Piston ring design for reciprocating piston engines
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Our company’s pistons are of the single-stage, double-acting type; the support ring is located in the middle, with piston rings on both sides. However, there is 1 piston ring on the cover side and 2 on the shaft side. What is the reason for this? Since they are all of the single-stage type, with the inlet and outlet connected...
What is the import and export pressure? What is the piston diameter? Firstly, whether on the shaft side or the cover side, the piston ring serves a sealing function simultaneously; therefore, either shaft 1 of cover 2 or shaft 2 of cover 1 should be acceptable. I think, after calculation, only 3 piston rings are needed to meet the sealing requirements.
3.5 kilograms in, 6.5 kilograms out. Diameter 910, well, that makes sense
Which company designed it? It feels weird somehow, three support rings! Three piston rings! The pressure is also not low; it would be more appropriate to design it as a support ring with four piston rings. What is the purpose of those two small holes each on the support ring groove? Is it a through-hole?
The piston is large; considering weight, 3 support rings were designed. They are not through-holes, and positioning blocks are used to install these support rings. These support rings are not complete rings – they only exist in the lower part – so positioning is necessary.
Vertical or horizontal? In our original design, the support rings are on the outside, while the piston rings are in the middle.
For the horizontal type, it should be possible to design the support rings either on the inside or outside; personally, I think this has little impact
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With such a large diameter, the piston plus piston rod is extremely heavy; therefore, designers must first consider the support issues. The weight of the piston plus piston rod, along with the lubrication conditions, directly affect the width of the support rings. After that, the layout of the piston rings is considered. The number of piston rings is determined by factors such as the pressure difference between inlet and outlet, lubrication conditions, and the molecular weight of the gas medium. The pressure difference has the greatest influence; in your case, since the pressure difference is very small, three piston rings are sufficient. When the number of piston rings is low and the pressure difference is small, overlapping ring designs can be used, which also provides good sealing performance and fully meets the requirements. Furthermore, the external design of the piston rings is reasonable, as it results in minimal clearance and high operational efficiency.
The hole should be the pin hole for positioning the support ring pin