CN219242329U

CN219242329U - Closed hydraulic system of double-pump hydraulic pumping unit

Info

Publication number: CN219242329U
Application number: CN202320834454.3U
Authority: CN
Inventors: 耿路; 耿护厂
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2023-06-23
Anticipated expiration: 2033-04-14

Abstract

The utility model relates to the technical field of hydraulic pumping units used for oil extraction in oil fields, in particular to a closed hydraulic system of a double-pump hydraulic pumping unit, which comprises a bidirectional oil pump I and a variable frequency motor I, wherein the bidirectional oil pump I is connected with the variable frequency motor I, the bidirectional oil pump I is connected with oil ways on two sides of the bidirectional oil pump I, the closed hydraulic system also comprises a bidirectional oil pump II and a variable frequency motor II, the bidirectional oil pump II is connected with the variable frequency motor II, and the bidirectional oil pump II is connected with the oil ways on two sides. The utility model adopts the form of a double-pump self-priming automatic oil-supplementing closed hydraulic system to be applied to double-well self-balancing occasions, can replace a large-displacement oil pump by utilizing a small-displacement oil pump, reduces the power of the whole machine, and realizes energy conservation and consumption reduction.

Description

Closed hydraulic system of double-pump hydraulic pumping unit

Technical Field

The utility model relates to the technical field of hydraulic pumping units used for oil extraction in oil fields, in particular to a closed hydraulic system of a double-pump hydraulic pumping unit.

Background

The existing hydraulic pumping unit hydraulic system for oil extraction in the oil field is generally a single-pump hydraulic system, when the single-pump closed hydraulic system is applied to replace an old mechanical beam pumping unit (a kowtow machine), a large-displacement oil pump (more than 160 ml/rpm) is required to be used in a higher stroke occasion (more than 4 strokes/min), meanwhile, the power of a matched motor is not less than 30kw, the power load of a matched power supply cable of the existing oil field is often exceeded, and the oil field is required to be additionally replaced to provide the cable for use, so that the cost is increased.

The prior patent CN114370438A discloses an automatic oil supplementing closed hydraulic system of a hydraulic pumping unit, which comprises a variable frequency motor, a bidirectional hydraulic motor, a one-way valve, an electric control one-way valve, an electromagnetic overflow valve, a displacement sensor and an oil cylinder, wherein the connection relation of a main oil way is as follows: the variable frequency motor is connected with the two-way hydraulic motor, the two-way hydraulic motor is connected with the oil cylinders on two sides through the oil pipe of the main oil way, the displacement sensor is arranged in the oil cylinders, one end of the electromagnetic overflow valve is connected with the main oil way through the oil pipe, the other end of the electromagnetic overflow valve is connected with the oil tank through the oil pipe, and the oil supplementing oil way is connected with the oil tank through the oil pipe at one end of the two-side one-way valve, and the other end of the oil supplementing oil way is connected with the main oil way through the oil pipe of the electric control one-way valve. When the single-pump closed hydraulic system is applied to replace an old mechanical beam pumping unit (a kowtow machine), a large-displacement oil pump (more than 160 ml/rpm) is needed to be selected in a higher stroke occasion (more than 4 stroke/min), meanwhile, the power of a matched motor is not less than 30KW, the power load of a matched power supply cable of an existing oil well is often exceeded, the power supply cable is needed to be additionally replaced by the oil field for use, the replacement cost is increased, meanwhile, the quality of the existing large-displacement oil pump product is generally not excessively closed, the problems of large leakage amount, low efficiency, short service life and the like are solved, the production efficiency is easily reduced, and the operation cost is increased.

Disclosure of Invention

The embodiment of the utility model provides a closed hydraulic system of a double-pump hydraulic pumping unit, which aims to solve the problems of large oil pump discharge capacity, large power of an electric motor of an oil pump, high cable cost and the like required by the existing single-pump closed hydraulic system.

The utility model adopts the following technical scheme:

the closed hydraulic system of the double-pump hydraulic pumping unit comprises a two-way oil pump I and a variable frequency motor I, wherein the two-way oil pump I is connected with the variable frequency motor I, the two-way oil pump I is connected with oil ways on two sides of the two-way oil pump I, each oil way respectively comprises an oil cylinder, an overflow valve and a directional logic valve I, each oil cylinder is respectively connected with the directional logic valve I and the overflow valve through an oil pipe, the directional logic valve I is connected with the two-way oil pump I through an oil pipe, the two-way oil pump II is connected with the variable frequency motor II, and the two-way oil pump II is connected with the oil ways on two sides.

Compared with the prior art, the utility model has the beneficial effects that:

the two oil pumps with the same size can participate in normal operation at the same time, one oil pump can supplement oil for the other oil pump, and under the condition of requiring the highest working pressure output of the same system, the sum of the power of motors matched with the two single pumps is smaller than that of the motors matched with the existing single pump system, so that the power of the whole machine is greatly reduced, and meanwhile, the cost of a cable is also reduced.

Further, the utility model adopts the preferable scheme that:

two sides of the two-way oil pump II are respectively connected with inlets of the two-side oil ways of the two-way logic valve I through the two-way logic valve II, and two sides of the two-way oil pump II are respectively connected with the oil tank through the oil supplementing one-way valve.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this application, illustrate and together with the description serve to explain the utility model. In the drawings:

FIG. 1 is a schematic diagram of the structure of the present utility model;

FIG. 2 is a schematic diagram of a prior art single pump closed hydraulic system;

in the figure: a lifting cylinder 1; a lowering cylinder 2; a well rod 3; an overflow valve 4; a directional logic valve I5; a directional logic valve II 6; an oil supplementing one-way valve 7; an oil suction filter 8; an oil tank 9; a two-way oil pump I10; a variable frequency motor I11; a two-way oil pump II 12; and a variable frequency motor II 13.

Detailed Description

The present utility model will be described in further detail with reference to the following embodiments and the accompanying drawings, in order to make the objects, technical solutions and advantages of the present utility model more apparent. The exemplary embodiments of the present utility model and the descriptions thereof are used herein to explain the present utility model, but are not intended to limit the utility model.

As shown in fig. 1, a closed hydraulic system of a double-pump hydraulic pumping unit mainly comprises a two-way oil pump 10, a variable frequency motor 11 and the like, wherein the two-way oil pump 10 is connected with the variable frequency motor 11, the two-way oil pump 10 is respectively connected with oil ways on two sides, each oil way is respectively composed of an oil cylinder, an overflow valve 4, a directional logic valve 5 and the like, and each oil cylinder is respectively connected with the directional logic valve 5 and the overflow valve 4 through oil pipes.

In this embodiment, a second bidirectional oil pump 12 and a second variable frequency motor 13 are further provided, the second variable frequency motor 13 is connected with the second bidirectional oil pump 12, and two sides of the second bidirectional oil pump 12 (i.e. one side of an oil outlet and one side of an oil inlet of the second bidirectional oil pump 12) are correspondingly connected with oil paths on two sides through a second directional logic valve 6 respectively.

Two sides of the two-way oil pump II 12 in the embodiment are also respectively connected with oil supplementing one-way valves 7, and each oil supplementing one-way valve 7 is respectively connected with a corresponding oil tank 9 through an oil absorbing filter 8.

In this embodiment, two oil wells with the same load ports are respectively provided with an oil cylinder to drive the corresponding well rod 3 to reciprocate up and down, and the oil paths of the two oil cylinders are respectively connected with the two-way oil pump I and the two-way oil pump 10 and the two-way oil pump 12 to form a closed hydraulic circuit.

As shown in fig. 1, for convenience of description, the two cylinders are divided into a lift cylinder 1 and a drop cylinder 2, and the displacement relationship of the lift cylinder 1 and the drop cylinder 2 may be interchanged.

Lifting oil cylinder 1 during normal operation, lowering oil cylinder 2 can descend by the dead weight of well rod 3, meanwhile directional logic valve one 5 and directional logic valve two 6 are opened completely, oil in lowering oil cylinder 2 is pressed into lifting oil cylinder 1 by two bidirectional oil pumps, well rod 3 potential energy corresponding to lowering oil cylinder 2 is fully recycled by self-balancing of double well load so as to achieve the purpose of energy saving, and because the load of two wells is basically self-balanced, the pressure difference between oil inlets and oil outlets of two bidirectional oil pumps is lower during normal operation, and therefore the input power of a frequency conversion motor actually needed is also lower.

If the oil of the closed system circuit is lost due to leakage of the bidirectional oil pump, when the descending oil cylinder 2 reaches the bottom dead center, the first directional logic valve 5 positioned on one side of the descending oil cylinder 2 is closed to stop the descending oil cylinder 2, and at the moment, the ascending oil cylinder 1 does not reach the top dead center due to the oil loss, and oil is needed to be replenished for the ascending oil cylinder 1 to obtain the oil to continuously ascend. When oil is replenished, the bidirectional oil pump II 12 in the embodiment stops the oil supply of the oil inlet of the reverse-rotation bidirectional oil pump I10, and simultaneously closes the directional logic valve II 6 at one side of the oil inlet of the bidirectional oil pump II 12, so that the oil can only be obtained from the oil tank 9 through the oil replenishing one-way valve 7 at one end of the oil inlet in a self-priming way, and a certain pressure is formed to be supplied to the bidirectional oil pump I10 (the bidirectional oil pump I is a forward-rotation oil pump), and the oil is supplied to the lifting oil cylinder 1 after the bidirectional oil pump I10 is subjected to the forward rotation and the secondary pressurization so as to be lifted to the top dead center. The oil supplementing operation at this time is to increase the pressure of the oil inlet of the first 10 (forward rotation oil pump) bidirectional oil pump, and the two bidirectional oil pumps can share half of the load pressure of the well rod respectively, so that the input power of a single bidirectional oil pump is greatly reduced, and the two oil wells can be normally lifted and lowered by circulating and reciprocating.

Comparing the closed hydraulic system of the double-pump oil pumping machine of the embodiment with the existing closed hydraulic system of a single pump:

the selection calculation basis of the motor and the oil pump is as follows:

system flow Q (L/min) =pump displacement Vg (ml/r) ×pump speed n (rpm) ×volumetric efficiency v/1000

Pump torque M (NM) =1.59 pump displacement Vg (ml/r) differential pressure Δp (Mpa)/(10 mechanical efficiency mh)

Power P (KW) =system flow Q (L/min) differential pressure Δp (Mpa)/(60 total efficiency t)

Wherein: volumetric efficiency v;0.92-0.98, 0.95

Mechanical efficiency mh:0.86-0.97, 0.92

Total efficiency t=volumetric efficiency v mechanical efficiency mh=0.95×0.92=0.87

According to the above formula, when:

the system flow rate Q=170L/min, the load of the two cylinders is 5 tons to form self-balance, the highest working pressure P=9 Mpa of the corresponding system, and when the pump rotating speed n=980 rpm,

the pressure difference between the inlet and outlet of the oil pump required by normal operation (without oil supplement) is about 3MPa (namely delta P=3 MPa, and only the load inertia and friction resistance are overcome).

When the oil is replenished, the balance load is lost because the descending oil cylinder 2 is stopped, so that the total pressure of the system reaches 9MPa absolute value to meet the lifting of the load of the independent ascending oil cylinder 1, the power required by the oil replenishing stage is highest, and the total pressure reaches 9MPa absolute value to calculate the power of the motor required by the oil pump. Meanwhile, since the lifting cylinder 1 is already close to the top dead center in the oil supplementing stage, the speed must be reduced (finally stopped) to ensure that the system is stable and has no impact.

For the existing single-pump closed hydraulic system, a typical schematic diagram (fig. 2) of the existing single-pump closed hydraulic system is as follows:

when the oil is replenished, the existing single-pump system oil pump must be slowed down (finally stopped) and independently output the system pressure of 9MPa, namely, independently absorb oil from the oil tank and output the oil pressure of 9MPa.

When oil is replenished, the pressure difference delta P (Mpa) of an oil inlet and an oil outlet of the pump is=the highest working pressure P=9 Mpa of the system,

the working pressure is approximately 3Mpa during normal operation (without oil supplement),

then: oil pump displacement vg=182.6 ml/r, pump torque m=284 NM, power p=29.3 KW.

A2F 200-oil pump (displacement 200 ml/r, according to the Ward bi-directional plunger pump/motor parameters) is selected.

And a YVF-225M-6/30 KW motor, rated torque 287 NM and current 62A (according to Siemens variable frequency motor parameters) are matched.

Total power = 30KW, current 62A.

For the closed hydraulic system of the double-pump hydraulic pumping unit in the embodiment:

when the oil is replenished, the two-way oil pump II 12 reversely rotates to supply oil to the two-way oil pump I10, so that the lifting speed is reduced, and meanwhile, the two oil pumps share the system pressure of 9MPa, namely, the two-way oil pump II 12 absorbs oil from the oil tank 9 and the oil outlet pressure reaches 4.5MPa, and the two-way oil pump II is supplied to the two-way oil pump I10, and the two-way oil pump I10 outputs 4.5MPa on the basis of obtaining the oil inlet pressure of 4.5MPa, so that the total system pressure of 9MPa is ensured to be output; meanwhile, the oil outlet pressure of a single bidirectional oil pump reaches 4.5MPa, and the requirement that the oil inlet and outlet pressure difference of the oil pump is about 3MPa (namely delta P=3 MPa) in normal operation is met.

The oil inlet and outlet pressure difference delta P (Mpa) =P/2=4.5 Mpa (3 Mpa higher than the working pressure in normal operation),

then: single oil pump displacement vg=91.3 ml/r, pump torque m=71 NM, power p=7.3 KW.

A2F 100-oil pump (displacement 100 ml/r, according to the Ward bi-directional plunger pump/motor parameters) is selected.

And a YVF-160M-6/7.5 KW motor, rated torque 71.6NM and current 17.2A (according to Siemens variable frequency motor parameters) are matched.

Total power = 2 x 7.5 = 15KW, current = 2 x 17.2 = 34.4A.

In summary, the single oil pump displacement required by the closed hydraulic system of the double-pump hydraulic pumping unit only needs 50% of the oil pump displacement required by the existing closed hydraulic system of the single-pump hydraulic pumping unit, the total power of the whole machine only needs 50% of the power of the existing closed hydraulic system of the single-pump, and the current only needs 55.5% of the current of the existing closed hydraulic system of the single-pump hydraulic pumping unit, so that the power is obviously reduced, and the current is reduced. The field installation and operation cost can be reduced better, and the energy saving and consumption reduction can be achieved. Meanwhile, the existing oil pump has mature product technology below 160ml/r and reliable quality, thereby being beneficial to reducing the failure rate and improving the operation efficiency.

The embodiment realizes the working requirement that the small-displacement oil pump replaces the large-displacement oil pump, so that the problem that the quality of the existing large-displacement oil pump is generally not too close is avoided and the failure rate is reduced under the condition that the total flow output requirement of the system is ensured; under the condition of the highest working pressure output of the same system, the power of the motor matched with each single pump is far smaller than that of the motor matched with the single pump system, the power of the whole machine is greatly reduced, and the purposes of energy conservation and consumption reduction are realized.

The utility model adopts a double-pump self-priming automatic oil supplementing closed hydraulic system to be applied to double-well self-balancing occasions, adopts two bidirectional oil pumps with the same size, wherein one oil pump can rotate in the same direction with the other oil pump to jointly output pressure oil to multiply the flow, can reversely rotate to supplement oil for the other oil pump, and is matched with a directional logic valve to ensure that the two oil cylinders can work identically each time, so that the forward and reverse rotation of a closed system can be realized by controlling the forward and reverse rotation of a variable frequency motor, and the opening and closing of an oil pump oil sucking pipeline can be controlled by utilizing the directional logic valve and the unidirectional oil supplementing valve 7, so that the automatic oil supplementing is realized without adding an additional oil pump, thereby simplifying the structure, reducing the heating, being beneficial to reducing the failure rate and prolonging the service life of each element. Meanwhile, the rotating speed of the variable frequency motor is controlled to steplessly adjust the lifting and descending speeds of two oil well rods so as to adapt to the changing requirements of oil pumping stroke times under different working conditions in production.

The above is only a specific embodiment of the present utility model, but the present utility model is not limited thereto, and all equivalent changes or substitutions to the technical features of the present utility model, which are conceivable to those skilled in the art, are included in the scope of the present utility model.

Claims

1. The utility model provides a two pump hydraulic pumping unit closed hydraulic system, includes two-way oil pump first and inverter motor first, two-way oil pump first is connected with the oil circuit of its both sides, and every oil circuit includes the hydro-cylinder respectively, overflow valve and directional logic valve first, and every hydro-cylinder is connected with directional logic valve first and overflow valve through oil pipe respectively, and directional logic valve first is connected with two-way oil pump through oil pipe, its characterized in that: the motor also comprises a two-way oil pump II and a variable frequency motor II, wherein the two-way oil pump II is connected with the variable frequency motor II, and the two-way oil pump II is connected with oil ways on two sides.

2. The closed hydraulic system of the double-pump hydraulic pumping unit according to claim 1, wherein: two sides of the two-way oil pump II are respectively connected with the directional logic valve I on the oil paths of the two sides through the directional logic valve II, and two sides of the two-way oil pump II are respectively connected with the oil tank through the oil supplementing one-way valve.