JPH07243398A - Synthetic resin centrifugal pump - Google Patents

Abstract

PURPOSE:To adjust a gap with high accuracy by permitting a dimension A to be measured accurately even when the outer diameter of an impeller is made small. CONSTITUTION:A guide vane 4 is provided in this synthetic resin pump casing. An open-type synthetic resin centrifugal impeller 40 which is rotated by a driving shaft 26 is disposed to face the guide vane 4. Plural vanes 42 which are of spiral shape are provided in front of the back surface plate 41 of the centrifugal impeller. The vane has a tapered part 42a, at which a flat surface 44 located on the back side of a rotational direction and parallel to the back surface plate is formed. The flat surface which is formed on the vane provides a reference surface for measurement, making it possible to measure a dimension A. Since the flat surface is formed on the back side of the rotational direction, a gap between the vane and the guide vane is kept small, thereby preventing water leakage from increasing and pumping characteristics from being affected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-open type centrifugal pump made of synthetic resin in which a pump casing and a centrifugal impeller are made of synthetic resin, and the centrifugal impeller is open at the front side.

[0002]

2. Description of the Related Art In a centrifugal pump for handling seawater or chemical liquids, if the wetted parts such as pump casing and centrifugal impeller are made of metal material such as cast iron or stainless steel, the wetted parts will come into contact with seawater or chemical liquids. There is a problem that causes rust and corrosion. For this reason, there is known a spiral pump in which the pump casing and the centrifugal impeller are made of synthetic resin such as PPE resin.

Among centrifugal pumps of this type, there is a centrifugal impeller having a semi-open structure. That is, an ordinary centrifugal impeller has a back plate (also referred to as a main plate), a front plate facing and spaced from the back plate, and radially arranged between the back plate and the front plate and extending spirally. It is composed of a plurality of blades. When such an impeller is rotated by a drive shaft connected to the central part, liquid is introduced from a suction hole opened in the central part of the front plate, and this liquid is added through a spiral passage between each blade. It is designed to be pressed and delivered from the discharge port opened to the outer peripheral portion.

On the other hand, as shown in FIG. 5, the semi-open type centrifugal impeller 40 has a back plate 41 and a plurality of blades radially arranged on the front face of the back plate 41 and extending spirally. 42, there is no front plate, and the front side is open.

By the way, such an open type centrifugal impeller 4
In the centrifugal pump using 0, the pumping performance depends on the size of the gap G between the front surface of the blade 42 shown in FIG. 2 and the guide vane 4. That is, since there is no front plate in the impeller 40, when the gap G between the front surface of the blade 42 and the guide vane 4 is large, the liquid pressurized in the spiral passage 43 leaks, and the leak amount increases and the pumped water is pumped. The efficiency decreases, and if the gap G is small, the wall resistance increases, so that the rotation efficiency of the impeller 40 decreases. Therefore, the gap G between the front surface of the blade 42 and the guide vane 4 needs to be managed with high accuracy.

As shown in FIG. 2, the gap G has an A dimension from the inner surface of the casing cover 5 to the front surface of the impeller 40 and a B dimension from the inner surface of the casing cover 5 to the back surface of the guide vane 4. Measure the difference B-
Obtained by A = G. The value of BA is the predetermined gap G
When it does not become (normally 0.5 to 1.5 mm), an adjustment shim 49 is interposed between the step portion 26a of the drive shaft 26 and the impeller 40, and the thickness of the adjustment shim 49 is adjusted to set the G dimension. I am trying to adjust it.

In this case, for the dimension A, the dimensions of the wall surface of the casing cover 5 and the front surface of the blade 42 are measured while the centrifugal impeller 40 is passed through the drive shaft 26 and the tightening nut 48 is tightened. For the B dimension, the distance between the wall surface of the casing cover 5 and the guide vane 4 is measured.

[0008]

However, in the semi-open type impeller 40, as shown in FIG. 5, the front shape of the blade 42 is the tapered portion 42a and the rear plate 41 is provided on the outer peripheral portion of the tapered portion 42a. Parallel plane 42
There is a structure which provides b. In such a structure, when measuring the A dimension, the casing cover 5
It suffices to measure the dimensions of the wall surface and the parallel surface 42a. Therefore, such an impeller 40 can easily adjust the gap G.

Generally, in a pump, the pump output changes when the outer diameter D of the centrifugal impeller 40 is changed. Therefore, the outer diameter D of the centrifugal impeller 40 is cut to remove the impeller 40.
The smaller the diameter of, the smaller the pump output. Therefore, for multiple output pumps, multiple centrifugal impellers made of the same type and made of synthetic resin were manufactured in advance, and for pumps with different outputs and different rotational speeds, the outer diameter of the impeller was cut. If the impeller adapted to the pump is manufactured, the mold cost can be reduced and the manufacturing becomes easy.

However, in the conventional impeller 40 as shown in FIG. 5, when the outer diameter is cut and the maximum diameter D1 is applied to the taper portion 42a, there is no measurement reference surface for measuring the A dimension. Accurate measurement of dimensions is impossible. In such a case, the dimension of the gap G cannot be measured, and the pump performance may vary.

The present invention has been made in view of the above circumstances. An object of the present invention is to enable accurate measurement of the A dimension even if the outer diameter of the impeller is made small, and to make the gap G highly accurate. The present invention intends to provide a centrifugal pump made of synthetic resin that can be adjusted.

[0012]

According to a first aspect of the present invention, a guide vane is provided in a pump casing made of synthetic resin, and a centrifugal impeller made of synthetic resin is installed facing the guide vane. A drive shaft for rotating the centrifugal impeller is connected to a central portion of the impeller, and the centrifugal impeller is provided with a large number of spirally extending blades arranged substantially radially on the front surface of the back plate. Has a taper portion whose height decreases toward the outer peripheral direction, and in the centrifugal pump made of synthetic resin which is an open type impeller in which the front side of these blades is open, the taper portion of the blade is A flat surface parallel to the back plate is formed on the back side in the rotation direction.

According to a second aspect of the present invention, in the case of an open type impeller in which a parallel portion parallel to the back plate is formed on an outer peripheral portion of the blade connected to the tapered portion, a flat surface formed on the tapered portion of the blade. Is formed on the same surface as the parallel portion.

[0014]

According to the first aspect of the present invention, since the flat surface parallel to the back plate is formed on the tapered portion of the blade, the A dimension can be measured using this flat surface as the measurement reference surface. Moreover, in this case, since the flat surface is formed on the back side in the rotation direction of the blades and the taper portion is left on the front side, the gap with the guide vanes does not increase, and it is possible to prevent an increase in water leakage and improve pumping characteristics. Has no effect.

According to the second aspect of the present invention, since the flat surface formed on the taper portion and the parallel portion following the taper portion are formed on the same surface, an impeller having a large diameter and having the parallel portion and an outer diameter cut are formed. In any of the impellers with no parallel part,
The same A dimension can be measured.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIGS. In the figure, 1 is PPE
The pump casing is made of synthetic resin such as resin. In this synthetic resin pump casing 1, a suction port 2 is opened in the center of the front surface, and a casing cover 3 is attached to the opening of the back surface. The casing cover 3 is also made of synthetic resin such as PPE resin, and the casing cover 3 of this embodiment has guide vanes 4 inside.
Is integrally formed, and the bracket 5 is integrally formed on the outer side. Such a casing cover 3 is fixed to the pump casing 1 by using mounting bolts 6 ...

A flange pipe joint 7 is attached to the front surface of the pump casing 1 so as to face the suction port 2. The flange pipe joint 7 is fixed to the pump casing 1 by fixing bolts 8 ... And a suction pipe (not shown) is connected to the flange pipe joint 7. A valve seat 9 is formed on an inner end surface of the flange pipe joint 7, and a valve body 10 that constitutes a one-way valve is formed on the valve seat 9.
Is designed so that it can be attached and detached. The valve body 10 is integrally provided with a packing portion 11 on the periphery thereof, and the packing portion 11 is sandwiched between the flange pipe joint 7 and the pump casing 1. The valve body 10 is adapted to come into contact with and separate from the valve seat 9 by elastically deforming a root portion connected to the packing portion 11. When the fluid pressure is applied from the inside of the pump casing 1, the valve body 10 is moved to the valve seat 9. Sit down and close inlet 2.

A partition wall 14 is formed inside the pump casing 1, and an introduction passage 15 that communicates with the suction port 2 is formed inside the partition wall 14. The end of the partition wall 14 is butt-connected to the guide vane 4 via an O-ring 16. Partition wall 1
A gas-liquid separation chamber 17 surrounded by the pump casing 1 is formed on the outer peripheral portion of the nozzle 4. And the pump casing 1
A discharge port 18 is opened on the upper wall of the device, and a suction pipe (not shown) is connected to the discharge port 18.

A priming port 19 is opened on the upper wall of the pump casing 1, and the priming port 19 is closed by a priming port closing plug 20. In addition, a drain port 21 is opened in the lower wall of the pump casing 1,
The drain port 21 is closed by a drain port closing plug 22.

The bracket 5 formed integrally with the casing cover 3 has an electric motor 25 through a connecting bolt 24.
Are linked to. The electric motor 25 includes a drive shaft 26 integral with the electric motor shaft, and the drive shaft 26 is introduced into the pump casing 1 through a drive shaft introduction hole 27 opened at the center of the casing cover 3. A centrifugal impeller 40, which will be described later, is fixed to the tip of the drive shaft 26 via a fixing nut 48.

A fixed leg 28 is formed integrally with the bracket 5, and the fixed leg 28 is attached to a fixed base 30 by fixing bolts 29. The electric motor 25 is also supported by the support legs 31 with respect to the fixed base 30.

A mechanical seal 33 is provided between the centrifugal impeller 40 and the central portion of the casing cover 3, and the drive shaft introducing hole 27 is formed by the mechanical seal 33.
And the drive shaft 26 is kept liquid-tight.

A drainer plate 34 is attached to the drive shaft 26 at a position where it is led out from the casing cover 3, and in the unlikely event that liquid leaks from the mechanical seal 33, the drive shaft 26 is transmitted to the electric motor 25. The liquid that is about to enter is shaken off by the draining plate 34 by centrifugal force to prevent it from entering the electric motor 25.

A discharge port 35 for discharging the liquid shaken off by the draining plate 34 is opened in the lower portion of the bracket 5. The centrifugal impeller 40 will be described with reference to FIGS. 3 and 4. This centrifugal impeller 40 is also PPE
It is made of synthetic resin such as resin and has a semi-open structure. That is, the centrifugal impeller 40 integrally has a back plate 41 and a plurality of blades 42 arranged in a radial direction on the front side of the back plate 41 and extending spirally, and between the adjacent blades 42. A spiral passage 43 ...
Has been formed.

In this case, each blade 42 of the centrifugal impeller 40 ...
The front edge thereof has a tapered portion 42a inclined with respect to the back plate 41, and a parallel portion 42b parallel to the back plate 41 continuing from the tapered portion 42a to the outer periphery. Further, each of these blades 42 is located on the rear surface side b (the front surface side is indicated by a) in the rotation direction (the arrow X direction), and extends from the parallel portion 42b to at least a part of the tapered portion 42a. Flat surface 44 parallel to the back plate 41
Has been formed. The flat surface 44 is formed so as to be flush with the parallel portion 42b and is an extension surface of the parallel portion 42.

At the center of the centrifugal impeller 40, a mounting hole 46 through which the drive shaft 26 is passed is formed. A metal cylinder 47 is inserted into the mounting hole 46 for reinforcement.

The mounting hole 46 of the centrifugal impeller 40 is inserted through the tip of the drive shaft 26, and a fixing nut 48 is screwed onto the tip of the drive shaft 26 to tighten the centrifugal impeller 40.
Is fixed to the drive shaft 26. In this case, the drive shaft 26 is formed with a step portion 26a for restricting the mounting position of the centrifugal impeller 40, and an adjusting shim 49 is inserted between the step portion 26a and the centrifugal impeller 40 as necessary. As a result, the mounting position of the centrifugal impeller 40 is adjusted.

The impeller 40 attached to the drive shaft 26 is installed between the guide vane 4 and the casing cover 3. In this case, each blade 42 of the centrifugal impeller 40
Tapered portion 42a formed on the front edge of ... And parallel portion 4
2b faces the guide vane 4 with a predetermined gap G between the guide vane 4 and the guide vane 4.

The operation of the embodiment having such a structure will be described. When adjusting the gap G between the front surface of the blade 42 and the guide vane 4, the centrifugal impeller 40 is passed through the drive shaft 26, and the fixing nut 48 is tightened.
As shown in FIG.
The A dimension up to the blade front surface of 0 and the B dimension from the inner surface of the casing cover 5 to the back surface of the guide vane 4 are measured, and the difference B−A = G is obtained. At this time, when the value of B-A does not reach the predetermined gap G (usually 0.5 to 1.5 mm), the adjusting shim 49 is interposed between the step portion 26a of the drive shaft 26 and the impeller 40. The thickness of the adjusting shim 49 is adjusted to adjust the G dimension.

In the case of such a dimension measurement, in the case of the impeller 40 in which the outer diameter of the impeller 40 is sufficiently large and the parallel portion 42b exists, the parallel portion 42b is used as the measurement reference plane and the wall surface of the casing cover 5 is used. The dimension A can be measured by measuring the dimension with the parallel surface 42a.

Further, in order to change the pump output, when the outer diameter D of the centrifugal impeller 40 is cut to reduce the diameter of the impeller 40, or when the parallel portion 42b is cut and is not left, The flat surface 44 formed on the tapered portion 42a can be used as a measurement reference surface. That is,
The dimension A can be measured by measuring the dimensions of the wall surface of the casing cover 5 and the flat surface 44.

Therefore, the dimension of the gap G can be measured, and the pump performance can be adjusted with high accuracy by adjusting the thickness of the adjusting shim 49. Moreover, the flat surface 44
Is formed on the rear surface side b of the blade 42 in the rotation direction (arrow X direction), and the tapered portion 42a is left on the front surface side a of the blade 42, the gap between the tapered portion 42a and the guide vane 4 increases. Therefore, water leakage is prevented from increasing from here, and there is no risk of deterioration of pumping characteristics.

In the above embodiment, the blade 42 has a shape having a tapered portion 42a and a parallel portion 42b following the tapered portion 42a. However, the shape of the blade 42 is different from that of the other embodiment shown in FIG. As described above, even in the case where only the tapered portion 42a is provided and the parallel portion 42b that follows the tapered portion 42a is not provided, the rear surface side b (the front surface side is a on the front side is a) in each blade 42 ... (Shown), and a flat surface 44 parallel to the back plate 41 may be formed.

Also in this case, the flat surface 44 can be used as the measurement reference surface to measure the A dimension, and the gap G can be accurately measured. Further, in the above-mentioned embodiment, the example in which the guide vane 4 is integrally formed with the casing cover 3 has been described, but the guide vane 4 and the casing cover 3 may be separately formed and connected to each other. Further, although the example in which the bracket 5 is also formed integrally with the casing cover 3 has been described, the bracket 5 and the casing cover 3 may be formed separately and connected to each other.

[0035]

As described above, according to the present invention, since the flat surface parallel to the back plate is formed in the tapered portion of the blade,
The flat surface can be used as the measurement reference surface to measure the A dimension. Therefore, the gap G between the guide vane and the blade can be accurately measured, and the output can be adjusted with high accuracy. Moreover, since the flat surface is formed on the back side in the rotation direction of the blade and the taper portion is left on the front side, the gap with the guide vane does not increase, it is possible to prevent an increase in water leakage, and improve the pumping characteristics. There is no risk of adverse effects.

[Brief description of drawings]

FIG. 1 is a sectional view of a centrifugal pump showing an embodiment of the present invention.

FIG. 2 is a gap G between the guide vane and the blade of the embodiment.
The expanded sectional view of the principal part explaining FIG.

FIG. 3 shows an open type centrifugal impeller of the same embodiment, (A) is a front view and (B) is a sectional view.

FIG. 4 shows an open type centrifugal impeller of another embodiment of the present invention, (A) is a front view and (B) is a sectional view.

FIG. 5 shows a conventional open type centrifugal impeller, where (A) is a front view and (B) is a sectional view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Synthetic resin pump casing 2 ... Suction port 3 ... Casing cover 4 ... Guide vane 6 ... Bracket 18 ... Discharge port 25 ... Electric motor 26 ... Drive shaft 40 ... Synthetic resin open type centrifugal impeller 41 ... Back plate 42 ... Blade 42a ... tapered part 42b ... parallel part 44 ... flat part 46 ... mounting hole 49 ... adjustment shim

Claims (2)

[Claims] 1. A guide vane is provided in a pump casing made of synthetic resin, a centrifugal impeller made of synthetic resin is installed facing the guide vane, and the centrifugal impeller is provided at the center of the centrifugal impeller. The rotating impeller is connected to the centrifugal impeller, and the centrifugal impeller is provided with a large number of vanes that are arranged substantially in the radial direction and extend spirally on the front surface of the back plate, and the height of these vanes decreases toward the outer peripheral direction. In an open-type impeller pump having a tapered portion and opening the front side of these blades, the tapered portion of the blade has a rear plate located on the back side in the rotation direction. A synthetic resin centrifugal pump having parallel flat surfaces. 2. The outer peripheral portion in which the blade is connected to the taper portion,
In the case of an open type impeller formed by forming a parallel portion parallel to the back plate, the flat surface formed on the tapered portion of the blade is formed on the same surface as the parallel portion. Centrifugal pump made of synthetic resin.