CN201100490Y - Direct buried steam insulation pipe - Google Patents

Abstract

The utility model relates to an engineering facility, namely a direct-buried steam insulation pipe. The existing direct-buried steam insulation pipe with a polyurethane foam insulation layer has a relatively low applicable temperature, so the method of laying pipes in trenches is still used to transport high-temperature steam, which is costly and has serious heat loss. For this reason, this new insulation pipe is developed. This insulation pipe is composed of a steel pipe 1, a polyurethane foam insulation layer 2, and a polyethylene protective layer 3. Its characteristics are: there is a composite silicate insulation layer 4 between the steel pipe 1 and the polyurethane foam insulation layer 2. This insulation pipeline has a simple structure, low cost, outstanding insulation and heat insulation performance, its water resistance and corrosion resistance and various performance indicators meet the standards of direct-buried steam pipes, can be competent for steam transportation operations below 500°C, construction costs and maintenance costs are greatly reduced, and the service life is more than 30 years, thereby better solving the transportation problem of high-temperature and high-pressure steam.

Description

Direct buried steam insulation pipe

Technical field

The utility model relates to an engineering facility, namely a directly buried steam heat preservation pipe.

Background technique

Many factories and mines need to transport steam through steam pipelines. Such steam pipelines should have good anti-corrosion and thermal insulation properties to prolong the life of the pipeline and reduce heat loss. For this reason, present steam pipeline is added slag wool or asbestos ash insulation layer outside steel pipe, and insulation layer is wrapped with glass fiber layer, and pipeline is placed in the ditch, and above stamps sealing. In this method, the temperature of the pipe surface is still very high, and the heat loss is relatively serious. Due to the heat inside and outside the pipe, the deformation is aggravated, and more expanders need to be installed to compensate for the deformation. The installation of the expander will increase the cost of the pipeline. In addition to the cost of the trench, the construction cost of the existing steam pipeline remains high, and it is difficult to meet the requirements of energy saving and consumption reduction. In order to solve this problem, a kind of polyurethane insulation pipe has been released on the market in recent years. That is, a polyurethane foam insulation layer is added outside the steel pipe, and a layer of polyethylene protection pipe is used outside the insulation layer, and a foam molding process is adopted to make the steel pipe placed in a tight seal. Compared with the above-mentioned slag wool or asbestos ash and glass fiber insulation pipeline, the heat loss of this pipeline is reduced by more than 70%. It can omit trenches, reduce expanders, and be directly buried underground, saving a lot of construction investment and maintenance costs. However, the applicable temperature of this kind of polyurethane insulation pipe is lower than 120°C, but in actual projects, it is often required to reach 320-400°C, and the highest is 500°C. It can be seen that the scope of application of the existing polyurethane foam insulation pipe is too small to meet the transportation requirements of high-temperature and high-pressure steam, and cannot completely replace the trench-type steam pipeline.

Contents of the invention

The purpose of this utility model is to provide a direct-buried steam insulation pipe that meets the requirements of direct-buried steam pipelines in various indicators such as water resistance and anti-corrosion, and has a significant heat insulation effect, and can be competent for steam transportation operations at 500°C.

The above object is achieved by the following technical solutions: develop a direct-buried steam insulation pipe, the inside of this insulation pipe is a steel pipe, there is a polyurethane foam insulation layer in the middle, and a layer of polyethylene is placed outside the polyurethane foam insulation layer The protective layer is characterized in that there is a composite silicate insulation layer between the steel pipe and the polyurethane foam insulation layer.

Said composite silicate insulation layer is a mixed layer composed of perlite, insulation cotton and adhesive.

There is an isolation layer between the polyurethane foam insulation layer and the composite silicate insulation layer.

Said isolation layer is an airtight layer surrounded by tinfoil or aluminum foil, and the outside of the airtight layer is a fiberglass layer made of glass fiber and resin.

The thickness of the composite silicate insulation layer is 25-40% of the outer diameter of the steel pipe.

The thickness of the polyurethane foam insulation layer is 25-30% of the outer diameter of the steel pipe.

The direct-buried steam insulation pipe made by the above technical scheme can work normally between -40 and 500°C, the heat loss rate is 0.017-0.024Kcal/mhc, and its water resistance, corrosion resistance and other indicators have reached direct According to the requirements of buried steam pipelines, the amount of expanders is further reduced, construction costs and maintenance costs are greatly reduced, and the service life is more than 30 years, thus better solving the problem of high-temperature and high-pressure steam transportation.

Description of drawings

Fig. 1 is the front view of first kind of embodiment;

Fig. 2 is the left view of first kind of embodiment;

Fig. 3 is the front view of the second embodiment;

Fig. 4 is an enlarged cross-sectional view of the isolation layer of the second embodiment.

It can be seen in the figure: steel pipe 1, polyurethane foam insulation layer 2, polyethylene protective layer 3, composite silicate insulation layer 4, isolation layer 5, airtight layer 6, glass fiber reinforced plastic layer 7, magnesium oxide coating layer 8

Detailed ways

The first embodiment: as shown in Fig. 1 and Fig. 2, this direct-buried steam insulation pipe has many similarities with the existing polyurethane foam insulation pipe. The polyurethane foam insulating layer 2 that polyurethane foam is surrounded, the outermost is the polyethylene protective layer 3 that is made of high-pressure polyethylene thin-walled pipe. The difference is that between the steel pipe 1 and the polyurethane foam insulation layer 2, there is an additional layer of composite silicate insulation layer 4. This insulation layer 4 is made of perlite, thermal insulation cotton, adhesive. The adhesive can use inorganic silicon high temperature glue. The insulation cotton is selected from silicon cotton, Qi cotton, Russian cotton and glass cotton. At the same time, inorganic raw materials such as sepiolite and expanded aluminum silicate can also be added. The ratio of the above-mentioned raw materials is relatively broad. For example, in terms of volume, perlite accounts for 30-40%, and various cottons account for 30-40%. The processing method is to make a composite silicate insulation layer 4 outside the steel pipe, and its thickness should be 25-40% of the outer diameter of the steel pipe. Then the pipe body is sent into the foaming machine, and the polyethylene protective layer 3 is placed on the outside, and the polyurethane foam insulation layer 2 is filled between the polyethylene protective layer 3 and the composite silicate insulation layer 4, and the polyurethane foam insulation The thickness of layer 2 is 25-30% of the outer diameter of the steel pipe. Taking a steel pipe with an outer diameter of 219mm as an example, the thickness of the composite silicate insulation layer 4 is 60-80mm, and the thickness of the polyurethane foam insulation layer 2 is 60-70mm. This kind of pipeline has higher water resistance and anticorrosion performance than polyurethane foam insulation pipe, so it can be directly buried. Its high temperature resistance is particularly outstanding. When the steam temperature in the steel pipe reaches 500°C, the surface temperature of the pipe is close to normal temperature, so the structural deformation is small, and the number of expanders is less than that of polyurethane foam insulation pipes. Its thermal conductivity is ≤0.045, heat loss rate is 0.017-0.024Kcal/mhc, and the service life is guaranteed to be more than 30 years, which can completely replace the trench steam pipeline.

The second embodiment: as shown in FIG. 3 , an insulating layer 5 is added outside the composite silicate insulation layer 4 . As can be seen from Fig. 4, the isolation layer 5 has three layers, one layer is an airtight layer 6 formed by wrapping with tin foil or aluminum foil, and the second layer is a glass fiber reinforced plastic layer 7 made of glass fiber and resin. The third layer is to apply one deck of magnesium oxide coating layer 8 outside the fiberglass layer. The three layers of materials are interpenetrated and tightly combined, which significantly improves the overall strength of the composite silicate insulation layer 4, and further shields heat dissipation, and better protects the polyurethane foam insulation layer 2 from high temperature.

Claims (6)

1. A direct-buried steam insulation pipe, this insulation pipe is made of a steel pipe (1) inside, a polyurethane foam insulation layer (2) in the middle and a polyethylene protective layer (3) outside, its characteristics In that: between the steel pipe (1) and the polyurethane foam insulation layer (2), there is a layer of composite silicate insulation layer (4). 2. The directly buried steam insulation pipe according to claim 1, characterized in that: there is a layer of isolation layer (5) between the polyurethane foam insulation layer (2) and the composite silicate insulation layer (4). ). 3. The direct-buried steam insulation pipe according to claim 2, characterized in that: said isolation layer (5) is an airtight layer (6) surrounded by tin foil or aluminum foil, and the outside of the airtight layer (6) is glass The fiberglass layer (7) that fiber and resin are made of. 4. The directly buried steam insulation pipe according to claim 3, characterized in that: the glass fiber reinforced plastic layer (7) of the isolation layer (5) is covered with a magnesium oxide coating layer (8). 5. The direct-buried steam insulation pipe according to claim 1, characterized in that: the thickness of the composite silicate insulation layer (4) is 25-40% of the outer diameter of the steel pipe (1). 6. The direct-buried steam insulation pipe according to claim 5, characterized in that: the thickness of the polyurethane foam insulation layer (2) is 25-30% of the outer diameter of the steel pipe (1).

Images