First, let's take a look at the technological process of directly buried insulated steel pipes. First, let's take a look at the insulation layout of directly buried insulation pipes. They are divided into three parts according to different steps: drag reduction layer, heat expansion zone of material steel tube, cold and free movement of contraction belt, pure hard insulation layer, high temperature resistance, interface temperature between green insulation layer, foam free carbonized steel pipe, normal movement of transmission medium, separation, reflection layer and green. The color foam material does not enter the pure hard high temperature resistant layer, and reflects part of the heat of the high temperature resistant layer. It's because they have different external coatings.

直埋保温管是一种保温性能好，加可靠，工程造价低的直埋预制保温管。如此避免了外观温度转变产生的外观变形使外观出现裂缝。标准弯头角度：30度、45度、60度、90度

Directly buried insulation pipe is a kind of prefabricated insulation pipe with good thermal insulation performance, safety and reliability, and low engineering cost. In this way, the appearance deformation caused by the appearance temperature transformation is avoided, and the appearance cracks appear. Standard elbow angle: 30 degrees, 45 degrees, 60 degrees, 90 degrees

聚氨酯预制直埋保温弯头应用：广泛用于液体、气体的输送管网，化工管道保温工程石油、化工、集中供、空调通风管道、市政工程管道转弯处中。与空气层结构相比，在同等保温厚度下可降低外壁温度8-13°c。聚氨酯泡沫保温无缝钢管聚氨酯直埋保温管广泛应用于不同产品中。钢套钢直埋蒸汽保温管保温管（包括弯头、三通、四通）是一种保温性能好，加可靠，工程造价低的直埋预制保温管。防水、耐腐蚀、耐老化：中频加热法利用管道余热同时固化两者，不需要分别涂覆和固化。外部滑动型。

Polyurethane prefabricated directly buried insulation elbow application: widely used in liquid and gas transmission pipe network, chemical pipeline insulation engineering, petroleum, chemical, centralized supply, air conditioning and ventilation pipe, municipal engineering pipeline bend. Compared with the air layer structure, the outer wall temperature can be reduced by 8-13 ° C under the same insulation thickness. Polyurethane foam insulation seamless steel tube price polyurethane directly buried insulation pipe is widely used in different products. Steel sleeve steel directly buried steam insulation pipe (including elbow, tee, cross) is a kind of directly buried prefabricated insulation pipe with good thermal insulation performance, safety and reliability, and low engineering cost. Waterproof, corrosion resistance, aging resistance: medium frequency heating method uses waste heat of pipeline to solidify both at the same time, without coating and curing separately. External sliding type.

保温层材料为密度60kg/m380kg/m3的硬质聚氨酯泡沫，充分添满钢管与套管之间的间隙，并具有一定的粘接强度，使钢管、外套管及保温层三者之间形成一个牢固的整体。聚氨酯泡沫具有良好的机械性能和绝热性能，通常情况下可耐温120℃,通过改性或与其它隔热材料组合可耐温180℃。

The insulating layer material is a rigid polyurethane foam with a density of 60kg/m3 to 80kg/m3. The gap between the steel pipe and the casing is fully filled and has certain bonding strength, so that a solid whole can be formed between the three parts of the steel pipe, the outer sleeve pipe and the insulation layer. Polyurethane foam has good mechanical properties and thermal insulation properties. Under normal circumstances, it can withstand temperatures of 120 degrees Celsius. It can withstand temperature of 180 degrees by modifying or combining with other insulation materials.

保温性能好，热损失仅为传统管材的25%，长期运行可节约大量能源，显著降低能源成本。具有很强的防水和耐腐蚀能力，不需附设管沟，可直接埋入地下或水中，施工简便迅速，综合造价低。在低温条件下也具有良好的耐腐蚀和耐冲击性，可直接埋入地下冻土。使用寿命可达30-50年，正确的安装和使用可使管网维修费用极低。可设置报警系统。

The heat loss is only 25% of that of the traditional pipe material. The long-term operation can save a lot of energy and significantly reduce the energy cost. It has strong waterproof and corrosion resistance, and can be directly buried in the ground or water without pipe trench. The construction is simple and rapid, and the comprehensive cost is low. It also has good corrosion resistance and impact resistance at low temperature, and can be directly buried in the underground frozen soil. The service life can be up to 30-50 years, and the maintenance cost of pipe network can be very low if it is installed and used correctly. Alarm system can be set.