of normal operation is prepared in advance. When the abnormal operation is determined, a process of extracting a part of the output signal at a cycle similar to that of the predetermined pattern, a process of comparing the extracted waveform and the pattern waveform by the image analysis software, do. In the process of comparing and comparing the extracted waveform and the pattern waveform, for example, the waveform shape and area of the output signal can be used as a reference. The pattern using the pattern waveform and the pattern using the above-described threshold value may be performed in parallel.

Here, when feeding a fluid having a high viscosity (for example, paste, dehydrated cake, liver meat or the like), even if the pump is in a normal operation, the suction amount of the fluid is insufficient, . In this case, if the gas or vacuum portion is accidentally located on the path of the microwave, the microwave is hardly attenuated, so that the peak value temporarily changes. In a mode in which the peak value exceeds the threshold value is determined to be an abnormal operation, there is a possibility that the change is erroneously determined to be an abnormal operation.

Further, when a fluid (for example, a whipping cream) containing bubbles is fed, even if the bubbles are inadvertently positioned on the path of the microwave even in a normal operation, since the microwave is hardly attenuated, the peak value temporarily changes . In a mode in which the peak value exceeds the threshold value is determined to be an abnormal operation, there is a possibility that the change is erroneously determined to be an abnormal operation.

Incidentally, the Doppler sensor outputs a sinusoidal wave signal in accordance with the Doppler frequency as described above, so that the actual signal waveform includes the sine and valley of the sinusoidal wave. The cycle of the sinusoidal wave is shorter than the cycle of the reciprocating motion of the motion member (rotor). In the waveform example of the signal output from the Doppler sensor shown in FIG. 3, the sine and valley of the sinusoidal wave having a short cycle (microscopic) is omitted, and the cycle (Macroscopic) signal intensities are extracted and represented.

Fig. 11 is a schematic diagram showing an example of waveforms of signals including sine waves and valleys when a Doppler sensor is used. Fig. 11 (a) Respectively. The waveform example of the output signal shown in Fig. 11 is a waveform of the output signal when the Doppler type sensor is used in the example shown in Fig. The waveform example of the signal shown in Fig. 11 is a waveform of the signal outputted from the Doppler type sensor, in which the processing of the high-pass filter (processing for cutting off the direct current component), the processing for amplification and the processing for the low- In order.

In the normal operation, as described with reference to Fig. 3, a macroscopically flat portion where the body (rotor) is not detected and a mountain-shaped portion S that detects the body are alternately and periodically appear. The mountain-shaped portion S that detects the moving body indicates that the rotor is passing through the right stroke end. As shown in Fig. 11 (b), the mountain-shaped portion S that detects the moving body microscopically has the sine wave peaks P1 and P2 and the valleys T1. In Fig. 11 (b), the mountain-shaped portion S detecting the moving body is formed by two microscopic mountains P1 and P2 and one microscopic valley T1.

In the ball operation, as described with reference to Fig. 3, the Doppler type sensor always detects the moving body, so that a broad, mountain-shaped portion B periodically appears. The peak of the broad-acid-shaped portion B indicates that the rotor is passing through the right stroke end. The Doppler type sensor outputs a sinusoidal wave signal, and therefore, as shown in Fig. 11 (a), the broadband-shaped part B that detects the moving body is microscopically composed of a plurality of sinusoidal waves of a short period P1 to P7 and valleys T1 to T7. In Fig. 11A, a broad-acid-shaped portion B which detects a moving body is formed of seven microscopic acids P1 to P7 and valleys T1 to T7.

In the completion operation, although the illustration is omitted, the amount of fluid in the pump chamber is reduced, so that the range in which the rotor can be detected is wider (the distance becomes longer) as compared with the normal operation. Therefore, compared with the signal waveform of the normal operation shown in Fig. 11 (b), the signal waveform of the completion operation becomes shorter in the time when the flat portion without detecting the moving body appears, The time for appearance of the part S becomes long. Accordingly, microscopically, the number of mountains and valleys included in the mountain-shaped portion S detecting the moving body increases, and in the case shown in Fig. 11, the number of mountains and valleys increases to three or four, respectively .

The number of the waveforms of the signal including the sine and valleys of the sinusoidal wave may be used for the determination of abnormal operation. In this form, for example, a process of interpreting a signal waveform within a predetermined time range and counting the number of occurrences of one or both of the crests and valleys of the sinusoidal waves, and a process of counting the number of occurrences (hereinafter, ) Is judged to be an abnormal operation.

Here, as to a predetermined time (hereinafter also referred to as " evaluation time ") for setting the number of times of occurrence and a method of setting the threshold value for judgment, the single-shaft eccentric screw pump For example, As described above, the Doppler type sensor outputs a sinusoidal signal according to the Doppler frequency, and the Doppler frequency fd (Hz) can be approximated generally by the following expression (1).

fd = 2 x v x fs / c ... (One)

Where v is the speed of the moving body (m / s), c is the speed of light (about 3 x 10 ⁸ m / s), and fs is the frequency of the microwave transmitted (unit: Hz, hereinafter also referred to as "transmission frequency").

As described above with reference to Fig. 2, in the single-shaft eccentric screw pump in which the outer member is not rotatable, the rotor 20 (motor) rotates 360 degrees (one rotation) The space of the shape is made one round trip. The average velocity vr (m / s) of the rotor 20 at that time can be calculated by the following equation (2).

vr = 2 x s x N / 60 ... (2)

Here, s is the amount of stroke of the rotor (see Fig. 2 (a)), and N is the number of revolutions (min ^-1 ) of the motor.

In the waveform of the signal output by the Doppler type sensor, the number of occurrences A of the mountains or valleys (hereinafter also referred to as " the number of occurrences per cycle " hereinafter) Can be calculated by the following expression (3). Further, it is assumed that there is no attenuation of the microwave, that is, in a state of cooperative operation. Here, the time required for one cycle of movement means the time required for one reciprocation when the moving member reciprocates like a single axis eccentric screw pump, , It means the time required for one rotation.

A = 60 x fd / N ... (3)

Here, fd is the Doppler frequency (Hz), and N is the number of rotations of the motor (min ^-1 ).

If the Doppler frequency fd of the above equation (3) is substituted by the above equation (1) and the velocity v of the above equation (1) is replaced by the average velocity of the rotor of the equation (2) ) Is induced.

A = 4 x fs x s / c ... (4)

In the equation (4), the stroke amount s of the rotor is an intrinsic value of the pump, and the light flux c is a constant. Therefore, when the transmission frequency is kept constant, the frequency of occurrence (A) per cycle is constant without being affected by the number of revolutions of the motor. As in the case of the normal operation, the number of occurrences A per cycle is constant without being influenced by the number of revolutions of the motor or the like.

Therefore, the evaluation time may be appropriately set in accordance with the time required for the motion of one cycle of the motion member, such as the rotor 20, and more specifically, As shown in FIG. From the viewpoint of early detection of abnormal operation, the evaluation time is preferably short, and therefore, it is preferable to set the time necessary for one cycle of motion.

As shown in the above equation (4), the number of occurrences A per one cycle varies depending on the stroke amount (pump size) and the transmission frequency. The number of times of occurrence per evaluation time also varies according to the length of the evaluation time. According to these, the judgment threshold value may be appropriately set.

For example, according to the condition (s = 24 mm, fs = 24.2 GHz) of the signal waveform shown in FIG. 11, the number of times of occurrence A per one cycle becomes about 7.7 according to the expression (4). In the actual signal waveform, as shown in Fig. 11A, seven mountains (P1 to P7) and valleys (T1 to T7) were confirmed within one rotation time of the motor. In this case, if the time required for one cycle of motion is set as the evaluation time and the number of occurrences of either the acid or the valley is counted, the determination threshold may be set to any value between 3 and 6. [ For example, if the fluid to be conveyed is a fluid containing a high viscosity fluid or bubbles, the number of occurrences to be counted in the normal operation state increases, so that the determination threshold value may be set to a large value A (for example, 6) . If the fluid is a medium viscosity or low viscosity fluid and does not contain bubbles, the threshold for determination may be set to a value B (for example, 5) smaller than the value A.

If it is desired to detect the completion operation, the threshold value for judgment may be set to a value A or a value C (for example, 3 or 4) smaller than the value B for the open operation. When the completion operation is detected in this manner, the ball operation can be prevented in advance in the case of reaching the ball operation through the completion operation in the normal operation. A plurality of determination threshold values may be set. For example, it is possible to detect a plurality of abnormal operations, that is, a completion operation and a cooperative operation, by setting the threshold for determination to two levels of the value A or the value B of the cooperative operation and the value C of the completion operation.

Further, the amount of fluid in the pump chamber can be grasped based on the number of occurrences counted. For example, it is possible to estimate the amount of fluid in the pump chamber by comparing the counted number of occurrences with the number of occurrences counted in the open operation or the number of occurrences counted in the normal operation.

The coefficient of the occurrence count may be performed by increasing the number of occurrences when, for example, the intensity of the signal exceeds the threshold value V1 (hereinafter also referred to as " counting threshold value " in particular).

The evaluation time may be calculated from the number of revolutions of the motor. For example, if the outer member is a non-rotatable uniaxial eccentric screw pump, the time during which the motor makes one revolution can be set as the evaluation time. Further, when the outer member is a rotatable single-axis eccentric screw pump, the time for which the motor makes two revolutions can be set as the evaluation time.

Alternatively, the evaluation time may be defined by starting and ending the coefficient based on the waveform of the signal. In the mode of starting and ending the counting based on the waveform of the signal, a phenomenon in which the peak is deepest in the sine wave output when the moving member is the closest to the sensor portion is obtained.

In this embodiment, for example, a threshold value V2 (hereinafter, also referred to as a "threshold value for resetting") is set so as to detect only a peak or valley of a sinusoidal wave outputted when the motion member comes closest to the sensor unit . The process of replacing the number of occurrences by 0 (zero) when the intensity of the signal exceeds the reset threshold V2 and the process of increasing the number of occurrences when the intensity of the signal exceeds the count threshold V1 And a process of determining that the vehicle is in an abnormal operation when the number of occurrences exceeds the threshold for judgment. In the mode of starting and ending the counting based on the waveform of such a signal, the time required for one cycle of movement can be grasped more accurately and the detection accuracy of the abnormal operation can be increased.

In the process from normal operation to open operation, the integral value of the signal waveform changes as the number of sine waves and valleys included in the signal waveform changes. Here, the integral value of the signal waveform is obtained by integrating the signal waveform, and if it is the signal waveform shown in FIG. 11, the area of the region sandwiched between the horizontal axis and the signal waveform (curve) corresponds. The abnormal operation can also be detected based on the integral value.

In this embodiment, for example, when the integral value exceeds the threshold value, it is judged as an abnormal operation. More specifically, the abnormality determination process is performed by integrating the signal waveform within a predetermined time range to calculate an integral value, a process of determining that the integral value is smaller than that during normal operation as an obstruction operation, A process of determining that the operation is a completion operation when the integration value is slightly larger than that during the operation and a process of determining that the integration value is larger than that when the completion operation is performed is a common operation. When the integral value is used for the determination of the abnormal operation, the closing operation can be detected. In addition, the integral value (threshold value) serving as a reference of this determination can be appropriately set in accordance with conditions such as fluid composition, for example. In the above-described configuration example, all of the closing operation, the completion operation, and the air operation are determined, but one or more of them may be determined.

In a mode in which the abnormal operation is detected based on the integral value, the case where the integral value fluctuates irregularly may be determined as foreign matter incorporation. The process for determining the foreign matter incorporation may be performed together with the process for determining the closing operation, the completion operation, and the air operation described above. In the process for determining foreign matter incorporation, for example, a standard deviation may be calculated using a predetermined number of very close integration values, and when the standard deviation exceeds a threshold value, it may be determined as foreign matter incorporation. More specifically, the process of judging the foreign matter incorporation includes a process of sequentially storing the calculated integral values, a process of calculating a standard deviation by calling up a predetermined number of integration values very close to the stored integration value, It is judged that the foreign matter is foreign matter mixed. If an integral value is used in the determination of the abnormal operation, foreign matter contamination can be detected. The threshold value serving as a criterion for this determination can be appropriately set in accordance with conditions such as the composition of the fluid.

In the form of using the integral value of the signal waveform, the integral value is calculated by integrating the signal waveform for the predetermined time. This predetermined time (hereinafter also referred to as " integral processing time ") can be a time obtained by multiplying the time required for one cycle of motion by an integer, like the evaluation time of the form in which the number of times of occurrence is used for determination. From the viewpoint of early detection of the abnormal operation, the integral processing time is preferably short, and preferably is the time required for one cycle of motion. In this case, the integral processing time may be calculated from the number of revolutions of the motor, like the evaluation time, or the integral processing time may be defined by determining the starting point and the ending point based on the waveform of the signal.

The integral processing time may be set to be shorter than the time required for one cycle of motion. In other words, the integral value may be calculated by extracting a part from the waveform of the signal outputted in accordance with the motion of one cycle. For example, the integration processing time may be set to 1 / n of the time required for one cycle of motion. In this case, the starting position of the dispensing is set for each time when the time required for one cycle of motion is multiplied by an integer. Alternatively, if the signal waveform of FIG. 11 is used, only the peak of P1 and P2 in FIG. 11 (b) is sampled to calculate an integral value, and the integral of P1 and P7 in FIG. The integral value may be calculated by extracting only the part. This configuration can be expected to improve the detection accuracy of the clogging operation and foreign matter contamination. Further, the form using the integral value may be performed in parallel with the form using the above-described occurrence count.

It is preferable that the abnormal operation detecting means further includes a signal processing section 43 and an output section 44 and the judging section 42 judges abnormal operation based on the signal processed by the signal processing section 43 . Here, the signal processing unit 43 performs one or more processes of a high-pass filter, a low-pass filter, a full-wave rectification and an amplification on a signal output from the sensor unit 41. Further, the output unit 44 displays or outputs the determination result of the determination unit. The determination section 42, the signal processing section 43, and the output section 44 may transmit and receive signals via cables, respectively, and may transmit and receive signals by wireless communication.

The output unit 44 outputs, for example, the determination result to the controller of the positive displacement pump, and when the controller determines that the negative operation is performed, the positive displacement pump is stopped and a message is displayed on the display. Alternatively, the output section 44 may output the occurrence of the abnormal operation by operating the rotation or the like in the case of the abnormal operation. The output unit 44 may output a warning sound when it is determined that the operation is abnormal, thereby outputting the occurrence of an abnormal operation. With this output unit 44, the information of the detected abnormal operation can be utilized effectively.

The strength of the output signal varies depending on the material and thickness of the outer member or the seal member and the composition of the fluid to be conveyed as described above. By providing the signal processing unit 43, it is possible to absorb the change in the intensity of the output signal, and thus the abnormal operation can be stably detected. In addition, when the determination is made using a threshold value, the adjustment of the threshold value can be made unnecessary.

Preferably, the positive displacement pump is a single-shaft eccentric screw pump in which the outer member is non-rotatable or rotatable. In this case, the pump chamber is made up of an outer member (stator or outer rotor) having an inner peripheral surface formed in an arm-threaded shape, and the moving member is made of an inner member (rotor) of a screw thread type which eccentrically rotates relative to the outer member. In the case of a uniaxial eccentric screw pump, since the outer member is made of an elastic material such as rubber or a resin, it tends to wear during pneumatic operation, and the inner peripheral surface of the outer member may be pushed. This abrasion and pressing can be effectively prevented by the positive displacement pump of the present embodiment.

When the transverse sectional shape of the inner peripheral surface of the outer member 30 is substantially elliptic, as shown in FIG. 2, the sensor unit is a single-axis eccentric screw pump having an outer member in which the positive displacement pump is rotatable or non- It is preferable to transmit the microwave along the ellipse direction from the position on the symmetry line 30e parallel to the ellipse direction. This enables the rotor 20 of the motion member to always reflect the microwave while the fluid in the outer member 30 is not interposed between the sensor unit 41 and the rotor 20, The efficiency can be improved.

Further, it is possible to prevent a part of the microwave from being refracted at the interface between the outer member 30 and the fluid on the inner circumferential surface, and the reflected wave can be stably received by the sensor unit 41. Also, it is possible to reduce the reflection of a part of the microwave at the interface between the outer member 30 and the gas or the fluid in the outer member 30, whereby the sensor unit 41 can receive the reflected wave stably .

Here, the thickness of the outer member 30 changes in the circumferential direction, and the portion on the symmetry line 30e parallel to the elliptical direction becomes the thinnest. Therefore, if the sensor portion 41 is disposed on the symmetry line 30e parallel to the ellipse direction, the sensor portion 41 can be formed without forming a hole or the like for filling the sensor portion 41 in the stator 30, Can be easily installed.

It is preferable that the sensor unit 41 transmits the microwave to the portion where the closed space is always formed together with the outer member 30 in the rotor 20. [ That is, it is preferable that a space formed together with the outer member 30 in the rotor 20 is a microwave, except for a portion where the rotor 20 is temporarily opened in the eccentric rotational movement of the rotor 20. In the uniaxial eccentric screw pump shown in Fig. 1, the space formed by the portion from the both ends of the rotor 20 to the position where the thread number (number of stages) is 1.5 is temporarily set in the course of the rotation motion of the rotor 20 It becomes an open space. When the microwave is transmitted to the intermediate portion in the longitudinal direction of the rotor 20 except for the portions at both ends, the microwave is always transmitted to the portion forming the closed space.

The state of the fluid in the region tends to change depending on the situation of the upstream side and the downstream side of the rotor 20 at both end portions thereof and the state of the upstream side and the downstream side at the intermediate portion of the rotor 20 The change in the state of the fluid in the region tends to be mitigated. Therefore, the abnormal operation can be judged accurately.

INDUSTRIAL APPLICABILITY The positive displacement pump of the present invention can detect an abnormal operation accurately and quickly. Therefore, failure due to abnormal operation can be prevented, and as a result, the failure rate can be reduced and the operation rate can be greatly improved. Further, since the abnormality can be quickly notified, for example, when the positive displacement pump is used for applying the fluid in the production line, the defective rate of the subsequent process when the abnormality occurs can be reduced and the quality can be improved.

10: 1 axis eccentric screw pump (positive displacement pump) 11: casing
11a: first opening portion 11b: second opening portion
12: first material joint 13: rod
14: second material joint 15: drive shaft
16: motor (driving means) 16a: motor main shaft
17: outer rotor casing 18: sliding bearing
20: inner rotor (motion member)
30: stator (outer member, pump chamber)
30a: inner peripheral surface 30b: linear portion
30c: first shape portion 30d: second shape portion
30e: Symmetrical line parallel to the ellipse direction
30f: a line of symmetry perpendicular to the direction of the ellipse 30g:
30h: Long shaft 31: Outer rotor (outer member)
40: abnormal operation detecting means 41:
42: Judgment section 43: Signal processing section
44: output section 50: rotary pump
51: casing (pump chamber) 51a: through hole
52: rotor (motion member) 53: seal member
54: presser plate 60: fluid

Claims (15)

A positive displacement pump,
A pump chamber,
A motion member for transferring the fluid in accordance with the motion in the pump chamber,
And abnormal operation detecting means for detecting abnormal operation,
Wherein the abnormal operation detecting means comprises a sensor portion for transmitting a microwave toward the moving member and for receiving the reflected wave,
And a determination unit that determines an abnormal operation based on a signal output from the sensor unit,
Wherein the sensor unit is arranged to transmit and receive the microwave in a state in which the fluid in the pump chamber intervenes between the sensor unit and the moving member in normal operation. The method according to claim 1,
Wherein the determination unit grasps the state of the fluid in the pump chamber together with the motion of the motion member based on the signal output from the sensor unit. 3. The method according to claim 1 or 2,
Wherein the sensor unit irradiates the microwave perpendicularly to the interface between the fluid and the pump chamber. 3. The method according to claim 1 or 2,
Wherein the sensor unit always irradiates the microwave to the moving member. 3. The method according to claim 1 or 2,
Wherein the determination unit determines either or both of the cooperative operation and the completion operation as the abnormal operation. 3. The method according to claim 1 or 2,
Wherein the determination section determines that the abnormal operation is performed when the peak value of the waveform of the signal exceeds the first threshold value. 3. The method according to claim 1 or 2,
Wherein the judging section judges that the signal is abnormal when the waveform of the signal is different from a predetermined pattern. 3. The method according to claim 1 or 2,
Wherein the sensor unit is a Doppler type sensor. 9. The method of claim 8,
Wherein the judging section counts the number of occurrences of one or both of the crests and valleys of sinusoidal waves included in the waveform of the signal and judges that the abnormal operation is performed when the number of occurrences counted within a predetermined time exceeds the second threshold value A positive displacement pump. 10. The method of claim 9,
Wherein the judging unit counts the number of times the intensity of the signal exceeds the third threshold and again until the intensity of the signal exceeds the third threshold, Increasing the number of occurrences when the threshold value is exceeded,
And the third threshold value is set to detect only the mountain or valley of the sinusoidal wave outputted when the motion member is closest to the sensor unit. 9. The method of claim 8,
Wherein the determination unit calculates an integral value by integrating the waveform of the signal for a predetermined period of time and determines an abnormal operation based on the integral value. 3. The method according to claim 1 or 2,
Wherein the abnormal operation detecting means comprises: a signal processing section for performing at least one of a high-pass filter, a low-pass filter, a full-wave rectification and an amplification to a signal output from the sensor section,
And an output section for outputting a determination result of the determination section. 3. The method according to claim 1 or 2,
Wherein the pump chamber comprises an outer member whose inner circumferential surface is formed in a female screw shape,
Wherein the moving member is an inner member of a screw thread type that eccentrically rotates relative to the outer member. 14. The method of claim 13,
Wherein the outer member has an elliptical shape in its inner peripheral surface in a transverse section,
Wherein the sensor unit transmits the microwave along a direction of an ellipse from a position on a symmetry line parallel to the elliptical direction of the elliptical shape. 14. The method of claim 13,
Wherein the sensor unit transmits the microwave to a portion of the inner member that always forms a closed space together with the outer member.

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