WO2018013010A1 - Single-stage centrifugal pumping unit - Google Patents

Abstract

A single-stage centrifugal pumping unit comprises a double entry pump with a housing, which consists of a base and a cover, manifolds, a rotor, and a volute. The volute is configured in the form of a separate, independent component. Parts of the outside surface thereof, which are intended to be accommodated in cradles provided for this purpose in the cover and the housing, correspond to the shape of the surfaces of said cradles. An impeller and the volute are replaceable as a pair. The parameters of the impeller and the volute in each pair are calculated to provide maximum efficiency while ensuring the requisite feed and pressure. The invention is directed toward providing a pumping unit which demonstrates peak efficiency in non-nominal modes while having a simplified design and being universal in nature.

Description

 "ONE-STAGE CENTRIFUGAL PUMP UNIT"

FIELD OF TECHNOLOGY

The invention relates to the field of mechanical engineering, namely to pumping units intended for pumping water, aqueous solutions, as well as oil, oil products and similar liquids through main, technological and auxiliary pipelines.

BACKGROUND OF THE INVENTION

From the catalog “Centrifugal oil pumps for main pipelines” under the general editorship of V.A. Golovin, M., TsINTIkhimneftemash, 1989, p.5, centrifugal horizontal single-stage pumps of the NM type are known for pumping oil through main pipelines, including a casing with a spiral by a branch, and, located in the case, the impeller of a bilateral entrance. The use of a spiral outlet in them is aimed at reducing the radial forces acting on the rotor, and, accordingly, at reducing vibrations and increasing the reliability of the pump, however, when such a pump is operated at feeds below nominal, pressure pulsations and pump vibrations increase, which leads to a significant decrease in its efficiency and reliability. These disadvantages of the known pumps are related to the fact that their design provides for the use of only one spiral outlet, designed only for the nominal mode, which entails energy losses during its interaction with the impeller, which is forced to work in a different mode, i.e. at feeds below or above nominal.

 It is known that centrifugal pumps use replaceable impellers designed for corresponding reduced or increased feeds, but despite the fact that replacing the impellers leads to a slight change in the fluid flow pattern and a slight increase in pump efficiency in the corresponding modes other than nominal, and some increase reliability of its operation in comparison with the operation of a pump with a wheel for rated operation, this measure is insufficient, since the design of the pump also provides of only one spiral tap, calculated only for the rated mode, which entails a loss of energy due to its interaction with the impeller, designed for a mode other than

SUBSTITUTE SHEET (RULE 26) rated. The energy loss in this case leads to an additional loss of efficiency of up to 8% with respect to the optimal combination of the impeller and the spiral outlet.

Patent RU 57393 U1 describes a centrifugal pump with an impeller of a two-way inlet, including a spiral outlet formed by cavities in the lid and in the housing, as well as a replaceable guide vane with 4 proposed design options. It is noted that the use of a guide vane in a replaceable unit with a double-sided impeller allows maximum efficiency in the _feed range from 0.3 Q _H0M to 1, 25 Q _H0M providing the required pressure, minimum radial forces and vibrations, because when calculating this block for the given parameters, the optimal flow part is obtained. However, the inlet and outlet in each described structural embodiment are designed for maximum feed, the input conditions of each impeller are consistent with the output conditions of the inlet, and the output conditions of each guide vane with the same spiral outlet, which is made in the form of cavities in the lid and case, which determines the same disadvantages as described above associated with the use of the same spiral outlet, because liquid energy is converted over the entire length of the outlet, which, in turn, is designed not for optimal, but for maximum supply. Even with optimal interaction between the impeller and the guide vane in such a pump, energy losses are inevitable, because after the fluid has passed through the impeller and the guide vane, it enters a tap designed for only one mode. In addition, if it is necessary to replace such an existing pump installed on the highway with a pump with other design characteristics, it is also necessary to dismantle the pipeline, which is a time-consuming operation requiring additional investment in the cost of a new pump, and the need to use guide vanes complicates the design pump, increases the cost of its manufacture and increases the adverse noise impact on the environment. SUMMARY OF THE INVENTION

The technical result of the present invention is the creation of a single-stage centrifugal pump unit with the highest possible efficiency in modes other than nominal, while simplifying its design and giving it versatility.

 2

SUBSTITUTE SHEET (RULE 26) The specified technical result is achieved due to the fact that the single-stage centrifugal pump unit includes a centrifugal single-stage pump of a two-way input, a drive motor, a coupling connecting their shafts, a support frame for mounting the pump housing and the electric motor, a housing consisting of a base and a cover, an inlet and outlet nozzle , a rotor with an impeller installed in the thrust bearings, and a spiral outlet, Moreover, according to the invention, the spiral outlet is made as a separate independent part whether, and the parts of its outer surface intended for placement in the lid and case made in the lodgements for this correspond to the shape of the surfaces of these lodgements, the impeller and the spiral outlet made in pairs replaceable, and the parameters of the impeller and spiral outlet in each pair are calculated at the maximum value efficiency (maximum efficiency) while ensuring the required flow and pressure. It is preferable to make replaceable spiral bends cast in the form of a single cast part with a dividing wall that separates the fluid flow in the direction of travel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by the following graphic materials.

 Figure 1 shows a General view of a single-stage centrifugal pump unit; figure 2 shows a section of the pump along the axis of the pipeline in a vertical plane; Fig. 3 shows a schematic layout of a cover, a replaceable flow part and a pump casing in a section along the axis of the pipeline in a vertical plane; figure 4 shows possible embodiments of interchangeable spiral bends with a constant external connecting profile and various internal hydrodynamic profile, designed for optimal operation and maximum efficiency.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To provide a comprehensive understanding of the essence of the present invention, the following description sets forth its numerous specific features.

 In accordance with the present invention, a single-stage centrifugal pump unit includes a drive motor 2, a centrifugal single-stage pump 1 of a two-way input (hereinafter pump), a coupling 3 connecting their output shafts, a pump casing 17, consisting of a base 6 and a cover 7,

 3

SUBSTITUTE SHEET (RULE 26) the inlet pipe 8 and the outlet pipe 9, the rotor 10 with the impeller 1 1, and mounted in the thrust bearings 12, a spiral bend 13, a support frame 5 for mounting the pump housing 17 and the motor 2. As shown in FIG. 3, the spiral bend 13 is made in the form of a separate independent part, and the parts of its external surface, intended for placement in the made tool holders 14 and 15 of the base 6 and the cover 7, correspond to the shape of the surfaces of these tool holders 14 and 15. The impeller 1 1 and the spiral bend 13 are pairwise interchangeable , etc whereby the parameters of the impeller 1 1 and the spiral outlet 13 in each pair are calculated at the maximum value of efficiency while ensuring the required flow and pressure. It is preferable to make replaceable spiral bends 13 cast, they may contain a dividing wall 16 for dividing the fluid flow in the direction of travel.

 The pump operates in the same way as other well-known centrifugal single-stage double-entry pumps. When the shaft 4 of the pump is rotated, the pumped medium through the inlet pipe 8 enters the impeller 1 1, as a result of the interaction of the blades of which with the flow of the pumped medium, the drive energy is converted into flow energy. From the impeller 1 1, the pumped medium enters a spiral outlet, where the flow is balanced, and then through the outlet pipe to the pipeline.

 The possibility of using a pair realized in the design of the pump

The “impeller - spiral bend”, which is designed and manufactured to operate in the optimum mode, helps to minimize the radial forces acting on the rotor, which, accordingly, contributes to the operation of the pump with low vibrations and increases its reliability.

 The advantage of the claimed invention regarding the possibility of using the same housing to obtain pumps with different characteristics is determined by the fact that the pump is a basic part and is a complex casting made of carbon or stainless steel, consisting essentially of a housing and a cover. Therefore, in the event of a change in the operating conditions of the pump (a decrease in pressure on an existing line, or a change in flow rate through an existing line), there is no need to ineffectively use an existing pump, or dismantle it and install a new one designed for new conditions. It is enough to install a new impeller-outlet pair, designed for new operating conditions, in an existing housing and get a pump with new corresponding design

 four

SUBSTITUTE SHEET (RULE 26) characteristics. Thereby, significant monetary savings occur due to the lack of the need to dismantle the old pump and manufacture a new pump in a new housing. The solution to the problem of obtaining a pump with new characteristics on the basis of the old one is especially relevant in connection with the absence of the need to dismantle the pipeline, but which the old pump is installed and operating.

 In addition, the possibility of replacing the impellers implemented in the pump, to use them in the optimal mode, allows to extend the life of the entire pump, because impellers are quickly wearing parts, and they can be made of expensive high-strength wear-resistant materials, for example, steel 20X13, 12X18H12MZTL, or similar steels and materials.

 Given that the pump housing connector is horizontal, it is possible to open, inspect, repair, replace individual parts of the pump and the entire rotor without dismantling the pipelines, as the pressure and suction nozzles of the pump are connected to the bottom of the pump housing.

INDUSTRIAL APPLICABILITY

 The present invention in the presented set of features can be applied to create a single-stage centrifugal pump unit with maximum efficiency in modes other than nominal, while simplifying its design, giving it versatility, durability, and ease of use.

5

 SUBSTITUTE SHEET (RULE 26)

Claims

CLAIM 1. A single-stage centrifugal pumping unit, comprising a centrifugal single-stage double-sided pump, a drive motor, a coupling connecting their shafts, the pump comprising a housing consisting of a base and a cover, an input and output nozzle, a rotor with an impeller mounted on it, mounted in the bearings bearings, and a spiral outlet, a support frame for mounting the pump housing and the electric motor, characterized in that the spiral outlet is made in the form of a separate independent part, and part of its external the surfaces intended for placement in the lodges and the pump casing made for this lodgment correspond to the shape of the surfaces of these lodges, while the impeller and spiral outlet are pairwise replaceable, and the parameters of the impeller and spiral outlet in each pair are calculated at the maximum efficiency while ensuring the required supply and pressure. 2. The single-stage centrifugal pumping unit according to claim 1, characterized in that the replaceable spiral bends are made in the form of a single cast part and contain a dividing wall that separates the fluid flow in the direction of travel. 6  SUBSTITUTE SHEET (RULE 26)