JP3170128U - 6-leaf type biaxial volumetric rotary pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 6-leaf 2-axis positive displacement rotary pump capable of suppressing the occurrence of cavitation by providing an air suction port at an optimum position on a suction side of a pump casing. SOLUTION: A rotor casing 7 provided with a suction port portion 8 and a discharge port portion 9 is arranged in a pump casing 4, and a rotor shaft 26 of a pair of rotors 25 housed in the rotor casing 7 is connected to the pump casing 4. A twin-screw volumetric rotary pump p is constructed by freely rotating and supporting the casings fixed to both sides of the pump. Further, the rotor 25 is formed with six blades 27 extending in the radial direction at equal angular intervals about the rotor shaft 26, and the thickness of each blade 27 in the rotation direction is formed to be constant and the top of the blade 27 is formed. The distance from the valley is set to 3 to 5 times the thickness, and the air suction port 16 is provided on the suction side of the casing 4. [Selection diagram] Fig. 2

Description

  The present invention relates to a 6-leaf type biaxial volumetric rotary pump that can be used in a purification device that improves the quality of contaminated water in closed water areas such as rivers and lakes.

  The self-priming pump includes an impeller in a casing having a suction port and a discharge port, and rotates the impeller in a state where a predetermined amount of liquid and gas is sucked into the casing, whereby the liquid and the gas are The pumping operation is performed while stirring. In this self-priming pump, since an unpleasant sound due to cavitation may occur, it is an object to suppress the generation of the unpleasant sound.

  In Patent Document 1, in a sewage roots pump using a three-leaf root rotor, a small-diameter communication port is drilled in the concave arc portion between convex arc portions arranged at intervals of 120 ° of the root rotor toward the axis. A structure for preventing or alleviating the cavitation and the confinement phenomenon in which water is trapped between the concave arc portion and the convex arc portion of the rotor is disclosed by connecting the communication ports.

  In Patent Document 2, in the self-priming pump, the tip of the blade and the casing of the casing inner surface facing the side surface of the blade of the impeller are arranged with the shaft center of the impeller eccentric with respect to the center of the casing. When a groove is provided near the part where the inner surface is closest and at the base of the blade, or a groove is provided in the circumferential direction on the side of the blade, and the pump is continuously operated with the casing filled with liquid, A structure for suppressing a local pressure drop generated at the root portion and suppressing the occurrence of cavitation is disclosed.

Japanese Patent No. 2864357 JP 2008-163819 A

  An object of the present invention is to provide a six-leaf type biaxial volumetric rotary pump that can suppress the occurrence of cavitation by providing an air suction port at an optimum position on the suction side of the pump casing.

In order to achieve the above-mentioned object, the invention according to claim 1 is arranged such that a rotor casing provided with a suction port portion and a discharge port portion is disposed in a pump casing, and a rotor of a pair of rotors housed in the rotor casing. A biaxial volumetric rotary pump in which a shaft is rotatably supported by housings fixed to both sides of the pump casing,
The rotor is formed with six blades extending radially at equiangular intervals around the rotor axis, and the rotor has a uniform thickness in the rotational direction, and the top and valley portions of the blades The interval dimension is 3 to 5 times the thickness, and an air suction port is provided on the suction side of the casing.

  In order to achieve the object, the invention described in claim 2 is the six-leaf biaxial volumetric rotary pump according to claim 1, wherein the air suction port is positioned in front of the suction port portion. It is provided in the pump casing.

  Since the air suction port is provided in the pump casing located in front of the suction port portion of the rotor casing, the liquid and air can be sucked simultaneously, and the occurrence of cavitation can be suppressed.

  Since this 6-leaf type biaxial volumetric rotary pump has a large capacity per rotation of the rotor, a large flow rate can be obtained and low speed rotation can be achieved, so noise and vibration are small. In addition, since the air suction port is provided on the suction side of the pump casing, simultaneous suction of liquid and air becomes possible, and the occurrence of cavitation can be suppressed. Furthermore, it has an excellent performance that a suction air amount of 50% or more with respect to the suction water amount can be obtained and the self-priming performance does not deteriorate.

Front view of 6-leaf type biaxial volumetric rotary pump according to the present invention Same side view Schematic diagram of the main parts of the pump Illustration of shaft seal Explanatory drawing continuously expressed by changing the rotation angle of the rotor Explanatory drawing when the pump according to the present invention is used in a sewage purification apparatus such as a river Explanatory drawing of the pump according to the present invention used in Experiment 1

  The best mode of the present invention will be described below with reference to the drawings.

  As shown in FIG. 2, the six-leaf type biaxial volumetric rotary pump (hereinafter also referred to as the pump according to the present invention) p according to the present invention is opposed to the suction port 8 on the right and the discharge port 9 on the left. A rotor casing 7 provided in a shape is arranged vertically inside the pump casing 4. A peripheral wall portion 7 a above the suction port portion 8 of the rotor casing 7 and the top portion 4 a on the suction port 5 side of the pump casing 4 are connected by a wall 10. Further, the central lower portion 7 b of the rotor casing 7 and the bottom portion 4 b of the pump casing 4 are connected by a vertical wall 11. Reference numeral 12 denotes a bypass hole provided in the vertical wall 11.

  14 and 14 are drain holes provided in the peripheral wall of the pump casing 4, and 15 is a water supply hole provided in the top portion 4 a of the pump casing 4. Reference numeral 18 denotes a cap screwed into the drain hole 14, and 19 denotes a cap screwed into the water supply hole 15.

  Reference numeral 16 denotes an air suction port provided in the pump casing 4 so as to be positioned in front of the suction port portion 8 of the rotor casing 7.

  A flange fitting 21 for piping is attached to the suction port 5 with a check valve 20 interposed therebetween. Similarly, a flange fitting 22 is attached to the discharge port 6.

  As shown in FIG. 2, the rotor casing 7 accommodates a pair of six-leaf rotors 25 and 25. The rotor shaft 26 of the rotor 25 is provided so as to be freely supported by bearings 32 and 32 attached to housings 30 and 31 fixed to both sides of the pump casing 4, respectively. A pulley (not shown) is attached to one end of the lower rotor shaft 26 that protrudes from the housing 30, and the pulley is provided to be driven to rotate by a drive motor 55 via a transmission belt 57. A timing gear 33 is fixed to the other end of the rotor shaft 26, and the timing gears 33 and 33 are engaged with each other. Reference numeral 34 denotes a gear cover attached to the opening of the housing 31.

  As shown in FIG. 3, the rotor 25 is integrally formed with six blades (leaf pieces) 27 extending in the radial direction at equal angular intervals (60 degrees) around the rotor shaft 26. The thickness (t) is formed to be constant and linear when viewed from the side, and the distance (h) between the top 27a and the trough 27b of the blade 27 is provided 3 to 5 times the thickness (t). It is done. And the rotor 25 is provided so that it may rotate in the mutually opposite direction, keeping the clearance gap between the top part 27a of the blade | wing 27 and the inner surface 7c of the rotor casing 7 at about 0.3 mm.

  The gap between the top 27a of the blade 27 of one rotor 25 and the valley 27b of the other rotor 25 is about 1 mm at the maximum. In FIG. 5, at the positions of the rotors 25, 25 shown in (2), (3) and (5), (6), the clearance phenomenon is less likely to occur by providing the gaps. Further, since the volume of the chamber generated when the inner surface 7c of the rotor casing 7 is closed by the top portions 27a of the two blades 27, the capacity per rotation of the rotor 25 is increased, so that a small size and a large flow rate can be obtained. it can.

(Shaft seal)
As shown in FIG. 4, a urethane shock rubber 37 and a seal ring 38 are sequentially attached to the rotor shaft 26 so as to be in close contact with the side end surface of the six-leaf rotor 25. A metal seal ring 38 a is provided on the outer end surface of the seal ring 38. A collar 39 with an oil seal 40 is fitted inside the outer ring 32 a of the bearing 32, and a floating seat 41 is fitted behind the collar 39. 41 a is a metal seal ring provided on the end face of the floating sheet 41. Reference numeral 42 denotes an O-ring that is attached to the reduced diameter portion 41 b of the floating sheet 41 and is in close contact with the inner end surface of the collar 39. Reference numeral 43 denotes a coil spring interposed between a stepped portion 37 a formed inside the shock rubber 37 and the inner end face of the seal ring 38. 44 is a retaining ring mounted on the inner groove 30b of the housing 30 outside the bearing 32, and 45 is a dust seal mounted on the housing hole 30a outside the retaining ring 44.

  Thus, a mechanical seal is formed that seals the shaft by bringing the metal seal ring 38a of the seal ring 38 and the metal seal ring 41a of the floating sheet 41 into contact with each other by the elasticity of the coil spring 43. The other housing 31 is also sealed with a similar mechanical seal.

FIG. 5 shows a state in which the rotation angle of the rotor 25 of the pump (p) according to the present invention is changed continuously every 10 degrees.
Since at most four blades 27 are closed simultaneously with respect to the inner surface 7c of the rotor casing 7 between the suction side and the discharge side, three chambers are formed, so that there is little internal leakage of fluid between the chambers.

  As described above, the fluid sucked from the suction port 5 by the rotating action of the rotors 25 and 25 and the air sucked from the air suction port 16 provided on the suction side of the pump casing 4 are compressed, and the gas-liquid mixed gas is discharged from the discharge port 6. A 6-leaf type biaxial volumetric rotary pump (p) according to the present invention is configured.

(Example of use of the pump according to the present invention)
A usage example of the six-leaf type biaxial volumetric rotary pump (p) according to the present invention will be described with reference to the drawings.
The sewage purification apparatus A shown in FIG. 6 mixes air with the water sucked by the pump (p) of the present invention and blows fine bubbles into the water in a contaminated place such as a river or a lake. Used to improve water quality.

  Specifically, on the machine base 51 provided in the small ship (b) floating in the closed water area, the six-leaf type biaxial volumetric rotary pump (p) of the present invention that constitutes the sewage purification apparatus A, and this are driven. A drive motor 55 is installed. A suction pipe 60 with a strainer 61 attached to the tip is connected to the suction side flange fitting 21 of the pump (p), and a discharge pipe 65 is connected to the discharge side flange fitting 22. 62 is an opening / closing valve interposed in the suction pipe 60, and 66 is an opening / closing valve interposed in the discharge pipe 65. In addition, an air introduction pipe 63 for introducing outside air is connected to the air suction port 16 provided in the pump casing 4 of the pump (p). Reference numeral 64 is an on-off valve interposed in the air introduction pipe 63.

  The pump (p) according to the present invention suppresses the generation of cavitation noise even if a local vacuum is generated by suction negative pressure on the back side in the rotational direction of each blade 27 by simultaneously sucking water and air. The bubbles trapped in the room instantaneously by the pressure on the side are refined. Therefore, in the sewage purification apparatus A, the applicant of the present application has confirmed through experiments that the air released from the pump (p) and dissolved in water becomes fine bubbles and does not diffuse over a long period of time.

(Experiment 1)
As for the six-leaf type biaxial volumetric rotary pump (p) of the present invention, as shown in FIG. 7, air suction ports were provided at various locations on the casing to investigate the effect of suppressing cavitation.
(conditions)
Pump diameter according to the present invention: 150 mm
Rotation speed: 725-560 rpm
Motor output: 5.5kW
Discharged water amount: 1200 to 450 l / min
Intake air volume: 100-200 l / min

  As a result of the experiment, when air is introduced from the position (a) shown in FIG. 7, that is, the position of the pump casing 4 facing the front of the suction port portion 8 of the rotor casing 7, cavitation noise is generated. It was confirmed that it was the least.

p: 6-leaf type biaxial volumetric rotary pump 4 of the present invention 4 ... pump casing 7 ... rotor casing 8 ... suction port 9 ... discharge port 16 ... air suction port 25 .... Rotor 26 ... Rotor shaft 27 ... Blade 27a ... Top part 27b ... Valley part 30, 31 ... Housing

Claims (2)

A rotor casing provided with a suction port and a discharge port is arranged in the pump casing, and the rotor shafts of a pair of rotors housed in the rotor casing are rotated by housings fixed to both sides of the pump casing. A freely supported biaxial volumetric rotary pump,
The rotor is formed with six blades extending radially at equiangular intervals around the rotor axis, and the rotor has a uniform thickness in the rotational direction, and the top and valley portions of the blades A six-leaf type biaxial volumetric rotary pump characterized in that the interval dimension is 3 to 5 times the thickness, and an air suction port is provided on the suction side of the casing.   The six-leaf type biaxial volumetric rotary pump according to claim 1, wherein the air suction port is provided in the pump casing so as to be positioned in front of the suction port portion.

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