【Q&A Question 255】December 31, 2016
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This post was last edited by liuquan1100 on 2016-12-31 08:20. [Q&A Question 255] 2016.12.31 – Unnoticed, the Q&A section has been updated for 255 days now, without any interruption. As a new year is approaching, the numbering of questions and answers will start from 0. We strive to continue the tradition established in the previous year by sharing good questions with everyone. Why is a specified time required for cranking a reciprocating compressor? Refer to the answer after reading it again; scoring is based on identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Too short a rotation time may fail to reveal problems, and it also prevents the oil film from covering the bearings evenly ； Excessive cranking time can lead to dry friction, causing damage to the machine. Summary post of Q&A from 2016 (updated up to December~~~~) http://bbs.hcbbs.com/thread-1597792-1-1.html New Normal Cup–2016 HAICHUAN Top 10 Selection – Please recommend candidates http://bbs.hcbbs.com/thread-1654112-1-1.html Third round of HAICHUAN Outstanding Management Members selection http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: HAICHUAN Chemicals Forum)
After the compressor is shut down while still hot, the residual heat in the rotor prevents it from bending under the thermal stress caused by its own weight.
It is mainly to check whether the compressor is stuck, in order to prevent equipment components from getting stuck due to rust, oil adhesion, or bent shafts.
Prevent deformation caused by gravity
If the cranking time is too short, and the compressor has not completed one full rotation or has rotated too few times, it is not possible to identify any problems, nor can a proper oil film be established in the friction pairs before the motor starts. Therefore, 5 minutes is generally specified as the appropriate cranking time. However, too long a cranking time is also undesirable, as the compressor’s speed is quite low during cranking, and it is not possible to maintain an oil film at such low speeds for an extended period; if the amount of lubricating oil is not sufficient, dry friction may occur.
Deliver lubricating oil to the areas that require lubrication in order to establish an oil film
First is to prevent shaft bending and shaft corrosion. Secondly, regular turning of the shaft is necessary to ensure even stress distribution. Third, ensure that the equipment is always in a standby state.
Too much time will cause wear on the shaft
Support moderators, support the addition of a hydrogen production section to prevent bearing bending and pump jamming, as well as for lubrication and rust prevention!