JP3191362U - Self-priming pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-priming pump suitable for a sanitary plant with less noise, vibration and energy consumption. SOLUTION: A self-priming pump is housed in a spiral casing having a vortex chamber formed therein, a sub-casing 16 arranged on the suction side of the vortex chamber, an impeller housed inside the vortex chamber, and a sub-casing 16. The sub-casing 16 is provided with the screw wheel 22 and has an elliptical or oval shape having centers O1 and O2 at positions facing each other in the radial direction. [Selection diagram] Fig. 2

Description

  The present invention relates to a self-priming pump having a structure in which a pumping impeller (impeller) can also perform priming, and more specifically, but not limited to, is used in food plants, pharmaceutical plants, etc. Relates to a self-priming sanitary pump.

  2. Description of the Related Art Conventionally, a self-priming pump used in a food plant includes a casing whose volume is changed or eccentric, and an impeller having a plurality of blades radially. When the impeller rotates, liquid (priming water) enclosed in the casing is the casing. Rotating along the inner wall, a crescent-shaped cavity is formed in the center of the impeller. The gas in the cavity is divided and divided by radial vanes. One divided volume causes expansion / compression volume change every rotation. Therefore, if an opening is provided on the start side of expansion and the final part of compression, the cycle of suction / expansion / compression / discharge is performed by rotational movement, and self-priming action and pump action are exhibited (see Non-Patent Document 1).

Hiroshi Inoue, Sanitary Self-Priming Pump, Piping and Equipment, VOL. 32, NO. 5, May 1, 1992, Sanko Planning Co., Ltd., pp. 39-42

  The conventional self-priming pump structure has the following problems.

  Since the compressed gas expands rapidly, noise is generated, and when the impeller rotates at high speed, the explosion sound is continuously high. In food plants with many indoor installations, high noise during operation adversely affects the surrounding work environment.

  Since the centrifugal force applied from the rotating impeller is not converted into energy for pumping the pumped liquid, the pump efficiency is low. Therefore, energy consumption is high and uneconomical.

  Since the radial load on the impeller and the main shaft due to the water pressure of the sealing water swirling in the casing is not uniform in the circumferential direction, the unbalanced radial load causes vibration and shortens the mechanical life.

  An object of the present invention is to provide a self-priming pump suitable for a sanitary plant that eliminates the above-described problems and consumes less noise, vibration, and energy.

The self-priming pump of the present invention includes a spiral casing having a vortex chamber formed therein, a subcasing disposed on the suction side of the vortex chamber, an impeller accommodated in the vortex chamber, and accommodated in the subcasing. The sub-casing has an elliptical or oval shape having a center at a position opposed to the diameter direction.

  Since the hollow part formed inside the sealing ring is formed in two places opposed in the diameter direction, the intake air amount is doubled and the self-priming property is increased. Also, the radial load on the spindle due to the hydraulic pressure is balanced, eliminating the cause of vibration. Furthermore, the number of turns of the screw is halved, and a small and light weight is realized.

  According to this device, noise during operation is not high and the working environment is improved. Moreover, since there is no significant decrease in pump efficiency, energy can be saved. In addition, there is little vibration and long life can be expected.

It is a longitudinal cross-sectional view of the self-priming pump for demonstrating embodiment of invention. It is a cross-sectional view of the self-priming pump of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  The self-priming pump shown in FIG. 1 is a kind of centrifugal pump, and includes a spiral casing 10, a subcasing 16, an impeller 20, and a screw wheel 22 as main components.

  The spiral casing 10 forms a vortex chamber 10a for accommodating the impeller 20 therein. The vortex chamber 10a is literally spiral, and as the impeller 20 rotates, the axial center portion becomes low pressure and the outer peripheral portion becomes high pressure. Corresponding to the pressure distribution in the vortex chamber 10a, the vortex casing 10 includes a suction port 10b coaxial with the impeller 20 and a radial discharge port 10c communicating with the high pressure portion. The liquid is sucked from the suction port 10b and discharged from the discharge port 10c.

  The spiral casing 10 includes a casing body 12 and a casing cover 14, and is coupled to an electric motor and other driving devices M via a bracket 30. The casing cover 14 has a stuffing box 14a, and a mechanical seal 28 for sealing the shaft between the spiral casing 10 and the main shaft 24 is installed in the stuffing box 14a. The mechanical seal 28 is a sealing device in which a stationary ring attached to the stuffing box 14a side and a rotating ring attached to a boss of the impeller 20 are relatively rotated while being elastically pressed. Since the details of the mechanical seal 28 are well known, a detailed description is omitted here. It is also possible to employ a gland packing instead of the mechanical seal.

  The impeller 20 is attached to a main shaft 24, and the main shaft 24 is rotationally driven by a driving device M. By a conventional method, the impeller 20 and the main shaft 24 are coupled so as to be able to transmit torque. FIG. 1 shows an example of using keys. The impeller 20 is provided with a through hole 20a called a balance hole. This serves to convection the sealing liquid in the stuffing box 14a to improve the cleaning performance and to reduce the thrust load acting on the impeller 20 during operation.

  The screw wheel 22 is located on the upstream side of the impeller 20. The impeller 20 and the screw wheel 22 are positioned and fixed on the main shaft 24 by fitting each boss portion with the main shaft 24 and tightening a cap nut on the male screw at the tip of the main shaft 24. As can be seen from FIG. 2, the screw wheel 22 is formed by forming spiral blades 22b on the outer periphery of a cylindrical boss 22a. The screw wheel 22 is accommodated in the sub casing 16.

The sub casing 16 is detachably attached to the suction port 10 b portion of the spiral casing 10 using a clamp band 26. A cross section of the sub casing 16, that is, a cross section perpendicular to the central axis is elliptical or oval. FIG. 2 exemplifies a shape in which two rows of cylinders, that is, two cylinders (centers are respectively indicated by reference numerals O ₁ and O ₂ ) are arranged side by side, but may be arranged vertically. As far as the subcasing 16 is concerned, FIG. 1 shows a cross section taken along the line II of FIG.

  The blade 22 b of the screw wheel 22 has an outer diameter that forms a minute gap with the inner peripheral surface 16 a of the sub casing 16. The blades 22b have at least one spiral shape and act to feed the gas phase of the pumped liquid from the suction side toward the suction port 10b without backflow. As long as such an effect is obtained, the number of blades 22b or the number of spirals is not particularly limited, but FIG. 1 is an example of three spirals. As the screw wheel 22 rotates, the pressure at the suction port 10 increases, and as a result, the NPSH is lowered, and it also helps prevent cavitation.

  Through holes 10 d and 16 b are provided in the lowermost part of the vortex chamber 10 a of the spiral casing 10 and the lowermost part of the sub casing 16, respectively, and these through holes 10 d and 16 b are connected by a recycle pipe 18. Although illustration is omitted, if necessary, a drain valve may be attached on the extension of the recycle pipe 18, and a control valve may be attached on the pipe line of the recycle pipe 18.

  The lowermost part of the vortex chamber 10a is sufficiently higher in pressure than the upstream side of the screw wheel 22, and there is only a liquid phase separated from the gas phase. Therefore, during the operation of the pump, the high-pressure liquid is returned to the outer periphery of the screw wheel 22 on the upstream side of the screw wheel 22 from the high-pressure side of the spiral casing 10 through the recycle pipe 18.

  The pump according to the embodiment having the above-described configuration is a sanitary pump that is hygienic and generates a self-priming action. Also, the internal structure of the pump shall be a smooth finished surface with no liquid accumulation and good cleanability.

  Before starting the pump, it is necessary to fill the inside of the spiral casing 10 with the liquid, that is, priming.

  When the pump is started, the liquid (primary water) sealed in the sub casing 16 and the spiral casing 10 is activated along the inner wall of the sub casing 16 by centrifugal force accompanying rotation of the screw wheel 22 in the sub casing 16. It turns, and as shown in FIG. 2, the sealing ring A of an ellipse or an ellipse shape is formed.

  Since the sealing ring A has an elliptical or oval shape and the outer peripheral surface of the boss 22a of the screw wheel 22 has a cylindrical shape, a crescent-shaped cavity B faces the diametrical direction therebetween. It is formed at two places in the circumferential direction. The gas in the cavity B is scraped off by the blades 22b of the rotating screw wheel 22, and is pushed into the impeller 20 in a sealed state.

  In the spiral casing 10, the gas pushed by the screw wheel 22 is mixed with priming water and is blown into the vortex chamber 10 a by centrifugal force accompanying the rotation of the impeller 20. While the gas mixture is swirling in the vortex chamber 10a, the gas is pushed out toward the discharge port 10c on the outer diameter side, and the liquid is pumped from the bottom through-hole 10d to the sub casing 16 through the recycle pipe 18, In this way, the gas and liquid are separated.

  The liquid returned to the sub casing 16 through the recycle pipe 18 automatically replenishes the amount of water necessary to maintain the shape of the sealing ring A that generates a self-priming action.

By repeating such a cycle, a self-priming action can be generated.
In the operation in the full liquid state, the pump action of the screw wheel 22 pushes the liquid into the impeller 20, the pump suction performance (anti-cavitation resistance) is good, there is no sudden change in the liquid flow, There is no significant decrease in pump efficiency.

The operation of the self-priming pump of the above-described embodiment is as follows.

When stopped, the pumped liquid accumulates in the lower part of the spiral casing 10 and the upper part of the spiral casing 10 is in a gas phase.

When activated, the pumped liquid becomes annular along the inner wall of the spiral casing 10 by the action of centrifugal force accompanying the rotation of the impeller 20 and circulates in the vortex chamber 10a.

The pumped liquid circulating in the vortex chamber 10a of the vortex casing 10 is pumped into the sub casing 16 through the recycle pipe 18 from the lowermost through hole 10d and returned to the inlet side of the screw wheel 22 at a high speed. At that time, the gas near the suction port 10 b is also sucked and flows into the screw wheel 22.

The gas mixture that has flowed into the screw wheel 22 is separated into a liquid phase by an outer peripheral portion and a gas phase by an action of centrifugal force accompanying rotation of the blade 22 b of the screw wheel 22. Furthermore, since the fuel is injected from the recycle pipe 18 toward the outer periphery of the blade 22b of the screw wheel 22, there is no concern that the gas flows backward from the outer periphery of the blade 22b.

In this way, the gas sealed between the blade 22b and the blade 22b of the screw wheel 22 is liquid-sealed and pumped to the impeller 20 in a conveyer manner without flowing back to the suction side.

The pumped liquid of the gas-liquid mixture is blown by the impeller 20 to the vortex chamber 10 a of the vortex casing 10.
The gas-liquid pumped liquid circulating in the vortex chamber 10a of the vortex casing 10 is discharged from the discharge port 10c at the upper part of the vortex casing 10 and the liquid phase is taken out from the lower through-hole 10d of the vortex chamber 10b. Gas-liquid separation is performed. In this way, only the liquid phase circulates from the recycle pipe 18 to the screw wheel 22.

By repeating the above cycle, a self-priming action for discharging the gas phase on the pump suction side to the discharge side is generated.

The effects of the above-described embodiments can be summarized and listed as follows.

The self-priming pump of the embodiment includes a spiral casing 10 in which a vortex chamber 10a is formed, a subcasing 16 disposed on the suction side of the vortex chamber 10a, an impeller 20 accommodated in the vortex chamber 10a, and a subcasing 16 The sub-casing 16 has an elliptical or oval shape having a center at a position opposed to the diameter direction.

Then, by connecting the lowermost part (10d) of the spiral casing 10 and the lowermost part (16b) of the subcasing 16 with the recycle pipe 18, the high-pressure liquid in the vortex chamber 10a is returned to the upstream side of the screw wheel 22. A self-priming action for discharging the gas phase on the pump suction side to the discharge side is generated.

  Further, at the time of stoppage, since the remaining liquid can be completely recovered by removing the recycle pipe 18, it is excellent in cleaning and sterilization in the machine, and is clean and hygienic. Therefore, it is particularly suitable for a sanitary pump.

  By attaching a drain valve to the recycle pipe 18, it is possible to collect all the remaining liquid in the pump. Therefore, the liquid pool in the pump, which is a factor for the propagation of germs, is not made normal, so it is clean and hygienic. This is also an advantage as a sanitary pump.

  By attaching a control valve to the recycle pipe 18, the amount of water returned to the sub casing 16 is adjusted during the intake operation, and the pump is increased by fully closing the valve to restrict the liquid circulation during the full operation. Can do.

  By attaching the sub casing 16 to the spiral casing 10 in a detachable manner, the pump can be easily disassembled and assembled, which contributes to improving the efficiency of maintenance and cleaning operations.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described and illustrated herein, and various modifications can be made without departing from the scope of the claims. It goes without saying that it can be done.

DESCRIPTION OF SYMBOLS 10 Spiral casing 10a Vortex chamber 10b Suction port 10c Discharge port 10d Through hole 12 Casing main body 14 Casing cover 14a Stuffing box 16 Subcasing 16a Inner peripheral surface 16b Through hole 18 Recycle pipe 20 Impeller 20a Balance hole 22 Screw wheel 22a Boss 22b Blade 24 Main shaft 26 Clamp band 28 Mechanical seal 30 Bracket A Sealing ring B Cavity M Drive units O ₁ and O ₂ center

Claims (5)

A spiral casing having a vortex chamber formed therein;
A sub-casing disposed on the suction side of the vortex chamber;
An impeller housed inside the vortex chamber;
A self-priming pump comprising: a screw wheel housed inside the sub casing; and a cross section of the sub casing having an elliptical or oval shape centered at a position opposed to the diameter direction. The self-priming pump according to claim 1, wherein a lowermost part of the spiral casing and a lowermost part of the sub casing are connected by a recycle pipe.   The self-priming pump according to claim 2, wherein a drain valve is attached to the recycling pipe.   The self-priming pump according to claim 2 or 3, wherein a control valve is attached to the recycle pipe.   The self-priming pump according to any one of claims 1 to 4, wherein the sub casing is detachably attached to the spiral casing.

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