DE1403881C

DE1403881C - Screw pump

Info

Publication number: DE1403881C
Application number: DE19601403881
Authority: DE
Inventors: Carl Oscar Torsten Stockholm Montelius
Original assignee: Aktiebolaget Imo-Industri, Stockholm
Priority date: 1959-02-03
Filing date: 1960-01-27
Publication date: 1973-03-29

Description

F i g. 3 in vergrößertem Maßstab einen Querschnitt durch einen Teil der Mittelschraube der Schraubenpumpe nach F i g. 1 und 2 mit ursprünglichem Profil der Gewindeflanke und erfindungsgemäßer Abschrägung, F i g. 3 shows, on an enlarged scale, a cross section through part of the central screw of the screw pump according to FIG. 1 and 2 with the original profile of the thread flank and bevel according to the invention,

F i g. 4 in Seitenansicht ein zweites Ausführungsbeispiel einer erfindungsgemäßen Schraubenpumpe undF i g. 4 shows a side view of a second exemplary embodiment of a screw pump according to the invention and

F i g. 5 einen Schnitt nach der Linie V-V in F i g. 4.F i g. 5 shows a section along the line V-V in FIG. 4th

Die in F i g. 1 und 2 dargestellte Schraubenpumpe weist einen Schraubensatz, bestehend aus einer Mittelschraube 1 und zwei Seitenschrauben 2 auf. Die Mittelschraube 1 hat zwei Schraubengänge mit konvexen Gewindeflanken; auch die Seitenschrauben weisen jeweils zwei Schraubengänge auf, die aber konkave Gewindeflanken haben. Die Schraubengänge sind in an sich bekannter Weise derart angeordnet und ausgebildet, daß sie an den Außenkanten zusammenwirkender Schrauben abdichten.The in F i g. 1 and 2 shown screw pump has a screw set consisting of a center screw 1 and two side screws 2. The central screw 1 has two screw threads with convex Thread flanks; the side screws also each have two screw threads, but they are concave Have thread flanks. The screw threads are arranged and designed in a manner known per se in such a way that that they seal on the outer edges of cooperating screws.

Der Schraubensatz 1,2 ist in einem diesen dicht umschließenden Gehäuse 3 untergebracht, das an seinem unteren Ende mit zwei symmetrischen Öffnungen 4 versehen ist, durch die das zu fördernde fließfähige oder flüssige Mittel einströmt; außerdem hat das Gehäuse 3 einen Flansch 5 zur Befestigung desselben mit dem Schraubensatz 1,2 innerhalb eines Pumpengehäuses 6 mittels Schrauben 7 derart, daß das untere Ende des Gehäuses 3 mit den öffnungen 4 sich in der Einlaßkammer 8 des Pumpengehäuses 6 und das obere Ende des Gehäuses 3, das in Achsrichtung oben offen ist und den Auslaß für den Schraubensatz 1,2 bildet, sich in der Auslaßkammer 9 des Pumpengehäuses 6 befindet.The screw set 1, 2 is in a tightly enclosing one Housing 3 housed, which at its lower end with two symmetrical openings 4 is provided through which the flowable or liquid agent to be conveyed flows in; also has the housing 3 a flange 5 for fastening the same with the screw set 1, 2 within a pump housing 6 by means of screws 7 such that the lower end of the housing 3 with the openings 4 is in the Inlet chamber 8 of the pump housing 6 and the upper end of the housing 3, the top in the axial direction is open and the outlet for the screw set 1,2 forms, is located in the outlet chamber 9 of the pump housing 6.

Bei diesem Ausführungsbeispiel wird die Mittelschraube 1 angetrieben; sie ist einstückig mit einer Antriebswelle 10 ausgebildet. Diese Welle 10 ist in einem am oberen Ende des Gehäuses 3 befestigten Lager 11 gelagert und erstreckt sich durch einen am Pumpengehäuse 6 befestigten Deckel 12 hindurch, um mit einem nicht dargestellten Motor verbunden zu werden.In this embodiment, the central screw 1 is driven; it is integral with a drive shaft 10 trained. This shaft 10 is in a bearing 11 fastened to the upper end of the housing 3 stored and extends through a cover 12 attached to the pump housing 6 to with to be connected to a motor, not shown.

Die unteren Enden der Schrauben sind in geeigneter Weise im unteren Teil des Gehäuses 3 gelagert.The lower ends of the screws are mounted in a suitable manner in the lower part of the housing 3.

Der erfindungsgemäße, den Schraubensatz 1,2 durchziehende, schraubenlinienförmige Kanal, durch den die erfindungsgemäß beabsichtigte allmähliche Kompression der Gas- oder Luftblasen im zu fördernden Mittel erreicht wird, wenn die kritische Geschwindigkeit bzw. Drehzahl überschritten wird, kommt dadurch zustande, daß die Mittelschraube 1 an derjenigen Gewindeflanke eine Abschrägung 13 aufweist, die bei Drehung der angetriebenen Mittelschraube 1 in der in F i g. 2 durch einen Pfeil angedeuteten Richtung nacheilt; die Ausbildung dieser Abschrägung 13 ist in F i g. 3 veranschaulicht, in der durch eine gestrichelte Linie das ursprüngliche Profil des zugeordneten Schraubengangs angedeutet ist.The helical channel according to the invention, pulling through the screw set 1, 2 to promote the gradual compression of the gas or air bubbles intended according to the invention Medium is reached when the critical speed or rotational speed is exceeded, this comes about it comes about that the central screw 1 has a bevel 13 on that thread flank which when the driven central screw 1 is rotated in the position shown in FIG. 2 direction indicated by an arrow lagging behind; the formation of this bevel 13 is shown in FIG. 3 illustrated in which by a dashed Line the original profile of the assigned screw thread is indicated.

Die mögliche Erhöhung der Drehzahl hängt hierbei von den Abmessungen der Abschrägung 13 ab; je größer diese Abschrägung gewählt wird, desto größer kann die Drehzahl gewählt werden. Die Größe der Kanäle, die durch die Ausbildung dieser Abschrägung 13 bestimmt wird, ist durch das hierbei zunehmendeThe possible increase in speed depends on the dimensions of the bevel 13; ever the larger this bevel is selected, the greater the speed that can be selected. The size of the Channels, which is determined by the formation of this bevel 13, is thereby increasing

ίο Lecken innerhalb des Schraubensatzes nach oben begrenzt, und diese Abmessungen sind für jeden Einzelfall von den jeweiligen Arbeits- bzw. Betriebsbedingungen der zur Verwendung kommenden Schraubenpumpe abhängig.ίο limited leakage within the screw set, and these dimensions depend on the respective working and operating conditions for each individual case depends on the screw pump to be used.

Um zu erreichen, daß während eines beliebigen Teils jeder Schraubendrehung jede Kammer mit einem durchgehenden Kanal in Verbindung steht, kann die Anordnung so getroffen werden, daß sich an einer Gewindeflanke eines jeden Schraubengangs einIn order to achieve that during any part of each screw rotation each chamber with a continuous channel is in communication, the arrangement can be made so that on a thread flank of each screw thread

ao solcher durchlaufender Kanal bildet.ao such a continuous channel forms.

Die in Fig. 4 und 5 dargestellte zweite Ausführung der erfindungsgemäßen Schraubenpumpe unterscheidet sich alleine dadurch von dem Ausführungsbeispiel gemäß Fig. 1 und 2, daß der durchlaufende Kanal durch eine in die konkaven Gewindeflanken der Seitenschrauben 2 eingefräste Nut 14 gebildet wird.The second embodiment of the screw pump according to the invention shown in FIGS. 4 and 5 differs from the embodiment according to FIGS. 1 and 2 solely in that the continuous Channel is formed by a groove 14 milled into the concave thread flanks of the side screws 2.

In den Zeichnungen sind erfindungsgemäßeIn the drawings are according to the invention

Schraubenpumpen mit zweigängigen Mittel- und zwei-Screw pumps with double-start medium and double

• gängigen Seitenschrauben beispielsweise dargestellt.• Common side screws shown for example.

Es ist ersichtlich, daß die Erfindung nicht nur auf derartige Schraubenpumpen beschränkt ist; sie kann auch bei anderen Schraubenpumpen mit anders zusammengesetzten Schraubensätzen oder mit ein- oder mehrgängigen Schrauben verwendet werden, ohne den Bereich der Erfindung zu verlassen, wenn man nur in an sich bekannter Weise dafür Sorge trägt, daß das Profil der Schraubengänge, die Anzahl der Seitenschrauben und die Anzahl der Schraubengänge so aufeinander abgestimmt sind, daß in jeder Stellung der Schrauben wenigstens eine im Prinzip geschlossene Kammer vorhanden ist.It can be seen that the invention is not limited only to such screw pumps; she can too with other screw pumps with differently composed screw sets or with single or multi-start screws Screws can be used without departing from the scope of the invention, if one is only in in a known manner ensures that the profile of the screw threads, the number of side screws and the number of screw threads are coordinated so that in every position of the screws there is at least one, in principle, closed chamber.

Es ist ohne weiteres erkennbar, daß die Erfindung nicht auf die in den Zeichnungen dargestellte Anordnung der durchlaufenden Kanäle beschränkt ist, sondem daß diese Kanäle sich auch auf anderen Gewindeflanken befinden können; vorteilhafterweise sollten aber bei den Seitenschrauben 2 die Nuten 14 nicht in dem in F i g. 5 mit 15 bezeichneten, mit einer kleinen Abflachung versehenen Schraubengangteil und bei der Mittelschraube nicht in dem in F i g. 2 mit 16 bezeichneten, mit dieser kleinen Abflachung der Seitenschraubengangteile zusammenarbeitenden Schraubengangteil der Mittelschraube 1 angeordnet werden.It is readily apparent that the invention does not apply to the arrangement shown in the drawings the continuous channels is limited, special that these channels are also on other thread flanks can be located; but advantageously in the case of the side screws 2, the grooves 14 should not be in the one shown in FIG. 5 designated by 15, provided with a small flat screw thread part and in the Center screw not in the one shown in FIG. 2 denoted by 16, with this small flattening of the side screw thread parts cooperating screw thread part of the central screw 1 are arranged.

Hierzu 1 Blatt Zeichnungen1 sheet of drawings

Claims

Claim:

Screw pump consisting of a central screw with convex screw flanks on the screw threads and one or more side screws' with concave screw flanks on the There is screw threads or on the screw thread in which the outer edges cooperate Seal the screws as much as possible so that the screw set is tightly attached to a housing part is enclosed and in which the side screw or side screws at the transition from the trailing The screw flank is or are flattened to the screw circumference, so that in every position of the Screw set at least one closed, of two screws and the wall of the housing part limited delivery cell is formed, which upon rotation of the screws axially from the inlet end of the screw set migrates to its outlet end, characterized in that at least one helical one running through the entire length of the screw set (1, 2) Channel is present, either by a bevel (13) on the trailing thread flank the center screw (1) or through a groove (14) in the thread flank of the side screw or screws (2) is formed.

3030th

3535

The invention relates to a screw pump, which consists of a central screw with convex screw flanks on the screw threads and one or more side screws with concave screw flanks at the screw threads or on the screw thread in which the outer edges interact more closely Seal the screws as much as possible so that the screw set is tightly enclosed by a housing part and where the side screw or side screws are at the transition from the trailing screw flank is or are flattened to the screw circumference, so that in every position of the screw set at least a closed pumping cell bounded by two screws and the wall of the housing part is formed which is caused by the rotation of the screws axially from the inlet end of the screw set to its outlet end wanders.

In other words, the invention relates to screw pumps in which the condition G - ng + η = 0 is met, where G is the number of threads of the central screw, η is the number of side screws and g is the number of threads.

Such known screw pumps are theoretically tight. When the delivery cell is formed on the suction side a vacuum is created that causes the pumping cell to fill. When operating the screw set At a speed below a certain critical value, the conveyor cell becomes complete filled with the funds to be promoted. This critical value depends on the design of the screws, the geometrical dimensions of the same, the design of the inlet, the special properties of the agent to be promoted, e.g. B. viscosity, vapor pressure, content of dissolved gases, etc., as well as the existing suction lift.

However, if this critical value is exceeded, the chamber is not completely filled because it a cavity forms or cavities in the medium to be conveyed, which fill with gas or air, the or which are given away by the funds to be funded. These gas or air bubbles follow the mean when it is promoted by the screw set from the suction side to the outlet side. Then at the On the outlet side, the delivery cell is opened and the medium suddenly changes to the pressure prevailing on the outlet side exposed, then these gas or air bubbles are quickly compressed, creating very annoying noises and vibrations are caused. The screw pump or other parts of the corresponding system can be damaged.

The invention is therefore based on the object of providing a screw pump of the type described at the beginning to train in such a way that the sudden compression of the gas or air bubbles when promoting above the critical Speed is avoided.

This problem is solved by; that at least one thread running through the entire length of the screw set, helical channel is present, either by a bevel on the trailing Thread flank of the center screw or through a groove in the thread flank of the side screw resp. -screws is formed.

The stated object has already been achieved in that a single, from the inlet side of the The pump can be provided on its outlet side with a looping passage through all the threads which results from a certain mathematical formula (cf. German Auslegeschrift 1004930 and U.S. Patent 2693 763). This However, passage is created solely by a number of screw threads selected according to this formula and the number of screws as well as their dimensions and in particular the shape of the screw threads, whereby a set of screws is obtained which, in purely theoretical terms, is inherently leaky.

In contrast, the invention is based on a screw set in which the number of screws and the screw threads and their dimensions are chosen so that the screw set theoretically is tight. Of course, there is also a small amount of leakage here, which in practice is unavoidable Play between the screws and between the screws and the housing is unavoidable is. The invention achieves that by a simple additional measure to the theoretically tight pumps which can only be achieved with the known pumps with considerable effort Advantages are achieved, which consist in the fact that these pumps are now also at speeds that are above the previous critical value, can be operated without disturbing noises or vibrations arise.

The following are based on the drawings without restrictive significance, two exemplary embodiments of a screw pump according to the invention shown. It shows

Fig. 1 shows a first embodiment of an inventive Screw pump in side view,

F i g. 2 shows a section along the line H-II in FIG. 1,