CN203239964U

CN203239964U - Constant pressure valve with equal displacement

Info

Publication number: CN203239964U
Application number: CN 201320160842
Authority: CN
Inventors: 秦积舜; 廉黎明; 李实�; 陈兴隆; 俞宏伟; 张可; 李军
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2013-04-02
Filing date: 2013-04-02
Publication date: 2013-10-16
Anticipated expiration: 2023-04-02

Abstract

The utility model relates to an equal displacement constant pressure valve, wherein, the valve has a valve body, a hollow part of the valve body forms a valve rod channel, a valve rod can movably penetrate through the valve rod channel, two sealing devices capable of sealing the valve rod channel are arranged on the valve rod, a sealing space is formed between the two sealing devices, and a fluid outlet can be sealed in the sealing space; two branch inlets are formed in the side wall of the valve body along the length direction of the valve rod, the branch inlets are communicated with the inlet flow channel, and the branch inlets and the fluid inlets are respectively located on two sides of the fluid outlet. In the valve rod displacement process of the valve, the fluid on one side to be compressed can be supplemented to the other side to release the space, so that the total volume of the fluid is unchanged in the space of the valve runner, the pressure of the closed system is kept constant in the valve opening and closing process, and the pressure fluctuation phenomenon of the conventional valve in the opening and closing process is eliminated; the method is suitable for the switch control of a closed system with small fluid volume.

Description

Constant pressure valve with equal displacement

Technical Field

The utility model relates to a can eliminate a displacement constant voltage valve of valve pressure oscillation phenomenon in the switching process belongs to oil gas field development experiment technical field.

Background

The valve is widely applied in various industry fields and has various types. In oil and gas field development experiments, 3mm needle valves or ball valves are largely used in low-flow experiment flows, and the device is characterized by simple control and high pressure resistance; the pressure resistance of the ball valve is less than 15MPa, and the pressure resistance of the needle valve can be not less than 100 MPa.

The pore volume of the microscopic physical model is very small and is between 0.01 mu L and 1 mL. In the microscopic physical simulation experiment, the two sides of the microscopic model are required to be provided with the switch valves to control the fluid to enter and exit, and in order to obtain the high-quality experiment effect, the smaller the fluid volume in the valve control range, the better. Typically, the volume of fluid in this range can be controlled to be within 0.2 ml. In the conventional oil and gas field development experiments such as core displacement, the volume of fluid in the model is far more than 1ml, the influence of pressure fluctuation caused by the opening and closing process of a valve on the experiment process can be completely ignored, but the influence on the micro model is not negligible. Taking the ground crude oil as an example, the compression coefficient is 4-7 x 10^-4MPa^-1When the needle point of the 3mm valve descends for 1mm, the pressure increase of about 3MPa can be caused in 0.2ml of closed fluid, and the micro model made of glass is easy to crack.

There are two methods to avoid this phenomenon: firstly, the valve is very weak in opening degree (namely, the distance for the needle point of the valve to descend when the valve is closed is very small); secondly, the volume of the closed fluid is increased. Clearly, both methods suffer from a number of disadvantages. For example, one method requires that the fluid be single phase, for example, the flow of foam will change the volume of the gas phase in the foam as it passes through, which will distort the simulation of such fluids; and the weak degree of opening of the valve is difficult to control, so that the too weak degree causes overlarge flow resistance at the needle point inlet, and the misleading of experimental operation is easy. If the second method is applied in the displacement process, the situation that the driving fluid cannot enter the observation range at a later time occurs, and if the driving fluid and the fluid in the model have interaction, the observation is delayed due to the overlong time to be observed, so that the opportunity of recognizing the experimental phenomenon is lost.

In view of the above-mentioned shortcomings of the prior art, the present invention provides an equal displacement constant pressure valve, which is developed based on the production and design experience of the present field and the related field for many years, so as to eliminate the pressure fluctuation phenomenon of the valve during the opening and closing process.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a can eliminate the pressure fluctuation's of valve switching process equipotential pressure valve.

Therefore, the utility model provides an equipotential constant pressure valve, it has a hollow valve body, the well kenozooecium of the said valve body forms the valve stem channel, a valve stem can be worn to locate in the said valve stem channel movably, the said valve stem channel is linked together with fluid inlet, fluid outlet separately, said fluid inlet and fluid outlet are linked together with the valve body outside through the inlet runner, outlet runner separately; two ends of the valve body are sealed through an upper gland and a lower gland, wherein two sealing devices capable of sealing a valve rod channel are arranged on the valve rod, a sealing area is formed between the two sealing devices, and the fluid outlet can be sealed in the sealing area; the side wall of the valve body is provided with two branch inlets along the length direction of the valve rod, the branch inlets are communicated with the inlet flow channel, and the branch inlets and the fluid inlet are respectively positioned at two sides of the fluid outlet.

The equal-displacement constant-pressure valve is characterized in that the distance between the branch inlet close to the fluid inlet and the fluid outlet is greater than or equal to the distance between the two sealing devices.

The equal-displacement constant-pressure control valve is characterized in that two grooves are formed in the valve rod, and a sealing ring is embedded in each groove to form the sealing device.

The equal-displacement constant-pressure valve as described above, wherein the distance between the two grooves is equal to or less than the distance between the branch inlet near the fluid inlet and the fluid outlet.

The equal displacement constant pressure valve is characterized in that the diameters of the fluid inlet, the fluid outlet, the branch inlet, the inlet flow channel and the outlet flow channel are 0.5mm-1.0 mm.

The equal displacement constant pressure valve as described above, wherein the width of the sealing means is smaller than the diameter of the inlet and outlet flow passages.

Compared with the prior art, the utility model has the characteristics and advantages that:

by utilizing the equal-displacement constant-pressure valve, the branch inlet communicated with the fluid inlet is arranged, so that the fluid on one side to be compressed can be supplemented to the other side release space in the movement process of the valve rod, the total volume of the fluid is unchanged in the closed space of the valve, the constant pressure in the closed system in the opening and closing process of the valve is kept, and the pressure fluctuation phenomenon of the conventional valve in the opening and closing process is eliminated; that is, the in-process of closing the valve after opening valve injection pressure and making the micro model internal pressure reach design pressure, it is undulant not to produce the pressure differential in the micro model, consequently, the utility model discloses the small closed system on-off control of specially adapted fluid volume.

Drawings

The drawings are only intended to illustrate and explain the present invention and do not limit the scope of the invention. Wherein,

fig. 1 is a schematic structural view of an equal displacement constant pressure valve of the present invention;

fig. 2 is a schematic structural view of the valve body of the constant pressure valve with equal displacement of the present invention;

fig. 3 is a schematic view of the valve stem structure of the constant pressure valve with equal displacement according to the present invention;

FIG. 4 is a schematic diagram of the closed space state of the valve body when the constant pressure valve with equal displacement of the present invention is opened;

FIG. 5 is a schematic view of the closed space state of the valve body when the constant pressure valve with equal displacement of the present invention is closed;

FIG. 6 is a schematic diagram of a valve test configuration;

fig. 7 is a graph comparing the test results of the constant pressure valve with the known valve.

The reference numbers illustrate:

1. handle 2, hollow plug 3, upper gland 400 and valve

4. Valve body 40,

stem passages

41, 42, branch inlet 43, flow passage

44. Inlet flow passage 45, fluid inlet 46, fluid outlet 48, outlet flow passage

5. 6, sealing device 560, sealing area 7, valve stem 70, external screw rod

71. 72, groove 8, gasket 9, O-shaped sealing ring 10 and plug

11. Lower gland 12, outer model 13, micro model 14, pressure sensor

15. Pump and method of operating the same

Detailed Description

The utility model provides an equipotential constant pressure valve, have a hollow valve body, the hollow portion of the said valve body forms the valve stem channel, a valve stem can be worn to locate in the said valve stem channel movably, the said valve stem channel is linked together with fluid inlet, fluid outlet separately, said fluid inlet and fluid outlet are linked together with the valve body outside through the inlet runner, outlet runner separately; the two ends of the valve body are sealed by an upper gland and a lower gland, and the valve is characterized in that two sealing devices capable of sealing a valve rod passage are arranged on the valve rod, a sealing area is formed between the two sealing devices, and the sealing area can seal the fluid outlet; the side wall of the valve body is provided with two branch inlets along the length direction of the valve rod, the branch inlets are communicated with the inlet flow channel, and the branch inlets and the fluid inlet are respectively positioned at two sides of the fluid outlet.

The utility model discloses a structure makes the valve rod can keep the fluid total volume unchangeable in the valve runner at the removal in-process to eliminated the pressure oscillation phenomenon of conventional valve at the switching process, consequently, the utility model discloses the small closed system on-off control of specially adapted fluid volume.

In order to clearly understand the technical features, objects and effects of the present invention, the following detailed description of the embodiments, structures, features and effects of the constant pressure valve with equal displacement according to the present invention will be given with reference to the accompanying drawings and preferred embodiments. In addition, through the description of the embodiments, the technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood, however, the attached drawings are only provided for reference and description, and are not used for limiting the present invention.

As shown in fig. 1, fig. 2 and fig. 3, the present invention provides an equal displacement constant pressure valve, which has a hollow valve body 4, wherein the hollow portion of the valve body 4 forms a valve rod channel 40, a valve rod 7 is movably disposed in the valve rod channel 40, the valve rod channel 40 is respectively communicated with a fluid inlet 45 and a fluid outlet 46, and the fluid inlet 45 and the fluid outlet 46 are respectively communicated with the outside of the valve body through an inlet flow passage 44 and an outlet flow passage 48. The two ends of the valve body 4 are sealed by an upper gland 3 and a lower gland 11, wherein the valve rod 4 is provided with two

sealing devices

5 and 6 capable of sealing the valve rod passage 40, a sealing space 560 is formed between the two

sealing devices

5 and 6, and the sealing space 560 can seal the fluid outlet 46. The side wall of the valve body 4 is provided with two

branch inlets

41, 42 along the length direction of the valve stem, the

branch inlets

41, 42 are communicated with an inlet flow passage 44, and the

branch inlets

41, 42 and a fluid inlet 45 are respectively positioned at two sides of a fluid outlet 46.

Wherein the distance L2 between the branch inlet 42 and the fluid outlet 46 near the fluid inlet 45 is greater than or equal to the distance between the two

sealing devices

5, 6.

In a specific embodiment, two

grooves

71, 72 are provided on the valve stem 7, and a sealing ring is embedded in each

groove

71, 72 to form the

sealing devices

5, 6.

Further, the distance L1 between the two

grooves

71, 72 is equal to or less than the distance between the branch inlet 42 near the fluid inlet 45 and the fluid outlet 46. Thereby ensuring that when the two sealing means 5, 6 of the valve stem 7 are respectively located on both sides of said fluid outlet 46 to close the fluid outlet 46 (not in communication with the fluid inlet 45), the sealing means 5, 6 are both located on the lower portion of the branch inlet 42 closest to the fluid outlet 46 and on the upper portion of the fluid inlet 45, see fig. 1 and 5 in combination.

In addition, the diameters of the fluid inlet 45, fluid outlet 46,

branch inlets

41, 42, and inlet and

outlet flow passages

44, 48 are as small as possible, and may be about 0.5mm to about 1.0 mm.

The specific structure of the constant pressure valve with equal displacement of the present invention is described as a specific example with reference to fig. 1 to 3. As shown in the figure, the valve is composed of a valve body 4, a valve rod 7, sealing rings arranged at two ends of the valve body 4 and used for sealing the valve, sealing

devices

5 and 6 arranged on the valve rod 7 and used for opening or closing the valve, an upper press cover 3, a lower press cover 11 and the like, and the main components and functions are as follows:

the valve body 4 has an inlet flow passage 44, an outlet flow passage 48 and a stem passage 40 therein, and the ends of the inlet flow passage 44, the outlet flow passage 48 and the stem passage 40 all have standard internal threaded interfaces. The inlet flow passage 44 is a passage after the fluid enters the valve, the inlet flow passage 44 is communicated with the valve rod passage 40 through the fluid inlet 45 and the

branch inlets

41 and 42, when the valve is opened or closed, the fluid in the valve rod passage 40 can flow in the inlet flow passage through the

branch inlets

41 and 42, and the total volume of the fluid is ensured to be constant in the closed space of the valve body 4. The lower branch inlet 42 of the inlet flow passage 44 is spaced apart from the outlet flow passage 48 by a distance L2. The inlet flow passage 44, the

branch inlets

41, 42 and the outlet flow passage 48 communicating with the stem passageway 40 have diameters of about 0.5mm to about 1.0mm under the conditions satisfying the experiments. By reducing the diameters of the fluid inlet 45, the fluid outlet 46, the

branch inlets

41 and 42, the inlet flow passage 44 and the outlet flow passage 48 as much as possible, the moving resistance of the valve rod 7 is relatively small, the valve is controlled conveniently, the fluid in the passages is reduced to enter the micro model, and the research accuracy of the micro model is improved. . The inner wall of the stem passageway 40 needs to be smooth to reduce resistance to movement of the valve stem 7.

The valve rod 7 is provided with two

grooves

71 and 72, the distance between the two

grooves

71 and 72 is L1, and in the illustrated embodiment, L1 is L2. The upper portion of the valve stem 7 is externally threaded to form an external screw rod 70, and the valve stem 7 is moved up and down relative to the valve body 4 by the rotation of the external screw rod 70. The valve stem 7 forms the

seals

5, 6 by means of sealing rings embedded in the

grooves

71, 72, the

seals

5, 6 being held in close contact with the stem passageway 40 and ensuring that the fluid in the enclosed space 560 formed between the two

seals

5, 6 is isolated from the upper and lower parts of the stem passageway 40.

The two ends of the valve body 4 are provided with pressing covers, namely an upper pressing cover 3 and a lower pressing cover 11 shown in the figure, and the upper pressing cover 3 and the lower pressing cover 11 respectively seal the valve rod 7 through matching with gaskets 8 and O-shaped sealing rings 9 arranged in

accommodating spaces

401 and 402 at the two ends of the valve body 4. The inner parts of the upper and lower press covers 3 and 11 are provided with internal threads which are respectively matched with the hollow plug 2 and the plug 10. The hollow plug 2 is engaged with the outer screw 70 of the valve stem 7, and the valve stem 7 is rotated and linearly moved up and down. The plug 10 is at a certain distance from the bottom end of the valve rod 7, so that the bottom of the valve rod can be kept not to contact with the plug 10 all the time in the moving process of the valve rod 7. The above-mentioned upper and

lower gland

3, 11 and gland that set up at both ends of the valve block 4 and the seal between valve block 4, valve stem 7, and the valve stem 7 realize moving up and down through the cooperation of external screw 70 and hollow plug 10 belong to the prior art, and will not be described here again.

The working principle and working process of the equal displacement constant pressure valve of the present invention will be further described in detail with reference to the accompanying drawings.

From the knowledge of fluid mechanics: in the closed space, under the condition of unchanging fluid volume, objects in the fluid are moved, and the pressure of the closed system cannot be changed.

In the opening process of the conventional valve, the closed space is increased in certain volume due to the lifting of the valve rod, and the pressure in the system is reduced to a certain degree; on the contrary, when the valve is closed, the valve rod moves downwards to reduce the volume of the closed space to reduce the pressure of the system. When the closed volume is larger, the pressure fluctuation is very weak and can be ignored; however, in a space with a small sealed volume such as a micro model, the pressure fluctuation amplitude caused by the operation is large, and the pressure increase is shown in table 1.

TABLE 1 pressure increase during valve closure

The pressure increases in table 1 are destructive to the microscopic glass model due to the slight change in the fluid in the enclosed space as the valve needle is lowered.

In order to overcome the defects of the known valve, especially the destructive influence generated in the microscopic glass model test, the invention provides an equal-displacement constant-pressure control method, in the valve rod displacement process of the valve, the fluid on the compressed side can be supplemented to the other side release space, so that the total volume of the fluid is not changed in the space of the valve flow channel, and the pressure of a closed system (the closed system refers to the microscopic model connected with the valve or the microscopic physical model as referred in the background art) is kept constant in the valve opening and closing process.

One possible solution is to provide

branch inlets

41 and 42 communicating with the fluid inlet 45 on the valve stem channel 40, and to locate the

branch inlets

41 and 42 and the fluid inlet 45 on two sides of the fluid outlet 46, respectively, as shown in fig. 1 and 2, so that during the movement of the valve stem 7, the fluid on one side which is compressed can be supplemented into the space on the other side which is released through the

branch inlets

41 and 42 or the fluid inlet 45. Referring to fig. 4, the fluid-tight space inside the valve body 4 is shown by the shaded portion in fig. 4, and it can be seen that, under the initial condition that the shaded portion has the same fluid pressure, the volume of the shaded portion is not changed in the process of moving the valve rod 7 and the two

sealing devices

5 and 6 up and down, and the fluid pressure in the valve-body-tight space in the process of moving the valve rod 7 is constant.

Specifically, two

sealing devices

5 and 6 composed of two sealing rings are arranged on the valve rod 7, a sealing area 560 is formed between the two sealing rings, when the valve rod 7 and the two sealing rings move to the fluid outlet 46, two sides of the fluid outlet 46 can be sealed, so that the sealing area formed between the fluid outlet 46 and the two sealing rings and an external flow channel of the two sealing rings form two relatively independent pressure spaces, and in the movement process of the valve rod 7, the pressures in the two pressure spaces are kept constant all the time.

When the two seal rings are located on both sides of the fluid outlet 46, the two seal rings are located between the fluid inlet 45 and the branch inlet 42.

Referring to fig. 4 and 5, in the enclosed space of the valve body, the constant pressure control process when the valve rod 7 moves up and down is expressed as follows, and the valve opening and closing process is expressed as follows:

firstly, assuming that the valve body 4 is in an initial state as shown in fig. 4, a fluid (hatched portion) is in a closed space of the valve body 4, and the communication state of an inlet flow passage 44, an annulus formed between the valve stem 7 and the valve body passage 40, an outlet flow passage 48, and the like is known, the valve body is in the closed spaceIs in an isobaric state, is designated as P₀；

Secondly, when the valve rod 7 descends to the state shown in the figure 5, the closed space of the valve body is divided into two parts (A and B); the downlink process is as follows:

a. the lower sealing device 6 of the valve rod 7 descends to the fluid outlet 46, and the upper sealing device 5 of the valve body 7 also descends to the lower branch inlet 42 due to L1 being equal to or less than L2, taking L1 being equal to L2 as an example; during the downward movement, the fluid between the two

sealing devices

5 and 6 disposed on the valve rod 7 flows out along the lower branch inlet 42 to the flow passage 43 communicated with the inlet flow passage 44, while the fluid at the lower part of the sealing device 6 flows into the inlet flow passage 44 through the fluid inlet 45, and the fluid discharged from the valve body passage 40 enters the top space of the sealing device 5 at the upper part of the valve body through the inlet flow passage 44 and the flow passage 43 and the upper branch inlet 41. That is, since the fluid pushed out of the valve body passage 40 by the

seal devices

5 and 6 is supplied to the space increased in the upper part of the valve body passage 40 through the upper branch inlet 41 during the downward movement of the valve stem 7, there is no pressure fluctuation and the pressure is constant at P during the downward movement of the valve stem 7₀；

b. The stage in which the sealing device 6 of the lower part of the valve stem 7 descends through the fluid outlet 46 (the upper sealing device 5 also passes through the lower branch inlet 42); the sealing rings of the

initial sealing devices

5 and 6 are slightly expanded elastically at the fluid inlet 42 and the fluid outlet 46, the sealing ring of the lower sealing device 6 slightly presses the fluid (micro-model) in the outlet flow passage 48, the sealing ring of the upper sealing device 5 slightly presses the fluid in the flow passage 43 communicated with the lower branch inlet 42, and when the width of the sealing ring of the

sealing devices

5 and 6 is smaller than the diameter of each passage and flow passage, the fluctuation is reduced to a large extent by moving the valve rod 7 slowly, so that the influence on the fluid is negligible;

c. the lower sealing means 6 of the valve stem 7 is in the phase of moving downwards towards the fluid outlet 46 (the upper sealing means 5 moves between the lower branch inlet 42 and the fluid outlet 46); because of the equidistant movement (or L1 ≦ L2), A, B in FIG. 5 has two spaces that are relatively independent, forming a constant pressure system in each space.

Because the constant pressure state is maintained in the steps a, b and c, the pressure in the valve body is kept stable in the closing process of the valve rod.

And similarly, when the valve rod 7 moves upwards, the whole system still keeps the pressure unchanged.

In the opening and closing process of the valve, the outer screw rod 70 of the valve rod 7 is matched with the hollow plug 2 by rotating the valve rod 7, so that the valve rod 7 can linearly move up and down. The angular velocity of the rotary valve stem 7 is usually controlled to 90 deg./s or less, thereby effectively reducing the pressure fluctuation at the time of opening and closing the valve.

Will the utility model discloses a valve is applied to and fills out sand micro model to test. The valve 400 is installed outside the outer mold 12 and protected by the ring pressure inside the outer mold 12. The pore volume in micromodel 13 was 0.1mL and the total volume of the tubing connected to the micromodel was 0.3 mL. The ring pressure is 5MPa, the initial pressure in the micro model is 1MPa, the pressure is provided by a quizix micro pump 15, and the pressure change is monitored; the fluid in the quizix micro pump was 9 mL. The test flow is shown in fig. 6, the hatched portion is the fluid path, and the valve 400 position is replaced by the constant pressure valve with equal displacement and the conventional needle valve. Compare the pressure variation of the constant pressure valve with the conventional needle valve with the same displacement of the present invention, see fig. 7. The pressure sensor 14 responds by sensing the pressure on the left side of the valve, which cannot be measured directly and is calculated from the fluid compressibility. The test structure shown in fig. 6 is conventional and will not be described herein.

The test result shows that the pressure fluctuation caused by the conventional needle valve is very large, and the glass model is easily damaged; the constant pressure valve with equal displacement of the utility model is basically constant in pressure when opening and closing.

The above description is only exemplary of the present invention, and is not intended to limit the scope of the present invention. Any person skilled in the art should also realize that such equivalent changes and modifications can be made without departing from the spirit and principles of the present invention. Moreover, it should be noted that the components of the present invention are not limited to the above-mentioned integral application, and various technical features described in the present invention can be selected to be used alone or in combination according to actual needs, so that the present invention naturally covers other combinations and specific applications related to the invention of the present invention.

Claims

1. An equal displacement constant pressure valve is provided with a hollow valve body, wherein the hollow part of the valve body forms a valve rod channel, a valve rod can be movably arranged in the valve rod channel in a penetrating way, the valve rod channel is respectively communicated with a fluid inlet and a fluid outlet, and the fluid inlet and the fluid outlet are respectively communicated with the outside of the valve body through an inlet flow channel and an outlet flow channel; the two ends of the valve body are sealed by an upper gland and a lower gland, and the valve is characterized in that two sealing devices capable of sealing a valve rod passage are arranged on the valve rod, a sealing area is formed between the two sealing devices, and the sealing area can seal the fluid outlet; the side wall of the valve body is provided with two branch inlets along the length direction of the valve rod, the branch inlets are communicated with the inlet flow channel, and the branch inlets and the fluid inlet are respectively positioned at two sides of the fluid outlet.

2. The constant pressure valve of claim 1, wherein a distance between a branch inlet near the fluid inlet and the fluid outlet is greater than or equal to a distance between two of the sealing means.

3. The constant-pressure valve according to claim 1, wherein the valve stem has two grooves, and a sealing ring is embedded in each groove to form the sealing device.

4. An equal-displacement constant-pressure valve as claimed in claim 3, wherein the distance between two of said grooves is equal to or less than the distance between a branch inlet near said fluid inlet and said fluid outlet.

5. The constant pressure valve of claim 1, wherein the fluid inlet, fluid outlet, branch inlet, and inlet and outlet flow passages have a diameter of 0.5mm to 1.0 mm.

6. An equal displacement constant pressure valve as claimed in claim 1, wherein the width of the sealing means is less than the diameter of the inlet and outlet flow passages.