RU2482334C1 - Combined centrifugal gear wheel pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: pump contains the located in casing bores and engaged gears, which have annular bores near teeth roots with separators of suction and decreasing cavities located in them, at the front ends directed to the input there are centrifugal impellers preliminary engaged. There is, at least, one additional gear in casing bore that is engaged with neighbouring gears and equipped with centrifugal impeller preliminary engaged. In the places of engagement and disengagement with additional gear there are additional suction and decreasing cavities. The gears that are in double engagement have two separators of suction and decreasing cavities in annular bore near teeth roots, between which there are suction channels.

EFFECT: invention allows increasing the supply of combined centrifugal gear wheel pump without changing geometrical parameters of gear engagement and increasing the frequency of its rotation.

3 cl, 2 dwg

Description

The invention relates to mechanical engineering and relates to pumps used in oil systems of aviation gas turbine engines for supplying and pumping oil.

Known combined centrifugal gear pump (patent RU 2287087, IPC F04D 13/12, F04C 11/00 publ. 10.11.2006), containing installed in the wells of the housing and meshed gears, in which the tooth legs are made circular grooves with the separators of the suction and discharge cavities located in them, and the upstream centrifugal impellers are fixed at the ends facing the inlet. This pump does not allow to increase the oil supply without changing the geometrical parameters of the gearing (tooth module, gear width, diameter of the initial circumference) and speed.

The width of the gear (tooth length) has not only technological limitations, since at a high speed (centrifugal gear pumps operate at speeds of more than 10,000 rpm), the completeness of filling the interdental cavities with liquid when they pass through the suction zone deteriorates. Incomplete filling of the interdental cavities leads to pressure pulsations at the pump outlet and even to hydraulic shocks. To improve the filling of interdental cavities, an oil supply can be used on both sides of the gears, however, this significantly complicates the design of the centrifugal gear pump and increases its mass, which is unacceptable for the pump used in oil systems of aircraft gas turbine engines (GTE). An increase in the number of teeth in the pump gear leads to an increase in its dimensions and mass.

The objective of the invention is to increase the supply of a combined centrifugal gear pump without changing the geometric parameters of the gear mesh and without increasing the frequency of its rotation.

This problem is solved by the fact that in a combined centrifugal gear pump containing gear housings located in the bores and meshed, in which the tooth legs have ring grooves with separators for suction and discharge cavities located in them, and at the ends facing the inlet upstream centrifugal impellers are installed, according to the invention in the housing bore is located, which is meshing with adjacent ones and provided with an upstream centrifugal impeller, at least there is an additional gear bottom, and at the places of engagement with the additional gear and out of engagement with it, additional suction and discharge cavities are formed, and for gears that are double engaged, two separators of suction and discharge cavities are installed in the annular groove at the tooth legs, between which formed the suction channels. In addition, the input channels are made independent of each other; injection cavities are communicated with a common outlet channel.

Due to the fact that the gear, which is in double engagement, will participate in the transfer of the working fluid simultaneously to the two pressure zones, the pump flow increases approximately twice. (For example, a three-rotor combined centrifugal gear pump provides approximately the same flow rate as two two-rotor combined centrifugal gear pumps.)

The installation in the annular groove at the legs of the teeth of the gear teeth, which are in double engagement, two separators of the suction and discharge cavities with the formation of suction channels allows you to organize two suction cavities and provide a supply of working fluid to them.

The implementation of the input channels independent of each other allows for the pumping of the working fluid from different points, provided that the hydraulic resistance of the supply piping differs slightly.

The communication of the injection cavities with a common outlet channel allows to simplify the supply of the working fluid to the consumer.

Figure 1 is a longitudinal section of a three-rotor combined centrifugal gear pump.

Figure 2 is a section aa of figure 1.

The combined centrifugal gear pump contains a housing 1 in the bores of which gears 2 and an additional gear 3, which is central, are installed. All gears from the end facing the entrance are equipped with upstream centrifugal impellers 4. The same ring grooves 5 are made in each gear at the tooth legs, in which the separators 6 of the suction and discharge cavities 7 are installed, two are installed in the annular groove 5 of the central gear 3 with the formation of suction channels 9.

When the pump is operating, the torque from the drive shaft is transmitted to the central additional gear 3, and from it to the gears 2 that are engaged with it, together with the gears, the upstream centrifugal impellers mounted on their ends come into rotation 4. Under the action of the pressure developed by the impellers 4, the working fluid from three the inputs of the housing 1 from the suction zones 7 will enter the interdental cavities through the interscapular channels of the impellers and the annular grooves 5 in the gears 2, 3 and be transferred to the pressure zones 8, from where through a common vodyaschy channel delivered to the consumer. The suction cavities 7 are separated from the injection cavities 8 by the separators 6, and for the additional gear 3, the separators also act as a separator of the suction cavity, organizing the supply of the working fluid through the suction channels 9 simultaneously to the two injection cavities 8.

The implementation of the invention will increase the flow rate of the combined centrifugal gear pump without changing the geometrical parameters of the gear gear and without increasing its rotation frequency, which simplifies the design of the aircraft engine oil system by reducing the number of pumps required for pumping oil, and, in addition, reduces the mass of the engine.

Claims (3)

1. A combined centrifugal-gear pump containing gears located in the bores of the housing and meshed, in which the tooth legs have annular grooves with separators for suction and discharge cavities located in them, and upstream centrifugal impellers are installed on the ends facing the inlet, characterized in that in the bore of the housing is located at least one additional gear, which is in mesh with adjacent and provided with an upstream centrifugal impeller, and in max engaging the additional pinion and disengagement with additional cavity formed therein suction and discharge, wherein y gears are engaged in a double, the annular groove at the feet of the teeth has two separator suction and discharge cavities, which are formed between the suction ports. 2. The combined centrifugal gear pump according to claim 1, characterized in that the input channels are made independent of each other. 3. The combined centrifugal gear pump according to claim 1, characterized in that the discharge cavity is communicated with a common outlet channel.

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