This application is the U.S. national phase of International Application No. PCT/RU2019/000700 filed Oct. 2, 2019, which claims priority to Russian Application No. 2018134507 filed Oct. 2, 2018, the entire contents of each of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to pumping assemblies designed for pumping fluids with high content of solid particles and/or aggressive or toxic liquids and lifting them from any depths including lifting from deep boreholes.

BACKGROUND

A bellows pump with hydraulic drive for pumping water or contaminated liquids is known. Such pump consists of at least two pumping units. Each pumping unit comprises a working-fluid-controlled hydraulic cylinder as the drive coupled with a separate hydraulic cylinder for dosed working fluid injecting to or pumping out of the working-fluid-controlled hydraulic cylinder. Each working-fluid-controlled hydraulic cylinder comprises a bellows closed in its lower end part and open in its upper end part for connection with the working fluid. The bellows is placed into a chamber filled with the pumped fluid [WO2015128283, Hydraulically driven bellows pump, published Sep. 3, 2015] [1].

One of the disadvantages of this pump consists in friction arising during operation of the hydraulic cylinder in the pump discharge line. This friction causes significant power consumption during operation. Another disadvantage is in possible leaking through seals on the piston, which separates the working fluid inside the diaphragm from that in the discharge line. Besides, installation of any additional equipment increases its overall dimensions. The working-fluid-controlled hydraulic cylinder has a hole in its lower part operating as the pumped fluid inlet/outlet port. However, such arrangement of the inlet/outlet port may cause contamination of internal chamber inside the working-fluid-controlled cylinder and/or formation of air bubbles in upper part of the cylinder.

The present technical solution differs from above described prior art in the following design features:

Working fluid is injected by a force pump directly into internal chamber of the rolling diaphragm (bellows) inside the discharge line. Therefore, there is no friction pairs.

Working fluid is pumped off the internal chamber of the bellows inside the discharge line by a special draw-off pump.

Pumping assembly housing has few inlet/outlet ports, wherein the inlet port is located in lower part of housing while the outlet port is located in the upper part of housing.

A GEHO® APEXS type pump of Weir Minerals Netherlands is also known.

This pump is a double-chamber single-acting high-pressure hose plant with hydraulic drive designed for pumping any contaminated liquids. The plant has a rigid housing and a flexible tubular assembly inside the housing. This assembly comprises at least two working-fluid-controlled hydraulic cylinders. Each working-fluid-controlled hydraulic cylinder comprises a deformable member in the form of an elastic pipe closed in its upper end part and open in its lower end part for the pumped fluid. The elastic pipe is placed into a chamber filled with the working fluid. Injecting or pumping off the working fluid to or from the chamber of working-fluid-controlled cylinder causes respective changes in working volume of the said elastic pipe. Consequently, operation of such pump consists in alternating injecting and pumping off the working fluid to or from the working-fluid-controlled cylinder chamber [Application WO2004011806, IPC F04B43/10; F04B43/113. Fluid operated pump/Combined Resource Engineering [AU]; Morris Gordon Leith; West Robert Leslie.—Application WP2003AU00953; filed Jul. 29, 2003; published Feb. 5, 2004].

This type of pumps suffers from the disadvantage inherent to usage of an elastic pipe as the working body to provide changes in working volume. Namely, the elastic pipe is stretched during operation, which leads to faster wear of the working body. Besides, the working-fluid-controlled cylinders must be inclined at an angle to horizon. However, inclined position can cause clogging (deposition of mechanical impurities) since the working-fluid-controlled hydraulic cylinder has a single hole in its lower part operating as the pumped fluid inlet/outlet port, while application of the elastic tubular diaphragm requires a complex system to monitor and control the working position of the diaphragm in extended or compressed state. Moreover, deformation of the elastic tubular diaphragm must obey a well-known law in order that such system was operable.

SUMMARY OF THE INVENTION

The aim of this invention is to present a high-performance pumping assembly.

The technical results of this invention consist in reducing weight and overall dimensions of the pump assembly as well as increasing energy efficiency and reliability. The first said result is achieved by using a longitudinally stretchable bellows, which in turn allows to apply a lighter and more compact cylindrical pump housing with the cylinder length-to-diameter ratio of 2 to 1 or more, whereas larger working volume of the bellows per stroke allows to reduce the number of cycles at the same productivity and thereby increase the life of bellows.

A direct hydraulic drive, designed as a system of hydraulic valves and hydraulic pumps that alternately connects hydraulic lines to internal chamber of the bellows, has no friction pairs inherent to other types of bellows pumps, in particular, piston or plunger pumps, and hence is friction-free and maintenance-free. At the same time, all hydraulic drives are several times smaller in size and weight compared to piston or plunger drives equipped with cumbersome and heavy crank gears at the same rated capacities.

Another result of the invention is achieved by improving energy efficiency due to combining the bellows and the direct hydraulic drive with at least two independent hydraulic lines such that at least one line is under working fluid pressure below the pumped fluid inlet pressure, and at least one line is under working fluid pressure higher than the pumped fluid inlet pressure.

Yet another result of the invention is achieved due to the fact that the pumping assembly comprises a housing consisting of at least two parts with internal cylindrical chambers and having holes for supplying and discharging the pumped fluid; two or more longitudinally stretchable bellows attached with one end surface to each part of the housing from inside, the opposite end side of each bellows being closed with a plug, while the end surface of each part of housing connected with the bellows having a hole for supplying the working fluid to the internal chamber bounded by the bellows, its plug, and the end surface of the part of the housing; and a pumping assembly hydraulic control system, wherein the pumping assembly hydraulic control system comprises a tank containing the working fluid; a force pump; two or more independent hydraulic lines, and a valve system capable to alternately connect internal chambers of bellows to the first or second line depending on positions of the bellows, the hydraulic lines being designed in such a way that the first line is under working fluid pressure below the pumped fluid inlet pressure and the second line is under working fluid pressure higher than the pumped fluid inlet pressure; internal chamber of each bellows is connected to the said lines with the possibility of alternatively switching between the force pump for supplying the working fluid via the first hydraulic line and the tank containing the working fluid via the second hydraulic line, and the pumping assembly further comprises means for tracing position of each bellows being configured to control alternate connection of internal chamber of each bellows to the first or second line depending on the bellows position.

In one particular embodiment of the present invention, means for tracing position of each bellows are installed in internal chamber of this bellows and comprise a fixed tube and rod, one end of the rod being attached to the bellows plug and the other end being loosely inserted in the tube attached to the surface opposite to the bellows plug. Rod position transducers are installed on the tube at a distance of bellows stroke.

In one particular embodiment of the present invention, a pump is additionally installed on the second hydraulic line for pumping the working fluid into the tank.

In one particular embodiment of the present invention, means for tracing position of each bellows are installed in internal chamber of this bellows and comprise position transducer, rod and tube, one end of the rod being attached to the bellows plug and the other end being loosely inserted in the tube attached to the surface opposite to the bellows plug. The rod has marks (e.g., 200a-200n) to control the rod position.

In one particular embodiment of the present invention, means for tracing position of each bellows are installed in internal chamber of this bellows and comprise position transducer, revolvable spool, and a cable wound around the spool, the spool being attached to the surface opposite to the bellows plug, while the wound cable having one end fixed on the plug.

In one particular embodiment of the present invention, means for tracing position of each bellows comprise a rotation speed sensor mounted on the force pump and designed to monitor filling of internal chamber of the bellows by determining the working fluid volume necessary to fill the internal chamber of the bellows.

In one particular embodiment of the present invention, holes for supplying and discharging the pumped fluid are made in the lower and/or upper part of pump housing.

In one particular embodiment of the present invention, a bellows is made composite of individual elastic membranes connected in series with each other by end surfaces.

