One-Gate Screw Compressor Speed Control to Reduce Compression Loss
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Solution Overview
Problem
The existing one-gate screw compressor experiences compression loss when controlling capacity by returning refrigerant from the compression chamber to the suction side, leading to inefficiencies in refrigerant handling and increased pressure loss.
Innovation Solution
A one-gate screw compressor design with a screw rotor and a gate rotor having a tooth-to-groove ratio greater than or equal to 2.5, where the screw rotor rotates at an angle greater than 180°, and a speed adjuster increases the rotational speed beyond standard electric motor limits, allowing for higher rotational speeds up to 4500 r/min, reducing leakage and discharge pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If capacity is controlled by unloading (returning refrigerant from compression chamber to suction side), then capacity control is achieved, but compression loss increases
Solution Approach 1:
The patent changes the operating parameters by increasing rotational speed beyond rated speed (above 3000 r/min) and adjusting the tooth-to-groove ratio (T/S ≥ 2.5), which modifies the compression characteristics and reduces the need for unloading, thereby reducing compression loss while maintaining capacity control capability
Solution Approach 2:
The patent employs dynamic speed adjustment capability, allowing the screw rotor to operate at variable speeds above the rated speed. This dynamic operation enables the compressor to maintain optimal compression ratios across different capacity requirements, reducing the reliance on unloading and minimizing compression loss
2Loss of energy
If rotational speed is increased above rated speed, then leakage loss is reduced, but motor power requirements increase
Solution Approach 1:
The patent changes the gear ratio parameter to enable the screw rotor to rotate at speeds significantly higher than the motor's rated speed. This parameter change allows the system to achieve reduced leakage loss at high rotor speeds while the motor operates within its rated power capabilities through appropriate gear reduction
3Loss of energy
If the number of teeth T to screw grooves S ratio is increased to ≥2.5, then pressure loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a particular parameter range for the tooth-to-groove ratio (T/S ≥ 2.5, with T between 10-15 and S being 3 or 4). This standardized parameter selection balances the need for reduced pressure loss with manufacturing feasibility, as these specific ratios can be achieved with conventional gear manufacturing processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces compression loss, leakage, and discharge pressure loss while maintaining efficient refrigerant handling, stabilizing the seasonal coefficient of performance and improving overall compressor performance.
Implementation Method 1
an electric motor (15) configured to rotate the screw rotor (30)
Implementation Method 2
a screw rotor (30) having an outer peripheral surface with a plurality of screw grooves (31), and configured to be rotated
Data Source
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AI summary
A screw compressor with one gate rotor includes a gate rotor (40) meshing with a screw rotor (30). Rotation of the screw rotor (30) at an angle greater than 180° allows the screw compressor to perform a stroke from start of compression to completion of discharge. The screw compressor further includes a speed adjuster (19) configured to adjust the rotational speed of the screw rotor (30).