Why Axial Fans Cannot Be Used Inside Mattress Systems? Blower Selection Logic for High-Resistance Applications

In medical equipment and electric mattress systems, airflow management is increasingly becoming a critical design requirement rather than a secondary function. However, a common engineering question arises:

Why are axial fans unsuitable for internal mattress ventilation, while high-static-pressure blowers are required?

This article explains the issue from airflow mechanics, system resistance, and fan selection perspectives, with reference to JENTECH DC blower series.

1. Why Mattress Interiors Are Considered High-Resistance Airflow Systems

Electric medical mattresses are typically composed of multi-layer structures, including:

• High-density foam support layers
• Pressure distribution layers
• Waterproof breathable fabrics
• Airflow diffusion layers

From an airflow perspective, this creates a system where:

Air can enter the structure, but cannot easily penetrate or pass through it.

This type of system is classified as:

High-resistance, low-permeability, semi-enclosed airflow environment

The core challenge is not airflow generation, but:

• Whether air can penetrate the structure
• Whether airflow can be maintained
• Whether air distribution can remain uniform

2. Why Axial Fans Fail in Mattress Applications

Axial fans are designed with the following characteristics:

• Straight-through axial airflow
• Performance dependent on open space diffusion
• Limited static pressure capability

In high-resistance environments such as mattress systems, this leads to three major failure modes:

1. Inability to penetrate internal structure

Air remains near the surface and does not reach deeper layers.

2. Rapid static pressure decay

Airflow drops significantly as resistance increases.

3. Non-uniform airflow distribution

Cooling or ventilation remains localized instead of distributed.

Therefore, axial fans are suitable for:

• Open-area ventilation
• External device cooling
• Low-resistance airflow systems

but not for embedded mattress airflow applications.

3. Why Blowers Are More Suitable: Centrifugal Structure Advantage

Unlike axial fans, centrifugal blowers operate with a different airflow mechanism:

• Air intake from rear side
• Pressure increase via impeller rotation
• Side discharge airflow output
• High static pressure generation

Key advantages in high-resistance environments include:

✔ Higher static pressure capability

Allows air to overcome structural resistance.

✔ Better performance in confined spaces

Suitable for embedded and compact system integration.

✔ Pressure-driven airflow behavior

Air is pushed through the structure rather than diffused across it.

4. Engineering Case Study 1: 76×70×20mm DC Blower (JB7620 Series)

This compact blower series is designed for medium-space-constrained embedded applications.

1. Key Specifications

• Size: 76×70×20mm
• Bearing type: Dual ball bearing
• Operating temperature: -20°C to 70°C
• Compact high-static-pressure design

2. Performance Overview (12V Series)

• JB7620B12L-1: 0.698 inH₂O / 8.6 CFM
• JB7620B12H-1: 1.059 inH₂O / 10.1 CFM
• JB7620B12U-1: 1.453 inH₂O / 11.5 CFM

Key Characteristics:

• Gradual static pressure increase
• Stable airflow output
• Suitable for medium-resistance embedded systems

3. Application Scope

• Local airflow modules in medical mattresses
• Compact enclosed cooling systems
• Low-profile embedded ventilation structures

5. Engineering Case Study 2: 97×95×33mm DC Blower (JB9733 Series)

This series is designed for high-static-pressure applications in more demanding environments.

1. Key Specifications

• Size: 97×95×33mm
• Larger impeller structure
• Enhanced pressure capability
• Optimized for deep airflow penetration

2. Performance Comparison (12V Series)

• JB9733B12L-1: 1.041 inH₂O / 28.5 CFM
• JB9733B12H-1: 2.796 inH₂O / 46.8 CFM
• JB9733B12U-1: 4.164 inH₂O / 57.1 CFM

Engineering Insight:

3. Application Scope

• High-density medical mattress systems
• High-resistance duct structures
• Enclosed airflow circulation systems
• Multi-layer filtration or foam structures

6. Fan Selection Logic for High-Resistance Systems

In mattress and similar enclosed airflow systems, fan selection must follow three engineering principles:

1. Static Pressure Priority Principle

System resistance determines performance limits, not airflow rating.

2. Structural Integration Principle

Key considerations include:

• Embedded installation capability
• Height and space constraints
• Compact system integration

3. Resistance Matching Principle

• Low resistance → Axial fan
• Medium resistance → Compact blower (JB7620)
• High resistance → High-static-pressure blower (JB9733)

7. Conclusion

The reason axial fans cannot be used in mattress systems is not insufficient airflow, but:

Insufficient static pressure to overcome high-resistance structures.

In high-density medical mattress applications, centrifugal high-static-pressure blowers are required to achieve effective airflow penetration and uniform distribution.

The JENTECH DC blower series (JB7620 and JB9733) provides scalable solutions from medium to high static pressure levels, supporting a wide range of high-resistance airflow engineering applications.

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