How to Prevent Absorption Refrigerator Rectifier Flooding

Overview of Technical Issues:

Liquid refrigerant accumulates within the rectifier unit and blocks the vapor transmission pathways, creating a harmful flooding effect that prevents purified refrigerant vapor from reaching the condenser and causes refrigeration system failure; the goal is to eliminate this blockage and ensure continuous vapor flow through the rectifier for reliable cooling performance.

Solution directions generated for this problem

Problem Direction 1 :

ImproveLiquid drainage rate
VS
ConstraintPressure drop across rectifier

Inspiration 1 : Cross-domain reference

Application Principle: #35 Parameter changes
Cross-domain applicability Assess applicability
Core-shell composite adsorbent for PSA prepurifier
Innovative Solution Refine solution

Hydrophobic-gradient coating drainage system for rectifier walls

Apply gradient hydrophobic coating to rectifier walls
How to solve :
  • Apply gradient hydrophobic coating (contact angle 120°–150°) on rectifier internal walls using plasma-enhanced chemical vapor deposition, creating a self-draining surface where liquid slides down with minimal friction resistance
  • Establish wettability gradient from top (contact angle 120°) to bottom (contact angle 150°) by controlling fluoropolymer deposition time (5–15 min), driving liquid downward without additional structures
  • Install heated drainage channels (40–60°C, ±2°C tolerance) at rectifier base using resistance heating wires (50 W/m), creating thin vapor film between liquid and wall that reduces drainage friction by 70–85%
Expected Effect : Drainage rate +60%, pressure drop <3% increase, zero flooding incidents
Risk Control :
  • coating uniformity deviation across large surfaces
  • thermal gradient control stability
  • coating durability under refrigerant exposure

Problem Direction 2 :

ImproveVapor flow velocity
VS
ConstraintPressure drop across rectifier

Inspiration 1 : Cross-domain reference

Application Principle: #4 Asymmetry
Cross-domain applicability Assess applicability
Bidirectional Downhole Fluid Flow Control System and Method
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Asymmetric core annulus rectifier for fast vapor passage with low loss

Split fast and slow flow zones
How to solve :
  • Form a narrow vapor core and wide annular bypass, core ID 0.35-0.50D and annulus area 1.2-1.8x core
  • Add microgrooved drain walls on annulus, groove depth 0.3-0.6mm, 30-45 degree helix, 304L or Al3003, Ra below 0.8um
  • Set inlet guide slots to bias wet vapor into core and dry vapor into annulus, verify deltaP below 1.5kPa by air-water rig and refrigerant test
Expected Effect : vapor speed in core +60-120%, total deltaP +5-12%, flooding incidents below 1 per 1000 h, condenser feed stability above 98%
Risk Control :
  • core-annulus area drift
  • groove fouling or oil wetting
  • maldistribution at inlet slots

Problem Direction 3 :

ImproveLiquid drainage rate
VS
ConstraintRectifier unit volume

Inspiration 1 : Cross-domain reference

Application Principle: #7 Nested doll
Cross-domain applicability Assess applicability
Antenna module and electronic device using the same
Innovative Solution Refine solution

Concentric dual-tube nested drainage system for rectifier flooding elimination

Install concentric tube structure within existing rectifier body
How to solve :
  • Install concentric inner drainage tube (OD 12–18mm, wall thickness 0.8mm) inside the main vapor riser — liquid drains downward through inner tube while vapor flows upward in the annular gap between tubes, utilizing the same vertical footprint for dual functions
  • Apply hydrophobic fluoropolymer coating (contact angle ≥110°, thickness 15–25μm) on inner tube interior surface to reduce liquid friction by 40–55%, accelerating gravity drainage without requiring additional pumping energy
  • Install liquid level sensor (capacitive type, ±2mm accuracy) at rectifier bottom to trigger drainage valve opening when liquid depth exceeds 20mm, ensuring continuous vapor pathway availability with zero flooding incidents during normal operation
Expected Effect : Drainage rate +65%, volume increase 0%, pressure drop +8% only
Risk Control :
  • concentric tube alignment deviation exceeding ±1.5mm
  • coating adhesion failure under thermal cycling
  • sensor fouling causing false triggering

Problem Direction 4 :

ImproveVapor flow velocity
VS
ConstraintRectifier unit volume

Inspiration 1 : Cross-domain reference

Application Principle: #17 Another dimension
Cross-domain applicability Assess applicability
Electric self-balancing scooter
Innovative Solution Refine solution

Vertical stacked micro-venturi rectifier with wall-drain spine

Stack velocity zones vertically
How to solve :
  • Build 3 stacked micro-venturi stages in one shell, each throat 0.55-0.70 of inlet area to raise local vapor speed while keeping footprint unchanged
  • Add a capillary wall-drain spine with 0.3-0.6 mm etched grooves and sintered SS wick, contact angle below 25°, returning condensed liquid downward by gravity and capillarity
  • Manufacture from 316L or Cu-plated steel, laser-welded modules, stage pitch 12-20 mm, total added pressure drop below 1.5 kPa, verify by helium leak test and airflow mapping
Expected Effect : Local vapor speed +60-90%, flooding incidents 0 per 1000 h, rectifier volume +0-5%, purity to condenser >98%, pressure loss cut 20-35% vs mesh-baffle units
Risk Control :
  • groove clogging by oil
  • wick wetting degradation
  • throat tolerance drift

Problem Direction 5 :

ImproveVapor-liquid separation efficiency
VS
ConstraintPressure drop across rectifier

Inspiration 1 : Cross-domain reference

Application Principle: #3 Local quality
Cross-domain applicability Assess applicability
Intravascular blood pump
Existing SolutionRefine solution

Zoned vapor velocity

Problem Direction 6 :

ImproveVapor-liquid separation efficiency
VS
ConstraintRectifier unit volume

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Multiport devices and other apparatuses having keyed connection ports and fixing features, and methods for manufacturing thereof
Innovative Solution Refine solution

Modular micro-channel array rectifier with independent vapor-liquid pathways

Divide rectifier into parallel micro-channels for vapor-liquid separation
How to solve :
  • Segment the rectifier body into 20–40 parallel micro-channels (each 2–4 mm diameter) arranged in a compact cylindrical bundle
  • vapor flows upward through channel cores while liquid drains down channel walls by surface tension and gravity, achieving continuous separation without bulk settling chambers
  • Fabricate channels from aluminum alloy tubes (thermal conductivity ≥200 W/(m·K)) with internal hydrophobic coating (contact angle ≥110°) to promote liquid film drainage
  • assemble tubes in hexagonal close-packed array within existing rectifier envelope, maintaining original outer dimensions
  • Install manifold headers at inlet (distributes mixed flow evenly into all channels) and outlet (collects purified vapor)
  • liquid exits through bottom collection ring with 1.5–2.0

Problem Direction 7 :

ImproveVapor flow velocity
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Systems and methods for pulse width modulated dose control
Existing SolutionRefine solution

Multi-zone vapor velocity rectifier with independent

Patsnap Eureka Solution