阅读说明：本技术 地面湿蒸汽临界流动流量控制方法及装置 (Ground wet steam critical flow control method and device ) 是由 王顺华 董臣强 杨元亮 于田田 岳继文 孙立柱 陶建强 刘明 任延鹏 于 2020-05-27 设计创作，主要内容包括：本发明公开了地面湿蒸汽临界流动流量控制方法及装置,包括：外喷管,所述外喷管为一个由两端向中间渐缩的喷管；还包括：可变喷管,所述可变喷管整体装入所述外喷管内部,所述可变喷管也为一个由两端向中间渐缩的喷管,可变喷管中间缩颈最小的位置称为喉部；所述可变喷管具有径向伸缩性；过流面积调节机构,所述过流面积调节机构安装在可变喷管的喉部,径向带动喉部扩径或者缩颈。通过旋紧或扭松控制过流面积调节机构,过流面积调节机构径向带动喉部扩径或者缩颈,从而达到改变喉部直径,进而达到控制流量的效果。本发明基于临界流动规律可以通过改变控制装置的结构尺寸来达到改变通过流量控制装置的流量。(The invention discloses a method and a device for controlling ground wet steam critical flow, comprising the following steps: the outer spray pipe is a spray pipe gradually reduced from two ends to the middle; further comprising: the variable nozzle is integrally arranged in the outer nozzle, the variable nozzle is also a nozzle gradually reduced from two ends to the middle, and the position with the minimum necking in the middle of the variable nozzle is called a throat part; the variable nozzle has radial flexibility; and the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe and radially drives the throat part to expand or shrink. The overflowing area adjusting mechanism is controlled by screwing or unscrewing, and the overflowing area adjusting mechanism radially drives the throat part to expand or shrink, so that the diameter of the throat part is changed, and the effect of controlling the flow is achieved. The invention can change the flow passing through the flow control device by changing the structural size of the control device based on the critical flow rule.)

1. A surface wet steam critical flow control device comprising:

the outer spray pipe is a spray pipe gradually reduced from two ends to the middle;

it is characterized by also comprising:

the variable nozzle is integrally arranged in the outer nozzle, the variable nozzle is also a nozzle gradually reduced from two ends to the middle, and the position with the minimum necking in the middle of the variable nozzle is called a throat part; the variable nozzle has radial flexibility;

and the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe and radially drives the throat part to expand or shrink.

2. The ground steam critical flow control device of claim 1, wherein the flow area adjustment mechanism comprises:

the connecting buckle is connected to the throat position of the variable nozzle;

the adjusting valve is a bolt with a handle, is installed in a threaded hole formed in the outer spray pipe in a threaded manner, and the inner end of the adjusting valve is connected with the connecting buckle.

3. The ground steam critical flow control device of claim 2, wherein the connector link comprises:

the variable nozzle comprises at least two circular arc pipes, wherein the circular arc pipes are connected with an adjusting valve and are also connected with the throats of the variable nozzles; each circular arc pipe is provided with an adjusting valve;

and two ends of the arc rod respectively extend into the two adjacent arc tubes.

4. The ground steam critical flow control device of claim 3, wherein the connector link further comprises:

the anti-falling limiting mechanism comprises an expanding sheet and a necking shoulder, the expanding sheet is connected to the end of the arc rod, the necking shoulder is installed on the inner wall of an end opening of the arc tube, and the outer diameter of the expanding sheet is larger than the inner diameter of the necking shoulder.

5. The ground wet steam critical flow control device of claim 4, wherein the outside diameter of the expanding plate is smaller than the inside diameter of the circular arc tube, and the inside diameter of the necking shoulder is larger than the outside diameter of the circular arc rod.

6. The ground wet steam critical flow control device of claim 1, 2, 3, 4 or 5, wherein the inner walls of the two end ports of the outer nozzle are provided with an insertion ring groove, and the end of the variable nozzle is inserted into the insertion ring groove.

7. The ground wet steam critical flow control device of claim 1, 2, 3, 4 or 5, further comprising:

a self-adjusting float housed inside the variable nozzle, proximate the throat location.

8. The ground moisture vapor critical flow control device of claim 7, wherein the self-adjusting float front end is connected to a front support spring, the front support spring is connected to a front support bracket, and the front support bracket is fixed to the inner wall of the outer nozzle front port; the rear end of the self-adjusting floater is connected with a rear supporting spring, the rear supporting spring is connected with a rear end support, and the rear end support is fixed on the inner wall of the rear end opening of the outer spray pipe.

9. The ground wet steam critical flow control method is characterized by comprising the following steps of:

the variable spray pipe is integrally arranged in the outer spray pipe, and is also a spray pipe gradually reduced from two ends to the middle; the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe; the variable spray pipe is made of a material with radial elasticity;

the overflowing area adjusting mechanism is controlled by screwing or unscrewing, and the overflowing area adjusting mechanism radially drives the throat part to expand or shrink, so that the diameter of the throat part is changed, and the effect of controlling the flow is achieved.

10. The method for controlling the ground surface wet steam critical flow rate as claimed in claim 9, wherein the specific adjusting steps of the flow area adjusting mechanism are as follows:

through screwing or unscrewing the regulating valve, the regulating valve radially pulls or extrudes the arc pipes, the arc pipes are close to each other, the arc rods also gradually extend into the arc pipes, the arc rods can limit the arc pipes to only enlarge or reduce in a circular manner, and the arc pipes can be enlarged or reduced in the inner diameter of the throat part of the variable spray pipe.

11. The method of claim 9 or 10, wherein when critical flow occurs, the relationship between the flow through the variable nozzle and the variable nozzle throat diameter is:

wherein a and b are coefficients obtained by indoor and field tests, M_tThe unit is t/h, and is the mass flow of steam; p_uPressure upstream of the venturi nozzle in MPa; d isThroat diameter in mm; x is the steam dryness, which is the decimal fraction.

12. The critical flow control method of ground wet steam according to claim 9 or 10, wherein a self-regulating float is provided inside the variable nozzle, and when the inlet pressure fluctuates when the wet steam fluid passes through the variable nozzle, the inlet pressure fluctuation can be overcome by the self-regulating function of the spring float, so that the inlet pressure can also maintain the inlet pressure of the critical flow, and the flow can be kept constant regardless of the reduction of the outlet pressure.

Technical Field

The invention relates to the technical field of thick oil recovery steam flow control, in particular to a method and a device for controlling ground wet steam critical flow.

Background

In the process of thick oil exploitation of an oil layer, because the viscosity of the super thick oil is high, the flowing capacity under the condition of the oil layer is low, the steam huff and puff investment in a thermodynamic method is low, the process technology is simple, and the yield is increased quickly, so that the method is a preferred oil extraction method.

The main reasons for adopting flow measurement in steam injection wells are two:

(1) safety, in the steam injection system, the amount of wet steam injected into different wells is different, and a valve is required to be used for regulation and control according to the change of a flow meter, so that the safety is realized by using a differential pressure type flow meter and a control valve frequently. If a control valve and a flow meter are not used, the steam injection amount of each well is not controlled, uneven steam distribution can be generated, and even safety accidents can happen;

(2) and the economical efficiency is realized, and the proper amount of steam is introduced according to the scale of each well, so that the waste of steam resources is avoided, and the purposes of reducing the thermal recovery cost and improving the economic benefit are achieved. Therefore, parameters of the steam injection system need to be monitored and controlled, and the control of steam is also important in the thermal recovery process.

The main application of steam flow monitoring in current common steam injection steam systems is a differential pressure type flowmeter. When fluid passes through the throttling device, the cross section of the fluid is contracted due to the change of the pipe diameter or the influence of other factors, the fluid speed is increased and the pressure is reduced at the cross section, so that pressure difference occurs at two ends of the throttling device, and then the flow value can be obtained by combining the Bernoulli equation and the continuity equation.

Application No.: 92242205.2, filing date: 1992-11-20 a Laval nozzle pressure-reducing water saver for controlling the flow in public and indoor pipeline systems is composed of a nut 2 with a stepped cavity 10, a Laval nozzle 1 arranged in the cavity 10, an end face fastening cover 3 in threaded connection with one end of the nut 2, a pipe joint 5 connected with a threaded hole 11 on the side face of the nut 2, and a throttle valve 6 respectively connected with the pipe joint 5 and an outlet 7 of the water saver. The water economizer utilizes the energy of tap water to realize the automatic control of water flow in a certain range, stabilize the water outlet flow and achieve the aim of water saving.

The invention discloses an incompressible fluid critical flow device with adjustable flow rate, which is published by the national western safety traffic university and has the patent number of ZL201410085529.8, and the incompressible fluid critical flow device with adjustable flow rate comprises a circular tubular shell, wherein an orifice plate with a rectangular inner hole is coaxially fixed in the circular tubular shell, two flow rate self-adjusting chambers are symmetrically arranged at the left and right positions outside the circular tubular shell corresponding to the orifice plate, and two critical flow self-controlling chambers are symmetrically arranged at the upper and lower positions; maintaining the upstream flow parameters of the device constant, when the downstream pressure reaches a certain critical value, the flow passing through the device reaches a maximum value, and if the downstream pressure is continuously reduced, the acting flow passing through the critical flow automatic control chamber is kept constant, namely, the critical flow is realized; when the upstream pressure of the device changes, the flow self-regulating chamber can automatically regulate the flow according to the upstream pressure; the device can realize the critical flow of the incompressible fluid, overcomes the defects of high flow rate, large pressure loss, and poor noise and safety performance of the conventional incompressible fluid based on the cavitation principle to realize the critical flow, and can adjust the critical flow, thereby effectively improving the application range of the incompressible fluid critical flow device. The invention discloses a critical flow venturi nozzle based on the mechanical choking principle at the university of Yangtze river, and the invention patent number is ZL 201710641683.2. A critical flow Venturi nozzle based on the mechanical choking principle comprises a convergent-divergent Venturi nozzle body, wherein the Venturi nozzle body consists of a head contraction section, a throat straight pipe section and a tail diffusion section which are sequentially connected; an upstream mounting pore plate is arranged at the inlet end of the venturi nozzle body positioned at the head contraction section, and a downstream mounting pore plate is arranged at the outlet end of the venturi nozzle body positioned at the tail diffusion section; a guide rod penetrates through the inner cavity of the Venturi nozzle body, and the central axis of the guide rod is superposed with the central axis of the Venturi nozzle body; the guide rod is sleeved with a floater which crosses over the straight throat pipe section and is used for controlling the flow of fluid, and the floater can axially slide along the guide rod under the driving of the fluid to form a flow passage with a variable area with the straight throat pipe section. The invention can realize the critical flow of the incompressible fluid under the conditions of lower flow speed and smaller resistance loss, and can simultaneously shield the influence of upstream and downstream pressure disturbance on the flow. All are designed according to the critical flow principle, which has the advantage of solving the problem of limitation of installation conditions, so that the measuring device can be used in various situations. The change of energy flow parameter minimization is ensured, the influence of pressure loss on the steam injection effect is reduced, and the control and regulation range of the flowmeter is enlarged. But the disadvantages are also obvious and the installation conditions are strict. The requirement of longer straight pipe sections before and after the differential pressure type flowmeter may not be possible to arrange in an actual steam injection system due to space limitations. The measurement range is narrow, and the application limitation is large. In the steam injection pipeline, the fluid is wet steam, and the flow of the two-phase fluid is difficult to measure by using a differential pressure type flowmeter. The pressure loss is large and the measurement is difficult for the pipeline with smaller diameter. The requirement for controlling the energy flow parameters of the pressure in the steam injection pipeline is high, the overall steam injection effect is influenced by overlarge pressure loss, and the situation of overlarge pressure loss needs to be avoided.

The technical scheme of the disclosed technology, the technical problems to be solved and the beneficial effects are all different from the technical scheme of the invention, or the technical field or the application occasion is different, and no technical inspiration exists in the technical scheme disclosed above.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art, and providing a flow control device and a method thereof, which can change the flow rate of wet vapor fluid through the flow control device by changing the structural dimension of the control device based on the critical flow law.

In order to achieve the purpose, the invention adopts the following technical scheme:

a surface wet steam critical flow control device comprising:

the outer spray pipe is a spray pipe gradually reduced from two ends to the middle;

further comprising:

the variable nozzle is integrally arranged in the outer nozzle, the variable nozzle is also a nozzle gradually reduced from two ends to the middle, and the position with the minimum necking in the middle of the variable nozzle is called a throat part; the variable nozzle has radial flexibility;

and the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe and radially drives the throat part to expand or shrink.

Further, the flow area adjustment mechanism includes:

the connecting buckle is connected to the throat position of the variable nozzle;

the adjusting valve is a bolt with a handle, is installed in a threaded hole formed in the outer spray pipe in a threaded manner, and the inner end of the adjusting valve is connected with the connecting buckle.

Further, the connector link includes:

the variable nozzle comprises at least two circular arc pipes, wherein the circular arc pipes are connected with an adjusting valve and are also connected with the throats of the variable nozzles; each circular arc pipe is provided with an adjusting valve;

and two ends of the arc rod respectively extend into the two adjacent arc tubes.

Further, the connector link further comprises:

the anti-falling limiting mechanism comprises an expanding sheet and a necking shoulder, the expanding sheet is connected to the end of the arc rod, the necking shoulder is installed on the inner wall of an end opening of the arc tube, and the outer diameter of the expanding sheet is larger than the inner diameter of the necking shoulder.

Further, the outer diameter of the expanding sheet is smaller than the inner diameter of the arc tube, and the inner diameter of the necking shoulder is larger than the outer diameter of the arc rod.

Furthermore, the inner walls of the two ports of the outer spray pipe are respectively provided with an insertion ring groove, and the end part of the variable spray pipe is inserted into the insertion ring grooves.

Further, still include:

a self-adjusting float housed inside the variable nozzle, proximate the throat location.

Furthermore, the front end of the self-adjusting floater is connected with a front supporting spring, the front supporting spring is connected with a front end bracket, and the front end bracket is fixed on the inner wall of the front port of the outer spray pipe; the rear end of the self-adjusting floater is connected with a rear supporting spring, the rear supporting spring is connected with a rear end support, and the rear end support is fixed on the inner wall of the rear end opening of the outer spray pipe.

In order to achieve the purpose, the invention adopts the following technical scheme:

the ground wet steam critical flow control method comprises the following steps:

the variable spray pipe is integrally arranged in the outer spray pipe, and is also a spray pipe gradually reduced from two ends to the middle; the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe; the variable spray pipe is made of a material with radial elasticity;

the overflowing area adjusting mechanism is controlled by screwing or unscrewing, and the overflowing area adjusting mechanism radially drives the throat part to expand or shrink, so that the diameter of the throat part is changed, and the effect of controlling the flow is achieved.

Further, the specific adjusting steps of the flow area adjusting mechanism are as follows:

through screwing or unscrewing the regulating valve, the regulating valve radially pulls or extrudes the arc pipes, the arc pipes are close to each other, the arc rods also gradually extend into the arc pipes, the arc rods can limit the arc pipes to only enlarge or reduce in a circular manner, and the arc pipes can be enlarged or reduced in the inner diameter of the throat part of the variable spray pipe.

Further, when critical flow occurs, the relationship between the flow through the variable nozzle and the variable nozzle throat diameter is:

wherein a and b are coefficients obtained by indoor and field tests, M_tThe unit is t/h, and is the mass flow of steam; p_uPressure upstream of the venturi nozzle in MPa; d is the diameter of the throat in mm; x is the steam dryness, which is the decimal fraction.

Further, set up self-interacting float in variable nozzle, when wet steam fluid passes through variable nozzle, when inlet pressure takes place to fluctuate, through spring float's self-interacting function, can overcome inlet pressure fluctuation for inlet pressure can also maintain the inlet pressure of critical flow, reduces the outlet pressure no matter how, and the flow can still remain unchanged all the time.

Compared with the prior art, the invention has the following beneficial effects:

the invention ensures the accuracy of flow control by corresponding different flow rates through different straight pipes at the throat part of the spray pipe. Different throat sizes can be adjusted according to the actual production process to achieve the effect of controlling the flow.

The invention achieves the effect of controlling the flow by the special state of the spray pipe, reduces the cost input and has higher return.

The ground wet steam critical flow control device has a simple structure, avoids a complex regulation and control process, and is directly designed and used to achieve an ideal effect. The spray pipe is simple in structure, complex operation is omitted, and the diameter of the throat part is adjusted according to different flow rates.

The flow control device and the method are suitable for regulating and metering the wet steam fluid.

Drawings

FIG. 1 is a schematic structural diagram of a ground wet steam critical flow control device according to the present invention;

FIG. 2 is a schematic view of the connection buckle;

fig. 3 is a schematic structural diagram of a ground wet steam critical flow control device according to a second embodiment of the invention.

In the figure: 1. an outer nozzle; 2. a connecting buckle; 3. adjusting a valve; 4. a variable nozzle; 5. a fixed end; 6. a front end bracket; 7. a support spring; 8. a self-adjusting float; 9. a rear end bracket.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

referring to fig. 1 to 2, fig. 1 shows an improved laval nozzle, which is divided into an outer housing and an inner housing, wherein the outer housing and the inner housing are connected by a connecting buckle, the inlet diameter is 90mm, the throat diameter of the outer housing is 69.9mm, the length of the tapered section is 253.6mm, the throat diameter of the inner housing can be adjusted by an external adjusting valve, the valve is located above and below the throat, and the outlet diameter of the inner housing is controlled to change by screwing or unscrewing, so that the throat diameter is changed, and the flow control effect is achieved. Fig. 2 shows the working principle of reducing the diameter of the shell, and the effect of controlling the diameter change is achieved mainly by the flexibility of the tough steel plate. The throat expansion angle of the nozzle is ensured to be between 0 DEG and 5 DEG, so that the accurate control of the flow and the realization of the measuring device can be ensured, the controllable pressure of the energy flow parameters of the wet steam at the front and rear outlet sections of the nozzle is between 10MPa and 15MPa, the dryness is between 0.5 and 0.8, and finally the required flow control of the wet steam within the range of 1.5Kg/s to 5Kg/s is realized.

The invention provides a technical scheme that:

a surface wet steam critical flow control device comprising:

the outer spray pipe 1 is a spray pipe which is gradually reduced from two ends to the middle, and is a Laval spray pipe before improvement;

further comprising:

the variable nozzle 4 is integrally arranged in the outer nozzle, the variable nozzle is also a nozzle gradually reduced from two ends to the middle, and the position with the minimum necking in the middle of the variable nozzle is called a throat part; the variable nozzle has radial flexibility;

and the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe and radially drives the throat part to expand or shrink.

Further, the flow area adjustment mechanism includes:

the connecting buckle 2 is connected to the throat position of the variable nozzle;

and the adjusting valve 3 is a bolt with a handle, is arranged in a screw hole formed in the outer spray pipe in a screw thread mode, and the inner end of the adjusting valve is connected with the connecting buckle.

Further, the connector link includes:

the variable nozzle comprises at least two circular arc pipes 21, wherein the circular arc pipes are connected with an adjusting valve and further connected with the throat part of the variable nozzle; each circular arc pipe is provided with an adjusting valve;

and the two ends of the arc rod 22 respectively extend into the two adjacent arc tubes.

Further, the connector link further comprises:

the anti-drop limiting mechanism comprises an expanding sheet and a necking shoulder, the expanding sheet is connected to the end portion of the arc rod, the necking shoulder is installed on the inner wall of the end opening of the arc tube, the outer diameter of the expanding sheet is larger than the inner diameter of the necking shoulder, and although the components are not given reference numerals, the drawing is clear.

Further, the outer diameter of the expanding sheet is smaller than the inner diameter of the arc tube, and the inner diameter of the necking shoulder is larger than the outer diameter of the arc rod.

Further, an insertion ring groove, namely a fixed end 5, is arranged on the inner wall of each of the two ports of the outer nozzle, and the end of the variable nozzle is inserted into the insertion ring groove.

Further, still include:

a self-adjusting float 8 housed inside the variable nozzle, close to the throat position.

Furthermore, the front end of the self-adjusting floater is connected with a front supporting spring, the front supporting spring is connected with a front end bracket 6, and the front end bracket is fixed on the inner wall of the front port of the outer spray pipe; the rear end of the self-adjusting float is connected with a rear supporting spring, the rear supporting spring is connected with a rear end support 9, and the rear end support is fixed on the inner wall of the rear end opening of the outer spray pipe.

The ground wet steam critical flow control method comprises the following steps:

the variable spray pipe is integrally arranged in the outer spray pipe, and is also a spray pipe gradually reduced from two ends to the middle; the flow area adjusting mechanism is arranged at the throat part of the variable spray pipe; the variable spray pipe is made of a material with radial elasticity;

the overflowing area adjusting mechanism is controlled by screwing or unscrewing, and the overflowing area adjusting mechanism radially drives the throat part to expand or shrink, so that the diameter of the throat part is changed, and the effect of controlling the flow is achieved.

Further, the specific adjusting steps of the flow area adjusting mechanism are as follows:

through screwing or unscrewing the regulating valve, the regulating valve radially pulls or extrudes the arc pipes, the arc pipes are close to each other, the arc rods also gradually extend into the arc pipes, the arc rods can limit the arc pipes to only enlarge or reduce in a circular manner, and the arc pipes can be enlarged or reduced in the inner diameter of the throat part of the variable spray pipe.

Further, set up self-interacting float in variable nozzle, when wet steam fluid passes through variable nozzle, when inlet pressure takes place to fluctuate, through spring float's self-interacting function, can overcome inlet pressure fluctuation for inlet pressure can also maintain the inlet pressure of critical flow, reduces the outlet pressure no matter how, and the flow can still remain unchanged all the time.

The method is characterized in that the Laval nozzle is slightly changed, the aperture of the Laval nozzle is gradually reduced, the smallest aperture part is a nozzle throat part, and a flow channel with gradually increased aperture is arranged behind the nozzle throat part. When the upstream pressure and the downstream pressure of the convergent-divergent nozzle meet a certain relation, the gas flow speed at the throat part of the nozzle reaches local factors, the nozzle reaches a critical state, and the mass flow of the gas flowing through the nozzle is only related to the upstream pressure and is not related to the downstream pressure.

When critical flow occurs, the relationship between the flow through the variable nozzle and the diameter of the variable nozzle throat:

wherein a and b are coefficients obtained by indoor and field tests, M_tIs the mass flow rate (t/h), P, of the steam_uIs the pressure (MPa) upstream of the Venturi nozzle, d is the throat diameter (mm), and X is the steam quality, which is the decimal fraction.

Through modified Laval nozzle divide into shell body and interior casing, interior, shell body pass through the connector link and connect, and its internal casing throat diameter can be adjusted through outside adjusting valve, and the valve is located about the throat, changes through the export diameter of screwing or the pine control interior casing to reach and change throat diameter, and then reach control flow's effect.

The working principle of the inner shell reducing mainly depends on the flexibility of the tough steel plate to achieve the effect of controlling the diameter change. The throat expansion angle of the nozzle is ensured to be between 0 DEG and 5 DEG, so that the accurate control of the flow and the realization of the measuring device can be ensured, the controllable pressure of the energy flow parameters of the wet steam at the front and rear outlet sections of the nozzle is between 10MPa and 15MPa, the dryness is between 0.5 and 0.8, and finally the required flow control of the wet steam within the range of 1.5Kg/s to 5Kg/s is realized.

When wet steam fluid passes through the Laval nozzle, the inlet pressure is kept unchanged, when the outlet pressure is critical pressure, the outlet pressure is reduced no matter how, the flow is always kept unchanged, and at the moment, the flow passing through the Laval nozzle can be changed by changing the diameter of the throat part of the Laval nozzle.

By changing the diameter of the throat part, the opening and closing of the connecting buckle with the pipe diameter specially designed can be changed by rotating the regulating valve in the middle, so that the change of the pipe diameter of the throat part is controlled, and the change of the flow of the device is controlled.

Example 2:

referring to fig. 1 to 3, in embodiment 1, the inlet pressure is kept stable, and in embodiment 2, when the inlet pressure fluctuates when the wet vapor fluid passes through the laval nozzle, the inlet pressure fluctuation can be overcome by the self-adjusting function of the spring float, so that the inlet pressure can also maintain the inlet pressure of the critical flow, and the flow rate can be kept constant regardless of the reduction of the outlet pressure. Flow control is also achieved by adjusting the valve to vary the throat diameter.

All parts and parts which are not discussed in the present application and the connection mode of all parts and parts in the present application belong to the known technology in the technical field, and are not described again. Such as welding, threaded connections, etc.

In the present invention, the term "plurality" means two or more unless explicitly defined otherwise. The terms "mounted," "connected," "fixed," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, a removable connection, or an integral connection; "coupled" may be direct or indirect through an intermediary. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", "front", "rear", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or unit must have a specific direction, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.