[Q&A Question 042] 2017.02.11
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This post was last edited by 955559 on 2017-7-21 at 21:53. [Q&A Question No. 042] 2017.02.11: What is clearance? The reference answer can be seen after responding; points will be awarded for identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) When the piston reaches the dead center, the gap between the piston and the cylinder head is called clearance. Petrochemical Area—“Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html The New Normal Cup—voting for the top 10 members of HaiChuan in 2016 is now underway; vote for the member you care about the most (please cast your valuable vote for the members in the Petrochemical Area). http://bbs.hcbbs.com/thread-1667649-1-1.html Summary thread of Q&A questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657793-1-1.html Summary thread of daily questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657794-1-1.html Summary thread of Q&A questions from 2016 (all updates completed). http://bbs.hcbbs.com/thread-1597792-1-1.html Third round of selection for outstanding management members of HaiChuan. http://bbs.hcbbs.com/thread-1655902-1-1.html Petrochemical Area—“Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html Xiaomi phones are up for grabs. Thread for collecting chemical industry technical materials in the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes are waiting for you (Source: HaiChuan Chemical Forum)
Due to the requirements related to the compressor’s structure, manufacturing, assembly, and operation, certain spaces or gaps are left in parts of the cylinder; this space or gap is referred to as the clearance volume.
Due to the requirements related to the compressor’s structure, manufacturing, assembly, and operation, certain spaces or gaps are left in parts of the cylinder; this space or gap is referred to as the clearance volume.
Due to the requirements related to the compressor’s structure, manufacturing, assembly, and operation, certain spaces or gaps are left in parts of the cylinder; this space or gap is referred to as the clearance volume.
Conceptual things do not allow consistency; it’s according to Baidu**~~~
The gap between the piston of a piston compressor and the end wall of the cylinder.
Due to the requirements related to the compressor’s structure, manufacturing, assembly, and operation, certain spaces or gaps are left in parts of the cylinder; this space or gap is referred to as the clearance volume.
Due to the requirements related to the compressor’s structure, manufacturing, assembly, etc., certain areas within the cylinder need to have some space left; this space is known as clearance.
The gap refers to the distance between the obstacle and the transmission line during Fresnel diffraction; it is positive if there is an obstacle, and negative for the remaining space without an obstacle
Distance between the piston’s extreme position in a reciprocating compressor and the cylinder head
At the end of the exhaust process in a piston compressor, due to reasons such as the piston being unable to make contact with the wall at the end of the cylinder, a small amount of high-pressure gas inevitably remains inside the cylinder. The volume of the cylinder occupied by this high-pressure gas is known as the compressor’s clearance volume. The clearance volume consists of three parts: 1) VO1, which is the volume of the gap between the piston’s end face and the cylinder head when the piston reaches its dead center, in order to prevent the moving piston from colliding with the ends of the cylinder; 2) VO2, which is the volume of the annular gap existing between the working surface of the cylinder and the outer circumference of the piston (from the piston’s end face to the first piston ring); 3) VO3, which is the volume of the entire passage from the cylinder end face to the valve leaflets. Obviously, at the end of the exhaust stage in a cycle, since there is still high-pressure gas remaining in the clearance volume that has not been exhausted, the presence of this clearance volume directly reduces the compressor’s exhaust volume. At the same time, the high-pressure gas remaining in the clearance volume expands first during the initial stage of the piston’s return movement. Only when this gas has expanded to a pressure in the cylinder that is equal to or slightly lower than the pressure in the intake pipe (intake pressure) can the cylinder begin to draw in air. Therefore, the presence of the clearance volume also results in a delay in the intake process as well as a reduction in the amount of air drawn in. A decrease in the volume of air inhaled will ultimately affect the volume of exhaust gas from the compressor as well. Furthermore, the gas in the clearance volume expands and is compressed alternately as the piston moves back and forth, forcing the compressor to perform unnecessary work on this gas continuously. In summary, the clearance volume has an impact on the capacity and efficiency of a compressor; an excessively large clearance volume will cause a sharp decline in the compressor’s capacity and efficiency. Therefore, while ensuring the safe operation of the compressor, the clearance volume should be as small as possible. However, an excessively small clearance volume increases the risk of collision between the piston and the cylinder head cover; therefore, when determining the size of the clearance volume, the requirements for safe operation must be taken into account first.