RU2427725C2 - Submerged labyrinth-screw pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: pump includes rotor 3 on outer surface of which there are grooves 6, and housing 1 on inner axial surface of which there are grooves 2. On end surfaces of housing 1 there is inlet and outlet channel 12, 13. Blades 7 are provided on end surface of rotor 3 on the side of inlet channel 12. Pump inlet is connected to peripheral cavity 11 of blades 7, which is connected to inner cavity 16 of bowl-shaped sump by means of discharge holes 10 for impurities in housing 1 of pump. Bottom 8 of sump has tight connection 20 to inlet part of housing 1 of pump between discharge hole 10 for impurities and hole 9 located in housing 1 of pump as close to rotor 3 rotation axis as possible. Such pump design allows supporting constant pressure at the inlet, which guarantees cavitation-free mode, and allows avoiding repair work on replacement or cleaning of filter element. Absence of solid impurities in working fluid improves reliability and service life of pump operation.

EFFECT: higher reliability, longer cavitation-free operating mode and convenient operation of the pump.

1 dwg

Description

The invention relates to the field of engineering, in particular to hydrodynamic pumps, and can be used in systems for pumping liquids with the presence of solid particles, including for the fuel supply system of an internal combustion engine.

The submersible labyrinth screw pump is designed to supply a working fluid with a pressure and flow rate corresponding to small values of the speed coefficient (n _s = 5 ... 30), for example, for the injection system of an internal combustion engine, and can be used in industry and everyday life for pumping any liquids, preferably low viscosity.

Devices using a labyrinth-screw pump are widely used in technology. Known labyrinth pump driven by an electric motor (Golubev A.I. Labyrinth-screw pumps and seals for aggressive environments. Moscow. Mechanical Engineering, 1981, p.77). Labyrinth-screw pump allows you to provide optimal hydraulic parameters, namely flow rate, pressure of the working fluid and efficiency for devices requiring high pressure at relatively low flow rates of the working fluid. An example of its most preferred application is the fuel supply system of an injection internal combustion engine. However, the use of such an electric pump leads to large axial dimensions of the structure in comparison, for example, with vortex or centrifugal pumps.

Currently, vortex pumps are used in the fuel supply systems of injection internal combustion engines (German patent No. DE 3802057, 09/01/1988). The use of such a pump allows to reduce the axial overall dimensions of the pump in comparison with the labyrinth-screw described above. Its disadvantage is the complexity of the design. The performance of the vortex pump is highly sensitive to end gaps between the impeller and the side walls. Therefore, high demands are placed on the end surfaces and materials of these parts, such as wear resistance, high antifriction properties. In engineering, as a rule, the longevity of the pump when working with working fluids containing mechanical impurities is required. To protect the rubbing parts and the flow path from erosion wear, a filter is installed at the pump inlet. An example of this is the installation of an electric gas pump in the fuel tank of a car (German patent No. DE 10328591, 05/18/2006; Japanese application No. JP 07180632, July 18, 1995; Russian patent No. RU 2317436, February 20, 2008). The use of an inlet filter in this case guarantees the required operating conditions for the pump by the presence and size of solid impurities in the working fluid. The disadvantage of this pump design is the small overhaul cycle of the submersible pump. During operation, the filter gradually becomes clogged, and its throughput decreases, while the pressure drop increases. Because of this, the pressure at the inlet to the pump decreases and upon reaching a certain value, a cavitation mode of operation occurs, up to a complete failure of the pump. In addition, when the cavitation mode of operation occurs, an increase in the rotor speed and a decrease in fluid flow, which, in turn, can lead to a pump failure. In this case, the rotation supports are heated when the cooling deteriorates both themselves and the motor windings, if it is used as a drive. The use of such a device in the fuel supply system of an internal combustion engine leads to a decrease in reliability and a deterioration in the operating conditions of the vehicle as a whole.

Closest to the technical nature of the present invention is a submersible labyrinth screw pump for pumping liquids, containing a rotor, on the outer surface of which grooves of the rotating part of the pump are made, and a housing on the inner axial surface of which grooves of the non-rotating part of the pump are made, and on the end surfaces input and output channels (Russian patent No. 2265140, 11.27.2005).

It is well known that such a pump has a significantly larger gap between the rotor and the stator compared to the vortex, all other things being equal. Therefore, to ensure the long term of its cavitation-free operation, you can use a filter with a large mesh size, which will also increase the reliability and overhaul cycle.

Although this pump has better properties compared to other types, it does not completely exclude them. Therefore, the disadvantages of this design of the pump is the relatively low reliability of the support of rotation of the pump or resource, as well as the inconvenience of operation.

The lack of reliability and reduced durability of the product is explained by the fact that the pumped liquid, for example, in the case of automobile fuel, contains microparticles of rust from the walls of containers with a working fluid or solid impurities that enter the fuel tank when refueling a car, which, falling into rotation supports, significantly reduce the service life of the pump. In the case of using a filter at the inlet to the pump with small cells, a fairly fast “clogging” of it occurs. Thus, there is a decrease in pressure at the inlet and, as a consequence, a cavitation mode of the pump, due to which there is a decrease in fluid flow.

The objective of the invention is to increase reliability, ensure a long cavitation-free mode of operation and ease of operation of a submersible labyrinth-screw pump.

The technical result is achieved by the fact that in a submersible labyrinth-screw pump for pumping liquids containing a rotor, on the outer surface of which grooves of the rotating part of the pump are made, and a housing on the inner axial surface of which grooves of the non-rotating part of the pump are made, and on the end surfaces are made input and the outlet channels, according to the invention, blades are made on the end surface of the rotor from the input channel side, the pump inlet is connected to the peripheral cavity of the blades, which is connected it is connected to the inlet of the impurities in the pump housing between the discharge hole of the impurities and the hole located on the pump housing as close as possible to the axis of rotation of the rotor. The opening of the intake of the working fluid is located in the bottom of the housing as close as possible to the axis of rotation. An annular cavity is formed in the peripheral part of the blades, from which in the axial direction the flow is supplied directly to the pump inlet, and impurity discharge holes are made in the radial direction. The suction stream passing through the intake opening will be twisted by the blades. Extraneous impurities in the form of solid particles and viscous liquids having a high density, under the influence of centrifugal forces will be "discarded" to the periphery and discharged through the discharge holes, without penetrating into the annular inlet channel of the pump.

To collect foreign particles and impurities, a bowl-shaped sump is used. Prevention of the return of impurities to the opening of the intake of the working fluid is ensured by a tight connection of the bottom of the sump to the pump casing. The volume of the sump below the level of the discharge holes is selected so that its filling exceeds the required service life.

This design of the labyrinth-screw pump provides constant pressure at the pump inlet and a cavitation-free mode of operation with the simultaneous separation of impurities from the working fluid and the refusal to use an inlet filter.

The essence of the technical solution of the invention is illustrated by the example of a labyrinth-screw pump, shown in the drawing.

The submersible labyrinth-screw pump contains a housing 1, on the inner axial surface of which grooves of the non-rotating part of the pump are made — multi-thread 2, and a rotor 3 installed inside the housing 1 on the rotation supports 4 and 5, on the outer surface of which grooves of the rotating part of the pump are made - multi-start a thread 6, which with a thread 2 of the housing 1 forms a flow path of the pump. On the end surfaces of the pump, inlet and outlet channels 12, 13 are made. On the end surface of the rotor 3 from the side of the inlet channel 12, blades 7 are made. Inlet of the pump - inlet channel 12 is connected to the peripheral cavity 11 of the blades 7, which is connected to the inner cavity 16 of the bowl-shaped sump by holes 10 discharge of impurities in the pump housing 1, made opposite the peripheral part of the blades 7. The sump is formed by the outer wall 17, the bottom 18 and the inner wall 19. The bottom 18 of the sump has a sealed connection 20 with the input the bottom of the housing 1 between the hole 10 for the discharge of impurities and the hole 9 located on the bottom 8 of the housing 1 of the pump as close to the axis of rotation of the rotor 3. In the bottom 8 of the housing 1 mounted support rotation 4. The output channel 13 of the flow path of the pump is connected to the pressure line through holes 14 made in the sleeve 15.

In the working position, the pump is immersed in the working fluid, and its level should be at least higher than the hole 9. When the rotor 3 is rotated, the fluid will be pumped into the pressure line from the pump flow path to the outlet cavity 13 through the holes 14. Rotating blades 7 on the end face of the rotor 3 will spin the liquid, creating a vacuum at their root, and at the periphery an excess pressure. Thus, the working fluid with impurities will pass through holes 9 into the interscapular radial channels, where the flow will acquire both radial and peripheral speeds. In this case, a greater centrifugal force will be applied to the denser impurities, therefore, when they enter the annular peripheral cavity 11, they will inertia through the openings 10 will fall into the cavity 16 of the sump. The main stream will rotate axially in the annular inlet channel 12 and at the inlet of the pump flow path.

The flow rate from the openings 10 to the cavity 16 of the settler will decrease sharply, and solid particles under their own weight will settle on the bottom 18 of the settler. The volume of the cavity 16 of the sump below the level of the holes 10 should be such that it ensures the collection of impurities during the required life of the pump. The height of the wall 17 is determined so that solid particles are guaranteed to remain in the cavity 16 of the sump.

The present invention can be applied in many branches of mechanical engineering, since its introduction into production does not require special technology, and the economic effect can be significant.

Claims (1)

A submersible labyrinth-screw pump for pumping liquids, comprising a rotor, on the outer surface of which grooves of the rotating part of the pump are made, and a housing, on the inner axial surface of which grooves of the non-rotating part of the pump are made, and on the end surfaces there are input and output channels, characterized in that blades are made on the end surface of the rotor from the inlet channel, the pump inlet is connected to the peripheral cavity of the blades, which is connected to the bowl-shaped sump by means of openings of the discharge of impurities in the pump casing, the bottom of the sump having a tight connection with the input part of the pump casing between the hole for the discharge of foreign impurities and the hole located on the pump casing as close as possible to the axis of rotation of the rotor.