What are the reasons for the high temperature of the piston rod in the cyclic hydrogen compressor? ?
Thread Content
Our factory has a two-stage reciprocating compressor that uses hydrogen as the working medium; it operates with oil-free lubrication and relies on cooling water. Every time after maintenance and testing, the piston rod reaches high temperatures. The problems were resolved after being identified in the first two instances, but high temperatures occurred again after this latest maintenance. What could be the cause? I would appreciate advice from those with more experience. The gas seal gaps were all assembled in accordance with the drawing specifications, and no issues were found with the nitrogen seal and cooling water.
Is there any pulling force on the piston rod? What is the axial clearance of the packing ring, and what is the clearance of the final flow-blocking ring?
It’s likely that the clearance for filling the assembly is too small
There is some friction on the piston rod, and it appears slightly blackened. The axial clearance of the packing ring is around 0.50 mm according to the manufacturer’s specifications; the specification for the clearance of the final flow-control ring is 0.40–0.70 mm, while we set it at 0.63 mm during assembly. Is it also related to the tension of the packing ring spring?
The gap is not small; it falls within the range specified in the installation drawings, and we assemble it at the upper limit
One reason is that the gap between the fillers is too small; this can be ruled out if the assembly is done properly. Secondly, it is whether the cooling water circuit is unobstructed or if the flow rate is too low.
Check the location where friction occurs on the piston rod to see if it is in contact with the packing box, and what material the flow-blocking ring is made of
Is there any leakage in the medium? Or is there a problem with the installation of the ring set inside the stuffing box?
Quality issue with the filler; the coefficient of thermal expansion is too high.
The friction on the piston rod occurs at the area where the packing is located; I replaced the spring in the packing yesterday, and now the temperature is basically normal. Both the flow-blocking ring and the packing are made of PTFE. Is it related to thermal expansion?