Screw compressor
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Solution Overview
Problem
Screw compressors face efficiency losses due to fluid leakage through clearance between the screw rotor and casing, and potential contact between the slide valve and screw rotor caused by thermal expansion and pressure differences, leading to reliability issues.
Innovation Solution
The implementation of key grooves with trapezoidal and dovetail shapes on the slide valve and casing, along with a matching key, restricts the slide valve's rotational movement, maintaining a necessary clearance and preventing contact with the screw rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the clearance between the slide valve and screw rotor is reduced to minimize fluid leakage, then operational efficiency is improved, but the risk of contact between the slide valve and screw rotor increases due to thermal expansion and pressure differences
Solution Approach 1:
A key mechanism is introduced as an intermediary element between the slide valve and the casing. The key fits into a key groove on the slide valve and a corresponding key groove on the casing, preventing the slide valve from rotating or moving circumferentially. This allows the clearance to be minimized for efficiency while the key ensures the slide valve cannot contact the screw rotor even under thermal expansion or pressure differential conditions
2Loss of energy
If the clearance between the screw rotor and casing is reduced to minimize fluid leakage, then compression efficiency is improved, but manufacturing precision requirements increase to maintain consistent small clearance
Solution Approach 1:
The key and key groove mechanism provides self-aligning and self-compensating features. The key automatically positions the slide valve in the correct circumferential location, and the trapezoidal dovetail shape of the key groove provides a wedge effect that ensures consistent clearance without requiring extremely tight manufacturing tolerances on the clearance surfaces themselves
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 configuration ensures reliable operation by maintaining clearance between the slide valve and screw rotor, minimizing efficiency losses and preventing damage from contact, even under varying pressure and temperature conditions.
Implementation Method 1
key grooves with trapezoidal and dovetail shapes on the slide valve and casing, along with a matching key, restricts the slide valve's rotational movement
Data Source
Figure 1
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AI summary
A screw compressor includes a casing forming an outer shell, a screw shaft located in the casing, the screw shaft being configured to be rotationally driven, a screw rotor fixed to the screw shaft, the screw rotor including a tooth groove with a spiral shape on an outer circumferential surface of the screw rotor, a gate rotor including a plurality of gate-rotor tooth portions to be fitted in the tooth groove of the screw rotor, the gate rotor forming a compression chamber together with the casing and the screw rotor, and a slide valve provided in a slide groove formed on an inner cylindrical surface of the casing, the slide valve being configured to be slidably movable in a rotational-axis direction of the screw rotor. Key grooves are formed facing each other on an outer surface of the slide valve and on an inner surface of the casing, and a key common to the key grooves is inserted in the key grooves.