Compressor Inlet Valve Timing Reduces Start-up Torque
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Solution Overview
Problem
High-pressure diaphragm compressors require large motors for start-up, leading to increased costs and power requirements due to high start-up torque, especially in applications like hydrogen refueling stations.
Innovation Solution
The compressor system reduces start-up torque by combining reduced inlet pressure with gas recycling and reversed start rotation of the crankshaft, utilizing a controller to manage valve operations during operation cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If motor size is increased to overcome start-up torque, then the compressor can start up from stand still, but costs and power supply requirements increase
Solution Approach 1:
The inlet valve is closed before the crankshaft stops rotating during shut-down, and opened after at least one completed compression stroke during start-up. This preliminary valve timing action reduces inlet pressure before start-up, thereby reducing the torque required to accelerate the crankshaft from stand still.
Solution Approach 2:
The invention changes the pressure parameter in the inlet volume by controlling the inlet valve timing. By closing the inlet valve before crankshaft stop and opening it after completion of compression stroke, the inlet pressure is reduced to a lower level during start-up, which directly reduces the start-up torque requirement.
2Power
If venting gas from inlet side prior to start-up, then start-up current is reduced, but gas is lost and additional venting operation is required
Solution Approach 1:
The compressor utilizes its own compression strokes to reduce inlet pressure naturally. By timing the inlet valve closure and opening appropriately, the compression process itself serves to reduce the pressure in the inlet volume, eliminating the need for external venting operations and associated gas losses.
Solution Approach 2:
The inlet valve is closed before the crankshaft stops rotating during shut-down, which preliminarily reduces the pressure in the inlet volume. This preliminary pressure reduction is achieved without venting gas, and the compressed gas remains in the system for potential reuse in the next compression cycle.
Data Source
Figure 1
Figure 2~6
AI summary
The present invention relates to a compressor system (1) comprising: a high-pressure diaphragm gas compressor (2) having a compressor inlet (3) and a compressor outlet (4). Wherein an inlet volume (5) is defined between a compressor inlet valve (6) and said compressor inlet, said compressor outlet is fluidly connected to a receiving vessel (7). A motor (8) configured to drive a crankshaft of said compressor. A controller (9) configured to control operation of said compressor, said compressor inlet valve and said motor, during a plurality of successive operation cycles. Wherein during a shut-down part of an operation cycle, said compressor inlet valve is configured for being closed before said crankshaft stop rotation, and wherein during a start-up part of a subsequent operation cycle, said compressor inlet valve is configured for being opened after at least one completed compression stroke.