Reciprocating Compressor Pressure-Drop Chamber for Dry Packing Sealing
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Solution Overview
Problem
Reciprocating compressors face limitations in achieving high discharge pressures due to high differential pressures across piston rod pressure packings, especially with dry packings, which restrict the maximum allowable discharge pressure.
Innovation Solution
Incorporating a pressure-drop chamber between the gas compression cylinder and the crosshead guide, maintained at a pressure lower than the delivery pressure and higher than ambient pressure, to divide the differential pressure across the piston rod pressure packings, reducing the maximum differential pressure across each packing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dry piston rod pressure packing is used to prevent gas contamination, then sealing reliability is improved, but the maximum allowable discharge pressure is limited due to high differential pressure across the packing
Solution Approach 1:
The invention introduces a pressure-drop chamber that segments the pressure distribution along the piston rod. By creating an intermediate pressure zone between the compression chamber and the distance piece, the total differential pressure is divided into two smaller differentials: one across the first pressure packing and another across the second pressure packing. This segmentation allows each packing to operate within acceptable pressure limits while maintaining reliable sealing for high discharge pressure applications
Solution Approach 2:
The pressure-drop chamber acts as an intermediary element between the high-pressure compression chamber and the low-pressure distance piece. This intermediate chamber, maintained at a pressure lower than delivery pressure but higher than ambient pressure, mediates the pressure transition and reduces the stress on individual pressure packings, enabling the use of dry packings at higher discharge pressures
2Stress or pressure
If the differential pressure across the piston rod pressure packing is reduced, then the maximum allowable discharge pressure is increased, but the contact pressure of the sealing rings against the piston rod is reduced
Solution Approach 1:
Instead of reducing the pressure differential across a single packing, the invention segments the total pressure differential into two smaller differentials across two separate packings. Each packing experiences a manageable pressure differential that maintains adequate contact pressure for sealing, while the cumulative effect allows the compressor to achieve higher discharge pressures than would be possible with a single packing
Data Source
AI summary
The reciprocating compressor comprises a compressor frame, a crankshaft and a connecting rod, connecting the crankshaft to a crosshead. A piston rod connects a piston to the crosshead. The piston reciprocates in a gas compression cylinder. At least one pressure-drop module is positioned between the gas compression cylinder and a crosspiece guide. The piston rod extends from the gas compression cylinder through a pressure-drop chamber of the pressure-drop module. Also disclosed herein is a method of operating a reciprocating compressor.