TY - THES

T1 - Re-design of a polymer oil wiper for reciprocating compressors

AU - Radler, Bernhard

N1 - embargoed until 01-06-2022

PY - 2017

Y1 - 2017

N2 - The present thesis discusses the potential of re-designing an existing oil wiper ring, which is a vital part of any reciprocating compressor. Its function is the prevention of oil loss from the crankcase of a compressor and thereby causing high operational costs and pollution of the compressed gas. Furthermore, the product is designed to compensate occurring wear to enhance its lifetime. The project was initialised by field reports of performance problems particularly in application of compressors in the PET blow moulding industry. These compressors are characterised by high rotational speeds and small spaces between crankcase and cylinder. An additional reason for a product re-design are the high manufacturing costs. The first part of the work was an investigation of the product requirements. To start a focused re-design of the product it was necessary to evaluate the performance of the current product. Therefore an application like test scenario was designed. It enables to measure the oil wiping performance of the oil wiper ring during its operation in a reciprocating compressor. The current product consists of a polymer ring with four parts, a metallic garter spring and a metallic lug spring. One part of the product optimisation was found in replacing the metallic lug spring by a polymer spring to reduce the high manufacturing costs and to prevent damage of the piston rod surface. With prototypes of this concept a thorough evaluation of the mechanical behaviour was done. The result is that a replacement with the selected material and design is feasible but further investigation is necessary to gain a marketable product. The geometry of the current polymer ring design bears the potential of reducing the production costs and improving the oil wiping performance. Several concepts addressing these problems are shown. The new ring designs follow different approaches like reducing the number of single parts (up to one-body uncut ring), enhancing the number of wiping edges or different approaches of wear compensation. To determine the best concept further evaluation of the oil wiping performance is necessary.

AB - The present thesis discusses the potential of re-designing an existing oil wiper ring, which is a vital part of any reciprocating compressor. Its function is the prevention of oil loss from the crankcase of a compressor and thereby causing high operational costs and pollution of the compressed gas. Furthermore, the product is designed to compensate occurring wear to enhance its lifetime. The project was initialised by field reports of performance problems particularly in application of compressors in the PET blow moulding industry. These compressors are characterised by high rotational speeds and small spaces between crankcase and cylinder. An additional reason for a product re-design are the high manufacturing costs. The first part of the work was an investigation of the product requirements. To start a focused re-design of the product it was necessary to evaluate the performance of the current product. Therefore an application like test scenario was designed. It enables to measure the oil wiping performance of the oil wiper ring during its operation in a reciprocating compressor. The current product consists of a polymer ring with four parts, a metallic garter spring and a metallic lug spring. One part of the product optimisation was found in replacing the metallic lug spring by a polymer spring to reduce the high manufacturing costs and to prevent damage of the piston rod surface. With prototypes of this concept a thorough evaluation of the mechanical behaviour was done. The result is that a replacement with the selected material and design is feasible but further investigation is necessary to gain a marketable product. The geometry of the current polymer ring design bears the potential of reducing the production costs and improving the oil wiping performance. Several concepts addressing these problems are shown. The new ring designs follow different approaches like reducing the number of single parts (up to one-body uncut ring), enhancing the number of wiping edges or different approaches of wear compensation. To determine the best concept further evaluation of the oil wiping performance is necessary.

KW - Produktentwicklung

KW - Ölabstreifring

KW - Hubkolbenverdichter

KW - Product development

KW - Oil wiper

KW - Reciprocating compressor

M3 - Master's Thesis

ER -