seamless steel pipe
Seamless steel pipe should be used for ammonia refrigeration pipeline.
Check the pipeline
The pipeline shall be carefully inspected before installation, and there shall be no defects such as cracks, sand holes and serious corrosion.
Clean the pipeline
Before welding, the pipeline shall be purged, derusted and decontaminated, and the inner wall shall be wiped with cotton cloth. After derusting, the outer wall of the pipeline shall be painted with antirust paint in time.
electro-weld
Seamless steel pipes should be welded by electric welding, and small diameter pipes can be welded by gas welding. After welding, the welding slag at the joint of the inner and outer walls of the pipeline shall be removed in time, and the joint shall not have serious defects such as biting meat, slag inclusion, porosity, cracks and flash. When the pipe diameter is reduced, the reducing pipe should be adopted.
flanged connection
Flange connection should adopt concave-convex sealing surface flange with good sealing performance, use asbestos cardboard as gasket, and seal the surface of gasket with butter.
threaded connection
When making threaded connection with small-diameter nozzles such as ammonia valves of equipment, thick-walled seamless steel pipes or round steel lathes should be used for thread processing.
Slope requirement
When installing the pipeline, the pipeline should be kept horizontal and vertical where there is no slope regulation. However, in the horizontal section of compressor suction and exhaust, the horizontal section from condenser to accumulator, the horizontal section of liquid pipe from pressure regulating station to evaporation exhaust pipe and the horizontal section of ammonia inlet pipe, a certain slope should be set during construction. See the figure for slope and aspect requirements.
Locally concave downward
During installation, it should be ensured that there is no local downward depression on the water pipeline of each gaseous refrigerant, because the downward bent part will form a liquid pocket and hinder the gaseous refrigerant, and there should be no local upward convex part on the horizontal pipeline of each liquid refrigerant. For example, in the pipeline between the condenser and the evaporator, if there is a local upward bending pipe section, it is easy to form an airbag there, so that the air in the liquid pipe accumulates here, and the liquid is not easy to pass smoothly.
Stewed elbow
Piping elbows should use simmered elbows as far as possible.
Steel thimble
When the pipeline passes through the wall or floor, steel casing should be added, and there should be enough space between the casing and the pipeline.
compensator
In the refrigeration pipeline, when the straight section of the low-pressure pipeline exceeds 100m, and the straight section of the high-pressure pipeline exceeds 50m, a compensator should be set. Generally, a square compensator is used without pre-stretching.