RU2643881C1 - Piston pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: piston pump contains a housing with suction and pressure valves. Two double-sided pistons are mounted inside the housing with the possibility of rotation and with the possibility of mutual, relative along the axis of the movement housing. The pistons are connected to each other and to the housing by a screw drive. The screw drive is formed and is an installed, rotatable, in the housing, a leading link-screw with an inclination angle α₁ of a screw line. The leading link-screw is connected by the formation of a screw kinematic pair with the driven link - a double-sided piston, by means of a screw-threaded hole with an angle of inclination α₁ of the screw line made at the center of its bottom. In the center of its opposite bottom the double-sided piston, in addition to the screw thread with the angle of inclination α₁ of the screw line, has a hole with a screw thread with an angle of inclination α₂ of the screw line to which it is connected, by the formation a screw kinematic pair, with an output link-screw. The output link-screw has, in addition to the screw thread with the angle of inclination α₂ of the screw line, a screw thread with an angle of inclination α₃ of the screw line, by means of which it is connected, by the formation of a screw kinematic pair, to the housing. At the free end of the output link-screw, another double-sided piston is installed. All screw threads are of one direction. For screw lines, the slope angles are: α₃<α_1<α_2. The screw drive provides the ability to convert the unidirectional rotational motion of the drive shaft into a reciprocating motion of double-sided pistons in a single housing.

EFFECT: possibility of an even distribution of the pumped liquid or gas.

9 cl, 6 dwg

Description

The invention is a volumetric type pump designed for pumping liquid bodies with the possibility of placement in wells. It can be used in pumping units.

The invention can be used in all industries, including:

in oil production during drilling, operation, well repair, to increase oil recovery;

in the chemical and petrochemical industries for pumping acids, ammonia, urea, melamine, and supplying reagents under pressure;

in the energy sector as a feed pump for a boiler plant of a steam generator;

in the food industry as a part of equipment for homogenization;

in mechanical engineering, for hydraulic presses;

in industries requiring high pressures, including explosion and fire hazard;

in public utilities during repair, pressure testing of hydraulic systems and pipelines, during washing of the sewage system;

in steam field installations as a feed pump;

in the gas industry;

in agriculture.

In addition, the device can be mounted on special equipment, and can also be used on ships and boats of all classes as bilge, cleanup and other pumps.

Known reciprocating piston pumps - rocking machine. [Oilfield equipment. TsentrLitNefteGaz 2006]

Known reciprocating steam pumps [http://dic.academic.ru/dic.nsf/bse/118688/]. Their disadvantages are the need for generating and supplying steam to the pump, as well as the need for disposal of exhaust steam, which significantly reduces the efficiency. devices.

Known (RU 2133875, published: 07.27.1999) a borehole sucker-rod pump drive containing an electric motor, kinematically coupled two-way screw with a nut, rollers with a traction element, characterized in that the nut is mounted with the possibility of axial movement along a vertical guide, directly connected to rod string from below and from above - tubing string made in the form of a flexible connection; in addition, it is equipped with a balancing counterweight placed on a rack located coaxially with the that, with the rack height is greater than the length of the nut turn.

The disadvantages of the device are: design complexity; the need for vertical placement of at least the drive part of the device, as well as the possibility of its placement only outside the well; low productivity.

Piston pumps, as well as other volumetric pumps, are characterized by supply and pressure pulsations, which is a drawback. To reduce ripple, several pistons are arranged in a row, connected to one shaft, and the operation cycles should be shifted relative to each other in phase by equal angles. This design increases the transverse dimensions of the pump.

To reduce ripple, a differential pump switching circuit is also used. Here, due to the interconnection of the main working and rod cavities, fluid injection occurs both during the forward stroke of the piston and during the reverse stroke. But such pumps do not have their own valve distribution system.

The double-sided pump has its own valve distribution system. Such pumps, unlike single-acting pumps, have a lower ripple coefficient, and the efficiency higher.

The problem to which the claimed invention is directed is to create a piston pump that provides high technical indicators (pressure, flow) with a low ripple coefficient, having insignificant transverse dimensions, capable of functioning together with any engine that allows to obtain torque from the shaft, respectively, having more high efficiency and autonomy.

The problem is solved through the use of a screw (drive) mechanism in the design of a piston pump, which provides the possibility of converting the unidirectional rotational movement of the drive shaft into reciprocating motion of the two-sided pistons in a single housing, as well as a valve distribution system that enables the uniform distribution of the pumped liquid or gas. Such a possibility is achieved by the screw mechanism due to the use of the jamming effect in various single-moving screw structural groups during rotation of the driving link - the screw.

The objective is achieved by the fact that according to the invention, the piston pump comprises a housing with suction and pressure valves, inside of which, with the possibility of rotation and with the possibility of mutual, relative along the axis of the housing movement, two double-sided pistons are installed, connected to each other and the housing by a screw drive, formed and representing an installed , with the possibility of rotational motion, in the housing, a leading link-screw having an inclination angle α _{1 of a} helix connected by the formation of a helical kinematic pair with yedoma link - two-sided piston through a hole with a screw thread with an angle of inclination α ₁ helix, taken along the center of its bottom, while the two-way piston, apart screw thread with an angle of inclination α ₁ helix, the keeper its opposite bottom has an opening with screw thread with an angle of inclination α helix _2, which it is connected form a kinematic screw pair, with the output member, the screw, at the free end of which is mounted the other two-way piston-screw output link has kro e screw thread with an angle of inclination α ₂ helix screw thread with an angle of inclination α ₃ helix, through which it is connected form a helical kinematic pair, with a housing, with all screw threads in one direction, for screw lines inclination angles: α ₃ < α ₁ <α _2. , and the linear dimensions of the screw threads are interdependent on the movements of the links.

To reduce friction, increase efficiency the screw mechanism may be a ball screw or roller screw.

To support and fix the screw drive in the drive shaft housing, as well as to provide rotation with the least resistance, and to absorb radial and axial loads, the drive shaft of the screw drive can be equipped with an angular contact bearing.

The piston pump housing may be cylindrical.

In the housing of the piston pump can be made channels for cooling, lubricating, other liquids.

The material for the manufacture of the piston pump housing may be steel.

Material for the manufacture of double-sided pistons can be bronze.

Double-sided pistons can be equipped with radial seals.

In FIG. 1, FIG. 2 schematically shows a piston pump as a part of a pumping unit. The pump unit contains a kinematically connected engine 1 and a piston pump through its screw drive. Engine 1 and a piston pump with a screw drive can be installed in one (common) housing or on a common frame. It is possible to implement a pumping unit in which the engine and the piston pump with a screw drive are each installed in their own housing. For example, a piston pump with a screw drive can be installed in one housing, and the engine is installed in another (own) housing or on a separate frame. It is possible to use a piston pump without using an engine. In this case, muscular force is used to drive the screw drive, respectively the pistons.

The housing 3 of the pump can be cylindrical and can be made detachable in various ways. For example, both end caps can be removable or one of them, the housing can be disconnected in any plane. Any engine can be used with a piston pump, the design of which provides the ability to remove torque from the shaft. This may be an electric motor, an engine operating by means of a liquid or gas, an internal combustion engine, etc. Depending on the design, the engine 1 may be provided with a hydraulic protection, other protection, or the protection of the engine may not be necessary. According to the degree of explosion protection of electrical equipment, an electric motor in general industrial design or an electric motor in explosion-proof design can be used.

The piston pump comprises a drive part and a hydraulic part. The drive part contains a screw drive (mechanism) for converting the rotational movement of the shaft into reciprocating motion of the pistons. The hydraulic part contains a cylinder (a cylindrical groove is made in the housing 3), double-sided pistons, suction and discharge valves, may contain piston seals, safety valves.

In case of use in the pump unit

A screw 2 of a screw drive (mechanism) is connected to the shaft of the engine 1, the output part, which functions as an input shaft. Accordingly, screw 2 is leading in the screw drive. Coaxial and non-coaxial connection of the motor shaft 1 with screw 2 is possible. For transmission of torque from the engine, a cardan drive, an equal-velocity joint, gear clutch, and belt drive can be used. To increase the service life, the gear used can be sealed. To compensate for dynamic loads, the connection "motor shaft 1 - screw 2" can be equipped with a flexible or elastic coupling, for example, sleeve-finger. Flexible couplings can be used on the pump side with protection, on the motor side with protection. It is also possible to connect the motor shaft with screw 2 through the gearbox, through the gearbox with a heated housing. The end cover (or partition, if the engine and the piston pump are in a single housing) of the housing 3 performs the function of supporting the output of the screw 2. To support and fix the output of the screw 2 in the housing 3, as well as to ensure rotation with the least resistance, perception of radial and axial loads, an angular contact bearing may be used. To protect the bearing, to prevent leakage of liquid, gas, vapors, seals can be installed on the output part, which functions as a shaft, on both sides of the bearing: mechanical; with manual adjustment; with spring pressure; stuffing box; cuffed; with a lock chamber and leak indicators.

In ground piston pumps, lip seals can be added to the mechanical seal to prevent fluid leakage into the atmosphere. Also, leakage can be directed to the suction line of the pump. In this case, the liquid, which in small amounts seeps through the mechanical seal, serves as a lubricant and cools the friction parts of the seal; accordingly, it is not necessary to additionally supply oil to the seal.

A screw 5, rotatably mounted in the housing 3, is connected to the screw 2, its first screw thread 4 (with an angle of inclination α _{1 of the} helix) in the hole made in the center of the bottom. The piston 5 has two bottoms (i.e. it is double-sided) ), in the center of each of which there is a threaded hole. The piston 5, by its second screw thread (with an angle of inclination α _{2 of the} helix) in the hole made in the center of the opposite bottom, is connected to the screw 7, which has two screw threads, one of which with the angle of inclination α _{2 of the} helix, the other α ₃ lines. Thus, the piston 5 can be represented as a “nut” with two different screw threads. The piston 5 and the screw 7 form a helical kinematic pair by screw thread 6 (with an angle of inclination α _{2 of the} helix). Screw 7 and housing 3 (the internal partition in the housing, which is the support of screw 7, has a threaded hole in the center, with an angle of inclination α _{3 of the} helix) form a kinematic screw pair by screw thread 8. All screw threads are the same direction, for helical lines, the angles of inclination α ₃ <α ₁ <α ₂ , and the linear dimensions of the screw threads are interdependent on the movements of the links.

A piston 9 is mounted on the free end of the screw 7 with the possibility of rotation relative to the housing 3. The piston 9 is bilateral and connected to the screw 7 pivotally or rigidly. In the case of a swivel, the screw 7 can rotate relative to the piston 9. In the case of a rigid connection, the screw 7 rotates along with the piston 9.

To prevent (reduce) leakage of gas, liquid between the pistons and the cylinder in the grooves (grooves) made on the cylindrical part of the pistons 5 and 9, radial seals can be installed. The pistons 5 and 9 in the housing 3 form three chambers “A”, “B”, “C”, which can be connected by a pressure line 10. The chambers can communicate with the space outside the housing through the suction valves 11, 12, 13. Valves 11 , 12, 13 operate by vacuum in the chambers "A", "B", "C". Also, these valves can be equipped with filters and connected by a suction line to the filter at the inlet. The valves 14, 15, 16 operate by means of pressure in the chambers "A", "B", "C", i.e. are pressure head, and provide the possibility of communication between the chambers and the pressure line 10. To reduce the radial dimensions of the device, the cross-sections of the lines can be made segmented. Suction and discharge nozzles, single, twin, etc., made of carbon steel, non-ferrous metals, their alloys, plastic, can be used. Valves 14, 15 can be located in the cylinder in such a way (Fig. 2) that at the moment the links are closed, the pistons overlap these valves. This creates a closed damping volume, which helps to reduce dynamic loads. The sequence of movement of the pistons, resulting in a change in the volume of the chambers "A", "B", "C", is determined by the kinematics of the screw pairs to which the pistons are connected. To eliminate sliding friction in a screw mechanism (helical gear), the latter can be implemented as ball screw or roller screw.

The piston pump may be equipped with a safety valve, for example, a spring valve. In normal operation, it can be adjusted to both nominal and other operating pressures. Depending on the design, the piston pump can be without a water seal or with a water seal.

Depending on the application, the piston pump can be equipped with heating or cooling. For this, the hydraulic part in design can be:

without cooling (heating) the hydraulic part with the supply to the cylinder (to its outer surface) of cooling, flushing or hydrolock fluid;

with cooling (heating) of the hydraulic part, with the supply to the cylinder (to its outer surface) of flushing, cooling or hydrolock fluid through channels made in the pump casing.

Material design of the pump

The materials used for the manufacture of the hydraulic part of the piston pump have the following requirements: high mechanical strength; low coefficient of linear expansion; high corrosion resistance; good anti-friction properties.

For the manufacture of sliding pairs (cylinder, pistons), it is possible to use steel, cast iron, bronze, alloys, and in various combinations, one part can be made of steel or cast iron, and a pair of it can be made of bronze, and vice versa.

Materials for cylinder and pistons:

chrome steel type 20X13 or 40X13 GOST 5632-72; GOST 5632-72 type 12X18H10T chromium-nickel steels; gray cast iron SCH 20, SCH 15; antifriction cast iron АЧК-2, АЧВ-2; forged carbon steels; duplex stainless steels; nickel-aluminum-bronze alloy;

bronzes: Br OF10-1, Br OTsS 6-6-3, Br AZh 9-4, etc., gray cast iron SCh 20, SCh 15, antifriction cast iron AChK-2, AChV-2.

Pistons may have a tungsten carbide coating; pistons for water are 45Ni60 surfaced. Pistons can be made of ceramic or coated with ceramic.

Valves

Conical. Each of them can be made with a guide and loaded with a spring. By design, the suction valve and the discharge valve can be identical, which facilitates maintenance.

Valve and seat materials: stainless steel, e.g. 316 steel.

Stainless steel ball valves can be used for metering pumps.

Piston seal in cylinder

Due to the placement of the pistons and their drive in a single (common to them) cylinder, the piston pump is able to function without any additional sealing elements between the pistons and the cylinder.

To prevent (reduce) leakage of gas and liquid between the pistons and the cylinder, the pistons can be made with radial grooves (grooves, protrusions) and equipped with radial seals.

Materials and types of seals:

fluorine rubber (FKM);

NBR (nitrile butadiene rubber);

self-tightening piston seal double stuffing box with soft seal back leak on suction side material: PTFE; FPM

A screw drive (mechanism) converts the rotational motion of the motor shaft into the translational motion of the pistons. The screw drive (screw mechanism) of the piston pump allows the rotation of screws 2 and 7 in any direction. Depending on the version, a thread can be used for a screw mechanism (screw-nut transmission): trapezoidal (with reverse load), persistent (with non-reverse load), and also rectangular, triangular, round, semicircular, arched. Also, depending on the design, the thread can be right, left, single and multi-start, non-self-braking.

Screws 2, 7 can be made integral, or each of them can be made integral, for example, by screwing. The screws can be made of steel 45, 50, U10, 40X, 40HG, 40HGV, A40G, 65G, etc., followed by hardening to hardness HRC 50-55 and grinding of the working surfaces.

Each "nut" can be made in the form of a bronze sleeve one-piece or detachable. Two bushings are installed in the body of the piston 5, and one in the partition in the housing 3 (the partition can also be detachable).

The bushings can be pressed in or mounted with the possibility of relatively quick removal. In the latter case, the bushings can be fixed in the body of the piston and in the baffle of the housing using clamping screws or pins. Detachable "nuts" - bushings, a split partition provide the ability to disassemble (assembly) faster.

Material of the “nut”: bronzes Br ОФ10-1, Br ОЦС 6-6-3, Бр АЖ 9-4, etc., gray cast iron СЧ 20, СЧ 15, antifriction cast iron АЧК-2, АЧВ-2.

Also, the pistons themselves, end caps, partitions in the housing 3 can be made of these materials and without any bushings.

It is possible to perform a screw mechanism with a ball screw. In this case, the rolling screw-nut transmission is formed by balls placed between the screw surfaces of the screw and nut. When the screw rotates in one direction, the balls roll over and through the bypass channel in the nut (bypass channels can be made in the piston body and in the baffle) are returned to the working area.

Such a helical pair is not self-braking and can be used both to convert rotational motion to translational, and vice versa. In addition, such a transmission is characterized by high rigidity and accuracy, the possibility of a complete selection of the gap, the ability to work without lubrication, low wear rate, high KPD The material of the screw can be steel 8XF, nuts - steel 9XC, heat treatment - surface hardening to hardness HRC 58-62.

Screw Drive Function

The screw drive of the piston pump is a mechanism for converting rotational motion into reciprocating, that is, a screw mechanism, schematically shown in FIG. 3, FIG. 4, FIG. 5, FIG. 6, where its functioning is represented by several kinematic combinations of mobile links.

Such a screw mechanism comprises a leading link-screw 2 mounted rotatably in a support (in the “left” end cover of the housing 3). Screw 2 forms a support kinematic rotational pair (VR. KP _3-2 ),

α ₁ - the angle of inclination of the helix of the screw 2.

An output link - a differential nut (piston 5), having (th) two screw threads, is connected to the lead screw screw 2 by means of a screw thread with an inclination angle α _{1 of the} helix line, where:

α ₁ - the angle of inclination of the helix of the nut (helical thread of the piston 5, the "left"part);

α ₂ - the angle of inclination of the helix of the nut (screw thread of the piston 5, the "right" part).

A nut (piston 5) by means of a screw thread with an angle of inclination α ₂ , a helical line is connected to the output link-screw 7, which has two screw threads, one of which with an angle of inclination α _{2 of the} helix, the other - α _{3 of the} helix.

Thus, the nut (piston 5) forms the first helical kinematic pair (VKP _2-5 ) with the leading screw-link 2 and the second helical kinematic pair (VKP _5-7 ) with the output screw-link 7.

The screw 7 through its second screw thread with an angle of inclination α _{3 of the} helix is connected to a support (with an internal partition in the housing, which is the support of the screw 7) having a screw thread with an angle of inclination α _{3 of the} helix, forming a third kinematic screw pair (VKP _{7- 3} ).

All screw cuts in one direction, while the angles of inclination of the helix lines:

α ₃ <α ₁ <α _{2 ,.} The linear dimensions of the screw threads are interdependent on the movements of the links.

Kinematic screw pairs can form various combinations between themselves, which allows one-way rotation of the leading screw-link 2 to provide reciprocating movements of the output links - the nut (piston 5) and screw 7. Providing the ability to convert the unidirectional rotational movement of the driving link into reciprocating the movement of the output links is decided by obtaining the ability to transform the mechanism structurally, when using the jamming effect, when the driving link-screw is rotated, into various single-movable screw structural groups.

When the screw 2 is rotated, the piston 5 moves from the extreme position by the stroke of the screw 2 in the direction of decreasing the volume of chamber “A”. Due to this, the working fluid is pumped through valve 14 into the line 10. The piston 5, by its screw thread 6, drives the screw 7 with the piston 9. In this case, the volumes of the chambers “B” and “C” increase. With an increase in the volume of the chamber "B", the process of suction of the working fluid into this chamber through the valve 12. There is a process of suction of the working fluid into this chamber through the valve 13.

The piston 5 closes with the screw 2, thereby forming a rotational link (screw - piston). The rotation of the piston 5 is converted into the translational components of the screw 7 with the piston 9, the chamber "C" increases, respectively, the suction occurs, the chamber "B" decreases, respectively, the injection occurs. The volume of chamber “A” will not change.

At the end of the stroke of the screw 7, the piston 5 and the screw 7 will be closed to each other and together with the piston 9 will receive the translational component of the movement, as a result of which the volume of the chamber "A" will increase, accordingly, the process of absorption into this chamber, the volume of the chamber "C" will decrease, respectively, there will be a pumping process from this chamber. The volume of chamber "B" will remain unchanged.

Moving the piston 5 and the screw 7 will lead to the closure of the screw 7 on the housing 3. Screw 7, having closed on the housing 3, becomes a rack. With the rotation of the screw 2, the translational component of the screw movement of the piston 5 will lead to an increase in the volume of the chamber "B" and a decrease in the volume of the chamber "A". The volume of the camera "C" will not change. Further cycles are repeated.

Claims (9)

1. A piston pump, characterized in that it contains a housing with suction and pressure valves, inside of which, with the possibility of rotation and with the possibility of mutual, relative along the axis of the housing movement, two double-sided pistons are installed, interconnected with the housing by a screw drive, formed and representing an installed with the possibility of rotary motion in the housing, the screw-driving member having an inclination angle α ₁ helix, linked, form a kinematic screw pair, with the driven member - bi side of the piston through the hole with screw thread with an angle of inclination α ₁ helix, taken along the center of its bottom, while the two-way piston, apart screw thread with an angle of inclination α ₁ helix, the keeper its opposite bottom has an opening with a screw thread with angle α helix _2, which it is bound, form a kinematic screw pair, with the output member, the screw, at the free end of which is mounted the other two-way piston-screw output member has, in addition screwthreaded with an angle of inclination α ₂ helix screw thread with an angle of inclination α ₃ helix, through which it is bound, form a helical kinematic pair, with a housing, with all screw threads in one direction, for screw lines inclination angles: α ₃ <α ₁ <α _2. , and the linear dimensions of the screw threads are interdependent on the movements of the links. 2. The piston pump according to claim 1, characterized in that the screw drive is made of ball screw. 3. The piston pump according to claim 1, characterized in that the angular contact bearing provides support and fixation of the drive shaft of the screw drive. 4. The piston pump according to claim 1, characterized in that the housing is cylindrical. 5. The piston pump according to claim 1, characterized in that the channels for liquid are made in the housing. 6. The piston pump according to claim 1, characterized in that the housing is made of steel. 7. The piston pump according to claim 1, characterized in that the double-sided pistons are made of bronze. 8. The piston pump according to claim 1, characterized in that the double-sided pistons are equipped with radial seals. 9. The piston pump according to claim 8, characterized in that the radial seals are made of elastic material.

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