CN103267611B - A kind of inflammable gas detector tube - Google Patents

Abstract

The invention relates to the field of gas leakage detection, in particular to a combustible gas detection tube. The detection tube includes a porous stainless steel tube and a rubbery composite selective permeation layer sleeved outside it, and the rubbery composite selective permeation layer consists of a non-woven material layer, a solvent-resistant porous film layer and a surface coating layer from the inside to the outside. layer. The nozzle joint adopts a quick loading and unloading structure design. The nozzle connection of the present invention is simple, convenient for engineering disassembly and assembly requirements; it can effectively improve the selective permeability and high permeation flux of leaking gas, and improve the positioning accuracy of the permeation detection method; it is convenient in design and processing, simple in structure, excellent in permeation effect, and Stable and reliable.

Description

A combustible gas detection tube

technical field

The invention relates to the field of gas leakage detection, in particular to a detection tube for detecting gas leakage.

Background technique

The safety of gas pipelines has attracted more and more attention in the field of oil and gas safety. Once gas leaks, it will not only cause huge resource losses and serious environmental pollution, but also cause fires and explosions, posing a huge threat to people's lives, property and living environment. . It is very necessary to detect the leakage point of the gas pipeline to ensure the safe operation of the gas pipeline. Gas pipeline leak detection is usually divided into direct leak detection method and indirect leak detection method according to the different measurement media. The direct leak detection method uses a detector installed outside the pipeline to directly detect the transport liquid or its volatile gas leaking out of the pipe, so as to achieve the purpose of leak detection; the indirect leak detection method relies on indirect and inferential detection, which is by means of detection Leakage causes changes in various parameters to achieve the purpose of leak detection. If there is pressure loss or flow volume imbalance in the gas pipeline, it is considered that there is a leak. In the direct leak detection method, there is a leak detection method based on a semi-permeable detection tube, such as the patent CN201110447412.6 "A Device and Method for Leakage Detection of Combustible Gas". The detection principle is that the pressure difference between the leaked oil and gas inside and outside the detection tube Driven by the concentration difference of the leaked gas and the leaked gas, it diffuses into the detection tube. Under the suction of the vacuum pump, the leaked oil gas flows to the detection end along with the fluid in the tube, and is detected by the combustible gas detector. The leak point is located according to the preset procedure. This detection method has the advantages of accurate detection, high positioning accuracy, stable and reliable detection system, and the main component of the detection device is a selective detection tube; for example, the patent ZL200520072790.0 "A leak detection tube for oil and gas pipelines" proposes to use perforated support liner, acetic acid The leak detection tube with semi-permeable characteristics is made of fiber tube and stainless steel mesh protective sleeve from the inside to the outside. However, due to the low strength of acetate fiber and its own moisture absorption, the wet strength is about 70% of the dry strength. In addition, acetate fiber is highly sensitive to alkaline environments, and deacetylation is prone to occur in alkaline soils, resulting in the strength of acetate fibers. decline. At the same time, the selective permeability of cellulose acetate to hydrocarbon gases is poor, and the flux is very low. The preparation method of the detection tube lacks a reasonable design for the connection between tubes and tubes. It is beneficial to the detection membrane tube made of acetate fiber material, but it is not suitable for the application in complex engineering environment. The invention develops a detection tube with excellent permeable gas performance, meeting the engineering strength permit, convenient for engineering construction and convenient disassembly, which is very necessary for fast, efficient and accurate location of leakage points based on the permeation detection method.

Contents of the invention

When the permeation detection method detects and locates the leaked gas, the structural design of the detection tube, surface coating treatment, material type, membrane pore diameter, porosity and other related parameters will have a greater impact on the permeability of the detection tube. The quality of the method directly affects the accuracy and speed of the entire detection result. The engineering strength that the detection tube can withstand and the convenience of disassembly and assembly of construction determine its operability and stability in the engineering environment. It is a detection tube that is easy to process, has excellent permeability, is stable and reliable, meets engineering strength requirements, and is convenient for engineering construction and disassembly. The detection tube utilizes the characteristic that the special polymer membrane has preferential permeability to hydrocarbons, so that under the action of a certain pressure, the gas molecules will preferentially pass through the polymer membrane while the air components are trapped. The enriched gas enters the detection tube, and the gas concentration is quickly accumulated, which is beneficial to the effective detection of the penetration detection method, thereby improving the detection accuracy and speed.

The technical solution adopted in the present invention is: a combustible gas detection tube, including a porous stainless steel tube and a rubbery composite permeable layer sleeved outside the porous stainless steel tube. The structure of the rubbery composite permeable layer is as follows from outside to inside: Surface coating, solvent resistant porous film layer and non-woven material layer.

In order to facilitate the loading and unloading of the detection tube, the nozzle joint adopts a quick loading and unloading structure design, and the two ends of the porous stainless steel tube are respectively a quick socket joint 1 and a short socket joint 2. The selected material is stainless steel, and the quick socket joint and the short socket joint are respectively welded to the two ends of the porous stainless steel tube 7 of the detection tube body 3 .

In the tube structure, the porous stainless steel tube 7 is used as a tube support body, which can ensure that the detection tube is in a negative pressure environment and meet the strength requirements of the tube body. The thickness of the support body can be selected from a range of (1-3) mm. The rubber-state composite selective permeation layer structure of the detection tube is composed of a surface coating 4 , a solvent-resistant porous membrane 5 and a non-woven material 6 . The specific composition of the permeable layer is: non-woven material 6 is used as the bottom layer, and the available materials include polypropylene, polyester or viscose, etc., which mainly play a supporting role for the rubbery composite permeable layer, and the selected thickness range (0.5～ 2) mm; the solvent-resistant porous membrane 5 can be used as the middle layer of the rubber composite permeable layer, and the optional materials are ABS, PSF/PBT, polyetherimide (PEI), polyether ether ketone (PEEK), polyacrylonitrile (PAN) resin, the role of the middle layer is to enhance the selective permeation performance of hydrocarbon organic vapors, and the selected thickness range is (10-100) μm; the surface coating 4 is the surface layer of the rubbery composite selective permeation layer, which is Dense silicone rubber polymer non-porous material layer, the thickness is relatively thin, the optional material is polydimethylsiloxane (PDMS), which not only has high permeability and high permeability to many organic vapors, but also has very Strong hydrophobicity. Optional thickness range (1-5) μm. The 6-layer non-woven material and the 5-layer solvent-resistant porous membrane have a loose structure, which mainly supports the detection tube membrane part, thereby enhancing the mechanical strength of the membrane layer part, and the surface coating 4 mainly plays a separation role. Based on the particularity of the application of the detection tube, the inner diameter of the detection tube can be selected as (5-20) mm, the thickness of the rubbery composite permeable layer can be selected as (1.5-3.2) mm, and the thickness of the porous stainless steel tube 7 (1 ~3) mm, the length of the tube is set to 20m as one tube.

Compared with the prior art, the present invention has the following advantages

(1) The nozzle of the detection tube is connected with a quick socket joint and a short socket, which is easy to operate and convenient for engineering disassembly and assembly requirements;

(2) The present invention adopts a rubbery composite permeable layer structure, which effectively improves the permeability and high permeation flux of leaked gas, and improves the positioning accuracy of the permeation detection method;

(3) The present invention has the advantages of convenient design and processing, simple structure, excellent penetration effect, and stable and reliable properties.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of a sample tube of the present invention;

Fig. 2 is a schematic diagram of the specific structure of the pipe body of the present invention.

1. Quick socket joint, 2. Short socket joint, 3. Tube body, 4. Surface coating, 5. Solvent resistant porous film, 6. Non-woven material, 7. Porous stainless steel tube.

detailed description

Figure 1 and Figure 2 respectively show the overall structure of the detection tube and the specific structure of the tube body. The structure of the detection tube includes a quick socket joint 1, a short socket joint 2 and a pipe body 3, and the two ends of the pipe body 3 are provided with matching quick socket joints 1 and short socket joints 2 made of stainless steel. In the specific implementation and application of the project, the quick socket joint 1 of one of the detection tubes is directly and quickly connected to the short socket joint 2 of the other adjacent detection tube, which can meet the use requirements of different lengths of detection tubes. The pipe body 3 is composed of a surface coating 4, a solvent-resistant porous membrane 5, a non-woven fabric material 6, and a porous stainless steel tube 7, wherein the porous stainless steel tube 7 is used as a support, and the surface coating, solvent-resistant porous membrane and non-woven fabric material are used as Rubbery composite permeable layer.

Example 1

The rubber-state composite permeable layer of the detection tube is tested for the penetration effect of the composite permeable layer under the conditions that the internal and external pressure difference is 30KPa, the surface temperature is 0°C, and the thickness of the composite permeable layer is 1.5mm. The results show that the composite permeable layer is impermeable , impermeable to air, natural gas permeability 2276±35cm ³ /m ² ·24h·30KPa, good permeability.

Example 2

The rubber-state composite permeable layer of the detection tube is tested for the penetration effect of the composite permeable layer under the conditions that the internal and external pressure difference is 30KPa, the surface temperature is 0°C, and the thickness of the composite permeable layer is 3.2mm. The results show that the composite permeable layer is impermeable , impermeable to air, natural gas permeability 1826±32cm ³ /m ² ·24h·30KPa, good permeability.

Example 3

The rubber-state composite permeable layer of the detection tube is tested for the penetration effect of the composite permeable layer under the conditions of internal and external pressure difference of 80KPa, surface temperature of 0°C, and composite permeable layer thickness of 1.5mm. The results show that the composite permeable layer is impermeable , impermeable to air, natural gas permeability 3276±45cm ³ /m ² ·24h·30KPa, good permeability.

Example 4

The rubber-state composite permeable layer of the detection tube is tested for the penetration effect of the composite permeable layer under the conditions that the internal and external pressure difference is 80KPa, the surface temperature is 0°C, and the thickness of the composite permeable layer is 3.2mm. The results show that the composite permeable layer is impermeable , impermeable to air, natural gas permeability 2826±36cm ³ /m ² ·24h·30KPa, good permeability.

Claims (4)

1. A combustible gas detection tube, comprising a porous stainless steel tube and a rubbery composite selective permeable layer sleeved outside it, characterized in that, the rubbery composite selective permeable layer is non-woven fabric material from inside to outside Layer, solvent-resistant porous film layer and surface coating, the surface coating material is polydimethylsiloxane. 2. The combustible gas detection tube according to claim 1, characterized in that the mouth joint of the porous stainless steel pipe has a quick socket joint at one end and a short socket joint at the other end. 3. The combustible gas detection tube according to claim 1 or 2, characterized in that the thickness of the porous stainless steel tube is 1-3 mm; the thickness of the non-woven material layer is 0.5-2 mm; the thickness of the solvent-resistant porous film layer is 10-100 μm; The thickness of the surface coating is 1-5 μm. 4. The combustible gas detection tube according to claim 3, characterized in that the inner diameter of the detection tube is 5-20mm.