RU182695U1 - Electric centrifugal semi-submersible pump unit - Google Patents

Abstract

The utility model relates to the oil and gas industry and can be used to pump liquids from drainage tanks into an oil recovery reservoir or other fluid receiver. The semi-submersible ETsND-D unit is installed in drainage tanks on the territory of site facilities or cluster sites. The result is achieved due to the fact that the declared ETsND-D unit has a semi-submersible design, which includes an electric motor and a pump part, inside which there are sections, which in turn consist of steps (guiding devices), where the impellers are located, assembled on a shaft, characterized by the presence of a flow chamber with an stuffing box, base plates with the main with a bearing and stuffing box units and a coupling basket with coupling joints of the motor shaft of the motor and pump located inside. The design of the unit allows you to change the flow and pressure indicators by using different sizes of the pump part, as well as changing the number of sections in the pump, leading to a decrease in the coefficient of vibration load and cavitation factor due to the lack of a long chassis.

Description

The utility model relates to the oil and gas industry and can be used to pump liquids from drainage tanks into an oil recovery reservoir or other fluid receiver.

Of the existing technical solutions for pumping liquid from a drainage tank, pumping units of surface, semi-submersible and submersible types are known.

Semi-submersible units are single-stage (single-section) and multi-stage (multi-section) type VND, VNTSS produced by Dimitrovgradkhimmash OJSC or MTR manufactured by GRUNDFOS.

The VNTSS unit manufactured by Dimitrovgradkhimmash OJSC includes a semi-submersible vertical centrifugal multistage pump and an alternating current electric motor. The unit is mounted on a base plate, which is installed on the neck of the drainage tank. The pump part consists of a housing and impellers mounted on the pump shaft. The pump part receives a rotational movement by means of shafts located in the chassis. With the help of an oil chamber with a double mechanical seal, the running gear is separated from the pump, the upper mechanical seal is cooled by oil. The running gear consists of shafts interconnected by half-couplings, bearings of the shafts are roller bearings, the shafts are located in airtight suspensions. The undercarriage receives rotational motion by means of a coupling connected to the motor shaft. The disadvantages of the technical solution and design are:

- metal consumption (high weight, a large number of parts);

- low power ratio (the ratio of the mass of the pump to its power);

- high loads on the suspension bearings due to the large mass of the structure;

- lack of forced lubrication of the bearing of the separator (closed-type bearings are used);

- increased cavitation factor of the unit as a whole due to the long undercarriage (several shafts interconnected by half-couplings);

- increased requirements for alignment due to the long chassis;

- a change in the immersion depth of the pump is achieved by changing the length and number of upper suspensions and shafts, which increases the cavitation factor;

- high price for the purchase of a pump;

- high financial costs for maintenance and operation (high specific energy consumption for pumping 1 m ³ liquid);

- the mandatory presence of an electric drive valve when using the unit in automatic mode (pump design involves starting on a closed valve);

- low efficiency (efficiency VNTSS-E-25 / 250-3,7-UHL1 is not more than 45%)

Closest to the claimed technical solution is a vertical centrifugal MTR submersible pump manufactured by GRUNDFOS, which consists of working chambers inside of which there are impellers mounted on the pump shaft and having slotted gaps between them, pipe connecting parts which together form one common discharge chamber, with a screw , a strainer for the receiving part of the pump, an end seal of the pump shaft, and an electric motor coupled to the pump by means of a plate coupling. The disadvantages of this technical solution is a sharp decrease in pressure characteristics and efficiency when pumping viscous fluids, design restrictions on the pressure at certain pump flows associated with the shape of the impeller, as well as its high purchase and maintenance price.

The technical problem to be solved by the claimed utility model is:

- pumping liquids from drainage tanks to the pipeline manifold with backpressure of the pump unit and changing, if necessary, power ratio of the pump by changing the number of impellers in the section;

- the use of different sizes of the pumping part of the unit to work in drainage tanks with different dimensions;

- the use of a wider range of flow-pressure characteristics without compromising the reliability indicator in comparison with analogues.

This problem is solved due to the fact that the claimed unit has a semi-submersible structure, which includes an electric motor and a pump part, inside which there are sections, which in turn consist of guide devices, where the impellers are located, assembled on a shaft, characterized by the presence of a discharge chamber with stuffing box, base plates with coupling and main baskets installed on it.

The technical result achieved in the totality of the above characteristics, as well as in comparison with various analogues, is the technical and economic effect.

The technical effect includes:

- the ability to change the flow-rate indicators of the unit due to the use of various standard sizes of the pump part, as well as changes in the number of sections in the pump;

- reduction of the coefficient of vibration and cavitation factor due to the absence of a long chassis;

- the ability to drain the pumped liquid in a given direction due to the presence of a flow chamber.

The economic effect includes:

- low manufacturing cost of the pumping unit due to the reuse of the basic part of the analogues (electric motor, taps, base plate, fasteners, instrumentation, sensors, control unit, controllers, part of the pump sections from the previously operated ESPs operated in wells);

- higher efficiency in comparison with aggregates of type VNTSS (table 1);

- low rates of specific rate of electricity consumption for pumping 1 m ³ liquid in comparison with aggregates of the type VNTSS;

- a high reliability indicator, which is formed on the basis of long-time MTBF.

The essence of the utility model is illustrated by the figure, which shows the assembly drawing of the unit. The unit consists of an electric motor 1 mounted on a coupling basket 2, inside of which coupling couplings of the motor shaft and pump 3 are located, a coupling basket 2 is connected to the main basket 4 by a bolt connection 5. To simplify the alignment of the mounting holes between the coupling and the main basket, a spike system is provided groove "6. In order to prevent axial runout of the shaft 7 in the upper part of the main basket 4 is the bearing assembly 8. The shaft 7 passes through the bearing assembly 8, the stuffing box 9 located in the main th basket 4, and the discharge pressure chamber 10 and is connected to the pump part 11 by means of a connecting coupling half. The main basket 4 serves to ensure safe and comfortable maintenance by the personnel of the stuffing box 9 installed on the base plate 12. For the directional removal of possible leaks from the stuffing box 9 back to the drainage tank 13, in the base plate 12, on which the main basket 4 is mounted, a through hole is drilled hole 14, the supply of which is carried out by the "brook" type. To the base plate 12, which is both the "frame" and the cover of the drainage tank, a discharge pressure chamber 10 is attached, designed to drain the liquid to the consumer. A pump 11 is connected to the discharge pressure chamber 10, which consists of a housing, inside of which there are sections, which in turn consist of guide devices, where the impellers are located, assembled on the shaft, the rotation of the shaft is transmitted from the electric motor by means of coupling halves.

The pump unit operates as follows.

When the drainage tank level sensor is triggered by the “upper liquid level” signal, the motor 1 is turned on, which, through the coupling 3, transmits torque via the shaft 7 to the pump part 11, which in turn drives the impellers of the pump sections, due to what happens is the suction of the liquid in the tank, and its injection into the discharge pressure chamber 10, after which the liquid passes through the check valve and enters the pipeline with a back pressure, limited by choice m size of the pumping part. When the sensor signal of the drainage tank “lower level” is triggered, the motor stops and the check valve “closes”.

Claims (2)

1. An electric centrifugal semi-submersible pump unit, consisting of an electric motor and a pump part, inside of which there are sections, which in turn consist of guide devices, where the impellers are located, assembled on a shaft, characterized by the presence of a folding chamber with an stuffing box, a base plate with mounted on her main basket with bearing and stuffing box assemblies and a coupling basket with coupling joints of the motor shaft and pump located inside. 2. An electric centrifugal semi-submersible pump unit according to claim 1, characterized in that there is a through hole in the base plate.

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