RU2583197C1 - Metering gear pump - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building, particularly, to gear-type dosing pumps with external engagement, and can be used for pumping and dosing chemically aggressive polymer solutions of aramid and other types of fibres and other liquid media. Metering gear pump consists of housing with inlet and outlet holes, drive shaft with seal made of antifriction material, upper and lower plates of gear mechanism, stator of gear mechanism, drive and driven gears, axis of driven gear, coupling bolts and coupling nut. Pump design additionally includes sealing sleeve of drive shaft made from antifriction material, guide sleeve with thread and coupling nut. Sealing sleeve is secured in guide sleeve. Gear mechanism with stator, upper and lower plates, drive gear fitted on drive shaft, driven gear installed on axis, is made of steel grades 10X17H13M2, 10X17H13M3T, 08X21H6M2T, AISI316T.

EFFECT: decreased wear rate of conjugated subject to friction parts of the pump and stabilisation of pump dosing characteristics.

1 cl, 4 dwg

Description

The invention relates to mechanical engineering, in particular to gear metering pumps with external gear engagement, and can be used for dosed supply of aggressive polymer solutions, including spinning machines that form chemical fibers in a wet and dry wet way, and other corrosive liquid wednesday

Known is a gear metering pump comprising a housing, a drive shaft and a gear mechanism fixed to the housing, all of whose details are made of martensitic steel grade EP890-Ш, heat-treated to hardness HRC≥56 (see copyright certificate SU No. 922316, class F04C 2/04 04/23/1982).

However, the above steel contains 11% chromium in the absence of nickel and is not corrosion resistant, therefore, when dosing chemically active media, the friction pairs of the pump quickly wear out. The shaft-housing coupling is most susceptible to corrosion and wear, since the electrode potentials of the metals of these parts are very different. This leads to the formation of a galvanic pair and acceleration of electrochemical corrosion and mechanical wear of tribological couplings, as a result of which the drive shaft wears out quickly, which leads to a change in the geometry of other tribological couplings. As a result, the metering characteristics of the pump no longer correspond to the set ones.

A gear pump is known, consisting of a housing, with external gearing gears housed in its cylindrical bores with trunnions installed in sliding bearings, end-face compensators with cuffs mating with the end surfaces of the gears, forming suction and discharge chambers with bores of the housing, inlet and outlet channels of the pumped fluids and cavities for lubricating bearings, portions of which are located on the end surfaces of the gears are connected to the suction chamber by channels, made and on the end surface of the compensators, while the inlet channel is made tapering, and the cavity sections located on the sides of the gears opposite from the end surfaces are connected by additional channels to the inlet channel (copyright certificate SU No. 1125407, class F04C 2/00, 11/23/1984) .

This design has limited operational capabilities due to the rapid wear of the bearing assemblies, an increased friction coefficient in the contact area of the pinion gears with sliding bearings, insufficient lubrication of the contact surfaces of the pinion gears and bearing holes and uneven pressing of the ends of the gears to the surfaces of the end compensators.

From the patent for utility model RU No. 39653, cl. F04B 17/00, 08/10/2004, a gear pump is known consisting of a pump housing made of self-lubricating material with a channel for supplying a pumped product, a channel for removing a pumped product and a support hole for a drive shaft, top cover of the gear mechanism, gear housing with drive and driven gears with external gearing, lower support plate and pump drive shaft with sealing washer.

The disadvantage of this pump is its low resistance to aggressiveness of the pumped product. So, in the process of manufacturing synthetic fibers, when pumping a polymer solution containing hydrogen chloride, the pump undergoes intensive wear due to its electrochemical corrosion, intensified by friction, which leads to a change in the geometry of the gears of the gear mechanism of the pump, resulting in a pump failure.

Known gear metering pump type 11NS, containing a cast iron housing with channels for solution inlet and outlet, a drive shaft, a gear mechanism with a stator, upper and lower covers, a drive gear mounted on a drive shaft, a driven gear mounted on an axis, an opening in the zone suction connected with the channel for the entrance of the solution and the hole in the discharge zone, connected with the channel for the exit of the solution (see Technical Specifications TU 92-02.22.075-91. Gear pumps for the production of chemical threads). Lubrication of the metal shaft – metal housing interface is carried out due to the entry into the friction zone of a metered product that is not a liquid, plastic or solid lubricant. Such lubrication is not effective for a pair of shaft-housing friction pairs and has no effect, since metals are in conjugation. In addition, if there is an alkali in the solution (during the production of viscose fiber) or hydrochloric acid (during the production of para-aramid fiber), the pump will fail due to:

- wear of the shaft and the bore of the housing due to their electrochemical corrosion, intensified by friction;

- wear of the shaft and the hole of the housing leads to a skew of the shaft in the housing and, accordingly, a change in the geometry of the mates of the gear mechanism of the pump, which, in turn, leads to an acceleration of wear of the parts of the mechanism. In this case, the pump loses its dosing characteristics and is decommissioned.

Closest to the invention in technical essence and the achieved result is the patent RU No. 2423620, class. F04C 2/08, September 29, 2009, from which a metering gear pump is known, consisting of a housing with inlet and outlet openings, a drive shaft with a seal made of antifriction material, upper and lower plates of the gear mechanism, the stator of the gear mechanism, the drive and the driven gears, the axis driven gear, coupling bolts and union nut.

The disadvantages of this pump is that the wear of the shaft and the bore of the housing leads to a skew of the shaft in the housing and, accordingly, a change in the geometry of the mating gear mechanism of the pump, which, in turn, leads to an acceleration of wear of the parts of the mechanism. In this case, the pump loses its dosing characteristics and is decommissioned.

The problem to which the present invention is directed, is to reduce the wear rate of the drive shaft, pump housing and stator, plates of the gear mechanism, drive and driven gears, increase the maintainability of the pump due to the possibility of replacing the sealing sleeve of the drive shaft.

The technical result of the claimed invention is a significant increase in the life of the gear metering pump.

The above technical result is achieved by the fact that the metering gear pump consists of a housing with inlet and outlet openings, a drive shaft with a seal made of antifriction material, upper and lower plates of the gear mechanism, the stator of the gear mechanism, the drive and the driven gears, the axis of the driven gear, the coupling bolts and a union nut, wherein the pump design further comprises a drive shaft seal sleeve made of an antifriction material and a threaded guide sleeve nut, where the sealing sleeve is fixed in the guide sleeve, and the gear mechanism with a stator, upper and lower plates, pinion gear mounted on the drive shaft, driven gear mounted on the axis, is made of steel grades 10X17H13M2, 10X17H13M3T, 08X21H6M2T, AISI316T.

The antifriction material from which the antifriction sleeve is made: fluoroplastic, polyamide, graphite, while the list of materials available for the manufacture of the sleeve is not limited to these materials.

Gear metering pump shown in figures 1-4 of the drawings.

FIG. 1 is a top view

FIG. 2 is a side view, section, where:

1 - pump housing,

2 - drive shaft

3 - the upper plate of the gear mechanism,

4 - stator gear mechanism,

5 - the bottom plate of the gear mechanism,

6 - pinion gear

7 - driven gear

8 - the axis of the driven gear,

9 - sealing sleeve,

10 - guide sleeve,

11 - union nut,

12 - coupling bolts,

13 - channel inlet,

14 - channel outlet.

FIG. 3 - section BB,

FIG. 4 - view A.

Distinctive features of the analogue and prototype are its following features.

1. The design of the pump contains a sealing sleeve of the drive shaft made of antifriction material, and a guide sleeve with a thread and a union nut, which allows replacement of the sleeve.

2. The gear mechanism with a stator, upper and lower plates, a drive shaft, a drive gear mounted on a drive shaft, a driven gear mounted on an axis, is made of steel preferably grades 10X17H13M2T, 10X17H13M3T, 08X21H6M2T, AISI316T, while the list of possible materials is not limited steel grades.

Production tests have confirmed the performance and increased life of the metering gear pump according to the invention.

The pump operates as follows.

The rotation of the drive shaft 2 is transmitted to the drive gear 6 and the pumped liquid is supplied through the channel 13 in the housing 1 to the suction area of the gear mechanism. From the suction region, the liquid enters the discharge region of the pump gear mechanism in the volumes formed by the tooth cavities of the pinion gear 6 and the driven gear 7 and the stator 4. From the discharge region of the gear mechanism, the fluid is removed from the pump through the channel 14. The drive shaft 2 rotates in the sealing sleeve 9, fixed in the guide 10 by means of a nut 11 and which is at the same time a sliding bearing for the shaft 2. The driven gear 7 rotates on the axis 8.

Test results on spinning machines of Kamenskvolokno OJSC of the gear metering pump according to the invention show the high efficiency of the described construction. The life of the gear metering pump increased by 2-2.5 times in comparison with the life of the known design. The maintainability of the pump is increased due to the possibility of replacing the sealing sleeve of the drive shaft.

Claims (1)

Dosing gear pump, consisting of a housing with inlet and outlet openings, a drive shaft with a seal made of antifriction material, upper and lower plates of the gear mechanism, the stator of the gear mechanism, the driving and driven gears, the axis of the driven gear, the coupling bolts and the union nut, characterized in that the pump design further comprises a drive shaft seal sleeve made of antifriction material, and a guide sleeve with a thread and a union nut, where the seal sleeve is closed eplena in the guide sleeve, and a gear mechanism with the stator, the upper and lower plates, a pinion gear mounted on the drive shaft, the driven gear mounted on the axle, made of steels 10H17N13M2, 10H17N13M3T, 08H21N6M2T, AISI316T.

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