JP4643171B2 - Sewage pump - Google Patents

Description

  The present invention relates to a sewage pump for pumping sewage discharged from a flush toilet or the like.

  In housing construction, water distribution pipes are installed only in the places included in the design drawing before the start of construction, and therefore the installation places such as flush toilets are limited. For this reason, it is impossible to change the installation position of flush toilets etc. due to subsequent changes in the family structure, remodeling of rooms, etc. For example, it is not possible to temporarily install flush toilets in rooms with sick people It was.

  Therefore, in recent years, retrofitting flush toilets have been proposed, and some of them have already been put into practical use. When installing this retrofitting flush toilet, etc., there is no drain pipe at the installation location, so it is necessary to forcibly drain the sewage from the flush toilet etc. with a small sewage pump. Several proposals regarding pumps have also been made (see, for example, Patent Documents 1 and 2).

  By the way, in the sewage pump used for flush toilets, in addition to the “motor” as a driving source, a “grinding section” composed of a cutter or a mixer for crushing or cutting sewage, toilet paper, etc. It is necessary to provide a “pump unit” composed of an impeller and a casing for draining the waste contaminated water later.

Japanese Patent Application No. 2002-297885 Japanese Patent Application No. 2003-262743

However, in the conventional sewage pump, for example, as shown in FIG. 6 , the cutter 123 and the impeller 129 are directly connected to the motor shaft 104 of the motor (M).

  That is, for example, when a handkerchief is accidentally dropped on a toilet bowl, the handkerchief or the like cannot be completely subdivided by the cutter 123. In the worst case, the rotation of the impeller 129 together with the cutter 123 may stop and the pump cannot be pumped.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sewage pump that can prevent the inability to lift water due to tangling of a handkerchief or the like.

In order to achieve the above object, a first aspect of the present invention provides a sewage pressure pump in which a cutter and an impeller are rotationally driven by a motor, and sewage containing foreign matter crushed by the cutter is pumped by the impeller. A first magnet coupling fixed to the shaft end of the first magnet and a second magnet fixed to the cutter side are opposed to each other in the motor axial direction through a partition wall or a thrust pad to constitute a first magnet coupling, and the motor A second magnet coupling is configured by causing a third magnet fixed to the other shaft end of the shaft and a fourth magnet fixed to the impeller side to face each other in the motor shaft direction via a partition wall or a thrust pad. the rotation of the motor shaft before via the first magnetic coupling and said second magnetic coupling With respectively transmitted to the cutter and the impeller, the driving torque from the motor to the cutter is set to be smaller than the driving torque to the impeller, a vibration sensor for detecting the step-out of the previous SL first magnet cup-ring The motor is incorporated in the motor.

According to a second aspect of the present invention, in the first aspect of the invention, the driving torque from the motor to the cutter is reduced by making the magnetic flux density of the second magnet smaller than the magnetic flux density of the fourth magnet. The driving torque for the impeller is set smaller than the driving torque .

The invention according to claim 3 is the invention according to claim 1, wherein the second magnet and the fourth magnet having the same magnetic flux density are respectively molded, and the mold depth of the second magnet is set to the fourth magnet. The driving torque from the motor to the cutter is set to be smaller than the driving torque to the impeller by making it deeper than the mold depth of the magnet .

The invention of claim 4, wherein, in the invention of claim 1, wherein, than the distance between the pair of magnets constituting the said distance between the pair of magnets constituting the first magnetic coupling second magnetic coupling The driving torque from the motor to the cutter is set to be smaller than the driving torque to the impeller .

According to the present invention, power transmission from the motor to the cutter and the impeller is performed via the first and second magnet couplings, and the driving torque from the motor to the cutter is set smaller than the driving torque to the impeller. Even when a foreign object such as a handkerchief gets entangled with the cutter and the rotation of the cutter is locked, the impeller continues to rotate and performs the required pump function, and the pumping of sewage continues to make pumping impossible. In addition, there is no problem such as sewage overflowing from the container. In addition, when a step-out phenomenon occurs in the first magnet coupling because of foreign matter such as a handkerchief entangled with the cutter, a large vibration is generated, but this vibration is detected by a vibration sensor. It is possible to know quickly and to issue appropriate alarms by issuing an alarm or the like.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a cross-sectional view of a sewage pump according to Embodiment 1 of the present invention.

  The sewage pump 1 according to the present embodiment is a pump for pulverizing sewage such as stool from a flush toilet and pumping sewage containing crushed sewage (sewage mixed water), from above a pulverizing unit (C ), A motor (M), and a pump unit (P). In this sewage pump 1, the motor case 2 constituting the housing of the motor (M) is composed of a case main body 2A and a cover 2B attached to the upper part of the case main body 2A. It is integrally formed. In this embodiment, a brushless DC motor is used as the motor (M).

  In the motor case 2, a motor shaft 4 is vertically arranged at the center thereof, and the motor shaft 4 is rotatably supported by a pair of upper and lower ball bearings 5. A rotor 6 is inserted into and fixed to the motor shaft 4, and a ring-shaped stator 7 that is a coil winding is disposed around the rotor 6. The substrate 8 in the motor case 2 is provided with a rotation sensor 9 composed of a Hall element and an ultra-small acceleration sensor 10. The rotation speed of the motor shaft 4 is detected by the rotation sensor 9, and vibration is detected by the acceleration sensor. 10 is detected. The stator 7 is connected to a lead wire 11 extending from a power source (not shown).

  By the way, drum-shaped magnet holders 12 and 13 are fixed to the upper and lower surfaces of the rotor 6 by a plurality of bolts 14 and nuts 15 screwed thereto. Magnets (permanent magnets) 16 and 17 formed in a ring shape by alternately arranging magnetic poles of S and S are fixed.

  On the other hand, short shafts 18 and 19 are provided coaxially and integrally with the motor shaft 4 on the upper portion (cover 2B) and lower portion (case body 2A) of the motor case 2, respectively. A resin mixer (cutter base) 21 is rotatably supported via a bearing bush 20. The mixer 21 is molded with a magnet (permanent magnet) 22 facing the magnet 16 through the cover 2B of the motor case 2, and a metal cutter 23 is provided on the upper surface of the mixer 21 with a plurality of screws. (Only one is shown in the figure) 24. Further, a ring-shaped thrust pad 25 is interposed between the cover 2B of the short shaft 18 and the mixer 21, and a downward thrust force acting on the mixer 21 and the cutter 23 (attraction force by the magnets 16 and 22). Is received by the thrust pad 25. The magnet 22 is formed in a ring shape by alternately arranging N-pole and S-pole magnetic poles in the same manner as the magnet 16, and the pair of magnets 16 and 22 constitutes a magnet coupling.

  Here, although the mixer 21 and the cutter 23 constitute a grinding part (C), they are housed in a cylindrical cutter case 27 attached to the upper part of the motor case 2 by a plurality of bolts 26, and are not shown. However, the cutter case 27 is formed with a plurality of small circular hole outlets 27b as well as one large circular hole inlet (not shown). A connecting pipe (not shown) extending obliquely downward from a toilet (not shown) is connected to the inlet (not shown).

  A resin impeller 29 is rotatably supported on the lower short shaft 19 via a bearing bush 28. The impeller 29 is supported via a case main body 2A (pump case 3) of the motor case 2. A magnet (permanent magnet) 30 facing the magnet 17 is molded. The short shaft 19 is provided with a pair of upper and lower thrust pads 31 and 32 in a ring shape so as to sandwich the impeller 29 from above and below. Force) is received by the thrust pad 31, and downward thrust force (water suction force) is received by the thrust pad 32. The lower thrust pad 32 is fixed by a snap ring 33 fitted to the end of the short shaft 19.

  Here, similarly to the magnet 17, the magnet 30 is formed in a ring shape by alternately arranging N-pole and S-pole magnetic poles, and the pair of magnets 17 and 30 constitutes a magnet coupling.

  The bearing bushes 20 and 28 are made of carbon-impregnated resin, and the thrust pads 25, 31 and 32 are made of zirconia or alumina ceramics.

  By the way, a bottom plate 34 is attached to the lower surface of the pump case 3 in the pump part (P) by a plurality of bolts 35 (only one is shown in FIG. 1), and the center of the impeller 29 is at the center part. A suction port 36 is formed in the part. A scroll-like pump chamber 37 is formed in the pump case 3, and the impeller 29 is rotatably disposed in the pump chamber 37. A discharge nozzle 3a protrudes from the side of the pump case 3, and a discharge port 38 is opened in the discharge nozzle 3a.

  Thus, the sewage pump 1 having the above configuration is housed in a container (not shown).

  Next, the operation of the sewage pump 1 according to the present invention will be described.

  Sewage from a toilet (not shown) flows into the sewage pump 1 in the container along the inclination of a connection pipe (not shown). In the sewage pump 1, the motor (M) is driven, and the rotation of the motor shaft 4 of the motor (M) is performed by magnet couplings configured by magnets 16, 22 and magnets 17, 30 facing each other. The signals are transmitted to the mixer 21, the cutter 23, and the impeller 29, respectively, and are rotated at a predetermined speed. That is, when the motor shaft 4 of the motor (M) is rotationally driven, the upper and lower magnets 16 and 17 are rotated with the motor shaft 4, and exist between the magnets 16 and 17 and the magnets 22 and 30 respectively facing them. Due to the principle of a general permanent magnet, an attractive / repulsive force is generated by the N / S poles in the circumferential direction between a pair of opposing magnets 16 and 22 and between the magnets 17 and 30. The rotation of the motor shaft 4 is transmitted to the mixer 21, the cutter 23 and the impeller 29, respectively, and these are rotated at a predetermined speed around the short shafts 18 and 19 as described above.

Incidentally, bearing bushes 20 and 28 are fitted to the respective rotation centers of the mixer 21, the cutter 23 and the impeller 29, and these bearing bushes 20 and 28 rotate around the respective short shafts 18 and 19. The sliding resistance is kept small. The thrust force acting on the mixer 21 and the cutter 23 is received by the thrust pad 25, and the thrust force acting on the impeller 29 is received by the thrust pads 31 and 32. Incidentally, since the cutter 23 only performs the crushing action and does not generate an upward thrust force (suction force), only one thrust pad 25 may be provided for the cutter 23 and the mixer 21.

  Here, when the transmission torque from the motor (M) to the cutter 23 is Tc, the transmission torque to the impeller 29 is Ti, and the driving torque Tm of the motor (M), the following magnitude relationship is established between them. It is configured.

Tm>Ti> Tc (1)
Tm ≧ Ti + Tc (2)
In this embodiment, the driving torque Tm of the motor (M) is set to about 150 W, the driving torque Tc to the cutter 23 is set to about 40 W, and the transmission torque Ti to the impeller 29 is set to about 100 W, respectively (1 ) And (2) are satisfied.

  By the way, as shown in the equation (1), as a method for making the driving torque Tc to the cutter 23 smaller than the transmission torque Ti to the impeller 29 (Tc <Ti), a method using magnets having different magnetic flux densities. (A magnet 22 having a magnetic flux density smaller than that of the magnet 30 is used.) When a magnet having the same magnetic flux density is used, a method of changing the mold depth thereof (the mold depth of the magnet 22 is changed from that of the magnet 30). (In the illustrated example, the right depth h of the magnet 22 is made deeper than the left depth h ′ (h> h ′))), between a pair of magnets constituting the magnet coupling A method of changing the distance (for example, a washer is interposed between the thrust pads 25 to change the distance between the magnets 16 and 22 to the magnets 17 and 3. It is set to be larger than a distance between) or the like.

Thus, as described above, when the cutter 23 rotates in the cutter case 27 and the impeller 29 rotates in the pump chamber 37 in the pump case 3, the cutter case 27 enters the cutter case 27 from the inlet opening in the side wall of the cutter case 27. Foreign matter such as stool contained in the sewage flowing into the sewage is finely pulverized by the cutter 23 and flows out into the container from the plurality of outlets 27b together with the sewage. The discharged sewage is sucked from the suction port 36 into the pump chamber 37 by the pumping action of the impeller 29 rotating in the pump chamber 37, and after being pressurized by the impeller 29, is discharged to the discharge port 38 of the discharge nozzle 3 a. Then, it is pumped to a sewage pipe (not shown) and a septic tank through a drain pipe (not shown) connected to the discharge nozzle 3a.

  By the way, if the handkerchief or the like is accidentally dropped into the toilet bowl, the handkerchief or the like cannot be cut by the cutter 23, so that the handkerchief or the like is entangled with the cutter 23 or the mixer 21, and the rotation of the cutter 23 and the mixer 21 is locked. Is done. Even in such a case, a magnetic coupling is used to transmit power from the motor shaft 4 to the cutter 23 and the mixer 21, and the driving torque Tc to the cutter 23 is applied to the impeller 29 as described above. Since the torque is smaller than the transmission torque Ti (Tc <Ti), the motor shaft 4 continues to rotate, and the magnet coupling composed of the magnets 17 and 30 functions normally and transmits the rotation of the motor shaft 4 to the impeller 29. As a result, even if the impeller 29 continues to rotate together with the rotating shaft 4 and the crushing function by the cutter 23 stops, at least the impeller 29 normally rotates and continues to pump sewage. Occurrence is avoided, and troubles such as overflow of sewage from the container do not occur.

When the rotation of the cutter 23 and the mixer 21 cannot be synchronized with the rotation of the motor shaft 4 due to the entanglement of a handkerchief or the like, and the so-called step-out phenomenon occurs, the repulsion between the same poles due to the N pole and the S pole occurs between the magnets 16 and 22. As a result, the transmission torque Tc to the cutter 23 becomes approximately 0 on average (Tc≈0). Further, when a step-out phenomenon occurs in the magnet coupling constituted by the doughnut-shaped magnets 16 and 22, a large vibration is generated due to the repulsion and attracting by the N pole and the S pole, and this vibration is caused by the acceleration sensor 10. Therefore, for example, an alarm is issued to notify the occurrence of the step-out phenomenon, and an appropriate measure can be promoted.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 2 is a cross-sectional view of the sewage pump according to the present embodiment. In FIG. 2, the same elements as those shown in FIG. 1 are denoted by the same reference numerals. Omitted.

  In the sewage pump 1 according to the present embodiment, the magnet 22 on the cutter 23 side has a large diameter, the magnet 16 on the motor M side facing the magnet 22 has a small diameter, and a rotation sensor is provided at a portion facing the magnet 22 on the substrate 8. 9 ′ is arranged, and the rotation of the cutter 23 is detected by detecting the change speed of the alternating magnetic force accompanying the rotation of the magnet 22 by the rotation sensor 9 ′. It is the same as that of Form 1.

  Thus, in the sewage pump 1 according to the present embodiment, when a step-out phenomenon occurs in the magnet coupling because of foreign matter such as a handkerchief entangled with the cutter 23, the rotation of the cutter 23 is decelerated. Alternatively, since this is stopped, the occurrence of an abnormality can be quickly known by detecting this with the rotation sensor 9 ′, and an appropriate measure can be promoted by issuing an alarm or the like.

<Embodiment 3>
Next, a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 3 is a cross-sectional view of the sewage pump according to the present embodiment, and FIG. 4 is an enlarged cross-sectional view of the cutter part and the impeller part of the sewage pump. The same elements as those in FIG.

The sewage pump 1A according to the present embodiment is a pump in which a motor (M), a pulverizing part (C), and a pump part (P) are arranged from the top. In this sewage pump 1A, a cutter case 27 is attached to the lower part of the motor case 2 constituting the housing of the motor (M), and the pump case 3 is formed integrally with the lower part of the cutter case 27. . A bottom plate 34 is attached to the lower end surface of the pump case 3, and a circular suction port 36 is opened at the center of the bottom plate 34.

  Further, a large circular hole inlet 27a and a plurality of small circular outlets 27b are formed on the side wall of the cutter case 27. The inflow port 27a is connected to a connection pipe (not shown) extending obliquely downward from a toilet (not shown).

  By the way, a motor shaft 4 is vertically arranged in the center of the motor case 2, and the motor shaft 4 is rotatably supported by a pair of upper and lower ball bearings 5. The motor shaft 4 passes through the center of the cutter case 27 and the pump case 3 and extends downward to the pump chamber 37, and an impeller 29 is attached to the lower end portion facing the pump chamber 37 by a nut 39. . In addition, the part (shaft penetration part) through which the motor shaft 4 penetrates the motor case 2 is sealed with the oil seal 40, respectively.

  Further, as shown in detail in FIG. 4, a sleeve 41 is inserted and fixed at the lower end of the portion of the motor shaft 4 facing the cutter case 27, and an inverted dish-shaped mixer ( A cutter base 21 is rotatably supported, and a cutter 23 is attached to the upper surface of the mixer 21 with a plurality of screws 24.

  Here, a donut ring-shaped magnet 16 is attached to the upper surface of the flange portion 41 a of the sleeve 41, and a similar magnet 22 is attached to the bottom surface of the mixer 21 above it. , 22 constitute a magnet coupling, and these are arranged opposite to each other in the motor axial direction via a ring-shaped thrust pad 25 interposed therebetween. The thrust pad 25 is made of zirconia or alumina ceramic.

  The sewage pump 1A having the above configuration is entirely accommodated in a container (not shown), and the operation thereof will be described below.

  The sewage from the toilet flows into the sewage pump 1A in the container along the inclination of the connection pipe (not shown). In the sewage pump 1A, the motor (M) is driven, and the rotation of the motor shaft 4 is caused by the magnetic attraction generated between the pair of magnets 16 and 22 constituting the magnet coupling. In addition to being transmitted to the cutter 23 and directly to the impeller 29, the mixer 21 and the cutter 29 rotate in the cutter case 27, and the impeller 29 rotates in the pump chamber 37.

  Thus, the sewage flowing into the sewage pump 1A flows into the cutter case 27 from the inlet 27a opened in the side wall of the cutter case 27, and stool such as stool contained therein is finely divided by the rotating cutter 23. After being pulverized, it flows out into the container (not shown) from the plurality of outlets 27b together with the sewage. The sewage containing the spilled sewage (sewage mixed water) is sucked into the pump chamber 37 from the suction port 36 by the pumping action of the impeller 29 rotating in the pump chamber 37, and after being pressurized by the impeller 29, the discharge nozzle 3 a Is discharged to the discharge port 38 and is pumped to a sewer and a septic tank (not shown) through a drain pipe (not shown) connected to the discharge nozzle 3a.

  By the way, if the handkerchief or the like is accidentally dropped into the toilet bowl, the handkerchief or the like cannot be cut by the cutter 23, so that the handkerchief or the like is entangled with the cutter 23 or the mixer 21, and the rotation of the cutter 23 and the mixer 21 is locked. Is done. Even in such a case, since the magnetic coupling is used for the power transmission means from the motor shaft 4 to the cutter 23 and the mixer 21, the motor shaft 4 continues to rotate and is directly connected to the motor shaft 4. The impeller 29 also continues to rotate and performs the required pump function. For this reason, even when the crushing function by the cutter 23 is stopped, at least the impeller 29 normally rotates and continues to pump the sewage, so that the situation that the pumping is impossible is avoided and the sewage overflows from the container. There is no problem.

  If the rotation of the cutter 23 and the mixer 21 cannot be synchronized with the rotation of the motor shaft 4 due to the entanglement of a handkerchief or the like, and a so-called step-out phenomenon occurs, the repulsion between the same poles due to the N pole and the S pole occurs between the magnets 16 and 22. And the inversion of the opposite poles are alternately repeated, and the transmission torque to the cutter 23 becomes almost zero on average. Further, when a step-out phenomenon occurs in the pair of magnets 16 and 22 constituting the magnet coupling, a large vibration is generated by the repulsion and the attracting by the N pole and the S pole, and the vibration is incorporated in the motor case 2. Since it is detected by an acceleration sensor (not shown), for example, an alarm can be issued to notify the occurrence of the step-out phenomenon, and an appropriate treatment can be promoted.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is a cross-sectional view of the cutter part and the impeller part of the sewage pump according to the present embodiment. In this figure, the same elements as those shown in FIGS. 3 and 4 are denoted by the same reference numerals. Hereinafter, description thereof will be omitted.

  The sewage pump 1B according to the present embodiment is basically the same as the sewage pump 1A according to the second embodiment, and a pair of magnets constituting a magnet coupling as power transmission means to the cutter 23. Only the arrangement of 16 and 22 is different.

  That is, of the pair of ring-shaped magnets 16 and 22 constituting the magnet coupling, the small-diameter magnet 16 positioned on the inner side is attached to the outer peripheral portion of the sleeve 41, and the large-diameter magnet 22 positioned on the outer side is the mixer 21. The two are disposed in the radial direction with a predetermined gap δ formed therebetween.

  Thus, the operation of the sewage pump 1B according to the present embodiment is the same as that of the sewage pump 1A according to the second embodiment, and the rotation of the motor shaft 4 is a pair of magnets 16 arranged in the radial direction. , 22 is transmitted to the cutter 23 and the mixer 21 through the magnet coupling constituted by the motor 22 and directly to the impeller 29, so that they are rotationally driven at a predetermined speed. Then, the sewage containing sewage finely crushed by the cutter 23 (sewage mixed water) is sucked into the pump chamber 37 by the pumping action of the impeller 29 rotating in the pump chamber 37, and after being pressurized by the impeller 29, the pump chamber It is discharged outside 37 and is pumped to a sewer or septic tank (not shown) through a drain pipe (not shown).

  By the way, even when a handkerchief or the like accidentally dropped on the toilet bowl gets entangled with the cutter 23 or the mixer 21 and the rotation of the cutter 23 and the mixer 21 is locked, the motor shaft 4 moves to the cutter 23 and the mixer 21. Since a magnetic coupling is used for the power transmission means, the motor shaft 4 continues to rotate, and the impeller 29 directly connected to the motor shaft 4 also continues to rotate to perform a required pump function. For this reason, even when the crushing function by the cutter 23 is stopped, at least the impeller 29 normally rotates and continues to pump the sewage, so that the situation that the pumping is impossible is avoided and the sewage overflows from the container. There is no problem.

  The sewage pressure pump according to the present invention can be used not only as a submersible motor type pump for pumping sewage discharged from a flush toilet or the like, but also for use as a land pump by connecting an appropriate suction pipe. .

It is sectional drawing of the sewage pressure pump which concerns on Embodiment 1 of this invention. It is sectional drawing of the sewage pressure pump which concerns on Embodiment 2 of this invention. It is sectional drawing of the sewage pressure pump which concerns on Embodiment 3 of this invention. It is an expanded sectional view of the cutter part and pump part of a sewage pump according to Embodiment 3 of the present invention. It is sectional drawing of the cutter part and pump part of the sewage pressure pump which concerns on Embodiment 4 of this invention. It is sectional drawing of the conventional sewage pump.

Explanation of symbols

1,1A , 1B sewage pump 2 Motor case 3 Pump case 4 Motor shaft 9, 9 'Rotation sensor 10 Acceleration sensor (vibration sensor)
16 Magnet 21 Mixer 22 Magnet 23 Cutter 25 Thrust pad 27 Cutter case 29 Impeller 37 Pump chamber C Crushing part M Motor P Pump part

Claims (4)

In a sewage pump that rotates and drives a cutter and an impeller by a motor and pumps sewage containing foreign matter crushed by the cutter by the impeller,
The first magnet coupling fixed to one shaft end of the motor shaft and the second magnet fixed to the cutter side are opposed to each other in the motor shaft direction through a partition wall or a thrust pad to constitute a first magnet coupling. The second magnet cup is configured such that the third magnet fixed to the other shaft end of the motor shaft and the fourth magnet fixed to the impeller are opposed to each other in the motor shaft direction through a partition wall or a thrust pad. together constitute a ring, for transmitting each rotation of the motor shaft to the first magnet coupling and the impeller and the second of said cutter via a magnet coupling, the driving torque from the motor to the cutter is set smaller than the driving torque to the impeller, it detects the step-out of the pre-Symbol first magnet cup-ring vibration Dirty water pressure-feed pump, characterized in that incorporating capacitors inside the motor. The drive torque from the motor to the cutter is set smaller than the drive torque to the impeller by making the magnetic flux density of the second magnet smaller than the magnetic flux density of the fourth magnet. The sewage pump according to claim 1. The second magnet and the fourth magnet having the same magnetic flux density are respectively molded, and the mold depth of the second magnet is made deeper than the mold depth of the fourth magnet. 2. The sewage pump according to claim 1 , wherein a driving torque to the impeller is set smaller than a driving torque to the impeller . The distance between the first magnet and the second magnet constituting the first magnet coupling is the distance between the third magnet and the fourth magnet constituting the second magnet coupling. by more, dirty water pressure-feed pump according to claim 1, wherein the driving torque to the cutter was set smaller than the driving torque to the impeller from the motor.

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