阅读说明：本技术 一种用于lng船低温管路的充惰性气体换向阀 (Inert gas filling reversing valve for low-temperature pipeline of LNG ship ) 是由 李晓龙 陈琰 陈炼 于春林 刘鹏鹏 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种用于LNG船低温管路的充惰性气体换向阀,包括阀体,所述阀体内部设置有第一进气阀腔、第二进气阀腔和出气阀腔,第一进气阀腔、第二进气阀腔和出气阀腔之间通过连接流道相连通,第一进气阀腔、第二进气阀腔和出气阀腔内均安装有开关阀组,第一进气阀腔内还设置有用以使其阀腔进气口保持常开状态的限位组件。本发明可以根据气体流量大小及时切换其进气阀腔,以将低温管路内的残留空气全部排出,同时也能够控制焊接过程中低温管路内的惰性气体含量,避免焊接过程中焊缝被氧化,有效保证焊接质量。(The invention discloses an inert gas filling reversing valve for a low-temperature pipeline of an LNG ship, which comprises a valve body, wherein a first gas inlet valve cavity, a second gas inlet valve cavity and a gas outlet valve cavity are arranged in the valve body, the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity are communicated through connecting flow passages, switch valve groups are arranged in the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity, and a limiting assembly used for enabling a gas inlet of the valve cavity to be in a normally open state is further arranged in the first gas inlet valve cavity. The gas inlet valve cavity can be switched in time according to the gas flow so as to discharge all residual air in the low-temperature pipeline, and meanwhile, the content of inert gas in the low-temperature pipeline in the welding process can be controlled, so that the welding seam is prevented from being oxidized in the welding process, and the welding quality is effectively ensured.)

1. The inert gas filling reversing valve for the low-temperature pipeline of the LNG ship is characterized by comprising a valve body, wherein a first gas inlet valve cavity, a second gas inlet valve cavity and a gas outlet valve cavity are arranged in the valve body, the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity are communicated through connecting flow channels, switch valve groups are arranged in the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity, and a limiting assembly used for enabling a gas inlet of the valve cavity to be in a normally open state is further arranged in the first gas inlet valve cavity;

when the gas flow is in a first set flow range, the gas flows out of the valve body along the first gas inlet valve cavity, the connecting flow passage and the gas outlet valve cavity;

when the gas flow is increased to a second set flow range, the switch valve groups in the first gas inlet valve cavity and the second gas inlet valve cavity move towards the gas outlets of the respective valve cavities under the action of gas pressure, so that the gas outlet of the first gas inlet valve cavity is closed, the gas inlet of the second gas inlet valve cavity is opened, and the gas flows out of the valve body along the second gas inlet valve cavity, the connecting flow passage and the gas outlet valve cavity.

2. The inert gas filling reversing valve for the LNG ship cryogenic pipeline as claimed in claim 1, wherein sealing seats are further arranged between the contact positions of the switch valve groups in the first inlet valve cavity, the second inlet valve cavity and the outlet valve cavity and the valve cavities of the switch valve groups.

3. The inert gas filling reversing valve for the LNG carrier cryogenic pipeline as claimed in claim 2, wherein the sealing seats are sealing rings arranged at the valve cavity gas inlet and the valve cavity gas outlet or sealing gaskets which are attached and fixed on the inner wall of the valve cavity and matched with the shape of the inner wall of the valve cavity.

4. The inert gas-filled reversing valve for the LNG ship cryogenic line of claim 1 or 2, characterized in that the switch valve group comprises a spring and a valve core fixedly connected with the spring.

5. The inert gas filled reversing valve for the LNG ship cryogenic line of claim 4, characterized in that the elasticity of the spring in the first inlet valve chamber is less than the elasticity of the spring in the second inlet valve chamber, and the elasticity of the spring in the outlet valve chamber is equal to the elasticity of the spring in the first inlet valve chamber.

6. The inert gas filling reversing valve for the LNG ship cryogenic pipeline according to claim 1, wherein the limiting assembly comprises a limiting seat fixedly connected with the valve body, a threaded seat fixed in the limiting seat, and an adjusting rod fixed in the threaded seat, and the bottom of the adjusting rod extends out of the threaded seat and abuts against the switch valve block of the first gas inlet valve cavity.

7. The inert gas-filled reversing valve for the cryogenic pipeline of the LNG ship as claimed in claim 6, wherein the adjusting rod is a screw with a straight groove at the top.

8. The inert gas filled reversing valve for the LNG ship cryogenic line of claim 6, characterized in that the limiting seat is composed of a tubular seat body and a seat ring uniformly arranged in the tubular seat body, and the seat ring is arranged along a radial direction of the tubular seat body.

Technical Field

The invention relates to the technical field of ship construction, in particular to an inert gas filling reversing valve for a low-temperature pipeline of an LNG ship.

Background

The LNG ship low-temperature pipeline is an important component of the whole low-temperature system, and plays a role in conveying liquefied natural gas (-163 ℃), and the pipeline is arranged in a horizontal state along a deck surface of a dome of the LNG ship.

The low-temperature pipelines are arranged in a mode of sequentially connecting from the head end to the tail end one by one, and the pipe fittings are fixed by iron-embedded spot welding.

Because the low-temperature pipeline is made of low-temperature austenitic stainless steel, the material is extremely easy to oxidize in the welding process to directly generate welding defects, and any tiny defect can cause the low-temperature pipeline to break in the use process and cause natural gas leakage, so that the generated consequence is unreasonable.

Therefore, before welding the low-temperature pipeline, sealing tools such as sponge and the like are required to be arranged behind the welding line for plugging the pipeline at a certain distance, and inert gas (pipeline inerting for short) is filled into the pipeline from the end part of the pipeline after plugging is finished. The inert gas in the low-temperature pipeline is argon gas with a large specific gravity generally according to the welding requirement, the content of the inert gas needs to reach a standard concentration of not less than 98%, and air (oxygen) is discharged from a groove gap (a coated adhesive tape is torn) of a welding seam so as to ensure that the welding seam is not oxidized in the welding process, as shown in fig. 8.

At present, when a pipeline is inerted, whether the inerting of the pipeline meets requirements is generally judged by measuring the oxygen content in air exhausted from a gap of a groove of a welding seam, and when an oxygen meter detects that the oxygen content is less than 2%, welding operation can be carried out. The continuous supply of inert gas is required during the welding process to maintain the inert gas content inside the tube.

However, the length of the low-temperature pipeline with the DN being more than or equal to 300mm is long, the pipeline system arrangement (branch pipes and equipment interfaces) and the pipeline trend (up-down bending and left-right bending) are various, air and residual air inside the pipeline cannot be rapidly discharged in the actual inflation process, some air can be remained and accumulated inside the pipeline, the residual air is mainly concentrated between the welding line and the sealing tool along with inflation, as shown in fig. 9, because the residual air cannot be discharged, the content of inert gas at the position of the welding line cannot be guaranteed, and the production progress can be greatly influenced. Meanwhile, because residual air cannot be discharged, the quality of the welding seam can be directly influenced along with the continuous spread of the inert gas to the position of the welding seam in the welding process.

Disclosure of Invention

In view of the above, the present invention provides an inert gas-filled reversing valve for a cryogenic pipeline of an LNG ship, which is used to solve the above problems in the background art.

The inert gas filling reversing valve for the low-temperature pipeline of the LNG ship comprises a valve body, wherein a first gas inlet valve cavity, a second gas inlet valve cavity and a gas outlet valve cavity are arranged in the valve body, the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity are communicated through connecting flow channels, switch valve groups are arranged in the first gas inlet valve cavity, the second gas inlet valve cavity and the gas outlet valve cavity, and a limiting component used for enabling a gas inlet of the valve cavity to be in a normally open state is further arranged in the first gas inlet valve cavity;

when the gas flow is in a first set flow range, the gas flows out of the valve body along the first gas inlet valve cavity, the connecting flow passage and the gas outlet valve cavity;

when the gas flow is increased to a second set flow range, the switch valve groups in the first gas inlet valve cavity and the second gas inlet valve cavity move towards the gas outlets of the respective valve cavities under the action of gas pressure, so that the gas outlet of the first gas inlet valve cavity is closed, the gas inlet of the second gas inlet valve cavity is opened, and the gas flows out of the valve body along the second gas inlet valve cavity, the connecting flow passage and the gas outlet valve cavity.

Preferably, sealing seats are further arranged between the switching valve groups in the first air inlet valve cavity, the second air inlet valve cavity and the air outlet valve cavity and contact positions of the respective valve cavities.

Preferably, the sealing seat is a sealing ring arranged at the air inlet of the valve cavity and the air outlet of the valve cavity or a sealing gasket which is attached and fixed on the inner wall of the valve cavity and is matched with the shape of the inner wall of the valve cavity.

Preferably, the switch valve group comprises a spring and a valve core fixedly connected with the spring.

Preferably, the elasticity of the spring in the first air inlet valve cavity is smaller than that of the spring in the second air inlet valve cavity, and the elasticity of the spring in the air outlet valve cavity is equal to that of the spring in the first air inlet valve cavity.

Preferably, the limiting assembly comprises a limiting seat fixedly connected with the valve body, a threaded seat fixed in the limiting seat, and an adjusting rod fixed in the threaded seat, and the bottom of the adjusting rod extends out of the threaded seat and abuts against the switch valve group of the first air inlet valve cavity.

Preferably, the adjusting rod is a screw rod with a straight groove at the top.

Preferably, the limiting seat is composed of a tubular seat body and a seat ring uniformly arranged in the tubular seat body, and the seat ring is arranged along the radial direction of the tubular seat body.

The invention has the beneficial effects that:

this application can in time switch its air inlet valve chamber according to gas flow size to with the whole discharges of residual air in the low temperature pipeline, also can control the inert gas content in the low temperature pipeline in the welding process simultaneously, avoid welding process in the welding seam by the oxidation, effectively guarantee welding quality.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a schematic structural view of the limiting assembly.

Fig. 3 is a schematic view of the stop assembly installed in the first intake valve cavity.

FIG. 4 is a schematic diagram showing the on-off state of each valve cavity in the valve before the valve is used.

FIG. 5 is a schematic illustration of gas flow from the first inlet chamber into the diverter valve within a first set flow range.

FIG. 6 is a schematic view of gas entering the reversing valve from the second inlet chamber at a second set flow range.

Fig. 7 is a schematic view of one of the structures of the seal holder.

Fig. 8 and 9 are schematic diagrams illustrating air discharge from the inside of the pipe in the related art.

The reference numerals in the figures have the meaning:

the valve comprises a valve body 1, a first air inlet valve cavity 2, a second air inlet valve cavity 3, an air outlet valve cavity 4, a connecting flow channel 5, a switching valve group 6, a spring 7, a valve core 8, a limiting component 9, a limiting seat 10, a threaded seat 11, an adjusting rod 12, a tubular seat body 13, a seat ring 14, a sealing seat 15, an air inlet pipe 16, an air outlet pipe 17, a welding line 18, an inert gas 19, an air 20 and a sponge plug 21.

Detailed Description

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all 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.

The present application is described in further detail below with reference to specific embodiments and with reference to the attached drawings.

In the description of the present application, unless explicitly stated or limited otherwise, the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless specified or indicated otherwise; the terms "connected" and "fixed" are used in a broad sense, for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. 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 application, it should be understood that the terms "upper", "lower", "left", "right", and the like used in the embodiments of the present application are described with reference to the angles shown in the drawings, and should not be construed as limiting the embodiments of the present application. In addition, in this context, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on "or" under "the other element or be indirectly on" or "under" the other element via an intermediate element.

The invention provides an inert gas filling reversing valve for a low-temperature pipeline of an LNG ship, which comprises a valve body 1, wherein a first gas inlet valve cavity 2, a second gas inlet valve cavity 3 and a gas outlet valve cavity 4 are arranged in the valve body, and the first gas inlet valve cavity 2, the second gas inlet valve cavity 3 and the gas outlet valve cavity 4 are communicated through a connecting flow passage 5.

And switch valve groups 6 are arranged in the first air inlet valve cavity 2, the second air inlet valve cavity 3 and the air outlet valve cavity 4. The switch valve groups 6 in the three valve cavities have the same structure and respectively comprise a spring 7 and a valve core 8 fixedly connected with the spring 7, and the spring in each valve cavity is fixed on a step at the air outlet of the valve cavity.

In this embodiment, the elasticity of the spring in the first air inlet valve cavity 2 is smaller than that of the spring in the second air inlet valve cavity 3, and the elasticity of the spring in the air outlet valve cavity 4 is equal to that of the spring in the first air inlet valve cavity 2.

And a limiting assembly 9 used for keeping the air inlet of the valve cavity in a normally open state is further arranged in the first air inlet valve cavity 2. The limiting assembly 9 not only has the function of keeping the valve cavity air inlet of the first air inlet valve cavity 2 normally open, but also has the function of adjusting the maximum flow which can be borne by the switch valve group in the first air inlet valve cavity 2.

Specifically, the limiting assembly 9 includes a limiting seat 10 fixedly connected to the valve body 1, a threaded seat 11 fixed in the limiting seat 10, and an adjusting rod 12 fixed in the threaded seat 11, and a bottom of the adjusting rod 12 extends out of the threaded seat 11 and abuts against the valve block of the first air inlet valve cavity 2. In this embodiment, the limiting seat 10 is composed of a tubular seat body 13 and a seat ring 14 uniformly arranged in the tubular seat body 13, and the seat ring 14 is arranged along the radial direction of the tubular seat body 13; the adjusting rod 12 is a screw rod with a straight groove at the top.

After the valve of the present invention is used for a long time, the spring in the first intake valve chamber 2 may be fatigued, thereby affecting the accuracy of on-off. For example, when the valve is initially used, the maximum flow threshold value which can be borne by the switch valve group in the first air inlet valve cavity 2 is 10L/min, when the gas flow is less than 10L/min, the first air inlet valve cavity 2 is long-pass, and when the gas flow is more than 10L/min, the first air inlet valve cavity 2 is closed; if the valve is used for a long time, the spring is fatigued, and the phenomenon that the first gas inlet valve cavity 2 is closed in advance when the gas flow rate does not reach 10L/min possibly occurs, so that the discharging effect of residual gas in the low-temperature pipeline is influenced, and at the moment, the maximum flow threshold value born by the switch valve group can be readjusted to 10L/min by screwing the adjusting rod 12.

Preferably, a sealing seat 15 is further arranged between the contact positions of the switch valve group and the valve cavity in the first air inlet valve cavity 2, the second air inlet valve cavity 3 and the air outlet valve cavity 4. In this embodiment, the sealing seat 15 is a sealing ring (as shown in fig. 7) disposed at the inlet and outlet of the valve cavity, or a sealing gasket (as shown in fig. 1) attached and fixed to the inner wall of the valve cavity and matching with the shape of the inner wall of the valve cavity.

Before the inert gas filling reversing valve is used, the first gas inlet valve cavity 2 is kept in a normally open state under the action of the limiting assembly 9, and the second gas inlet valve cavity 3 and the gas outlet valve cavity 4 are kept in a normally closed state, as shown in fig. 4. When the first air inlet valve cavity 2 is kept in a normally open state, the air inlet of the valve cavity is opened. When the second air inlet valve cavity 3 and the air outlet valve cavity 4 are kept in a normally closed state, the valve cores of the second air inlet valve cavity 3 and the air outlet valve cavity 4 are respectively abutted against the valve body at the air inlet of the valve cavity, so that the air inlet of the valve cavity is kept closed.

When the gas flow is in the first set flow range, because the first gas inlet valve cavity 2 is normally open, the gas enters the connecting flow passage 5 along the first gas inlet valve cavity 2 and flows to the valve cavity gas inlet of the gas outlet valve cavity 4 along the connecting flow passage 5, the gas pushes the valve core in the gas outlet valve cavity 4 to move rightwards to compress the spring thereof, and the valve cavity gas inlet of the gas outlet valve cavity 4 is opened, so that the gas flows out of the valve body, as shown in fig. 5.

When the gas flow is increased to be within a second set flow range, the switch valve groups in the first gas inlet valve cavity 2 and the second gas inlet valve cavity 3 both move towards the gas outlets of the respective valve cavities under the action of gas pressure, in the process, gas flow pushes the valve core of the second gas inlet valve cavity 3 to move upwards from the gas inlet of the valve cavity to compress the spring of the valve core, the gas inlet of the valve cavity of the second gas inlet valve cavity 3 is opened, and gas flows into the connecting flow channel; meanwhile, at the moment of introducing gas, the first gas inlet valve cavity 2 is opened, so that the gas can enter the first gas inlet valve cavity 2, and the gas flow is overlarge at the moment and is larger than the maximum flow threshold value which can be borne by the switch valve group in the first gas inlet valve cavity 2, so that the gas can press the valve core of the first gas inlet valve cavity 2 to move downwards to compress the spring of the valve core, the valve core is clamped at the gas outlet of the valve cavity, and the gas outlet of the valve cavity of the first gas inlet valve cavity 2 is closed. The gas entering the connecting flow passage 5 flows along the connecting flow passage 5 to the valve cavity gas inlet of the gas outlet valve cavity 4, the gas pushes the valve core in the gas outlet valve cavity 4 to move rightwards to compress the spring thereof, and the valve cavity gas inlet of the gas outlet valve cavity 4 is opened, so that the gas flows out of the valve body, as shown in fig. 6.

In the practical use process, firstly, the sponge body is preset behind a certain welding line on the low-temperature pipeline so as to plug the low-temperature pipeline. A certain distance is kept between the sponge body and the welding line, and the sponge body is provided with an upper sampling port and a lower sampling port.

The air inlets of the first air inlet valve cavity 2 and the second air inlet valve cavity 3 are respectively connected with an air inlet pipe 16, and the air outlet of the valve cavity of the air outlet valve cavity 4 is connected with an air outlet pipe 17. The air inlet pipe connected with the first air inlet valve cavity 2 is connected with the upper sampling port, and the air inlet pipe connected with the second air inlet valve cavity 3 is connected with the lower sampling port.

Then, filling inert gas into the pipeline from the gas inlet of the low-temperature pipeline, and when the oxygen meter detects that the oxygen concentration in the gas discharged from the weld groove is not more than 2%, covering the weld groove by using an adhesive tape to achieve a sealing state.

Then, inert gas with the flow rate of 15-20L/min is filled into the pipeline from the gas inlet of the low-temperature pipeline, at the moment, the gas inlet of the valve cavity of the second gas inlet valve cavity 3 is opened, the gas outlet of the valve cavity of the first gas inlet valve cavity 2 is closed, and gas flows out of the valve body from the second gas inlet valve cavity 3, the connecting flow channel 5 and the gas outlet valve cavity 4, so that residual air in the pipeline is discharged, the content of gas discharged from the gas outlet pipe on the gas outlet valve cavity 4 is detected through a gas detection device, and most of the residual air is ensured to be discharged. The inflation time can be reduced by filling the inert gas with the flow rate of 15-20L/min into the pipeline, and the inflation efficiency is improved.

Although most of the residual air has been discharged, a small amount of residual air may accumulate above the interior of the pipeline due to the lighter specific gravity of the air, as shown in fig. 9. Therefore, after the inert gas with the flow rate of 15-20L/min is introduced for a period of time, the flow rate of the inert gas can be adjusted to 5-10L/min, at the moment, due to the reduction of the flow rate, under the elastic action of the spring, the valve core of the second gas inlet valve cavity 3 moves downwards to close the gas inlet of the valve cavity, the valve core of the second gas inlet valve cavity 3 moves upwards to open the gas outlet of the valve cavity, and the gas flows out of the valve body from the first gas inlet valve cavity 2, the connecting flow passage 5 and the gas outlet valve cavity 4, so that residual air accumulated above the pipeline is discharged. When the gas detection device detects that the oxygen content in the exhaust gas is zero, the residual air is completely discharged out of the pipeline, and the pipeline welding seam has welding conditions.

In the process of welding the pipeline, in order to ensure that the content of the inert gas in the pipeline is always maintained at the standard concentration, the first gas inlet valve cavity 2 can be kept normally open, namely the filling flow of the inert gas is maintained at 5-10L/min.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.