JPH0713520B2 - Fluid pump - Google Patents

Description

The present invention relates to a fluid pump used for transporting a fluid such as a liquid.

[Prior Art] Conventionally, as one example of a fluid pump, for example, a pump having a structure shown in FIG. 4 is known.

The pumping pump 1 comprises a casing 2, an impeller 3 rotatably mounted on the casing 2, and a diffuser 4 for discharging fluid, which is provided on a peripheral wall of the casing 2 along a tangential direction thereof. The inner peripheral surface of the casing 2 is formed into a substantially perfect circular shape so as to form a predetermined space over the entire circumference between the inner peripheral surface of the casing 2 and the outermost rotation locus of the impeller 3, that is, a so-called circular shape. It is made with a casing.

The pumping pump 1 having such a configuration is the impeller 3
By rotating the, the centrifugal force is applied to the water in the casing 2 to pump the water from the center of the casing 2 to the peripheral wall, and the water is discharged from the diffuser 4 formed on the peripheral wall to the outside. It has become.

[Problems to be Solved by the Invention] In the pumping pump 1, however, the following demands have been made in order to prevent a decrease in pump efficiency.

That is, the water to be sent out has a proportion of pressure energy indicated by the reaction degree at the exit of the impeller 3 and residual kinetic energy, and the discharge port, that is, the discharge of the diffuser 4 without reducing the pressure energy as much as possible. Of the kinetic energy other than the kinetic energy corresponding to the average velocity head at the discharge port, and converting it into pressure energy as much as possible.

If this is described in detail with reference to the pressure-flow rate diagram shown in FIG. 5, the pressure P ₀ (static pressure) at the outlet of the impeller 3 is kept substantially constant without being affected by the flow rate.

On the other hand, the theoretically calculated inflow pressure (static pressure) P ₁ ′ near the inlet of the diffuser 4 and discharge pressure (also static pressure) P ₂ tend to decrease with an increase in the flow rate.

However, in the conventional pumping pump 1, as shown by the pressure P ₁ in FIG. 5, the pressure P ₁ ′ drops even earlier than the theoretical pressure P ₁ ′ at a large rate of change.

The following are possible causes of such a phenomenon.

That is, the fluid flowing into the diffuser 4 has a streamline in the tangential direction of the casing 2 as a whole, but the remaining fluid further tries to flow along the inner peripheral surface of the casing 2, so that the casing of the diffuser 4 is made to flow. This is because the streamline changes at the corner A of the inner portion of 2 to cause cavitation, and as a result, the substantial flow passage area of the inflow portion of the diffuser 4 is narrowed and the flow velocity increases. It is considered to be a thing.

Therefore, conventionally, it has been desired to deal with these problems, and the present invention is to solve the problems that remain in the related art.

[Means for Solving the Problems] The present invention is to provide a fluid pump capable of effectively solving the above-mentioned problems. By rotating an impeller arranged in the casing, the inside of the casing is improved. Is a fluid pump configured to apply a centrifugal force to the fluid to discharge the fluid from a discharge port formed in a peripheral wall of the casing, wherein the casing has a rotation locus of an outermost periphery of the impeller. A pump chamber having a substantially perfect circular inner peripheral surface formed at a predetermined interval is formed, and the discharge port has:
A diffuser is provided which projects between the impeller and the inner peripheral surface of the casing and guides the fluid flowing between them to the outside of the casing. The diffuser is substantially tangential to the inner peripheral surface of the casing. It is characterized in that it is provided with an introduction port opened orthogonally and a fluid stabilizing passage which is continuous with the introduction port and which is curved so as to follow the rotation radius direction of the impeller.

[Operation] In the fluid pump according to the present invention, the fluid inlet in the diffuser is opened substantially orthogonal to the tangential direction of the inner peripheral surface of the casing, so that the fluid in the casing flows in the streamline direction and flows into the diffuser. The streamline direction at the time is made to substantially coincide with each other to prevent the occurrence of cavitation at the diffuser introduction port portion, and suppress the decrease in pressure energy at this introduction port portion.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, reference numeral 10 denotes a fluid pump according to the present embodiment, and by rotating an impeller 12 arranged in a casing 11, a centrifugal force is applied to the fluid in the casing 11, A fluid pump configured to discharge fluid from a discharge port 13 formed on a peripheral wall of the casing 11, wherein the casing 11 has a predetermined interval from a rotation locus of the outermost periphery of the impeller 12. The pump chamber 14 having the formed substantially circular inner peripheral surface 14a is formed, and the discharge port 13
Is provided with a diffuser 15 which projects between the impeller 12 and the inner peripheral surface 14a of the casing 11 and guides a fluid flowing between the impeller 12 and the outside of the casing 11. The diffuser 15 includes the diffuser 15. Introducing port 15a opened substantially orthogonal to the tangential direction of the inner peripheral surface 14a, and this introducing port 15a
And a fluid guide passage 15b which is curved so as to extend along the radial direction of rotation of the impeller 12.

Next, these details will be described.

As shown in FIG. 2, the casing 11 has a first casing 17 in which a drive shaft 16 is rotatably inserted in a central portion, and a disk-shaped pump chamber 14 attached to the first casing 17. The second casing 18 is formed, and an annular bush 19 is formed in a through hole 17a of the first casing 17 into which the drive shaft 16 is inserted while the movement toward the pump chamber 14 is restricted. A plurality of gland packings 20 are mounted on the outer side of the bush 19, and a packing retainer 21 that holds the gland packings 20 with the bush 19 is mounted.

This packing presser 21 is
It is pressed toward the bush 19.

Further, the second casing 18 is detachably fixed to the first casing 17 by a plurality of bolts 24 and nuts 25.

In the present embodiment, the impeller 12 has six blade portions 26.
As shown in FIG. 2, they are provided along the radial direction of the drive shaft 16 and at regular intervals in the rotation direction of the drive shaft 16.

Further, these vane portions 26 are formed in a substantially quadrangular outer shape, and, as shown in FIG. 1, both side surfaces in the rotational direction are tapered so that they gradually expand as they go to the base portion 27. Has been formed.

Further, the fluid passage 26a formed in each blade portion 26 has a square cross section, and is formed in a constant shape from the central portion side to the outer peripheral portion side of the impeller 12.

A collar 28 is fitted on the outer peripheral portion of the drive shaft 16, and the collar 28 is arranged so as to penetrate the packing retainer 21, the gland packing 20, and the bush 19 to thereby provide the collar 28. It is rotatably and liquid-tightly inserted into the first casing 17 via the.

Further, the drive shaft is provided at the center of the second casing 18.
16 and a fluid suction port 18a coaxial with 16 and a fluid suction port 18a of the second casing 18 at the center of rotation of the impeller 12.
An inlet port 26b communicating with each of the fluid passages 26a is formed in a portion facing each other.

On the other hand, the diffuser 15 is provided with a guide portion 15c radially penetrating the peripheral wall of the second casing 18 and a guide portion 15c which is continuous with the guide portion 15c and extends along the inner peripheral surface 14a of the casing 11. And a rectifying unit 15d formed as described above.

The inlet 15a is formed at the end of the rectifying portion 15d on the upstream side in the fluid flow direction.

Further, as shown in FIG. 3, the rectifying portion 15d is formed in a streamline shape so that the width dimension thereof gradually narrows as it goes to the downstream side in the fluid flow direction as viewed from the radial direction of the casing 18. ing.

Further, in the diffuser 15, a screw portion 29 is formed on the outer periphery of the guide portion 15c, and in the vicinity of the screw portion 29, a flange portion 30 that is engaged with the casing 11 from the inside thereof is formed. The nut 31 and the collar portion 30 screwed to the screw portion 29 are fixed to the peripheral wall of the casing 11.

Therefore, the fluid pump of the present embodiment configured as described above
An electric motor or the like rotates the drive shaft 16 to rotate the impeller 12, thereby rotating the fluid in the casing 11 to give a centrifugal force to the inner peripheral surface 14a of the casing 11.
The fluid is continuously sucked and sent out by sucking the fluid into the casing 11 from the suction port 18a while rotating it along the flow direction and sending it to the outside through the diffuser 15 interposed in the flow direction.

That is, with the rotation of the impeller 12, a centrifugal force is applied to the fluid in each fluid passage 26a of the impeller 12, the fluid is pushed out from the base portion 27 to the tip side of each vane portion 26, and the pump chamber 14 The fluid filled in the inner peripheral surface of the pump chamber 14 is rotated by the front side surface of each vane portion 26 in the rotational direction, and is given a centrifugal force like the fluid in the fluid passage 26a.
It is pressed toward 14a, rotated in the rotating direction of the impeller 12, and pushed out of the casing 11 from the diffuser 15.

Then, the fluid in the fluid passage 15 and the pump chamber 14 is pushed to the outside, and the pressure in the vicinity of the base portion 27 is reduced, so that the suction port 18a and the introduction port 26b are provided in the vicinity of the base portion 27.
The fluid is drawn into the casing 11 via.

By continuously performing this operation, the fluid is continuously discharged from the casing 11.

During such a fluid discharge operation, since the inlet 15a of the diffuser 15 is provided substantially orthogonal to the streamline of the fluid, the disturbance of the streamline in the vicinity of the inlet 15a is suppressed.

Therefore, the generation of vortices at the inlet 15a is suppressed, the change in the flow velocity near the inlet of the diffuser 15 is suppressed, and the pressure energy of the fluid is prevented from decreasing, and as a result, the pump efficiency is improved.

On the other hand, the remaining fluid that cannot flow into the diffuser 15 flows rearward along the outer peripheral surface of the diffuser 15.

Here, since the diffuser 15 is formed in a streamlined shape so as to gradually taper rearward in the fluid flow direction, separation of the fluid on the outer peripheral surface of the diffuser 15 is suppressed, and the diffuser 15 is smoothly guided rearward. .

Also from this point, the influence on the fluid sent to the diffuser 15 is mitigated, and the pump efficiency is improved as a whole.

It should be noted that the shapes, sizes, and the like of the respective constituent members shown in the above embodiment are examples, and can be variously changed based on design requirements and the like.

[Effects of the Invention] As described above, in the fluid pump according to the present invention, by rotating the impeller arranged in the casing, a centrifugal force is applied to the fluid in the casing, and the fluid is treated as described above. A fluid pump configured to discharge from a discharge port formed on a peripheral wall of a casing, wherein the casing has a substantially circular shape formed at a predetermined interval from a rotation locus of an outermost periphery of the impeller. A pump chamber having an inner peripheral surface of is formed, and the discharge port is provided with a diffuser that projects between the impeller and the inner peripheral surface of the casing and guides a fluid flowing between the impeller and the outside of the casing. This diffuser has an inlet opening which is opened substantially orthogonal to the tangential direction of the inner peripheral surface of the casing, and a bay which is continuous with the inlet and extends along the radial direction of rotation of the impeller. It is characterized by having a curved fluid guide passage, and has the following excellent effects.

During the fluid discharge operation, the diffuser inlet, which is the outlet path for the fluid, is provided approximately orthogonal to the fluid streamline, thus suppressing the disturbance of the fluid streamline near this inlet. can do.

Therefore, it is possible to suppress the generation of vortices at the inlet, suppress the increase in the flow velocity near the entrance of the diffuser, and suppress the decrease in the pressure energy of the fluid. As a result, it is possible to improve the pump efficiency.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention,
1 is a vertical cross-sectional front view of a main part, FIG. 2 is a vertical cross-sectional side view of an impeller, FIG. 3 is an arrow view taken along the line III-III of FIG. 1, FIG. 4 and FIG. FIG. 4 shows an example of a conventional fluid pump, FIG. 4 is a schematic diagram of a main part, and FIG. 5 is a pressure-flow rate diagram for explaining pressure energy at each point of the fluid pump. 10 ... Fluid pump, 11 ... Casing, 12 ... Impeller, 13 ... Discharge port, 14 ... Pump chamber, 14a ... Inner surface, 15 ... Diffuser, 15a ... Inlet port, 26 ... Blade part, 15c ... Guide part, 15d ... rectifying part.

Claims (1)

[Claims] 1. A centrifugal force is applied to a fluid in the casing by rotating an impeller arranged in the casing, and the fluid is discharged from a discharge port formed in a peripheral wall of the casing. In the fluid pump, the pump chamber is formed in the casing, the pump chamber having a substantially perfect circular inner peripheral surface formed at a predetermined interval from the outermost rotation locus of the impeller. The outlet is provided with a diffuser that projects between the impeller and the inner peripheral surface of the casing and guides the fluid flowing between the two to the outside of the casing. An inlet opened substantially orthogonal to the direction,
A fluid pump provided with a fluid guide passage which is continuous with the introduction port and which is curved so as to extend along a rotation radius direction of the impeller.