DE1453715A1 - centrifugal pump - Google Patents

Description

Priority: U.S.A. dated December 7, 1962 Ser "No. 24-3

and April 15, 1963 Ser _o No. 273 164-

The invention relates to centrifugal or centrifugal pumps, and particularly relates to such Pumps that are used to convey liquids that contain solid or fibrous materials «

It had long been a problem in the hydraulics industry with centrifugal pumps, solid or semi-solid or fibrous materials, hereinafter collectively referred to as "solid materials" are to be designated which are contained in a liquid, to convey or to pump, because these materials threaten to clog the impeller of the pump »Tried despite this problem

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But you have to promote more and more liquids that have more and larger solid constituents.

One way to solve this problem was to use a standard centrifugal pump with an impeller to be provided, which lies in a recess formed in the pump chamber, so that through the rotating impeller creates a vortex in the pump chamber. The impeller is in its recess mounted in such a way that it is at a distance from the opposite wall of the pump housing which is the diameter of the pump inlet is equal so that any solid material entering the pump chamber is through the pump outlet can escape without it coming into contact with the blades of the impeller.

Although pumps of this type have been successful in some ways, they have the disadvantage of being only one can deliver a certain pressure and that their efficiency is extremely low. It lies because a fluid vortex is created in the pump chamber by the impeller blades located in the recess is generated, with the swirling liquid acting on the incoming liquid and the liquid to be conveyed solid material exerts a counterforce. This will

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caused a considerable loss in both efficiency and pressure generated. therefore pumps of this type are only used when it is absolutely necessary, to convey solid materials with such dimensions that clog a conventional centrifugal pump would.

An aim of the present invention is to overcome the drawbacks and problems mentioned with pumping of solid materials contained in liquid by a special design of a centrifugal pump 21, which is provided with an impeller, the blades of which are in the pump chamber, yet any solid material entering through the pump inlet without clogging can be funded,

According to the present invention is a centrifugal pump with an impeller chamber, which with is provided with an axially lying inlet and a tangentially lying outlet, as well as with one rotatably mounted in the chamber impeller, which has a rear cover plate, which at a distance mutually lying, essentially radially extending and axially extending blades, characterized in that the barrel ««

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wheel blades each at least partially across grasp the impeller chamber and in doing so in have a depth in the axial direction, aie on the radially outer part of the blade Has a maximum and decreases towards the radially inner end of the blade, the blades together with the cover plate and the wall of the impeller chamber, a plurality of continuous Form channels which lead from the inlet to the outlet j

of each channel where the smallest dimension / at least one sphere is equal to the diameter of the chamber inlet.

In this way, the continuous channels prevent the pump from becoming clogged can, because these channels, their dimensions a sphere with the diameter of the pump inlet ensure that any solid material that enters the pump chamber through the inlet can occur, will also get through the impeller chamber to the outlet without clogging the pump.

The radially outer parts of the blades preferably have a depth in axial viewing which is essentially the axial extent of the

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Impeller comer is the same, with the maximum axial depth of each blade is preferably provided in the vicinity of the impeller circumference »

It is also preferred that the leading edge of each vane is toward and away from the cover plate gently curved away over its entire length and has the shape of a fillet.

The peripheral edge of the blade can be parallel to the running axis »In addition, the top plate of the running wheel is preferably with a Front surface on which the blades sit, provided, which curves towards the pump inlet, so that they are furthest in the axial direction at the impeller hub Direction protrudes.

The Laufradkaemer points in the radial direction substantially parallel walls.

Another »feature of the pump according to the invention is provided for the purpose of being able to properly convey special solid materials, such as e.g. long, sab.es material, composed for example of rags or rags, and which enters the inlet in greater lengths.

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For this purpose, the pump impeller can be moved axially between the normal front position, in which the vanes lie essentially entirely within the pump chamber, and one back jpiogene Position can be adjusted in which the blades are essentially completely out of the Impeller chamber are pulled out »

The impeller is preferably seated on a shaft which is displaceable in an axial direction Is mounted bearing and is connected to an adjustment device with which an axial movement of the Shaft between the advanced and retracted positions can be effected »This adjustment device preferably has a bearing sleeve which rotatably receives the shaft and on a relative Movement in the axial direction with respect to the shaft is prevented »The bearing sleeve can be moved in a bearing bracket, which is connected to a housing of the pump, with means being provided with which the bearing sleeve can be moved in the axial direction *

The bearing sleeve can be moved in the axial direction relative to the Lggprkonsole by means of a threaded device adjusted, which can be rotated on the sleeve. and attacking the console, or it may

a hydraulic device may be provided, 90 $ 80e / Q411

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The invention is shown, for example, in the accompanying drawing and is described below explained in detail «

Fig. 1 is a cross section through a centrifugal pump according to the invention «

FIG. 2 shows an end view of the pump according to FIG. 1 in the direction of the lines II-II of FIG.

Fig. 3 is a corresponding end view of a modified one Embodiment.

Fig. 4 shows in a diagram the plot of the pressure level in percent and the efficiency over the impeller displacement with constant pump delivery.

Fig. 5 shows a diagram of the delivery rate, the pressure head and dan efficiency of a Pump according to the invention at 1150 rpm with fully retracted, 50% retracted and impeller not withdrawn.

According to Fig. 1, a centrifugal pump designated as a whole with 9 is verse with a pump housing 10

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hen ₉ having an inlet i1 and a tangentially located outlet 12 has _β The Pumpengenau.se encloses an impeller chamber 13 ', in which a designated throughout vrjt 14 impeller is mounted in a normal posture "The LaiifradJkaMtier 13 is provided with a spiral casing 15, which summarizes the outlets of the impeller and directs them to the pump outlet 12 »

The impeller 14 is connected to a shaft 17 ".;, which extends from the pump housing 10 to the rear, where it is connected to a drive, not shown connected is. Bie shaft 17 is with a usual Sleeve 16 and a suitable seal, which is shown as a stuffing box 18, which includes the usual packing 19 and the gland follower 20 has. The shaft 17 is rotatable in a bearing sleeve 23, which in turn is rotatable in a bearing bracket 24 is arranged, as will be explained further below. This bearing bracket 24 is in turn connected to the pump housing 10, which is attached to a base plate 25 «

The centrifugal pump is also provided with a rear cover 28 which encloses the stuffing box 18 and is secured within a cylindrical portion 350 of the pump housing 10. The part 30 is

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so long that in the position shown of the rear cover 28 there is enough space to pull the impeller completely out of the impeller chamber 13 and to accommodate it in part 30.

The impeller 14 is provided with a rear cover plate 29 which has a hub part 39 with an axial bore 40 which is provided with a thread and which is screwed onto the end of the shaft 17 . The cover plate 29 carries on the front surface in the circumferential direction spaced radial blades 35 which protrude in the axial direction. The front surface of the cover plate curves forward towards the inlet 11 and protrudes furthest forward at the hub 30.

The blades 35 extend in the radial direction up to the circumference of the cover plate. As indicated at 42 in FIG. 2, they have essentially the same thickness over their entire length, although this can of course be changed .

Each blade 43 has "on the radially outer part of the blade has a maximum in the axial direction and a depth decreases towards the radially inner end of the blade, as to ER- ea in Fig. 1

BATH

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is known, so each blade has its maximum in the vicinity of the circumference of the impeller Depth in the axial direction, which in the v / es borrowed from the axial extent of the chamber 13 is equal to " The run of the blades decreases to the hub 39 of the cover plate to zero.

The gate edge 46 of each blade 35 is shaped so that _? when the impeller is in its normal working position according to FIG. 1, in which the leading edge of each blade almost rests on the opposite wall 36 of the chamber, the blades together with the cover plate 29 and the wall 36 of the impeller chamber have a plurality of continuous channels 45 form, which extend from the inlet Ή to the outlet 12 of the pump. The minimum dimension of each such channel 4-5 corresponds to at least one sphere with the diameter of the pump inlet 11.

By this design, any solid material that enters the inlet 11 of the pump can be on any these continuous paths pass through the impeller chamber and into the outlet, regardless of the instantaneous position of the rotating impeller.

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Said minimum dimension of the channels 45 is made possible by the fact that the leading edge 46 each Blade 35 viewed in the radial direction gently and continuously from the cover plate over the entire length 29 is away and curved towards the plate. From the hub 39 of the impeller where the arc distance between adjacent blades is very small and where the distance between the leading edge is 4-6 each Blade and the opposite wall 56 of the Impeller chamber is substantially equal to the diameter of the inlet, the leading edge curves each blade gently progresses away from and approaches the cover plate as it advances radially the opposite wall 36 "so that the curvature the front edge assumes the shape of a fillet, as can be clearly seen in FIG. 1. At the Circumference of the impeller, the leading edge 46 of each blade is very close to the wall 36 »

The peripheral edge of each blade is parallel to the axis of the impeller. One moving in a radial direction extending part of the wall 36 dea? Impeller chamber lies essentially parallel to a radially extending part of the rear wall of the chamber on the spiral housing 15 "

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I ¹ Ig. 1 shows, in dash-dotted lines, how a theoretical ball with the diameter of the pump inlet 11 moved through the impeller chamber along a channel 4-5 Blades 35 can move, and that a part of the ball extends from the leading edge of each blade inward to the cover plate 29. In this position, it does not take as much space between the leading edge 46 and the wall 36 to pass a ball of the dimensions of the inlet. To this end, the leading edge of each vane can come closer to the opposite wall surface as one progresses radially outward. The curvature at the leading edge of each vane continues until a point is reached where the distance between adjacent vanes equals that Is the diameter of the inlet 11 or the diameter of the theoretical sphere that is moved through the pump. At this point, the depth of the blades 35 has a maximum in axial direction and is essentially the same as the axial extent of the impeller chamber 13.

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In some applications there is the one to be promoted Material made of long, tough material, such as Rags or intestines of animals. Such Materials have a tendency to wrap themselves around the impeller blades and into the narrow ones Wedge spaces between the blades and the opposing wall 36 · This The problem arises with the centrifugal pump according to the invention. overcome that impeller in the axial direction between its normal forward position in which the blades are essentially completely within the impeller chamber (Fig. 1), and a retracted position can be adjusted in which the blades are essentially pulled out of the impeller chamber are so that the distance between the opposing wall 36 and the leading edges 4-6 of the Impeller blades can be changed to remove any clogging between the impeller and the walls to prevent the impeller chamber.

In the embodiment shown in FIG A pump according to the invention, the Lggrhülse 23, which is slidably mounted in the bearing bracket 24- is prevented from moving relative to the shaft 17 in the axial direction, wherein

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an adjusting device is provided, which is designated as a whole by 49 and the bearing sleeve 23 move relative to the bearing bracket 24 in the axial direction and at a certain point can determine after the desired adjustment.

The adjustment device 49 has a splash

50, which is connected to the bearing sleeve 23 and protrudes therefrom in the radial direction, this flange 50 being provided with a bore 51 is unidirectional with a threaded hole 53 in a flange 52 of the L ^ pr Konsole 24 lies. A screw 54 fits through the bore

51 in the flange 50 and engages in the thread the bore 53 in the flange 52, so that upon rotation of the screw 54 in the bores 51 and 53 a relative axial movement between the Bearing sleeve 23 and the bearing bracket 24 is effected. A nut 55 is screwed onto the screw 5 ^, which is looked against the flange 50 in order to block the adjustment device 49, thereby also the bearing sleeve 23 in a desired position is being held.

With the help of this adjusting device 49, the impeller can be somewhere between in the axial direction a completely "closed" position, which in

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Fig. 1 is illustrated in solid lines, and one fully withdrawn or open position can be set, indicated by dash-dotted lines in Fig. 1 and with the reference number 1V is provided «In this position the cover plate 29 is almost on the rear Cover 28 on. An intermediate position in which the impeller is roughly in the middle between the perfectly withdrawn and fully closed position is shown in Fig. 1 as well indicated by dash-dotted lines and given the reference numeral 14 ″;

The spiral housing 15 of the pump shown in FIGS. 1 and 2, with which the from the impeller exiting material is guided to the tangential outlet, as is clear from FIG appears to be precisely circular in shape, however, the impeller according to the invention can also be used with a pump that has a conventional, really spiral-shaped housing as provided in Fig. 3, although the circular shape of Fig. 3 with respect to the Avoiding clogging has better properties.

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In the modification shown in Hg. 3, the impeller blades are denoted here by 48 are curved backwards in the radial direction as one progresses towards the impeller circumference. This vane shape corresponds to the usual practice with centrifugal pumps and continues to carry helps to improve the hydraulic efficiency of a pump according to the invention Here, too, every blade 48 has the same Front edge as described in Fig «1»

In a centrifugal pump according to the invention, when the impeller starts to rotate, Liquid 'with the solid in it Material sucked through the inlet 11 is then subjected to the action of the impeller and flows outwards in a radial direction, as is the case with the known centrifugal pumps is. The solid material in the liquid moves through the impeller chamber 13 along the channels 45 between the blades 35 »the Wall 36 of the chamber and the de & plate 29 are formed will. In this way, any solid material the size of which has an entry into the Inlet 11 of the pump allows through the impeller

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cash? and operated in the outlet without the pump is clogged and the pumping action is impaired.

If the axial position of the impeller 14 in the chamber 13 is to be changed, the nut 55 of the adjustment device 49 released and the Screw 54 is turned in the correct direction to adjust the relative position of bearing sleeve 23 and bearing bracket 24 to change. Example entry when the impeller is to be removed from wall 36, screw 54 is counterclockwise rotated, and then the nut 55 is pulled back against the Hansen 50, with the Bearing sleeve and thus also shaft 1? and the impeller 14 are moved away from the wall until the flange 50 on the head of the screw 54 to the plant comes. The adjustment device, the sleeve 23, the shaft 17 and the impeller 14 are thus in the correct position blocked. In order to move the impeller closer to the wall 36, again the nut 55 is loosened and the screw 54 is in Rotated clockwise so that the flange 50, the sleeve 23, the shaft 17 and the impeller to the wall 36 are moved. When the desired setting is achieved, the nut becomes 55

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again against the flange. 50 drawn to the To hold sleeve 23 at the relevant point »

The results of test runs of a centrifugal pump according to the invention at II50 IT / min are summarized in the diagram in FIG. The three solid, downward sloping curves indicate the dependence of the pressure head and flow rate and are labeled "not withdrawn", "50% withdrawn" and "100% withdrawn" to indicate the axial position of the impeller relative to the wall of the impeller chamber . They correspond to the three wheel positions indicated in FIG. 1. In the non-retracted position, the impeller is in the fully extended in Fig. 1 "position shown, at which 50% retracted position the impeller assumes the position 14 * ^l, while the fully retracted position is indicated in Fig. I 14 ' , in which the impeller lies fully in the 3D rope. The pump efficiency is indicated by the dashed lines A, B and G drawn over the other three lines. The latter curves show that in the transition from the non-withdrawn to the fully

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in the retracted position, an efficiency loss of about 7% occurs. The percentage Loss of efficiency occurred approximately

The moderate loss in head caused by the. Curves of Fig. 5 is indicated is a significant advantage, since the pressure height of a Systems against which the pump of this type usually works, usually essentially remains constant. If the line DE in the diagram is used as the pressure height of the system 55 ft (approximately 15 »2 m) is assumed, the Operate the pump in points F, G or H while still overcoming the pressure of the system. This means that the most diverse set-back positions of the impeller can be set up to fully retracted position, with the pumping height still large enough is to overcome the static head of the system, even if this is reduced with a TH? Delivery rate happens, which is specified in gallons per minute. With a common open pump, which is designed so that the impeller blades

»AD OBIQiNAL

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are close to the wall of the front cover, a similar retraction of the impeller would die Decrease head by about fifty percent so that the pump can reduce head in many applications of the system could no longer overcome. In the case of a non-clogging pump, there is a special one "Advantage of being able to follow the impeller

can almost withdraw desire and yet still / ilie full

Maintains print height.

In the diagram shown in FIG. 4, the characteristics of the pump according to the invention are plotted in a somewhat different manner. The two essentially flat, fully drawn-out curves show that, with a constant flow rate, the pump efficiency, measured from the point of maximum efficiency, and the pressure head generated decrease only very slightly when the opening or retraction of the impeller of QPJa progresses to 100%. These substantially planar or flat Euven demonstrate two main advantages of the present invention, namely the maintenance of the generated head to thereby maintain the flow of liquid against the head of the system and further the economics of power consumption

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by, the efficiency line is shown.

Below the two full lines in Hg. 4, another curve has been entered with broken lines which reveals the characteristics of another adjustable, open impeller pump of conventional design. It's over the dashed ktnsre for this pump that is denoted by X, it can be seen that with increasing opening or further retraction from zero the loss of head is very noticeable. Thus, the withdrawal represents the impeller in this pump is a very critical adjustment option, especially when the pump is part of a system that works against a fixed Print height works. Even a very slight retraction of the impeller in such a case The pump can interrupt the continuity of the flow unless other measures are taken be taken, such as accelerating the pump or reducing the pressure head of the system

Is is a feature of a centrifugal pump according to the invention that when the impeller of the

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opposite wall of the impeller chamber is withdrawn, the amount of pressure would not like to adopt following the experience with the conventional centrifugal pumps, drops sharply, but remains essentially the same, has been completely moved to the impeller from the chamber "Furthermore, remains also the efficiency of the pump about the same high value. These unusual and very desirable results are due, at least in part, to the special design of the impeller blades which actually exert a force on the swirling water in the impeller chamber as the water is forced out of the chamber in a radial sighting.

In the case of the pump according to the invention, essentially all of the pumped liquid enters the inlet of the impeller and is thrown outwards in a radial direction. If the "liquid is radial flows outwards, it also flows away. away from the rear cover plate of the impeller. However, in this one protrude Move the shovels further away from the cover plate and still act on the water, so that even now there is still a direct force on the

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Liquid is exercised. One can assume that this effect, which still occurs when the impeller is almost completely out of the chamber is pulled out, for the unusually high efficiency and the pressure height at all impeller positions responsible for.

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Claims (1)

Claims Λ Centrifugal pump with an impeller chamber that has an axially located liquid inlet and a tangential outlet, and with a rotatable in the impeller comb Impeller, which has a rear cover plate, the spaced apart, substantially radially extending and carries blades protruding axially, characterized in that the blades (35) each at least partially extend across the impeller chamber (13) and have a depth in the axial direction have "the" on the radially outer part of the Blade has its maximum and decreases from here mm radially inner blade end, so that the blades together with the cover plate (29) and the wall (36) of the Laufradkammtr a plurality of continuous channel files (4-5) form the inlet (11) to ana outlet (12) the pump range, the minimum dimension of each channel at least one ball with the Corresponds to the diameter of the inlet (11). 2 · Pump according to claim 1, characterized in that the radially outer parts of the blades (35) 909806/0411 have an axial depth which is essentially the axial extent of the impeller chamber (13) is equal to. 3. Pump according to claim 1 or 2, characterized in that each blade (35) in the vicinity of the impeller circumference has its maximum depth in the axial direction. 4. Pump according to claim 1, 2 or 3 »characterized in that that the leading edge (46) of each blade (35) over the entire length to the cover plate and is gently and continuously curved away from it, 5 · Pump according to claim 4, characterized in that the front, curved edge (46) of each blade (35) has the shape of a fillet. 6. Pump according to one of the preceding claims, characterized in that the peripheral edge of each Blade (35) is parallel to the axis of the impeller (14). 7 · Pump according to one of the preceding claims, characterized characterized in that the cover plate (29) of the impeller (14) has a front surface which the 909806 / OA 1 1 Carrying blades (35), and which curves forward to the Laufradkaimner (13), where they at the Have the impeller protrudes the furthest in the axial direction. 8. Pump according to one of the preceding claims, characterized in that the impeller chamber with im is provided substantially parallel, radial walls. 9. Pump according to one of the preceding claims, characterized in that the impeller in the axial Direction between its normal forward position in which the paddles (35) are essentially completely • lie innahalb the impeller chamber (13), and one retracted position is adjustable, in which the blades are essentially completely out of the impeller chamber are withdrawn. 10. A pump according to claim 9, characterized in that · the impeller (14) on a lle W _e (17), which is seated displaceably in the axial direction in a bearing, wherein the shaft is connected to an adjustment device with which an axial Movement of the shaft is made possible, so that the impeller between the front and the retracted position veretellt who can. SDS8O0 / O411 11. Pump according to claim 10, characterized in that the adjusting device has a bearing sleeve (23) in which the impeller shaft (17) is rotatable and is immovable in the axial direction, the bearing sleeve being displaceable in a bearing bracket (24) is mounted, which is connected to the pump housing, wherein further means (54,55,50,52) are provided with which an axial movement of the bearing sleeve (23) is effected. 12. Pump according to claim 11, characterized in that the bearing sleeve (23) i'n relative in the axial direction to the bearing bracket (24) is moved by a threaded part (54) which is rotatable on the bearing sleeve (23) sits and engages the bearing bracket (24). 13. Pump according to claim 11, characterized in that the bearing sleeve (23) in the axial direction by a hydraulic device is moved. 909806/0411