DE1528719A1 - Relief device for multistage centrifugal pumps - Google Patents

Description

Dipl.-Ing. Adolf H. 'Fischer Ludwigshafen a .Hh. Sichard-Wagner-Strasse 22

Relief device for multistage centrifugal pumps

The invention relates to a relief device for multistage centrifugal pumps which are arranged on the shaft a relief disk and in the housing a counterbalance disk, so that between these two disks a throttle gap is formed. Such relief devices are particularly at Boiler feed pumps known in various designs.

The device according to the invention now consists in that the throttle gap between the relief discs in the direction of the eratreociation of the shaft and somewhat inclined towards it, in such a way that it has a Conical surface forms.

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Once the invention has been made, the relief now train the facility in such a way that the Conical space resulting from the throttle gap after the pressure side expanded towards.

According to another embodiment of the invention, one proceeds in such a way that the cone space resulting from the Brosaelapalt narrows towards the pressure side *

In all of these designs it is in accordance with the invention advantageous to make the device so that the rotor of the pump, for the purpose of fixing the between Relief disk and counter disk used clearance, rests in a thrust bearing.

They are internal gas devices for centrifugal pumps known, in which liquid flows through an annular channel. ^ through a conical shaft end or is formed by a conical shaft attachment and a hollow cone of the bearing body and the expands in diameter in the direction of flow and narrows in the radial direction. Of the The gap should be changeable in such a way that the gap created in the gap by the centrifugal effect flow pressure acting on the cone in the axial direction with the increasing number of revolutions of the machine corresponding to the increase in the axial pressure of the conveyor also increases (German Patent 337 417).

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It should also be noted that when driving on the Pump characteristics are different axial ohms, which have an effect in each case by changing the radial throttle gap, if one does not counteract this in another way. The size of this known radial Throttle gap does not allow the sowing of a downstream pressure bearing bu, as to each axial movement of the rotor is associated with a proportional change in the radial throttle gap is.

In contrast to this, in a device according to the invention, where there is a conical throttle gap, depending on the angle that this Cone against the rotor axis includes axial rotor movement to a relatively small change of the throttle gap, i.e. with this conical design of the throttle gap one relatively large rotor movement a relatively small one Can assign gap change · So you get with the inventive design of the relief device a uniform pressure reduction, so that metallic contact with the relief section »which occurs in the event of disturbed operating conditions would be counteracted by a nachgesohltetes thrust bearing.

Further features of the invention emerge from the following description of exemplary embodiments in FIG Connection with the drawing and the claims.

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Figure 1 © ine erfisdungggsmäite loading device _s bsi which widens the bevel gear of the Bpoßselspalte after the pressure side »

Figure 2 shows the same direction, but with an aiob. cone space narrowing towards the pressure side,

FIG. 3 shows a known execution of relief 3S0heiben _r as a comparison with the embodiment according to the invention and FIG

FIG. 4 shows an enlarged illustration from FIG. 1.

Since it's only about the training of the relief device goes, the last stage of a centrifugal pump is only hinted at and not further designated.

In Figure 1, an embodiment according to the invention is shown in which the cone space resulting from the throttle gap widens towards the Drsack side. The two opposing disks, namely the counterbalance disk 1, which is fastened to the housing and the discharge disk 2, which belongs to the Hotor, also form a throttle gap 3 of length I, width s and axial width a.

In Figure 2 is the second possibility of a structural element according to the invention for the discharge device sketched, namely the one in which the cone space, which results in the throttle gap, after the pressure side narrowed. Between the counterbalance washer 1 * and the counterbalance washer 2 ' there is again the throttle gap 3 ″ which has the length L, a width s and an axial width a owns.

In Figure 3 is one of the known embodiments outlined by relief disks, with a counterbalance disk 4 and a relief disk 5 extending perpendicular to the shaft Throttle gap 6 is provided with a length L ^, a width s and an axial width a *. These known design represents an automatic, because between the disc and the counter disc is a very specific gap opens up in the normal Hegel range, i.e. with the usual load changes, hardly changed, so that it remains almost constant. But since, as is well known, of all safety devices, operational malfunctions can occur at times, e.g. very rapid Cause pressure drops on the suction side of the pump, as a result of a quick-action or failure the minimum quantity regulation can occur, as this is a Partial evaporation is associated with the discharge, can not be avoided with this known device that eil metallic Bevührm between the relief disc <and the counter, cheifee occurs.

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Dsisn immediately leads to a complete failure of the pump. It has 3I therefore beaüht "this game s ^ zoom and Nooh a Hotorföstlegur g with Help © bring about an axial bearing * However, in these known embodiments, the middle game sj very small _t change under normal operating conditions at Laständexu & gen game only negligible "If now the rotor defines additionally axially in a" such a relief device _£ there is a risk either the relief itself, or else the bearings »if necessary * oogar both to compromise, sumal during operation AUOH nor thermal and mechanical deformations occur which can then additionally change the game It 'BKiS at full thrust balance to the area, resulting from the difference D minua B ₃ ^ (Figure 3) gives _t act ice certain Ewisshendruck, ie · so tHe the gap I ₁ with the Width must oppose a certain flow resistance to the discharge water. It is known that the resistance can be influenced by changing the length of the throttle gap or its width, and it is also known that this resistance increases with increasing length and the same width, or with smaller width and the same length.

If you now carry out the formation of the relief device according to the proposal of the invention, and you keep the diameter D. D. and D " _e at, so must

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the intermediate pressure, since this relief is brought to the same pump, on the area D minus D.,

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be the same as in the known version according to Figure 3 · Since the length of the gap in the inventive design is greater than in the known embodiments, the width of the Brosaelspaltes in the goal stroke according to the invention greater than in the known designs and also the axial play, so that under the same operating conditions with the loading device according to the invention, there is a significantly larger axial play achieved. In FIG. 4, the gap 3 according to FIG. 1 is essentially shown enlarged and shown that a relatively small WinkeloO as a slope for the Cone against the horizontal is sufficient

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Claims (4)

Claims 1.) Relief device for multistage \ ^ y centrifugal pumps, in which a relief disc is arranged on the shaft and a relief counter disc are arranged in the housing, characterized in that the throttle gap between the relief discs runs in the direction of the extension of the shaft and is slightly inclined towards this that it forms a conical surface. 2.) relief device according to claim 1, characterized characterized in that the cone space resulting from the throttle gap widens towards the pressure side. 3.) relief device according to claim 1, characterized in that the throttle gap resulting cone space narrows towards the pressure side. 4.) Relief device according to claim 1 to 3, characterized in that the rotor of the pump, for the purpose of plaguing the between the relief disc and counter disk used clearance, rests in a thrust bearing. 109845/0205